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From:   Aapo Vienamo <avienamo@nvidia.com>
To:     Ulf Hansson <ulf.hansson@linaro.org>,
        Rob Herring <robh+dt@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Thierry Reding <thierry.reding@gmail.com>,
        Jonathan Hunter <jonathanh@nvidia.com>,
        Adrian Hunter <adrian.hunter@intel.com>,
        Mikko Perttunen <mperttunen@nvidia.com>
CC:     <linux-mmc@vger.kernel.org>, <devicetree@vger.kernel.org>,
        <linux-tegra@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        Aapo Vienamo <avienamo@nvidia.com>
Subject: [PATCH 01/10] mmc: tegra: Poll for calibration completion
Date:   Tue, 24 Jul 2018 17:29:42 +0300
Message-ID: <1532442591-5640-2-git-send-email-avienamo@nvidia.com>
In-Reply-To: <1532442591-5640-1-git-send-email-avienamo@nvidia.com>
References: <1532442591-5640-1-git-send-email-avienamo@nvidia.com>
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Sender: linux-kernel-owner@vger.kernel.org
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Implement polling with 10 ms timeout for automatic pad drive strength
calibration.

Signed-off-by: Aapo Vienamo <avienamo@nvidia.com>
---
 drivers/mmc/host/sdhci-tegra.c | 24 +++++++++++++++++++-----
 1 file changed, 19 insertions(+), 5 deletions(-)

diff --git a/drivers/mmc/host/sdhci-tegra.c b/drivers/mmc/host/sdhci-tegra.c
index f108c48..e40ca43 100644
--- a/drivers/mmc/host/sdhci-tegra.c
+++ b/drivers/mmc/host/sdhci-tegra.c
@@ -49,6 +49,9 @@
 #define SDHCI_AUTO_CAL_START			BIT(31)
 #define SDHCI_AUTO_CAL_ENABLE			BIT(29)
 
+#define SDHCI_TEGRA_AUTO_CAL_STATUS     0x1ec
+#define SDHCI_TEGRA_AUTO_CAL_ACTIVE     BIT(31)
+
 #define NVQUIRK_FORCE_SDHCI_SPEC_200	BIT(0)
 #define NVQUIRK_ENABLE_BLOCK_GAP_DET	BIT(1)
 #define NVQUIRK_ENABLE_SDHCI_SPEC_300	BIT(2)
@@ -198,13 +201,24 @@ static void tegra_sdhci_reset(struct sdhci_host *host, u8 mask)
 
 static void tegra_sdhci_pad_autocalib(struct sdhci_host *host)
 {
-	u32 val;
+	unsigned timeout = 10;
+	u32 reg;
 
-	mdelay(1);
+	reg = sdhci_readl(host, SDHCI_TEGRA_AUTO_CAL_CONFIG);
+	reg |= SDHCI_AUTO_CAL_ENABLE | SDHCI_AUTO_CAL_START;
+	sdhci_writel(host, reg, SDHCI_TEGRA_AUTO_CAL_CONFIG);
+	udelay(1);
+
+	do {
+		reg = sdhci_readl(host, SDHCI_TEGRA_AUTO_CAL_STATUS);
+		if (!(reg & SDHCI_TEGRA_AUTO_CAL_ACTIVE))
+			break;
+		mdelay(1);
+		timeout--;
+	} while (timeout);
 
-	val = sdhci_readl(host, SDHCI_TEGRA_AUTO_CAL_CONFIG);
-	val |= SDHCI_AUTO_CAL_ENABLE | SDHCI_AUTO_CAL_START;
-	sdhci_writel(host,val, SDHCI_TEGRA_AUTO_CAL_CONFIG);
+	if (timeout == 0)
+		dev_err(mmc_dev(host->mmc), "Pad autocal timed out\n");
 }
 
 static void tegra_sdhci_set_clock(struct sdhci_host *host, unsigned int clock)
-- 
2.7.4