[PATCH v3 0/3] mmc: core: hw_reset changes

[PATCH v3 0/3] 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?

Please have a look at the handling of bus_mode in
mmc_set_initial_state(), we set it to MMC_BUSMODE_PUSHPULL also when
powering off a device. If this is not OK, we'll just have to leave
bus_mode out of it.

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 (3):
  mmc: core: consistent handling of initial values
  mmc: core: turn hw_reset into a bus_ops
  mmc: sd: add hw_reset callback

 drivers/mmc/core/core.c |   99 ++++++++++++++++++-----------------------------
 drivers/mmc/core/core.h |    6 +++
 drivers/mmc/core/mmc.c  |   40 +++++++++++++++++++
 drivers/mmc/core/sd.c   |   13 ++++++
 4 files changed, 97 insertions(+), 61 deletions(-)

-- 
1.7.2.5

[PATCH v3 1/3] mmc: core: consistent handling of initial values

[Johan Rudholm]

mmc_do_hw_reset(), mmc_power_up() and mmc_power_off() all set similar
initial values for bus_mode, bus_width, chip_select and timing. Let's
make this handling simpler and more consistent by sticking them
together in a common function. This will introduce small changes in
behavior in the following places:

mmc_power_off():

  For SPI hosts, explicitly set bus_mode = MMC_BUSMODE_PUSHPULL and
  chip_select = MMC_CS_HIGH, before we left them as they were.

  For non-SPI hosts, set bus_mode = MMC_BUSMODE_PUSHPULL instead of
  MMC_BUSMODE_OPENDRAIN as before.

  These two changes should not be a problem since the device will be
  powered off anyway.

mmc_do_hw_reset():

  Always set bus_mode = MMC_BUSMODE_PUSHPULL, as required by SD/SDIO
  cards. MMC cards require MMC_BUSMODE_OPENDRAIN, but this is taken
  care of by mmc_init_card() and mmc_attach_mmc().

Signed-off-by: Johan Rudholm <johanru@axis.com>
---
 drivers/mmc/core/core.c |   47 ++++++++++++++++++++++-------------------------
 drivers/mmc/core/core.h |    1 +
 2 files changed, 23 insertions(+), 25 deletions(-)

diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index a32bea2..5bda29b 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -1099,6 +1099,22 @@ void mmc_set_bus_width(struct mmc_host *host, unsigned int width)
 	mmc_host_clk_release(host);
 }
 
+/*
+ * Set initial state after a power cycle or a hw_reset.
+ */
+void mmc_set_initial_state(struct mmc_host *host)
+{
+	if (mmc_host_is_spi(host))
+		host->ios.chip_select = MMC_CS_HIGH;
+	else
+		host->ios.chip_select = MMC_CS_DONTCARE;
+	host->ios.bus_mode = MMC_BUSMODE_PUSHPULL;
+	host->ios.bus_width = MMC_BUS_WIDTH_1;
+	host->ios.timing = MMC_TIMING_LEGACY;
+
+	mmc_set_ios(host);
+}
+
 /**
  * mmc_vdd_to_ocrbitnum - Convert a voltage to the OCR bit number
  * @vdd:	voltage (mV)
@@ -1537,15 +1553,9 @@ void mmc_power_up(struct mmc_host *host, u32 ocr)
 	mmc_host_clk_hold(host);
 
 	host->ios.vdd = fls(ocr) - 1;
-	if (mmc_host_is_spi(host))
-		host->ios.chip_select = MMC_CS_HIGH;
-	else
-		host->ios.chip_select = MMC_CS_DONTCARE;
-	host->ios.bus_mode = MMC_BUSMODE_PUSHPULL;
 	host->ios.power_mode = MMC_POWER_UP;
-	host->ios.bus_width = MMC_BUS_WIDTH_1;
-	host->ios.timing = MMC_TIMING_LEGACY;
-	mmc_set_ios(host);
+	/* Set initial state and call mmc_set_ios */
+	mmc_set_initial_state(host);
 
 	/* Try to set signal voltage to 3.3V but fall back to 1.8v or 1.2v */
 	if (__mmc_set_signal_voltage(host, MMC_SIGNAL_VOLTAGE_330) == 0)
@@ -1585,14 +1595,9 @@ void mmc_power_off(struct mmc_host *host)
 	host->ios.clock = 0;
 	host->ios.vdd = 0;
 
-	if (!mmc_host_is_spi(host)) {
-		host->ios.bus_mode = MMC_BUSMODE_OPENDRAIN;
-		host->ios.chip_select = MMC_CS_DONTCARE;
-	}
 	host->ios.power_mode = MMC_POWER_OFF;
-	host->ios.bus_width = MMC_BUS_WIDTH_1;
-	host->ios.timing = MMC_TIMING_LEGACY;
-	mmc_set_ios(host);
+	/* Set initial state and call mmc_set_ios */
+	mmc_set_initial_state(host);
 
 	/*
 	 * Some configurations, such as the 802.11 SDIO card in the OLPC
@@ -2278,16 +2283,8 @@ 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);
+	/* Set initial state and call mmc_set_ios */
+	mmc_set_initial_state(host);
 
 	mmc_host_clk_release(host);
 
diff --git a/drivers/mmc/core/core.h b/drivers/mmc/core/core.h
index 443a584..d76597c 100644
--- a/drivers/mmc/core/core.h
+++ b/drivers/mmc/core/core.h
@@ -49,6 +49,7 @@ void mmc_set_driver_type(struct mmc_host *host, unsigned int drv_type);
 void mmc_power_up(struct mmc_host *host, u32 ocr);
 void mmc_power_off(struct mmc_host *host);
 void mmc_power_cycle(struct mmc_host *host, u32 ocr);
+void mmc_set_initial_state(struct mmc_host *host);
 
 static inline void mmc_delay(unsigned int ms)
 {
-- 
1.7.2.5

[PATCH v3 2/3] mmc: core: turn hw_reset into a bus_ops

[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 hw_reset. This also lets us add code
for resetting SD cards as well.

Signed-off-by: Johan Rudholm <johanru@axis.com>
---
 drivers/mmc/core/core.c |   56 +++++++++++++++-------------------------------
 drivers/mmc/core/core.h |    5 ++++
 drivers/mmc/core/mmc.c  |   40 +++++++++++++++++++++++++++++++++
 3 files changed, 63 insertions(+), 38 deletions(-)

diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index 5bda29b..63ce146 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -2242,67 +2242,47 @@ 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);
-
+/* Reset card in a bus-specific way */
 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;
+	int ret;
 
-	if (!card)
+	if (!host->card)
 		return -EINVAL;
 
-	if (!mmc_can_reset(card))
+	if (!host->bus_ops || !host->bus_ops->hw_reset ||
+			host->bus_ops->hw_reset(host, MMC_HW_RESET_TEST))
 		return -EOPNOTSUPP;
 
-	mmc_host_clk_hold(host);
-	mmc_set_clock(host, host->f_init);
+	ret = host->bus_ops->hw_reset(host, check);
 
-	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;
-		}
-	}
-
-	/* Set initial state and call mmc_set_ios */
-	mmc_set_initial_state(host);
+	if (check == MMC_HW_RESET_TEST_CARD)
+		return ret;
 
-	mmc_host_clk_release(host);
+	pr_warn("%s: tried to reset card (status %d)\n",
+						mmc_hostname(host), ret);
 
 	return host->bus_ops->power_restore(host);
 }
 
 int mmc_hw_reset(struct mmc_host *host)
 {
-	return mmc_do_hw_reset(host, 0);
+	return mmc_do_hw_reset(host, MMC_HW_RESET_RESET);
 }
 EXPORT_SYMBOL(mmc_hw_reset);
 
 int mmc_hw_reset_check(struct mmc_host *host)
 {
-	return mmc_do_hw_reset(host, 1);
+	return mmc_do_hw_reset(host, MMC_HW_RESET_CHECK);
 }
 EXPORT_SYMBOL(mmc_hw_reset_check);
 
+int mmc_can_reset(struct mmc_card *card)
+{
+	return mmc_do_hw_reset(card->host, MMC_HW_RESET_TEST_CARD);
+}
+EXPORT_SYMBOL(mmc_can_reset);
+
 static int mmc_rescan_try_freq(struct mmc_host *host, unsigned freq)
 {
 	host->f_init = freq;
diff --git a/drivers/mmc/core/core.h b/drivers/mmc/core/core.h
index d76597c..f6e0a52 100644
--- a/drivers/mmc/core/core.h
+++ b/drivers/mmc/core/core.h
@@ -27,6 +27,11 @@ 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 *, int);
+#define MMC_HW_RESET_RESET	0
+#define MMC_HW_RESET_TEST	1
+#define MMC_HW_RESET_CHECK	2
+#define MMC_HW_RESET_TEST_CARD	3
 };
 
 void mmc_attach_bus(struct mmc_host *host, const struct mmc_bus_ops *ops);
diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
index 02ad792..7ffa3f2 100644
--- a/drivers/mmc/core/mmc.c
+++ b/drivers/mmc/core/mmc.c
@@ -1821,6 +1821,45 @@ static int mmc_power_restore(struct mmc_host *host)
 	return ret;
 }
 
+static int mmc_mmc_hw_reset(struct mmc_host *host, int test)
+{
+	struct mmc_card *card = host->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 -EOPNOTSUPP;
+
+	if (test == MMC_HW_RESET_TEST_CARD)
+		return 0;
+
+	if (!(host->caps & MMC_CAP_HW_RESET) || !host->ops->hw_reset)
+		return -EOPNOTSUPP;
+
+	if (test == MMC_HW_RESET_TEST)
+		return 0;
+
+	mmc_host_clk_hold(host);
+	mmc_set_clock(host, host->f_init);
+
+	host->ops->hw_reset(host);
+
+	if (test == MMC_HW_RESET_CHECK) {
+		u32 status;
+
+		if (!mmc_send_status(card, &status)) {
+			mmc_host_clk_release(host);
+			return -ENOSYS;
+		}
+	}
+
+	mmc_set_initial_state(host);
+
+	mmc_host_clk_release(host);
+
+	return 0;
+}
+
 static const struct mmc_bus_ops mmc_ops = {
 	.remove = mmc_remove,
 	.detect = mmc_detect,
@@ -1831,6 +1870,7 @@ 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,
 };
 
 /*
-- 
1.7.2.5

[PATCH v3 3/3] mmc: sd: add hw_reset callback

[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 <johanru@axis.com>
---
 drivers/mmc/core/sd.c |   13 +++++++++++++
 1 files changed, 13 insertions(+), 0 deletions(-)

diff --git a/drivers/mmc/core/sd.c b/drivers/mmc/core/sd.c
index d90a6de..a7fa124 100644
--- a/drivers/mmc/core/sd.c
+++ b/drivers/mmc/core/sd.c
@@ -1180,6 +1180,18 @@ static int mmc_sd_runtime_resume(struct mmc_host *host)
 	return 0;
 }
 
+static int mmc_sd_hw_reset(struct mmc_host *host, int test)
+{
+	struct mmc_card *card = host->card;
+
+	if (test == MMC_HW_RESET_TEST || test == MMC_HW_RESET_TEST_CARD)
+		return 0;
+
+	mmc_power_cycle(host, card->ocr);
+
+	return 0;
+}
+
 static int mmc_sd_power_restore(struct mmc_host *host)
 {
 	int ret;
@@ -1201,6 +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,
 };
 
 /*
-- 
1.7.2.5

Re: [PATCH v3 1/3] mmc: core: consistent handling of initial values

[Ulf Hansson]

On 6 November 2014 14:46, Johan Rudholm <johan.rudholm@axis.com> wrote:
> mmc_do_hw_reset(), mmc_power_up() and mmc_power_off() all set similar
> initial values for bus_mode, bus_width, chip_select and timing. Let's
> make this handling simpler and more consistent by sticking them
> together in a common function. This will introduce small changes in
> behavior in the following places:
>
> mmc_power_off():
>
>   For SPI hosts, explicitly set bus_mode = MMC_BUSMODE_PUSHPULL and
>   chip_select = MMC_CS_HIGH, before we left them as they were.
>
>   For non-SPI hosts, set bus_mode = MMC_BUSMODE_PUSHPULL instead of
>   MMC_BUSMODE_OPENDRAIN as before.
>
>   These two changes should not be a problem since the device will be
>   powered off anyway.
>
> mmc_do_hw_reset():
>
>   Always set bus_mode = MMC_BUSMODE_PUSHPULL, as required by SD/SDIO
>   cards. MMC cards require MMC_BUSMODE_OPENDRAIN, but this is taken
>   care of by mmc_init_card() and mmc_attach_mmc().
>
> Signed-off-by: Johan Rudholm <johanru@axis.com>

I decided to apply this one now for my next branch, thus we also get
some testing of it in linux-next.

If it turns out that it's causing issues, we need to come back to it.
For the rest of the patches I need some more time to review.

Thanks and kind regards
Uffe

> ---
>  drivers/mmc/core/core.c |   47 ++++++++++++++++++++++-------------------------
>  drivers/mmc/core/core.h |    1 +
>  2 files changed, 23 insertions(+), 25 deletions(-)
>
> diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
> index a32bea2..5bda29b 100644
> --- a/drivers/mmc/core/core.c
> +++ b/drivers/mmc/core/core.c
> @@ -1099,6 +1099,22 @@ void mmc_set_bus_width(struct mmc_host *host, unsigned int width)
>         mmc_host_clk_release(host);
>  }
>
> +/*
> + * Set initial state after a power cycle or a hw_reset.
> + */
> +void mmc_set_initial_state(struct mmc_host *host)
> +{
> +       if (mmc_host_is_spi(host))
> +               host->ios.chip_select = MMC_CS_HIGH;
> +       else
> +               host->ios.chip_select = MMC_CS_DONTCARE;
> +       host->ios.bus_mode = MMC_BUSMODE_PUSHPULL;
> +       host->ios.bus_width = MMC_BUS_WIDTH_1;
> +       host->ios.timing = MMC_TIMING_LEGACY;
> +
> +       mmc_set_ios(host);
> +}
> +
>  /**
>   * mmc_vdd_to_ocrbitnum - Convert a voltage to the OCR bit number
>   * @vdd:       voltage (mV)
> @@ -1537,15 +1553,9 @@ void mmc_power_up(struct mmc_host *host, u32 ocr)
>         mmc_host_clk_hold(host);
>
>         host->ios.vdd = fls(ocr) - 1;
> -       if (mmc_host_is_spi(host))
> -               host->ios.chip_select = MMC_CS_HIGH;
> -       else
> -               host->ios.chip_select = MMC_CS_DONTCARE;
> -       host->ios.bus_mode = MMC_BUSMODE_PUSHPULL;
>         host->ios.power_mode = MMC_POWER_UP;
> -       host->ios.bus_width = MMC_BUS_WIDTH_1;
> -       host->ios.timing = MMC_TIMING_LEGACY;
> -       mmc_set_ios(host);
> +       /* Set initial state and call mmc_set_ios */
> +       mmc_set_initial_state(host);
>
>         /* Try to set signal voltage to 3.3V but fall back to 1.8v or 1.2v */
>         if (__mmc_set_signal_voltage(host, MMC_SIGNAL_VOLTAGE_330) == 0)
> @@ -1585,14 +1595,9 @@ void mmc_power_off(struct mmc_host *host)
>         host->ios.clock = 0;
>         host->ios.vdd = 0;
>
> -       if (!mmc_host_is_spi(host)) {
> -               host->ios.bus_mode = MMC_BUSMODE_OPENDRAIN;
> -               host->ios.chip_select = MMC_CS_DONTCARE;
> -       }
>         host->ios.power_mode = MMC_POWER_OFF;
> -       host->ios.bus_width = MMC_BUS_WIDTH_1;
> -       host->ios.timing = MMC_TIMING_LEGACY;
> -       mmc_set_ios(host);
> +       /* Set initial state and call mmc_set_ios */
> +       mmc_set_initial_state(host);
>
>         /*
>          * Some configurations, such as the 802.11 SDIO card in the OLPC
> @@ -2278,16 +2283,8 @@ 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);
> +       /* Set initial state and call mmc_set_ios */
> +       mmc_set_initial_state(host);
>
>         mmc_host_clk_release(host);
>
> diff --git a/drivers/mmc/core/core.h b/drivers/mmc/core/core.h
> index 443a584..d76597c 100644
> --- a/drivers/mmc/core/core.h
> +++ b/drivers/mmc/core/core.h
> @@ -49,6 +49,7 @@ void mmc_set_driver_type(struct mmc_host *host, unsigned int drv_type);
>  void mmc_power_up(struct mmc_host *host, u32 ocr);
>  void mmc_power_off(struct mmc_host *host);
>  void mmc_power_cycle(struct mmc_host *host, u32 ocr);
> +void mmc_set_initial_state(struct mmc_host *host);
>
>  static inline void mmc_delay(unsigned int ms)
>  {
> --
> 1.7.2.5
>