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-rw-r--r--src/drivers/storage/sd.c13
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);