diff mbox series

[v5,2/4] mmc: core: Add MMC_POWEROFF_UNDERVOLTAGE support in _mmc_suspend()

Message ID 20250506095118.2239459-3-o.rempel@pengutronix.de
State New
Headers show
Series mmc: handle undervoltage events and prevent eMMC corruption | expand

Commit Message

Oleksij Rempel May 6, 2025, 9:51 a.m. UTC 
Introduce MMC_POWEROFF_UNDERVOLTAGE as a new mmc_poweroff_type value and
adjust _mmc_suspend() to skip cache flush for this case. This prepares for
undervoltage handling in a follow-up patch.

Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
---
changes v5:
- rebase against latest mmc/next
- use MMC_POWEROFF_UNDERVOLTAGE enum instead of function parameter.
changes v3:
- add comments
- make sure _mmc_flush_cache is not executed in the undervoltage case
---
 drivers/mmc/core/mmc.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)
diff mbox series

Patch

diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
index 5be9b42d5057..b67de2b62830 100644
--- a/drivers/mmc/core/mmc.c
+++ b/drivers/mmc/core/mmc.c
@@ -36,6 +36,7 @@ 
 enum mmc_poweroff_type {
 	MMC_POWEROFF_SUSPEND,
 	MMC_POWEROFF_SHUTDOWN,
+	MMC_POWEROFF_UNDERVOLTAGE,
 	MMC_POWEROFF_UNBIND,
 };
 
@@ -2132,9 +2133,15 @@  static int _mmc_suspend(struct mmc_host *host, enum mmc_poweroff_type pm_type)
 	if (mmc_card_suspended(host->card))
 		goto out;
 
-	err = _mmc_flush_cache(host);
-	if (err)
-		goto out;
+	/*
+	 * For the undervoltage case, we care more about device integrity.
+	 * Avoid cache flush and notify the device to power off quickly.
+	 */
+	if (pm_type != MMC_POWEROFF_UNDERVOLTAGE) {
+		err = _mmc_flush_cache(host);
+		if (err)
+			goto out;
+	}
 
 	if (mmc_card_can_poweroff_notify(host->card) &&
 	    mmc_host_can_poweroff_notify(host, pm_type))