mmc: core: hw_reset changes

The steps performed in mmc_do_hw_reset for eMMC:s after the hardware reset are very similar to those performed by mmc_power_up, so do a call

to this function instead.

Signed-off-by Johan Rudholm <[email protected]>

---
 drivers/mmc/core/core.c |   11 +----------
 1 files changed, 1 insertions(+), 10 deletions(-)

drivers/mmc/core/core.c +1 -10

index 5d215ee..d56e222 100644
@@ -2273,16 +2273,7 @@ static int mmc_do_hw_reset(struct mmc_host *host, int check)
 		}
 	}
 
-	if (mmc_host_is_spi(host)) {
-		host->ios.chip_select = MMC_CS_HIGH;
-		host->ios.bus_mode = MMC_BUSMODE_PUSHPULL;
-	} else {
-		host->ios.chip_select = MMC_CS_DONTCARE;
-		host->ios.bus_mode = MMC_BUSMODE_OPENDRAIN;
-	}
-	host->ios.bus_width = MMC_BUS_WIDTH_1;
-	host->ios.timing = MMC_TIMING_LEGACY;
-	mmc_set_ios(host);
+	mmc_power_up(host, card->ocr);
 
 	mmc_host_clk_release(host);
 

Quoted 2 lines

The steps performed in mmc_do_hw_reset for eMMC:s after the hardware reset are very similar to those performed by mmc_power_up, so do a call

They perform different functions. mmc_power_up() does nothing if the card is powered up. To share the common code you need to create a function for the common functionality which is setting the initial state e.g.

int mmc_set_initial_state(struct mmc_host *host)

{
        ...
}

And call that from mmc_do_hw_reset and mmc_power_up.

2014-11-03 10:21 GMT+01:00 Adrian Hunter <[email protected]>:

Quoted 13 lines · Johan Rudholm

Quoted 2 lines

The steps performed in mmc_do_hw_reset for eMMC:s after the hardware reset are very similar to those performed by mmc_power_up, so do a call

They perform different functions. mmc_power_up() does nothing if the card is powered up. To share the common code you need to create a function for the common functionality which is setting the initial state e.g.

int mmc_set_initial_state(struct mmc_host *host)

{
        ...
}

Quoted 1 line

And call that from mmc_do_hw_reset and mmc_power_up.

Thank you for the comment. What do you think of doing a complete mmc_power_cycle after having performed a (successful) reset? In this way we can simplify the SD card reset and we don't have to break out the common code from mmc_power_up. Naming discussion apart, something like this:

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

index 486cda8..941f631 100644
@@ -2236,12 +2236,15 @@ static void mmc_hw_reset_for_init(struct mmc_host *host)
 static int mmc_do_reset(struct mmc_host *host, int check)
 {
        int ret;
+       struct mmc_card *card = host->card;
 
        if (!host->bus_ops || !host->bus_ops->power_reset ||
                        host->bus_ops->power_reset(host, MMC_POWER_RESET_TEST))
                return -EOPNOTSUPP;
 
        ret = host->bus_ops->power_reset(host, check);
+       if (!ret && card)
+               mmc_power_cycle(host, card->ocr);
 
        pr_warning("%s: tried to reset card (%d)\n", mmc_hostname(host), ret);
 

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

index ac5192c..900133a 100644
@@ -1794,8 +1794,6 @@ static int mmc_power_reset(struct mmc_host
 *host, int test)
                }
        }
 
-       mmc_power_up(host, card->ocr);
-
        mmc_host_clk_release(host);
 

        return 0;

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

index 9ad46b2..d5b8ee7 100644
@@ -1187,8 +1187,6 @@ static int mmc_sd_power_reset(struct mmc_host
 *host, int test)
        if (test == MMC_POWER_RESET_TEST)
                return 0;
 
-       mmc_power_cycle(host, card->ocr);
-
        return 0;
 }

//Johan

Move the (e)MMC specific hw_reset code from core.c into mmc.c and call it from the new bus_ops member power_reset. This also lets us add code

for reseting SD cards as well.

Rename the mmc_hw_reset* functions into mmc_reset*, since what they now actually do depends on the device type (and it may be something else than doing a hw_reset).

Signed-off-by Johan Rudholm <[email protected]>

---
 drivers/mmc/card/block.c    |    2 +-
 drivers/mmc/card/mmc_test.c |    5 +---
 drivers/mmc/core/core.c     |   58 +++++++++---------------------------------
 drivers/mmc/core/core.h     |    4 +++
 drivers/mmc/core/mmc.c      |   40 +++++++++++++++++++++++++++++
 include/linux/mmc/core.h    |    5 +--
 6 files changed, 61 insertions(+), 53 deletions(-)

drivers/mmc/card/block.c +1 -1

index 452782b..8c4fa46 100644
@@ -1001,7 +1001,7 @@ static int mmc_blk_reset(struct mmc_blk_data *md, struct mmc_host *host,
 		return -EEXIST;
 
 	md->reset_done |= type;
-	err = mmc_hw_reset(host);
+	err = mmc_reset(host);
 	/* Ensure we switch back to the correct partition */
 	if (err != -EOPNOTSUPP) {
 		struct mmc_blk_data *main_md = mmc_get_drvdata(host->card);

drivers/mmc/card/mmc_test.c +1 -4

index 0c0fc52..599c683 100644
@@ -2339,7 +2339,7 @@ static int mmc_test_hw_reset(struct mmc_test_card *test)
 	struct mmc_host *host = card->host;
 	int err;
 
-	err = mmc_hw_reset_check(host);
+	err = mmc_reset_check(host);
 	if (!err)
 		return RESULT_OK;
 

@@ -2349,9 +2349,6 @@ static int mmc_test_hw_reset(struct mmc_test_card *test)
 	if (err != -EOPNOTSUPP)
 		return err;
 
-	if (!mmc_can_reset(card))
-		return RESULT_UNSUP_CARD;
-
 	return RESULT_UNSUP_HOST;
 }
 

drivers/mmc/core/core.c +13 -45

index d56e222..486cda8 100644
@@ -2232,65 +2232,33 @@ static void mmc_hw_reset_for_init(struct mmc_host *host)
 	mmc_host_clk_release(host);
 }
 
-int mmc_can_reset(struct mmc_card *card)
+/* Reset card in a bus-specific way */
+static int mmc_do_reset(struct mmc_host *host, int check)
 {
-	u8 rst_n_function;
-
-	if (!mmc_card_mmc(card))
-		return 0;
-	rst_n_function = card->ext_csd.rst_n_function;
-	if ((rst_n_function & EXT_CSD_RST_N_EN_MASK) != EXT_CSD_RST_N_ENABLED)
-		return 0;
-	return 1;
-}
-EXPORT_SYMBOL(mmc_can_reset);
-
-static int mmc_do_hw_reset(struct mmc_host *host, int check)
-{
-	struct mmc_card *card = host->card;
-
-	if (!(host->caps & MMC_CAP_HW_RESET) || !host->ops->hw_reset)
-		return -EOPNOTSUPP;
-
-	if (!card)
-		return -EINVAL;
+	int ret;
 
-	if (!mmc_can_reset(card))
+	if (!host->bus_ops || !host->bus_ops->power_reset ||
+			host->bus_ops->power_reset(host, MMC_POWER_RESET_TEST))
 		return -EOPNOTSUPP;
 
-	mmc_host_clk_hold(host);
-	mmc_set_clock(host, host->f_init);
-
-	host->ops->hw_reset(host);
-
-	/* If the reset has happened, then a status command will fail */
-	if (check) {
-		u32 status;
-
-		if (!mmc_send_status(card, &status)) {
-			mmc_host_clk_release(host);
-			return -ENOSYS;
-		}
-	}
-
-	mmc_power_up(host, card->ocr);
+	ret = host->bus_ops->power_reset(host, check);
 
-	mmc_host_clk_release(host);
+	pr_warning("%s: tried to reset card (%d)\n", mmc_hostname(host), ret);
 
 	return host->bus_ops->power_restore(host);
 }
 
-int mmc_hw_reset(struct mmc_host *host)
+int mmc_reset(struct mmc_host *host)
 {
-	return mmc_do_hw_reset(host, 0);
+	return mmc_do_reset(host, MMC_POWER_RESET_RESET);
 }
-EXPORT_SYMBOL(mmc_hw_reset);
+EXPORT_SYMBOL(mmc_reset);
 
-int mmc_hw_reset_check(struct mmc_host *host)
+int mmc_reset_check(struct mmc_host *host)
 {
-	return mmc_do_hw_reset(host, 1);
+	return mmc_do_reset(host, MMC_POWER_RESET_CHECK);
 }
-EXPORT_SYMBOL(mmc_hw_reset_check);
+EXPORT_SYMBOL(mmc_reset_check);
 
 static int mmc_rescan_try_freq(struct mmc_host *host, unsigned freq)
 {

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

index 443a584..6a0420b 100644
@@ -25,6 +25,10 @@ struct mmc_bus_ops {
 	int (*runtime_resume)(struct mmc_host *);
 	int (*power_save)(struct mmc_host *);
 	int (*power_restore)(struct mmc_host *);
+	int (*power_reset)(struct mmc_host *, int);
+#define MMC_POWER_RESET_RESET	0
+#define MMC_POWER_RESET_TEST	1
+#define MMC_POWER_RESET_CHECK	2
 	int (*alive)(struct mmc_host *);
 	int (*shutdown)(struct mmc_host *);
 };

drivers/mmc/core/mmc.c +40 -0

index 793c6f7..ac5192c 100644
@@ -1762,6 +1762,45 @@ static int mmc_runtime_resume(struct mmc_host *host)
 	return 0;
 }
 
+static int mmc_power_reset(struct mmc_host *host, int test)
+{
+	struct mmc_card *card = host->card;
+	u8 rst_n_function;
+
+	if (!card)
+		return -EINVAL;
+
+	if (!(host->caps & MMC_CAP_HW_RESET) || !host->ops->hw_reset)
+		return -EOPNOTSUPP;
+
+	rst_n_function = card->ext_csd.rst_n_function;
+	if ((rst_n_function & EXT_CSD_RST_N_EN_MASK) != EXT_CSD_RST_N_ENABLED)
+		return -EOPNOTSUPP;
+
+	if (test == MMC_POWER_RESET_TEST)
+		return 0;
+
+	mmc_host_clk_hold(host);
+	mmc_set_clock(host, host->f_init);
+
+	host->ops->hw_reset(host);
+
+	if (test == MMC_POWER_RESET_CHECK) {
+		u32 status;
+
+		if (!mmc_send_status(card, &status)) {
+			mmc_host_clk_release(host);
+			return -ENOSYS;
+		}
+	}
+
+	mmc_power_up(host, card->ocr);
+
+	mmc_host_clk_release(host);
+
+	return 0;
+}
+
 static int mmc_power_restore(struct mmc_host *host)
 {
 	int ret;

@@ -1781,6 +1820,7 @@ static const struct mmc_bus_ops mmc_ops = {
 	.runtime_suspend = mmc_runtime_suspend,
 	.runtime_resume = mmc_runtime_resume,
 	.power_restore = mmc_power_restore,
+	.power_reset = mmc_power_reset,
 	.alive = mmc_alive,
 	.shutdown = mmc_shutdown,
 };

include/linux/mmc/core.h +2 -3

index f206e29..4f7a76e 100644
@@ -180,9 +180,8 @@ extern unsigned int mmc_calc_max_discard(struct mmc_card *card);
 extern int mmc_set_blocklen(struct mmc_card *card, unsigned int blocklen);
 extern int mmc_set_blockcount(struct mmc_card *card, unsigned int blockcount,
 			      bool is_rel_write);
-extern int mmc_hw_reset(struct mmc_host *host);
-extern int mmc_hw_reset_check(struct mmc_host *host);
-extern int mmc_can_reset(struct mmc_card *card);
+extern int mmc_reset(struct mmc_host *host);
+extern int mmc_reset_check(struct mmc_host *host);
 
 extern void mmc_set_data_timeout(struct mmc_data *, const struct mmc_card *);
 extern unsigned int mmc_align_data_size(struct mmc_card *, unsigned int);

Quoted 2 lines

Move the (e)MMC specific hw_reset code from core.c into mmc.c and call it from the new bus_ops member power_reset. This also lets us add code

power_reset is not a good name because it does not necessarily have anything to do with power. I am not sure why you don't stick with hw_reset.

Quoted 5 lines

for reseting SD cards as well.

Rename the mmc_hw_reset* functions into mmc_reset*, since what they now actually do depends on the device type (and it may be something else than doing a hw_reset).

I don't follow your reasoning about the rename. Cycling the power is a kind of hardware reset isn't it.

2014-11-03 10:20 GMT+01:00 Adrian Hunter <[email protected]>:

Quoted 14 lines · Johan Rudholm

Quoted 2 lines

Move the (e)MMC specific hw_reset code from core.c into mmc.c and call it from the new bus_ops member power_reset. This also lets us add code

power_reset is not a good name because it does not necessarily have anything to do with power. I am not sure why you don't stick with hw_reset.

Quoted 5 lines

for reseting SD cards as well.

Rename the mmc_hw_reset* functions into mmc_reset*, since what they now actually do depends on the device type (and it may be something else than doing a hw_reset).

Quoted 2 lines

I don't follow your reasoning about the rename. Cycling the power is a kind of hardware reset isn't it.

Since we finalize the reset by calling bus_ops->power_restore, I was looking for something symmetrical. Ulf mentioned perhaps extending bus_ops->power_save, but I couldn't find a reasonable way of doing this. Do you propose simply calling it bus_ops->hw_reset ?

Make the mmc_hw_reset routines more generic, so we can easily add a power cycle of SD cards as well. Also simplify the (e)MMC specific parts of the reset code.

As I don't have an eMMC device myself, much less one with a reset line, I'd be very happy if someone could help me test the code with an eMMC?

Johan Rudholm (4):
mmc: core: use mmc_send_status to check hw_reset
mmc: core: use mmc_power_up in hw_reset
mmc: core: make hw_reset generic
mmc: sd: add power_reset callback

 drivers/mmc/card/block.c    |    2 +-
 drivers/mmc/card/mmc_test.c |    5 +--
 drivers/mmc/core/core.c     |   73 ++++++++-----------------------------------
 drivers/mmc/core/core.h     |    4 ++
 drivers/mmc/core/mmc.c      |   40 +++++++++++++++++++++++
 drivers/mmc/core/sd.c       |   16 +++++++++
 include/linux/mmc/core.h    |    5 +--
 7 files changed, 77 insertions(+), 68 deletions(-)

--
1.7.2.5

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