mmc: core: Do regular power cycle when lacking eMMC HW reset support (4e6c7178) · Commits · 戴 / test

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:

Gwendal Grignou <gwendal@chromium.org> [Ulf: Rewrote changelog] Signed-off-by:

Ulf Hansson <ulf.hansson@linaro.org>

drivers/mmc/core/core.c

+3 −2

Original line number	Diff line number	Diff line
		@@ -2456,8 +2456,9 @@ 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 −13

Original line number	Diff line number	Diff line
		@@ -1957,19 +1957,17 @@ 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;

		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);

		} else {
		/* Do a brute force power cycle */
		mmc_power_cycle(host, card->ocr);
		}
		return mmc_init_card(host, card->ocr, card);
		}

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