mmc: core: hw_reset changes

PATCH Superseded Johan Rudholm 2 participants 5 messages Jan 9, 2015 – Jan 12, 2015 MMC, SD and SDIO

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Johan Rudholm

author

2015-01-09 11:08 UTC #0 lore raw

v6 cover mmc: core: hw_reset changes

Make the mmc_hw_reset routine more generic, by putting the (e)MMC- specific stuff in the new bus_ops->hw_reset in mmc.c. Add a bus_ops->hw_reset for SD cards, allowing them to be restarted when errors occur.

Always check if the reset was sucessful and propagate this to the caller.

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?

v6:
- Always perform the mmc_send_status reset check, which allows us to have only one interface to the card reset functions
- Because of this, add the bus_ops->hw_reset to sd.c instead of falling back to a power_cycle

v5:
- Move the mmc_test-specific code to mmc_test.c
- Fall back to a power_cycle if the bus_ops->hw_reset is missing
- Because of this, skip the bus_ops->hw_reset in sd.c

v4:
- Rebase onto next

v3:
- Keep mmc_can_reset
- Always set bus_mode = MMC_BUSMODE_PUSHPULL in mmc_set_initial_state()

v2:
- Call the new bus_ops member hw_reset instead of power_reset
- Create mmc_set_initial_state and call it from mmc_mmc_hw_reset instead of mmc_power_up
- Keep "mmc_hw_reset" naming

Johan Rudholm (2):
mmc: core: refactor the hw_reset routines
mmc: sd: add hw_reset callback

 drivers/mmc/card/mmc_test.c |   18 ++++-------
 drivers/mmc/core/core.c     |   70 +++++++++++++++----------------------------
 drivers/mmc/core/core.h     |    1 +
 drivers/mmc/core/mmc.c      |   32 +++++++++++++++++++
 drivers/mmc/core/sd.c       |    7 ++++
 include/linux/mmc/core.h    |    1 -
 6 files changed, 71 insertions(+), 58 deletions(-)

Signature · 1 line

1.7.2.5

Johan Rudholm

author

2015-01-09 11:08 UTC #1 lore raw

PATCH v6 1/2 mmc: core: refactor the hw_reset routines

Move the (e)MMC specific hw_reset code from core.c into mmc.c Call the code from the new bus_ops member hw_reset. This also allows for adding a SD card specific reset procedure.

Always check if the card is alive after a successful reset. This allows us to remove mmc_hw_reset_check(), leaving mmc_hw_reset() as the only card reset interface. This also informs any callers, for instance the block layer, if a reset was sucessful or not.

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

---
 drivers/mmc/card/mmc_test.c |   18 ++++-------
 drivers/mmc/core/core.c     |   70 +++++++++++++++----------------------------
 drivers/mmc/core/core.h     |    1 +
 drivers/mmc/core/mmc.c      |   32 +++++++++++++++++++
 include/linux/mmc/core.h    |    1 -
 5 files changed, 64 insertions(+), 58 deletions(-)

drivers/mmc/card/mmc_test.c +7 ~~-11~~

index 0a7430f..7dac469 100644
@@ -2342,20 +2342,16 @@ 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);
+	if (!mmc_card_mmc(card) || !mmc_can_reset(card))
+		return RESULT_UNSUP_CARD;
+
+	err = mmc_hw_reset(host);
 	if (!err)
 		return RESULT_OK;
+	else if (err == -EOPNOTSUPP)
+		return RESULT_UNSUP_HOST;
 
-	if (err == -ENOSYS)
-		return RESULT_FAIL;
-
-	if (err != -EOPNOTSUPP)
-		return err;
-
-	if (!mmc_can_reset(card))
-		return RESULT_UNSUP_CARD;
-
-	return RESULT_UNSUP_HOST;
+	return RESULT_FAIL;
 }
 
 static const struct mmc_test_case mmc_test_cases[] = {

drivers/mmc/core/core.c +24 ~~-46~~

91 lines not on this page · raw message

drivers/mmc/core/core.h +1 -0

index b528c0e..4d1ee8a 100644
@@ -27,6 +27,7 @@ struct mmc_bus_ops {
 	int (*power_restore)(struct mmc_host *);
 	int (*alive)(struct mmc_host *);
 	int (*shutdown)(struct mmc_host *);
+	int (*hw_reset)(struct mmc_host *);
 };
 
 void mmc_attach_bus(struct mmc_host *host, const struct mmc_bus_ops *ops);

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

index 0b8ec87..f64a53e 100644
@@ -1795,6 +1795,37 @@ static int mmc_power_restore(struct mmc_host *host)
 	return ret;
 }
 
+int mmc_can_reset(struct mmc_card *card)
+{
+	u8 rst_n_function;
+
+	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_mmc_hw_reset(struct mmc_host *host)
+{
+	struct mmc_card *card = host->card;
+
+	if (!(host->caps & MMC_CAP_HW_RESET) || !host->ops->hw_reset)
+		return -EOPNOTSUPP;
+
+	if (!mmc_can_reset(card))
+		return -EOPNOTSUPP;
+
+	mmc_host_clk_hold(host);
+	mmc_set_clock(host, host->f_init);
+
+	host->ops->hw_reset(host);
+
+	mmc_host_clk_release(host);
+
+	return 0;
+}
+
 static const struct mmc_bus_ops mmc_ops = {
 	.remove = mmc_remove,
 	.detect = mmc_detect,

@@ -1805,6 +1836,7 @@ static const struct mmc_bus_ops mmc_ops = {
 	.power_restore = mmc_power_restore,
 	.alive = mmc_alive,
 	.shutdown = mmc_shutdown,
+	.hw_reset = mmc_mmc_hw_reset,
 };
 
 /*

include/linux/mmc/core.h +0 -1

index cb2b040..160448f 100644
@@ -182,7 +182,6 @@ 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 void mmc_set_data_timeout(struct mmc_data *, const struct mmc_card *);

Signature · 1 line

1.7.2.5

Ulf Hansson

2015-01-12 12:55 UTC #2 lore raw

Re: [PATCH v6 1/2] mmc: core: refactor the hw_reset routines

Quoted 113 lines · Johan Rudholm

Move the (e)MMC specific hw_reset code from core.c into mmc.c Call the code from the new bus_ops member hw_reset. This also allows for adding a SD card specific reset procedure.

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

---
 drivers/mmc/card/mmc_test.c |   18 ++++-------
 drivers/mmc/core/core.c     |   70 +++++++++++++++----------------------------
 drivers/mmc/core/core.h     |    1 +
 drivers/mmc/core/mmc.c      |   32 +++++++++++++++++++
 include/linux/mmc/core.h    |    1 -
 5 files changed, 64 insertions(+), 58 deletions(-)

drivers/mmc/card/mmc_test.c +7 ~~-11~~

index 0a7430f..7dac469 100644
@@ -2342,20 +2342,16 @@ 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);
+       if (!mmc_card_mmc(card) || !mmc_can_reset(card))
+               return RESULT_UNSUP_CARD;
+
+       err = mmc_hw_reset(host);
        if (!err)
                return RESULT_OK;
+       else if (err == -EOPNOTSUPP)
+               return RESULT_UNSUP_HOST;
 
-       if (err == -ENOSYS)
-               return RESULT_FAIL;
-
-       if (err != -EOPNOTSUPP)
-               return err;
-
-       if (!mmc_can_reset(card))
-               return RESULT_UNSUP_CARD;
-
-       return RESULT_UNSUP_HOST;
+       return RESULT_FAIL;
 }
 
 static const struct mmc_test_case mmc_test_cases[] = {

drivers/mmc/core/core.c +15 ~~-32~~

index d3bfbdf..8598287 100644
@@ -2273,67 +2273,45 @@ static void mmc_hw_reset_for_init(struct mmc_host *host)
        mmc_host_clk_release(host);
 }
 
-int mmc_can_reset(struct mmc_card *card)
-{
-       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)
+int mmc_hw_reset(struct mmc_host *host)
 {
-       struct mmc_card *card = host->card;
-
-       if (!(host->caps & MMC_CAP_HW_RESET) || !host->ops->hw_reset)
-               return -EOPNOTSUPP;
+       int ret = 0;
+       int card_alive = 0;
+       u32 status;
 
-       if (!card)
+       if (!host->card)
                return -EINVAL;
 
-       if (!mmc_can_reset(card))
-               return -EOPNOTSUPP;
-
-       mmc_host_clk_hold(host);
-       mmc_set_clock(host, host->f_init);
+       mmc_bus_get(host);
+       if (!host->bus_ops || host->bus_dead || !host->bus_ops->hw_reset) {
+               ret = -EOPNOTSUPP;
+               goto out;
+       }
 
-       host->ops->hw_reset(host);
+       ret = host->bus_ops->hw_reset(host);
+       if (ret)
+               goto out;
 
        /* If the reset has happened, then a status command will fail */
-       if (check) {
-               u32 status;
+       if (!mmc_send_status(host->card, &status))
+               card_alive = 1;
 
-               if (!mmc_send_status(card, &status)) {
-                       mmc_host_clk_release(host);
-                       return -ENOSYS;
-               }
-       }

drivers/mmc/core/core.c static void mmc_hw_reset_for_init(struct mmc_host *host) · line 2322

Quoted 10 lines

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

+       pr_warn("%s: tried to reset card (%s)\n", mmc_hostname(host),
+                                       card_alive ? "failed" : "ok");
 
        /* Set initial state and call mmc_set_ios */
        mmc_set_initial_state(host);
+       ret = host->bus_ops->power_restore(host);
 
-       mmc_host_clk_release(host);
-
-       return host->bus_ops->power_restore(host);

I would like you to move the mmc_send_status() and onwards code in this function, into the mmc specific ->hw_reset() callback.

In that way, mmc/sd/sdio can separately decide if the mmc_send_status() is needed and we also can remove two users (sd/mmc) of the ->power_restore() callback.

Quoted 28 lines

drivers/mmc/core/core.c +6 ~~-11~~

-}
-
-int mmc_hw_reset(struct mmc_host *host)
-{
-       return mmc_do_hw_reset(host, 0);
+out:
+       mmc_bus_put(host);
+       if (card_alive)
+               return -ENOSYS;
+       else
+               return ret;
 }
 EXPORT_SYMBOL(mmc_hw_reset);
 
-int mmc_hw_reset_check(struct mmc_host *host)
-{
-       return mmc_do_hw_reset(host, 1);
-}
-EXPORT_SYMBOL(mmc_hw_reset_check);
-
 static int mmc_rescan_try_freq(struct mmc_host *host, unsigned freq)
 {
        host->f_init = freq;

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

index b528c0e..4d1ee8a 100644

drivers/mmc/core/core.h struct mmc_bus_ops { · line 30

Quoted 4 lines

drivers/mmc/core/core.h +1 -0

@@ -27,6 +27,7 @@ struct mmc_bus_ops {
        int (*power_restore)(struct mmc_host *);
        int (*alive)(struct mmc_host *);
        int (*shutdown)(struct mmc_host *);
+       int (*hw_reset)(struct mmc_host *);

->Please rename to reset()

Quoted 13 lines

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

 };
 
 void mmc_attach_bus(struct mmc_host *host, const struct mmc_bus_ops *ops);

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

index 0b8ec87..f64a53e 100644
@@ -1795,6 +1795,37 @@ static int mmc_power_restore(struct mmc_host *host)
        return ret;
 }
 
+int mmc_can_reset(struct mmc_card *card)
+{

drivers/mmc/core/mmc.c static int mmc_power_restore(struct mmc_host *host) · line 1809

Quoted 10 lines

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

+       u8 rst_n_function;
+
+       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_mmc_hw_reset(struct mmc_host *host)

Please rename to mmc_reset()

Quoted 43 lines

drivers/mmc/core/mmc.c +20 -0

+{
+       struct mmc_card *card = host->card;
+
+       if (!(host->caps & MMC_CAP_HW_RESET) || !host->ops->hw_reset)
+               return -EOPNOTSUPP;
+
+       if (!mmc_can_reset(card))
+               return -EOPNOTSUPP;
+
+       mmc_host_clk_hold(host);
+       mmc_set_clock(host, host->f_init);
+
+       host->ops->hw_reset(host);
+
+       mmc_host_clk_release(host);
+
+       return 0;
+}
+
 static const struct mmc_bus_ops mmc_ops = {
        .remove = mmc_remove,
        .detect = mmc_detect,

@@ -1805,6 +1836,7 @@ static const struct mmc_bus_ops mmc_ops = {
        .power_restore = mmc_power_restore,
        .alive = mmc_alive,
        .shutdown = mmc_shutdown,
+       .hw_reset = mmc_mmc_hw_reset,
 };
 
 /*

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

index cb2b040..160448f 100644
@@ -182,7 +182,6 @@ 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 void mmc_set_data_timeout(struct mmc_data *, const struct mmc_card *);
--

Quoted 2 lines

1.7.2.5

I am overall very happy with this approach. Nice work Johan!

Kind regards
Uffe

Johan Rudholm

author

2015-01-12 14:38 UTC #3 lore raw

Re: [PATCH v6 1/2] mmc: core: refactor the hw_reset routines

2015-01-12 13:55 GMT+01:00 Ulf Hansson <[email protected]>:

Quoted 128 lines · Johan Rudholm

Quoted 113 lines

Move the (e)MMC specific hw_reset code from core.c into mmc.c Call the code from the new bus_ops member hw_reset. This also allows for adding a SD card specific reset procedure.

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

---
 drivers/mmc/card/mmc_test.c |   18 ++++-------
 drivers/mmc/core/core.c     |   70 +++++++++++++++----------------------------
 drivers/mmc/core/core.h     |    1 +
 drivers/mmc/core/mmc.c      |   32 +++++++++++++++++++
 include/linux/mmc/core.h    |    1 -
 5 files changed, 64 insertions(+), 58 deletions(-)

drivers/mmc/card/mmc_test.c +7 ~~-11~~

index 0a7430f..7dac469 100644
@@ -2342,20 +2342,16 @@ 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);
+       if (!mmc_card_mmc(card) || !mmc_can_reset(card))
+               return RESULT_UNSUP_CARD;
+
+       err = mmc_hw_reset(host);
        if (!err)
                return RESULT_OK;
+       else if (err == -EOPNOTSUPP)
+               return RESULT_UNSUP_HOST;
 
-       if (err == -ENOSYS)
-               return RESULT_FAIL;
-
-       if (err != -EOPNOTSUPP)
-               return err;
-
-       if (!mmc_can_reset(card))
-               return RESULT_UNSUP_CARD;
-
-       return RESULT_UNSUP_HOST;
+       return RESULT_FAIL;
 }
 
 static const struct mmc_test_case mmc_test_cases[] = {

drivers/mmc/core/core.c +15 ~~-32~~

index d3bfbdf..8598287 100644
@@ -2273,67 +2273,45 @@ static void mmc_hw_reset_for_init(struct mmc_host *host)
        mmc_host_clk_release(host);
 }
 
-int mmc_can_reset(struct mmc_card *card)
-{
-       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)
+int mmc_hw_reset(struct mmc_host *host)
 {
-       struct mmc_card *card = host->card;
-
-       if (!(host->caps & MMC_CAP_HW_RESET) || !host->ops->hw_reset)
-               return -EOPNOTSUPP;
+       int ret = 0;
+       int card_alive = 0;
+       u32 status;
 
-       if (!card)
+       if (!host->card)
                return -EINVAL;
 
-       if (!mmc_can_reset(card))
-               return -EOPNOTSUPP;
-
-       mmc_host_clk_hold(host);
-       mmc_set_clock(host, host->f_init);
+       mmc_bus_get(host);
+       if (!host->bus_ops || host->bus_dead || !host->bus_ops->hw_reset) {
+               ret = -EOPNOTSUPP;
+               goto out;
+       }
 
-       host->ops->hw_reset(host);
+       ret = host->bus_ops->hw_reset(host);
+       if (ret)
+               goto out;
 
        /* If the reset has happened, then a status command will fail */
-       if (check) {
-               u32 status;
+       if (!mmc_send_status(host->card, &status))
+               card_alive = 1;
 
-               if (!mmc_send_status(card, &status)) {
-                       mmc_host_clk_release(host);
-                       return -ENOSYS;
-               }
-       }

drivers/mmc/core/core.c static void mmc_hw_reset_for_init(struct mmc_host *host) · line 2322

Quoted 10 lines

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

+       pr_warn("%s: tried to reset card (%s)\n", mmc_hostname(host),
+                                       card_alive ? "failed" : "ok");
 
        /* Set initial state and call mmc_set_ios */
        mmc_set_initial_state(host);
+       ret = host->bus_ops->power_restore(host);
 
-       mmc_host_clk_release(host);
-
-       return host->bus_ops->power_restore(host);

I would like you to move the mmc_send_status() and onwards code in this function, into the mmc specific ->hw_reset() callback.

Quoted 3 lines

In that way, mmc/sd/sdio can separately decide if the mmc_send_status() is needed and we also can remove two users (sd/mmc) of the ->power_restore() callback.

Good idea, this makes the core.c code cleaner. I've decided to put the removal of mmc_hw_reset_check() into a separate patch, to make it easier to see what's happened.

Quoted 26 lines

drivers/mmc/core/core.c +6 ~~-11~~

-}
-
-int mmc_hw_reset(struct mmc_host *host)
-{
-       return mmc_do_hw_reset(host, 0);
+out:
+       mmc_bus_put(host);
+       if (card_alive)
+               return -ENOSYS;
+       else
+               return ret;
 }
 EXPORT_SYMBOL(mmc_hw_reset);
 
-int mmc_hw_reset_check(struct mmc_host *host)
-{
-       return mmc_do_hw_reset(host, 1);
-}
-EXPORT_SYMBOL(mmc_hw_reset_check);
-
 static int mmc_rescan_try_freq(struct mmc_host *host, unsigned freq)
 {
        host->f_init = freq;

drivers/mmc/core/core.h +0 -1

index b528c0e..4d1ee8a 100644
--- a/drivers/mmc/core/core.h

Quoted 8 lines

drivers/mmc/core/core.h struct mmc_bus_ops { · line 30
Quoted 6 lines
+++ b/drivers/mmc/core/core.h
drivers/mmc/core/core.h +1 -0
@@ -27,6 +27,7 @@ struct mmc_bus_ops {
        int (*power_restore)(struct mmc_host *);
        int (*alive)(struct mmc_host *);
        int (*shutdown)(struct mmc_host *);
+       int (*hw_reset)(struct mmc_host *);
->Please rename to reset()

Ok.

Quoted 11 lines

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

 };
 
 void mmc_attach_bus(struct mmc_host *host, const struct mmc_bus_ops *ops);

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

index 0b8ec87..f64a53e 100644
@@ -1795,6 +1795,37 @@ static int mmc_power_restore(struct mmc_host *host)
        return ret;
 }

Quoted 14 lines

drivers/mmc/core/mmc.c static int mmc_power_restore(struct mmc_host *host) · line 1809

Quoted 12 lines

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

+int mmc_can_reset(struct mmc_card *card)
+{
+       u8 rst_n_function;
+
+       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_mmc_hw_reset(struct mmc_host *host)

Please rename to mmc_reset()

Ok.

Quoted 41 lines

drivers/mmc/core/mmc.c +20 -0

+{
+       struct mmc_card *card = host->card;
+
+       if (!(host->caps & MMC_CAP_HW_RESET) || !host->ops->hw_reset)
+               return -EOPNOTSUPP;
+
+       if (!mmc_can_reset(card))
+               return -EOPNOTSUPP;
+
+       mmc_host_clk_hold(host);
+       mmc_set_clock(host, host->f_init);
+
+       host->ops->hw_reset(host);
+
+       mmc_host_clk_release(host);
+
+       return 0;
+}
+
 static const struct mmc_bus_ops mmc_ops = {
        .remove = mmc_remove,
        .detect = mmc_detect,

@@ -1805,6 +1836,7 @@ static const struct mmc_bus_ops mmc_ops = {
        .power_restore = mmc_power_restore,
        .alive = mmc_alive,
        .shutdown = mmc_shutdown,
+       .hw_reset = mmc_mmc_hw_reset,
 };
 
 /*

include/linux/mmc/core.h +0 -1

index cb2b040..160448f 100644
@@ -182,7 +182,6 @@ 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);

Quoted 6 lines

Quoted 4 lines
include/linux/mmc/core.h +0 -1
 extern void mmc_set_data_timeout(struct mmc_data *, const struct mmc_card *);
--
1.7.2.5
I am overall very happy with this approach. Nice work Johan!

Thank you, and thank you for the detailed review work!

//Johan

Johan Rudholm

author

2015-01-09 11:08 UTC #4 lore raw

PATCH v6 2/2 mmc: sd: add hw_reset callback

In reply to Johan Rudholm

Enable power cycle and re-initialization of SD cards via the hw_reset bus_ops. Power cycling a buggy SD card sometimes helps it get back on track.

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

---
 drivers/mmc/core/sd.c |    7 +++++++
 1 files changed, 7 insertions(+), 0 deletions(-)

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

index 29fccdc..1228ef7 100644
@@ -1197,6 +1197,12 @@ static int mmc_sd_power_restore(struct mmc_host *host)
 	return ret;
 }
 
+static int mmc_sd_hw_reset(struct mmc_host *host)
+{
+	mmc_power_cycle(host, host->card->ocr);
+	return 0;
+}
+
 static const struct mmc_bus_ops mmc_sd_ops = {
 	.remove = mmc_sd_remove,
 	.detect = mmc_sd_detect,

@@ -1207,6 +1213,7 @@ static const struct mmc_bus_ops mmc_sd_ops = {
 	.power_restore = mmc_sd_power_restore,
 	.alive = mmc_sd_alive,
 	.shutdown = mmc_sd_suspend,
+	.hw_reset = mmc_sd_hw_reset,
 };
 
 /*

Signature · 1 line

1.7.2.5