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Subject[PATCH v2 3/8] mmc: tegra: Implement HS400 enhanced strobe
Date
Implement eMMC HS400 enhanced strobe. Enhanced strobe is an alternative
mechanism to the HS400 tuning procedure.

Signed-off-by: Aapo Vienamo <avienamo@nvidia.com>
---
drivers/mmc/host/sdhci-tegra.c | 23 +++++++++++++++++++++++
1 file changed, 23 insertions(+)

diff --git a/drivers/mmc/host/sdhci-tegra.c b/drivers/mmc/host/sdhci-tegra.c
index 6ec92bc..c0bb0f0 100644
--- a/drivers/mmc/host/sdhci-tegra.c
+++ b/drivers/mmc/host/sdhci-tegra.c
@@ -43,6 +43,9 @@
#define SDHCI_CLOCK_CTRL_PADPIPE_CLKEN_OVERRIDE BIT(3)
#define SDHCI_CLOCK_CTRL_SPI_MODE_CLKEN_OVERRIDE BIT(2)

+#define SDHCI_TEGRA_VENDOR_SYS_SW_CTRL 0x104
+#define SDHCI_TEGRA_SYS_SW_CTRL_ENHANCED_STROBE BIT(31)
+
#define SDHCI_TEGRA_VENDOR_CAP_OVERRIDES 0x10c
#define SDHCI_TEGRA_CAP_OVERRIDES_DQS_TRIM_MASK 0x00003f00
#define SDHCI_TEGRA_CAP_OVERRIDES_DQS_TRIM_SHIFT 8
@@ -272,6 +275,23 @@ static void tegra_sdhci_set_tap(struct sdhci_host *host, unsigned int tap)
}
}

+static void tegra_sdhci_hs400_enhanced_strobe(struct mmc_host *mmc,
+ struct mmc_ios *ios)
+{
+ struct sdhci_host *host = mmc_priv(mmc);
+ u32 val;
+
+ val = sdhci_readl(host, SDHCI_TEGRA_VENDOR_SYS_SW_CTRL);
+
+ if (ios->enhanced_strobe)
+ val |= SDHCI_TEGRA_SYS_SW_CTRL_ENHANCED_STROBE;
+ else
+ val &= ~SDHCI_TEGRA_SYS_SW_CTRL_ENHANCED_STROBE;
+
+ sdhci_writel(host, val, SDHCI_TEGRA_VENDOR_SYS_SW_CTRL);
+
+}
+
static void tegra_sdhci_reset(struct sdhci_host *host, u8 mask)
{
struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
@@ -950,6 +970,9 @@ static int sdhci_tegra_probe(struct platform_device *pdev)
sdhci_tegra_start_signal_voltage_switch;
}

+ host->mmc_host_ops.hs400_enhanced_strobe =
+ tegra_sdhci_hs400_enhanced_strobe;
+
rc = mmc_of_parse(host->mmc);
if (rc)
goto err_parse_dt;
--
2.7.4
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