mmc: support BKOPS feature for eMMC

Enable eMMC background operations (BKOPS) feature.

If URGENT_BKOPS is set after a response, note that BKOPS are required. After all I/O requests are finished, run BKOPS if required. Should read/write operations be requested during BKOPS, first issue HPI to interrupt the ongoing BKOPS and then service the request.
If BKOPS-STATUS is upper than LEVEL2, need to check until clear the BKOPS-STATUS vaule.

If you want to enable this feature, set MMC_CAP2_BKOPS. And if you want to set the BKOPS_EN bit in ext_csd register, use the MMC_CAP2_INIT_BKOPS.

When BKOPS_STATUS is Level-3, if we're waiting for done, it spent 60~80sec.
So Added timeout value. if timeout value is set to 0, send hpi command.

Signed-off-by Jaehoon Chung <[email protected]>

Signed-off-by Kyungmin Park <[email protected]>

---
Changelog V8:
- Remove host->lock spin lock reviewed by Adrian
- Support periodic start bkops
- when bkops_status is level-3, if timeout is set to 0, send hpi.
- Move the start-bkops point
Changelog V7:
- Use HPI command when issued URGENT_BKOPS
- Recheck until clearing the bkops-status bit.
Changelog V6:
- Add the flag of check-bkops-status.
(For fixing async_req problem)
- Add the capability for MMC_CAP2_INIT_BKOPS.
(When unset the bkops_en bit in ext_csd register)
- modify the wrong condition.
Changelog V5:
- Rebase based on the latest mmc-next.
- modify codes based-on Chris's comment
Changelog V4:
- Add mmc_read_bkops_status
- When URGENT_BKOPS(level2-3), didn't use HPI command.
- In mmc_switch(), use R1B/R1 according to level.
Changelog V3:
- move the bkops setting's location in mmc_blk_issue_rw_rq
- modify condition checking
- bkops_en is assigned ext_csd[EXT_CSD_BKOPS_EN] instead of "1"
- remove the unused code
- change pr_debug instead of pr_warn in mmc_send_hpi_cmd
- Add the Future consideration suggested by Per
Changelog V2:
- Use EXCEPTION_STATUS instead of URGENT_BKOPS
- Add function to check Exception_status(for eMMC4.5)

---
 drivers/mmc/card/queue.c   |    2 +
 drivers/mmc/core/core.c    |  170
+++++++++++++++++++++++++++++++++++++++++++-
 drivers/mmc/core/host.c    |    1 +
 drivers/mmc/core/mmc.c     |   18 +++++
 drivers/mmc/core/mmc_ops.c |    4 +
 include/linux/mmc/card.h   |   16 ++++
 include/linux/mmc/core.h   |    5 ++
 include/linux/mmc/host.h   |    4 +
 include/linux/mmc/mmc.h    |   20 +++++
 9 files changed, 238 insertions(+), 2 deletions(-)

drivers/mmc/card/queue.c +2 -0

index e360a97..e4a2cde 100644
@@ -66,6 +66,8 @@ static int mmc_queue_thread(void *d)
 		spin_unlock_irq(q->queue_lock);
 
 		if (req || mq->mqrq_prev->req) {
+			if (mmc_card_doing_bkops(mq->card))
+				mmc_stop_bkops(mq->card);
 			set_current_state(TASK_RUNNING);
 			mq->issue_fn(mq, req);
 		} else {

drivers/mmc/core/core.c +7 -0

index 0b6141d..91a03d5 100644
@@ -175,6 +175,13 @@ void mmc_request_done(struct mmc_host *host, struct
 mmc_request *mrq)
 		if (mrq->done)
 			mrq->done(mrq);
 
+		/*
+		 * Check BKOPS urgency from each R1 response
+		 */
+		if (host->card && mmc_card_mmc(host->card) &&
+			(cmd->resp[0] & R1_EXCEPTION_EVENT))
+			mmc_card_set_check_bkops(host->card);
+
 		mmc_host_clk_release(host);
 	}

}

drivers/mmc/core/core.c +70 -0

@@ -245,6 +252,76 @@ mmc_start_request(struct mmc_host *host, struct
 mmc_request *mrq)
 	host->ops->request(host, mrq);
 }
 
+static void mmc_send_bkops_cmd(struct mmc_card *card)
+{
+	int err;
+
+	BUG_ON(!card);
+
+	err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
+			EXT_CSD_BKOPS_START, 1, 0);
+	if (err) {
+		pr_warning("%s: error %d starting bkops\n",
+			   mmc_hostname(card->host), err);
+		mmc_card_clr_need_bkops(card);
+		return;
+	}
+
+	mmc_card_clr_need_bkops(card);
+	mmc_card_set_doing_bkops(card);
+
+}
+
+void mmc_start_periodic_bkops(struct work_struct *work)
+{
+	struct mmc_host *host = container_of(work, struct mmc_host,
+			start_bkops.work);
+
+	mmc_card_set_check_bkops(host->card);
+
+	mmc_claim_host(host);
+	mmc_start_bkops(host->card);
+	mmc_release_host(host);
+}
+EXPORT_SYMBOL(mmc_start_periodic_bkops);
+
+/**
+ *	mmc_start_bkops - start BKOPS for supported cards
+ *	@card: MMC card to start BKOPS
+ *
+ *	Start background operations whenever requested.
+ *	when the urgent BKOPS bit is set in a R1 command response
+ *	then background operations should be started immediately.
+*/
+void mmc_start_bkops(struct mmc_card *card)
+{
+	BUG_ON(!card);
+	if (!card->ext_csd.bkops_en || !(card->host->caps2 & MMC_CAP2_BKOPS))
+		return;
+
+	if (mmc_card_check_bkops(card)) {
+		mmc_card_clr_check_bkops(card);
+		if (mmc_is_exception_event(card, EXT_CSD_URGENT_BKOPS)) {
+			if (card->ext_csd.raw_bkops_status)
+				mmc_card_set_need_bkops(card);
+		} else
+			mmc_card_clr_need_bkops(card);
+	}
+
+	/*
+	 * If card_need_bkops_flag didn't set, then do nothing just
+	 * return
+	 */
+	if (mmc_card_doing_bkops(card) || !mmc_card_need_bkops(card))
+		goto check_bkops;
+
+	mmc_send_bkops_cmd(card);
+
+check_bkops:
+	queue_delayed_work(system_nrt_wq, &card->host->start_bkops, 5 * HZ);
+}
+EXPORT_SYMBOL(mmc_start_bkops);
+
 static void mmc_wait_done(struct mmc_request *mrq)
 {

drivers/mmc/core/core.c +3 -1

 	complete(&mrq->completion);

@@ -348,8 +425,10 @@ struct mmc_async_req *mmc_start_req(struct mmc_host
 *host,
 	struct mmc_async_req *data = host->areq;
 
 	/* Prepare a new request */
-	if (areq)
+	if (areq) {
+		cancel_delayed_work_sync(&host->start_bkops);
 		mmc_pre_req(host, areq->mrq, !host->areq);
+	}
 
 	if (host->areq) {

drivers/mmc/core/core.c +4 -1

 		mmc_wait_for_req_done(host, host->areq->mrq);

@@ -359,8 +438,11 @@ struct mmc_async_req *mmc_start_req(struct mmc_host
 *host,
 	if (!err && areq)
 		start_err = __mmc_start_req(host, areq->mrq);
 
-	if (host->areq)
+	if (host->areq) {
 		mmc_post_req(host, host->areq->mrq, 0);
+		if (!areq && host->areq && mmc_card_mmc(host->card))
+			mmc_start_bkops(host->card);
+	}
 
 	 /* Cancel a prepared request if it was not started. */

drivers/mmc/core/core.c +0 -0

 	if ((err || start_err) && areq)

@@ -480,6 +562,84 @@ int mmc_wait_for_cmd(struct mmc_host *host, struct

mmc_command *cmd, int retries
EXPORT_SYMBOL(mmc_wait_for_cmd);

/**
+ * mmc_stop_bkops - stop ongoing BKOPS
+ * @card: MMC card to check BKOPS
+ *
+ * Send HPI command to interrupt ongoing background operations,
+ * to allow rapid servicing of foreground operations,e.g. read/
+ * writes. Wait until the card comes out of the programming state
+ * to avoid errors in servicing read/write requests.
+ */

drivers/mmc/core/core.c +76 -0

+int mmc_stop_bkops(struct mmc_card *card)
+{
+	int err = 0;
+	unsigned int timeout = 0x10000;
+	u32 status;
+
+	BUG_ON(!card);
+	cancel_delayed_work_sync(&card->host->start_bkops);
+
+	if (card->ext_csd.raw_bkops_status == EXT_CSD_BKOPS_LEVEL_3) {
+		do {
+			if (timeout == 0)
+				break;
+			mmc_claim_host(card->host);
+			mmc_send_status(card, &status);
+			mmc_release_host(card->host);
+
+			timeout--;
+		} while (R1_CURRENT_STATE(status) == R1_STATE_PRG);
+		if (timeout != 0)
+			goto done;
+	}
+
+	err = mmc_interrupt_hpi(card);
+
+done:
+	mmc_card_clr_doing_bkops(card);
+
+	return err;
+}
+EXPORT_SYMBOL(mmc_stop_bkops);
+
+int mmc_read_bkops_status(struct mmc_card *card)
+{
+	int err;
+	u8 ext_csd[512];
+
+	mmc_claim_host(card->host);
+	err = mmc_send_ext_csd(card, ext_csd);
+	mmc_release_host(card->host);
+	if (err)
+		return err;
+
+	card->ext_csd.raw_bkops_status = ext_csd[EXT_CSD_BKOPS_STATUS];
+	card->ext_csd.raw_exception_status = ext_csd[EXT_CSD_EXCEPTION_STATUS];
+
+	return 0;
+}
+EXPORT_SYMBOL(mmc_read_bkops_status);
+
+int mmc_is_exception_event(struct mmc_card *card, unsigned int value)
+{
+	int err;
+
+	err = mmc_read_bkops_status(card);
+	if (err) {
+		pr_err("%s: Didn't read bkops status : %d\n",
+		       mmc_hostname(card->host), err);
+		return 0;
+	}
+
+	/* In eMMC 4.41, R1_EXCEPTION_EVENT is URGENT_BKOPS */
+	if (card->ext_csd.rev == 5)
+		return 1;
+
+	return (card->ext_csd.raw_exception_status & value) ? 1 : 0;
+}
+EXPORT_SYMBOL(mmc_is_exception_event);
+
+/**
  *	mmc_set_data_timeout - set the timeout for a data command
  *	@data: data phase for command
  *	@card: the MMC card associated with the data transfer

@@ -2382,6 +2542,12 @@ int mmc_pm_notify(struct notifier_block
 *notify_block,
 	switch (mode) {
 	case PM_HIBERNATION_PREPARE:
 	case PM_SUSPEND_PREPARE:
+		if (host->card && mmc_card_mmc(host->card) &&
+				mmc_card_doing_bkops(host->card)) {
+			mmc_interrupt_hpi(host->card);
+			mmc_card_clr_doing_bkops(host->card);
+		}
+		cancel_delayed_work_sync(&host->start_bkops);
 
 		spin_lock_irqsave(&host->lock, flags);

drivers/mmc/core/core.c +0 -0

 		host->rescan_disable = 1;

drivers/mmc/core/host.c +1 -0

index 91c84c7..3b6a8e4 100644
@@ -330,6 +330,7 @@ struct mmc_host *mmc_alloc_host(int extra, struct
 device *dev)
 	spin_lock_init(&host->lock);
 	init_waitqueue_head(&host->wq);
 	INIT_DELAYED_WORK(&host->detect, mmc_rescan);
+	INIT_DELAYED_WORK(&host->start_bkops, mmc_start_periodic_bkops);
 #ifdef CONFIG_PM
 	host->pm_notify.notifier_call = mmc_pm_notify;

#endif

drivers/mmc/core/mmc.c +18 -0

index 2f0e11c..275555a 100644
@@ -463,6 +463,24 @@ static int mmc_read_ext_csd(struct mmc_card *card, u8
 *ext_csd)
 	}
 
 	if (card->ext_csd.rev >= 5) {
+		/* check whether the eMMC card support BKOPS */
+		if (ext_csd[EXT_CSD_BKOPS_SUPPORT] & 0x1) {
+			card->ext_csd.bkops = 1;
+			card->ext_csd.bkops_en = ext_csd[EXT_CSD_BKOPS_EN];
+			card->ext_csd.raw_bkops_status =
+				ext_csd[EXT_CSD_BKOPS_STATUS];
+			if (!card->ext_csd.bkops_en &&
+				card->host->caps2 & MMC_CAP2_INIT_BKOPS) {
+				err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
+					EXT_CSD_BKOPS_EN, 1, 0);
+				if (err)
+					pr_warning("%s: Enabling BKOPS failed\n",
+						mmc_hostname(card->host));
+				else
+					card->ext_csd.bkops_en = 1;
+			}
+		}
+
 		/* check whether the eMMC card supports HPI */
 		if (ext_csd[EXT_CSD_HPI_FEATURES] & 0x1) {

drivers/mmc/core/mmc.c +0 -0

 			card->ext_csd.hpi = 1;

drivers/mmc/core/mmc_ops.c +0 -0

index 69370f4..bc8da17 100644

Hi Jaehoon,
I see 2 issues with new patch:
1. New code starts BKOPS always with waiting for BUSY. (see comment below in the code)
2. Runtime suspend (mmc_suspend_host) do not checks that BKOPS is in progress,
this means, that CMD5 (slee) will fail.

In your previous patch (v7) was code:

(quoted diff) +6 -1

-	cmd.flags = MMC_RSP_SPI_R1B | MMC_RSP_R1B | MMC_CMD_AC;
+	cmd.flags = MMC_CMD_AC;
+	if (index == EXT_CSD_BKOPS_START &&
+	    card->ext_csd.raw_bkops_status < EXT_CSD_BKOPS_LEVEL_2)
+		cmd.flags |= MMC_RSP_SPI_R1 | MMC_RSP_R1;
+	else
+		cmd.flags |= MMC_RSP_SPI_R1B | MMC_RSP_R1B;

When level of raw_bkops_status is not critical, the host controller flags used
without waiting for BUSY line release. This means, that mmc queue thread will continue
to fetch requests while BKOPS still running on the card. Without this code, BKOPS will always be blocking till BKOPS done and using HPI for interrupt BKOPS on
new request is not need.
Why you removed this code?

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Hi Konstantin.

Quoted 8 lines · On 05/10/2012 11:46 PM, [email protected] wrote:

Hi Jaehoon,
I see 2 issues with new patch:
1. New code starts BKOPS always with waiting for BUSY. (see comment below
in the code)
2. Runtime suspend (mmc_suspend_host) do not checks that BKOPS is in progress,
this means, that CMD5 (slee) will fail.

You're right. it needs to check in progress. I will add them.

Quoted 13 lines

In your previous patch (v7) was code:

(quoted diff) +6 -1

-	cmd.flags = MMC_RSP_SPI_R1B | MMC_RSP_R1B | MMC_CMD_AC;
+	cmd.flags = MMC_CMD_AC;
+	if (index == EXT_CSD_BKOPS_START &&
+	    card->ext_csd.raw_bkops_status < EXT_CSD_BKOPS_LEVEL_2)
+		cmd.flags |= MMC_RSP_SPI_R1 | MMC_RSP_R1;
+	else
+		cmd.flags |= MMC_RSP_SPI_R1B | MMC_RSP_R1B;

Quoted 11 lines

When level of raw_bkops_status is not critical, the host controller flags
used
without waiting for BUSY line release. This means, that mmc queue thread will continue
to fetch requests while BKOPS still running on the card. Without this code, BKOPS will always be blocking till BKOPS done and using
HPI for interrupt BKOPS on
new request is not need.
Why you removed this code?

You're right. it's my mistake. Actually i modified to use with __mmc_switch().
As I remember, maybe you mentioned this point. right?
So i tried to use based on your review. it's missing in this patch.

Thank you for your comment. any other comments? If you have others, let me know, plz.

Enable eMMC background operations (BKOPS) feature.

If URGENT_BKOPS is set after a response, note that BKOPS are required. After all I/O requests are finished, run BKOPS if required. Should read/write operations be requested during BKOPS, first issue HPI to interrupt the ongoing BKOPS and then service the request.
If BKOPS-STATUS is upper than LEVEL2, need to check until clear the BKOPS-STATUS vaule.

If you want to enable this feature, set MMC_CAP2_BKOPS. And if you want to set the BKOPS_EN bit in ext_csd register, use the MMC_CAP2_INIT_BKOPS.

When BKOPS_STATUS is Level-3, if we're waiting for done, it spent 60~80sec. So Added timeout value. if timeout value is set to 0, send hpi command.

Signed-off-by Jaehoon Chung <[email protected]>

Signed-off-by Kyungmin Park <[email protected]>

---
Changelog V8:
       - Remove host->lock spin lock reviewed by Adrian
       - Support periodic start bkops
       - when bkops_status is level-3, if timeout is set to 0, send hpi.
       - Move the start-bkops point
Changelog V7:
       - Use HPI command when issued URGENT_BKOPS
       - Recheck until clearing the bkops-status bit. Changelog V6:
       - Add the flag of check-bkops-status.
         (For fixing async_req problem)
       - Add the capability for MMC_CAP2_INIT_BKOPS.
         (When unset the bkops_en bit in ext_csd register)
       - modify the wrong condition.
Changelog V5:
       - Rebase based on the latest mmc-next.
       - modify codes based-on Chris's comment
Changelog V4:
       - Add mmc_read_bkops_status
       - When URGENT_BKOPS(level2-3), didn't use HPI command.
       - In mmc_switch(), use R1B/R1 according to level. Changelog V3:
       - move the bkops setting's location in mmc_blk_issue_rw_rq
       - modify condition checking
       - bkops_en is assigned ext_csd[EXT_CSD_BKOPS_EN] instead of "1"
       - remove the unused code
       - change pr_debug instead of pr_warn in mmc_send_hpi_cmd
       - Add the Future consideration suggested by Per Changelog V2:
       - Use EXCEPTION_STATUS instead of URGENT_BKOPS
       - Add function to check Exception_status(for eMMC4.5)
---
 drivers/mmc/card/queue.c   |    2 +

 drivers/mmc/core/core.c    |  170 +++++++++++++++++++++++++++++++++++++++++++-
 drivers/mmc/core/host.c    |    1 +
 drivers/mmc/core/mmc.c     |   18 +++++
 drivers/mmc/core/mmc_ops.c |    4 +
 include/linux/mmc/card.h   |   16 ++++
 include/linux/mmc/core.h   |    5 ++
 include/linux/mmc/host.h   |    4 +
 include/linux/mmc/mmc.h    |   20 +++++
 9 files changed, 238 insertions(+), 2 deletions(-)

drivers/mmc/card/queue.c +2 -0

index e360a97..e4a2cde 100644
@@ -66,6 +66,8 @@ static int mmc_queue_thread(void *d)
                spin_unlock_irq(q->queue_lock);
 
                if (req || mq->mqrq_prev->req) {
+                       if (mmc_card_doing_bkops(mq->card))
+                               mmc_stop_bkops(mq->card);
                        set_current_state(TASK_RUNNING);
                        mq->issue_fn(mq, req);
                } else {

drivers/mmc/core/core.c +18 -0

index 0b6141d..91a03d5 100644
@@ -175,6 +175,13 @@ void mmc_request_done(struct mmc_host *host, struct mmc_request *mrq)
                if (mrq->done)
                        mrq->done(mrq);
 
+               /*
+                * Check BKOPS urgency from each R1 response
+                */
+               if (host->card && mmc_card_mmc(host->card) &&
+                       (cmd->resp[0] & R1_EXCEPTION_EVENT))
+                       mmc_card_set_check_bkops(host->card);
+
                mmc_host_clk_release(host);
        }
  }

@@ -245,6 +252,76 @@ mmc_start_request(struct mmc_host *host, struct mmc_request *mrq)
        host->ops->request(host, mrq);
  }
 
+static void mmc_send_bkops_cmd(struct mmc_card *card)
+{
+       int err;
+
+       BUG_ON(!card);
+
+       err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
+                       EXT_CSD_BKOPS_START, 1, 0);
+       if (err) {
+               pr_warning("%s: error %d starting bkops\n",
+                          mmc_hostname(card->host), err);

drivers/mmc/core/core.c +6 -0

+
+       mmc_claim_host(host);
+       mmc_start_bkops(host->card);
+       mmc_release_host(host);
+}
+EXPORT_SYMBOL(mmc_start_periodic_bkops);

drivers/mmc/core/core.c +5 -0

+               } else
+                       mmc_card_clr_need_bkops(card);
+       }
+
+       /*

drivers/mmc/core/core.c +30 -2

+}
+EXPORT_SYMBOL(mmc_start_bkops);
+
  static void mmc_wait_done(struct mmc_request *mrq)
  {
        complete(&mrq->completion);

@@ -348,8 +425,10 @@ struct mmc_async_req *mmc_start_req(struct mmc_host *host,
        struct mmc_async_req *data = host->areq;
 
        /* Prepare a new request */
-       if (areq)
+       if (areq) {
+               cancel_delayed_work_sync(&host->start_bkops);
                mmc_pre_req(host, areq->mrq, !host->areq);
+       }
 
        if (host->areq) {
                mmc_wait_for_req_done(host, host->areq->mrq);

@@ -359,8 +438,11 @@ struct mmc_async_req *mmc_start_req(struct mmc_host *host,
        if (!err && areq)
                start_err = __mmc_start_req(host, areq->mrq);
 
-       if (host->areq)
+       if (host->areq) {
                mmc_post_req(host, host->areq->mrq, 0);
+               if (!areq && host->areq && mmc_card_mmc(host->card))
+                       mmc_start_bkops(host->card);
+       }
 
         /* Cancel a prepared request if it was not started. */
        if ((err || start_err) && areq)

@@ -480,6 +562,84 @@ int mmc_wait_for_cmd(struct mmc_host *host, struct mmc_command *cmd, int retries
  EXPORT_SYMBOL(mmc_wait_for_cmd);
 
  /**
+ *     mmc_stop_bkops - stop ongoing BKOPS
+ *     @card: MMC card to check BKOPS
+ *
+ *     Send HPI command to interrupt ongoing background operations,
+ *     to allow rapid servicing of foreground operations,e.g. read/
+ *     writes. Wait until the card comes out of the programming state
+ *     to avoid errors in servicing read/write requests.
+ */
+int mmc_stop_bkops(struct mmc_card *card)
+{
+       int err = 0;
+       unsigned int timeout = 0x10000;
+       u32 status;
+
+       BUG_ON(!card);
+       cancel_delayed_work_sync(&card->host->start_bkops);
+
+       if (card->ext_csd.raw_bkops_status == EXT_CSD_BKOPS_LEVEL_3) {
+               do {
+                       if (timeout == 0)

drivers/mmc/core/core.c +32 -0

+
+       err = mmc_interrupt_hpi(card);
+
+done:
+       mmc_card_clr_doing_bkops(card);
+
+       return err;
+}
+EXPORT_SYMBOL(mmc_stop_bkops);
+
+int mmc_read_bkops_status(struct mmc_card *card)
+{
+       int err;
+       u8 ext_csd[512];
+
+       mmc_claim_host(card->host);
+       err = mmc_send_ext_csd(card, ext_csd);
+       mmc_release_host(card->host);
+       if (err)
+               return err;
+
+       card->ext_csd.raw_bkops_status = ext_csd[EXT_CSD_BKOPS_STATUS];
+       card->ext_csd.raw_exception_status = ext_csd[EXT_CSD_EXCEPTION_STATUS];
+
+       return 0;
+}
+EXPORT_SYMBOL(mmc_read_bkops_status);
+
+int mmc_is_exception_event(struct mmc_card *card, unsigned int value)
+{
+       int err;
+

drivers/mmc/core/core.c +6 -0

+
+       return (card->ext_csd.raw_exception_status & value) ? 1 : 0;
+}
+EXPORT_SYMBOL(mmc_is_exception_event);
+
+/**
  *     mmc_set_data_timeout - set the timeout for a data command
  *     @data: data phase for command
  *     @card: the MMC card associated with the data transfer

@@ -2382,6 +2542,12 @@ int mmc_pm_notify(struct notifier_block *notify_block,
        switch (mode) {

       case PM_HIBERNATION_PREPARE:
       case PM_SUSPEND_PREPARE:
+               if (host->card && mmc_card_mmc(host->card) &&
+                               mmc_card_doing_bkops(host->card)) {
+                       mmc_interrupt_hpi(host->card);
+                       mmc_card_clr_doing_bkops(host->card);
+               }
+               cancel_delayed_work_sync(&host->start_bkops);

               spin_lock_irqsave(&host->lock, flags); host->rescan_disable = 1;

drivers/mmc/core/host.c +1 -0

index 91c84c7..3b6a8e4 100644
@@ -330,6 +330,7 @@ struct mmc_host *mmc_alloc_host(int extra, struct device *dev)
        spin_lock_init(&host->lock);
        init_waitqueue_head(&host->wq);
        INIT_DELAYED_WORK(&host->detect, mmc_rescan);
+       INIT_DELAYED_WORK(&host->start_bkops, mmc_start_periodic_bkops);
  #ifdef CONFIG_PM
        host->pm_notify.notifier_call = mmc_pm_notify;
  #endif

drivers/mmc/core/mmc.c +0 -0

index 2f0e11c..275555a 100644
@@ -463,6 +463,24 @@ static int mmc_read_ext_csd(struct mmc_card *card, u8 *ext_csd)
        }
 
        if (card->ext_csd.rev >= 5) {

drivers/mmc/core/mmc.c +8 -0

+                               if (err)
+                                       pr_warning("%s: Enabling BKOPS failed\n",
+                                               mmc_hostname(card->host));
+                               else
+                                       card->ext_csd.bkops_en = 1;
+                       }
+               }
+
                /* check whether the eMMC card supports HPI */
                if (ext_csd[EXT_CSD_HPI_FEATURES] & 0x1) {
                        card->ext_csd.hpi = 1;

drivers/mmc/core/mmc_ops.c +4 -0

index 69370f4..bc8da17 100644
@@ -399,6 +399,10 @@ int mmc_switch(struct mmc_card *card, u8 set, u8 index, u8 value,
        if (err)
                return err;
 
+       /* No need to check card status in case of BKOPS switch*/
+       if (index == EXT_CSD_BKOPS_START)
+               return 0;
+
        /* Must check status to be sure of no errors */
        do {
                err = mmc_send_status(card, &status);

include/linux/mmc/card.h +0 -0

index d76513b..52b507d 100644
@@ -76,6 +76,9 @@ struct mmc_ext_csd {

       bool                    hpi_en;                 /* HPI enablebit */ bool                    hpi;                    /* HPI support bit */ unsigned int            hpi_cmd;                /* cmd used as HPI */
+       bool                    bkops;          /* background support bit */
+       bool                    bkops_en;       /* background enable bit */
+       u8                      raw_exception_status;   /* 53 */ unsigned int            data_sector_size;       /* 512 bytes or 4KB */ unsigned int            data_tag_unit_size;     /* DATA TAG UNIT size */ unsigned int            boot_ro_lock;           /* ro lock support */

include/linux/mmc/card.h +0 -0

@@ -93,6 +96,7 @@ struct mmc_ext_csd {

       u8                      raw_sec_erase_mult;     /* 230 */ u8                      raw_sec_feature_support;/* 231 */ u8                      raw_trim_mult;          /* 232 */
+       u8                      raw_bkops_status;       /* 246 */ u8                      raw_sectors[4];         /* 212 - 4 bytes */

       unsigned int            feature_support;

include/linux/mmc/card.h +3 -0

@@ -225,6 +229,9 @@ struct mmc_card {
  #define MMC_CARD_REMOVED       (1<<7)          /* card has been removed */
  #define MMC_STATE_HIGHSPEED_200        (1<<8)          /* card is in HS200 mode */
  #define MMC_STATE_SLEEP                (1<<9)          /* card is in sleep state */
+#define MMC_STATE_NEED_BKOPS   (1<<10)         /* card need to do BKOPS */
+#define MMC_STATE_DOING_BKOPS  (1<<11)         /* card is doing BKOPS */
+#define MMC_STATE_CHECK_BKOPS  (1<<12)         /* card need to check BKOPS */

       unsigned int            quirks;         /* card quirks */
 #define MMC_QUIRK_LENIENT_FN0  (1<<0)          /* allow SDIO FN0 writes outside of the VS CCCR range */ #define MMC_QUIRK_BLKSZ_FOR_BYTE_MODE (1<<1)   /* use func->cur_blksize */

include/linux/mmc/card.h +9 -0

@@ -391,6 +398,9 @@ static inline void __maybe_unused remove_quirk(struct mmc_card *card, int data)
  #define mmc_card_ext_capacity(c) ((c)->state & MMC_CARD_SDXC)
  #define mmc_card_removed(c)    ((c) && ((c)->state & MMC_CARD_REMOVED))
  #define mmc_card_is_sleep(c)   ((c)->state & MMC_STATE_SLEEP)
+#define mmc_card_need_bkops(c) ((c)->state & MMC_STATE_NEED_BKOPS)
+#define mmc_card_doing_bkops(c)        ((c)->state & MMC_STATE_DOING_BKOPS)
+#define mmc_card_check_bkops(c) ((c)->state & MMC_STATE_CHECK_BKOPS)
 
  #define mmc_card_set_present(c)        ((c)->state |= MMC_STATE_PRESENT)
  #define mmc_card_set_readonly(c) ((c)->state |= MMC_STATE_READONLY)

@@ -403,7 +413,13 @@ static inline void __maybe_unused remove_quirk(struct mmc_card *card, int data)
  #define mmc_card_set_ext_capacity(c) ((c)->state |= MMC_CARD_SDXC)
  #define mmc_card_set_removed(c) ((c)->state |= MMC_CARD_REMOVED)
  #define mmc_card_set_sleep(c)  ((c)->state |= MMC_STATE_SLEEP)
+#define mmc_card_set_need_bkops(c)     ((c)->state |= MMC_STATE_NEED_BKOPS)
+#define mmc_card_set_doing_bkops(c)    ((c)->state |= MMC_STATE_DOING_BKOPS)
+#define mmc_card_set_check_bkops(c) ((c)->state |= MMC_STATE_CHECK_BKOPS)
 
+#define mmc_card_clr_need_bkops(c)     ((c)->state &= ~MMC_STATE_NEED_BKOPS)
+#define mmc_card_clr_doing_bkops(c)    ((c)->state &= ~MMC_STATE_DOING_BKOPS)
+#define mmc_card_clr_check_bkops(c) ((c)->state &= ~MMC_STATE_CHECK_BKOPS)
  #define mmc_card_clr_sleep(c)  ((c)->state &= ~MMC_STATE_SLEEP)
  /*
  * Quirk add/remove for MMC products.

include/linux/mmc/core.h +5 -0

index 1b431c7..c920250 100644
@@ -134,6 +134,9 @@ struct mmc_host;
  struct mmc_card;
  struct mmc_async_req;
 
+extern int mmc_stop_bkops(struct mmc_card *);
+extern int mmc_read_bkops_status(struct mmc_card *);
+extern int mmc_is_exception_event(struct mmc_card *, unsigned int);
  extern struct mmc_async_req *mmc_start_req(struct mmc_host *,
                                           struct mmc_async_req *, int *);
  extern int mmc_interrupt_hpi(struct mmc_card *);

@@ -163,6 +166,8 @@ extern int mmc_can_sanitize(struct mmc_card *card);
  extern int mmc_can_secure_erase_trim(struct mmc_card *card);
  extern int mmc_erase_group_aligned(struct mmc_card *card, unsigned int from,
                                   unsigned int nr);
+extern void mmc_start_periodic_bkops(struct work_struct *work);
+extern void mmc_start_bkops(struct mmc_card *card);
  extern unsigned int mmc_calc_max_discard(struct mmc_card *card);
 
  extern int mmc_set_blocklen(struct mmc_card *card, unsigned int blocklen);

include/linux/mmc/host.h +2 -0

index 0707d22..186d146 100644
@@ -238,6 +238,8 @@ struct mmc_host {
  #define MMC_CAP2_BROKEN_VOLTAGE        (1 << 7)        /* Use the broken voltage */
  #define MMC_CAP2_DETECT_ON_ERR (1 << 8)        /* On I/O err check card removal */
  #define MMC_CAP2_HC_ERASE_SZ   (1 << 9)        /* High-capacity erase size */
+#define MMC_CAP2_INIT_BKOPS    (1 << 10)       /* To enable BKOPS */
+#define MMC_CAP2_BKOPS         (1 << 11)       /* BKOPS supported */
 

       mmc_pm_flag_t           pm_caps;        /* supported pm features */ unsigned int        power_notify_type;

include/linux/mmc/host.h +0 -0

@@ -320,6 +322,8 @@ struct mmc_host {
 

       unsigned int            actual_clock;   /* Actual HC clock rate */

+       struct delayed_work     start_bkops;    /* Periodic bkops start */ +
       unsigned long           private[0] ____cacheline_aligned; };

include/linux/mmc/mmc.h +11 -0

index d425cab..06afeb4 100644
@@ -139,6 +139,7 @@ static inline bool mmc_op_multi(u32 opcode)
  #define R1_CURRENT_STATE(x)    ((x & 0x00001E00) >> 9) /* sx, b (4 bits) */
  #define R1_READY_FOR_DATA      (1 << 8)        /* sx, a */
  #define R1_SWITCH_ERROR                (1 << 7)        /* sx, c */
+#define R1_EXCEPTION_EVENT     (1 << 6)        /* sx, a */
  #define R1_APP_CMD             (1 << 5)        /* sr, c */
 
  #define R1_STATE_IDLE  0

@@ -274,12 +275,15 @@ struct _mmc_csd {
  #define EXT_CSD_FLUSH_CACHE            32      /* W */
  #define EXT_CSD_CACHE_CTRL             33      /* R/W */
  #define EXT_CSD_POWER_OFF_NOTIFICATION 34      /* R/W */
+#define EXT_CSD_EXCEPTION_STATUS       54      /* RO */
  #define EXT_CSD_DATA_SECTOR_SIZE       61      /* R */
  #define EXT_CSD_GP_SIZE_MULT           143     /* R/W */
  #define EXT_CSD_PARTITION_ATTRIBUTE    156     /* R/W */
  #define EXT_CSD_PARTITION_SUPPORT      160     /* RO */
  #define EXT_CSD_HPI_MGMT               161     /* R/W */
  #define EXT_CSD_RST_N_FUNCTION         162     /* R/W */
+#define EXT_CSD_BKOPS_EN               163     /* R/W */
+#define EXT_CSD_BKOPS_START            164     /* W */
  #define EXT_CSD_SANITIZE_START         165     /* W */
  #define EXT_CSD_WR_REL_PARAM           166     /* RO */
  #define EXT_CSD_BOOT_WP                        173     /* R/W */

@@ -313,11 +317,13 @@ struct _mmc_csd {
  #define EXT_CSD_PWR_CL_200_360         237     /* RO */
  #define EXT_CSD_PWR_CL_DDR_52_195      238     /* RO */
  #define EXT_CSD_PWR_CL_DDR_52_360      239     /* RO */
+#define EXT_CSD_BKOPS_STATUS           246     /* RO */
  #define EXT_CSD_POWER_OFF_LONG_TIME    247     /* RO */
  #define EXT_CSD_GENERIC_CMD6_TIME      248     /* RO */
  #define EXT_CSD_CACHE_SIZE             249     /* RO, 4 bytes */
  #define EXT_CSD_TAG_UNIT_SIZE          498     /* RO */
  #define EXT_CSD_DATA_TAG_SUPPORT       499     /* RO */
+#define EXT_CSD_BKOPS_SUPPORT          502     /* RO */
  #define EXT_CSD_HPI_FEATURES           503     /* RO */
 
  /*

@@ -386,4 +392,18 @@ struct _mmc_csd {
  #define MMC_SWITCH_MODE_CLEAR_BITS     0x02    /* Clear bits which are 1 in value */
  #define MMC_SWITCH_MODE_WRITE_BYTE     0x03    /* Set target to value */
 
+/*
+ * BKOPS status level
+ */
+#define EXT_CSD_BKOPS_LEVEL_2          0x2
+#define EXT_CSD_BKOPS_LEVEL_3          0x3

Quoted 114 lines · Jaehoon Chung

Enable eMMC background operations (BKOPS) feature.

If URGENT_BKOPS is set after a response, note that BKOPS are required. After all I/O requests are finished, run BKOPS if required. Should read/write operations be requested during BKOPS, first issue HPI to interrupt the ongoing BKOPS and then service the request.
If BKOPS-STATUS is upper than LEVEL2, need to check until clear the BKOPS-STATUS vaule.

If you want to enable this feature, set MMC_CAP2_BKOPS. And if you want to set the BKOPS_EN bit in ext_csd register, use the MMC_CAP2_INIT_BKOPS.

When BKOPS_STATUS is Level-3, if we're waiting for done, it spent 60~80sec. So Added timeout value. if timeout value is set to 0, send hpi command.

Signed-off-by Jaehoon Chung <[email protected]>

Signed-off-by Kyungmin Park <[email protected]>

---
Changelog V8:
- Remove host->lock spin lock reviewed by Adrian
- Support periodic start bkops
- when bkops_status is level-3, if timeout is set to 0, send hpi.
- Move the start-bkops point
Changelog V7:
- Use HPI command when issued URGENT_BKOPS
- Recheck until clearing the bkops-status bit.
Changelog V6:
- Add the flag of check-bkops-status.
(For fixing async_req problem)
- Add the capability for MMC_CAP2_INIT_BKOPS.
(When unset the bkops_en bit in ext_csd register)
- modify the wrong condition.
Changelog V5:
- Rebase based on the latest mmc-next.
- modify codes based-on Chris's comment
Changelog V4:
- Add mmc_read_bkops_status
- When URGENT_BKOPS(level2-3), didn't use HPI command.
- In mmc_switch(), use R1B/R1 according to level.
Changelog V3:
- move the bkops setting's location in mmc_blk_issue_rw_rq
- modify condition checking
- bkops_en is assigned ext_csd[EXT_CSD_BKOPS_EN] instead of "1"
- remove the unused code
- change pr_debug instead of pr_warn in mmc_send_hpi_cmd
- Add the Future consideration suggested by Per
Changelog V2:
- Use EXCEPTION_STATUS instead of URGENT_BKOPS
- Add function to check Exception_status(for eMMC4.5)

---
 drivers/mmc/card/queue.c   |    2 +
 drivers/mmc/core/core.c    |  170 +++++++++++++++++++++++++++++++++++++++++++-
 drivers/mmc/core/host.c    |    1 +
 drivers/mmc/core/mmc.c     |   18 +++++
 drivers/mmc/core/mmc_ops.c |    4 +
 include/linux/mmc/card.h   |   16 ++++
 include/linux/mmc/core.h   |    5 ++
 include/linux/mmc/host.h   |    4 +
 include/linux/mmc/mmc.h    |   20 +++++
 9 files changed, 238 insertions(+), 2 deletions(-)

drivers/mmc/card/queue.c +2 -0

index e360a97..e4a2cde 100644
@@ -66,6 +66,8 @@ static int mmc_queue_thread(void *d)
               spin_unlock_irq(q->queue_lock);
 
               if (req || mq->mqrq_prev->req) {
+                       if (mmc_card_doing_bkops(mq->card))
+                               mmc_stop_bkops(mq->card);
                       set_current_state(TASK_RUNNING);
                       mq->issue_fn(mq, req);
               } else {

drivers/mmc/core/core.c +23 -0

index 0b6141d..91a03d5 100644
@@ -175,6 +175,13 @@ void mmc_request_done(struct mmc_host *host, struct mmc_request *mrq)
               if (mrq->done)
                       mrq->done(mrq);
 
+               /*
+                * Check BKOPS urgency from each R1 response
+                */
+               if (host->card && mmc_card_mmc(host->card) &&
+                       (cmd->resp[0] & R1_EXCEPTION_EVENT))
+                       mmc_card_set_check_bkops(host->card);
+
               mmc_host_clk_release(host);
       }
 }

@@ -245,6 +252,76 @@ mmc_start_request(struct mmc_host *host, struct mmc_request *mrq)
       host->ops->request(host, mrq);
 }
 
+static void mmc_send_bkops_cmd(struct mmc_card *card)
+{
+       int err;
+
+       BUG_ON(!card);
+
+       err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
+                       EXT_CSD_BKOPS_START, 1, 0);
+       if (err) {
+               pr_warning("%s: error %d starting bkops\n",
+                          mmc_hostname(card->host), err);
+               mmc_card_clr_need_bkops(card);
+               return;
+       }
+
+       mmc_card_clr_need_bkops(card);

drivers/mmc/core/core.c mmc_start_request(struct mmc_host *host, struct mmc_request *mrq) · line 275

Quoted 5 lines

drivers/mmc/core/core.c +5 -0

+       mmc_card_set_doing_bkops(card);
+
+}
+
+void mmc_start_periodic_bkops(struct work_struct *work)

There's nothing periodic about this function, by looking at the contents. Maybe this one should be called mmc_start_bkops ..

drivers/mmc/core/core.c mmc_start_request(struct mmc_host *host, struct mmc_request *mrq) · line 280

Quoted 6 lines

drivers/mmc/core/core.c +5 -0

+{
+       struct mmc_host *host = container_of(work, struct mmc_host,
+                       start_bkops.work);
+
+       mmc_card_set_check_bkops(host->card);

Why is this being set here. The condition should be in the caller context.

Quoted 10 lines

drivers/mmc/core/core.c +10 -0

+
+       mmc_claim_host(host);
+       mmc_start_bkops(host->card);
+       mmc_release_host(host);
+}
+EXPORT_SYMBOL(mmc_start_periodic_bkops);
+
+/**
+ *     mmc_start_bkops - start BKOPS for supported cards
+ *     @card: MMC card to start BKOPS

drivers/mmc/core/core.c mmc_start_request(struct mmc_host *host, struct mmc_request *mrq) · line 296

Quoted 6 lines

drivers/mmc/core/core.c +6 -0

+ *
+ *     Start background operations whenever requested.
+ *     when the urgent BKOPS bit is set in a R1 command response
+ *     then background operations should be started immediately.
+*/
+void mmc_start_bkops(struct mmc_card *card)

.. and this one should be called __mmc_start_bkops() ?

drivers/mmc/core/core.c mmc_start_request(struct mmc_host *host, struct mmc_request *mrq) · line 306

Quoted 11 lines

drivers/mmc/core/core.c +10 -0

+{
+       BUG_ON(!card);
+       if (!card->ext_csd.bkops_en || !(card->host->caps2 & MMC_CAP2_BKOPS))
+               return;
+
+       if (mmc_card_check_bkops(card)) {
+               mmc_card_clr_check_bkops(card);
+               if (mmc_is_exception_event(card, EXT_CSD_URGENT_BKOPS)) {
+                       if (card->ext_csd.raw_bkops_status)
+                               mmc_card_set_need_bkops(card);

This breaks abstraction. Why check ext_csd even after URGENT_BKOPS is set ?

Quoted 12 lines

drivers/mmc/core/core.c +11 -0

+               } else
+                       mmc_card_clr_need_bkops(card);
+       }
+
+       /*
+        * If card_need_bkops_flag didn't set, then do nothing just
+        * return
+        */
+       if (mmc_card_doing_bkops(card) || !mmc_card_need_bkops(card))
+               goto check_bkops;
+

drivers/mmc/core/core.c mmc_start_request(struct mmc_host *host, struct mmc_request *mrq) · line 321

Quoted 4 lines

drivers/mmc/core/core.c +4 -0

+       mmc_send_bkops_cmd(card);
+
+check_bkops:
+       queue_delayed_work(system_nrt_wq, &card->host->start_bkops, 5 * HZ);

IIUC, queue_delayed_work->start_bkops = mmc_start_periodic_bkops -> mmc_start_bkops -> queue_delayed_work
.. ad infinitum ?

Quoted 62 lines

drivers/mmc/core/core.c +36 -2

+}
+EXPORT_SYMBOL(mmc_start_bkops);
+
 static void mmc_wait_done(struct mmc_request *mrq)
 {
       complete(&mrq->completion);

@@ -348,8 +425,10 @@ struct mmc_async_req *mmc_start_req(struct mmc_host *host,
       struct mmc_async_req *data = host->areq;
 
       /* Prepare a new request */
-       if (areq)
+       if (areq) {
+               cancel_delayed_work_sync(&host->start_bkops);
               mmc_pre_req(host, areq->mrq, !host->areq);
+       }
 
       if (host->areq) {
               mmc_wait_for_req_done(host, host->areq->mrq);

@@ -359,8 +438,11 @@ struct mmc_async_req *mmc_start_req(struct mmc_host *host,
       if (!err && areq)
               start_err = __mmc_start_req(host, areq->mrq);
 
-       if (host->areq)
+       if (host->areq) {
               mmc_post_req(host, host->areq->mrq, 0);
+               if (!areq && host->areq && mmc_card_mmc(host->card))
+                       mmc_start_bkops(host->card);
+       }
 
        /* Cancel a prepared request if it was not started. */
       if ((err || start_err) && areq)

@@ -480,6 +562,84 @@ int mmc_wait_for_cmd(struct mmc_host *host, struct mmc_command *cmd, int retries
 EXPORT_SYMBOL(mmc_wait_for_cmd);
 
 /**
+ *     mmc_stop_bkops - stop ongoing BKOPS
+ *     @card: MMC card to check BKOPS
+ *
+ *     Send HPI command to interrupt ongoing background operations,
+ *     to allow rapid servicing of foreground operations,e.g. read/
+ *     writes. Wait until the card comes out of the programming state
+ *     to avoid errors in servicing read/write requests.
+ */
+int mmc_stop_bkops(struct mmc_card *card)
+{
+       int err = 0;
+       unsigned int timeout = 0x10000;
+       u32 status;
+
+       BUG_ON(!card);
+       cancel_delayed_work_sync(&card->host->start_bkops);
+
+       if (card->ext_csd.raw_bkops_status == EXT_CSD_BKOPS_LEVEL_3) {
+               do {
+                       if (timeout == 0)
+                               break;
+                       mmc_claim_host(card->host);
+                       mmc_send_status(card, &status);
+                       mmc_release_host(card->host);
+
+                       timeout--;

drivers/mmc/core/core.c int mmc_wait_for_cmd(struct mmc_host *host, struct mmc_command *cmd, int retries · line 594

Quoted 4 lines

drivers/mmc/core/core.c +4 -0

+               } while (R1_CURRENT_STATE(status) == R1_STATE_PRG);
+               if (timeout != 0)
+                       goto done;
+       }

This won't necessarily work all the time. Once BKOPS_START is issued, the card might finish GC and move to transfer state even before HPI can be sent. So just exit if the card is in transfer state already.

In this context, kdorfman's comments on "mmc:fix HPI execution sequence" makes sense.

Quoted 38 lines

drivers/mmc/core/core.c +38 -0

+
+       err = mmc_interrupt_hpi(card);
+
+done:
+       mmc_card_clr_doing_bkops(card);
+
+       return err;
+}
+EXPORT_SYMBOL(mmc_stop_bkops);
+
+int mmc_read_bkops_status(struct mmc_card *card)
+{
+       int err;
+       u8 ext_csd[512];
+
+       mmc_claim_host(card->host);
+       err = mmc_send_ext_csd(card, ext_csd);
+       mmc_release_host(card->host);
+       if (err)
+               return err;
+
+       card->ext_csd.raw_bkops_status = ext_csd[EXT_CSD_BKOPS_STATUS];
+       card->ext_csd.raw_exception_status = ext_csd[EXT_CSD_EXCEPTION_STATUS];
+
+       return 0;
+}
+EXPORT_SYMBOL(mmc_read_bkops_status);
+
+int mmc_is_exception_event(struct mmc_card *card, unsigned int value)
+{
+       int err;
+
+       err = mmc_read_bkops_status(card);
+       if (err) {
+               pr_err("%s: Didn't read bkops status : %d\n",
+                      mmc_hostname(card->host), err);
+               return 0;
+       }

drivers/mmc/core/core.c int mmc_wait_for_cmd(struct mmc_host *host, struct mmc_command *cmd, int retries · line 636

Quoted 4 lines

drivers/mmc/core/core.c +4 -0

+
+       /* In eMMC 4.41, R1_EXCEPTION_EVENT is URGENT_BKOPS */
+       if (card->ext_csd.rev == 5)
+               return 1;

Please swap the order in which you are doing this.
For eMMC4.41, we can save the mmc_read_bkops_status atleast for 4.41 card for _every_ request, which is not used.

Quoted 43 lines

drivers/mmc/core/core.c +12 -0

+
+       return (card->ext_csd.raw_exception_status & value) ? 1 : 0;
+}
+EXPORT_SYMBOL(mmc_is_exception_event);
+
+/**
 *     mmc_set_data_timeout - set the timeout for a data command
 *     @data: data phase for command
 *     @card: the MMC card associated with the data transfer

@@ -2382,6 +2542,12 @@ int mmc_pm_notify(struct notifier_block *notify_block,
       switch (mode) {
       case PM_HIBERNATION_PREPARE:
       case PM_SUSPEND_PREPARE:
+               if (host->card && mmc_card_mmc(host->card) &&
+                               mmc_card_doing_bkops(host->card)) {
+                       mmc_interrupt_hpi(host->card);
+                       mmc_card_clr_doing_bkops(host->card);
+               }
+               cancel_delayed_work_sync(&host->start_bkops);
 
               spin_lock_irqsave(&host->lock, flags);
               host->rescan_disable = 1;

drivers/mmc/core/host.c +1 -0

index 91c84c7..3b6a8e4 100644
@@ -330,6 +330,7 @@ struct mmc_host *mmc_alloc_host(int extra, struct device *dev)
       spin_lock_init(&host->lock);
       init_waitqueue_head(&host->wq);
       INIT_DELAYED_WORK(&host->detect, mmc_rescan);
+       INIT_DELAYED_WORK(&host->start_bkops, mmc_start_periodic_bkops);
 #ifdef CONFIG_PM
       host->pm_notify.notifier_call = mmc_pm_notify;
 #endif

drivers/mmc/core/mmc.c +0 -0

index 2f0e11c..275555a 100644
@@ -463,6 +463,24 @@ static int mmc_read_ext_csd(struct mmc_card *card, u8 *ext_csd)
       }
 
       if (card->ext_csd.rev >= 5) {

drivers/mmc/core/mmc.c static int mmc_read_ext_csd(struct mmc_card *card, u8 *ext_csd) · line 475

Quoted 10 lines

drivers/mmc/core/mmc.c +10 -0

+               /* check whether the eMMC card support BKOPS */
+               if (ext_csd[EXT_CSD_BKOPS_SUPPORT] & 0x1) {
+                       card->ext_csd.bkops = 1;
+                       card->ext_csd.bkops_en = ext_csd[EXT_CSD_BKOPS_EN];
+                       card->ext_csd.raw_bkops_status =
+                               ext_csd[EXT_CSD_BKOPS_STATUS];
+                       if (!card->ext_csd.bkops_en &&
+                               card->host->caps2 & MMC_CAP2_INIT_BKOPS) {
+                               err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
+                                       EXT_CSD_BKOPS_EN, 1, 0);

I am not too comfortable tying a OTP register setting to a host controller capability.
What if I had multiple instances of MMC and reuse the same HC, and each needs a different
setting ? Or the same HC used in multiple SoCs ?
A sysfs entry would be better - program the INIT when a user explicitly sets "enable_bkops" for the device
that is being used.

Quoted 186 lines

drivers/mmc/core/mmc.c +8 -0

+                               if (err)
+                                       pr_warning("%s: Enabling BKOPS failed\n",
+                                               mmc_hostname(card->host));
+                               else
+                                       card->ext_csd.bkops_en = 1;
+                       }
+               }
+
               /* check whether the eMMC card supports HPI */
               if (ext_csd[EXT_CSD_HPI_FEATURES] & 0x1) {
                       card->ext_csd.hpi = 1;

drivers/mmc/core/mmc_ops.c +4 -0

index 69370f4..bc8da17 100644
@@ -399,6 +399,10 @@ int mmc_switch(struct mmc_card *card, u8 set, u8 index, u8 value,
       if (err)
               return err;
 
+       /* No need to check card status in case of BKOPS switch*/
+       if (index == EXT_CSD_BKOPS_START)
+               return 0;
+
       /* Must check status to be sure of no errors */
       do {
               err = mmc_send_status(card, &status);

include/linux/mmc/card.h +16 -0

index d76513b..52b507d 100644
@@ -76,6 +76,9 @@ struct mmc_ext_csd {
       bool                    hpi_en;                 /* HPI enablebit */
       bool                    hpi;                    /* HPI support bit */
       unsigned int            hpi_cmd;                /* cmd used as HPI */
+       bool                    bkops;          /* background support bit */
+       bool                    bkops_en;       /* background enable bit */
+       u8                      raw_exception_status;   /* 53 */
       unsigned int            data_sector_size;       /* 512 bytes or 4KB */
       unsigned int            data_tag_unit_size;     /* DATA TAG UNIT size */
       unsigned int            boot_ro_lock;           /* ro lock support */

@@ -93,6 +96,7 @@ struct mmc_ext_csd {
       u8                      raw_sec_erase_mult;     /* 230 */
       u8                      raw_sec_feature_support;/* 231 */
       u8                      raw_trim_mult;          /* 232 */
+       u8                      raw_bkops_status;       /* 246 */
       u8                      raw_sectors[4];         /* 212 - 4 bytes */
 
       unsigned int            feature_support;

@@ -225,6 +229,9 @@ struct mmc_card {
 #define MMC_CARD_REMOVED       (1<<7)          /* card has been removed */
 #define MMC_STATE_HIGHSPEED_200        (1<<8)          /* card is in HS200 mode */
 #define MMC_STATE_SLEEP                (1<<9)          /* card is in sleep state */
+#define MMC_STATE_NEED_BKOPS   (1<<10)         /* card need to do BKOPS */
+#define MMC_STATE_DOING_BKOPS  (1<<11)         /* card is doing BKOPS */
+#define MMC_STATE_CHECK_BKOPS  (1<<12)         /* card need to check BKOPS */
       unsigned int            quirks;         /* card quirks */
 #define MMC_QUIRK_LENIENT_FN0  (1<<0)          /* allow SDIO FN0 writes outside of the VS CCCR range */
 #define MMC_QUIRK_BLKSZ_FOR_BYTE_MODE (1<<1)   /* use func->cur_blksize */

@@ -391,6 +398,9 @@ static inline void __maybe_unused remove_quirk(struct mmc_card *card, int data)
 #define mmc_card_ext_capacity(c) ((c)->state & MMC_CARD_SDXC)
 #define mmc_card_removed(c)    ((c) && ((c)->state & MMC_CARD_REMOVED))
 #define mmc_card_is_sleep(c)   ((c)->state & MMC_STATE_SLEEP)
+#define mmc_card_need_bkops(c) ((c)->state & MMC_STATE_NEED_BKOPS)
+#define mmc_card_doing_bkops(c)        ((c)->state & MMC_STATE_DOING_BKOPS)
+#define mmc_card_check_bkops(c) ((c)->state & MMC_STATE_CHECK_BKOPS)
 
 #define mmc_card_set_present(c)        ((c)->state |= MMC_STATE_PRESENT)
 #define mmc_card_set_readonly(c) ((c)->state |= MMC_STATE_READONLY)

@@ -403,7 +413,13 @@ static inline void __maybe_unused remove_quirk(struct mmc_card *card, int data)
 #define mmc_card_set_ext_capacity(c) ((c)->state |= MMC_CARD_SDXC)
 #define mmc_card_set_removed(c) ((c)->state |= MMC_CARD_REMOVED)
 #define mmc_card_set_sleep(c)  ((c)->state |= MMC_STATE_SLEEP)
+#define mmc_card_set_need_bkops(c)     ((c)->state |= MMC_STATE_NEED_BKOPS)
+#define mmc_card_set_doing_bkops(c)    ((c)->state |= MMC_STATE_DOING_BKOPS)
+#define mmc_card_set_check_bkops(c) ((c)->state |= MMC_STATE_CHECK_BKOPS)
 
+#define mmc_card_clr_need_bkops(c)     ((c)->state &= ~MMC_STATE_NEED_BKOPS)
+#define mmc_card_clr_doing_bkops(c)    ((c)->state &= ~MMC_STATE_DOING_BKOPS)
+#define mmc_card_clr_check_bkops(c) ((c)->state &= ~MMC_STATE_CHECK_BKOPS)
 #define mmc_card_clr_sleep(c)  ((c)->state &= ~MMC_STATE_SLEEP)
 /*
 * Quirk add/remove for MMC products.

include/linux/mmc/core.h +5 -0

index 1b431c7..c920250 100644
@@ -134,6 +134,9 @@ struct mmc_host;
 struct mmc_card;
 struct mmc_async_req;
 
+extern int mmc_stop_bkops(struct mmc_card *);
+extern int mmc_read_bkops_status(struct mmc_card *);
+extern int mmc_is_exception_event(struct mmc_card *, unsigned int);
 extern struct mmc_async_req *mmc_start_req(struct mmc_host *,
                                          struct mmc_async_req *, int *);
 extern int mmc_interrupt_hpi(struct mmc_card *);

@@ -163,6 +166,8 @@ extern int mmc_can_sanitize(struct mmc_card *card);
 extern int mmc_can_secure_erase_trim(struct mmc_card *card);
 extern int mmc_erase_group_aligned(struct mmc_card *card, unsigned int from,
                                  unsigned int nr);
+extern void mmc_start_periodic_bkops(struct work_struct *work);
+extern void mmc_start_bkops(struct mmc_card *card);
 extern unsigned int mmc_calc_max_discard(struct mmc_card *card);
 
 extern int mmc_set_blocklen(struct mmc_card *card, unsigned int blocklen);

include/linux/mmc/host.h +4 -0

index 0707d22..186d146 100644
@@ -238,6 +238,8 @@ struct mmc_host {
 #define MMC_CAP2_BROKEN_VOLTAGE        (1 << 7)        /* Use the broken voltage */
 #define MMC_CAP2_DETECT_ON_ERR (1 << 8)        /* On I/O err check card removal */
 #define MMC_CAP2_HC_ERASE_SZ   (1 << 9)        /* High-capacity erase size */
+#define MMC_CAP2_INIT_BKOPS    (1 << 10)       /* To enable BKOPS */
+#define MMC_CAP2_BKOPS         (1 << 11)       /* BKOPS supported */
 
       mmc_pm_flag_t           pm_caps;        /* supported pm features */
       unsigned int        power_notify_type;

@@ -320,6 +322,8 @@ struct mmc_host {
 
       unsigned int            actual_clock;   /* Actual HC clock rate */
 
+       struct delayed_work     start_bkops;    /* Periodic bkops start */
+
       unsigned long           private[0] ____cacheline_aligned;
 };
 

include/linux/mmc/mmc.h +18 -0

index d425cab..06afeb4 100644
@@ -139,6 +139,7 @@ static inline bool mmc_op_multi(u32 opcode)
 #define R1_CURRENT_STATE(x)    ((x & 0x00001E00) >> 9) /* sx, b (4 bits) */
 #define R1_READY_FOR_DATA      (1 << 8)        /* sx, a */
 #define R1_SWITCH_ERROR                (1 << 7)        /* sx, c */
+#define R1_EXCEPTION_EVENT     (1 << 6)        /* sx, a */
 #define R1_APP_CMD             (1 << 5)        /* sr, c */
 
 #define R1_STATE_IDLE  0

@@ -274,12 +275,15 @@ struct _mmc_csd {
 #define EXT_CSD_FLUSH_CACHE            32      /* W */
 #define EXT_CSD_CACHE_CTRL             33      /* R/W */
 #define EXT_CSD_POWER_OFF_NOTIFICATION 34      /* R/W */
+#define EXT_CSD_EXCEPTION_STATUS       54      /* RO */
 #define EXT_CSD_DATA_SECTOR_SIZE       61      /* R */
 #define EXT_CSD_GP_SIZE_MULT           143     /* R/W */
 #define EXT_CSD_PARTITION_ATTRIBUTE    156     /* R/W */
 #define EXT_CSD_PARTITION_SUPPORT      160     /* RO */
 #define EXT_CSD_HPI_MGMT               161     /* R/W */
 #define EXT_CSD_RST_N_FUNCTION         162     /* R/W */
+#define EXT_CSD_BKOPS_EN               163     /* R/W */
+#define EXT_CSD_BKOPS_START            164     /* W */
 #define EXT_CSD_SANITIZE_START         165     /* W */
 #define EXT_CSD_WR_REL_PARAM           166     /* RO */
 #define EXT_CSD_BOOT_WP                        173     /* R/W */

@@ -313,11 +317,13 @@ struct _mmc_csd {
 #define EXT_CSD_PWR_CL_200_360         237     /* RO */
 #define EXT_CSD_PWR_CL_DDR_52_195      238     /* RO */
 #define EXT_CSD_PWR_CL_DDR_52_360      239     /* RO */
+#define EXT_CSD_BKOPS_STATUS           246     /* RO */
 #define EXT_CSD_POWER_OFF_LONG_TIME    247     /* RO */
 #define EXT_CSD_GENERIC_CMD6_TIME      248     /* RO */
 #define EXT_CSD_CACHE_SIZE             249     /* RO, 4 bytes */
 #define EXT_CSD_TAG_UNIT_SIZE          498     /* RO */
 #define EXT_CSD_DATA_TAG_SUPPORT       499     /* RO */
+#define EXT_CSD_BKOPS_SUPPORT          502     /* RO */
 #define EXT_CSD_HPI_FEATURES           503     /* RO */
 
 /*

@@ -386,4 +392,18 @@ struct _mmc_csd {
 #define MMC_SWITCH_MODE_CLEAR_BITS     0x02    /* Clear bits which are 1 in value */
 #define MMC_SWITCH_MODE_WRITE_BYTE     0x03    /* Set target to value */
 
+/*
+ * BKOPS status level
+ */
+#define EXT_CSD_BKOPS_LEVEL_2          0x2
+#define EXT_CSD_BKOPS_LEVEL_3          0x3
+
+/*
+ * EXCEPTION_EVENT_STATUS field (eMMC4.5)
+ */
+#define EXT_CSD_URGENT_BKOPS           BIT(0)
+#define EXT_CSD_DYNCAP_NEEDED          BIT(1)
+#define EXT_CSD_SYSPOOL_EXHAUSTED      BIT(2)

include/linux/mmc/mmc.h struct _mmc_csd { · line 409

Quoted 3 lines

include/linux/mmc/mmc.h +2 -0

+#define EXT_CSD_PACKED_FAILURE         BIT(3)
+
 #endif /* LINUX_MMC_MMC_H */

Overall, my significant concern is about performance.
IIUC, There is a ext_csd query during the execution of _every_ request
- this is far too obsessive and could kill throughput.

A more pragmatic approach would be to trigger on a threshold of number of writes or discards (ex: After 1M sector writes)

This means that a predominantly read only disk, which wouldn't need any BKOPS, wouldn't have any overhead.

Let me know if my assumption is incorrect.

~Venkat.
--
To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html

Quoted 17 lines

Quoted 17 lines

drivers/mmc/core/core.c +16 -0

+static void mmc_send_bkops_cmd(struct mmc_card *card)
 
+{
+       int err;
+
+       BUG_ON(!card);
+
+       err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
+                       EXT_CSD_BKOPS_START, 1, 0);
+       if (err) {
+               pr_warning("%s: error %d starting bkops\n",
+                          mmc_hostname(card->host), err);
+               mmc_card_clr_need_bkops(card);
+               return;
+       }
+
+       mmc_card_clr_need_bkops(card);

Quoted 8 lines

drivers/mmc/core/core.c mmc_start_request(struct mmc_host *host, struct mmc_request *mrq) · line 275

Quoted 5 lines

drivers/mmc/core/core.c +5 -0

+       mmc_card_set_doing_bkops(card);
+
+}
+
+void mmc_start_periodic_bkops(struct work_struct *work)

There's nothing periodic about this function, by looking at the contents. Maybe this one should be called mmc_start_bkops ..

Well...i will checked this point..i tested with eMMC4.5 card...In my case, working this function. But in your case, didn't work nothing..i will rework to this point after debugging.

Quoted 8 lines

drivers/mmc/core/core.c mmc_start_request(struct mmc_host *host, struct mmc_request *mrq) · line 280

Quoted 7 lines

drivers/mmc/core/core.c +5 -0

+{
+       struct mmc_host *host = container_of(work, struct mmc_host,
+                       start_bkops.work);
+
+       mmc_card_set_check_bkops(host->card);

Why is this being set here. The condition should be in the caller context.

Quoted 11 lines

Quoted 11 lines

drivers/mmc/core/core.c +10 -0

+
+       mmc_claim_host(host);
+       mmc_start_bkops(host->card);
+       mmc_release_host(host);
+}
+EXPORT_SYMBOL(mmc_start_periodic_bkops);
+
+/**
+ *     mmc_start_bkops - start BKOPS for supported cards
+ *     @card: MMC card to start BKOPS

Quoted 8 lines

drivers/mmc/core/core.c mmc_start_request(struct mmc_host *host, struct mmc_request *mrq) · line 296

Quoted 6 lines

+ *

+ *     Start background operations whenever requested.
+ *     when the urgent BKOPS bit is set in a R1 command response
+ *     then background operations should be started immediately.

drivers/mmc/core/core.c +2 -0

+*/
+void mmc_start_bkops(struct mmc_card *card)

.. and this one should be called __mmc_start_bkops() ?

Sure..i will change that.

Quoted 13 lines

drivers/mmc/core/core.c mmc_start_request(struct mmc_host *host, struct mmc_request *mrq) · line 306

Quoted 11 lines

drivers/mmc/core/core.c +10 -0

+{
+       BUG_ON(!card);
+       if (!card->ext_csd.bkops_en || !(card->host->caps2 & MMC_CAP2_BKOPS))
+               return;
+
+       if (mmc_card_check_bkops(card)) {
+               mmc_card_clr_check_bkops(card);
+               if (mmc_is_exception_event(card, EXT_CSD_URGENT_BKOPS)) {
+                       if (card->ext_csd.raw_bkops_status)
+                               mmc_card_set_need_bkops(card);

This breaks abstraction. Why check ext_csd even after URGENT_BKOPS is set ?

You means that need not to check ext_csd?
Well I didn't think so, we need to check bkops-status register

Quoted 13 lines

Quoted 13 lines

drivers/mmc/core/core.c +11 -0

+               } else
+                       mmc_card_clr_need_bkops(card);
+       }
+
+       /*
+        * If card_need_bkops_flag didn't set, then do nothing just
+        * return
+        */
+       if (mmc_card_doing_bkops(card) || !mmc_card_need_bkops(card))
+               goto check_bkops;
+

Quoted 8 lines

drivers/mmc/core/core.c mmc_start_request(struct mmc_host *host, struct mmc_request *mrq) · line 321

Quoted 4 lines

drivers/mmc/core/core.c +4 -0

+       mmc_send_bkops_cmd(card);
+
+check_bkops:
+       queue_delayed_work(system_nrt_wq, &card->host->start_bkops, 5 * HZ);

IIUC, queue_delayed_work->start_bkops = mmc_start_periodic_bkops -> mmc_start_bkops -> queue_delayed_work
.. ad infinitum ?

Actually, i want to get review for this point..How did you think about?

Quoted 62 lines

Quoted 62 lines

drivers/mmc/core/core.c +36 -2

+}
+EXPORT_SYMBOL(mmc_start_bkops);
+
 static void mmc_wait_done(struct mmc_request *mrq)
 {
       complete(&mrq->completion);

@@ -348,8 +425,10 @@ struct mmc_async_req *mmc_start_req(struct mmc_host *host,
       struct mmc_async_req *data = host->areq;
 
       /* Prepare a new request */
-       if (areq)
+       if (areq) {
+               cancel_delayed_work_sync(&host->start_bkops);
               mmc_pre_req(host, areq->mrq, !host->areq);
+       }
 
       if (host->areq) {
               mmc_wait_for_req_done(host, host->areq->mrq);

@@ -359,8 +438,11 @@ struct mmc_async_req *mmc_start_req(struct mmc_host *host,
       if (!err && areq)
               start_err = __mmc_start_req(host, areq->mrq);
 
-       if (host->areq)
+       if (host->areq) {
               mmc_post_req(host, host->areq->mrq, 0);
+               if (!areq && host->areq && mmc_card_mmc(host->card))
+                       mmc_start_bkops(host->card);
+       }
 
        /* Cancel a prepared request if it was not started. */
       if ((err || start_err) && areq)

@@ -480,6 +562,84 @@ int mmc_wait_for_cmd(struct mmc_host *host, struct mmc_command *cmd, int retries
 EXPORT_SYMBOL(mmc_wait_for_cmd);
 
 /**
+ *     mmc_stop_bkops - stop ongoing BKOPS
+ *     @card: MMC card to check BKOPS
+ *
+ *     Send HPI command to interrupt ongoing background operations,
+ *     to allow rapid servicing of foreground operations,e.g. read/
+ *     writes. Wait until the card comes out of the programming state
+ *     to avoid errors in servicing read/write requests.
+ */
+int mmc_stop_bkops(struct mmc_card *card)
+{
+       int err = 0;
+       unsigned int timeout = 0x10000;
+       u32 status;
+
+       BUG_ON(!card);
+       cancel_delayed_work_sync(&card->host->start_bkops);
+
+       if (card->ext_csd.raw_bkops_status == EXT_CSD_BKOPS_LEVEL_3) {
+               do {
+                       if (timeout == 0)
+                               break;
+                       mmc_claim_host(card->host);
+                       mmc_send_status(card, &status);
+                       mmc_release_host(card->host);
+
+                       timeout--;

Quoted 8 lines

drivers/mmc/core/core.c int mmc_wait_for_cmd(struct mmc_host *host, struct mmc_command *cmd, int retries · line 594

Quoted 4 lines

drivers/mmc/core/core.c +4 -0

+               } while (R1_CURRENT_STATE(status) == R1_STATE_PRG);
+               if (timeout != 0)
+                       goto done;
+       }

This won't necessarily work all the time. Once BKOPS_START is issued, the card might finish GC and move to transfer state even before HPI can be sent. So just exit if the card is in transfer state already.

Right..But if didn't wait for prog-done, we can issue the HPI. (If didn't use Busy waiting flag)

Quoted 42 lines

In this context, kdorfman's comments on "mmc:fix HPI execution sequence" makes sense.

Quoted 38 lines

drivers/mmc/core/core.c +38 -0

+
+       err = mmc_interrupt_hpi(card);
+
+done:
+       mmc_card_clr_doing_bkops(card);
+
+       return err;
+}
+EXPORT_SYMBOL(mmc_stop_bkops);
+
+int mmc_read_bkops_status(struct mmc_card *card)
+{
+       int err;
+       u8 ext_csd[512];
+
+       mmc_claim_host(card->host);
+       err = mmc_send_ext_csd(card, ext_csd);
+       mmc_release_host(card->host);
+       if (err)
+               return err;
+
+       card->ext_csd.raw_bkops_status = ext_csd[EXT_CSD_BKOPS_STATUS];
+       card->ext_csd.raw_exception_status = ext_csd[EXT_CSD_EXCEPTION_STATUS];
+
+       return 0;
+}
+EXPORT_SYMBOL(mmc_read_bkops_status);
+
+int mmc_is_exception_event(struct mmc_card *card, unsigned int value)
+{
+       int err;
+
+       err = mmc_read_bkops_status(card);
+       if (err) {
+               pr_err("%s: Didn't read bkops status : %d\n",
+                      mmc_hostname(card->host), err);
+               return 0;
+       }

Quoted 8 lines

drivers/mmc/core/core.c int mmc_wait_for_cmd(struct mmc_host *host, struct mmc_command *cmd, int retries · line 636

Quoted 4 lines

drivers/mmc/core/core.c +4 -0

+
+       /* In eMMC 4.41, R1_EXCEPTION_EVENT is URGENT_BKOPS */
+       if (card->ext_csd.rev == 5)
+               return 1;

Please swap the order in which you are doing this.
For eMMC4.41, we can save the mmc_read_bkops_status atleast for 4.41 card for _every_ request, which is not used.

If card is eMMC4.41, how did you check bkops-status? In eMCM4.41, also check the bkops-status level.

Quoted 54 lines

Quoted 43 lines

drivers/mmc/core/core.c +12 -0

+
+       return (card->ext_csd.raw_exception_status & value) ? 1 : 0;
+}
+EXPORT_SYMBOL(mmc_is_exception_event);
+
+/**
 *     mmc_set_data_timeout - set the timeout for a data command
 *     @data: data phase for command
 *     @card: the MMC card associated with the data transfer

@@ -2382,6 +2542,12 @@ int mmc_pm_notify(struct notifier_block *notify_block,
       switch (mode) {
       case PM_HIBERNATION_PREPARE:
       case PM_SUSPEND_PREPARE:
+               if (host->card && mmc_card_mmc(host->card) &&
+                               mmc_card_doing_bkops(host->card)) {
+                       mmc_interrupt_hpi(host->card);
+                       mmc_card_clr_doing_bkops(host->card);
+               }
+               cancel_delayed_work_sync(&host->start_bkops);
 
               spin_lock_irqsave(&host->lock, flags);
               host->rescan_disable = 1;

drivers/mmc/core/host.c +1 -0

index 91c84c7..3b6a8e4 100644
@@ -330,6 +330,7 @@ struct mmc_host *mmc_alloc_host(int extra, struct device *dev)
       spin_lock_init(&host->lock);
       init_waitqueue_head(&host->wq);
       INIT_DELAYED_WORK(&host->detect, mmc_rescan);
+       INIT_DELAYED_WORK(&host->start_bkops, mmc_start_periodic_bkops);
 #ifdef CONFIG_PM
       host->pm_notify.notifier_call = mmc_pm_notify;
 #endif

drivers/mmc/core/mmc.c +0 -0

index 2f0e11c..275555a 100644
@@ -463,6 +463,24 @@ static int mmc_read_ext_csd(struct mmc_card *card, u8 *ext_csd)
       }
 
       if (card->ext_csd.rev >= 5) {

drivers/mmc/core/mmc.c static int mmc_read_ext_csd(struct mmc_card *card, u8 *ext_csd) · line 475

Quoted 10 lines

drivers/mmc/core/mmc.c +10 -0

+               /* check whether the eMMC card support BKOPS */
+               if (ext_csd[EXT_CSD_BKOPS_SUPPORT] & 0x1) {
+                       card->ext_csd.bkops = 1;
+                       card->ext_csd.bkops_en = ext_csd[EXT_CSD_BKOPS_EN];
+                       card->ext_csd.raw_bkops_status =
+                               ext_csd[EXT_CSD_BKOPS_STATUS];
+                       if (!card->ext_csd.bkops_en &&
+                               card->host->caps2 & MMC_CAP2_INIT_BKOPS) {
+                               err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
+                                       EXT_CSD_BKOPS_EN, 1, 0);

Quoted 8 lines

I am not too comfortable tying a OTP register setting to a host controller capability.
What if I had multiple instances of MMC and reuse the same HC, and each needs a different
setting ? Or the same HC used in multiple SoCs ?
A sysfs entry would be better - program the INIT when a user explicitly sets "enable_bkops" for the device
that is being used.

Actually, at first time i didn't consider whether bkops is enabled or not. Some card can be disabled for bkops enable bit.
If INIT_BKOPS is set, user didn't consider whether bkops is enabled or not. because that's set to enable.
Right, this is used sysfs..but I think it's problem what is prefrence..

Quoted 186 lines

Quoted 186 lines

drivers/mmc/core/mmc.c +8 -0

+                               if (err)
+                                       pr_warning("%s: Enabling BKOPS failed\n",
+                                               mmc_hostname(card->host));
+                               else
+                                       card->ext_csd.bkops_en = 1;
+                       }
+               }
+
               /* check whether the eMMC card supports HPI */
               if (ext_csd[EXT_CSD_HPI_FEATURES] & 0x1) {
                       card->ext_csd.hpi = 1;

drivers/mmc/core/mmc_ops.c +4 -0

index 69370f4..bc8da17 100644
@@ -399,6 +399,10 @@ int mmc_switch(struct mmc_card *card, u8 set, u8 index, u8 value,
       if (err)
               return err;
 
+       /* No need to check card status in case of BKOPS switch*/
+       if (index == EXT_CSD_BKOPS_START)
+               return 0;
+
       /* Must check status to be sure of no errors */
       do {
               err = mmc_send_status(card, &status);

include/linux/mmc/card.h +16 -0

index d76513b..52b507d 100644
@@ -76,6 +76,9 @@ struct mmc_ext_csd {
       bool                    hpi_en;                 /* HPI enablebit */
       bool                    hpi;                    /* HPI support bit */
       unsigned int            hpi_cmd;                /* cmd used as HPI */
+       bool                    bkops;          /* background support bit */
+       bool                    bkops_en;       /* background enable bit */
+       u8                      raw_exception_status;   /* 53 */
       unsigned int            data_sector_size;       /* 512 bytes or 4KB */
       unsigned int            data_tag_unit_size;     /* DATA TAG UNIT size */
       unsigned int            boot_ro_lock;           /* ro lock support */

@@ -93,6 +96,7 @@ struct mmc_ext_csd {
       u8                      raw_sec_erase_mult;     /* 230 */
       u8                      raw_sec_feature_support;/* 231 */
       u8                      raw_trim_mult;          /* 232 */
+       u8                      raw_bkops_status;       /* 246 */
       u8                      raw_sectors[4];         /* 212 - 4 bytes */
 
       unsigned int            feature_support;

@@ -225,6 +229,9 @@ struct mmc_card {
 #define MMC_CARD_REMOVED       (1<<7)          /* card has been removed */
 #define MMC_STATE_HIGHSPEED_200        (1<<8)          /* card is in HS200 mode */
 #define MMC_STATE_SLEEP                (1<<9)          /* card is in sleep state */
+#define MMC_STATE_NEED_BKOPS   (1<<10)         /* card need to do BKOPS */
+#define MMC_STATE_DOING_BKOPS  (1<<11)         /* card is doing BKOPS */
+#define MMC_STATE_CHECK_BKOPS  (1<<12)         /* card need to check BKOPS */
       unsigned int            quirks;         /* card quirks */
 #define MMC_QUIRK_LENIENT_FN0  (1<<0)          /* allow SDIO FN0 writes outside of the VS CCCR range */
 #define MMC_QUIRK_BLKSZ_FOR_BYTE_MODE (1<<1)   /* use func->cur_blksize */

@@ -391,6 +398,9 @@ static inline void __maybe_unused remove_quirk(struct mmc_card *card, int data)
 #define mmc_card_ext_capacity(c) ((c)->state & MMC_CARD_SDXC)
 #define mmc_card_removed(c)    ((c) && ((c)->state & MMC_CARD_REMOVED))
 #define mmc_card_is_sleep(c)   ((c)->state & MMC_STATE_SLEEP)
+#define mmc_card_need_bkops(c) ((c)->state & MMC_STATE_NEED_BKOPS)
+#define mmc_card_doing_bkops(c)        ((c)->state & MMC_STATE_DOING_BKOPS)
+#define mmc_card_check_bkops(c) ((c)->state & MMC_STATE_CHECK_BKOPS)
 
 #define mmc_card_set_present(c)        ((c)->state |= MMC_STATE_PRESENT)
 #define mmc_card_set_readonly(c) ((c)->state |= MMC_STATE_READONLY)

@@ -403,7 +413,13 @@ static inline void __maybe_unused remove_quirk(struct mmc_card *card, int data)
 #define mmc_card_set_ext_capacity(c) ((c)->state |= MMC_CARD_SDXC)
 #define mmc_card_set_removed(c) ((c)->state |= MMC_CARD_REMOVED)
 #define mmc_card_set_sleep(c)  ((c)->state |= MMC_STATE_SLEEP)
+#define mmc_card_set_need_bkops(c)     ((c)->state |= MMC_STATE_NEED_BKOPS)
+#define mmc_card_set_doing_bkops(c)    ((c)->state |= MMC_STATE_DOING_BKOPS)
+#define mmc_card_set_check_bkops(c) ((c)->state |= MMC_STATE_CHECK_BKOPS)
 
+#define mmc_card_clr_need_bkops(c)     ((c)->state &= ~MMC_STATE_NEED_BKOPS)
+#define mmc_card_clr_doing_bkops(c)    ((c)->state &= ~MMC_STATE_DOING_BKOPS)
+#define mmc_card_clr_check_bkops(c) ((c)->state &= ~MMC_STATE_CHECK_BKOPS)
 #define mmc_card_clr_sleep(c)  ((c)->state &= ~MMC_STATE_SLEEP)
 /*
 * Quirk add/remove for MMC products.

include/linux/mmc/core.h +5 -0

index 1b431c7..c920250 100644
@@ -134,6 +134,9 @@ struct mmc_host;
 struct mmc_card;
 struct mmc_async_req;
 
+extern int mmc_stop_bkops(struct mmc_card *);
+extern int mmc_read_bkops_status(struct mmc_card *);
+extern int mmc_is_exception_event(struct mmc_card *, unsigned int);
 extern struct mmc_async_req *mmc_start_req(struct mmc_host *,
                                          struct mmc_async_req *, int *);
 extern int mmc_interrupt_hpi(struct mmc_card *);

@@ -163,6 +166,8 @@ extern int mmc_can_sanitize(struct mmc_card *card);
 extern int mmc_can_secure_erase_trim(struct mmc_card *card);
 extern int mmc_erase_group_aligned(struct mmc_card *card, unsigned int from,
                                  unsigned int nr);
+extern void mmc_start_periodic_bkops(struct work_struct *work);
+extern void mmc_start_bkops(struct mmc_card *card);
 extern unsigned int mmc_calc_max_discard(struct mmc_card *card);
 
 extern int mmc_set_blocklen(struct mmc_card *card, unsigned int blocklen);

include/linux/mmc/host.h +4 -0

index 0707d22..186d146 100644
@@ -238,6 +238,8 @@ struct mmc_host {
 #define MMC_CAP2_BROKEN_VOLTAGE        (1 << 7)        /* Use the broken voltage */
 #define MMC_CAP2_DETECT_ON_ERR (1 << 8)        /* On I/O err check card removal */
 #define MMC_CAP2_HC_ERASE_SZ   (1 << 9)        /* High-capacity erase size */
+#define MMC_CAP2_INIT_BKOPS    (1 << 10)       /* To enable BKOPS */
+#define MMC_CAP2_BKOPS         (1 << 11)       /* BKOPS supported */
 
       mmc_pm_flag_t           pm_caps;        /* supported pm features */
       unsigned int        power_notify_type;

@@ -320,6 +322,8 @@ struct mmc_host {
 
       unsigned int            actual_clock;   /* Actual HC clock rate */
 
+       struct delayed_work     start_bkops;    /* Periodic bkops start */
+
       unsigned long           private[0] ____cacheline_aligned;
 };
 

include/linux/mmc/mmc.h +18 -0

index d425cab..06afeb4 100644
@@ -139,6 +139,7 @@ static inline bool mmc_op_multi(u32 opcode)
 #define R1_CURRENT_STATE(x)    ((x & 0x00001E00) >> 9) /* sx, b (4 bits) */
 #define R1_READY_FOR_DATA      (1 << 8)        /* sx, a */
 #define R1_SWITCH_ERROR                (1 << 7)        /* sx, c */
+#define R1_EXCEPTION_EVENT     (1 << 6)        /* sx, a */
 #define R1_APP_CMD             (1 << 5)        /* sr, c */
 
 #define R1_STATE_IDLE  0

@@ -274,12 +275,15 @@ struct _mmc_csd {
 #define EXT_CSD_FLUSH_CACHE            32      /* W */
 #define EXT_CSD_CACHE_CTRL             33      /* R/W */
 #define EXT_CSD_POWER_OFF_NOTIFICATION 34      /* R/W */
+#define EXT_CSD_EXCEPTION_STATUS       54      /* RO */
 #define EXT_CSD_DATA_SECTOR_SIZE       61      /* R */
 #define EXT_CSD_GP_SIZE_MULT           143     /* R/W */
 #define EXT_CSD_PARTITION_ATTRIBUTE    156     /* R/W */
 #define EXT_CSD_PARTITION_SUPPORT      160     /* RO */
 #define EXT_CSD_HPI_MGMT               161     /* R/W */
 #define EXT_CSD_RST_N_FUNCTION         162     /* R/W */
+#define EXT_CSD_BKOPS_EN               163     /* R/W */
+#define EXT_CSD_BKOPS_START            164     /* W */
 #define EXT_CSD_SANITIZE_START         165     /* W */
 #define EXT_CSD_WR_REL_PARAM           166     /* RO */
 #define EXT_CSD_BOOT_WP                        173     /* R/W */

@@ -313,11 +317,13 @@ struct _mmc_csd {
 #define EXT_CSD_PWR_CL_200_360         237     /* RO */
 #define EXT_CSD_PWR_CL_DDR_52_195      238     /* RO */
 #define EXT_CSD_PWR_CL_DDR_52_360      239     /* RO */
+#define EXT_CSD_BKOPS_STATUS           246     /* RO */
 #define EXT_CSD_POWER_OFF_LONG_TIME    247     /* RO */
 #define EXT_CSD_GENERIC_CMD6_TIME      248     /* RO */
 #define EXT_CSD_CACHE_SIZE             249     /* RO, 4 bytes */
 #define EXT_CSD_TAG_UNIT_SIZE          498     /* RO */
 #define EXT_CSD_DATA_TAG_SUPPORT       499     /* RO */
+#define EXT_CSD_BKOPS_SUPPORT          502     /* RO */
 #define EXT_CSD_HPI_FEATURES           503     /* RO */
 
 /*

@@ -386,4 +392,18 @@ struct _mmc_csd {
 #define MMC_SWITCH_MODE_CLEAR_BITS     0x02    /* Clear bits which are 1 in value */
 #define MMC_SWITCH_MODE_WRITE_BYTE     0x03    /* Set target to value */
 
+/*
+ * BKOPS status level
+ */
+#define EXT_CSD_BKOPS_LEVEL_2          0x2
+#define EXT_CSD_BKOPS_LEVEL_3          0x3
+
+/*
+ * EXCEPTION_EVENT_STATUS field (eMMC4.5)
+ */
+#define EXT_CSD_URGENT_BKOPS           BIT(0)
+#define EXT_CSD_DYNCAP_NEEDED          BIT(1)
+#define EXT_CSD_SYSPOOL_EXHAUSTED      BIT(2)

Quoted 8 lines

include/linux/mmc/mmc.h struct _mmc_csd { · line 409

Quoted 3 lines

include/linux/mmc/mmc.h +2 -0

+#define EXT_CSD_PACKED_FAILURE         BIT(3)
+
 #endif /* LINUX_MMC_MMC_H */

Overall, my significant concern is about performance.
IIUC, There is a ext_csd query during the execution of _every_ request
- this is far too obsessive and could kill throughput.

I didn't find the performance issue. didn't _every_ request..only check to set bkops_need_check.

Quoted 2 lines

A more pragmatic approach would be to trigger on a threshold of number of writes or discards (ex: After 1M sector writes)

I will try to this approach.

Quoted 4 lines

This means that a predominantly read only disk, which wouldn't need any BKOPS, wouldn't have any overhead.

Let me know if my assumption is incorrect.

Thanks for reviwe.

Best Regards,
Jaehoon Chung

Quoted 7 lines

~Venkat.
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Enable eMMC background operations (BKOPS) feature.

If URGENT_BKOPS is set after a response, note that BKOPS are required. After all I/O requests are finished, run BKOPS if required. Should read/write operations be requested during BKOPS, first issue HPI to interrupt the ongoing BKOPS and then service the request.
If BKOPS-STATUS is upper than LEVEL2, need to check until clear the BKOPS-STATUS vaule.

If you want to enable this feature, set MMC_CAP2_BKOPS. And if you want to set the BKOPS_EN bit in ext_csd register, use the MMC_CAP2_INIT_BKOPS.

When BKOPS_STATUS is Level-3, if we're waiting for done, it spent 60~80sec. So Added timeout value. if timeout value is set to 0, send hpi command.

Signed-off-by Jaehoon Chung<[email protected]>

Signed-off-by Kyungmin Park<[email protected]>

---
Changelog V8:
- Remove host->lock spin lock reviewed by Adrian
- Support periodic start bkops
- when bkops_status is level-3, if timeout is set to 0, send hpi.
- Move the start-bkops point
Changelog V7:
- Use HPI command when issued URGENT_BKOPS
- Recheck until clearing the bkops-status bit.
Changelog V6:
- Add the flag of check-bkops-status.
(For fixing async_req problem)
- Add the capability for MMC_CAP2_INIT_BKOPS.
(When unset the bkops_en bit in ext_csd register)
- modify the wrong condition.
Changelog V5:
- Rebase based on the latest mmc-next.
- modify codes based-on Chris's comment
Changelog V4:
- Add mmc_read_bkops_status
- When URGENT_BKOPS(level2-3), didn't use HPI command.
- In mmc_switch(), use R1B/R1 according to level.
Changelog V3:
- move the bkops setting's location in mmc_blk_issue_rw_rq
- modify condition checking
- bkops_en is assigned ext_csd[EXT_CSD_BKOPS_EN] instead of "1"
- remove the unused code
- change pr_debug instead of pr_warn in mmc_send_hpi_cmd
- Add the Future consideration suggested by Per
Changelog V2:
- Use EXCEPTION_STATUS instead of URGENT_BKOPS
- Add function to check Exception_status(for eMMC4.5)

---
  drivers/mmc/card/queue.c   |    2 +
  drivers/mmc/core/core.c    |  170 +++++++++++++++++++++++++++++++++++++++++++-
  drivers/mmc/core/host.c    |    1 +
  drivers/mmc/core/mmc.c     |   18 +++++
  drivers/mmc/core/mmc_ops.c |    4 +
  include/linux/mmc/card.h   |   16 ++++
  include/linux/mmc/core.h   |    5 ++
  include/linux/mmc/host.h   |    4 +
  include/linux/mmc/mmc.h    |   20 +++++
  9 files changed, 238 insertions(+), 2 deletions(-)

drivers/mmc/card/queue.c +0 -0

index e360a97..e4a2cde 100644

drivers/mmc/card/queue.c +0 -0

  			set_current_state(TASK_RUNNING);
  			mq->issue_fn(mq, req);
  		} else {

drivers/mmc/core/core.c +0 -0

index 0b6141d..91a03d5 100644

drivers/mmc/core/core.c +39 -0

+}
+
+void mmc_start_periodic_bkops(struct work_struct *work)
+{
+	struct mmc_host *host = container_of(work, struct mmc_host,
+			start_bkops.work);
+
+	mmc_card_set_check_bkops(host->card);
+
+	mmc_claim_host(host);
+	mmc_start_bkops(host->card);
+	mmc_release_host(host);
+}
+EXPORT_SYMBOL(mmc_start_periodic_bkops);
+
+/**
+ *	mmc_start_bkops - start BKOPS for supported cards
+ *	@card: MMC card to start BKOPS
+ *
+ *	Start background operations whenever requested.
+ *	when the urgent BKOPS bit is set in a R1 command response
+ *	then background operations should be started immediately.
+*/
+void mmc_start_bkops(struct mmc_card *card)
+{
+	BUG_ON(!card);
+	if (!card->ext_csd.bkops_en || !(card->host->caps2&  MMC_CAP2_BKOPS))
+		return;
+
+	if (mmc_card_check_bkops(card)) {
+		mmc_card_clr_check_bkops(card);
+		if (mmc_is_exception_event(card, EXT_CSD_URGENT_BKOPS)) {
+			if (card->ext_csd.raw_bkops_status)
+				mmc_card_set_need_bkops(card);
+		} else
+			mmc_card_clr_need_bkops(card);
+	}
+
+	/*

drivers/mmc/core/core.c +12 -2

+}
+EXPORT_SYMBOL(mmc_start_bkops);
+
  static void mmc_wait_done(struct mmc_request *mrq)
  {
  	complete(&mrq->completion);

@@ -348,8 +425,10 @@ struct mmc_async_req *mmc_start_req(struct mmc_host *host,
  	struct mmc_async_req *data = host->areq;
 
  	/* Prepare a new request */
-	if (areq)
+	if (areq) {
+		cancel_delayed_work_sync(&host->start_bkops);
  		mmc_pre_req(host, areq->mrq, !host->areq);
+	}
 
  	if (host->areq) {
  		mmc_wait_for_req_done(host, host->areq->mrq);

@@ -359,8 +438,11 @@ struct mmc_async_req *mmc_start_req(struct mmc_host *host,
  	if (!err&&  areq)
  		start_err = __mmc_start_req(host, areq->mrq);
 
-	if (host->areq)
+	if (host->areq) {
  		mmc_post_req(host, host->areq->mrq, 0);
+		if (!areq&&  host->areq&&  mmc_card_mmc(host->card))
+			mmc_start_bkops(host->card);
+	}
 
  	 /* Cancel a prepared request if it was not started. */
  	if ((err || start_err)&&  areq)

@@ -480,6 +562,84 @@ int mmc_wait_for_cmd(struct mmc_host *host, struct mmc_command *cmd, int retries
  EXPORT_SYMBOL(mmc_wait_for_cmd);
 
  /**
+ *	mmc_stop_bkops - stop ongoing BKOPS
+ *	@card: MMC card to check BKOPS

drivers/mmc/core/core.c +13 -0

+	u32 status;
+
+	BUG_ON(!card);
+	cancel_delayed_work_sync(&card->host->start_bkops);
+
+	if (card->ext_csd.raw_bkops_status == EXT_CSD_BKOPS_LEVEL_3) {
+		do {
+			if (timeout == 0)
+				break;
+			mmc_claim_host(card->host);
+			mmc_send_status(card,&status);
+			mmc_release_host(card->host);
+

drivers/mmc/core/core.c +49 -0

+
+	return err;
+}
+EXPORT_SYMBOL(mmc_stop_bkops);
+
+int mmc_read_bkops_status(struct mmc_card *card)
+{
+	int err;
+	u8 ext_csd[512];
+
+	mmc_claim_host(card->host);
+	err = mmc_send_ext_csd(card, ext_csd);
+	mmc_release_host(card->host);
+	if (err)
+		return err;
+
+	card->ext_csd.raw_bkops_status = ext_csd[EXT_CSD_BKOPS_STATUS];
+	card->ext_csd.raw_exception_status = ext_csd[EXT_CSD_EXCEPTION_STATUS];
+
+	return 0;
+}
+EXPORT_SYMBOL(mmc_read_bkops_status);
+
+int mmc_is_exception_event(struct mmc_card *card, unsigned int value)
+{
+	int err;
+
+	err = mmc_read_bkops_status(card);
+	if (err) {
+		pr_err("%s: Didn't read bkops status : %d\n",
+		       mmc_hostname(card->host), err);
+		return 0;
+	}
+
+	/* In eMMC 4.41, R1_EXCEPTION_EVENT is URGENT_BKOPS */
+	if (card->ext_csd.rev == 5)
+		return 1;
+
+	return (card->ext_csd.raw_exception_status&  value) ? 1 : 0;
+}
+EXPORT_SYMBOL(mmc_is_exception_event);
+
+/**
   *	mmc_set_data_timeout - set the timeout for a data command
   *	@data: data phase for command
   *	@card: the MMC card associated with the data transfer

@@ -2382,6 +2542,12 @@ int mmc_pm_notify(struct notifier_block *notify_block,
  	switch (mode) {
  	case PM_HIBERNATION_PREPARE:
  	case PM_SUSPEND_PREPARE:
+		if (host->card&&  mmc_card_mmc(host->card)&&
+				mmc_card_doing_bkops(host->card)) {
+			mmc_interrupt_hpi(host->card);
+			mmc_card_clr_doing_bkops(host->card);
+		}
+		cancel_delayed_work_sync(&host->start_bkops);
 
  		spin_lock_irqsave(&host->lock, flags);
  		host->rescan_disable = 1;

drivers/mmc/core/host.c +1 -0

index 91c84c7..3b6a8e4 100644
@@ -330,6 +330,7 @@ struct mmc_host *mmc_alloc_host(int extra, struct device *dev)
  	spin_lock_init(&host->lock);
  	init_waitqueue_head(&host->wq);
  	INIT_DELAYED_WORK(&host->detect, mmc_rescan);
+	INIT_DELAYED_WORK(&host->start_bkops, mmc_start_periodic_bkops);
  #ifdef CONFIG_PM
  	host->pm_notify.notifier_call = mmc_pm_notify;
  #endif

drivers/mmc/core/mmc.c +18 -0

index 2f0e11c..275555a 100644
@@ -463,6 +463,24 @@ static int mmc_read_ext_csd(struct mmc_card *card, u8 *ext_csd)
  	}
 
  	if (card->ext_csd.rev>= 5) {
+		/* check whether the eMMC card support BKOPS */
+		if (ext_csd[EXT_CSD_BKOPS_SUPPORT]&  0x1) {
+			card->ext_csd.bkops = 1;
+			card->ext_csd.bkops_en = ext_csd[EXT_CSD_BKOPS_EN];
+			card->ext_csd.raw_bkops_status =
+				ext_csd[EXT_CSD_BKOPS_STATUS];
+			if (!card->ext_csd.bkops_en&&
+				card->host->caps2&  MMC_CAP2_INIT_BKOPS) {
+				err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
+					EXT_CSD_BKOPS_EN, 1, 0);
+				if (err)
+					pr_warning("%s: Enabling BKOPS failed\n",
+						mmc_hostname(card->host));
+				else
+					card->ext_csd.bkops_en = 1;
+			}
+		}
+
  		/* check whether the eMMC card supports HPI */
  		if (ext_csd[EXT_CSD_HPI_FEATURES]&  0x1) {
  			card->ext_csd.hpi = 1;

drivers/mmc/core/mmc_ops.c +4 -0

index 69370f4..bc8da17 100644
@@ -399,6 +399,10 @@ int mmc_switch(struct mmc_card *card, u8 set, u8 index, u8 value,
  	if (err)
  		return err;
 
+	/* No need to check card status in case of BKOPS switch*/
+	if (index == EXT_CSD_BKOPS_START)
+		return 0;
+
  	/* Must check status to be sure of no errors */
  	do {
  		err = mmc_send_status(card,&status);

include/linux/mmc/card.h +16 -0

index d76513b..52b507d 100644
@@ -76,6 +76,9 @@ struct mmc_ext_csd {
  	bool			hpi_en;			/* HPI enablebit */
  	bool			hpi;			/* HPI support bit */
  	unsigned int		hpi_cmd;		/* cmd used as HPI */
+	bool			bkops;		/* background support bit */
+	bool			bkops_en;	/* background enable bit */
+	u8			raw_exception_status;	/* 53 */
  	unsigned int            data_sector_size;       /* 512 bytes or 4KB */
  	unsigned int            data_tag_unit_size;     /* DATA TAG UNIT size */
  	unsigned int		boot_ro_lock;		/* ro lock support */

@@ -93,6 +96,7 @@ struct mmc_ext_csd {
  	u8			raw_sec_erase_mult;	/* 230 */
  	u8			raw_sec_feature_support;/* 231 */
  	u8			raw_trim_mult;		/* 232 */
+	u8			raw_bkops_status;	/* 246 */
  	u8			raw_sectors[4];		/* 212 - 4 bytes */
 
  	unsigned int            feature_support;

@@ -225,6 +229,9 @@ struct mmc_card {
  #define MMC_CARD_REMOVED	(1<<7)		/* card has been removed */
  #define MMC_STATE_HIGHSPEED_200	(1<<8)		/* card is in HS200 mode */
  #define MMC_STATE_SLEEP		(1<<9)		/* card is in sleep state */
+#define MMC_STATE_NEED_BKOPS	(1<<10)		/* card need to do BKOPS */
+#define MMC_STATE_DOING_BKOPS	(1<<11)		/* card is doing BKOPS */
+#define MMC_STATE_CHECK_BKOPS	(1<<12)		/* card need to check BKOPS */
  	unsigned int		quirks; 	/* card quirks */
  #define MMC_QUIRK_LENIENT_FN0	(1<<0)		/* allow SDIO FN0 writes outside of the VS CCCR range */
  #define MMC_QUIRK_BLKSZ_FOR_BYTE_MODE (1<<1)	/* use func->cur_blksize */

@@ -391,6 +398,9 @@ static inline void __maybe_unused remove_quirk(struct mmc_card *card, int data)
  #define mmc_card_ext_capacity(c) ((c)->state&  MMC_CARD_SDXC)
  #define mmc_card_removed(c)	((c)&&  ((c)->state&  MMC_CARD_REMOVED))
  #define mmc_card_is_sleep(c)	((c)->state&  MMC_STATE_SLEEP)
+#define mmc_card_need_bkops(c)	((c)->state&  MMC_STATE_NEED_BKOPS)
+#define mmc_card_doing_bkops(c)	((c)->state&  MMC_STATE_DOING_BKOPS)
+#define mmc_card_check_bkops(c) ((c)->state&  MMC_STATE_CHECK_BKOPS)
 
  #define mmc_card_set_present(c)	((c)->state |= MMC_STATE_PRESENT)
  #define mmc_card_set_readonly(c) ((c)->state |= MMC_STATE_READONLY)

@@ -403,7 +413,13 @@ static inline void __maybe_unused remove_quirk(struct mmc_card *card, int data)
  #define mmc_card_set_ext_capacity(c) ((c)->state |= MMC_CARD_SDXC)
  #define mmc_card_set_removed(c) ((c)->state |= MMC_CARD_REMOVED)
  #define mmc_card_set_sleep(c)	((c)->state |= MMC_STATE_SLEEP)
+#define mmc_card_set_need_bkops(c)	((c)->state |= MMC_STATE_NEED_BKOPS)
+#define mmc_card_set_doing_bkops(c)	((c)->state |= MMC_STATE_DOING_BKOPS)
+#define mmc_card_set_check_bkops(c) ((c)->state |= MMC_STATE_CHECK_BKOPS)
 
+#define mmc_card_clr_need_bkops(c)	((c)->state&= ~MMC_STATE_NEED_BKOPS)
+#define mmc_card_clr_doing_bkops(c)	((c)->state&= ~MMC_STATE_DOING_BKOPS)
+#define mmc_card_clr_check_bkops(c) ((c)->state&= ~MMC_STATE_CHECK_BKOPS)
  #define mmc_card_clr_sleep(c)	((c)->state&= ~MMC_STATE_SLEEP)
  /*
   * Quirk add/remove for MMC products.

include/linux/mmc/core.h +5 -0

index 1b431c7..c920250 100644
@@ -134,6 +134,9 @@ struct mmc_host;
  struct mmc_card;
  struct mmc_async_req;
 
+extern int mmc_stop_bkops(struct mmc_card *);
+extern int mmc_read_bkops_status(struct mmc_card *);
+extern int mmc_is_exception_event(struct mmc_card *, unsigned int);
  extern struct mmc_async_req *mmc_start_req(struct mmc_host *,
  					   struct mmc_async_req *, int *);
  extern int mmc_interrupt_hpi(struct mmc_card *);

@@ -163,6 +166,8 @@ extern int mmc_can_sanitize(struct mmc_card *card);
  extern int mmc_can_secure_erase_trim(struct mmc_card *card);
  extern int mmc_erase_group_aligned(struct mmc_card *card, unsigned int from,
  				   unsigned int nr);
+extern void mmc_start_periodic_bkops(struct work_struct *work);
+extern void mmc_start_bkops(struct mmc_card *card);
  extern unsigned int mmc_calc_max_discard(struct mmc_card *card);
 
  extern int mmc_set_blocklen(struct mmc_card *card, unsigned int blocklen);

include/linux/mmc/host.h +4 -0

index 0707d22..186d146 100644
@@ -238,6 +238,8 @@ struct mmc_host {
  #define MMC_CAP2_BROKEN_VOLTAGE	(1<<  7)	/* Use the broken voltage */
  #define MMC_CAP2_DETECT_ON_ERR	(1<<  8)	/* On I/O err check card removal */
  #define MMC_CAP2_HC_ERASE_SZ	(1<<  9)	/* High-capacity erase size */
+#define MMC_CAP2_INIT_BKOPS	(1<<  10)	/* To enable BKOPS */
+#define MMC_CAP2_BKOPS		(1<<  11)	/* BKOPS supported */
 
  	mmc_pm_flag_t		pm_caps;	/* supported pm features */
  	unsigned int        power_notify_type;

@@ -320,6 +322,8 @@ struct mmc_host {
 
  	unsigned int		actual_clock;	/* Actual HC clock rate */
 
+	struct delayed_work	start_bkops;	/* Periodic bkops start */
+
  	unsigned long		private[0] ____cacheline_aligned;
  };
 

include/linux/mmc/mmc.h +20 -1

index d425cab..06afeb4 100644
@@ -139,6 +139,7 @@ static inline bool mmc_op_multi(u32 opcode)
  #define R1_CURRENT_STATE(x)	((x&  0x00001E00)>>  9)	/* sx, b (4 bits) */
  #define R1_READY_FOR_DATA	(1<<  8)	/* sx, a */
  #define R1_SWITCH_ERROR		(1<<  7)	/* sx, c */
+#define R1_EXCEPTION_EVENT	(1<<  6)	/* sx, a */
  #define R1_APP_CMD		(1<<  5)	/* sr, c */
 
  #define R1_STATE_IDLE	0

@@ -274,12 +275,15 @@ struct _mmc_csd {
  #define EXT_CSD_FLUSH_CACHE		32      /* W */
  #define EXT_CSD_CACHE_CTRL		33      /* R/W */
  #define EXT_CSD_POWER_OFF_NOTIFICATION	34	/* R/W */
+#define EXT_CSD_EXCEPTION_STATUS	54	/* RO */
  #define EXT_CSD_DATA_SECTOR_SIZE	61	/* R */
  #define EXT_CSD_GP_SIZE_MULT		143	/* R/W */
  #define EXT_CSD_PARTITION_ATTRIBUTE	156	/* R/W */
  #define EXT_CSD_PARTITION_SUPPORT	160	/* RO */
  #define EXT_CSD_HPI_MGMT		161	/* R/W */
  #define EXT_CSD_RST_N_FUNCTION		162	/* R/W */
+#define EXT_CSD_BKOPS_EN		163	/* R/W */
+#define EXT_CSD_BKOPS_START		164	/* W */
  #define EXT_CSD_SANITIZE_START		165     /* W */
  #define EXT_CSD_WR_REL_PARAM		166	/* RO */
  #define EXT_CSD_BOOT_WP			173	/* R/W */

@@ -313,11 +317,13 @@ struct _mmc_csd {
  #define EXT_CSD_PWR_CL_200_360		237	/* RO */
  #define EXT_CSD_PWR_CL_DDR_52_195	238	/* RO */
  #define EXT_CSD_PWR_CL_DDR_52_360	239	/* RO */
+#define EXT_CSD_BKOPS_STATUS		246	/* RO */
  #define EXT_CSD_POWER_OFF_LONG_TIME	247	/* RO */
  #define EXT_CSD_GENERIC_CMD6_TIME	248	/* RO */
  #define EXT_CSD_CACHE_SIZE		249	/* RO, 4 bytes */
  #define EXT_CSD_TAG_UNIT_SIZE		498	/* RO */
  #define EXT_CSD_DATA_TAG_SUPPORT	499	/* RO */
+#define EXT_CSD_BKOPS_SUPPORT		502	/* RO */
  #define EXT_CSD_HPI_FEATURES		503	/* RO */
 
  /*

@@ -386,4 +392,18 @@ struct _mmc_csd {
  #define MMC_SWITCH_MODE_CLEAR_BITS	0x02	/* Clear bits which are 1 in value */
  #define MMC_SWITCH_MODE_WRITE_BYTE	0x03	/* Set target to value */
 
+/*
+ * BKOPS status level
+ */
+#define EXT_CSD_BKOPS_LEVEL_2		0x2
+#define EXT_CSD_BKOPS_LEVEL_3		0x3
+
+/*
+ * EXCEPTION_EVENT_STATUS field (eMMC4.5)
+ */
+#define EXT_CSD_URGENT_BKOPS		BIT(0)
+#define EXT_CSD_DYNCAP_NEEDED		BIT(1)
+#define EXT_CSD_SYSPOOL_EXHAUSTED	BIT(2)
+#define EXT_CSD_PACKED_FAILURE		BIT(3)
+
  #endif /* LINUX_MMC_MMC_H */
--

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Hi Jaehoon,

Please find comments inline below.

Quoted 70 lines · Jaehoon Chung

Enable eMMC background operations (BKOPS) feature.

If URGENT_BKOPS is set after a response, note that BKOPS are required. After all I/O requests are finished, run BKOPS if required. Should read/write operations be requested during BKOPS, first issue HPI to interrupt the ongoing BKOPS and then service the request.
If BKOPS-STATUS is upper than LEVEL2, need to check until clear the BKOPS-STATUS vaule.

If you want to enable this feature, set MMC_CAP2_BKOPS. And if you want to set the BKOPS_EN bit in ext_csd register, use the MMC_CAP2_INIT_BKOPS.

When BKOPS_STATUS is Level-3, if we're waiting for done, it spent 60~80sec. So Added timeout value. if timeout value is set to 0, send hpi command.

Signed-off-by Jaehoon Chung<[email protected]>

Signed-off-by Kyungmin Park<[email protected]>

---
Changelog V8:
- Remove host->lock spin lock reviewed by Adrian
- Support periodic start bkops
- when bkops_status is level-3, if timeout is set to 0, send hpi.
- Move the start-bkops point
Changelog V7:
- Use HPI command when issued URGENT_BKOPS
- Recheck until clearing the bkops-status bit.
Changelog V6:
- Add the flag of check-bkops-status.
(For fixing async_req problem)
- Add the capability for MMC_CAP2_INIT_BKOPS.
(When unset the bkops_en bit in ext_csd register)
- modify the wrong condition.
Changelog V5:
- Rebase based on the latest mmc-next.
- modify codes based-on Chris's comment
Changelog V4:
- Add mmc_read_bkops_status
- When URGENT_BKOPS(level2-3), didn't use HPI command.
- In mmc_switch(), use R1B/R1 according to level.
Changelog V3:
- move the bkops setting's location in mmc_blk_issue_rw_rq
- modify condition checking
- bkops_en is assigned ext_csd[EXT_CSD_BKOPS_EN] instead of "1"
- remove the unused code
- change pr_debug instead of pr_warn in mmc_send_hpi_cmd
- Add the Future consideration suggested by Per
Changelog V2:
- Use EXCEPTION_STATUS instead of URGENT_BKOPS
- Add function to check Exception_status(for eMMC4.5)

---
  drivers/mmc/card/queue.c   |    2 +
  drivers/mmc/core/core.c    |  170 +++++++++++++++++++++++++++++++++++++++++++-
  drivers/mmc/core/host.c    |    1 +
  drivers/mmc/core/mmc.c     |   18 +++++
  drivers/mmc/core/mmc_ops.c |    4 +
  include/linux/mmc/card.h   |   16 ++++
  include/linux/mmc/core.h   |    5 ++
  include/linux/mmc/host.h   |    4 +
  include/linux/mmc/mmc.h    |   20 +++++
  9 files changed, 238 insertions(+), 2 deletions(-)

drivers/mmc/card/queue.c +0 -0

index e360a97..e4a2cde 100644
@@ -66,6 +66,8 @@ static int mmc_queue_thread(void *d)
          spin_unlock_irq(q->queue_lock);
 

drivers/mmc/card/queue.c static int mmc_queue_thread(void *d) · line 70

Quoted 3 lines

drivers/mmc/card/queue.c +2 -0

          if (req || mq->mqrq_prev->req) {
+            if (mmc_card_doing_bkops(mq->card))
+                mmc_stop_bkops(mq->card);

mmc_stop_bkops() may fail and can return an error but we are ignoring it here. What if this function has returned error which means BKOPS may still be running in card and if you go ahead and issue another read/write request?

Quoted 11 lines

drivers/mmc/card/queue.c +0 -0

              set_current_state(TASK_RUNNING);
              mq->issue_fn(mq, req);
          } else {

drivers/mmc/core/core.c +0 -0

index 0b6141d..91a03d5 100644
@@ -175,6 +175,13 @@ void mmc_request_done(struct mmc_host *host, struct mmc_request *mrq)
          if (mrq->done)
              mrq->done(mrq);
 

drivers/mmc/core/core.c void mmc_request_done(struct mmc_host *host, struct mmc_request *mrq)

Quoted 5 lines

drivers/mmc/core/core.c +5 -0

+        /*
+         * Check BKOPS urgency from each R1 response
+         */
+        if (host->card&&  mmc_card_mmc(host->card)&&
+            (cmd->resp[0]&  R1_EXCEPTION_EVENT))

Shouldn't you make sure that response expected for this commands is R1/R1b? Only in that case cmd->resp[0] will have the device status.

drivers/mmc/core/core.c mmc_start_request(struct mmc_host *host, struct mmc_request *mrq) · line 255

Quoted 10 lines

drivers/mmc/core/core.c +3 -0

+            mmc_card_set_check_bkops(host->card);
+
          mmc_host_clk_release(host);
      }
  }

@@ -245,6 +252,76 @@ mmc_start_request(struct mmc_host *host, struct mmc_request *mrq)
      host->ops->request(host, mrq);
  }
 
+static void mmc_send_bkops_cmd(struct mmc_card *card)

I guess name should be mmc_send_bkops_start_cmd().

drivers/mmc/core/core.c mmc_start_request(struct mmc_host *host, struct mmc_request *mrq) · line 266

Quoted 11 lines

drivers/mmc/core/core.c +11 -0

+{
+    int err;
+
+    BUG_ON(!card);
+
+    err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
+            EXT_CSD_BKOPS_START, 1, 0);
+    if (err) {
+        pr_warning("%s: error %d starting bkops\n",
+               mmc_hostname(card->host), err);
+        mmc_card_clr_need_bkops(card);

In case of failure, why are we clearing the NEED_BKOPS flag? You still need the BKOPS, correct?

drivers/mmc/core/core.c mmc_start_request(struct mmc_host *host, struct mmc_request *mrq) · line 272

Quoted 6 lines

drivers/mmc/core/core.c +6 -0

+        return;
+    }
+
+    mmc_card_clr_need_bkops(card);
+    mmc_card_set_doing_bkops(card);
+

You can remove this extra line here.

Quoted 42 lines

drivers/mmc/core/core.c +42 -0

+}
+
+void mmc_start_periodic_bkops(struct work_struct *work)
+{
+    struct mmc_host *host = container_of(work, struct mmc_host,
+            start_bkops.work);
+
+    mmc_card_set_check_bkops(host->card);
+
+    mmc_claim_host(host);
+    mmc_start_bkops(host->card);
+    mmc_release_host(host);
+}
+EXPORT_SYMBOL(mmc_start_periodic_bkops);
+
+/**
+ *    mmc_start_bkops - start BKOPS for supported cards
+ *    @card: MMC card to start BKOPS
+ *
+ *    Start background operations whenever requested.
+ *    when the urgent BKOPS bit is set in a R1 command response
+ *    then background operations should be started immediately.
+*/
+void mmc_start_bkops(struct mmc_card *card)
+{
+    BUG_ON(!card);
+    if (!card->ext_csd.bkops_en || !(card->host->caps2&  MMC_CAP2_BKOPS))
+        return;
+
+    if (mmc_card_check_bkops(card)) {
+        mmc_card_clr_check_bkops(card);
+        if (mmc_is_exception_event(card, EXT_CSD_URGENT_BKOPS)) {
+            if (card->ext_csd.raw_bkops_status)
+                mmc_card_set_need_bkops(card);
+        } else
+            mmc_card_clr_need_bkops(card);
+    }
+
+    /*
+     * If card_need_bkops_flag didn't set, then do nothing just
+     * return
+     */

drivers/mmc/core/core.c mmc_start_request(struct mmc_host *host, struct mmc_request *mrq)

Quoted 7 lines

drivers/mmc/core/core.c +7 -0

+    if (mmc_card_doing_bkops(card) || !mmc_card_need_bkops(card))
+        goto check_bkops;
+
+    mmc_send_bkops_cmd(card);
+
+check_bkops:
+    queue_delayed_work(system_nrt_wq,&card->host->start_bkops, 5 * HZ);

Can we use the deferrable timer for this delayed work? If it's not deferrable and if CPU is some low power state, it has to wakeup and serve this timer on it's expiration. Better make it deferrable so it won't wakeup the system when timer expires.

Also, just wondering, how came to this 5 sec timeout?

Quoted 34 lines

drivers/mmc/core/core.c +10 -2

+}
+EXPORT_SYMBOL(mmc_start_bkops);
+
  static void mmc_wait_done(struct mmc_request *mrq)
  {
      complete(&mrq->completion);

@@ -348,8 +425,10 @@ struct mmc_async_req *mmc_start_req(struct mmc_host *host,
      struct mmc_async_req *data = host->areq;
 
      /* Prepare a new request */
-    if (areq)
+    if (areq) {
+        cancel_delayed_work_sync(&host->start_bkops);
          mmc_pre_req(host, areq->mrq, !host->areq);
+    }
 
      if (host->areq) {
          mmc_wait_for_req_done(host, host->areq->mrq);

@@ -359,8 +438,11 @@ struct mmc_async_req *mmc_start_req(struct mmc_host *host,
      if (!err&&  areq)
          start_err = __mmc_start_req(host, areq->mrq);
 
-    if (host->areq)
+    if (host->areq) {
          mmc_post_req(host, host->areq->mrq, 0);
+        if (!areq&&  host->areq&&  mmc_card_mmc(host->card))
+            mmc_start_bkops(host->card);
+    }
 
       /* Cancel a prepared request if it was not started. */
      if ((err || start_err)&&  areq)

@@ -480,6 +562,84 @@ int mmc_wait_for_cmd(struct mmc_host *host, struct mmc_command *cmd, int retries
  EXPORT_SYMBOL(mmc_wait_for_cmd);
 

drivers/mmc/core/core.c int mmc_wait_for_cmd(struct mmc_host *host, struct mmc_command *cmd, int retries · line 576

Quoted 13 lines

drivers/mmc/core/core.c +12 -0

  /**
+ *    mmc_stop_bkops - stop ongoing BKOPS
+ *    @card: MMC card to check BKOPS
+ *
+ *    Send HPI command to interrupt ongoing background operations,
+ *    to allow rapid servicing of foreground operations,e.g. read/
+ *    writes. Wait until the card comes out of the programming state
+ *    to avoid errors in servicing read/write requests.
+ */
+int mmc_stop_bkops(struct mmc_card *card)
+{
+    int err = 0;
+    unsigned int timeout = 0x10000;

How this 0x10000 value is calculated? Is there any defined timeout value for card to come out of programming after starting the BKOPS? if not, then let's wait indefinitely for it to come out of the programming state? Don't we wait indefinitely for write request?

Quoted 16 lines

drivers/mmc/core/core.c +16 -0

+    u32 status;
+
+    BUG_ON(!card);
+    cancel_delayed_work_sync(&card->host->start_bkops);
+
+    if (card->ext_csd.raw_bkops_status == EXT_CSD_BKOPS_LEVEL_3) {
+        do {
+            if (timeout == 0)
+                break;
+            mmc_claim_host(card->host);
+            mmc_send_status(card,&status);
+            mmc_release_host(card->host);
+
+            timeout--;
+        } while (R1_CURRENT_STATE(status) == R1_STATE_PRG);
+        if (timeout != 0)

drivers/mmc/core/core.c int mmc_wait_for_cmd(struct mmc_host *host, struct mmc_command *cmd, int retries · line 599

Quoted 7 lines

drivers/mmc/core/core.c +7 -0

+            goto done;
+    }
+
+    err = mmc_interrupt_hpi(card);
+
+done:
+    mmc_card_clr_doing_bkops(card);

Here even if mmc_interrupt_hpi() fails, you are clearing the DOING_BKOPS flag which is not correct. Which should clear this flag if HPI issued successfully.

Quoted 281 lines

drivers/mmc/core/core.c +49 -0

+
+    return err;
+}
+EXPORT_SYMBOL(mmc_stop_bkops);
+
+int mmc_read_bkops_status(struct mmc_card *card)
+{
+    int err;
+    u8 ext_csd[512];
+
+    mmc_claim_host(card->host);
+    err = mmc_send_ext_csd(card, ext_csd);
+    mmc_release_host(card->host);
+    if (err)
+        return err;
+
+    card->ext_csd.raw_bkops_status = ext_csd[EXT_CSD_BKOPS_STATUS];
+    card->ext_csd.raw_exception_status = ext_csd[EXT_CSD_EXCEPTION_STATUS];
+
+    return 0;
+}
+EXPORT_SYMBOL(mmc_read_bkops_status);
+
+int mmc_is_exception_event(struct mmc_card *card, unsigned int value)
+{
+    int err;
+
+    err = mmc_read_bkops_status(card);
+    if (err) {
+        pr_err("%s: Didn't read bkops status : %d\n",
+               mmc_hostname(card->host), err);
+        return 0;
+    }
+
+    /* In eMMC 4.41, R1_EXCEPTION_EVENT is URGENT_BKOPS */
+    if (card->ext_csd.rev == 5)
+        return 1;
+
+    return (card->ext_csd.raw_exception_status&  value) ? 1 : 0;
+}
+EXPORT_SYMBOL(mmc_is_exception_event);
+
+/**
   *    mmc_set_data_timeout - set the timeout for a data command
   *    @data: data phase for command
   *    @card: the MMC card associated with the data transfer

@@ -2382,6 +2542,12 @@ int mmc_pm_notify(struct notifier_block *notify_block,
      switch (mode) {
      case PM_HIBERNATION_PREPARE:
      case PM_SUSPEND_PREPARE:
+        if (host->card&&  mmc_card_mmc(host->card)&&
+                mmc_card_doing_bkops(host->card)) {
+            mmc_interrupt_hpi(host->card);
+            mmc_card_clr_doing_bkops(host->card);
+        }
+        cancel_delayed_work_sync(&host->start_bkops);
 
          spin_lock_irqsave(&host->lock, flags);
          host->rescan_disable = 1;

drivers/mmc/core/host.c +1 -0

index 91c84c7..3b6a8e4 100644
@@ -330,6 +330,7 @@ struct mmc_host *mmc_alloc_host(int extra, struct device *dev)
      spin_lock_init(&host->lock);
      init_waitqueue_head(&host->wq);
      INIT_DELAYED_WORK(&host->detect, mmc_rescan);
+    INIT_DELAYED_WORK(&host->start_bkops, mmc_start_periodic_bkops);
  #ifdef CONFIG_PM
      host->pm_notify.notifier_call = mmc_pm_notify;
  #endif

drivers/mmc/core/mmc.c +18 -0

index 2f0e11c..275555a 100644
@@ -463,6 +463,24 @@ static int mmc_read_ext_csd(struct mmc_card *card, u8 *ext_csd)
      }
 
      if (card->ext_csd.rev>= 5) {
+        /* check whether the eMMC card support BKOPS */
+        if (ext_csd[EXT_CSD_BKOPS_SUPPORT]&  0x1) {
+            card->ext_csd.bkops = 1;
+            card->ext_csd.bkops_en = ext_csd[EXT_CSD_BKOPS_EN];
+            card->ext_csd.raw_bkops_status =
+                ext_csd[EXT_CSD_BKOPS_STATUS];
+            if (!card->ext_csd.bkops_en&&
+                card->host->caps2&  MMC_CAP2_INIT_BKOPS) {
+                err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
+                    EXT_CSD_BKOPS_EN, 1, 0);
+                if (err)
+                    pr_warning("%s: Enabling BKOPS failed\n",
+                        mmc_hostname(card->host));
+                else
+                    card->ext_csd.bkops_en = 1;
+            }
+        }
+
          /* check whether the eMMC card supports HPI */
          if (ext_csd[EXT_CSD_HPI_FEATURES]&  0x1) {
              card->ext_csd.hpi = 1;

drivers/mmc/core/mmc_ops.c +4 -0

index 69370f4..bc8da17 100644
@@ -399,6 +399,10 @@ int mmc_switch(struct mmc_card *card, u8 set, u8 index, u8 value,
      if (err)
          return err;
 
+    /* No need to check card status in case of BKOPS switch*/
+    if (index == EXT_CSD_BKOPS_START)
+        return 0;
+
      /* Must check status to be sure of no errors */
      do {
          err = mmc_send_status(card,&status);

include/linux/mmc/card.h +16 -0

index d76513b..52b507d 100644
@@ -76,6 +76,9 @@ struct mmc_ext_csd {
      bool            hpi_en;            /* HPI enablebit */
      bool            hpi;            /* HPI support bit */
      unsigned int        hpi_cmd;        /* cmd used as HPI */
+    bool            bkops;        /* background support bit */
+    bool            bkops_en;    /* background enable bit */
+    u8            raw_exception_status;    /* 53 */
      unsigned int            data_sector_size;       /* 512 bytes or 4KB */
      unsigned int            data_tag_unit_size;     /* DATA TAG UNIT size */
      unsigned int        boot_ro_lock;        /* ro lock support */

@@ -93,6 +96,7 @@ struct mmc_ext_csd {
      u8            raw_sec_erase_mult;    /* 230 */
      u8            raw_sec_feature_support;/* 231 */
      u8            raw_trim_mult;        /* 232 */
+    u8            raw_bkops_status;    /* 246 */
      u8            raw_sectors[4];        /* 212 - 4 bytes */
 
      unsigned int            feature_support;

@@ -225,6 +229,9 @@ struct mmc_card {
  #define MMC_CARD_REMOVED    (1<<7)        /* card has been removed */
  #define MMC_STATE_HIGHSPEED_200    (1<<8)        /* card is in HS200 mode */
  #define MMC_STATE_SLEEP        (1<<9)        /* card is in sleep state */
+#define MMC_STATE_NEED_BKOPS    (1<<10)        /* card need to do BKOPS */
+#define MMC_STATE_DOING_BKOPS    (1<<11)        /* card is doing BKOPS */
+#define MMC_STATE_CHECK_BKOPS    (1<<12)        /* card need to check BKOPS */
      unsigned int        quirks;     /* card quirks */
  #define MMC_QUIRK_LENIENT_FN0    (1<<0)        /* allow SDIO FN0 writes outside of the VS CCCR range */
  #define MMC_QUIRK_BLKSZ_FOR_BYTE_MODE (1<<1)    /* use func->cur_blksize */

@@ -391,6 +398,9 @@ static inline void __maybe_unused remove_quirk(struct mmc_card *card, int data)
  #define mmc_card_ext_capacity(c) ((c)->state&  MMC_CARD_SDXC)
  #define mmc_card_removed(c)    ((c)&&  ((c)->state&  MMC_CARD_REMOVED))
  #define mmc_card_is_sleep(c)    ((c)->state&  MMC_STATE_SLEEP)
+#define mmc_card_need_bkops(c)    ((c)->state&  MMC_STATE_NEED_BKOPS)
+#define mmc_card_doing_bkops(c)    ((c)->state&  MMC_STATE_DOING_BKOPS)
+#define mmc_card_check_bkops(c) ((c)->state&  MMC_STATE_CHECK_BKOPS)
 
  #define mmc_card_set_present(c)    ((c)->state |= MMC_STATE_PRESENT)
  #define mmc_card_set_readonly(c) ((c)->state |= MMC_STATE_READONLY)

@@ -403,7 +413,13 @@ static inline void __maybe_unused remove_quirk(struct mmc_card *card, int data)
  #define mmc_card_set_ext_capacity(c) ((c)->state |= MMC_CARD_SDXC)
  #define mmc_card_set_removed(c) ((c)->state |= MMC_CARD_REMOVED)
  #define mmc_card_set_sleep(c)    ((c)->state |= MMC_STATE_SLEEP)
+#define mmc_card_set_need_bkops(c)    ((c)->state |= MMC_STATE_NEED_BKOPS)
+#define mmc_card_set_doing_bkops(c)    ((c)->state |= MMC_STATE_DOING_BKOPS)
+#define mmc_card_set_check_bkops(c) ((c)->state |= MMC_STATE_CHECK_BKOPS)
 
+#define mmc_card_clr_need_bkops(c)    ((c)->state&= ~MMC_STATE_NEED_BKOPS)
+#define mmc_card_clr_doing_bkops(c)    ((c)->state&= ~MMC_STATE_DOING_BKOPS)
+#define mmc_card_clr_check_bkops(c) ((c)->state&= ~MMC_STATE_CHECK_BKOPS)
  #define mmc_card_clr_sleep(c)    ((c)->state&= ~MMC_STATE_SLEEP)
  /*
   * Quirk add/remove for MMC products.

include/linux/mmc/core.h +5 -0

index 1b431c7..c920250 100644
@@ -134,6 +134,9 @@ struct mmc_host;
  struct mmc_card;
  struct mmc_async_req;
 
+extern int mmc_stop_bkops(struct mmc_card *);
+extern int mmc_read_bkops_status(struct mmc_card *);
+extern int mmc_is_exception_event(struct mmc_card *, unsigned int);
  extern struct mmc_async_req *mmc_start_req(struct mmc_host *,
                         struct mmc_async_req *, int *);
  extern int mmc_interrupt_hpi(struct mmc_card *);

@@ -163,6 +166,8 @@ extern int mmc_can_sanitize(struct mmc_card *card);
  extern int mmc_can_secure_erase_trim(struct mmc_card *card);
  extern int mmc_erase_group_aligned(struct mmc_card *card, unsigned int from,
                     unsigned int nr);
+extern void mmc_start_periodic_bkops(struct work_struct *work);
+extern void mmc_start_bkops(struct mmc_card *card);
  extern unsigned int mmc_calc_max_discard(struct mmc_card *card);
 
  extern int mmc_set_blocklen(struct mmc_card *card, unsigned int blocklen);

include/linux/mmc/host.h +4 -0

index 0707d22..186d146 100644
@@ -238,6 +238,8 @@ struct mmc_host {
  #define MMC_CAP2_BROKEN_VOLTAGE    (1<<  7)    /* Use the broken voltage */
  #define MMC_CAP2_DETECT_ON_ERR    (1<<  8)    /* On I/O err check card removal */
  #define MMC_CAP2_HC_ERASE_SZ    (1<<  9)    /* High-capacity erase size */
+#define MMC_CAP2_INIT_BKOPS    (1<<  10)    /* To enable BKOPS */
+#define MMC_CAP2_BKOPS        (1<<  11)    /* BKOPS supported */
 
      mmc_pm_flag_t        pm_caps;    /* supported pm features */
      unsigned int        power_notify_type;

@@ -320,6 +322,8 @@ struct mmc_host {
 
      unsigned int        actual_clock;    /* Actual HC clock rate */
 
+    struct delayed_work    start_bkops;    /* Periodic bkops start */
+
      unsigned long        private[0] ____cacheline_aligned;
  };
 

include/linux/mmc/mmc.h +20 -0

index d425cab..06afeb4 100644
@@ -139,6 +139,7 @@ static inline bool mmc_op_multi(u32 opcode)
  #define R1_CURRENT_STATE(x)    ((x&  0x00001E00)>>  9)    /* sx, b (4 bits) */
  #define R1_READY_FOR_DATA    (1<<  8)    /* sx, a */
  #define R1_SWITCH_ERROR        (1<<  7)    /* sx, c */
+#define R1_EXCEPTION_EVENT    (1<<  6)    /* sx, a */
  #define R1_APP_CMD        (1<<  5)    /* sr, c */
 
  #define R1_STATE_IDLE    0

@@ -274,12 +275,15 @@ struct _mmc_csd {
  #define EXT_CSD_FLUSH_CACHE        32      /* W */
  #define EXT_CSD_CACHE_CTRL        33      /* R/W */
  #define EXT_CSD_POWER_OFF_NOTIFICATION    34    /* R/W */
+#define EXT_CSD_EXCEPTION_STATUS    54    /* RO */
  #define EXT_CSD_DATA_SECTOR_SIZE    61    /* R */
  #define EXT_CSD_GP_SIZE_MULT        143    /* R/W */
  #define EXT_CSD_PARTITION_ATTRIBUTE    156    /* R/W */
  #define EXT_CSD_PARTITION_SUPPORT    160    /* RO */
  #define EXT_CSD_HPI_MGMT        161    /* R/W */
  #define EXT_CSD_RST_N_FUNCTION        162    /* R/W */
+#define EXT_CSD_BKOPS_EN        163    /* R/W */
+#define EXT_CSD_BKOPS_START        164    /* W */
  #define EXT_CSD_SANITIZE_START        165     /* W */
  #define EXT_CSD_WR_REL_PARAM        166    /* RO */
  #define EXT_CSD_BOOT_WP            173    /* R/W */

@@ -313,11 +317,13 @@ struct _mmc_csd {
  #define EXT_CSD_PWR_CL_200_360        237    /* RO */
  #define EXT_CSD_PWR_CL_DDR_52_195    238    /* RO */
  #define EXT_CSD_PWR_CL_DDR_52_360    239    /* RO */
+#define EXT_CSD_BKOPS_STATUS        246    /* RO */
  #define EXT_CSD_POWER_OFF_LONG_TIME    247    /* RO */
  #define EXT_CSD_GENERIC_CMD6_TIME    248    /* RO */
  #define EXT_CSD_CACHE_SIZE        249    /* RO, 4 bytes */
  #define EXT_CSD_TAG_UNIT_SIZE        498    /* RO */
  #define EXT_CSD_DATA_TAG_SUPPORT    499    /* RO */
+#define EXT_CSD_BKOPS_SUPPORT        502    /* RO */
  #define EXT_CSD_HPI_FEATURES        503    /* RO */
 
  /*

@@ -386,4 +392,18 @@ struct _mmc_csd {
  #define MMC_SWITCH_MODE_CLEAR_BITS    0x02    /* Clear bits which are 1 in value */
  #define MMC_SWITCH_MODE_WRITE_BYTE    0x03    /* Set target to value */
 
+/*
+ * BKOPS status level
+ */
+#define EXT_CSD_BKOPS_LEVEL_2        0x2
+#define EXT_CSD_BKOPS_LEVEL_3        0x3
+
+/*
+ * EXCEPTION_EVENT_STATUS field (eMMC4.5)
+ */
+#define EXT_CSD_URGENT_BKOPS        BIT(0)
+#define EXT_CSD_DYNCAP_NEEDED        BIT(1)
+#define EXT_CSD_SYSPOOL_EXHAUSTED    BIT(2)
+#define EXT_CSD_PACKED_FAILURE        BIT(3)
+
  #endif /* LINUX_MMC_MMC_H */

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