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, 21 insertions, 2 deletions

diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
index 4e869d371a03..f8ea9387d75c 100644
--- a/drivers/mmc/core/mmc.c
+++ b/drivers/mmc/core/mmc.c
@@ -458,10 +458,12 @@ static int mmc_read_ext_csd(struct mmc_card *card, u8 *ext_csd)
         else
                 card->erased_byte = 0x0;
 
-        if (card->ext_csd.rev >= 6)
+        if (card->ext_csd.rev >= 6) {
                 card->ext_csd.generic_cmd6_time = 10 *
                         ext_csd[EXT_CSD_GENERIC_CMD6_TIME];
-        else
+                card->ext_csd.power_off_longtime = 10 *
+                        ext_csd[EXT_CSD_POWER_OFF_LONG_TIME];
+        } else
                 card->ext_csd.generic_cmd6_time = 0;
 
 out:
@@ -846,6 +848,23 @@ 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_CAP2_POWEROFF_NOTIFY) &&
+            (card->poweroff_notify_state == MMC_NO_POWER_NOTIFICATION)) {
+                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)
+                card->poweroff_notify_state = MMC_POWERED_ON;
+
+        /*
          * Activate high speed (if supported)
          */
         if ((card->ext_csd.hs_max_dtr != 0) &&