mmc: renesas_sdhi: Fix sampling clock position selecting

When tuning each tap is issued CMD19 twice and the result of both runs
recorded in host->taps. If the result is different between the two runs
the wrong sampling clock position was selected. Fix this by merging the
two runs and only keep the result for each tap if it was good in both
sets.
Signed-off-by: NNiklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Reviewed-by: NSimon Horman <horms+renesas@verge.net.au>
Tested-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

drivers/mmc/host/renesas_sdhi_core.c

@@ -384,6 +384,18 @@ static int renesas_sdhi_select_tuning(struct tmio_mmc_host *host)
 	/* Clear SCC_RVSREQ */
 	sd_scc_write32(host, priv, SH_MOBILE_SDHI_SCC_RVSREQ, 0);
 
+	/*
+	 * When tuning CMD19 is issued twice for each tap, merge the
+	 * result requiring the tap to be good in both runs before
+	 * considering it for tuning selection.
+	 */
+	for (i = 0; i < host->tap_num * 2; i++) {
+		int offset = host->tap_num * (i < host->tap_num ? 1 : -1);
+
+		if (!test_bit(i, host->taps))
+			clear_bit(i + offset, host->taps);
+	}
+
 	/*
 	 * Find the longest consecutive run of successful probes.  If that
 	 * is more than SH_MOBILE_SDHI_MAX_TAP probes long then use the