mmc: renesas_sdhi: Avoid bad TAP in HS400

With R-Car Gen3, CRC error occue at the following TAPs.

H3, M3W 1.3, M3N... TAP=2,3,6,7
M3W 3.0		... TAP=1,3,5,7

(Note: for 4tap SoCs, the numbers get divided by 2)

Do not use these TAPs in HS400, and also don't use auto correction but
manual correction.

We check for bad taps in two places:

1) After tuning HS400: Then, we select a neighbouring TAP. One of them
   must be good, because there are never three bad taps in a row.
   Retuning won't help because we just finished tuning.

2) After a manual correction request: Here, we can't switch to the
   requested TAP. But we can retune (if the HS200 tuning was good)
   because the environment might have changed since the last tuning.
   If not, we stay on the same TAP.

Signed-off-by: Takeshi Saito <takeshi.saito.xv@renesas.com>
[wsa: refactored to match upstream driver, reworded commit msg]
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Link: https://lore.kernel.org/r/20200423130432.9990-3-wsa+renesas@sang-engineering.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

1 files changed, 1 insertions, 0 deletions

diff --git a/drivers/mmc/host/renesas_sdhi.h b/drivers/mmc/host/renesas_sdhi.h
index 86efa9d5cd6d..14c64caefc64 100644
--- a/drivers/mmc/host/renesas_sdhi.h
+++ b/drivers/mmc/host/renesas_sdhi.h
@@ -36,6 +36,7 @@ struct renesas_sdhi_of_data {
 struct renesas_sdhi_quirks {
 	bool hs400_disabled;
 	bool hs400_4taps;
+	u32 hs400_bad_taps;
 };
 
 struct tmio_mmc_dma {