diff options
| -rw-r--r-- | drivers/mmc/mmc.c | 16 |
1 files changed, 14 insertions, 2 deletions
diff --git a/drivers/mmc/mmc.c b/drivers/mmc/mmc.c index e5fedb3..3f59687 100644 --- a/drivers/mmc/mmc.c +++ b/drivers/mmc/mmc.c @@ -1179,7 +1179,7 @@ block_dev_desc_t *mmc_get_dev(int dev) int mmc_init(struct mmc *mmc) { - int err; + int err, retry = 3; if (mmc->has_init) return 0; @@ -1202,7 +1202,19 @@ int mmc_init(struct mmc *mmc) mmc->part_num = 0; /* Test for SD version 2 */ - err = mmc_send_if_cond(mmc); + /* + * retry here for 3 times, as for some controller it has dynamic + * clock gating, and only toggle out clk when the first cmd0 send + * out, while some card strictly obey the 74 clocks rule, the interval + * may not be sufficient between the cmd0 and this cmd8, retry to + * fulfil the clock requirement + */ + do { + err = mmc_send_if_cond(mmc); + } while (--retry > 0 && err); + + if (err) + return err; /* Now try to get the SD card's operating condition */ err = sd_send_op_cond(mmc); |