[U-Boot] [PATCH v2 1/5] mmc: sunxi: A64: add support for automatic delay calibration

Vasily Khoruzhick
2018-10-17T05:09:28Z

A64 supports automatic delay calibration and Linux driver uses it
instead of hardcoded delays. Add support for it to u-boot driver.

Fixes eMMC instability on Pinebook

Signed-off-by: Vasily Khoruzhick <anarsoul@gmail.com>
---
arch/arm/include/asm/arch-sunxi/mmc.h | 6 +++++-
drivers/mmc/sunxi_mmc.c | 21 ++++++++++++++++++++-
2 files changed, 25 insertions(+), 2 deletions(-)

diff --git a/arch/arm/include/asm/arch-sunxi/mmc.h b/arch/arm/include/asm/arch-sunxi/mmc.h
index d98c53faaa..f2deafddd2 100644
--- a/arch/arm/include/asm/arch-sunxi/mmc.h
+++ b/arch/arm/include/asm/arch-sunxi/mmc.h
@@ -46,7 +46,9 @@ struct sunxi_mmc {
u32 cbda; /* 0x94 */
u32 res2[26];
#if defined(CONFIG_SUNXI_GEN_SUN6I) || defined(CONFIG_MACH_SUN50I_H6)
- u32 res3[64];
+ u32 res3[17];
+ u32 samp_dl;
+ u32 res4[46];
#endif
u32 fifo; /* 0x100 / 0x200 FIFO access address */
};
@@ -130,5 +132,7 @@ struct sunxi_mmc {
#define SUNXI_MMC_COMMON_CLK_GATE (1 << 16)
#define SUNXI_MMC_COMMON_RESET (1 << 18)

+#define SUNXI_MMC_CAL_DL_SW_EN (0x1 << 7)
+
struct mmc *sunxi_mmc_init(int sdc_no);
#endif /* _SUNXI_MMC_H */
diff --git a/drivers/mmc/sunxi_mmc.c b/drivers/mmc/sunxi_mmc.c
index 39f15eb423..9e08ad59c6 100644
--- a/drivers/mmc/sunxi_mmc.c
+++ b/drivers/mmc/sunxi_mmc.c
@@ -99,11 +99,16 @@ static int mmc_set_mod_clk(struct sunxi_mmc_priv *priv, unsigned int hz)
{
unsigned int pll, pll_hz, div, n, oclk_dly, sclk_dly;
bool new_mode = false;
+ bool calibrate = false;
u32 val = 0;

if (IS_ENABLED(CONFIG_MMC_SUNXI_HAS_NEW_MODE) && (priv->mmc_no == 2))
new_mode = true;

+#ifdef CONFIG_MACH_SUN50I
+ calibrate = true;
+#endif
+
/*
* The MMC clock has an extra /2 post-divider when operating in the new
* mode.
@@ -174,7 +179,11 @@ static int mmc_set_mod_clk(struct sunxi_mmc_priv *priv, unsigned int hz)
val = CCM_MMC_CTRL_MODE_SEL_NEW;
setbits_le32(&priv->reg->ntsr, SUNXI_MMC_NTSR_MODE_SEL_NEW);
#endif
- } else {
+ } else if (!calibrate) {
+ /*
+ * Use hardcoded delay values if controller doesn't support
+ * calibration
+ */
val = CCM_MMC_CTRL_OCLK_DLY(oclk_dly) |
CCM_MMC_CTRL_SCLK_DLY(sclk_dly);
}
@@ -228,6 +237,16 @@ static int mmc_config_clock(struct sunxi_mmc_priv *priv, struct mmc *mmc)
rval &= ~SUNXI_MMC_CLK_DIVIDER_MASK;
writel(rval, &priv->reg->clkcr);

+#ifdef CONFIG_MACH_SUN50I
+ /* A64 supports calibration of delays on MMC controller and we
+ * have to set delay of zero before starting calibration.
+ * Allwinner BSP driver sets a delay only in the case of
+ * using HS400 which is not supported by mainline U-Boot or
+ * Linux at the moment
+ */
+ writel(SUNXI_MMC_CAL_DL_SW_EN, &priv->reg->samp_dl);
+#endif
+
/* Re-enable Clock */
rval |= SUNXI_MMC_CLK_ENABLE;
writel(rval, &priv->reg->clkcr);
--
2.19.0