mmc: sdhci: Fix recovery from tuning timeout
authorAdrian Hunter <adrian.hunter@intel.com>
Fri, 2 Dec 2016 13:14:20 +0000 (15:14 +0200)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Mon, 9 Jan 2017 07:07:43 +0000 (08:07 +0100)
commit842ec27cd3f2d9d1f4a8c5900f2e41be864e9d49
tree7ef70965396436b49b6cab00662116cdd6dd461f
parentdae7cb41483423e2a64b128d73718b8ae5e96d2c
mmc: sdhci: Fix recovery from tuning timeout

commit 61e53bd0047d58caee0c7170613045bf96de4458 upstream.

Clearing the tuning bits should reset the tuning circuit. However there is
more to do. Reset the command and data lines for good measure, and then
for eMMC ensure the card is not still trying to process a tuning command by
sending a stop command.

Note the JEDEC eMMC specification says the stop command (CMD12) can be used
to stop a tuning command (CMD21) whereas the SD specification is silent on
the subject with respect to the SD tuning command (CMD19). Considering that
CMD12 is not a valid SDIO command, the stop command is sent only when the
tuning command is CMD21 i.e. for eMMC. That addresses cases seen so far
which have been on eMMC.

Note that this replaces the commit fe5fb2e3b58f ("mmc: sdhci: Reset cmd and
data circuits after tuning failure") which is being reverted for v4.9+.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Tested-by: Dan O'Donovan <dan@emutex.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/mmc/host/sdhci.c