[PATCH v2 3/7] mmc: sdhci-of-k1: add SDR tuning infrastructure

[Iker Pedrosa <ikerpedrosam@gmail.com>]

Add register definitions and delay line control functions to prepare for
SDR50/SDR104 tuning support:

- Add tuning register definitions (RX_CFG, DLINE_CTRL, DLINE_CFG)
- Add delay line control helper functions
- Add tuning preparation function

This infrastructure prepares for implementing the SDR tuning algorithm
while maintaining all existing functionality.

Signed-off-by: Iker Pedrosa <ikerpedrosam@gmail.com>
---
 drivers/mmc/host/sdhci-of-k1.c | 61 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 61 insertions(+)

diff --git a/drivers/mmc/host/sdhci-of-k1.c b/drivers/mmc/host/sdhci-of-k1.c
index 8af117a8e271c04a80d8dc7bb5ce12075652dd7a..79cb7c8d0b6d9c4206bf01721651c8efe8a173c9 100644
--- a/drivers/mmc/host/sdhci-of-k1.c
+++ b/drivers/mmc/host/sdhci-of-k1.c
@@ -68,6 +68,23 @@
 #define  SDHC_PHY_DRIVE_SEL		GENMASK(2, 0)
 #define  SDHC_RX_BIAS_CTRL		BIT(5)
 
+#define SPACEMIT_SDHC_RX_CFG_REG        0x118
+#define  SDHC_RX_SDCLK_SEL0_MASK        GENMASK(1, 0)
+#define  SDHC_RX_SDCLK_SEL1_MASK        GENMASK(3, 2)
+#define  SDHC_RX_SDCLK_SEL1             FIELD_PREP(SDHC_RX_SDCLK_SEL1_MASK, 1)
+
+#define SPACEMIT_SDHC_DLINE_CTRL_REG    0x130
+#define  SDHC_DLINE_PU                  BIT(0)
+#define  SDHC_RX_DLINE_CODE_MASK        GENMASK(23, 16)
+#define  SDHC_TX_DLINE_CODE_MASK        GENMASK(31, 24)
+
+#define SPACEMIT_SDHC_DLINE_CFG_REG     0x134
+#define  SDHC_RX_DLINE_REG_MASK         GENMASK(7, 0)
+#define  SDHC_RX_DLINE_GAIN             BIT(8)
+#define  SDHC_TX_DLINE_REG_MASK         GENMASK(23, 16)
+
+#define SPACEMIT_RX_DLINE_REG		9
+
 struct spacemit_sdhci_host {
 	struct clk *clk_core;
 	struct clk *clk_io;
@@ -95,6 +112,50 @@ static inline void spacemit_sdhci_clrsetbits(struct sdhci_host *host, u32 clr, u
 	sdhci_writel(host, val, reg);
 }
 
+static void spacemit_sdhci_set_rx_delay(struct sdhci_host *host, u8 delay)
+{
+	spacemit_sdhci_clrsetbits(host, SDHC_RX_DLINE_CODE_MASK,
+				  FIELD_PREP(SDHC_RX_DLINE_CODE_MASK, delay),
+				  SPACEMIT_SDHC_DLINE_CTRL_REG);
+}
+
+static void spacemit_sdhci_set_tx_delay(struct sdhci_host *host, u8 delay)
+{
+	spacemit_sdhci_clrsetbits(host, SDHC_TX_DLINE_CODE_MASK,
+				  FIELD_PREP(SDHC_TX_DLINE_CODE_MASK, delay),
+				  SPACEMIT_SDHC_DLINE_CTRL_REG);
+}
+
+static void spacemit_sdhci_set_tx_dline_reg(struct sdhci_host *host, u8 dline_reg)
+{
+	spacemit_sdhci_clrsetbits(host, SDHC_TX_DLINE_REG_MASK,
+				  FIELD_PREP(SDHC_TX_DLINE_REG_MASK, dline_reg),
+				  SPACEMIT_SDHC_DLINE_CFG_REG);
+}
+
+static void spacemit_sdhci_tx_tuning_prepare(struct sdhci_host *host)
+{
+	spacemit_sdhci_setbits(host, SDHC_TX_MUX_SEL, SPACEMIT_SDHC_TX_CFG_REG);
+	spacemit_sdhci_setbits(host, SDHC_DLINE_PU, SPACEMIT_SDHC_DLINE_CTRL_REG);
+	udelay(5);
+}
+
+static void spacemit_sdhci_prepare_tuning(struct sdhci_host *host)
+{
+	spacemit_sdhci_clrsetbits(host, SDHC_RX_DLINE_REG_MASK,
+				  FIELD_PREP(SDHC_RX_DLINE_REG_MASK, SPACEMIT_RX_DLINE_REG),
+				  SPACEMIT_SDHC_DLINE_CFG_REG);
+
+	spacemit_sdhci_setbits(host, SDHC_DLINE_PU, SPACEMIT_SDHC_DLINE_CTRL_REG);
+	udelay(5);
+
+	spacemit_sdhci_clrsetbits(host, SDHC_RX_SDCLK_SEL1_MASK, SDHC_RX_SDCLK_SEL1,
+				  SPACEMIT_SDHC_RX_CFG_REG);
+
+	if (host->mmc->ios.timing == MMC_TIMING_MMC_HS200)
+		spacemit_sdhci_setbits(host, SDHC_HS200_USE_RFIFO, SPACEMIT_SDHC_PHY_FUNC_REG);
+}
+
 static void spacemit_sdhci_reset(struct sdhci_host *host, u8 mask)
 {
 	sdhci_reset(host, mask);

-- 
2.53.0