usb: dwc3: Add hibernation support when operating as gadget

This patch adds hibernation support when dwc3 controller is
operating in gadget mode

Signed-off-by: Anurag Kumar Vulisha <anuragku@xilinx.com>
Signed-off-by: Mayank Adesara <mayank.adesara@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>

drivers/usb/dwc3/Makefile

@@ -15,7 +15,7 @@ ifneq ($(filter y,$(CONFIG_USB_DWC3_HOST) $(CONFIG_USB_DWC3_DUAL_ROLE) $(CONFIG_
 endif
 
 ifneq ($(filter y,$(CONFIG_USB_DWC3_GADGET) $(CONFIG_USB_DWC3_DUAL_ROLE) $(CONFIG_USB_DWC3_OTG)),)
-	dwc3-y				+= gadget.o ep0.o
+	dwc3-y				+= gadget.o ep0.o gadget_hibernation.o
 endif
 
 ifneq ($(CONFIG_USB_DWC3_OTG),)

drivers/usb/dwc3/core.c

@@ -230,7 +230,7 @@ static int dwc3_core_soft_reset(struct dwc3 *dwc)
 	 * XHCI driver will reset the host block. If dwc3 was configured for
 	 * host-only mode, then we can return early.
 	 */
-	if (dwc->dr_mode == USB_DR_MODE_HOST)
+	if (dwc->dr_mode == USB_DR_MODE_HOST || dwc->is_hibernated == true)
 		return 0;
 
 	reg = dwc3_readl(dwc->regs, DWC3_DCTL);
@@ -745,8 +745,15 @@ static void dwc3_core_setup_global_control(struct dwc3 *dwc)
 			reg &= ~DWC3_GCTL_DSBLCLKGTNG;
 		break;
 	case DWC3_GHWPARAMS1_EN_PWROPT_HIB:
+		if (!device_property_read_bool(dwc->dev,
+					       "snps,enable-hibernation")) {
+			dev_dbg(dwc->dev, "Hibernation not enabled\n");
+			break;
+		}
+
 		/* enable hibernation here */
 		dwc->nr_scratch = DWC3_GHWPARAMS4_HIBER_SCRATCHBUFS(hwparams4);
+		dwc->has_hibernation = 1;
 
 		/*
 		 * REVISIT Enabling this bit so that host-mode hibernation
@@ -796,7 +803,7 @@ static int dwc3_core_get_phy(struct dwc3 *dwc);
  *
  * Returns 0 on success otherwise negative errno.
  */
-static int dwc3_core_init(struct dwc3 *dwc)
+int dwc3_core_init(struct dwc3 *dwc)
 {
 	u32			reg;
 	int			ret;

drivers/usb/dwc3/core.h

@@ -396,6 +396,7 @@
 
 /* Device Status Register */
 #define DWC3_DSTS_DCNRD			BIT(29)
+#define DWC3_DSTS_SRE			BIT(28)
 
 /* This applies for core versions 1.87a and earlier */
 #define DWC3_DSTS_PWRUPREQ		BIT(24)
@@ -884,6 +885,7 @@ struct dwc3_scratchpad_array {
  * @dis_tx_ipgap_linecheck_quirk: set if we disable u2mac linestate
  *			check during HS transmit.
  * @tx_de_emphasis_quirk: set if we enable Tx de-emphasis quirk
+ * @is_hibernated: true when dwc3 is hibernated; abort processing events
  * @tx_de_emphasis: Tx de-emphasis value
  * 	0	- -6dB de-emphasis
  * 	1	- -3.5dB de-emphasis
@@ -892,6 +894,11 @@ struct dwc3_scratchpad_array {
  * @imod_interval: set the interrupt moderation interval in 250ns
  *                 increments or 0 to disable.
  * @is_d3: set if the controller is in d3 state
+ * @saved_regs: registers to be saved/restored during hibernation/wakeup events
+ * @irq_wakeup: wakeup IRQ number, triggered when host asks to wakeup from
+ *              hibernation
+ * @force_hiber_wake: flag set when the gadget driver is forcefully triggering
+		a hibernation wakeup event
  */
 struct dwc3 {
 	struct work_struct	drd_work;
@@ -1048,9 +1055,13 @@ struct dwc3 {
 
 	unsigned		tx_de_emphasis_quirk:1;
 	unsigned		tx_de_emphasis:2;
+	unsigned		is_hibernated:1;
 
 	u16			imod_interval;
 	bool			is_d3;
+	u32			*saved_regs;
+	u32			irq_wakeup;
+	bool			force_hiber_wake;
 };
 
 #define work_to_dwc(w)		(container_of((w), struct dwc3, drd_work))
@@ -1267,6 +1278,7 @@ int dwc3_gadget_set_link_state(struct dwc3 *dwc, enum dwc3_link_state state);
 int dwc3_send_gadget_ep_cmd(struct dwc3_ep *dep, unsigned cmd,
 		struct dwc3_gadget_ep_cmd_params *params);
 int dwc3_send_gadget_generic_command(struct dwc3 *dwc, unsigned cmd, u32 param);
+int dwc3_core_init(struct dwc3 *dwc);
 #else
 static inline int dwc3_gadget_init(struct dwc3 *dwc)
 { return 0; }