usb: dwc3: Add support for device L1 exit

For the usb31 IP and from version 2.90a of the usb3 IP, the core
supports HW exit from L1 in HS. Enable it, otherwise the controller may
never exit from LPM to do a transfer.

Signed-off-by: John Youn <johnyoun@synopsys.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

drivers/usb/dwc3/core.c

@@ -766,6 +766,16 @@ static int dwc3_core_init(struct dwc3 *dwc)
 		dwc3_writel(dwc->regs, DWC3_GUCTL2, reg);
 	}
 
+	/*
+	 * Enable hardware control of sending remote wakeup in HS when
+	 * the device is in the L1 state.
+	 */
+	if (dwc->revision >= DWC3_REVISION_290A) {
+		reg = dwc3_readl(dwc->regs, DWC3_GUCTL1);
+		reg |= DWC3_GUCTL1_DEV_L1_EXIT_BY_HW;
+		dwc3_writel(dwc->regs, DWC3_GUCTL1, reg);
+	}
+
 	return 0;
 
 err4:

drivers/usb/dwc3/core.h

@@ -198,6 +198,9 @@
 #define DWC3_GCTL_GBLHIBERNATIONEN	(1 << 1)
 #define DWC3_GCTL_DSBLCLKGTNG		(1 << 0)
 
+/* Global User Control 1 Register */
+#define DWC3_GUCTL1_DEV_L1_EXIT_BY_HW	(1 << 24)
+
 /* Global USB2 PHY Configuration Register */
 #define DWC3_GUSB2PHYCFG_PHYSOFTRST	(1 << 31)
 #define DWC3_GUSB2PHYCFG_U2_FREECLK_EXISTS	(1 << 30)
@@ -908,6 +911,7 @@ struct dwc3 {
 #define DWC3_REVISION_260A	0x5533260a
 #define DWC3_REVISION_270A	0x5533270a
 #define DWC3_REVISION_280A	0x5533280a
+#define DWC3_REVISION_290A	0x5533290a
 #define DWC3_REVISION_300A	0x5533300a
 #define DWC3_REVISION_310A	0x5533310a