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Commit 385e3227 authored by Pierre Ossman's avatar Pierre Ossman Committed by Russell King
Browse files

[MMC] Fix SD timeout calculation 



Secure Digital cards use a different algorithm to calculate the timeout
for data transfers. Using the MMC one works often, but not always.

Signed-off-by: default avatarPierre Ossman <drzeus@drzeus.cx>
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent f57b225e

drivers/mmc/mmc.c

+13 −2
Original line number Diff line number Diff line
@@ -912,6 +912,7 @@ static void mmc_read_scrs(struct mmc_host *host) 
	struct mmc_request mrq;

	struct mmc_command cmd;

	struct mmc_data data;

	unsigned int timeout_us;



	struct scatterlist sg;
@@ -947,8 +948,18 @@ static void mmc_read_scrs(struct mmc_host *host) 


		memset(&data, 0, sizeof(struct mmc_data));



		data.timeout_ns = card->csd.tacc_ns * 10;

		data.timeout_clks = card->csd.tacc_clks * 10;

		data.timeout_ns = card->csd.tacc_ns * 100;

		data.timeout_clks = card->csd.tacc_clks * 100;



		timeout_us = data.timeout_ns / 1000;

		timeout_us += data.timeout_clks * 1000 /

			(host->ios.clock / 1000);



		if (timeout_us > 100000) {

			data.timeout_ns = 100000000;

			data.timeout_clks = 0;

		}



		data.blksz_bits = 3;

		data.blksz = 1 << 3;

		data.blocks = 1;

drivers/mmc/mmc_block.c

+36 −8
Original line number Diff line number Diff line
@@ -30,6 +30,7 @@ 
#include <linux/mutex.h>



#include <linux/mmc/card.h>

#include <linux/mmc/host.h>

#include <linux/mmc/protocol.h>



#include <asm/system.h>
@@ -171,8 +172,6 @@ static int mmc_blk_issue_rq(struct mmc_queue *mq, struct request *req) 


		brq.cmd.arg = req->sector << 9;

		brq.cmd.flags = MMC_RSP_R1 | MMC_CMD_ADTC;

		brq.data.timeout_ns = card->csd.tacc_ns * 10;

		brq.data.timeout_clks = card->csd.tacc_clks * 10;

		brq.data.blksz_bits = md->block_bits;

		brq.data.blksz = 1 << md->block_bits;

		brq.data.blocks = req->nr_sectors >> (md->block_bits - 9);
@@ -180,6 +179,41 @@ static int mmc_blk_issue_rq(struct mmc_queue *mq, struct request *req) 
		brq.stop.arg = 0;

		brq.stop.flags = MMC_RSP_R1B | MMC_CMD_AC;



		brq.data.timeout_ns = card->csd.tacc_ns * 10;

		brq.data.timeout_clks = card->csd.tacc_clks * 10;



		/*

		 * Scale up the timeout by the r2w factor

		 */

		if (rq_data_dir(req) == WRITE) {

			brq.data.timeout_ns <<= card->csd.r2w_factor;

			brq.data.timeout_clks <<= card->csd.r2w_factor;

		}



		/*

		 * SD cards use a 100 multiplier and has a upper limit

		 */

		if (mmc_card_sd(card)) {

			unsigned int limit_us, timeout_us;



			brq.data.timeout_ns *= 10;

			brq.data.timeout_clks *= 10;



			if (rq_data_dir(req) == READ)

				limit_us = 100000;

			else

				limit_us = 250000;



			timeout_us = brq.data.timeout_ns / 1000;

			timeout_us += brq.data.timeout_clks * 1000 /

				(card->host->ios.clock / 1000);



			if (timeout_us > limit_us) {

				brq.data.timeout_ns = limit_us * 1000;

				brq.data.timeout_clks = 0;

			}

		}



		if (rq_data_dir(req) == READ) {

			brq.cmd.opcode = brq.data.blocks > 1 ? MMC_READ_MULTIPLE_BLOCK : MMC_READ_SINGLE_BLOCK;

			brq.data.flags |= MMC_DATA_READ;
@@ -187,12 +221,6 @@ static int mmc_blk_issue_rq(struct mmc_queue *mq, struct request *req) 
			brq.cmd.opcode = MMC_WRITE_BLOCK;

			brq.data.flags |= MMC_DATA_WRITE;

			brq.data.blocks = 1;



			/*

			 * Scale up the timeout by the r2w factor

			 */

			brq.data.timeout_ns <<= card->csd.r2w_factor;

			brq.data.timeout_clks <<= card->csd.r2w_factor;

		}



		if (brq.data.blocks > 1) {