[PATCH] mmc: sleep notification

[Avi Shchislowski <avi.shchislowski@sandisk.com>]

This patch is implements the new additional state of
Power_Off_Notification – SLEEP_NOTIFICATION.
Until now, the implementation of Power_Off_Notification
supported only three modes – POWERED_ON (0x01),
POWER_OFF_SHORT (0x02) and POWER_OFF_LONG (0x03).

As part of eMMC5.0 before moving to Sleep state hosts may set the
POWER_OFF_NOTIFICATION byte to SLEEP_NOTIFICATION (0x04).
After setting SLEEP_NOTIFICATION, host should wait for
the busy line to be de-asserted.
The max timeout allowed for busy line de-assertion defined
in SLEEP_NOTIFICATION_TIME byte in EXT_CSD [216].
HPI may interrupt the SLEEP_NOTIFICATION operation.
In that case POWER_OFF_NOTIFICATION byte will restore to POWERED_ON.

Signed-off-by: Alex Lemberg <alex.lemberg@sandisk.com>
Signed-off-by: Avi Shchislowski <avi.shchislowski@sandisk.com>
---
 drivers/mmc/card/block.c |   19 +++++-
 drivers/mmc/core/core.c  |   16 +++++-
 drivers/mmc/core/core.h  |    2 +
 drivers/mmc/core/mmc.c   |  143 +++++++++++++++++++++++++++++++++++++++++++---
 include/linux/mmc/card.h |    6 ++
 include/linux/mmc/host.h |    1 +
 include/linux/mmc/mmc.h  |    2 +
 7 files changed, 180 insertions(+), 9 deletions(-)

diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c
index 4409d79..f511ecc3 100644
--- a/drivers/mmc/card/block.c
+++ b/drivers/mmc/card/block.c
@@ -2010,9 +2010,26 @@ static int mmc_blk_issue_rq(struct mmc_queue *mq, struct request *req)
 	unsigned long flags;
 	unsigned int cmd_flags = req ? req->cmd_flags : 0;
 
-	if (req && !mq->mqrq_prev->req)
+	if (unlikely(req && mmc_card_mmc(card) &&
+		(card->ext_csd.power_off_notification ==
+		EXT_CSD_SLEEP_NOTIFICATION))) {
+		/* restoring the power_off_notification
+		 * field's state to as it was before so
+		 * that the sleep notification will be
+		 * able to resume later
+		 */
+		card->ext_csd.power_off_notification = EXT_CSD_POWER_ON;
+	}
+
+	if (req && !mq->mqrq_prev->req) {
 		/* claim host only for the first request */
 		mmc_get_card(card);
+		if (unlikely(req &&
+			mmc_card_doing_sleep_notify(card))) {
+			mmc_interrupt_hpi(card);
+			mmc_card_clr_sleep_notify(card);
+		}
+	}
 
 	ret = mmc_blk_part_switch(card, md);
 	if (ret) {
diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index 5bda29b..a090593 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -271,7 +271,8 @@ void mmc_start_bkops(struct mmc_card *card, bool from_exception)
 
 	BUG_ON(!card);
 
-	if (!card->ext_csd.bkops_en || mmc_card_doing_bkops(card))
+	if (!card->ext_csd.bkops_en || mmc_card_doing_bkops(card) ||
+		mmc_card_doing_sleep_notify(card))
 		return;
 
 	err = mmc_read_bkops_status(card);
@@ -2630,6 +2631,19 @@ int mmc_pm_notify(struct notifier_block *notify_block,
 			err = host->bus_ops->pre_suspend(host);
 		if (!err)
 			break;
+		if (host->card && host->bus_ops->suspend) {
+			err = mmc_sleep_notify(host->card);
+			/* We assume that HPI was sent
+			 * in case of -ETIMEDOUT error,
+			 * so suspend flow can be continued
+			 */
+			if (err && err != -ETIMEDOUT) {
+				pr_err("%s:sleep notify err=%d\n",
+					__func__, err);
+				return -EBUSY;
+			}
+			break;
+		}
 
 		/* Calling bus_ops->remove() with a claimed host can deadlock */
 		host->bus_ops->remove(host);
diff --git a/drivers/mmc/core/core.h b/drivers/mmc/core/core.h
index d76597c..b6b4431 100644
--- a/drivers/mmc/core/core.h
+++ b/drivers/mmc/core/core.h
@@ -14,6 +14,7 @@
 #include <linux/delay.h>
 
 #define MMC_CMD_RETRIES        3
+#define MMC_SLEEP_NOTIFY_MAX_TIME	0x17
 
 struct mmc_bus_ops {
 	void (*remove)(struct mmc_host *);
@@ -33,6 +34,7 @@ void mmc_attach_bus(struct mmc_host *host, const struct mmc_bus_ops *ops);
 void mmc_detach_bus(struct mmc_host *host);
 
 void mmc_init_erase(struct mmc_card *card);
+int mmc_sleep_notify(struct mmc_card *card);
 
 void mmc_set_chip_select(struct mmc_host *host, int mode);
 void mmc_set_clock(struct mmc_host *host, unsigned int hz);
diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
index 02ad792..1d97d24 100644
--- a/drivers/mmc/core/mmc.c
+++ b/drivers/mmc/core/mmc.c
@@ -57,6 +57,11 @@ static const unsigned int tacc_mant[] = {
 		__res & __mask;						\
 	})
 
+#define GET_SLEEP_NOTIFY_TIME(value) \
+	(10 * (1 << (unsigned int)(value)))
+#define GET_SLEEP_NOTIFY_TIME_MSEC(value) \
+	(DIV_ROUND_UP(GET_SLEEP_NOTIFY_TIME(value), 1000))
+
 /*
  * Given the decoded CSD structure, decode the raw CID to our CID structure.
  */
@@ -571,6 +576,8 @@ static int mmc_decode_ext_csd(struct mmc_card *card, u8 *ext_csd)
 		card->ext_csd.ffu_capable =
 			(ext_csd[EXT_CSD_SUPPORTED_MODE] & 0x1) &&
 			!(ext_csd[EXT_CSD_FW_CONFIG] & 0x1);
+		card->ext_csd.sleep_notify_time =
+			ext_csd[EXT_CSD_SLEEP_NOTIFICATION_TIME];
 	}
 out:
 	return err;
@@ -1468,6 +1475,15 @@ static int mmc_init_card(struct mmc_host *host, u32 ocr,
 			card->ext_csd.hpi_en = 1;
 	}
 
+	/* sleep notify enable/disable for eMMC 5.0 and above */
+	if ((card->ext_csd.rev >= 7) &&  card->ext_csd.hpi_en &&
+			(card->host->caps2 & MMC_CAP2_SLEEP_NOTIFY) &&
+			card->ext_csd.sleep_notify_time > 0 &&
+			card->ext_csd.sleep_notify_time <=
+				MMC_SLEEP_NOTIFY_MAX_TIME) {
+		card->can_sleep_notify = 1;
+	}
+
 	/*
 	 * If cache size is higher than 0, this indicates
 	 * the existence of cache and it can be turned on.
@@ -1576,6 +1592,33 @@ static int mmc_sleep(struct mmc_host *host)
 	return err;
 }
 
+/*
+ * check if device is in program state (busy)
+ */
+static bool mmc_device_prg_state(struct mmc_card *card)
+{
+	int rc;
+	u32 status;
+	bool state;
+
+	mmc_get_card(card);
+	rc = mmc_send_status(card, &status);
+	if (rc) {
+		pr_err("%s: Get card status fail. rc=%d\n",
+			mmc_hostname(card->host), rc);
+		state = false;
+		goto out;
+	}
+
+	if (R1_CURRENT_STATE(status) == R1_STATE_PRG)
+		state =  true;
+	else
+		state =  false;
+out:
+	mmc_put_card(card);
+	return state;
+}
+
 static int mmc_can_poweroff_notify(const struct mmc_card *card)
 {
 	return card &&
@@ -1585,22 +1628,108 @@ static int mmc_can_poweroff_notify(const struct mmc_card *card)
 
 static int mmc_poweroff_notify(struct mmc_card *card, unsigned int notify_type)
 {
-	unsigned int timeout = card->ext_csd.generic_cmd6_time;
+	unsigned int timeout_ms = card->ext_csd.generic_cmd6_time;
 	int err;
+	bool use_busy_signal;
 
 	/* Use EXT_CSD_POWER_OFF_SHORT as default notification type. */
 	if (notify_type == EXT_CSD_POWER_OFF_LONG)
-		timeout = card->ext_csd.power_off_longtime;
+		timeout_ms = card->ext_csd.power_off_longtime;
+	else if (notify_type == EXT_CSD_SLEEP_NOTIFICATION) {
+		/* calculate the maximum timeout for the
+		 * switch command when notifying the device
+		 * that it is about to move to sleep */
+		timeout_ms = GET_SLEEP_NOTIFY_TIME_MSEC(
+			card->ext_csd.sleep_notify_time);
+	}
 
+	/* do not wait on busy signal in case of
+	 * Sleep Notification - to let host get
+	 * another requests
+	 */
+	use_busy_signal = (notify_type == EXT_CSD_SLEEP_NOTIFICATION) ?
+			false : true;
 	err = __mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
 			EXT_CSD_POWER_OFF_NOTIFICATION,
-			notify_type, timeout, true, false, false);
-	if (err)
+			notify_type, timeout_ms,
+			use_busy_signal, false, false);
+	if (!err) {
+		card->ext_csd.power_off_notification = notify_type;
+	} else {
 		pr_err("%s: Power Off Notification timed out, %u\n",
-		       mmc_hostname(card->host), timeout);
+			mmc_hostname(card->host), timeout_ms);
+	}
+
+	return err;
+}
 
-	/* Disable the power off notification after the switch operation. */
-	card->ext_csd.power_off_notification = EXT_CSD_NO_POWER_NOTIFICATION;
+int mmc_sleep_notify(struct mmc_card *card)
+{
+	int err = 0;
+	bool is_busy = 0;
+	unsigned long prg_wait = 0;
+
+	if (!card->can_sleep_notify || !mmc_can_poweroff_notify(card))
+		return 0;
+
+	if (!mmc_card_doing_sleep_notify(card)) {
+		mmc_get_card(card);
+		mmc_card_set_sleep_notify(card);
+		err = mmc_poweroff_notify(card,
+			EXT_CSD_SLEEP_NOTIFICATION);
+		mmc_put_card(card);
+		if (err) {
+			pr_err("%s: mmc_poweroff_notify failed with %d\n",
+			       __func__, err);
+			goto out;
+		}
+
+		prg_wait = jiffies +
+			msecs_to_jiffies(GET_SLEEP_NOTIFY_TIME_MSEC(
+			card->ext_csd.sleep_notify_time));
+		}
+
+	/*
+	 * Loop will run until:
+	 * 1. Device is no more in Busy state
+	 * 2. Sleep notification is not interrupted by HPI & IO request
+	 */
+	do {
+		/* added some delay to avoid sending card status too often */
+		msleep(20);
+		err = 0;
+		/* Stop polling in case sleep notification was HPIed already */
+		if (!mmc_card_doing_sleep_notify(card)) {
+			is_busy = mmc_device_prg_state(card);
+			if (is_busy)
+				err = -EBUSY;
+			break;
+		}
+		is_busy = mmc_device_prg_state(card);
+		if (is_busy && time_after(jiffies, prg_wait)) {
+			/*
+			 * making sure we are still in busy before
+			 * sending HPI due to timeout error
+			 */
+			is_busy = mmc_device_prg_state(card);
+			if (is_busy) {
+				if (mmc_card_doing_sleep_notify(card)) {
+					card->ext_csd.power_off_notification =
+						EXT_CSD_POWER_ON;
+					mmc_interrupt_hpi(card);
+				}
+				err = -ETIMEDOUT;
+				break;
+			}
+		}
+	} while (is_busy);
+
+out:
+	mmc_card_clr_sleep_notify(card);
+	if (err) {
+		pr_err("%s: mmc_poweroff_notify for sleep failed with %d\n",
+		       mmc_hostname(card->host), err);
+	}
 
 	return err;
 }
diff --git a/include/linux/mmc/card.h b/include/linux/mmc/card.h
index 4d69c00..6998344 100644
--- a/include/linux/mmc/card.h
+++ b/include/linux/mmc/card.h
@@ -62,6 +62,7 @@ struct mmc_ext_csd {
 	unsigned int		sa_timeout;		/* Units: 100ns */
 	unsigned int		generic_cmd6_time;	/* Units: 10ms */
 	unsigned int            power_off_longtime;     /* Units: ms */
+	unsigned int		sleep_notify_time;	/* Units: us */
 	u8			power_off_notification;	/* state */
 	unsigned int		hs_max_dtr;
 	unsigned int		hs200_max_dtr;
@@ -262,6 +263,7 @@ struct mmc_card {
 #define MMC_CARD_REMOVED	(1<<4)		/* card has been removed */
 #define MMC_STATE_DOING_BKOPS	(1<<5)		/* card is doing BKOPS */
 #define MMC_STATE_SUSPENDED	(1<<6)		/* card is suspended */
+#define MMC_STATE_SLEEP_NOTIFY (1<<7)		/* card in sleep notify */
 	unsigned int		quirks; 	/* card quirks */
 #define MMC_QUIRK_LENIENT_FN0	(1<<0)		/* allow SDIO FN0 writes outside of the VS CCCR range */
 #define MMC_QUIRK_BLKSZ_FOR_BYTE_MODE (1<<1)	/* use func->cur_blksize */
@@ -309,6 +311,7 @@ struct mmc_card {
 	struct dentry		*debugfs_root;
 	struct mmc_part	part[MMC_NUM_PHY_PARTITION]; /* physical partitions */
 	unsigned int    nr_parts;
+	u8 can_sleep_notify;	/* sleep_notify on/off */
 };
 
 /*
@@ -427,6 +430,7 @@ static inline void __maybe_unused remove_quirk(struct mmc_card *card, int data)
 #define mmc_card_removed(c)	((c) && ((c)->state & MMC_CARD_REMOVED))
 #define mmc_card_doing_bkops(c)	((c)->state & MMC_STATE_DOING_BKOPS)
 #define mmc_card_suspended(c)	((c)->state & MMC_STATE_SUSPENDED)
+#define mmc_card_doing_sleep_notify(c) ((c)->state & MMC_STATE_SLEEP_NOTIFY)
 
 #define mmc_card_set_present(c)	((c)->state |= MMC_STATE_PRESENT)
 #define mmc_card_set_readonly(c) ((c)->state |= MMC_STATE_READONLY)
@@ -437,6 +441,8 @@ static inline void __maybe_unused remove_quirk(struct mmc_card *card, int data)
 #define mmc_card_clr_doing_bkops(c)	((c)->state &= ~MMC_STATE_DOING_BKOPS)
 #define mmc_card_set_suspended(c) ((c)->state |= MMC_STATE_SUSPENDED)
 #define mmc_card_clr_suspended(c) ((c)->state &= ~MMC_STATE_SUSPENDED)
+#define mmc_card_set_sleep_notify(c)	((c)->state |= MMC_STATE_SLEEP_NOTIFY)
+#define mmc_card_clr_sleep_notify(c)	((c)->state &= ~MMC_STATE_SLEEP_NOTIFY)
 
 /*
  * Quirk add/remove for MMC products.
diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
index 9f32270..4c0542a 100644
--- a/include/linux/mmc/host.h
+++ b/include/linux/mmc/host.h
@@ -291,6 +291,7 @@ struct mmc_host {
 				 MMC_CAP2_HS400_1_2V)
 #define MMC_CAP2_HSX00_1_2V	(MMC_CAP2_HS200_1_2V_SDR | MMC_CAP2_HS400_1_2V)
 #define MMC_CAP2_SDIO_IRQ_NOTHREAD (1 << 17)
+#define MMC_CAP2_SLEEP_NOTIFY	(1 << 18)	/* sleep notify supported */
 
 	mmc_pm_flag_t		pm_caps;	/* supported pm features */
 
diff --git a/include/linux/mmc/mmc.h b/include/linux/mmc/mmc.h
index 49ad7a9..69bda9a 100644
--- a/include/linux/mmc/mmc.h
+++ b/include/linux/mmc/mmc.h
@@ -314,6 +314,7 @@ struct _mmc_csd {
 #define EXT_CSD_PWR_CL_52_360		202	/* RO */
 #define EXT_CSD_PWR_CL_26_360		203	/* RO */
 #define EXT_CSD_SEC_CNT			212	/* RO, 4 bytes */
+#define EXT_CSD_SLEEP_NOTIFICATION_TIME	216	/* RO */
 #define EXT_CSD_S_A_TIMEOUT		217	/* RO */
 #define EXT_CSD_REL_WR_SEC_C		222	/* RO */
 #define EXT_CSD_HC_WP_GRP_SIZE		221	/* RO */
@@ -408,6 +409,7 @@ struct _mmc_csd {
 #define EXT_CSD_POWER_ON		1
 #define EXT_CSD_POWER_OFF_SHORT		2
 #define EXT_CSD_POWER_OFF_LONG		3
+#define EXT_CSD_SLEEP_NOTIFICATION	4
 
 #define EXT_CSD_PWR_CL_8BIT_MASK	0xF0	/* 8 bit PWR CLS */
 #define EXT_CSD_PWR_CL_4BIT_MASK	0x0F	/* 8 bit PWR CLS */
-- 
1.7.9.5