linux/drivers/mmc
Ulf Hansson e173f8911f mmc: core: Update CMD13 polling policy when switch to HS DDR mode
According to the JEDEC specification, during bus timing change operations
for mmc, sending a CMD13 could trigger CRC errors.

As switching to HS DDR mode indeed causes a bus timing change, polling with
CMD13 to detect card busy, may thus potentially trigger CRC errors.
Currently these errors are treated as the switch to HS DDR mode failed.

To improve this behaviour, let's instead tell __mmc_switch() to retry when
it encounters CRC errors during polling.

Moreover, when switching to HS DDR mode, let's make sure the CMD13 polling
is done by having the mmc host and the mmc card, being configured to
operate at the same selected bus speed timing. Fix this by providing
MMC_TIMING_MMC_DDR52 as the timing parameter to __mmc_switch().

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Tested-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
2016-11-29 09:05:26 +01:00
..
card mmc: block: move packed command struct init 2016-11-29 09:05:04 +01:00
core mmc: core: Update CMD13 polling policy when switch to HS DDR mode 2016-11-29 09:05:26 +01:00
host mmc: sdhci-pci: Allow deferred probe for sd card detect gpio 2016-11-29 09:05:21 +01:00
Kconfig
Makefile mmc: sdhci-pci: add platform data 2012-01-11 23:58:47 -05:00