Commit 83b600b8 authored by Adrian Hunter's avatar Adrian Hunter Committed by Ulf Hansson
Browse files

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: default avatarAdrian Hunter <adrian.hunter@intel.com>
Signed-off-by: default avatarYangbo Lu <yangbo.lu@nxp.com>
Signed-off-by: default avatarUlf Hansson <ulf.hansson@linaro.org>
parent ba49cbd0

drivers/mmc/host/sdhci.c

+8 −3
Original line number Diff line number Diff line
@@ -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;

}

drivers/mmc/host/sdhci.h

+2 −0
Original line number Diff line number Diff line
@@ -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;

};

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