linux/drivers/mmc
Alek Du b704441e38 mmc: sdhci: fix the timeout check window for clock and reset
We observed some premature timeouts on a virtualization platform, the log
is like this:

case 1:
[159525.255629] mmc1: Internal clock never stabilised.
[159525.255818] mmc1: sdhci: ============ SDHCI REGISTER DUMP ===========
[159525.256049] mmc1: sdhci: Sys addr:  0x00000000 | Version:  0x00001002
...
[159525.257205] mmc1: sdhci: Wake-up:   0x00000000 | Clock:    0x0000fa03
From the clock control register dump, we are pretty sure the clock was
stablized.

case 2:
[  914.550127] mmc1: Reset 0x2 never completed.
[  914.550321] mmc1: sdhci: ============ SDHCI REGISTER DUMP ===========
[  914.550608] mmc1: sdhci: Sys addr:  0x00000010 | Version:  0x00001002

After checking the sdhci code, we found the timeout check actually has a
little window that the CPU can be scheduled out and when it comes back,
the original time set or check is not valid.

Fixes: 5a436cc0af ("mmc: sdhci: Optimize delay loops")
Cc: stable@vger.kernel.org      # v4.12+
Signed-off-by: Alek Du <alek.du@intel.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
2018-12-06 11:22:00 +01:00
..
core mmc: core: use mrq->sbc when sending CMD23 for RPMB 2018-12-04 10:12:12 +01:00
host mmc: sdhci: fix the timeout check window for clock and reset 2018-12-06 11:22:00 +01:00
Kconfig mmc: core: Remove option not to use blk-mq 2017-12-11 12:55:02 +01:00
Makefile mmc: Kconfig: downgrade CONFIG_MMC_DEBUG for host drivers only 2017-08-30 14:01:34 +02:00