mmc: core: Add Power Off Notify Feature eMMC 4.5

This patch adds support for the power off notify feature, available in
eMMC 4.5 devices. If the host has support for this feature, then the
mmc core will notify the device by setting the POWER_OFF_NOTIFICATION
byte in the extended csd register with a value of 1 (POWER_ON).

For suspend mode short timeout is used, whereas for the normal poweroff
long timeout is used.

Signed-off-by: Girish K S <girish.shivananjappa@linaro.org>
Signed-off-by: Jaehoon Chung <jh80.chung@samsung.com>
Signed-off-by: Chris Ball <cjb@laptop.org>

1 files changed, 34 insertions, 0 deletions

diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index 61d7730bc8b2..a3c4e0fe9434 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -1212,11 +1212,43 @@ 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;
+
 	mmc_host_clk_hold(host);
 
+	card = host->card;
 	host->ios.clock = 0;
 	host->ios.vdd = 0;
 
+	if (card && mmc_card_mmc(card) &&
+	    (card->poweroff_notify_state == MMC_POWERED_ON)) {
+
+		if (host->power_notify_type == MMC_HOST_PW_NOTIFY_SHORT) {
+			notify_type = EXT_CSD_POWER_OFF_SHORT;
+			timeout = card->ext_csd.generic_cmd6_time;
+			card->poweroff_notify_state = MMC_POWEROFF_SHORT;
+		} else {
+			notify_type = EXT_CSD_POWER_OFF_LONG;
+			timeout = card->ext_csd.power_off_longtime;
+			card->poweroff_notify_state = MMC_POWEROFF_LONG;
+		}
+
+		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 */
+		card->poweroff_notify_state = MMC_NO_POWER_NOTIFICATION;
+	}
+
 	/*
 	 * Reset ocr mask to be the highest possible voltage supported for
 	 * this mmc host. This value will be used at next power up.
@@ -2208,6 +2240,7 @@ 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);
 
@@ -2231,6 +2264,7 @@ 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);