[PATCH 0/4] mmc: core: hw_reset changes

[PATCH 0/4] mmc: core: hw_reset changes

[Johan Rudholm]

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

[PATCH 1/4] mmc: core: use mmc_send_status to check hw_reset

[Johan Rudholm]

Signed-off-by: Johan Rudholm <johanru@axis.com>
---
 drivers/mmc/core/core.c |   10 ++--------
 1 files changed, 2 insertions(+), 8 deletions(-)

diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index 7dc0c85..5d215ee 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -2265,15 +2265,9 @@ static int mmc_do_hw_reset(struct mmc_host *host, int check)
 
 	/* If the reset has happened, then a status command will fail */
 	if (check) {
-		struct mmc_command cmd = {0};
-		int err;
+		u32 status;
 
-		cmd.opcode = MMC_SEND_STATUS;
-		if (!mmc_host_is_spi(card->host))
-			cmd.arg = card->rca << 16;
-		cmd.flags = MMC_RSP_SPI_R2 | MMC_RSP_R1 | MMC_CMD_AC;
-		err = mmc_wait_for_cmd(card->host, &cmd, 0);
-		if (!err) {
+		if (!mmc_send_status(card, &status)) {
 			mmc_host_clk_release(host);
 			return -ENOSYS;
 		}
-- 
1.7.2.5

[PATCH 2/4] mmc: core: use mmc_power_up in hw_reset

[Johan Rudholm]

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 <johanru@axis.com>
---
 drivers/mmc/core/core.c |   11 +----------
 1 files changed, 1 insertions(+), 10 deletions(-)

diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index 5d215ee..d56e222 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -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);
 
-- 
1.7.2.5

Re: [PATCH 2/4] mmc: core: use mmc_power_up in hw_reset

[Adrian Hunter]

On 24/10/14 15:46, Johan Rudholm wrote:
> 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.

> to this function instead.
> 
> Signed-off-by: Johan Rudholm <johanru@axis.com>
> ---
>  drivers/mmc/core/core.c |   11 +----------
>  1 files changed, 1 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
> index 5d215ee..d56e222 100644
> --- a/drivers/mmc/core/core.c
> +++ b/drivers/mmc/core/core.c
> @@ -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);
>  
> 

Re: [PATCH 2/4] mmc: core: use mmc_power_up in hw_reset

[Johan Rudholm]

2014-11-03 10:21 GMT+01:00 Adrian Hunter <adrian.hunter@intel.com>:
> On 24/10/14 15:46, Johan Rudholm wrote:
>> 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.

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:

diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index 486cda8..941f631 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -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);

diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
index ac5192c..900133a 100644
--- a/drivers/mmc/core/mmc.c
+++ b/drivers/mmc/core/mmc.c
@@ -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;
diff --git a/drivers/mmc/core/sd.c b/drivers/mmc/core/sd.c
index 9ad46b2..d5b8ee7 100644
--- a/drivers/mmc/core/sd.c
+++ b/drivers/mmc/core/sd.c
@@ -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

Re: [PATCH 2/4] mmc: core: use mmc_power_up in hw_reset

[Adrian Hunter]

On 03/11/14 12:13, Johan Rudholm wrote:
> 2014-11-03 10:21 GMT+01:00 Adrian Hunter <adrian.hunter@intel.com>:
>> On 24/10/14 15:46, Johan Rudholm wrote:
>>> 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.
> 
> 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:

I would keep the concept of hw_reset separate from how that is
implemented i.e. whether it has anything to do with power.

> 
> diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
> index 486cda8..941f631 100644
> --- a/drivers/mmc/core/core.c
> +++ b/drivers/mmc/core/core.c
> @@ -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);
> 
> diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
> index ac5192c..900133a 100644
> --- a/drivers/mmc/core/mmc.c
> +++ b/drivers/mmc/core/mmc.c
> @@ -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;
> diff --git a/drivers/mmc/core/sd.c b/drivers/mmc/core/sd.c
> index 9ad46b2..d5b8ee7 100644
> --- a/drivers/mmc/core/sd.c
> +++ b/drivers/mmc/core/sd.c
> @@ -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
> 
> 

[PATCH 3/4] mmc: core: make hw_reset generic

[Johan Rudholm]

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 <johanru@axis.com>
---
 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(-)

diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c
index 452782b..8c4fa46 100644
--- a/drivers/mmc/card/block.c
+++ b/drivers/mmc/card/block.c
@@ -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);
diff --git a/drivers/mmc/card/mmc_test.c b/drivers/mmc/card/mmc_test.c
index 0c0fc52..599c683 100644
--- a/drivers/mmc/card/mmc_test.c
+++ b/drivers/mmc/card/mmc_test.c
@@ -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;
 }
 
diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index d56e222..486cda8 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -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)
 {
diff --git a/drivers/mmc/core/core.h b/drivers/mmc/core/core.h
index 443a584..6a0420b 100644
--- a/drivers/mmc/core/core.h
+++ b/drivers/mmc/core/core.h
@@ -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 *);
 };
diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
index 793c6f7..ac5192c 100644
--- a/drivers/mmc/core/mmc.c
+++ b/drivers/mmc/core/mmc.c
@@ -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,
 };
diff --git a/include/linux/mmc/core.h b/include/linux/mmc/core.h
index f206e29..4f7a76e 100644
--- a/include/linux/mmc/core.h
+++ b/include/linux/mmc/core.h
@@ -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);
-- 
1.7.2.5

Re: [PATCH 3/4] mmc: core: make hw_reset generic

[Adrian Hunter]

On 24/10/14 15:46, Johan Rudholm wrote:
> 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.

> 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.

> 
> Signed-off-by: Johan Rudholm <johanru@axis.com>
> ---
>  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(-)
> 
> diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c
> index 452782b..8c4fa46 100644
> --- a/drivers/mmc/card/block.c
> +++ b/drivers/mmc/card/block.c
> @@ -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);
> diff --git a/drivers/mmc/card/mmc_test.c b/drivers/mmc/card/mmc_test.c
> index 0c0fc52..599c683 100644
> --- a/drivers/mmc/card/mmc_test.c
> +++ b/drivers/mmc/card/mmc_test.c
> @@ -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;
>  }
>  
> diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
> index d56e222..486cda8 100644
> --- a/drivers/mmc/core/core.c
> +++ b/drivers/mmc/core/core.c
> @@ -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)
>  {
> diff --git a/drivers/mmc/core/core.h b/drivers/mmc/core/core.h
> index 443a584..6a0420b 100644
> --- a/drivers/mmc/core/core.h
> +++ b/drivers/mmc/core/core.h
> @@ -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 *);
>  };
> diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
> index 793c6f7..ac5192c 100644
> --- a/drivers/mmc/core/mmc.c
> +++ b/drivers/mmc/core/mmc.c
> @@ -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,
>  };
> diff --git a/include/linux/mmc/core.h b/include/linux/mmc/core.h
> index f206e29..4f7a76e 100644
> --- a/include/linux/mmc/core.h
> +++ b/include/linux/mmc/core.h
> @@ -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);
> 

Re: [PATCH 3/4] mmc: core: make hw_reset generic

[Johan Rudholm]

2014-11-03 10:20 GMT+01:00 Adrian Hunter <adrian.hunter@intel.com>:
> On 24/10/14 15:46, Johan Rudholm wrote:
>> 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.
>
>> 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.

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 ?

//Johan

Re: [PATCH 3/4] mmc: core: make hw_reset generic

[Adrian Hunter]

On 03/11/14 12:19, Johan Rudholm wrote:
> 2014-11-03 10:20 GMT+01:00 Adrian Hunter <adrian.hunter@intel.com>:
>> On 24/10/14 15:46, Johan Rudholm wrote:
>>> 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.
>>
>>> 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.
> 
> 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 ?

Yes

[PATCH 4/4] mmc: sd: add power_reset callback

[Johan Rudholm]

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

Signed-off-by: Johan Rudholm <johanru@axis.com>
---
 drivers/mmc/core/sd.c |   16 ++++++++++++++++
 1 files changed, 16 insertions(+), 0 deletions(-)

diff --git a/drivers/mmc/core/sd.c b/drivers/mmc/core/sd.c
index 0c44510..9ad46b2 100644
--- a/drivers/mmc/core/sd.c
+++ b/drivers/mmc/core/sd.c
@@ -1177,6 +1177,21 @@ static int mmc_sd_runtime_resume(struct mmc_host *host)
 	return 0;
 }
 
+static int mmc_sd_power_reset(struct mmc_host *host, int test)
+{
+	struct mmc_card *card = host->card;
+
+	if (!card)
+		return -EINVAL;
+
+	if (test == MMC_POWER_RESET_TEST)
+		return 0;
+
+	mmc_power_cycle(host, card->ocr);
+
+	return 0;
+}
+
 static int mmc_sd_power_restore(struct mmc_host *host)
 {
 	int ret;
@@ -1196,6 +1211,7 @@ static const struct mmc_bus_ops mmc_sd_ops = {
 	.suspend = mmc_sd_suspend,
 	.resume = mmc_sd_resume,
 	.power_restore = mmc_sd_power_restore,
+	.power_reset = mmc_sd_power_reset,
 	.alive = mmc_sd_alive,
 	.shutdown = mmc_sd_suspend,
 };
-- 
1.7.2.5

Re: [PATCH 0/4] mmc: core: hw_reset changes

[Johan Rudholm]

Hi all,

any comments on this patch set?

//Johan

2014-10-24 14:46 GMT+02:00 Johan Rudholm <johan.rudholm@axis.com>:
> 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
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-mmc" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html