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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>
This commit is contained in:
Kuninori Morimoto 2014-09-02 19:08:53 -07:00 committed by Ulf Hansson
parent adc828556d
commit 2e47e84245
2 changed files with 17 additions and 0 deletions
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10
drivers/mmc/card/block.c
View File

@ -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) {

7
include/linux/mmc/host.h
View File

@ -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;