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mmc: mmc: Relax checking for switch errors after HS200 switch

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The JEDEC specification indicates CMD13 can be used after a HS200 switch
to check for errors. However in practice some boards experience CRC errors
in the CMD13 response. Consequently, for HS200, CRC errors are not a
reliable way to know the switch failed. If there really is a problem, we
would expect tuning will fail and the result ends up the same. So change
the error condition to ignore CRC errors in that case.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Acked-by: Jaehoon Chung <jh80.chung@samsung.com>
Reviewed-by: Shawn Lin <shawn.lin@rock-chips.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
This commit is contained in:
Adrian Hunter 2016-12-02 13:16:35 +02:00 committed by Ulf Hansson
parent db52d4f8a4
commit ef3d232245
3 changed files with 22 additions and 3 deletions
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15
drivers/mmc/core/mmc.c
View File

@ -1240,7 +1240,12 @@ int mmc_hs400_to_hs200(struct mmc_card *card)
mmc_set_timing(host, MMC_TIMING_MMC_HS200);
err = mmc_switch_status(card);
/*
* For HS200, CRC errors are not a reliable way to know the switch
* failed. If there really is a problem, we would expect tuning will
* fail and the result ends up the same.
*/
err = __mmc_switch_status(card, false);
if (err)
goto out_err;
@ -1403,7 +1408,13 @@ static int mmc_select_hs200(struct mmc_card *card)
old_timing = host->ios.timing;
mmc_set_timing(host, MMC_TIMING_MMC_HS200);
err = mmc_switch_status(card);
/*
* For HS200, CRC errors are not a reliable way to know the
* switch failed. If there really is a problem, we would expect
* tuning will fail and the result ends up the same.
*/
err = __mmc_switch_status(card, false);
/*
* mmc_select_timing() assumes timing has not changed if
* it is a switch error.

9
drivers/mmc/core/mmc_ops.c
View File

@ -431,18 +431,25 @@ static int mmc_switch_status_error(struct mmc_host *host, u32 status)
}
/* Caller must hold re-tuning */
int mmc_switch_status(struct mmc_card *card)
int __mmc_switch_status(struct mmc_card *card, bool crc_err_fatal)
{
u32 status;
int err;
err = mmc_send_status(card, &status);
if (!crc_err_fatal && err == -EILSEQ)
return 0;
if (err)
return err;
return mmc_switch_status_error(card->host, status);
}
int mmc_switch_status(struct mmc_card *card)
{
return __mmc_switch_status(card, true);
}
static int mmc_poll_for_busy(struct mmc_card *card, unsigned int timeout_ms,
bool send_status, bool retry_crc_err)
{

1
drivers/mmc/core/mmc_ops.h
View File

@ -28,6 +28,7 @@ int mmc_bus_test(struct mmc_card *card, u8 bus_width);
int mmc_send_hpi_cmd(struct mmc_card *card, u32 *status);
int mmc_can_ext_csd(struct mmc_card *card);
int mmc_switch_status(struct mmc_card *card);
int __mmc_switch_status(struct mmc_card *card, bool crc_err_fatal);
int __mmc_switch(struct mmc_card *card, u8 set, u8 index, u8 value,
unsigned int timeout_ms, unsigned char timing,
bool use_busy_signal, bool send_status, bool retry_crc_err);