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mmc: sdhci: Control the delay between tuning commands 

The delay between tuning commands for SD cards is not part of the
specification. A driver that needs it probably needs it for eMMC
too, whereas most drivers would probably like to set it to 0. Make
it a host member (host->tuning_delay) that defaults to the existing
behaviour. Drivers can set it to zero to eliminate the delay, or
set it to a positive value to always have a delay.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Yangbo Lu <yangbo.lu@nxp.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
This commit is contained in:
Adrian Hunter 2017-04-20 16:14:43 +08:00 committed by Ulf Hansson
parent ba49cbd093
commit 83b600b8de
2 changed files with 10 additions and 3 deletions
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11
drivers/mmc/host/sdhci.c
View File

@ -2108,9 +2108,9 @@ static void __sdhci_execute_tuning(struct sdhci_host *host, u32 opcode)
break;
}
/* eMMC spec does not require a delay between tuning cycles */
if (opcode == MMC_SEND_TUNING_BLOCK)
mdelay(1);
/* Spec does not require a delay between tuning cycles */
if (host->tuning_delay > 0)
mdelay(host->tuning_delay);
}
pr_info("%s: Tuning failed, falling back to fixed sampling clock\n",
@ -2172,6 +2172,9 @@ int sdhci_execute_tuning(struct mmc_host *mmc, u32 opcode)
host->mmc->retune_period = tuning_count;
if (host->tuning_delay < 0)
host->tuning_delay = opcode == MMC_SEND_TUNING_BLOCK;
sdhci_start_tuning(host);
__sdhci_execute_tuning(host, opcode);
@ -3114,6 +3117,8 @@ struct sdhci_host *sdhci_alloc_host(struct device *dev,
host->cqe_ier = SDHCI_CQE_INT_MASK;
host->cqe_err_ier = SDHCI_CQE_INT_ERR_MASK;
host->tuning_delay = -1;
return host;
}

2
drivers/mmc/host/sdhci.h
View File

@ -538,6 +538,8 @@ struct sdhci_host {
#define SDHCI_TUNING_MODE_1 0
#define SDHCI_TUNING_MODE_2 1
#define SDHCI_TUNING_MODE_3 2
/* Delay (ms) between tuning commands */
int tuning_delay;
unsigned long private[0] ____cacheline_aligned;
};