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Commit ea7ba3ab authored by Gwendal Grignou's avatar Gwendal Grignou Committed by Vijay Viswanath
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mmc: core: Do regular power cycle when lacking eMMC HW reset support 



The eMMC HW reset may be implemented either via the host ops ->hw_reset()
callback or through DT and the eMMC pwrseq. Additionally some eMMC cards
don't support HW reset.

To allow a reset to be done for the different combinations of mmc hosts
and eMMC/MMC cards, let's implement a fallback via trying a regular power
cycle. This improves the mmc block layer retry mechanism of failing I/O
requests.

Change-Id: I5cafd54327cde22ea9599543382f1b294272a42c
Signed-off-by: default avatarGwendal Grignou <gwendal@chromium.org>
[Ulf: Rewrote changelog]
Signed-off-by: default avatarUlf Hansson <ulf.hansson@linaro.org>
Git-commit: 4e6c71788d6bb0e5438fc9211fa6e52dcca01474
Git-repo: git://git.linaro.org/people/ulf.hansson/mmc.git


[vviswana@codeaurora.org: resolve trivial merge conflicts]
Signed-off-by: default avatarVijay Viswanath <vviswana@codeaurora.org>
parent 8d601310

drivers/mmc/core/core.c

+3 −2
Original line number Diff line number Diff line
@@ -3969,8 +3969,9 @@ int mmc_hw_reset(struct mmc_host *host) 
	ret = host->bus_ops->reset(host);

	mmc_bus_put(host);



	if (ret != -EOPNOTSUPP)

		pr_warn("%s: tried to reset card\n", mmc_hostname(host));

	if (ret)

		pr_warn("%s: tried to reset card, got error %d\n",

			mmc_hostname(host), ret);



	return ret;

}

drivers/mmc/core/mmc.c

+11 −15
Original line number Diff line number Diff line
@@ -2893,21 +2893,17 @@ static int mmc_reset(struct mmc_host *host) 
{

	struct mmc_card *card = host->card;



	if (!(host->caps & MMC_CAP_HW_RESET) || !host->ops->hw_reset)

		return -EOPNOTSUPP;



	if (!mmc_can_reset(card))

		return -EOPNOTSUPP;



	mmc_host_clk_hold(host);

	if ((host->caps & MMC_CAP_HW_RESET) && host->ops->hw_reset &&

	     mmc_can_reset(card)) {

		/* If the card accept RST_n signal, send it. */

		mmc_set_clock(host, host->f_init);



		host->ops->hw_reset(host);



		/* Set initial state and call mmc_set_ios */

		mmc_set_initial_state(host);

	mmc_host_clk_release(host);



	} else {

		/* Do a brute force power cycle */

		mmc_power_cycle(host, card->ocr);

	}

	return mmc_init_card(host, card->ocr, card);

}