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Commit c6e633ad authored by Daniel Drake's avatar Daniel Drake Committed by Chris Ball
Browse files

mmc: sdio: reset card during power_restore 



mmc_sdio_power_restore() skips some steps that are performed in other
power-related codepaths which are necessary to fully reset the card.
Without this, runtime PM fails for SD8686 SDIO wifi on OLPC XO-1.5.

Signed-off-by: default avatarDaniel Drake <dsd@laptop.org>
Signed-off-by: default avatarChris Ball <cjb@laptop.org>
parent e9e8bcb8

drivers/mmc/core/sdio.c

+39 −0
Original line number Original line Diff line number Diff line
@@ -691,15 +691,54 @@ static int mmc_sdio_resume(struct mmc_host *host) 
static int mmc_sdio_power_restore(struct mmc_host *host)

static int mmc_sdio_power_restore(struct mmc_host *host)

{

{

	int ret;

	int ret;

	u32 ocr;





	BUG_ON(!host);

	BUG_ON(!host);

	BUG_ON(!host->card);

	BUG_ON(!host->card);





	mmc_claim_host(host);

	mmc_claim_host(host);



	/*

	 * Reset the card by performing the same steps that are taken by

	 * mmc_rescan_try_freq() and mmc_attach_sdio() during a "normal" probe.

	 *

	 * sdio_reset() is technically not needed. Having just powered up the

	 * hardware, it should already be in reset state. However, some

	 * platforms (such as SD8686 on OLPC) do not instantly cut power,

	 * meaning that a reset is required when restoring power soon after

	 * powering off. It is harmless in other cases.

	 *

	 * The CMD5 reset (mmc_send_io_op_cond()), according to the SDIO spec,

	 * is not necessary for non-removable cards. However, it is required

	 * for OLPC SD8686 (which expects a [CMD5,5,3,7] init sequence), and

	 * harmless in other situations.

	 *

	 * With these steps taken, mmc_select_voltage() is also required to

	 * restore the correct voltage setting of the card.

	 */

	sdio_reset(host);

	mmc_go_idle(host);

	mmc_send_if_cond(host, host->ocr_avail);



	ret = mmc_send_io_op_cond(host, 0, &ocr);

	if (ret)

		goto out;



	if (host->ocr_avail_sdio)

		host->ocr_avail = host->ocr_avail_sdio;



	host->ocr = mmc_select_voltage(host, ocr & ~0x7F);

	if (!host->ocr) {

		ret = -EINVAL;

		goto out;

	}



	ret = mmc_sdio_init_card(host, host->ocr, host->card,

	ret = mmc_sdio_init_card(host, host->ocr, host->card,

				mmc_card_keep_power(host));

				mmc_card_keep_power(host));

	if (!ret && host->sdio_irqs)

	if (!ret && host->sdio_irqs)

		mmc_signal_sdio_irq(host);

		mmc_signal_sdio_irq(host);



out:

	mmc_release_host(host);

	mmc_release_host(host);





	return ret;

	return ret;