[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>

diff --git a/drivers/mmc/mmc_block.c b/drivers/mmc/mmc_block.c
index c1293f1..f9027c8 100644 (file)
--- a/drivers/mmc/mmc_block.c
+++ b/drivers/mmc/mmc_block.c
@@ -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,

diff --git a/include/linux/mmc/protocol.h b/include/linux/mmc/protocol.h
index 81c3f77..08dec8d 100644 (file)
--- a/include/linux/mmc/protocol.h
+++ b/include/linux/mmc/protocol.h
@@ -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  */