[PATCH] usb: dwc3: Disable phy suspend after power-on reset

[Thinh Nguyen <Thinh.Nguyen@synopsys.com>]

For DRD controllers, the programming guide recommended that
GUSB3PIPECTL.SUSPENDABLE and GUSB2PHYCFG.SUSPHY to be cleared after
power-on reset and only set after the controller initialization is
completed. This can be done after device soft-reset in dwc3_core_init().
This patch makes sure to clear GUSB3PIPECTL.SUSPENDABLE and
GUSB2PHYCFG.SUSPHY before core initialization and only set them after
the device soft-reset is completed.

Reference: DWC_usb3 3.30a and DWC_usb31 1.90a programming guide section
1.2.49 and 1.2.45

Signed-off-by: Thinh Nguyen <thinhn@synopsys.com>
---
 drivers/usb/dwc3/core.c | 37 +++++++++++++++++++++++++++++++++++++
 1 file changed, 37 insertions(+)

diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
index 252c397860ef..edbc3709f28e 100644
--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -568,8 +568,11 @@ static int dwc3_core_ulpi_init(struct dwc3 *dwc)
  */
 static int dwc3_phy_setup(struct dwc3 *dwc)
 {
+	unsigned int hw_mode;
 	u32 reg;
 
+	hw_mode = DWC3_GHWPARAMS0_MODE(dwc->hwparams.hwparams0);
+
 	reg = dwc3_readl(dwc->regs, DWC3_GUSB3PIPECTL(0));
 
 	/*
@@ -587,6 +590,14 @@ static int dwc3_phy_setup(struct dwc3 *dwc)
 	if (dwc->revision > DWC3_REVISION_194A)
 		reg |= DWC3_GUSB3PIPECTL_SUSPHY;
 
+	/*
+	 * For DRD controllers, GUSB3PIPECTL.SUSPENDENABLE must be cleared after
+	 * power-on reset, and it can be set after core initialization, which is
+	 * after device soft-reset during initialization.
+	 */
+	if (hw_mode == DWC3_GHWPARAMS0_MODE_DRD)
+		reg &= ~DWC3_GUSB3PIPECTL_SUSPHY;
+
 	if (dwc->u2ss_inp3_quirk)
 		reg |= DWC3_GUSB3PIPECTL_U2SSINP3OK;
 
@@ -670,6 +681,14 @@ static int dwc3_phy_setup(struct dwc3 *dwc)
 	if (dwc->revision > DWC3_REVISION_194A)
 		reg |= DWC3_GUSB2PHYCFG_SUSPHY;
 
+	/*
+	 * For DRD controllers, GUSB2PHYCFG.SUSPHY must be cleared after
+	 * power-on reset, and it can be set after core initialization, which is
+	 * after device soft-reset during initialization.
+	 */
+	if (hw_mode == DWC3_GHWPARAMS0_MODE_DRD)
+		reg &= ~DWC3_GUSB2PHYCFG_SUSPHY;
+
 	if (dwc->dis_u2_susphy_quirk)
 		reg &= ~DWC3_GUSB2PHYCFG_SUSPHY;
 
@@ -905,9 +924,12 @@ static void dwc3_set_incr_burst_type(struct dwc3 *dwc)
  */
 static int dwc3_core_init(struct dwc3 *dwc)
 {
+	unsigned int		hw_mode;
 	u32			reg;
 	int			ret;
 
+	hw_mode = DWC3_GHWPARAMS0_MODE(dwc->hwparams.hwparams0);
+
 	/*
 	 * Write Linux Version Code to our GUID register so it's easy to figure
 	 * out which kernel version a bug was found.
@@ -943,6 +965,21 @@ static int dwc3_core_init(struct dwc3 *dwc)
 	if (ret)
 		goto err0a;
 
+	if (hw_mode == DWC3_GHWPARAMS0_MODE_DRD &&
+	    dwc->revision > DWC3_REVISION_194A) {
+		if (!dwc->dis_u3_susphy_quirk) {
+			reg = dwc3_readl(dwc->regs, DWC3_GUSB3PIPECTL(0));
+			reg |= DWC3_GUSB3PIPECTL_SUSPHY;
+			dwc3_writel(dwc->regs, DWC3_GUSB3PIPECTL(0), reg);
+		}
+
+		if (!dwc->dis_u2_susphy_quirk) {
+			reg = dwc3_readl(dwc->regs, DWC3_GUSB2PHYCFG(0));
+			reg |= DWC3_GUSB2PHYCFG_SUSPHY;
+			dwc3_writel(dwc->regs, DWC3_GUSB2PHYCFG(0), reg);
+		}
+	}
+
 	dwc3_core_setup_global_control(dwc);
 	dwc3_core_num_eps(dwc);
 
-- 
2.11.0