patches/1807-mmc-renesas_sdhi-Fix-sampling-clock-position-selecti.patch

From ad028d2f04f3d70abe1b63b1f64e3db8ed22a4be Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Niklas=20S=C3=B6derlund?=
 <niklas.soderlund+renesas@ragnatech.se>
Date: Tue, 24 Jul 2018 16:51:38 +0200
Subject: [PATCH 1807/1808] mmc: renesas_sdhi: Fix sampling clock position
 selecting
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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: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Reviewed-by: Simon Horman <horms+renesas@verge.net.au>
Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
(cherry picked from commit 5c99826b27d0afd4c05c2013385b17037f579cf9)
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
---
 drivers/mmc/host/renesas_sdhi_core.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/drivers/mmc/host/renesas_sdhi_core.c b/drivers/mmc/host/renesas_sdhi_core.c
index 45c015da2e75..f087ac728e35 100644
--- a/drivers/mmc/host/renesas_sdhi_core.c
+++ b/drivers/mmc/host/renesas_sdhi_core.c
@@ -301,6 +301,18 @@ 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
-- 
2.17.1