[PATCH 5.2 94/94] Revert "mmc: core: do not retry CMD6 in __mmc_switch()"

From: Greg Kroah-Hartman
Date: Sun Sep 08 2019 - 08:53:16 EST

From: Jan Kaisrlik <ja.kaisrlik@xxxxxxxxx>

commit 8ad8e02c2fa70cfddc1ded53ba9001c9d444075d upstream.

Turns out the commit 3a0681c7448b ("mmc: core: do not retry CMD6 in
__mmc_switch()") breaks initialization of a Toshiba THGBMNG5 eMMC card,
when using the meson-gx-mmc.c driver on a custom board based on Amlogic

The CMD6 that switches the card into HS200 mode is then one that fails and
according to the below printed messages from the log:

[ 1.648951] mmc0: mmc_select_hs200 failed, error -84
[ 1.648988] mmc0: error -84 whilst initialising MMC card

After some analyze, it turns out that adding a delay of ~5ms inside
mmc_select_bus_width() but after mmc_compare_ext_csds() has been executed,
also fixes the problem. Adding yet some more debug code, trying to figure
out if potentially the card could be in a busy state, both by using CMD13
and ->card_busy() ops concluded that this was not the case.

Therefore, let's simply revert the commit that dropped support for retrying
of CMD6, as this also fixes the problem.

Fixes: 3a0681c7448b ("mmc: core: do not retry CMD6 in __mmc_switch()")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Jan Kaisrlik <ja.kaisrlik@xxxxxxxxx>
Signed-off-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

drivers/mmc/core/mmc_ops.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/mmc/core/mmc_ops.c
+++ b/drivers/mmc/core/mmc_ops.c
@@ -564,7 +564,7 @@ int __mmc_switch(struct mmc_card *card,
cmd.sanitize_busy = true;

- err = mmc_wait_for_cmd(host, &cmd, 0);
+ err = mmc_wait_for_cmd(host, &cmd, MMC_CMD_RETRIES);
if (err)
goto out;