mmc: support packed write command for eMMC4.5 devices
This patch supports packed write command of eMMC4.5 devices. Several
writes can be grouped in packed command and all data of the individual
commands can be sent in a single transfer on the bus. Large amounts of
data in one transfer rather than several data of small size are
effective for eMMC write internally. As a result, packed command help
write throughput be improved. The following tables show the results
of packed write.
Type A:
test none | packed
iozone 25.8 | 31
tiotest 27.6 | 31.2
lmdd 31.2 | 35.4
Type B:
test none | packed
iozone 44.1 | 51.1
tiotest 47.9 | 52.5
lmdd 51.6 | 59.2
Type C:
test none | packed
iozone 19.5 | 32
tiotest 19.9 | 34.5
lmdd 22.8 | 40.7
Signed-off-by: Seungwon Jeon <tgih.jun@samsung.com>
Reviewed-by: Maya Erez <merez@codeaurora.org>
Reviewed-by: Namjae Jeon <linkinjeon@gmail.com>
Signed-off-by: Chris Ball <cjb@laptop.org>
diff --git a/include/linux/mmc/core.h b/include/linux/mmc/core.h
index 495d133..39613b9 100644
--- a/include/linux/mmc/core.h
+++ b/include/linux/mmc/core.h
@@ -18,6 +18,9 @@
struct mmc_command {
u32 opcode;
u32 arg;
+#define MMC_CMD23_ARG_REL_WR (1 << 31)
+#define MMC_CMD23_ARG_PACKED ((0 << 31) | (1 << 30))
+#define MMC_CMD23_ARG_TAG_REQ (1 << 29)
u32 resp[4];
unsigned int flags; /* expected response type */
#define MMC_RSP_PRESENT (1 << 0)
@@ -148,6 +151,7 @@
extern void mmc_start_bkops(struct mmc_card *card, bool from_exception);
extern int __mmc_switch(struct mmc_card *, u8, u8, u8, unsigned int, bool);
extern int mmc_switch(struct mmc_card *, u8, u8, u8, unsigned int);
+extern int mmc_send_ext_csd(struct mmc_card *card, u8 *ext_csd);
#define MMC_ERASE_ARG 0x00000000
#define MMC_SECURE_ERASE_ARG 0x80000000