rockchip: sdhci: Add HS400 Enhanced Strobe support for RK3568

On RK3568, a register bit must be set to enable Enhanced Strobe.
However, it appears that the address of this register may differ from
vendor to vendor and should be read from the underlying MMC IP. Let the
Rockchip SDHCI driver read this address and set the relevant bit when
Enhanced Strobe configuration is requested.

The IP uses a custom mode select value (0x7) for HS400, use that instead
of the common but non-standard SDHCI_CTRL_HS400 value (0x5). Also add
some necessary DLL_STRBIN and DLL_TXCLK configuration for HS400.

Additionally, a bit signifying that the connected hardware is an eMMC
chip must be set to enable Data Strobe for HS400 and HS400ES modes. Also
make the driver set this bit as appropriate.

This is partly ported from Linux's Synopsys DWC MSHC driver which
happens to be the underlying IP. (drivers/mmc/host/sdhci-of-dwcmshc.c in
Linux tree).

Co-developed-by: Yifeng Zhao <yifeng.zhao@rock-chips.com>
Signed-off-by: Yifeng Zhao <yifeng.zhao@rock-chips.com>
Signed-off-by: Alper Nebi Yasak <alpernebiyasak@gmail.com>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>

diff --git a/drivers/mmc/rockchip_sdhci.c b/drivers/mmc/rockchip_sdhci.c
index f4d5a59036a22457ab9f25f68d4f6b998be1739f..f3f9d83ba36fe4cfbda46ae8bc35a43085a8b6aa 100644 (file)
--- a/drivers/mmc/rockchip_sdhci.c
+++ b/drivers/mmc/rockchip_sdhci.c
@@ -22,6 +22,8 @@
 #include <asm/arch-rockchip/clock.h>
 #include <asm/arch-rockchip/hardware.h>
 
+/* DWCMSHC specific Mode Select value */
+#define DWCMSHC_CTRL_HS400             0x7
 /* 400KHz is max freq for card ID etc. Use that as min */
 #define EMMC_MIN_FREQ  400000
 #define KHz    (1000)
@@ -45,6 +47,14 @@
 #define ARASAN_VENDOR_REGISTER         0x78
 #define ARASAN_VENDOR_ENHANCED_STROBE  BIT(0)
 
+/* DWC IP vendor area 1 pointer */
+#define DWCMSHC_P_VENDOR_AREA1         0xe8
+#define DWCMSHC_AREA1_MASK             GENMASK(11, 0)
+/* Offset inside the vendor area 1 */
+#define DWCMSHC_EMMC_CONTROL           0x2c
+#define DWCMSHC_CARD_IS_EMMC           BIT(0)
+#define DWCMSHC_ENHANCED_STROBE                BIT(8)
+
 /* Rockchip specific Registers */
 #define DWCMSHC_EMMC_DLL_CTRL          0x800
 #define DWCMSHC_EMMC_DLL_CTRL_RESET    BIT(1)
@@ -60,8 +70,14 @@
 #define DWCMSHC_EMMC_DLL_INC_VALUE     2
 #define DWCMSHC_EMMC_DLL_INC           8
 #define DWCMSHC_EMMC_DLL_DLYENA                BIT(27)
-#define DLL_TXCLK_TAPNUM_DEFAULT       0x10
-#define DLL_STRBIN_TAPNUM_DEFAULT      0x3
+#define DLL_TXCLK_TAPNUM_DEFAULT       0xA
+
+#define DLL_STRBIN_TAPNUM_DEFAULT      0x8
+#define DLL_STRBIN_TAPNUM_FROM_SW      BIT(24)
+#define DLL_STRBIN_DELAY_NUM_SEL       BIT(26)
+#define DLL_STRBIN_DELAY_NUM_OFFSET    16
+#define DLL_STRBIN_DELAY_NUM_DEFAULT   0x16
+
 #define DLL_TXCLK_TAPNUM_FROM_SW       BIT(24)
 #define DWCMSHC_EMMC_DLL_LOCKED                BIT(8)
 #define DWCMSHC_EMMC_DLL_TIMEOUT       BIT(9)
@@ -327,7 +343,8 @@ static int rk3568_sdhci_emmc_set_clock(struct sdhci_host *host, unsigned int clo
                sdhci_writel(host, extra, DWCMSHC_EMMC_DLL_TXCLK);
 
                extra = DWCMSHC_EMMC_DLL_DLYENA |
-                       DLL_STRBIN_TAPNUM_DEFAULT;
+                       DLL_STRBIN_TAPNUM_DEFAULT |
+                       DLL_STRBIN_TAPNUM_FROM_SW;
                sdhci_writel(host, extra, DWCMSHC_EMMC_DLL_STRBIN);
        } else {
                /* reset the clock phase when the frequency is lower than 100MHz */
@@ -335,7 +352,15 @@ static int rk3568_sdhci_emmc_set_clock(struct sdhci_host *host, unsigned int clo
                extra = DLL_RXCLK_NO_INVERTER << DWCMSHC_EMMC_DLL_RXCLK_SRCSEL;
                sdhci_writel(host, extra, DWCMSHC_EMMC_DLL_RXCLK);
                sdhci_writel(host, 0, DWCMSHC_EMMC_DLL_TXCLK);
-               sdhci_writel(host, 0, DWCMSHC_EMMC_DLL_STRBIN);
+               /*
+                * Before switching to hs400es mode, the driver will enable
+                * enhanced strobe first. PHY needs to configure the parameters
+                * of enhanced strobe first.
+                */
+               extra = DWCMSHC_EMMC_DLL_DLYENA |
+                       DLL_STRBIN_DELAY_NUM_SEL |
+                       DLL_STRBIN_DELAY_NUM_DEFAULT << DLL_STRBIN_DELAY_NUM_OFFSET;
+               sdhci_writel(host, extra, DWCMSHC_EMMC_DLL_STRBIN);
        }
 
        return 0;
@@ -346,11 +371,30 @@ static int rk3568_emmc_get_phy(struct udevice *dev)
        return 0;
 }
 
+static int rk3568_sdhci_set_enhanced_strobe(struct sdhci_host *host)
+{
+       struct mmc *mmc = host->mmc;
+       u32 vendor;
+       int reg;
+
+       reg = (sdhci_readl(host, DWCMSHC_P_VENDOR_AREA1) & DWCMSHC_AREA1_MASK)
+             + DWCMSHC_EMMC_CONTROL;
+
+       vendor = sdhci_readl(host, reg);
+       if (mmc->selected_mode == MMC_HS_400_ES)
+               vendor |= DWCMSHC_ENHANCED_STROBE;
+       else
+               vendor &= ~DWCMSHC_ENHANCED_STROBE;
+       sdhci_writel(host, vendor, reg);
+
+       return 0;
+}
+
 static int rk3568_sdhci_set_ios_post(struct sdhci_host *host)
 {
        struct mmc *mmc = host->mmc;
        uint clock = mmc->tran_speed;
-       u32 reg;
+       u32 reg, vendor_reg;
 
        if (!clock)
                clock = mmc->clock;
@@ -360,8 +404,15 @@ static int rk3568_sdhci_set_ios_post(struct sdhci_host *host)
        if (mmc->selected_mode == MMC_HS_400 || mmc->selected_mode == MMC_HS_400_ES) {
                reg = sdhci_readw(host, SDHCI_HOST_CONTROL2);
                reg &= ~SDHCI_CTRL_UHS_MASK;
-               reg |= SDHCI_CTRL_HS400;
+               reg |= DWCMSHC_CTRL_HS400;
                sdhci_writew(host, reg, SDHCI_HOST_CONTROL2);
+
+               vendor_reg = (sdhci_readl(host, DWCMSHC_P_VENDOR_AREA1) & DWCMSHC_AREA1_MASK)
+                            + DWCMSHC_EMMC_CONTROL;
+               /* set CARD_IS_EMMC bit to enable Data Strobe for HS400 */
+               reg = sdhci_readw(host, vendor_reg);
+               reg |= DWCMSHC_CARD_IS_EMMC;
+               sdhci_writew(host, reg, vendor_reg);
        } else {
                sdhci_set_uhs_timing(host);
        }
@@ -554,6 +605,7 @@ static const struct sdhci_data rk3568_data = {
        .get_phy = rk3568_emmc_get_phy,
        .emmc_phy_init = rk3568_emmc_phy_init,
        .set_ios_post = rk3568_sdhci_set_ios_post,
+       .set_enhanced_strobe = rk3568_sdhci_set_enhanced_strobe,
 };
 
 static const struct udevice_id sdhci_ids[] = {