usb: dwc3: add P3 in U2 SS inactive quirk

This patch adds P3 in U2 SS inactive quirk, and some special platforms can
configure that if it is needed.

[ balbi@ti.com : added DeviceTree binding documentation ]

Signed-off-by: Huang Rui <ray.huang@amd.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

Documentation/devicetree/bindings/usb/dwc3.txt

@@ -19,6 +19,7 @@ Optional properties:
  - snps,has-lpm-erratum: true when DWC3 was configured with LPM Erratum enabled
  - snps,lpm-nyet-threshold: LPM NYET threshold
  - snps,u2exit_lfps_quirk: set if we want to enable u2exit lfps quirk
+ - snps,u2ss_inp3_quirk: set if we enable P3 OK for U2/SS Inactive quirk
 
 This is usually a subnode to DWC3 glue to which it is connected.
 

drivers/usb/dwc3/core.c

@@ -364,6 +364,24 @@ static void dwc3_cache_hwparams(struct dwc3 *dwc)
 	parms->hwparams8 = dwc3_readl(dwc->regs, DWC3_GHWPARAMS8);
 }
 
+/**
+ * dwc3_phy_setup - Configure USB PHY Interface of DWC3 Core
+ * @dwc: Pointer to our controller context structure
+ */
+static void dwc3_phy_setup(struct dwc3 *dwc)
+{
+	u32 reg;
+
+	reg = dwc3_readl(dwc->regs, DWC3_GUSB3PIPECTL(0));
+
+	if (dwc->u2ss_inp3_quirk)
+		reg |= DWC3_GUSB3PIPECTL_U2SSINP3OK;
+
+	dwc3_writel(dwc->regs, DWC3_GUSB3PIPECTL(0), reg);
+
+	mdelay(100);
+}
+
 /**
  * dwc3_core_init - Low-level initialization of DWC3 Core
  * @dwc: Pointer to our controller context structure
@@ -489,6 +507,8 @@ static int dwc3_core_init(struct dwc3 *dwc)
 
 	dwc3_writel(dwc->regs, DWC3_GCTL, reg);
 
+	dwc3_phy_setup(dwc);
+
 	ret = dwc3_alloc_scratch_buffers(dwc);
 	if (ret)
 		goto err1;
@@ -734,6 +754,8 @@ static int dwc3_probe(struct platform_device *pdev)
 				"snps,disable_scramble_quirk");
 		dwc->u2exit_lfps_quirk = of_property_read_bool(node,
 				"snps,u2exit_lfps_quirk");
+		dwc->u2ss_inp3_quirk = of_property_read_bool(node,
+				"snps,u2ss_inp3_quirk");
 	} else if (pdata) {
 		dwc->maximum_speed = pdata->maximum_speed;
 		dwc->has_lpm_erratum = pdata->has_lpm_erratum;
@@ -745,6 +767,7 @@ static int dwc3_probe(struct platform_device *pdev)
 
 		dwc->disable_scramble_quirk = pdata->disable_scramble_quirk;
 		dwc->u2exit_lfps_quirk = pdata->u2exit_lfps_quirk;
+		dwc->u2ss_inp3_quirk = pdata->u2ss_inp3_quirk;
 	}
 
 	/* default to superspeed if no maximum_speed passed */

drivers/usb/dwc3/core.h

@@ -176,6 +176,7 @@
 
 /* Global USB3 PIPE Control Register */
 #define DWC3_GUSB3PIPECTL_PHYSOFTRST	(1 << 31)
+#define DWC3_GUSB3PIPECTL_U2SSINP3OK	(1 << 29)
 #define DWC3_GUSB3PIPECTL_SUSPHY	(1 << 17)
 
 /* Global TX Fifo Size Register */
@@ -681,6 +682,7 @@ struct dwc3_scratchpad_array {
  * @three_stage_setup: set if we perform a three phase setup
  * @disable_scramble_quirk: set if we enable the disable scramble quirk
  * @u2exit_lfps_quirk: set if we enable u2exit lfps quirk
+ * @u2ss_inp3_quirk: set if we enable P3 OK for U2/SS Inactive quirk
  */
 struct dwc3 {
 	struct usb_ctrlrequest	*ctrl_req;
@@ -790,6 +792,7 @@ struct dwc3 {
 
 	unsigned		disable_scramble_quirk:1;
 	unsigned		u2exit_lfps_quirk:1;
+	unsigned		u2ss_inp3_quirk:1;
 };
 
 /* -------------------------------------------------------------------------- */

drivers/usb/dwc3/platform_data.h

@@ -30,4 +30,5 @@ struct dwc3_platform_data {
 	unsigned disable_scramble_quirk:1;
 	unsigned has_lpm_erratum:1;
 	unsigned u2exit_lfps_quirk:1;
+	unsigned u2ss_inp3_quirk:1;
 };