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path: root/drivers/mmc/tegra_mmc.c
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Diffstat (limited to 'drivers/mmc/tegra_mmc.c')
-rw-r--r--drivers/mmc/tegra_mmc.c16
1 files changed, 16 insertions, 0 deletions
diff --git a/drivers/mmc/tegra_mmc.c b/drivers/mmc/tegra_mmc.c
index 0df74ef..6c6affb 100644
--- a/drivers/mmc/tegra_mmc.c
+++ b/drivers/mmc/tegra_mmc.c
@@ -513,6 +513,22 @@ static int tegra_mmc_init(struct mmc *mmc)
tegra_mmc_reset(priv, mmc);
+#if defined(CONFIG_TEGRA124_MMC_DISABLE_EXT_LOOPBACK)
+ /*
+ * Disable the external clock loopback and use the internal one on
+ * SDMMC3 as per the SDMMC_VENDOR_MISC_CNTRL_0 register's SDMMC_SPARE1
+ * bits being set to 0xfffd according to the TRM.
+ *
+ * TODO(marcel.ziswiler@toradex.com): Move to device tree controlled
+ * approach once proper kernel integration made it mainline.
+ */
+ if (priv->reg == (void *)0x700b0400) {
+ mask = readl(&priv->reg->venmiscctl);
+ mask &= ~TEGRA_MMC_MISCON_ENABLE_EXT_LOOPBACK;
+ writel(mask, &priv->reg->venmiscctl);
+ }
+#endif
+
priv->version = readw(&priv->reg->hcver);
debug("host version = %x\n", priv->version);