When the host->tuning_count is zero it means that the
retuning is disabled. This is checked on the first
run of sdhci_execute_tuning() by the if statement below:

        if (!(host->flags & SDHCI_NEEDS_RETUNING) && host->tuning_count &&
            (host->tuning_mode == SDHCI_TUNING_MODE_1)) {

So only when tuning_count is non-zero it will set the host
flag SDHCI_USING_RETUNING_TIMER. The else statement is only
for re-programming the timer, which means that flag must be
set. Because that is not checked the else statement is executed
in the first run when tuning_count is zero.

This was seen on a host controller which indicated
SDHCI_TUNING_MODE_1 (0) and tuning_count being zero. Suspect
that (one of) these registers is not properly set.

Signed-off-by: Arend van Spriel <[email protected]>
---
It has been a while looking at this, but I believe I never sent
a V3 of this patch so here it is. This patch applies to the
mmc-next branch.

V3:
- remote tuning mode check for retuning timer reload

V2:
- add more explanation to the commit message
- check host flag SDHCI_USING_RETUNING_TIMER
---
 drivers/mmc/host/sdhci.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index cc00bed..058b7de 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -2026,12 +2026,11 @@ out:
                        host->tuning_count * HZ);
                /* Tuning mode 1 limits the maximum data length to 4MB */
                mmc->max_blk_count = (4 * 1024 * 1024) / mmc->max_blk_size;
-       } else {
+       } else if (host->flags & SDHCI_USING_RETUNING_TIMER) {
                host->flags &= ~SDHCI_NEEDS_RETUNING;
                /* Reload the new initial value for timer */
-               if (host->tuning_mode == SDHCI_TUNING_MODE_1)
-                       mod_timer(&host->tuning_timer, jiffies +
-                               host->tuning_count * HZ);
+               mod_timer(&host->tuning_timer, jiffies +
+                         host->tuning_count * HZ);
        }
 
        /*
-- 
1.8.1.3

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