phy: exynos5-usbdrd: Calibrate LOS levels for exynos5420/5800

Adding phy calibration sequence for USB 3.0 DRD PHY present on
Exynos5420/5800 systems.
This calibration facilitates setting certain PHY parameters viz.
the Loss-of-Signal (LOS) Detector Threshold Level, as well as
Tx-Vboost-Level for Super-Speed operations.
Additionally we also 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

[Also removed unnecessary extra lines in the register macro definitions]
Signed-off-by: Vivek Gautam <gautam.vivek@samsung.com>
[adapted to use phy_calibrate as entry point]
Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@samsung.com>
Acked-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>

drivers/phy/samsung/phy-exynos5-usbdrd.c

@@ -90,7 +90,17 @@
 #define PHYCLKRST_COMMONONN			BIT(0)
 
 #define EXYNOS5_DRD_PHYREG0			0x14
+#define PHYREG0_SSC_REF_CLK_SEL			BIT(21)
+#define PHYREG0_SSC_RANGE			BIT(20)
+#define PHYREG0_CR_WRITE			BIT(19)
+#define PHYREG0_CR_READ				BIT(18)
+#define PHYREG0_CR_DATA_IN(_x)			((_x) << 2)
+#define PHYREG0_CR_CAP_DATA			BIT(1)
+#define PHYREG0_CR_CAP_ADDR			BIT(0)
+
 #define EXYNOS5_DRD_PHYREG1			0x18
+#define PHYREG1_CR_DATA_OUT(_x)			((_x) << 1)
+#define PHYREG1_CR_ACK				BIT(0)
 
 #define EXYNOS5_DRD_PHYPARAM0			0x1c
 
@@ -119,6 +129,25 @@
 #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)
 
@@ -527,6 +556,151 @@ static int exynos5_usbdrd_phy_power_off(struct phy *phy)
 	return 0;
 }
 
+static int crport_handshake(struct exynos5_usbdrd_phy *phy_drd,
+			    u32 val, u32 cmd)
+{
+	u32 usec = 100;
+	unsigned int result;
+
+	writel(val | cmd, phy_drd->reg_phy + EXYNOS5_DRD_PHYREG0);
+
+	do {
+		result = readl(phy_drd->reg_phy + EXYNOS5_DRD_PHYREG1);
+		if (result & PHYREG1_CR_ACK)
+			break;
+
+		udelay(1);
+	} while (usec-- > 0);
+
+	if (!usec) {
+		dev_err(phy_drd->dev,
+			"CRPORT handshake timeout1 (0x%08x)\n", val);
+		return -ETIME;
+	}
+
+	usec = 100;
+
+	writel(val, phy_drd->reg_phy + EXYNOS5_DRD_PHYREG0);
+
+	do {
+		result = readl(phy_drd->reg_phy + EXYNOS5_DRD_PHYREG1);
+		if (!(result & PHYREG1_CR_ACK))
+			break;
+
+		udelay(1);
+	} while (usec-- > 0);
+
+	if (!usec) {
+		dev_err(phy_drd->dev,
+			"CRPORT handshake timeout2 (0x%08x)\n", val);
+		return -ETIME;
+	}
+
+	return 0;
+}
+
+static int crport_ctrl_write(struct exynos5_usbdrd_phy *phy_drd,
+			     u32 addr, u32 data)
+{
+	int ret;
+
+	/* Write Address */
+	writel(PHYREG0_CR_DATA_IN(addr),
+	       phy_drd->reg_phy + EXYNOS5_DRD_PHYREG0);
+	ret = crport_handshake(phy_drd, PHYREG0_CR_DATA_IN(addr),
+			       PHYREG0_CR_CAP_ADDR);
+	if (ret)
+		return ret;
+
+	/* Write Data */
+	writel(PHYREG0_CR_DATA_IN(data),
+	       phy_drd->reg_phy + EXYNOS5_DRD_PHYREG0);
+	ret = crport_handshake(phy_drd, PHYREG0_CR_DATA_IN(data),
+			       PHYREG0_CR_CAP_DATA);
+	if (ret)
+		return ret;
+
+	ret = crport_handshake(phy_drd, PHYREG0_CR_DATA_IN(data),
+			       PHYREG0_CR_WRITE);
+
+	return ret;
+}
+
+/*
+ * Calibrate few PHY parameters using CR_PORT register to meet
+ * SuperSpeed requirements on Exynos5420 and Exynos5800 systems,
+ * which have 28nm USB 3.0 DRD PHY.
+ */
+static int exynos5420_usbdrd_phy_calibrate(struct exynos5_usbdrd_phy *phy_drd)
+{
+	unsigned int temp;
+	int ret = 0;
+
+	/*
+	 * 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;
+	ret = crport_ctrl_write(phy_drd,
+				EXYNOS5_DRD_PHYSS_LOSLEVEL_OVRD_IN,
+				temp);
+	if (ret) {
+		dev_err(phy_drd->dev,
+			"Failed setting Loss-of-Signal level for SuperSpeed\n");
+		return ret;
+	}
+
+	/*
+	 * 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;
+	ret = crport_ctrl_write(phy_drd,
+				EXYNOS5_DRD_PHYSS_TX_VBOOSTLEVEL_OVRD_IN,
+				temp);
+	if (ret) {
+		dev_err(phy_drd->dev,
+			"Failed setting Tx-Vboost-Level for SuperSpeed\n");
+		return ret;
+	}
+
+	/*
+	 * Set proper time to wait for RxDetect measurement, for
+	 * desired reference clock of PHY, by tuning the CR_PORT
+	 * 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;
+	}
+
+	ret = crport_ctrl_write(phy_drd,
+				EXYNOS5_DRD_PHYSS_LANE0_TX_DEBUG,
+				temp);
+	if (ret)
+		dev_err(phy_drd->dev,
+			"Fail to set RxDet measurement time for SuperSpeed\n");
+
+	return ret;
+}
+
 static struct phy *exynos5_usbdrd_phy_xlate(struct device *dev,
 					struct of_phandle_args *args)
 {
@@ -538,11 +712,20 @@ static struct phy *exynos5_usbdrd_phy_xlate(struct device *dev,
 	return phy_drd->phys[args->args[0]].phy;
 }
 
+static int exynos5_usbdrd_phy_calibrate(struct phy *phy)
+{
+	struct phy_usb_instance *inst = phy_get_drvdata(phy);
+	struct exynos5_usbdrd_phy *phy_drd = to_usbdrd_phy(inst);
+
+	return exynos5420_usbdrd_phy_calibrate(phy_drd);
+}
+
 static const struct phy_ops exynos5_usbdrd_phy_ops = {
 	.init		= exynos5_usbdrd_phy_init,
 	.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,
 };
 

drivers/usb/dwc3/core.c

@@ -147,6 +147,7 @@ static void __dwc3_set_mode(struct work_struct *work)
 				otg_set_vbus(dwc->usb2_phy->otg, true);
 			phy_set_mode(dwc->usb2_generic_phy, PHY_MODE_USB_HOST);
 			phy_set_mode(dwc->usb3_generic_phy, PHY_MODE_USB_HOST);
+			phy_calibrate(dwc->usb2_generic_phy);
 		}
 		break;
 	case DWC3_GCTL_PRTCAP_DEVICE:
@@ -945,6 +946,7 @@ static int dwc3_core_init_mode(struct dwc3 *dwc)
 				dev_err(dev, "failed to initialize host\n");
 			return ret;
 		}
+		phy_calibrate(dwc->usb2_generic_phy);
 		break;
 	case USB_DR_MODE_OTG:
 		INIT_WORK(&dwc->drd_work, __dwc3_set_mode);