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Date: Sun, 01 Oct 2006 14:42:57 +0200
From: Pierre Ossman <drzeus@...eus.cx>
To: rmk+lkml@....linux.org.uk
Cc: linux-kernel@...r.kernel.org
Subject: [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@...eus.cx>
---
drivers/mmc/mmc_block.c | 104 ++++++++++++++++++++++++++++++++++++++----
include/linux/mmc/protocol.h | 1
2 files changed, 96 insertions(+), 9 deletions(-)
diff --git a/drivers/mmc/mmc_block.c b/drivers/mmc/mmc_block.c
index c1293f1..f9027c8 100644
--- a/drivers/mmc/mmc_block.c
+++ b/drivers/mmc/mmc_block.c
@@ -28,6 +28,7 @@ #include <linux/hdreg.h>
#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_qu
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_q
/*
* 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 @@ #endif
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,
diff --git a/include/linux/mmc/protocol.h b/include/linux/mmc/protocol.h
index 81c3f77..08dec8d 100644
--- a/include/linux/mmc/protocol.h
+++ b/include/linux/mmc/protocol.h
@@ -83,6 +83,7 @@ #define SD_SEND_RELATIVE_ADDR 3 /*
/* 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 */
-
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