mmc: core: Further avoid re-storing power to the eMMC before a shutdown

To manage a graceful power-off of the eMMC card during platform shutdown,
the prioritized option is to use the poweroff-notification command, if the
eMMC card supports it.

During a suspend request we may decide to fall back to use the sleep
command, instead of the poweroff-notification, unless the mmc host supports
a complete power-cycle of the eMMC. For this reason, we may need to restore
power and re-initialize the card, if it remains suspended when a shutdown
request is received.

However, the current condition to restore power and re-initialize the card
doesn't take into account MMC_CAP2_FULL_PWR_CYCLE_IN_SUSPEND properly. This
may lead to doing a re-initialization when it really isn't needed, as the
eMMC may already have been powered-off using the poweroff-notification
command. Let's fix the condition to avoid this.

Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Link: https://lore.kernel.org/r/20250407152759.25160-3-ulf.hansson@linaro.org

diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
index 3424bc9e20c533da1fad1e120aa6d7ab03b642fa..ee65c5b85f95c10a975dd5845e469ebc0fb9aeec 100644 (file)
--- a/drivers/mmc/core/mmc.c
+++ b/drivers/mmc/core/mmc.c
@@ -2014,6 +2014,18 @@ static bool mmc_can_poweroff_notify(const struct mmc_card *card)
                (card->ext_csd.power_off_notification == EXT_CSD_POWER_ON);
 }
 
+static bool mmc_host_can_poweroff_notify(const struct mmc_host *host,
+                                        bool is_suspend)
+{
+       if (host->caps2 & MMC_CAP2_FULL_PWR_CYCLE)
+               return true;
+
+       if (host->caps2 & MMC_CAP2_FULL_PWR_CYCLE_IN_SUSPEND && is_suspend)
+               return true;
+
+       return !is_suspend;
+}
+
 static int mmc_poweroff_notify(struct mmc_card *card, unsigned int notify_type)
 {
        unsigned int timeout = card->ext_csd.generic_cmd6_time;
@@ -2124,8 +2136,7 @@ static int _mmc_suspend(struct mmc_host *host, bool is_suspend)
                goto out;
 
        if (mmc_can_poweroff_notify(host->card) &&
-           ((host->caps2 & MMC_CAP2_FULL_PWR_CYCLE) || !is_suspend ||
-            (host->caps2 & MMC_CAP2_FULL_PWR_CYCLE_IN_SUSPEND)))
+           mmc_host_can_poweroff_notify(host, is_suspend))
                err = mmc_poweroff_notify(host->card, notify_type);
        else if (mmc_can_sleep(host->card))
                err = mmc_sleep(host);
@@ -2187,11 +2198,12 @@ static int mmc_shutdown(struct mmc_host *host)
        int err = 0;
 
        /*
-        * In a specific case for poweroff notify, we need to resume the card
-        * before we can shutdown it properly.
+        * If the card remains suspended at this point and it was done by using
+        * the sleep-cmd (CMD5), we may need to re-initialize it first, to allow
+        * us to send the preferred poweroff-notification cmd at shutdown.
         */
        if (mmc_can_poweroff_notify(host->card) &&
-               !(host->caps2 & MMC_CAP2_FULL_PWR_CYCLE))
+           !mmc_host_can_poweroff_notify(host, true))
                err = _mmc_resume(host);
 
        if (!err)