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Commit 41591b38 authored by Chris Boot's avatar Chris Boot Committed by Ulf Hansson
Browse files

mmc: block: avoid multiblock reads for the last sector in SPI mode 



On some SD cards over SPI, reading with the multiblock read command the last
sector will leave the card in a bad state.

Remove last sectors from the multiblock reading cmd.

Signed-off-by: default avatarChris Boot <bootc@bootc.net>
Signed-off-by: default avatarClément Péron <peron.clem@gmail.com>
Cc: stable@vger.kernel.org # v4.10+
Signed-off-by: default avatarUlf Hansson <ulf.hansson@linaro.org>
parent 0238df64

drivers/mmc/core/block.c

+10 −0
Original line number Diff line number Diff line
@@ -1370,6 +1370,16 @@ static void mmc_blk_data_prep(struct mmc_queue *mq, struct mmc_queue_req *mqrq, 
		brq->data.blocks = card->host->max_blk_count;



	if (brq->data.blocks > 1) {

		/*

		 * Some SD cards in SPI mode return a CRC error or even lock up

		 * completely when trying to read the last block using a

		 * multiblock read command.

		 */

		if (mmc_host_is_spi(card->host) && (rq_data_dir(req) == READ) &&

		    (blk_rq_pos(req) + blk_rq_sectors(req) ==

		     get_capacity(md->disk)))

			brq->data.blocks--;



		/*

		 * After a read error, we redo the request one sector

		 * at a time in order to accurately determine which