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mmc: core: enable CMD19 tuning for DDR50 mode

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As SD Specifications Part1 Physical Layer Specification Version
3.01 says, CMD19 tuning is available for unlocked cards in transfer
state of 1.8V signaling mode. The small difference between v3.00
and 3.01 spec means that CMD19 tuning is also available for DDR50
mode.

Signed-off-by: Weijun Yang <york.yang@csr.com>
Signed-off-by: Barry Song <Baohua.Song@csr.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
This commit is contained in:
Weijun Yang 2015-10-04 12:04:11 +00:00 committed by Ulf Hansson
parent b093410c9a
commit 4324f6de6d
1 changed files with 18 additions and 2 deletions
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20
drivers/mmc/core/sd.c
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@ -626,9 +626,25 @@ static int mmc_sd_init_uhs_card(struct mmc_card *card)
* SDR104 mode SD-cards. Note that tuning is mandatory for SDR104.
*/
if (!mmc_host_is_spi(card->host) &&
(card->sd_bus_speed == UHS_SDR50_BUS_SPEED ||
card->sd_bus_speed == UHS_SDR104_BUS_SPEED))
(card->sd_bus_speed == UHS_SDR50_BUS_SPEED ||
card->sd_bus_speed == UHS_DDR50_BUS_SPEED ||
card->sd_bus_speed == UHS_SDR104_BUS_SPEED)) {
err = mmc_execute_tuning(card);
/*
* As SD Specifications Part1 Physical Layer Specification
* Version 3.01 says, CMD19 tuning is available for unlocked
* cards in transfer state of 1.8V signaling mode. The small
* difference between v3.00 and 3.01 spec means that CMD19
* tuning is also available for DDR50 mode.
*/
if (err && card->sd_bus_speed == UHS_DDR50_BUS_SPEED) {
pr_warn("%s: ddr50 tuning failed\n",
mmc_hostname(card->host));
err = 0;
}
}
out:
kfree(status);