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[PATCH] mmc: multi sector write transfers 

SD cards extend the protocol by allowing the host to query a card how many
blocks were successfully stored on the medium.  This allows us to safely write
chunks of blocks at once.

Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Pierre Ossman 2006-10-06 00:44:03 -07:00 committed by Linus Torvalds
parent 45e02b5b52
commit ec5a19dd93
2 changed files with 96 additions and 9 deletions
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104
drivers/mmc/mmc_block.c
View File

@ -28,6 +28,7 @@
#include <linux/kdev_t.h>
#include <linux/blkdev.h>
#include <linux/mutex.h>
#include <linux/scatterlist.h>
#include <linux/mmc/card.h>
#include <linux/mmc/host.h>
@ -154,6 +155,71 @@ static int mmc_blk_prep_rq(struct mmc_queue *mq, struct request *req)
return stat;
}
static u32 mmc_sd_num_wr_blocks(struct mmc_card *card)
{
int err;
u32 blocks;
struct mmc_request mrq;
struct mmc_command cmd;
struct mmc_data data;
unsigned int timeout_us;
struct scatterlist sg;
memset(&cmd, 0, sizeof(struct mmc_command));
cmd.opcode = MMC_APP_CMD;
cmd.arg = card->rca << 16;
cmd.flags = MMC_RSP_R1 | MMC_CMD_AC;
err = mmc_wait_for_cmd(card->host, &cmd, 0);
if ((err != MMC_ERR_NONE) || !(cmd.resp[0] & R1_APP_CMD))
return (u32)-1;
memset(&cmd, 0, sizeof(struct mmc_command));
cmd.opcode = SD_APP_SEND_NUM_WR_BLKS;
cmd.arg = 0;
cmd.flags = MMC_RSP_R1 | MMC_CMD_ADTC;
memset(&data, 0, sizeof(struct mmc_data));
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 /
(card->host->ios.clock / 1000);
if (timeout_us > 100000) {
data.timeout_ns = 100000000;
data.timeout_clks = 0;
}
data.blksz = 4;
data.blocks = 1;
data.flags = MMC_DATA_READ;
data.sg = &sg;
data.sg_len = 1;
memset(&mrq, 0, sizeof(struct mmc_request));
mrq.cmd = &cmd;
mrq.data = &data;
sg_init_one(&sg, &blocks, 4);
mmc_wait_for_req(card->host, &mrq);
if (cmd.error != MMC_ERR_NONE || data.error != MMC_ERR_NONE)
return (u32)-1;
blocks = ntohl(blocks);
return blocks;
}
static int mmc_blk_issue_rq(struct mmc_queue *mq, struct request *req)
{
struct mmc_blk_data *md = mq->data;
@ -184,10 +250,13 @@ static int mmc_blk_issue_rq(struct mmc_queue *mq, struct request *req)
/*
* If the host doesn't support multiple block writes, force
* block writes to single block.
* block writes to single block. SD cards are excepted from
* this rule as they support querying the number of
* successfully written sectors.
*/
if (rq_data_dir(req) != READ &&
!(card->host->caps & MMC_CAP_MULTIWRITE))
!(card->host->caps & MMC_CAP_MULTIWRITE) &&
!mmc_card_sd(card))
brq.data.blocks = 1;
if (brq.data.blocks > 1) {
@ -276,24 +345,41 @@ static int mmc_blk_issue_rq(struct mmc_queue *mq, struct request *req)
return 1;
cmd_err:
mmc_card_release_host(card);
ret = 1;
/*
* For writes and where the host claims to support proper
* error reporting, we first ok the successful blocks.
/*
* If this is an SD card and we're writing, we can first
* mark the known good sectors as ok.
*
* If the card is not SD, we can still ok written sectors
* if the controller can do proper error reporting.
*
* For reads we just fail the entire chunk as that should
* be safe in all cases.
*/
if (rq_data_dir(req) != READ &&
(card->host->caps & MMC_CAP_MULTIWRITE)) {
if (rq_data_dir(req) != READ && mmc_card_sd(card)) {
u32 blocks;
unsigned int bytes;
blocks = mmc_sd_num_wr_blocks(card);
if (blocks != (u32)-1) {
if (card->csd.write_partial)
bytes = blocks << md->block_bits;
else
bytes = blocks << 9;
spin_lock_irq(&md->lock);
ret = end_that_request_chunk(req, 1, bytes);
spin_unlock_irq(&md->lock);
}
} else if (rq_data_dir(req) != READ &&
(card->host->caps & MMC_CAP_MULTIWRITE)) {
spin_lock_irq(&md->lock);
ret = end_that_request_chunk(req, 1, brq.data.bytes_xfered);
spin_unlock_irq(&md->lock);
}
mmc_card_release_host(card);
spin_lock_irq(&md->lock);
while (ret) {
ret = end_that_request_chunk(req, 0,

1
include/linux/mmc/protocol.h
View File

@ -83,6 +83,7 @@
/* Application commands */
#define SD_APP_SET_BUS_WIDTH 6 /* ac [1:0] bus width R1 */
#define SD_APP_SEND_NUM_WR_BLKS 22 /* adtc R1 */
#define SD_APP_OP_COND 41 /* bcr [31:0] OCR R3 */
#define SD_APP_SEND_SCR 51 /* adtc R1 */