mmc: sdhci-of-dwcmshc: th1520: Increase tuning loop count to 128

commit ace323f80b9bc6734289a4e8a77938a3ce964c7d upstream.

Fix SD card tuning error by increasing tuning loop count
from 40(MAX_TUNING_LOOP) to 128.

For some reason the tuning algorithm requires to move through all the taps
of delay line even if the THRESHOLD_MODE (bit 2 in AT_CTRL_R) is used
instead of the LARGEST_WIN_MODE.

Tested-by: Drew Fustini <drew@pdp7.com>
Tested-by: Xi Ruoyao <xry111@xry111.site>
Signed-off-by: Maksim Kiselev <bigunclemax@gmail.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Fixes: 43658a542ebf ("mmc: sdhci-of-dwcmshc: Add support for T-Head TH1520")
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20240402093539.184287-1-bigunclemax@gmail.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/mmc/host/sdhci-of-dwcmshc.c b/drivers/mmc/host/sdhci-of-dwcmshc.c
index fa29460fd290394170218f267532bbdcd3430956..60b42126a4edbc462f27494b130bbea573aac6a0 100644 (file)
--- a/drivers/mmc/host/sdhci-of-dwcmshc.c
+++ b/drivers/mmc/host/sdhci-of-dwcmshc.c
@@ -612,6 +612,7 @@ static int th1520_execute_tuning(struct sdhci_host *host, u32 opcode)
 
        /* perform tuning */
        sdhci_start_tuning(host);
+       host->tuning_loop_count = 128;
        host->tuning_err = __sdhci_execute_tuning(host, opcode);
        if (host->tuning_err) {
                /* disable auto-tuning upon tuning error */