On 5/19/20 12:37 PM, Peng Fan wrote:
Subject: [PATCH] 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. This patch also align with Linux 5.7.
Well, i think that it can't compare to linux driver. is your issue fixed with this patch?
As i know, this sequence is not follow correct spec. To enhance boot, it was skipping the polling time. If there is a problem, could you explain in more detail? Then I will also check on my targets.
Signed-off-by: Haibo Chen haibo.chen@nxp.com
drivers/mmc/mmc.c | 41 +++++++++++++++++++++++++++++++++-------- 1 file changed, 33 insertions(+), 8 deletions(-)
diff --git a/drivers/mmc/mmc.c b/drivers/mmc/mmc.c index 523c055967..509549756b 100644 --- a/drivers/mmc/mmc.c +++ b/drivers/mmc/mmc.c @@ -664,21 +664,46 @@ static int mmc_send_op_cond_iter(struct mmc *mmc, int use_arg)
static int mmc_send_op_cond(struct mmc *mmc) {
struct mmc_cmd cmd; int err, i;
int timeout = 1000;
ulong start;
/* Some cards seem to need this */ mmc_go_idle(mmc);
- /* Asking to the card its capabilities */
- for (i = 0; i < 2; i++) {
err = mmc_send_op_cond_iter(mmc, i != 0);
- cmd.cmdidx = MMC_CMD_SEND_OP_COND;
- cmd.resp_type = MMC_RSP_R3;
- cmd.cmdarg = 0;
- start = get_timer(0);
- /*
* According to eMMC specification v5.1 section 6.4.3, we* should issue CMD1 repeatedly in the idle state until* the eMMC is ready. Otherwise some eMMC devices seem to enter* the inactive mode after mmc_complete_op_cond() issued CMD0when
* the eMMC device is busy.*/Could we just extend the previous for loop to fix the issue? Your piece code duplicate much of the code and changed the original behavior.
- while (1) {
err = mmc_send_cmd(mmc, &cmd, NULL);
/* exit if not busy (flag seems to be inverted) */if (mmc->ocr & OCR_BUSY)break;
if (mmc_host_is_spi(mmc)) {if (!(cmd.response[0] & (1 << 0)))break;} else {mmc->ocr = cmd.response[0];/* exit if not busy (flag seems to be inverted) */if (mmc->ocr & OCR_BUSY)break;}if (get_timer(start) > timeout)return -EOPNOTSUPP;TIMEOUT, please.
udelay(100);This will change the original behavior by adding a delay.
if (!mmc_host_is_spi(mmc))cmd.cmdarg = cmd.response[0] | (1 << 30);Do we need "1 << 30" ?
}
- mmc->op_cond_pending = 1; return 0;
} @@ -691,7 +716,7 @@ static int mmc_complete_op_cond(struct mmc *mmc) int err;
mmc->op_cond_pending = 0;
- if (!(mmc->ocr & OCR_BUSY)) {
- if (mmc->ocr & OCR_BUSY) {
When card not go out busy, it means card not finish power up seq. Why drop !?
Right. It doesn't finish power-ups seq. If it's working with this patch, it seems something wrong.
/* Some cards seem to need this */ mmc_go_idle(mmc);--
Would the following patch help?
yes. it's more better. If need to increase polling time, i think it's correct place in mmc_complete_op_cond().
Best Regards, Jaehoon Chung
diff --git a/drivers/mmc/mmc.c b/drivers/mmc/mmc.c index 523c055967..d3a0538cdb 100644 --- a/drivers/mmc/mmc.c +++ b/drivers/mmc/mmc.c @@ -665,12 +665,15 @@ 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;ulong 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;@@ -678,6 +681,9 @@ 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; } mmc->op_cond_pending = 1; return 0;Thanks, Peng.
2.17.1