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

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 <[email protected]>
Tested-by: Xi Ruoyao <[email protected]>
Signed-off-by: Maksim Kiselev <[email protected]>
Acked-by: Adrian Hunter <[email protected]>
Fixes: 43658a5 ("mmc: sdhci-of-dwcmshc: Add support for T-Head TH1520")
Cc: [email protected]
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Ulf Hansson <[email protected]>

Author: bigunclemax

drivers/mmc/host/sdhci-of-dwcmshc.c

@@ -626,6 +626,7 @@ 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 */