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Commit 4e6c7178 authored by Gwendal Grignou's avatar Gwendal Grignou Committed by Ulf Hansson
Browse files

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.

Signed-off-by: default avatarGwendal Grignou <gwendal@chromium.org>
[Ulf: Rewrote changelog]
Signed-off-by: default avatarUlf Hansson <ulf.hansson@linaro.org>
parent 6aef2eec

drivers/mmc/core/core.c

+3 −2
Original line number Original line Diff line number Diff line
@@ -2456,8 +2456,9 @@ int mmc_hw_reset(struct mmc_host *host) 
	ret = host->bus_ops->reset(host);

	ret = host->bus_ops->reset(host);

	mmc_bus_put(host);

	mmc_bus_put(host);





	if (ret != -EOPNOTSUPP)

	if (ret)

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

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

			mmc_hostname(host), ret);





	return ret;

	return ret;

}

}

drivers/mmc/core/mmc.c

+11 −13
Original line number Original line Diff line number Diff line
@@ -1957,19 +1957,17 @@ static int mmc_reset(struct mmc_host *host) 
{

{

	struct mmc_card *card = host->card;

	struct mmc_card *card = host->card;





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

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

		return -EOPNOTSUPP;

	     mmc_can_reset(card)) {



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

	if (!mmc_can_reset(card))

		return -EOPNOTSUPP;



		mmc_set_clock(host, host->f_init);

		mmc_set_clock(host, host->f_init);



		host->ops->hw_reset(host);

		host->ops->hw_reset(host);



		/* Set initial state and call mmc_set_ios */

		/* Set initial state and call mmc_set_ios */

		mmc_set_initial_state(host);

		mmc_set_initial_state(host);



	} else {

		/* Do a brute force power cycle */

		mmc_power_cycle(host, card->ocr);

	}

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

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

}

}