From 6892550c4aea4e9fcbee3cdb6947ac78085981ae Mon Sep 17 00:00:00 2001 From: Marek Vasut Date: Wed, 6 Feb 2019 11:34:27 +0100 Subject: [PATCH] mmc: Do not poll using CMD13 when changing timing When using CMD6 to switch eMMC card timing from HS200/HS400 to HS/legacy, do not poll for the completion status using CMD13, but rather wait 50mS. Once the card receives the CMD6 and starts executing it, the bus is in undefined state until both the card finishes executing the command and until the controller switches the bus to matching timing configuration. During this time, it is not possible to transport any commands or data across the bus, which includes the CMD13. Signed-off-by: Marek Vasut Cc: Jaehoon Chung --- drivers/mmc/mmc.c | 28 ++++++++++++++++++++-------- 1 file changed, 20 insertions(+), 8 deletions(-) diff --git a/drivers/mmc/mmc.c b/drivers/mmc/mmc.c index 84d157ff40..b04345a1e1 100644 --- a/drivers/mmc/mmc.c +++ b/drivers/mmc/mmc.c @@ -724,7 +724,8 @@ static int mmc_send_ext_csd(struct mmc *mmc, u8 *ext_csd) return err; } -int mmc_switch(struct mmc *mmc, u8 set, u8 index, u8 value) +static int __mmc_switch(struct mmc *mmc, u8 set, u8 index, u8 value, + bool send_status) { struct mmc_cmd cmd; int timeout = 1000; @@ -740,19 +741,29 @@ int mmc_switch(struct mmc *mmc, u8 set, u8 index, u8 value) while (retries > 0) { ret = mmc_send_cmd(mmc, &cmd, NULL); - /* Waiting for the ready status */ - if (!ret) { - ret = mmc_send_status(mmc, timeout); - return ret; + if (ret) { + retries--; + continue; + } + + if (!send_status) { + mdelay(50); + return 0; } - retries--; + /* Waiting for the ready status */ + return mmc_send_status(mmc, timeout); } return ret; } +int mmc_switch(struct mmc *mmc, u8 set, u8 index, u8 value) +{ + return __mmc_switch(mmc, set, index, value, true); +} + #if !CONFIG_IS_ENABLED(MMC_TINY) static int mmc_set_card_speed(struct mmc *mmc, enum bus_mode mode, bool hsdowngrade) @@ -784,8 +795,9 @@ static int mmc_set_card_speed(struct mmc *mmc, enum bus_mode mode, default: return -EINVAL; } - err = mmc_switch(mmc, EXT_CSD_CMD_SET_NORMAL, EXT_CSD_HS_TIMING, - speed_bits); + + err = __mmc_switch(mmc, EXT_CSD_CMD_SET_NORMAL, EXT_CSD_HS_TIMING, + speed_bits, !hsdowngrade); if (err) return err; -- 2.39.5