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From:   Jorge Ramirez-Ortiz <jorge@foundries.io>
To:     jorge@foundries.io, adrian.hunter@intel.com, Avri.Altman@wdc.com,
        ulf.hansson@linaro.org, christian.loehle@arm.com,
        ricardo@foundries.io
Cc:     linux-kernel@vger.kernel.org, linux-mmc@vger.kernel.org
Subject: [PATCH] mmc: rpmb: do not force a retune before RPMB switch
Date:   Mon, 11 Dec 2023 17:55:00 +0100
Message-Id: <20231211165500.310097-1-jorge@foundries.io>
MIME-Version: 1.0
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Precedence: bulk

Requesting a retune before switching to the RPMB partition has been
observed to cause CRC errors on the RPMB reads (-EILSEQ).

Since RPMB reads can not be retried, the clients would be directly
affected by the errors.

This commit disables the retune request prior to switching to the RPMB
partition: mmc_retune_pause() no longer triggers a retune before the
pause period begins.

This was verified with the sdhci-of-arasan driver (ZynqMP) configured
for HS200 using two separate eMMC cards (DG4064 and 064GB2). In both
cases, the error was easy to reproduce triggering every few tenths of
reads.

Signed-off-by: Jorge Ramirez-Ortiz <jorge@foundries.io>
Acked-by: Avri Altman <avri.altman@wdc.com>
---
 v2:
    mmc_retune_pause() no longer can trigger a retune.
    Keeping Avri Altman Acked-by since they are functionally equivalent.
 v1:
    modify mmc_retune_pause to optionally trigger a retune.

 drivers/mmc/core/host.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/mmc/core/host.c b/drivers/mmc/core/host.c
index 096093f7be00..ed44920e92df 100644
--- a/drivers/mmc/core/host.c
+++ b/drivers/mmc/core/host.c
@@ -119,13 +119,12 @@ void mmc_retune_enable(struct mmc_host *host)

 /*
  * Pause re-tuning for a small set of operations.  The pause begins after the
- * next command and after first doing re-tuning.
+ * next command.
  */
 void mmc_retune_pause(struct mmc_host *host)
 {
 	if (!host->retune_paused) {
 		host->retune_paused = 1;
-		mmc_retune_needed(host);
 		mmc_retune_hold(host);
 	}
 }
--
2.34.1