[PATCH V7] mmc: core: Add Power Off Notify Feature eMMC 4.5

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This patch adds the support for power off notify feature
available in eMMC 4.5 devices.
        If the the host has support for this feature, then the
mmc core will notify it to the device by setting the
POWER_OFF_NOTIFICATION byte in the extended csd register
with a value 1(POWER_ON).
	For suspend mode short timeout is used, whereas for the 
normal poweroff long timeout is used.
        This patch is dependent on Seungwon Jeon's patch for
CMD6 timeout.

Signed-off-by: Girish K S <girish.shivananjappa@xxxxxxxxxx>
---
Changes in V2:
	Adds poweroff notification handling in suspend/normal
Changes in V4:
	Updated with review comments of Jeon
Changes in V5:
	This patch version fixes the problem with power off
	notify function, when called for the first time and
	card is not yet initialised.
Changes in V6:
	Fixes checkpatch errors. The patches are generated after
	rebasing to chris's mmc-next branch.
Changes in V7:
	Rebased to chris-mmc/mmc-next branch. merged to patches 
	to single patch.
 drivers/mmc/core/core.c  |   37 +++++++++++++++++++++++++++++++++++++
 drivers/mmc/core/mmc.c   |   22 ++++++++++++++++++++++
 drivers/mmc/host/sdhci.c |   10 ++++++++++
 include/linux/mmc/card.h |   21 +++++++++++++++++++++
 include/linux/mmc/host.h |    5 +++++
 include/linux/mmc/mmc.h  |    6 ++++++
 6 files changed, 101 insertions(+), 0 deletions(-)

diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index 9698d8a..5fb2120 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -1198,11 +1198,46 @@ static void mmc_power_up(struct mmc_host *host)
 
 void mmc_power_off(struct mmc_host *host)
 {
+	struct mmc_card *card;
+	unsigned int notify_type;
+	unsigned int timeout;
+	int err;
+
+	BUG_ON(!host);
+
 	mmc_host_clk_hold(host);
 
+	card = host->card;
 	host->ios.clock = 0;
 	host->ios.vdd = 0;
 
+	if (card != NULL && mmc_card_mmc(card) &&
+	    (mmc_card_powernotify_on(card))) {
+
+		if (host->power_notify_type == MMC_HOST_PW_NOTIFY_SHORT) {
+			notify_type = EXT_CSD_POWER_OFF_SHORT;
+			timeout = card->ext_csd.generic_cmd6_time;
+			mmc_card_set_powernotify_short(card);
+		} else {
+			notify_type = EXT_CSD_POWER_OFF_LONG;
+			timeout = card->ext_csd.power_off_longtime;
+			mmc_card_set_powernotify_long(card);
+		}
+
+		err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
+				 EXT_CSD_POWER_OFF_NOTIFICATION,
+				 notify_type, timeout);
+
+		if (err && err != -EBADMSG)
+			pr_err("Device failed to respond "
+			       "within %d poweroff time."
+			       "forcefully powering down"
+			       "the device\n", timeout);
+
+		/* Set the card state to no notification after the poweroff */
+		mmc_card_set_powernotify_off(card);
+	}
+
 	/*
 	 * Reset ocr mask to be the highest possible voltage supported for
 	 * this mmc host. This value will be used at next power up.
@@ -2194,6 +2230,7 @@ int mmc_pm_notify(struct notifier_block *notify_block,
 
 		spin_lock_irqsave(&host->lock, flags);
 		host->rescan_disable = 1;
+		host->power_notify_type = MMC_HOST_PW_NOTIFY_SHORT;
 		spin_unlock_irqrestore(&host->lock, flags);
 		cancel_delayed_work_sync(&host->detect);
 
@@ -2217,6 +2254,7 @@ int mmc_pm_notify(struct notifier_block *notify_block,
 
 		spin_lock_irqsave(&host->lock, flags);
 		host->rescan_disable = 0;
+		host->power_notify_type = MMC_HOST_PW_NOTIFY_LONG;
 		spin_unlock_irqrestore(&host->lock, flags);
 		mmc_detect_change(host, 0);
 
diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
index f28aa4f..25ba7f5 100644
--- a/drivers/mmc/core/mmc.c
+++ b/drivers/mmc/core/mmc.c
@@ -447,6 +447,11 @@ static int mmc_read_ext_csd(struct mmc_card *card, u8 *ext_csd)
 	else
 		card->erased_byte = 0x0;
 
+	if (card->ext_csd.rev >= 6) {
+		card->ext_csd.power_off_longtime = 10 *
+			ext_csd[EXT_CSD_POWER_OFF_LONG_TIME];
+	}
+
 out:
 	return err;
 }
@@ -829,6 +834,23 @@ static int mmc_init_card(struct mmc_host *host, u32 ocr,
 	}
 
 	/*
+	 * If the host supports the power_off_notify capability then
+	 * set the notification byte in the ext_csd register of device
+	 */
+	if (host->caps2 & MMC_CAP_POWEROFF_NOTIFY &&
+	    (mmc_card_powernotify_off(card))) {
+		err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
+				 EXT_CSD_POWER_OFF_NOTIFICATION,
+				 EXT_CSD_POWER_ON,
+				 card->ext_csd.generic_cmd6_time);
+		if (err && err != -EBADMSG)
+			goto free_card;
+	}
+
+	if (!err)
+		mmc_card_set_powernotify_on(card);
+
+	/*
 	 * Activate high speed (if supported)
 	 */
 	if (card->ext_csd.hs_max_dtr != 0) {
diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index 4220133..2818238 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -2599,6 +2599,16 @@ int sdhci_add_host(struct sdhci_host *host)
 	if (caps[1] & SDHCI_DRIVER_TYPE_D)
 		mmc->caps |= MMC_CAP_DRIVER_TYPE_D;
 
+	/*
+	 * If Notify capability is enabled and
+	 * notify type is not initialised by host, set default to
+	 * long power off notify timeout value
+	 */
+	if (mmc->caps2 & MMC_CAP_POWEROFF_NOTIFY)
+		mmc->power_notify_type = MMC_HOST_PW_NOTIFY_SHORT;
+	else
+		mmc->power_notify_type = MMC_HOST_PW_NOTIFY_NONE;
+
 	/* Initial value for re-tuning timer count */
 	host->tuning_count = (caps[1] & SDHCI_RETUNING_TIMER_COUNT_MASK) >>
 			      SDHCI_RETUNING_TIMER_COUNT_SHIFT;
diff --git a/include/linux/mmc/card.h b/include/linux/mmc/card.h
index 15e5ce2..d6f8c85 100644
--- a/include/linux/mmc/card.h
+++ b/include/linux/mmc/card.h
@@ -53,6 +53,8 @@ struct mmc_ext_csd {
 	u8			rst_n_function;
 	unsigned int		part_time;		/* Units: ms */
 	unsigned int		sa_timeout;		/* Units: 100ns */
+	unsigned int            generic_cmd6_time;      /* Units: ms */
+	unsigned int            power_off_longtime;     /* Units: ms */
 	unsigned int		hs_max_dtr;
 	unsigned int		sectors;
 	unsigned int		card_type;
@@ -192,6 +194,11 @@ struct mmc_card {
 #define MMC_QUIRK_BLK_NO_CMD23	(1<<7)		/* Avoid CMD23 for regular multiblock */
 #define MMC_QUIRK_BROKEN_BYTE_MODE_512 (1<<8)	/* Avoid sending 512 bytes in */
 						/* byte mode */
+	unsigned int    poweroff_notify_state;	/* eMMC4.5 notify feature */
+#define MMC_NO_POWER_NOTIFICATION	0
+#define MMC_POWERED_ON			1
+#define MMC_POWEROFF_SHORT		2
+#define MMC_POWEROFF_LONG		3
 
 	unsigned int		erase_size;	/* erase size in sectors */
  	unsigned int		erase_shift;	/* if erase unit is power 2 */
@@ -329,6 +336,20 @@ static inline void __maybe_unused remove_quirk(struct mmc_card *card, int data)
 #define mmc_sd_card_set_uhs(c) ((c)->state |= MMC_STATE_ULTRAHIGHSPEED)
 #define mmc_card_set_ext_capacity(c) ((c)->state |= MMC_CARD_SDXC)
 
+#define mmc_card_powernotify_on(c)     \
+		 ((c)->poweroff_notify_state == MMC_POWERED_ON)
+#define mmc_card_powernotify_off(c)    \
+		 ((c)->poweroff_notify_state == MMC_NO_POWER_NOTIFICATION)
+
+#define mmc_card_set_powernotify_off(c)    \
+		 ((c)->poweroff_notify_state = MMC_NO_POWER_NOTIFICATION)
+#define mmc_card_set_powernotify_on(c) \
+		 ((c)->poweroff_notify_state = MMC_POWERED_ON)
+#define mmc_card_set_powernotify_short(c)  \
+		 ((c)->poweroff_notify_state = MMC_POWEROFF_SHORT)
+#define mmc_card_set_powernotify_long(c)   \
+		 ((c)->poweroff_notify_state = MMC_POWEROFF_LONG)
+
 /*
  * Quirk add/remove for MMC products.
  */
diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
index f62ffa2..b711a00 100644
--- a/include/linux/mmc/host.h
+++ b/include/linux/mmc/host.h
@@ -245,8 +245,13 @@ struct mmc_host {
 #define MMC_CAP_HS200_1_8V_SDR	(1 << 2)	/* can support */
 #define MMC_CAP_HS200_1_2V_SDR	(1 << 3)	/* can support */
 #define MMC_CAP_HIGHSPEED_200	(1 << 4)	/* Can do MMC HS200 timing */
+#define MMC_CAP_POWEROFF_NOTIFY	(1 << 31)	/* Notify poweroff supported */
 
 	mmc_pm_flag_t		pm_caps;	/* supported pm features */
+	unsigned int        power_notify_type;
+#define MMC_HOST_PW_NOTIFY_NONE		0
+#define MMC_HOST_PW_NOTIFY_SHORT	1
+#define MMC_HOST_PW_NOTIFY_LONG		2
 
 #ifdef CONFIG_MMC_CLKGATE
 	int			clk_requests;	/* internal reference counter */
diff --git a/include/linux/mmc/mmc.h b/include/linux/mmc/mmc.h
index 3f2e210..944c99b 100644
--- a/include/linux/mmc/mmc.h
+++ b/include/linux/mmc/mmc.h
@@ -271,6 +271,7 @@ struct _mmc_csd {
  * EXT_CSD fields
  */
 
+#define EXT_CSD_POWER_OFF_NOTIFICATION	34	/* R/W */
 #define EXT_CSD_PARTITION_ATTRIBUTE	156	/* R/W */
 #define EXT_CSD_PARTITION_SUPPORT	160	/* RO */
 #define EXT_CSD_RST_N_FUNCTION		162	/* R/W */
@@ -348,6 +349,11 @@ struct _mmc_csd {
 #define EXT_CSD_RST_N_EN_MASK	0x3
 #define EXT_CSD_RST_N_ENABLED	1	/* RST_n is enabled on card */
 
+#define EXT_CSD_NO_POWER_NOTIFICATION	0
+#define EXT_CSD_POWER_ON		1
+#define EXT_CSD_POWER_OFF_SHORT		2
+#define EXT_CSD_POWER_OFF_LONG		3
+
 #define EXT_CSD_PWR_CL_8BIT_MASK	0xF0	/* 8 bit PWR CLS */
 #define EXT_CSD_PWR_CL_4BIT_MASK	0x0F	/* 8 bit PWR CLS */
 #define EXT_CSD_PWR_CL_8BIT_SHIFT	4
-- 
1.7.1

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