[MMC] Add multi block-write capability
Add a capability flag for drivers to set when they can perform multi-
block transfers to cards _and_ correctly report the number of bytes
transferred should an error occur.
The last point is very important - if a driver reports more bytes than
were actually accepted by the card and an error occurs, there is the
possibility for data loss.
Pierre Ossman provided the patch for wbsd and sdhci.
Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/drivers/mmc/mmc_block.c b/drivers/mmc/mmc_block.c
index f3a99dd..8d18b87 100644
--- a/drivers/mmc/mmc_block.c
+++ b/drivers/mmc/mmc_block.c
@@ -32,6 +32,7 @@
#include <linux/mmc/card.h>
#include <linux/mmc/host.h>
#include <linux/mmc/protocol.h>
+#include <linux/mmc/host.h>
#include <asm/system.h>
#include <asm/uaccess.h>
@@ -165,6 +166,7 @@
do {
struct mmc_blk_request brq;
struct mmc_command cmd;
+ u32 readcmd, writecmd;
memset(&brq, 0, sizeof(struct mmc_blk_request));
brq.mrq.cmd = &brq.cmd;
@@ -180,20 +182,31 @@
mmc_set_data_timeout(&brq.data, card, rq_data_dir(req) != READ);
- 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;
- } else {
- brq.cmd.opcode = MMC_WRITE_BLOCK;
- brq.data.flags |= MMC_DATA_WRITE;
+ /*
+ * If the host doesn't support multiple block writes, force
+ * block writes to single block.
+ */
+ if (rq_data_dir(req) != READ &&
+ !(card->host->caps & MMC_CAP_MULTIWRITE))
brq.data.blocks = 1;
- }
if (brq.data.blocks > 1) {
brq.data.flags |= MMC_DATA_MULTI;
brq.mrq.stop = &brq.stop;
+ readcmd = MMC_READ_MULTIPLE_BLOCK;
+ writecmd = MMC_WRITE_MULTIPLE_BLOCK;
} else {
brq.mrq.stop = NULL;
+ readcmd = MMC_READ_SINGLE_BLOCK;
+ writecmd = MMC_WRITE_BLOCK;
+ }
+
+ if (rq_data_dir(req) == READ) {
+ brq.cmd.opcode = readcmd;
+ brq.data.flags |= MMC_DATA_READ;
+ } else {
+ brq.cmd.opcode = writecmd;
+ brq.data.flags |= MMC_DATA_WRITE;
}
brq.data.sg = mq->sg;
