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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Jaehoon Chung <jh80.chung@samsung.com>,
        Marek Szyprowski <m.szyprowski@samsung.com>,
        Christian Hewitt <christianshewitt@gmail.com>,
        Ulf Hansson <ulf.hansson@linaro.org>
Subject: [PATCH 5.4 17/51] mmc: dw_mmc: exynos: fix the finding clock sample value
Date:   Mon,  1 Nov 2021 10:17:21 +0100
Message-Id: <20211101082504.553979546@linuxfoundation.org>
In-Reply-To: <20211101082500.203657870@linuxfoundation.org>
References: <20211101082500.203657870@linuxfoundation.org>
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From: Jaehoon Chung <jh80.chung@samsung.com>

commit 697542bceae51f7620af333b065dd09d213629fb upstream.

Even though there are candiates value if can't find best value, it's
returned -EIO. It's not proper behavior.
If there is not best value, use a first candiate value to work eMMC.

Signed-off-by: Jaehoon Chung <jh80.chung@samsung.com>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Tested-by: Christian Hewitt <christianshewitt@gmail.com>
Cc: stable@vger.kernel.org
Fixes: c537a1c5ff63 ("mmc: dw_mmc: exynos: add variable delay tuning sequence")
Link: https://lore.kernel.org/r/20211022082106.1557-1-jh80.chung@samsung.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/mmc/host/dw_mmc-exynos.c |   14 ++++++++++++++
 1 file changed, 14 insertions(+)

--- a/drivers/mmc/host/dw_mmc-exynos.c
+++ b/drivers/mmc/host/dw_mmc-exynos.c
@@ -462,6 +462,18 @@ static s8 dw_mci_exynos_get_best_clksmpl
 		}
 	}
 
+	/*
+	 * If there is no cadiates value, then it needs to return -EIO.
+	 * If there are candiates values and don't find bset clk sample value,
+	 * then use a first candiates clock sample value.
+	 */
+	for (i = 0; i < iter; i++) {
+		__c = ror8(candiates, i);
+		if ((__c & 0x1) == 0x1) {
+			loc = i;
+			goto out;
+		}
+	}
 out:
 	return loc;
 }
@@ -492,6 +504,8 @@ static int dw_mci_exynos_execute_tuning(
 		priv->tuned_sample = found;
 	} else {
 		ret = -EIO;
+		dev_warn(&mmc->class_dev,
+			"There is no candiates value about clksmpl!\n");
 	}
 
 	return ret;