[PATCH 4/4] mmc: sunxi: Distinguish CRC and timeout errors

[Jernej Skrabec]

The driver reports every command and data error as -ETIMEDOUT. The MMC
core however relies on -EILSEQ to recognize CRC errors, which mean
that the sampling point drifted, and flags the host for retuning when
it sees one. With every error reported as a timeout, retuning is never
triggered.

Report response and data CRC, start bit and end bit errors as -EILSEQ
and keep reporting timeouts as -ETIMEDOUT, attributed to the command or
data phase that actually failed. Report any other error as -EIO.

Currently supported SoCs don't implement tuning, so this doesn't change
much for them, but it is needed for the upcoming A523 delay-chain
tuning support.

Signed-off-by: Jernej Skrabec <jernej.skrabec at gmail.com>
---
 drivers/mmc/host/sunxi-mmc.c | 20 ++++++++++++++++++--
 1 file changed, 18 insertions(+), 2 deletions(-)

diff --git a/drivers/mmc/host/sunxi-mmc.c b/drivers/mmc/host/sunxi-mmc.c
index b875ef4c2b79..eb1b7883a715 100644
--- a/drivers/mmc/host/sunxi-mmc.c
+++ b/drivers/mmc/host/sunxi-mmc.c
@@ -537,13 +537,29 @@ static irqreturn_t sunxi_mmc_finalize_request(struct sunxi_mmc_host *host)
 
 	if (host->int_sum & SDXC_INTERRUPT_ERROR_BIT) {
 		sunxi_mmc_dump_errinfo(host);
-		mrq->cmd->error = -ETIMEDOUT;
+
+		if (host->int_sum &
+		    (SDXC_RESP_ERROR | SDXC_RESP_CRC_ERROR))
+			mrq->cmd->error = -EILSEQ;
+		else if (host->int_sum & SDXC_RESP_TIMEOUT)
+			mrq->cmd->error = -ETIMEDOUT;
 
 		if (data) {
-			data->error = -ETIMEDOUT;
+			if (host->int_sum &
+			    (SDXC_DATA_CRC_ERROR | SDXC_START_BIT_ERROR |
+			     SDXC_END_BIT_ERROR))
+				data->error = -EILSEQ;
+			else if (host->int_sum &
+				 (SDXC_DATA_TIMEOUT | SDXC_FIFO_RUN_ERROR |
+				  SDXC_HARD_WARE_LOCKED))
+				data->error = -ETIMEDOUT;
+
 			host->manual_stop_mrq = mrq;
 		}
 
+		if (!mrq->cmd->error && (!data || !data->error))
+			mrq->cmd->error = -EIO;
+
 		if (mrq->stop)
 			mrq->stop->error = -ETIMEDOUT;
 	} else {
-- 
2.43.0