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Commit 2e47e842 authored Sep 02, 2014 by Kuninori Morimoto Committed by Ulf Hansson Sep 09, 2014

mmc: Add .multi_io_quirk callback for multi I/O HW bug



Historically, we have been using MMC_CAP* to handle host HW issues and
currently the block layer uses MMC_CAP2_NO_MULTI_READ flag for a multi
I/O HW bug workaround.

There are a few tweaks needed to make MMC_CAP2_NO_MULTI_READ suite all
situations. Therefore let's add an optional host ops callback to enable
host drivers to return the number of blocks it allows per request.

In a future patch and when host drivers have converted to the new
callback, MMC_CAP2_NO_MULTI_READ shall be removed.

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

parent adc82855

drivers/mmc/card/block.c

+10 −0

Original line number	Diff line number	Diff line
		@@ -1402,6 +1402,16 @@ static void mmc_blk_rw_rq_prep(struct mmc_queue_req *mqrq,
		if (card->host->caps2 & MMC_CAP2_NO_MULTI_READ &&
		rq_data_dir(req) == READ)
		brq->data.blocks = 1;

		/*
		* Some controllers have HW issues while operating
		* in multiple I/O mode
		*/
		if (card->host->ops->multi_io_quirk)
		brq->data.blocks = card->host->ops->multi_io_quirk(card,
		(rq_data_dir(req) == READ) ?
		MMC_DATA_READ : MMC_DATA_WRITE,
		brq->data.blocks);
		}

		if (brq->data.blocks > 1 \|\| do_rel_wr) {

include/linux/mmc/host.h

+7 −0

Original line number	Diff line number	Diff line
		@@ -139,6 +139,13 @@ struct mmc_host_ops {
		int (*select_drive_strength)(unsigned int max_dtr, int host_drv, int card_drv);
		void (hw_reset)(struct mmc_host host);
		void (card_event)(struct mmc_host host);

		/*
		* Optional callback to support controllers with HW issues for multiple
		* I/O. Returns the number of supported blocks for the request.
		*/
		int (multi_io_quirk)(struct mmc_card card,
		unsigned int direction, int blk_size);
		};

		struct mmc_card;