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Commit 0760c355 authored by Adrian Hunter's avatar Adrian Hunter Committed by Ulf Hansson
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mmc: sdhci: Always allow tuning to fall back to fixed sampling 



SDHCI falls back to fixed sampling if there is an error during tuning.
However it also reports an error unless there is periodic re-tuning.
That is not the best option because:
a) there is a reasonable chance that fixed sampling will work, especially
at room temperature.
b) re-tuning will be done again anyway if there are CRC errors.
Change to return no error always when falling back to fixed sampling.

Signed-off-by: default avatarAdrian Hunter <adrian.hunter@intel.com>
Signed-off-by: default avatarUlf Hansson <ulf.hansson@linaro.org>
parent 5ef5203b

drivers/mmc/host/sdhci.c

+2 −18
Original line number Diff line number Diff line
@@ -2098,8 +2098,6 @@ static int sdhci_execute_tuning(struct mmc_host *mmc, u32 opcode) 
			sdhci_do_reset(host, SDHCI_RESET_CMD);

			sdhci_do_reset(host, SDHCI_RESET_DATA);



			err = -EIO;



			if (cmd.opcode != MMC_SEND_TUNING_BLOCK_HS200)

				goto out;
@@ -2137,24 +2135,10 @@ static int sdhci_execute_tuning(struct mmc_host *mmc, u32 opcode) 
		ctrl &= ~SDHCI_CTRL_EXEC_TUNING;

		sdhci_writew(host, ctrl, SDHCI_HOST_CONTROL2);

	}

	if (!(ctrl & SDHCI_CTRL_TUNED_CLK)) {

	if (!(ctrl & SDHCI_CTRL_TUNED_CLK))

		pr_info(DRIVER_NAME ": Tuning procedure failed, falling back to fixed sampling clock\n");

		err = -EIO;

	}



out:

	if (tuning_count) {

		/*

		 * In case tuning fails, host controllers which support

		 * re-tuning can try tuning again at a later time, when the

		 * re-tuning timer expires.  So for these controllers, we

		 * return 0. Since there might be other controllers who do not

		 * have this capability, we return error for them.

		 */

		err = 0;

	}



	host->mmc->retune_period = err ? 0 : tuning_count;

	host->mmc->retune_period = tuning_count;



	sdhci_writel(host, host->ier, SDHCI_INT_ENABLE);

	sdhci_writel(host, host->ier, SDHCI_SIGNAL_ENABLE);