[PATCH v2 4/4] phy: exynos5-usbdrd: Calibrate LOS levels for exynos5420/5800

[Vivek Gautam]

Adding phy calibrate callback, which facilitates setting certain
PHY settings post initialization of the PHY controller.
Exynos5420 and Exynos5800 have 28nm USB 3.0 DRD PHY for which
the Loss-of-Signal (LOS) Detector Threshold Level as well as
Tx-Vboost-Level should be controlled for Super-Speed operations.

Additionally set proper time to wait for RxDetect measurement,
for desired PHY reference clock, so as to solve issue with enumeration
of few USB 3.0 devices, like Samsung SUM-TSB16S 3.0 USB drive
on the controller.
We are using CR_port for this purpose to send required data
to override the LOS values.

On testing with USB 3.0 devices on USB 3.0 port present on
SMDK5420, and peach-pit boards should see following message:
usb 2-1: new SuperSpeed USB device number 2 using xhci-hcd

and without this patch, should see below shown message:
usb 1-1: new high-speed USB device number 2 using xhci-hcd

Signed-off-by: Vivek Gautam <gautam.vivek@xxxxxxxxxxx>
---
 drivers/phy/phy-exynos5-usbdrd.c |  169 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 169 insertions(+)

diff --git a/drivers/phy/phy-exynos5-usbdrd.c b/drivers/phy/phy-exynos5-usbdrd.c
index 56285af..b214483 100644
--- a/drivers/phy/phy-exynos5-usbdrd.c
+++ b/drivers/phy/phy-exynos5-usbdrd.c
@@ -89,8 +89,20 @@
 #define PHYCLKRST_COMMONONN			BIT(0)
 
 #define EXYNOS5_DRD_PHYREG0			0x14
+
+#define EXYNOS5_DRD_PHYREG0_SSC_REF_CLK_SEL	BIT(21)
+#define EXYNOS5_DRD_PHYREG0_SSC_RANGE		BIT(20)
+#define EXYNOS5_DRD_PHYREG0_CR_WRITE		BIT(19)
+#define EXYNOS5_DRD_PHYREG0_CR_READ		BIT(18)
+#define EXYNOS5_DRD_PHYREG0_CR_DATA_IN(_x)	((_x) << 2)
+#define EXYNOS5_DRD_PHYREG0_CR_CAP_DATA		BIT(1)
+#define EXYNOS5_DRD_PHYREG0_CR_CAP_ADDR		BIT(0)
+
 #define EXYNOS5_DRD_PHYREG1			0x18
 
+#define EXYNOS5_DRD_PHYREG1_CR_DATA_OUT(_x)	((_x) << 1)
+#define EXYNOS5_DRD_PHYREG1_CR_ACK		BIT(0)
+
 #define EXYNOS5_DRD_PHYPARAM0			0x1c
 
 #define PHYPARAM0_REF_USE_PAD			BIT(31)
@@ -118,6 +130,26 @@
 #define EXYNOS5_DRD_PHYRESUME			0x34
 #define EXYNOS5_DRD_LINKPORT			0x44
 
+/* USB 3.0 DRD PHY SS Function Control Reg; accessed by CR_PORT */
+#define EXYNOS5_DRD_PHYSS_LOSLEVEL_OVRD_IN		(0x15)
+
+#define LOSLEVEL_OVRD_IN_LOS_BIAS_5420			(0x5 << 13)
+#define LOSLEVEL_OVRD_IN_LOS_BIAS_DEFAULT		(0x0 << 13)
+#define LOSLEVEL_OVRD_IN_EN				(0x1 << 10)
+#define LOSLEVEL_OVRD_IN_LOS_LEVEL_DEFAULT		(0x9 << 0)
+
+#define EXYNOS5_DRD_PHYSS_TX_VBOOSTLEVEL_OVRD_IN	(0x12)
+#define TX_VBOOSTLEVEL_OVRD_IN_VBOOST_5420		(0x5 << 13)
+#define TX_VBOOSTLEVEL_OVRD_IN_VBOOST_DEFAULT		(0x4 << 13)
+
+#define EXYNOS5_DRD_PHYSS_LANE0_TX_DEBUG		(0x1010)
+#define LANE0_TX_DEBUG_RXDET_MEAS_TIME_19M2_20M		(0x4 << 4)
+#define LANE0_TX_DEBUG_RXDET_MEAS_TIME_24M		(0x8 << 4)
+#define LANE0_TX_DEBUG_RXDET_MEAS_TIME_25M_26M		(0x8 << 4)
+#define LANE0_TX_DEBUG_RXDET_MEAS_TIME_48M_50M_52M	(0x20 << 4)
+#define LANE0_TX_DEBUG_RXDET_MEAS_TIME_62M5		(0x20 << 4)
+#define LANE0_TX_DEBUG_RXDET_MEAS_TIME_96M_100M		(0x40 << 4)
+
 #define KHZ	1000
 #define MHZ	(KHZ * KHZ)
 
@@ -135,12 +167,14 @@ struct exynos5_usbdrd_phy_config {
 	void (*phy_isol)(struct phy_usb_instance *inst, u32 on);
 	void (*phy_init)(struct exynos5_usbdrd_phy *phy_drd);
 	unsigned int (*set_refclk)(struct phy_usb_instance *inst);
+	int (*phy_calibrate)(struct phy_usb_instance *inst);
 };
 
 struct exynos5_usbdrd_phy_drvdata {
 	const struct exynos5_usbdrd_phy_config *phy_cfg;
 	u32 pmu_offset_usbdrd0_phy;
 	u32 pmu_offset_usbdrd1_phy;
+	void (*calibrate)(struct exynos5_usbdrd_phy *phy_drd);
 };
 
 /**
@@ -487,6 +521,138 @@ static int exynos5_usbdrd_phy_power_off(struct phy *phy)
 	return 0;
 }
 
+static void crport_handshake(struct exynos5_usbdrd_phy *phy_drd,
+						u32 val, u32 cmd)
+{
+	u32 usec = 100;
+	u32 result;
+
+	writel(val | cmd, phy_drd->reg_phy + EXYNOS5_DRD_PHYREG0);
+
+	do {
+		result = readl(phy_drd->reg_phy + EXYNOS5_DRD_PHYREG1);
+		if (result & EXYNOS5_DRD_PHYREG1_CR_ACK)
+			break;
+
+		udelay(1);
+	} while (usec-- > 0);
+
+	if (!usec)
+		dev_err(phy_drd->dev,
+			"CRPORT handshake timeout1 (0x%08x)\n", val);
+
+	usec = 100;
+
+	writel(val, phy_drd->reg_phy + EXYNOS5_DRD_PHYREG0);
+
+	do {
+		result = readl(phy_drd->reg_phy + EXYNOS5_DRD_PHYREG1);
+		if (!(result & EXYNOS5_DRD_PHYREG1_CR_ACK))
+			break;
+
+		udelay(1);
+	} while (usec-- > 0);
+
+	if (!usec)
+		dev_err(phy_drd->dev,
+			"CRPORT handshake timeout2 (0x%08x)\n", val);
+}
+
+static void crport_ctrl_write(struct exynos5_usbdrd_phy *phy_drd,
+						u32 addr, u32 data)
+{
+	/* Write Address */
+	crport_handshake(phy_drd, EXYNOS5_DRD_PHYREG0_CR_DATA_IN(addr),
+			 EXYNOS5_DRD_PHYREG0_CR_CAP_ADDR);
+
+	/* Write Data */
+	crport_handshake(phy_drd, EXYNOS5_DRD_PHYREG0_CR_DATA_IN(data),
+			 EXYNOS5_DRD_PHYREG0_CR_CAP_DATA);
+	crport_handshake(phy_drd, EXYNOS5_DRD_PHYREG0_CR_DATA_IN(data),
+			 EXYNOS5_DRD_PHYREG0_CR_WRITE);
+}
+
+/*
+ * Override PHY paramaeters using CR_PORT register to calibrate settings
+ * to meet meet SuperSpeed requirements, on Exynos5420 and Exynos5800 systems,
+ * which have 28nm USB 3.0 DRD PHY.
+ */
+static void exynos5420_usbdrd_phy_calibrate(struct exynos5_usbdrd_phy *phy_drd)
+{
+	u32 temp;
+
+	/*
+	 * Change los_bias to (0x5) for 28nm PHY from a
+	 * default value (0x0); los_level is set as default
+	 * (0x9) as also reflected in los_level[30:26] bits
+	 * of PHYPARAM0 register.
+	 */
+	temp = LOSLEVEL_OVRD_IN_LOS_BIAS_5420 |
+		LOSLEVEL_OVRD_IN_EN |
+		LOSLEVEL_OVRD_IN_LOS_LEVEL_DEFAULT;
+	crport_ctrl_write(phy_drd,
+			  EXYNOS5_DRD_PHYSS_LOSLEVEL_OVRD_IN,
+			  temp);
+
+	/*
+	 * Set tx_vboost_lvl to (0x5) for 28nm PHY Tuning,
+	 * to raise Tx signal level from its default value of (0x4)
+	 */
+	temp = TX_VBOOSTLEVEL_OVRD_IN_VBOOST_5420;
+	crport_ctrl_write(phy_drd,
+			  EXYNOS5_DRD_PHYSS_TX_VBOOSTLEVEL_OVRD_IN,
+			  temp);
+
+	/*
+	 * Set proper time to wait for RxDetect measurement, for
+	 * desired reference clock of PHY, by tuning the CRPORT
+	 * register LANE0.TX_DEBUG which is internal to PHY.
+	 * This fixes issue with few USB 3.0 devices, which are
+	 * not detected (not even generate interrupts on the bus
+	 * on insertion) without this change.
+	 * e.g. Samsung SUM-TSB16S 3.0 USB drive.
+	 */
+	switch (phy_drd->extrefclk) {
+	case EXYNOS5_FSEL_50MHZ:
+		temp = LANE0_TX_DEBUG_RXDET_MEAS_TIME_48M_50M_52M;
+		break;
+	case EXYNOS5_FSEL_20MHZ:
+	case EXYNOS5_FSEL_19MHZ2:
+		temp = LANE0_TX_DEBUG_RXDET_MEAS_TIME_19M2_20M;
+		break;
+	case EXYNOS5_FSEL_24MHZ:
+	default:
+		temp = LANE0_TX_DEBUG_RXDET_MEAS_TIME_24M;
+		break;
+	}
+
+	crport_ctrl_write(phy_drd,
+			  EXYNOS5_DRD_PHYSS_LANE0_TX_DEBUG,
+			  temp);
+}
+
+/* Calibrate PIPE3 PHY settings, if any */
+static int exynos5_usbdrd_pipe3_calibrate(struct phy_usb_instance *inst)
+{
+	struct exynos5_usbdrd_phy *phy_drd = to_usbdrd_phy(inst);
+
+	/* Call respective phy_calibrate given by certain platform */
+	if (phy_drd->drv_data->phy_calibrate)
+		phy_drd->drv_data->phy_calibrate(phy_drd);
+
+	return 0;
+}
+
+static int exynos5_usbdrd_phy_calibrate(struct phy *phy)
+{
+	struct phy_usb_instance *inst = phy_get_drvdata(phy);
+
+	if (inst->phy_cfg->phy_calibrate)
+		inst->phy_cfg->phy_calibrate(inst);
+
+	return 0;
+}
+
 static struct phy *exynos5_usbdrd_phy_xlate(struct device *dev,
 					struct of_phandle_args *args)
 {
@@ -503,6 +669,7 @@ static struct phy_ops exynos5_usbdrd_phy_ops = {
 	.exit		= exynos5_usbdrd_phy_exit,
 	.power_on	= exynos5_usbdrd_phy_power_on,
 	.power_off	= exynos5_usbdrd_phy_power_off,
+	.calibrate	= exynos5_usbdrd_phy_calibrate,
 	.owner		= THIS_MODULE,
 };
 
@@ -518,6 +685,7 @@ const struct exynos5_usbdrd_phy_config phy_cfg_exynos5[] = {
 		.phy_isol	= exynos5_usbdrd_phy_isol,
 		.phy_init	= exynos5_usbdrd_pipe3_init,
 		.set_refclk	= exynos5_usbdrd_pipe3_set_refclk,
+		.phy_calibrate	= exynos5_usbdrd_pipe3_calibrate,
 	},
 };
 
@@ -525,6 +693,7 @@ const struct exynos5_usbdrd_phy_drvdata exynos5420_usbdrd_phy = {
 	.phy_cfg		= phy_cfg_exynos5,
 	.pmu_offset_usbdrd0_phy	= EXYNOS5_USBDRD_PHY_CONTROL,
 	.pmu_offset_usbdrd1_phy	= EXYNOS5420_USBDRD1_PHY_CONTROL,
+	.calibrate		= exynos5420_usbdrd_phy_calibrate,
 };
 
 const struct exynos5_usbdrd_phy_drvdata exynos5250_usbdrd_phy = {
-- 
1.7.10.4

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