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authorKuninori Morimoto <kuninori.morimoto.gx@renesas.com>2014-09-03 02:08:53 (GMT)
committerUlf Hansson <ulf.hansson@linaro.org>2014-09-09 11:59:25 (GMT)
commit2e47e84245adcb1b3872210678b6146f674fb3ff (patch)
tree0ab356fa3d0d079a855ed65e5b51326328738e99
parentadc828556dfc3f87a5c1338fc5412cbec3c0b529 (diff)
downloadlinux-2e47e84245adcb1b3872210678b6146f674fb3ff.tar.xz
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>
-rw-r--r--drivers/mmc/card/block.c10
-rw-r--r--include/linux/mmc/host.h7
2 files changed, 17 insertions, 0 deletions
diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c
index ede41f0..adab903 100644
--- a/drivers/mmc/card/block.c
+++ b/drivers/mmc/card/block.c
@@ -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) {
diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
index 4cbf614..10e2bd6 100644
--- a/include/linux/mmc/host.h
+++ b/include/linux/mmc/host.h
@@ -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;