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From:   Chunyan Zhang <zhang.lyra@gmail.com>
To:     Ulf Hansson <ulf.hansson@linaro.org>,
        Adrian Hunter <adrian.hunter@intel.com>
Cc:     linux-mmc@vger.kernel.org, Baolin Wang <baolin.wang7@gmail.com>,
        Orson Zhai <orsonzhai@gmail.com>,
        Chunyan Zhang <zhang.lyra@gmail.com>,
        Chunyan Zhang <chunyan.zhang@unisoc.com>,
        zhenxiong.lai@unisoc.com, yuelin.tang@unisoc.com,
        LKML <linux-kernel@vger.kernel.org>
Subject: [PATCH] mmc: sdhci-sprd: Wait until DLL locked after being configured
Date:   Thu, 23 Sep 2021 16:57:50 +0800
Message-Id: <20210923085750.71968-1-zhang.lyra@gmail.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

From: Zhenxiong Lai <zhenxiong.lai@unisoc.com>

According to the specification, DLL status has to be locked before using it.

Signed-off-by: Zhenxiong Lai <zhenxiong.lai@unisoc.com>
Signed-off-by: Chunyan Zhang <chunyan.zhang@unisoc.com>
---
 drivers/mmc/host/sdhci-sprd.c | 20 +++++++++++++++++++-
 1 file changed, 19 insertions(+), 1 deletion(-)

diff --git a/drivers/mmc/host/sdhci-sprd.c b/drivers/mmc/host/sdhci-sprd.c
index 11e375579cfb..83749c7a6db4 100644
--- a/drivers/mmc/host/sdhci-sprd.c
+++ b/drivers/mmc/host/sdhci-sprd.c
@@ -39,6 +39,9 @@
 #define  SDHCI_SPRD_BIT_POSRD_DLY_INV		BIT(21)
 #define  SDHCI_SPRD_BIT_NEGRD_DLY_INV		BIT(29)
 
+#define SDHCI_SPRD_REG_32_DLL_STS0	0x210
+#define SDHCI_SPRD_DLL_LOCKED		BIT(18)
+
 #define SDHCI_SPRD_REG_32_BUSY_POSI		0x250
 #define  SDHCI_SPRD_BIT_OUTR_CLK_AUTO_EN	BIT(25)
 #define  SDHCI_SPRD_BIT_INNR_CLK_AUTO_EN	BIT(24)
@@ -236,7 +239,7 @@ static inline void _sdhci_sprd_set_clock(struct sdhci_host *host,
 
 static void sdhci_sprd_enable_phy_dll(struct sdhci_host *host)
 {
-	u32 tmp;
+	u32 tmp, timeout = 1000;
 
 	tmp = sdhci_readl(host, SDHCI_SPRD_REG_32_DLL_CFG);
 	tmp &= ~(SDHCI_SPRD_DLL_EN | SDHCI_SPRD_DLL_ALL_CPST_EN);
@@ -256,6 +259,21 @@ static void sdhci_sprd_enable_phy_dll(struct sdhci_host *host)
 	sdhci_writel(host, tmp, SDHCI_SPRD_REG_32_DLL_CFG);
 	/* wait 1ms */
 	usleep_range(1000, 1250);
+
+	while (--timeout) {
+		if ((sdhci_readl(host, SDHCI_SPRD_REG_32_DLL_STS0) &
+		     SDHCI_SPRD_DLL_LOCKED))
+			break;
+		usleep_range(1000, 1250);
+	}
+
+	if (!timeout) {
+		pr_err("%s: DLL locked fail!\n", mmc_hostname(host->mmc));
+		pr_info("%s: DLL_STS0 : 0x%x, DLL_CFG : 0x%x\n",
+			 mmc_hostname(host->mmc),
+			 sdhci_readl(host, SDHCI_SPRD_REG_32_DLL_STS0),
+			 sdhci_readl(host, SDHCI_SPRD_REG_32_DLL_CFG));
+	}
 }
 
 static void sdhci_sprd_set_clock(struct sdhci_host *host, unsigned int clock)
-- 
2.25.1