mmc: test mmc bus width on startup
For we don't know mmc bus width from reading registers, the only way
to check is to test.
Current compare offset is:
EXT_CSD_PARTITIONING_SUPPORT
EXT_CSD_ERASE_GROUP_DEF
EXT_CSD_REV
EXT_CSD_HC_ERASE_GRP_SIZE
EXT_CSD_SEC_CNT
Signed-off-by: Lei Wen <leiwen@marvell.com>
diff --git a/drivers/mmc/mmc.c b/drivers/mmc/mmc.c
index ac26db1..96facb7 100644
--- a/drivers/mmc/mmc.c
+++ b/drivers/mmc/mmc.c
@@ -631,8 +631,6 @@
if (mmc->version < MMC_VERSION_4)
return 0;
- mmc->card_caps |= MMC_MODE_4BIT;
-
err = mmc_send_ext_csd(mmc, ext_csd);
if (err)
@@ -856,11 +854,12 @@
int mmc_startup(struct mmc *mmc)
{
- int err;
+ int err, width;
uint mult, freq;
u64 cmult, csize, capacity;
struct mmc_cmd cmd;
ALLOC_CACHE_ALIGN_BUFFER(char, ext_csd, 512);
+ ALLOC_CACHE_ALIGN_BUFFER(char, test_csd, 512);
int timeout = 1000;
#ifdef CONFIG_MMC_SPI_CRC_ON
@@ -1080,26 +1079,35 @@
else
mmc_set_clock(mmc, 25000000);
} else {
- if (mmc->card_caps & MMC_MODE_4BIT) {
+ for (width = EXT_CSD_BUS_WIDTH_8; width >= 0; width--) {
/* Set the card to use 4 bit*/
err = mmc_switch(mmc, EXT_CSD_CMD_SET_NORMAL,
- EXT_CSD_BUS_WIDTH,
- EXT_CSD_BUS_WIDTH_4);
+ EXT_CSD_BUS_WIDTH, width);
if (err)
- return err;
+ continue;
- mmc_set_bus_width(mmc, 4);
- } else if (mmc->card_caps & MMC_MODE_8BIT) {
- /* Set the card to use 8 bit*/
- err = mmc_switch(mmc, EXT_CSD_CMD_SET_NORMAL,
- EXT_CSD_BUS_WIDTH,
- EXT_CSD_BUS_WIDTH_8);
+ if (!width) {
+ mmc_set_bus_width(mmc, 1);
+ break;
+ } else
+ mmc_set_bus_width(mmc, 4 * width);
- if (err)
- return err;
+ err = mmc_send_ext_csd(mmc, test_csd);
+ if (!err && ext_csd[EXT_CSD_PARTITIONING_SUPPORT] \
+ == test_csd[EXT_CSD_PARTITIONING_SUPPORT]
+ && ext_csd[EXT_CSD_ERASE_GROUP_DEF] \
+ == test_csd[EXT_CSD_ERASE_GROUP_DEF] \
+ && ext_csd[EXT_CSD_REV] \
+ == test_csd[EXT_CSD_REV]
+ && ext_csd[EXT_CSD_HC_ERASE_GRP_SIZE] \
+ == test_csd[EXT_CSD_HC_ERASE_GRP_SIZE]
+ && memcmp(&ext_csd[EXT_CSD_SEC_CNT], \
+ &test_csd[EXT_CSD_SEC_CNT], 4) == 0) {
- mmc_set_bus_width(mmc, 8);
+ mmc->card_caps |= width;
+ break;
+ }
}
if (mmc->card_caps & MMC_MODE_HS) {