linux_dsm_epyc7002/drivers/mmc
Loic Poulain a89e7bcb18 mmc: sdhci-msm: Disable CDR function on TX
The Clock Data Recovery (CDR) circuit allows to automatically adjust
the RX sampling-point/phase for high frequency cards (SDR104, HS200...).
CDR is automatically enabled during DLL configuration.
However, according to the APQ8016 reference manual, this function
must be disabled during TX and tuning phase in order to prevent any
interferences during tuning challenges and unexpected phase alteration
during TX transfers.

This patch enables/disables CDR according to the current transfer mode.

This fixes sporadic write transfer issues observed with some SDR104 and
HS200 cards.

Inspired by sdhci-msm downstream patch:
https://chromium-review.googlesource.com/c/chromiumos/third_party/kernel/+/432516/

Reported-by: Leonid Segal <leonid.s@variscite.com>
Reported-by: Manabu Igusa <migusa@arrowjapan.com>
Signed-off-by: Loic Poulain <loic.poulain@linaro.org>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Acked-by: Georgi Djakov <georgi.djakov@linaro.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
2018-12-17 08:26:24 +01:00
..
core mmc: convert to DEFINE_SHOW_ATTRIBUTE 2018-12-17 08:26:24 +01:00
host mmc: sdhci-msm: Disable CDR function on TX 2018-12-17 08:26:24 +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