diff options
Diffstat (limited to 'src/drivers/storage/sd.c')
| -rw-r--r-- | src/drivers/storage/sd.c | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/src/drivers/storage/sd.c b/src/drivers/storage/sd.c index 18d2c0e245..6f4887a1a1 100644 --- a/src/drivers/storage/sd.c +++ b/src/drivers/storage/sd.c @@ -136,6 +136,7 @@ static void sd_recalculate_clock(struct storage_media *media) int sd_change_freq(struct storage_media *media) { + int delay; int err, timeout; struct mmc_command cmd; struct sd_mmc_ctrlr *ctrlr = media->ctrlr; @@ -225,11 +226,23 @@ int sd_change_freq(struct storage_media *media) if (!((ctrlr->caps & DRVR_CAP_HS52) && (ctrlr->caps & DRVR_CAP_HS))) goto out; + /* Give the card time to recover afer the switch operation. Wait for + * 9 (>= 8) clock cycles receiving the switch status. + */ + delay = (9000000 + ctrlr->bus_hz - 1) / ctrlr->bus_hz; + udelay(delay); + + /* Switch to high speed */ err = sd_switch(ctrlr, SD_SWITCH_SWITCH, 0, 1, (uint8_t *)switch_status); if (err) return err; + /* Give the card time to perform the switch operation. Wait for 9 + * (>= 8) clock cycles receiving the switch status. + */ + udelay(delay); + if ((ntohl(switch_status[4]) & 0x0f000000) == 0x01000000) { media->caps |= DRVR_CAP_HS; SET_TIMING(ctrlr, BUS_TIMING_SD_HS); |