[PATCH v2] mmc: retry CMD1 in mmc_send_op_cond() until the eMMC is ready
From: Haibo Chen haibo.chen@nxp.com
According to eMMC specification v5.1 section 6.4.3, we should issue CMD1 repeatedly in the idle state until the eMMC is ready even if mmc_send_op_cond() send CMD1 with argument = 0. Otherwise some eMMC devices seems to enter the inactive mode after mmc_complete_op_cond() issued CMD0 when the eMMC device is busy.
Signed-off-by: Haibo Chen haibo.chen@nxp.com --- drivers/mmc/mmc.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/drivers/mmc/mmc.c b/drivers/mmc/mmc.c index 85762b82e0..475f75fc64 100644 --- a/drivers/mmc/mmc.c +++ b/drivers/mmc/mmc.c @@ -662,12 +662,15 @@ static int mmc_send_op_cond_iter(struct mmc *mmc, int use_arg) static int mmc_send_op_cond(struct mmc *mmc) { int err, i; + int timeout = 1000; + uint start;
/* Some cards seem to need this */ mmc_go_idle(mmc);
+ start = get_timer(0); /* Asking to the card its capabilities */ - for (i = 0; i < 2; i++) { + for (i = 0; ; i++) { err = mmc_send_op_cond_iter(mmc, i != 0); if (err) return err; @@ -675,6 +678,10 @@ static int mmc_send_op_cond(struct mmc *mmc) /* exit if not busy (flag seems to be inverted) */ if (mmc->ocr & OCR_BUSY) break; + + if (get_timer(start) > timeout) + return -ETIMEDOUT; + udelay(100); } mmc->op_cond_pending = 1; return 0;
Subject: [PATCH v2] mmc: retry CMD1 in mmc_send_op_cond() until the eMMC is ready
From: Haibo Chen haibo.chen@nxp.com
According to eMMC specification v5.1 section 6.4.3, we should issue CMD1 repeatedly in the idle state until the eMMC is ready even if mmc_send_op_cond() send CMD1 with argument = 0. Otherwise some eMMC devices seems to enter the inactive mode after mmc_complete_op_cond() issued CMD0 when the eMMC device is busy.
Signed-off-by: Haibo Chen haibo.chen@nxp.com
drivers/mmc/mmc.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/drivers/mmc/mmc.c b/drivers/mmc/mmc.c index 85762b82e0..475f75fc64 100644 --- a/drivers/mmc/mmc.c +++ b/drivers/mmc/mmc.c @@ -662,12 +662,15 @@ static int mmc_send_op_cond_iter(struct mmc *mmc, int use_arg) static int mmc_send_op_cond(struct mmc *mmc) { int err, i;
int timeout = 1000;
uint start;
/* Some cards seem to need this */ mmc_go_idle(mmc);
start = get_timer(0); /* Asking to the card its capabilities */
- for (i = 0; i < 2; i++) {
- for (i = 0; ; i++) { err = mmc_send_op_cond_iter(mmc, i != 0); if (err) return err;
@@ -675,6 +678,10 @@ static int mmc_send_op_cond(struct mmc *mmc) /* exit if not busy (flag seems to be inverted) */ if (mmc->ocr & OCR_BUSY) break;
if (get_timer(start) > timeout)return -ETIMEDOUT;udelay(100);
The Linux code use 10ms delay, but it should be fine here.
Reviewed-by: Peng Fan peng.fan@nxp.com
} mmc->op_cond_pending = 1; return 0; -- 2.17.1
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