[PATCH v2 2/4] sdhci: arasan: Add support for Versal Tap Delays

[Manish Narani]

Add support to set tap delays for Xilinx Versal SD controller. The tap
delay registers have moved to SD controller space in Versal. Make the
changes accordingly.

Signed-off-by: Manish Narani <manish.narani@xxxxxxxxxx>
---
 drivers/mmc/host/sdhci-of-arasan.c | 175 +++++++++++++++++++++++++++++
 1 file changed, 175 insertions(+)

diff --git a/drivers/mmc/host/sdhci-of-arasan.c b/drivers/mmc/host/sdhci-of-arasan.c
index 0146d7dd315b..34403b2cac97 100644
--- a/drivers/mmc/host/sdhci-of-arasan.c
+++ b/drivers/mmc/host/sdhci-of-arasan.c
@@ -28,15 +28,26 @@
 #include "sdhci-pltfm.h"
 
 #define SDHCI_ARASAN_VENDOR_REGISTER	0x78
+
+#define SDHCI_ARASAN_ITAPDLY_REGISTER	0xF0F8
+#define SDHCI_ARASAN_OTAPDLY_REGISTER	0xF0FC
+
 #define SDHCI_ARASAN_CQE_BASE_ADDR	0x200
 #define VENDOR_ENHANCED_STROBE		BIT(0)
 
 #define PHY_CLK_TOO_SLOW_HZ		400000
 
+#define SDHCI_ITAPDLY_CHGWIN		0x200
+#define SDHCI_ITAPDLY_ENABLE		0x100
+#define SDHCI_OTAPDLY_ENABLE		0x40
+
 /* Default settings for ZynqMP Clock Phases */
 #define ZYNQMP_ICLK_PHASE {0, 63, 63, 0, 63,  0,   0, 183, 54,  0, 0}
 #define ZYNQMP_OCLK_PHASE {0, 72, 60, 0, 60, 72, 135, 48, 72, 135, 0}
 
+#define VERSAL_ICLK_PHASE {0, 132, 132, 0, 132, 0, 0, 162, 90, 0, 0}
+#define VERSAL_OCLK_PHASE {0,  60, 48, 0, 48, 72, 90, 36, 60, 90, 0}
+
 /*
  * On some SoCs the syscon area has a feature where the upper 16-bits of
  * each 32-bit register act as a write mask for the lower 16-bits.  This allows
@@ -566,6 +577,10 @@ static const struct of_device_id sdhci_arasan_of_match[] = {
 		.compatible = "xlnx,zynqmp-8.9a",
 		.data = &sdhci_arasan_zynqmp_data,
 	},
+	{
+		.compatible = "xlnx,versal-8.9a",
+		.data = &sdhci_arasan_zynqmp_data,
+	},
 	{ /* sentinel */ }
 };
 MODULE_DEVICE_TABLE(of, sdhci_arasan_of_match);
@@ -768,6 +783,152 @@ static const struct clk_ops zynqmp_sampleclk_ops = {
 	.set_phase = sdhci_zynqmp_sampleclk_set_phase,
 };
 
+/**
+ * sdhci_versal_sdcardclk_set_phase - Set the SD Output Clock Tap Delays
+ *
+ * Set the SD Output Clock Tap Delays for Output path
+ *
+ * @hw:			Pointer to the hardware clock structure.
+ * @degrees		The clock phase shift between 0 - 359.
+ * Return: 0 on success and error value on error
+ */
+static int sdhci_versal_sdcardclk_set_phase(struct clk_hw *hw, int degrees)
+{
+	struct sdhci_arasan_clk_data *clk_data =
+		container_of(hw, struct sdhci_arasan_clk_data, sdcardclk_hw);
+	struct sdhci_arasan_data *sdhci_arasan =
+		container_of(clk_data, struct sdhci_arasan_data, clk_data);
+	struct sdhci_host *host = sdhci_arasan->host;
+	u8 tap_delay, tap_max = 0;
+	int ret;
+
+	/*
+	 * This is applicable for SDHCI_SPEC_300 and above
+	 * Versal does not set phase for <=25MHz clock.
+	 * If degrees is zero, no need to do anything.
+	 */
+	if (host->version < SDHCI_SPEC_300 ||
+	    host->timing == MMC_TIMING_LEGACY ||
+	    host->timing == MMC_TIMING_UHS_SDR12 || !degrees)
+		return 0;
+
+	switch (host->timing) {
+	case MMC_TIMING_MMC_HS:
+	case MMC_TIMING_SD_HS:
+	case MMC_TIMING_UHS_SDR25:
+	case MMC_TIMING_UHS_DDR50:
+	case MMC_TIMING_MMC_DDR52:
+		/* For 50MHz clock, 30 Taps are available */
+		tap_max = 30;
+		break;
+	case MMC_TIMING_UHS_SDR50:
+		/* For 100MHz clock, 15 Taps are available */
+		tap_max = 15;
+		break;
+	case MMC_TIMING_UHS_SDR104:
+	case MMC_TIMING_MMC_HS200:
+		/* For 200MHz clock, 8 Taps are available */
+		tap_max = 8;
+	default:
+		break;
+	}
+
+	tap_delay = (degrees * tap_max) / 360;
+
+	/* Set the Clock Phase */
+	if (tap_delay) {
+		u32 regval;
+
+		regval = sdhci_readl(host, SDHCI_ARASAN_OTAPDLY_REGISTER);
+		regval |= SDHCI_OTAPDLY_ENABLE;
+		sdhci_writel(host, regval, SDHCI_ARASAN_OTAPDLY_REGISTER);
+		regval |= tap_delay;
+		sdhci_writel(host, regval, SDHCI_ARASAN_OTAPDLY_REGISTER);
+	}
+
+	return ret;
+}
+
+static const struct clk_ops versal_sdcardclk_ops = {
+	.recalc_rate = sdhci_arasan_sdcardclk_recalc_rate,
+	.set_phase = sdhci_versal_sdcardclk_set_phase,
+};
+
+/**
+ * sdhci_versal_sampleclk_set_phase - Set the SD Input Clock Tap Delays
+ *
+ * Set the SD Input Clock Tap Delays for Input path
+ *
+ * @hw:			Pointer to the hardware clock structure.
+ * @degrees		The clock phase shift between 0 - 359.
+ * Return: 0 on success and error value on error
+ */
+static int sdhci_versal_sampleclk_set_phase(struct clk_hw *hw, int degrees)
+{
+	struct sdhci_arasan_clk_data *clk_data =
+		container_of(hw, struct sdhci_arasan_clk_data, sampleclk_hw);
+	struct sdhci_arasan_data *sdhci_arasan =
+		container_of(clk_data, struct sdhci_arasan_data, clk_data);
+	struct sdhci_host *host = sdhci_arasan->host;
+	u8 tap_delay, tap_max = 0;
+	int ret;
+
+	/*
+	 * This is applicable for SDHCI_SPEC_300 and above
+	 * Versal does not set phase for <=25MHz clock.
+	 * If degrees is zero, no need to do anything.
+	 */
+	if (host->version < SDHCI_SPEC_300 ||
+	    host->timing == MMC_TIMING_LEGACY ||
+	    host->timing == MMC_TIMING_UHS_SDR12 || !degrees)
+		return 0;
+
+	switch (host->timing) {
+	case MMC_TIMING_MMC_HS:
+	case MMC_TIMING_SD_HS:
+	case MMC_TIMING_UHS_SDR25:
+	case MMC_TIMING_UHS_DDR50:
+	case MMC_TIMING_MMC_DDR52:
+		/* For 50MHz clock, 120 Taps are available */
+		tap_max = 120;
+		break;
+	case MMC_TIMING_UHS_SDR50:
+		/* For 100MHz clock, 60 Taps are available */
+		tap_max = 60;
+		break;
+	case MMC_TIMING_UHS_SDR104:
+	case MMC_TIMING_MMC_HS200:
+		/* For 200MHz clock, 30 Taps are available */
+		tap_max = 30;
+	default:
+		break;
+	}
+
+	tap_delay = (degrees * tap_max) / 360;
+
+	/* Set the Clock Phase */
+	if (tap_delay) {
+		u32 regval;
+
+		regval = sdhci_readl(host, SDHCI_ARASAN_ITAPDLY_REGISTER);
+		regval |= SDHCI_ITAPDLY_CHGWIN;
+		sdhci_writel(host, regval, SDHCI_ARASAN_ITAPDLY_REGISTER);
+		regval |= SDHCI_ITAPDLY_ENABLE;
+		sdhci_writel(host, regval, SDHCI_ARASAN_ITAPDLY_REGISTER);
+		regval |= tap_delay;
+		sdhci_writel(host, regval, SDHCI_ARASAN_ITAPDLY_REGISTER);
+		regval &= ~SDHCI_ITAPDLY_CHGWIN;
+		sdhci_writel(host, regval, SDHCI_ARASAN_ITAPDLY_REGISTER);
+	}
+
+	return ret;
+}
+
+static const struct clk_ops versal_sampleclk_ops = {
+	.recalc_rate = sdhci_arasan_sampleclk_recalc_rate,
+	.set_phase = sdhci_versal_sampleclk_set_phase,
+};
+
 static void arasan_zynqmp_dll_reset(struct sdhci_host *host, u32 deviceid)
 {
 	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
@@ -965,6 +1126,16 @@ static void arasan_dt_parse_clk_phases(struct device *dev,
 		}
 	}
 
+	if (of_device_is_compatible(dev->of_node, "xlnx,versal-8.9a")) {
+		iclk_phase = (int [MMC_TIMING_MMC_HS400 + 1]) VERSAL_ICLK_PHASE;
+		oclk_phase = (int [MMC_TIMING_MMC_HS400 + 1]) VERSAL_OCLK_PHASE;
+
+		for (i = 0; i <= MMC_TIMING_MMC_HS400; i++) {
+			clk_data->clk_phase_in[i] = iclk_phase[i];
+			clk_data->clk_phase_out[i] = oclk_phase[i];
+		}
+	}
+
 	arasan_dt_read_clk_phase(dev, clk_data, MMC_TIMING_LEGACY,
 				 "clk-phase-legacy");
 	arasan_dt_read_clk_phase(dev, clk_data, MMC_TIMING_MMC_HS,
@@ -1025,6 +1196,8 @@ sdhci_arasan_register_sdcardclk(struct sdhci_arasan_data *sdhci_arasan,
 	sdcardclk_init.flags = CLK_GET_RATE_NOCACHE;
 	if (of_device_is_compatible(np, "xlnx,zynqmp-8.9a"))
 		sdcardclk_init.ops = &zynqmp_sdcardclk_ops;
+	else if (of_device_is_compatible(np, "xlnx,versal-8.9a"))
+		sdcardclk_init.ops = &versal_sdcardclk_ops;
 	else
 		sdcardclk_init.ops = &arasan_sdcardclk_ops;
 
@@ -1077,6 +1250,8 @@ sdhci_arasan_register_sampleclk(struct sdhci_arasan_data *sdhci_arasan,
 	sampleclk_init.flags = CLK_GET_RATE_NOCACHE;
 	if (of_device_is_compatible(np, "xlnx,zynqmp-8.9a"))
 		sampleclk_init.ops = &zynqmp_sampleclk_ops;
+	else if (of_device_is_compatible(np, "xlnx,versal-8.9a"))
+		sampleclk_init.ops = &versal_sampleclk_ops;
 	else
 		sampleclk_init.ops = &arasan_sampleclk_ops;
 
-- 
2.17.1