From 5b793522904e315c7bd3c4c9db96b1ab98cd9714 Mon Sep 17 00:00:00 2001 From: Ulf Hansson Date: Mon, 7 Apr 2025 17:27:54 +0200 Subject: [PATCH] mmc: core: Add support for graceful host removal for eMMC An mmc host driver may allow to unbind from its corresponding host device. If an eMMC card is attached to the host, the mmc core will just try to cut the power for it, without obeying to the eMMC spec. Potentially this may damage the card and it may also prevent us from successfully doing a re-initialization of it, which would typically happen if/when we try to re-bind the mmc host driver. To fix these problems, let's implement a graceful power-down of the card at host removal. Reported-by: Wolfram Sang Reviewed-by: Wolfram Sang Tested-by: Wolfram Sang Signed-off-by: Ulf Hansson Link: https://lore.kernel.org/r/20250407152759.25160-5-ulf.hansson@linaro.org --- drivers/mmc/core/mmc.c | 27 +++++++++++++++++---------- 1 file changed, 17 insertions(+), 10 deletions(-) diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c index c41cee7ef2677..48656dadf93b8 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_UNBIND, }; static const unsigned int tran_exp[] = { @@ -2054,15 +2055,6 @@ static int mmc_poweroff_notify(struct mmc_card *card, unsigned int notify_type) return err; } -/* - * Host is being removed. Free up the current card. - */ -static void mmc_remove(struct mmc_host *host) -{ - mmc_remove_card(host->card); - host->card = NULL; -} - /* * Card detection - card is alive. */ @@ -2088,7 +2080,8 @@ static void mmc_detect(struct mmc_host *host) mmc_put_card(host->card, NULL); if (err) { - mmc_remove(host); + mmc_remove_card(host->card); + host->card = NULL; mmc_claim_host(host); mmc_detach_bus(host); @@ -2160,6 +2153,20 @@ out: return err; } +/* + * Host is being removed. Free up the current card and do a graceful power-off. + */ +static void mmc_remove(struct mmc_host *host) +{ + get_device(&host->card->dev); + mmc_remove_card(host->card); + + _mmc_suspend(host, MMC_POWEROFF_UNBIND); + + put_device(&host->card->dev); + host->card = NULL; +} + /* * Suspend callback */ -- 2.47.3