mmc: sunxi: Support new mode

Almost all of the newer Allwinner SoCs have a new operating mode for the
eMMC clocks that needs to be enabled in both the clock and the MMC
controller.

Details about that mode are sparse, and the name itself (new mode vs old
mode) doesn't give much details, but it seems that the it changes the
sampling of the MMC clock. One side effect is also that it divides the
parent clock rate by 2.

Add support for it through a Kconfig option.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Reviewed-by: Jagan Teki <jagan@openedev.com>

arch/arm/include/asm/arch-sunxi/clock_sun8i_a83t.h

@@ -220,6 +220,7 @@ struct sunxi_ccm_reg {
 #define CCM_MMC_CTRL_SCLK_DLY(x)	((x) << 20)
 #define CCM_MMC_CTRL_OSCM24		(0x0 << 24)
 #define CCM_MMC_CTRL_PLL6		(0x1 << 24)
+#define CCM_MMC_CTRL_MODE_SEL_NEW	(0x1 << 30)
 #define CCM_MMC_CTRL_ENABLE		(0x1 << 31)
 
 #define CCM_USB_CTRL_PHY0_RST (0x1 << 0)

arch/arm/include/asm/arch-sunxi/mmc.h

@@ -35,16 +35,19 @@ struct sunxi_mmc {
 	u32 cbcr;		/* 0x48 CIU byte count */
 	u32 bbcr;		/* 0x4c BIU byte count */
 	u32 dbgc;		/* 0x50 debug enable */
-	u32 res0[11];
+	u32 res0;		/* 0x54 reserved */
+	u32 a12a;		/* 0x58 Auto command 12 argument */
+	u32 ntsr;		/* 0x5c	New timing set register */
+	u32 res1[8];
 	u32 dmac;		/* 0x80 internal DMA control */
 	u32 dlba;		/* 0x84 internal DMA descr list base address */
 	u32 idst;		/* 0x88 internal DMA status */
 	u32 idie;		/* 0x8c internal DMA interrupt enable */
 	u32 chda;		/* 0x90 */
 	u32 cbda;		/* 0x94 */
-	u32 res1[26];
+	u32 res2[26];
 #ifdef CONFIG_SUNXI_GEN_SUN6I
-	u32 res2[64];
+	u32 res3[64];
 #endif
 	u32 fifo;		/* 0x100 / 0x200 FIFO access address */
 };
@@ -116,6 +119,8 @@ struct sunxi_mmc {
 #define SUNXI_MMC_STATUS_CARD_DATA_BUSY		(0x1 << 9)
 #define SUNXI_MMC_STATUS_DATA_FSM_BUSY		(0x1 << 10)
 
+#define SUNXI_MMC_NTSR_MODE_SEL_NEW		(0x1 << 31)
+
 #define SUNXI_MMC_IDMAC_RESET		(0x1 << 0)
 #define SUNXI_MMC_IDMAC_FIXBURST	(0x1 << 1)
 #define SUNXI_MMC_IDMAC_ENABLE		(0x1 << 7)

drivers/mmc/Kconfig

@@ -369,6 +369,10 @@ config MMC_SUNXI
 	  This selects support for the SD/MMC Host Controller on
 	  Allwinner sunxi SoCs.
 
+config MMC_SUNXI_HAS_NEW_MODE
+	bool
+	depends on MMC_SUNXI
+
 config GENERIC_ATMEL_MCI
 	bool "Atmel Multimedia Card Interface support"
 	depends on DM_MMC && BLK && ARCH_AT91

drivers/mmc/sunxi_mmc.c

@@ -96,6 +96,18 @@ static int mmc_resource_init(int sdc_no)
 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;
+	u32 val = 0;
+
+	if (IS_ENABLED(CONFIG_MMC_SUNXI_HAS_NEW_MODE) && (priv->mmc_no == 2))
+		new_mode = true;
+
+	/*
+	 * The MMC clock has an extra /2 post-divider when operating in the new
+	 * mode.
+	 */
+	if (new_mode)
+		hz = hz * 2;
 
 	if (hz <= 24000000) {
 		pll = CCM_MMC_CTRL_OSCM24;
@@ -152,9 +164,18 @@ static int mmc_set_mod_clk(struct sunxi_mmc_priv *priv, unsigned int hz)
 #endif
 	}
 
-	writel(CCM_MMC_CTRL_ENABLE | pll | CCM_MMC_CTRL_SCLK_DLY(sclk_dly) |
-	       CCM_MMC_CTRL_N(n) | CCM_MMC_CTRL_OCLK_DLY(oclk_dly) |
-	       CCM_MMC_CTRL_M(div), priv->mclkreg);
+	if (new_mode) {
+#ifdef CONFIG_MMC_SUNXI_HAS_NEW_MODE
+		val = CCM_MMC_CTRL_MODE_SEL_NEW;
+		writel(SUNXI_MMC_NTSR_MODE_SEL_NEW, &priv->reg->ntsr);
+#endif
+	} else {
+		val = CCM_MMC_CTRL_OCLK_DLY(oclk_dly) |
+			CCM_MMC_CTRL_SCLK_DLY(sclk_dly);
+	}
+
+	writel(CCM_MMC_CTRL_ENABLE| pll | CCM_MMC_CTRL_N(n) |
+	       CCM_MMC_CTRL_M(div) | val, priv->mclkreg);
 
 	debug("mmc %u set mod-clk req %u parent %u n %u m %u rate %u\n",
 	      priv->mmc_no, hz, pll_hz, 1u << n, div, pll_hz / (1u << n) / div);