mmc: sd: reduce the bus speed in case of multiple CRC errors in SDR104
UHS-I SD cards support SDR104 mode which runs the SD card interface
clock upto 208 MHz. But we may see repeated CRC errors in SDR104
with some SDCC controllers. If this happens, this change would
reinit the card to lower speed (SDR50) hoping that CRC error
rate would reduce at lower clock speed (100MHz for SDR50).
Change-Id: I140d29fdf500bb89881a0f2c1f768fe0c5afa9d5
Signed-off-by: Asutosh Das <asutoshd@codeaurora.org>
Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>
diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c
index bcc296b..d8e9599 100644
--- a/drivers/mmc/card/block.c
+++ b/drivers/mmc/card/block.c
@@ -2200,6 +2200,17 @@
int need_retune = card->host->need_retune;
int ecc_err = 0, gen_err = 0;
+ if (card->host->sdr104_wa && mmc_card_sd(card) &&
+ (card->host->ios.timing == MMC_TIMING_UHS_SDR104) &&
+ !card->sdr104_blocked &&
+ (brq->data.error == -EILSEQ ||
+ brq->data.error == -EIO ||
+ brq->data.error == -ETIMEDOUT ||
+ brq->cmd.error == -EILSEQ ||
+ brq->cmd.error == -EIO ||
+ brq->cmd.error == -ETIMEDOUT))
+ card->err_in_sdr104 = true;
+
/*
* sbc.error indicates a problem with the set block count
* command. No data will have been transferred.
@@ -3640,6 +3651,7 @@
struct mmc_async_req *areq;
const u8 packed_nr = 2;
u8 reqs = 0;
+ bool reset = false;
#ifdef CONFIG_MMC_SIMULATE_MAX_SPEED
unsigned long waitfor = jiffies;
#endif
@@ -3685,6 +3697,26 @@
type = rq_data_dir(req) == READ ? MMC_BLK_READ : MMC_BLK_WRITE;
mmc_queue_bounce_post(mq_rq);
+ if (card->err_in_sdr104) {
+ /*
+ * Data CRC/timeout errors will manifest as CMD/DATA
+ * ERR. But we'd like to retry these too.
+ * Moreover, no harm done if this fails too for multiple
+ * times, we anyway reduce the bus-speed and retry the
+ * same request.
+ * If that fails too, we don't override this status.
+ */
+ if (status == MMC_BLK_ABORT ||
+ status == MMC_BLK_CMD_ERR ||
+ status == MMC_BLK_DATA_ERR ||
+ status == MMC_BLK_RETRY)
+ /* reset on all of these errors and retry */
+ reset = true;
+
+ status = MMC_BLK_RETRY;
+ card->err_in_sdr104 = false;
+ }
+
switch (status) {
case MMC_BLK_SUCCESS:
case MMC_BLK_PARTIAL:
@@ -3725,8 +3757,32 @@
break;
case MMC_BLK_RETRY:
retune_retry_done = brq->retune_retry_done;
- if (retry++ < MMC_BLK_MAX_RETRIES)
+ if (retry++ < MMC_BLK_MAX_RETRIES) {
break;
+ } else if (reset) {
+ reset = false;
+ /*
+ * If we exhaust all the retries due to
+ * CRC/timeout errors in SDR140 mode with UHS SD
+ * cards, re-configure the card in SDR50
+ * bus-speed mode.
+ * All subsequent re-init of this card will be
+ * in SDR50 mode, unless it is removed and
+ * re-inserted. When new UHS SD cards are
+ * inserted, it may start at SDR104 mode if
+ * supported by the card.
+ */
+ pr_err("%s: blocked SDR104, lower the bus-speed (SDR50 / DDR50)\n",
+ req->rq_disk->disk_name);
+ mmc_host_clear_sdr104(card->host);
+ mmc_suspend_clk_scaling(card->host);
+ mmc_blk_reset(md, card->host, type);
+ /* SDR104 mode is blocked from now on */
+ card->sdr104_blocked = true;
+ /* retry 5 times again */
+ retry = 0;
+ break;
+ }
/* Fall through */
case MMC_BLK_ABORT:
if (!mmc_blk_reset(md, card->host, type) &&