mmc: if possible, poll the busy state using DAT0
Using the DAT0 line as a rdy/busy line is an alternative to reading the
status register of the card. It especially useful in situation where the
bus is not in a good shape, like when modes are switched.
This is also how the linux driver behaves.
Note of warning: As per the specification, while polling on DAT0 the CLK
must not turned off: "[...] Without a clock edge the Device (unless
previously disconnected by a deselect command (CMD7)) will force the DAT0
line down, forever. [...]"
Signed-off-by: Jean-Jacques Hiblot <jjhiblot@ti.com>
diff --git a/drivers/mmc/mmc-uclass.c b/drivers/mmc/mmc-uclass.c
index 923a3b1..9327c83 100644
--- a/drivers/mmc/mmc-uclass.c
+++ b/drivers/mmc/mmc-uclass.c
@@ -47,7 +47,6 @@
return dm_mmc_set_ios(mmc->dev);
}
-#if CONFIG_IS_ENABLED(MMC_UHS_SUPPORT)
int dm_mmc_wait_dat0(struct udevice *dev, int state, int timeout)
{
struct dm_mmc_ops *ops = mmc_get_ops(dev);
@@ -61,7 +60,6 @@
{
return dm_mmc_wait_dat0(mmc->dev, state, timeout);
}
-#endif
int dm_mmc_get_wp(struct udevice *dev)
{
diff --git a/drivers/mmc/mmc.c b/drivers/mmc/mmc.c
index 36cce79..a61e311 100644
--- a/drivers/mmc/mmc.c
+++ b/drivers/mmc/mmc.c
@@ -29,12 +29,10 @@
#if !CONFIG_IS_ENABLED(DM_MMC)
-#if CONFIG_IS_ENABLED(MMC_UHS_SUPPORT)
static int mmc_wait_dat0(struct mmc *mmc, int state, int timeout)
{
return -ENOSYS;
}
-#endif
__weak int board_mmc_getwp(struct mmc *mmc)
{
@@ -233,6 +231,10 @@
unsigned int status;
int err;
+ err = mmc_wait_dat0(mmc, 1, timeout);
+ if (err != -ENOSYS)
+ return err;
+
while (1) {
err = mmc_send_status(mmc, &status);
if (err)