linux-kernel - [PATCH v2] mmc: sdhci: Don't enable presets while tuning

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Date:   Mon, 24 Aug 2020 12:21:48 -0600
From:   Raul E Rangel <rrangel@...omium.org>
To:     adrian.hunter@...el.com
Cc:     Nehal-bakulchandra.Shah@....com, chris.wang@....com,
        Akshu.Agrawal@....com, Raul E Rangel <rrangel@...omium.org>,
        Jisheng Zhang <jszhang@...vell.com>,
        Ulf Hansson <ulf.hansson@...aro.org>,
        clang-built-linux@...glegroups.com, linux-kernel@...r.kernel.org,
        linux-mmc@...r.kernel.org
Subject: [PATCH v2] mmc: sdhci: Don't enable presets while tuning

SDHCI presets are not currently used for eMMC HS/HS200/HS400, but are
used for DDR52. The HS400 retuning sequence is:

    HS400->DDR52->HS->HS200->Perform Tuning->HS->HS400

This means that when HS400 tuning happens, we transition through DDR52
for a very brief period. This causes presets to be enabled
unintentionally and stay enabled when transitioning back to HS200 or
HS400.

This patch prevents enabling presets while tuning is in progress.

Fixes: 0dafa60eb2506 ("mmc: sdhci: also get preset value and driver type for MMC_DDR52")
Signed-off-by: Raul E Rangel <rrangel@...omium.org>
---
The indentation changed because I ran clang-format

Changes in v2:
- Fixed commit message. Patman didn't properly strip off the TEST= line.

 drivers/mmc/host/sdhci.c | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index 37b1158c1c0c9..fd702c436c165 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -2360,12 +2360,13 @@ void sdhci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
 		host->timing = ios->timing;
 
 		if (!(host->quirks2 & SDHCI_QUIRK2_PRESET_VALUE_BROKEN) &&
-				((ios->timing == MMC_TIMING_UHS_SDR12) ||
-				 (ios->timing == MMC_TIMING_UHS_SDR25) ||
-				 (ios->timing == MMC_TIMING_UHS_SDR50) ||
-				 (ios->timing == MMC_TIMING_UHS_SDR104) ||
-				 (ios->timing == MMC_TIMING_UHS_DDR50) ||
-				 (ios->timing == MMC_TIMING_MMC_DDR52))) {
+		    !mmc_doing_retune(mmc) &&
+		    ((ios->timing == MMC_TIMING_UHS_SDR12) ||
+		     (ios->timing == MMC_TIMING_UHS_SDR25) ||
+		     (ios->timing == MMC_TIMING_UHS_SDR50) ||
+		     (ios->timing == MMC_TIMING_UHS_SDR104) ||
+		     (ios->timing == MMC_TIMING_UHS_DDR50) ||
+		     (ios->timing == MMC_TIMING_MMC_DDR52))) {
 			u16 preset;
 
 			sdhci_enable_preset_value(host, true);
-- 
2.28.0.297.g1956fa8f8d-goog