[PATCH 3/3] mmc: sdhci-of-arasan: Add support for ZynqMP Platform Tap Delays Setup

[Manish Narani]

Apart from taps set by auto tuning, ZynqMP platform has feature to set
the tap values manually. Add support to read tap delay values from
DT and set the same in HW via ZynqMP SoC framework. Reading Tap
Delays from DT is optional, if the property is not available in DT the
driver will use the pre-defined Tap Delay Values.

Signed-off-by: Manish Narani <manish.narani@xxxxxxxxxx>
---
 drivers/mmc/host/sdhci-of-arasan.c | 173 ++++++++++++++++++++++++++++++++++++-
 1 file changed, 172 insertions(+), 1 deletion(-)

diff --git a/drivers/mmc/host/sdhci-of-arasan.c b/drivers/mmc/host/sdhci-of-arasan.c
index b12abf9..7af6cec 100644
--- a/drivers/mmc/host/sdhci-of-arasan.c
+++ b/drivers/mmc/host/sdhci-of-arasan.c
@@ -22,6 +22,7 @@
 #include <linux/phy/phy.h>
 #include <linux/regmap.h>
 #include <linux/of.h>
+#include <linux/firmware/xlnx-zynqmp.h>
 
 #include "cqhci.h"
 #include "sdhci-pltfm.h"
@@ -32,6 +33,10 @@
 
 #define PHY_CLK_TOO_SLOW_HZ		400000
 
+/* Default settings for ZynqMP Tap Delays */
+#define ZYNQMP_ITAP_DELAYS {0, 0x15, 0x15, 0, 0x15, 0, 0, 0x3D, 0x12, 0, 0}
+#define ZYNQMP_OTAP_DELAYS {0, 0x5, 0x6, 0, 0x5, 0x3, 0x3, 0x4, 0x6, 0x3, 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
@@ -81,6 +86,7 @@ struct sdhci_arasan_soc_ctl_map {
  * @sdcardclk:		Pointer to normal 'struct clock' for sdcardclk_hw.
  * @soc_ctl_base:	Pointer to regmap for syscon for soc_ctl registers.
  * @soc_ctl_map:	Map to get offsets into soc_ctl registers.
+ * @of_data:		Platform specific runtime data storage pointer
  */
 struct sdhci_arasan_data {
 	struct sdhci_host *host;
@@ -101,6 +107,15 @@ struct sdhci_arasan_data {
 /* Controller immediately reports SDHCI_CLOCK_INT_STABLE after enabling the
  * internal clock even when the clock isn't stable */
 #define SDHCI_ARASAN_QUIRK_CLOCK_UNSTABLE BIT(1)
+
+	void *of_data;
+};
+
+struct sdhci_arasan_zynqmp_data {
+	void (*set_tap_delay)(struct sdhci_host *host);
+	const struct zynqmp_eemi_ops *eemi_ops;
+	u8 tapdly[MMC_TIMING_MMC_HS400 + 1][2]; /* [0] for input delay, */
+						/* [1] for output delay */
 };
 
 struct sdhci_arasan_of_data {
@@ -209,6 +224,16 @@ static void sdhci_arasan_set_clock(struct sdhci_host *host, unsigned int clock)
 		sdhci_arasan->is_phy_on = false;
 	}
 
+	/* Set the Input and Output Tap Delays */
+	if (host->version >= SDHCI_SPEC_300 &&
+	    host->timing != MMC_TIMING_LEGACY &&
+	    host->timing != MMC_TIMING_UHS_SDR12) {
+		struct sdhci_arasan_zynqmp_data *zynqmp_data =
+			sdhci_arasan->of_data;
+		if (zynqmp_data && zynqmp_data->set_tap_delay)
+			zynqmp_data->set_tap_delay(host);
+	}
+
 	sdhci_set_clock(host, clock);
 
 	if (sdhci_arasan->quirks & SDHCI_ARASAN_QUIRK_CLOCK_UNSTABLE)
@@ -487,6 +512,10 @@ static const struct of_device_id sdhci_arasan_of_match[] = {
 		.compatible = "arasan,sdhci-4.9a",
 		.data = &sdhci_arasan_data,
 	},
+	{
+		.compatible = "xlnx,zynqmp-8.9a",
+		.data = &sdhci_arasan_data,
+	},
 	{ /* sentinel */ }
 };
 MODULE_DEVICE_TABLE(of, sdhci_arasan_of_match);
@@ -517,6 +546,37 @@ static const struct clk_ops arasan_sdcardclk_ops = {
 };
 
 /**
+ * sdhci_zynqmp_sdcardclk_set_phase - Set the SD Clock Tap Delays
+ *
+ * Set the SD Clock Tap Delays for Input and Output paths
+ *
+ * @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_zynqmp_sdcardclk_set_phase(struct clk_hw *hw, int degrees)
+
+{
+	struct sdhci_arasan_data *sdhci_arasan =
+		container_of(hw, struct sdhci_arasan_data, sdcardclk_hw);
+	struct sdhci_arasan_zynqmp_data *zynqmp_data = sdhci_arasan->of_data;
+	const struct zynqmp_eemi_ops *eemi_ops = zynqmp_data->eemi_ops;
+	const char *clk_name = clk_hw_get_name(hw);
+	u32 device_id = !strcmp(clk_name, "clk_sd0") ? 0 : 1;
+
+	if (!eemi_ops->sdio_setphase)
+		return -ENODEV;
+
+	/* Set the Clock Phase */
+	return eemi_ops->sdio_setphase(device_id, degrees);
+}
+
+static const struct clk_ops zynqmp_sdcardclk_ops = {
+	.recalc_rate = sdhci_arasan_sdcardclk_recalc_rate,
+	.set_phase = sdhci_zynqmp_sdcardclk_set_phase,
+};
+
+/**
  * sdhci_arasan_update_clockmultiplier - Set corecfg_clockmultiplier
  *
  * The corecfg_clockmultiplier is supposed to contain clock multiplier
@@ -638,7 +698,10 @@ static int sdhci_arasan_register_sdclk(struct sdhci_arasan_data *sdhci_arasan,
 	sdcardclk_init.parent_names = &parent_clk_name;
 	sdcardclk_init.num_parents = 1;
 	sdcardclk_init.flags = CLK_GET_RATE_NOCACHE;
-	sdcardclk_init.ops = &arasan_sdcardclk_ops;
+	if (of_device_is_compatible(np, "xlnx,zynqmp-8.9a"))
+		sdcardclk_init.ops = &zynqmp_sdcardclk_ops;
+	else
+		sdcardclk_init.ops = &arasan_sdcardclk_ops;
 
 	sdhci_arasan->sdcardclk_hw.init = &sdcardclk_init;
 	sdhci_arasan->sdcardclk =
@@ -714,6 +777,108 @@ static int sdhci_arasan_add_host(struct sdhci_arasan_data *sdhci_arasan)
 	return ret;
 }
 
+static void sdhci_arasan_zynqmp_set_tap_delay(struct sdhci_host *host)
+{
+	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
+	struct sdhci_arasan_data *sdhci_arasan = sdhci_pltfm_priv(pltfm_host);
+	struct sdhci_arasan_zynqmp_data *zynqmp_data = sdhci_arasan->of_data;
+
+	clk_set_phase(sdhci_arasan->sdcardclk,
+		      (int)zynqmp_data->tapdly[host->timing][0]);
+	clk_set_phase(sdhci_arasan->sdcardclk,
+		      (int)zynqmp_data->tapdly[host->timing][1] +
+		      INPUT_TAP_BOUNDARY);
+}
+
+static void arasan_dt_read_tap_delay(struct device *dev, u8 *tapdly,
+				     const char *prop, u8 itap_def, u8 otap_def)
+{
+	struct device_node *np = dev->of_node;
+
+	tapdly[0] = itap_def;
+	tapdly[1] = otap_def;
+
+	/*
+	 * Read Tap Delay values from DT, if the DT does not contain the
+	 * Tap Values then use the pre-defined values.
+	 */
+	if (of_property_read_variable_u8_array(np, prop, &tapdly[0], 2, 0)) {
+		dev_dbg(dev, "Using predefined tapdly for %s = %d %d\n",
+			prop, tapdly[0], tapdly[1]);
+	}
+}
+
+/**
+ * arasan_dt_parse_tap_delays - Read Tap Delay values from DT
+ *
+ * Called at initialization to parse the values of Tap Delays.
+ *
+ * @dev:		Pointer to our struct device.
+ */
+static int arasan_dt_parse_tap_delays(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct sdhci_host *host = platform_get_drvdata(pdev);
+	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
+	struct sdhci_arasan_data *sdhci_arasan = sdhci_pltfm_priv(pltfm_host);
+	struct sdhci_arasan_zynqmp_data zynqmp_data;
+	const struct zynqmp_eemi_ops *eemi_ops;
+	u8 *itapdly, *otapdly;
+	u32 mio_bank = 0;
+
+	eemi_ops = zynqmp_pm_get_eemi_ops();
+	if (IS_ERR(eemi_ops))
+		return PTR_ERR(eemi_ops);
+
+	itapdly = (u8 [MMC_TIMING_MMC_HS400 + 1]) ZYNQMP_ITAP_DELAYS;
+	otapdly = (u8 [MMC_TIMING_MMC_HS400 + 1]) ZYNQMP_OTAP_DELAYS;
+
+	of_property_read_u32(pdev->dev.of_node, "xlnx,mio-bank", &mio_bank);
+	if (mio_bank == 2) {
+		otapdly[MMC_TIMING_UHS_SDR104] = 0x2;
+		otapdly[MMC_TIMING_MMC_HS200] = 0x2;
+	}
+
+	arasan_dt_read_tap_delay(dev, zynqmp_data.tapdly[MMC_TIMING_MMC_HS],
+				 "xlnx,tap-delay-mmc-hsd",
+				 itapdly[MMC_TIMING_MMC_HS],
+				 otapdly[MMC_TIMING_MMC_HS]);
+	arasan_dt_read_tap_delay(dev, zynqmp_data.tapdly[MMC_TIMING_SD_HS],
+				 "xlnx,tap-delay-sd-hsd",
+				 itapdly[MMC_TIMING_SD_HS],
+				 otapdly[MMC_TIMING_SD_HS]);
+	arasan_dt_read_tap_delay(dev, zynqmp_data.tapdly[MMC_TIMING_UHS_SDR25],
+				 "xlnx,tap-delay-sdr25",
+				 itapdly[MMC_TIMING_UHS_SDR25],
+				 otapdly[MMC_TIMING_UHS_SDR25]);
+	arasan_dt_read_tap_delay(dev, zynqmp_data.tapdly[MMC_TIMING_UHS_SDR50],
+				 "xlnx,tap-delay-sdr50",
+				 itapdly[MMC_TIMING_UHS_SDR50],
+				 otapdly[MMC_TIMING_UHS_SDR50]);
+	arasan_dt_read_tap_delay(dev, zynqmp_data.tapdly[MMC_TIMING_UHS_SDR104],
+				 "xlnx,tap-delay-sdr104",
+				 itapdly[MMC_TIMING_UHS_SDR104],
+				 otapdly[MMC_TIMING_UHS_SDR104]);
+	arasan_dt_read_tap_delay(dev, zynqmp_data.tapdly[MMC_TIMING_UHS_DDR50],
+				 "xlnx,tap-delay-sd-ddr50",
+				 itapdly[MMC_TIMING_UHS_DDR50],
+				 otapdly[MMC_TIMING_UHS_DDR50]);
+	arasan_dt_read_tap_delay(dev, zynqmp_data.tapdly[MMC_TIMING_MMC_DDR52],
+				 "xlnx,tap-delay-mmc-ddr52",
+				 itapdly[MMC_TIMING_MMC_DDR52],
+				 otapdly[MMC_TIMING_MMC_DDR52]);
+	arasan_dt_read_tap_delay(dev, zynqmp_data.tapdly[MMC_TIMING_MMC_HS200],
+				 "xlnx,tap-delay-mmc-hs200",
+				 itapdly[MMC_TIMING_MMC_HS200],
+				 otapdly[MMC_TIMING_MMC_HS200]);
+
+	zynqmp_data.set_tap_delay = sdhci_arasan_zynqmp_set_tap_delay;
+	zynqmp_data.eemi_ops = eemi_ops;
+	sdhci_arasan->of_data = &zynqmp_data;
+
+	return 0;
+}
+
 static int sdhci_arasan_probe(struct platform_device *pdev)
 {
 	int ret;
@@ -806,6 +971,12 @@ static int sdhci_arasan_probe(struct platform_device *pdev)
 		goto unreg_clk;
 	}
 
+	if (of_device_is_compatible(pdev->dev.of_node, "xlnx,zynqmp-8.9a")) {
+		ret = arasan_dt_parse_tap_delays(&pdev->dev);
+		if (ret)
+			goto unreg_clk;
+	}
+
 	sdhci_arasan->phy = ERR_PTR(-ENODEV);
 	if (of_device_is_compatible(pdev->dev.of_node,
 				    "arasan,sdhci-5.1")) {
-- 
2.1.1