Commit 28f52482 authored by Anton Vorontsov's avatar Anton Vorontsov Committed by Pierre Ossman
Browse files

mmc: add support for card-detection polling 



Some hosts (and boards that use mmc_spi) do not use interrupts on the CD
line, so they can't trigger mmc_detect_change. We want to poll the card
and see if there was a change. 1 second poll interval seems resonable.

This patch also implements .get_cd() host operation, that could be used
by the hosts that are able to report card-detect status without need to
talk MMC.

Signed-off-by: default avatarAnton Vorontsov <avorontsov@ru.mvista.com>
Signed-off-by: default avatarPierre Ossman <drzeus@drzeus.cx>
parent 150a5568

drivers/mmc/core/core.c

+9 −3
Original line number Diff line number Diff line
@@ -638,6 +638,9 @@ void mmc_rescan(struct work_struct *work) 
		 */

		mmc_bus_put(host);



		if (host->ops->get_cd && host->ops->get_cd(host) == 0)

			goto out;



		mmc_claim_host(host);



		mmc_power_up(host);
@@ -652,7 +655,7 @@ void mmc_rescan(struct work_struct *work) 
		if (!err) {

			if (mmc_attach_sdio(host, ocr))

				mmc_power_off(host);

			return;

			goto out;

		}



		/*
@@ -662,7 +665,7 @@ void mmc_rescan(struct work_struct *work) 
		if (!err) {

			if (mmc_attach_sd(host, ocr))

				mmc_power_off(host);

			return;

			goto out;

		}



		/*
@@ -672,7 +675,7 @@ void mmc_rescan(struct work_struct *work) 
		if (!err) {

			if (mmc_attach_mmc(host, ocr))

				mmc_power_off(host);

			return;

			goto out;

		}



		mmc_release_host(host);
@@ -683,6 +686,9 @@ void mmc_rescan(struct work_struct *work) 


		mmc_bus_put(host);

	}

out:

	if (host->caps & MMC_CAP_NEEDS_POLL)

		mmc_schedule_delayed_work(&host->detect, HZ);

}



void mmc_start_host(struct mmc_host *host)

include/linux/mmc/host.h

+11 −0
Original line number Diff line number Diff line
@@ -51,8 +51,18 @@ struct mmc_ios { 


struct mmc_host_ops {

	void	(*request)(struct mmc_host *host, struct mmc_request *req);

	/*

	 * Avoid calling these three functions too often or in a "fast path",

	 * since underlaying controller might implement them in an expensive

	 * and/or slow way.

	 *

	 * Also note that these functions might sleep, so don't call them

	 * in the atomic contexts!

	 */

	void	(*set_ios)(struct mmc_host *host, struct mmc_ios *ios);

	int	(*get_ro)(struct mmc_host *host);

	int	(*get_cd)(struct mmc_host *host);



	void	(*enable_sdio_irq)(struct mmc_host *host, int enable);

};
@@ -94,6 +104,7 @@ struct mmc_host { 
#define MMC_CAP_SD_HIGHSPEED	(1 << 3)	/* Can do SD high-speed timing */

#define MMC_CAP_SDIO_IRQ	(1 << 4)	/* Can signal pending SDIO IRQs */

#define MMC_CAP_SPI		(1 << 5)	/* Talks only SPI protocols */

#define MMC_CAP_NEEDS_POLL	(1 << 6)	/* Needs polling for card-detection */



	/* host specific block data */

	unsigned int		max_seg_size;	/* see blk_queue_max_segment_size */

CRA Git | Maintained and supported by SUSTech CRA and CCSE