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mmc: if possible, poll the busy state using DAT0

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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>
This commit is contained in:
Jean-Jacques Hiblot
2019-07-02 10:53:53 +02:00
committed by Peng Fan
parent 863d10044a
commit cd0b80ec9c
3 changed files with 4 additions and 6 deletions
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2
drivers/mmc/mmc-uclass.c
View File

@@ -47,7 +47,6 @@ int mmc_set_ios(struct mmc *mmc)
return dm_mmc_set_ios(mmc->dev); 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) int dm_mmc_wait_dat0(struct udevice *dev, int state, int timeout)
{ {
struct dm_mmc_ops *ops = mmc_get_ops(dev); struct dm_mmc_ops *ops = mmc_get_ops(dev);
@@ -61,7 +60,6 @@ int mmc_wait_dat0(struct mmc *mmc, int state, int timeout)
{ {
return dm_mmc_wait_dat0(mmc->dev, state, timeout); return dm_mmc_wait_dat0(mmc->dev, state, timeout);
} }
#endif
int dm_mmc_get_wp(struct udevice *dev) int dm_mmc_get_wp(struct udevice *dev)
{ {

6
drivers/mmc/mmc.c
View File

@@ -29,12 +29,10 @@ static int mmc_select_mode_and_width(struct mmc *mmc, uint card_caps);
#if !CONFIG_IS_ENABLED(DM_MMC) #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) static int mmc_wait_dat0(struct mmc *mmc, int state, int timeout)
{ {
return -ENOSYS; return -ENOSYS;
} }
#endif
__weak int board_mmc_getwp(struct mmc *mmc) __weak int board_mmc_getwp(struct mmc *mmc)
{ {
@@ -233,6 +231,10 @@ int mmc_poll_for_busy(struct mmc *mmc, int timeout)
unsigned int status; unsigned int status;
int err; int err;
err = mmc_wait_dat0(mmc, 1, timeout);
if (err != -ENOSYS)
return err;
while (1) { while (1) {
err = mmc_send_status(mmc, &status); err = mmc_send_status(mmc, &status);
if (err) if (err)

2
include/mmc.h
View File

@@ -445,7 +445,6 @@ struct dm_mmc_ops {
int (*execute_tuning)(struct udevice *dev, uint opcode); int (*execute_tuning)(struct udevice *dev, uint opcode);
#endif #endif
#if CONFIG_IS_ENABLED(MMC_UHS_SUPPORT)
/** /**
* wait_dat0() - wait until dat0 is in the target state * wait_dat0() - wait until dat0 is in the target state
* (CLK must be running during the wait) * (CLK must be running during the wait)
@@ -456,7 +455,6 @@ struct dm_mmc_ops {
* @return 0 if dat0 is in the target state, -ve on error * @return 0 if dat0 is in the target state, -ve on error
*/ */
int (*wait_dat0)(struct udevice *dev, int state, int timeout); int (*wait_dat0)(struct udevice *dev, int state, int timeout);
#endif
}; };
#define mmc_get_ops(dev) ((struct dm_mmc_ops *)(dev)->driver->ops) #define mmc_get_ops(dev) ((struct dm_mmc_ops *)(dev)->driver->ops)