From 3b6c472822f8bdeaa3cea8290f5b4a210dca5585 Mon Sep 17 00:00:00 2001 From: Ulf Hansson Date: Thu, 3 Mar 2022 17:45:22 +0100 Subject: [PATCH] mmc: core: Improve fallback to speed modes if eMMC HS200 fails In the error path of mmc_select_hs200() we are trying our best to restore the card/host into a valid state. This makes sense, especially if we encounter a simple switch error (-EBADMSG). However, rather than then continue with using the legacy speed mode, let's try the other better speed modes first. Additionally, let's update the card->mmc_avail_type to avoid us from trying a broken HS200 mode again. In an Amlogic S905W based TV box where the switch to HS200 mode fails for the eMMC, this allows us to use the eMMC in DDR mode in favor of the legacy mode, which greatly improves the performance. Suggested-by: Heiner Kallweit Signed-off-by: Ulf Hansson Tested-by: Heiner Kallweit Link: https://lore.kernel.org/r/20220303164522.129583-1-ulf.hansson@linaro.org --- drivers/mmc/core/mmc.c | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-) diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c index 43d1b9b2fa49..3f5d0d7c021c 100644 --- a/drivers/mmc/core/mmc.c +++ b/drivers/mmc/core/mmc.c @@ -1523,13 +1523,23 @@ static int mmc_select_timing(struct mmc_card *card) if (!mmc_can_ext_csd(card)) goto bus_speed; - if (card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS400ES) + if (card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS400ES) { err = mmc_select_hs400es(card); - else if (card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS200) + goto out; + } + + if (card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS200) { err = mmc_select_hs200(card); - else if (card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS) + if (err == -EBADMSG) + card->mmc_avail_type &= ~EXT_CSD_CARD_TYPE_HS200; + else + goto out; + } + + if (card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS) err = mmc_select_hs(card); +out: if (err && err != -EBADMSG) return err;