usb: chipidea: core: add controller resume support when controller is powered off

For some SoCs, the controler's power will be off during the system
suspend, and it needs some recovery operation to let the system back
to workable. We add this support in this patch.

Signed-off-by: Xu Yang <[e-mail]>
Acked-by: Peter Chen <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/usb/chipidea/core.c

···
 	return 0;
 }
 
+static enum ci_role ci_get_role(struct ci_hdrc *ci)
+{
+	enum ci_role role;
+
+	if (ci->roles[CI_ROLE_HOST] && ci->roles[CI_ROLE_GADGET]) {
+		if (ci->is_otg) {
+			role = ci_otg_role(ci);
+			hw_write_otgsc(ci, OTGSC_IDIE, OTGSC_IDIE);
+		} else {
+			/*
+			 * If the controller is not OTG capable, but support
+			 * role switch, the defalt role is gadget, and the
+			 * user can switch it through debugfs.
+			 */
+			role = CI_ROLE_GADGET;
+		}
+	} else {
+		role = ci->roles[CI_ROLE_HOST] ? CI_ROLE_HOST
+					: CI_ROLE_GADGET;
+	}
+
+	return role;
+}
+
+static void ci_handle_power_lost(struct ci_hdrc *ci)
+{
+	enum ci_role role;
+
+	disable_irq_nosync(ci->irq);
+	if (!ci_otg_is_fsm_mode(ci)) {
+		role = ci_get_role(ci);
+
+		if (ci->role != role) {
+			ci_handle_id_switch(ci);
+		} else if (role == CI_ROLE_GADGET) {
+			if (ci->is_otg && hw_read_otgsc(ci, OTGSC_BSV))
+				usb_gadget_vbus_connect(&ci->gadget);
+		}
+	}
+
+	enable_irq(ci->irq);
+}
+
 static struct usb_role_switch_desc ci_role_switch = {
 	.set = ci_usb_role_switch_set,
 	.get = ci_usb_role_switch_get,
···
 		}
 	}
 
-	if (ci->roles[CI_ROLE_HOST] && ci->roles[CI_ROLE_GADGET]) {
-		if (ci->is_otg) {
-			ci->role = ci_otg_role(ci);
-			/* Enable ID change irq */
-			hw_write_otgsc(ci, OTGSC_IDIE, OTGSC_IDIE);
-		} else {
-			/*
-			 * If the controller is not OTG capable, but support
-			 * role switch, the defalt role is gadget, and the
-			 * user can switch it through debugfs.
-			 */
-			ci->role = CI_ROLE_GADGET;
-		}
-	} else {
-		ci->role = ci->roles[CI_ROLE_HOST]
-			? CI_ROLE_HOST
-			: CI_ROLE_GADGET;
-	}
-
+	ci->role = ci_get_role(ci);
 	if (!ci_otg_is_fsm_mode(ci)) {
 		/* only update vbus status for peripheral */
 		if (ci->role == CI_ROLE_GADGET) {
···
 static int ci_resume(struct device *dev)
 {
 	struct ci_hdrc *ci = dev_get_drvdata(dev);
+	bool power_lost;
 	int ret;
+
+	/* Since ASYNCLISTADDR (host mode) and ENDPTLISTADDR (device
+	 * mode) share the same register address. We can check if
+	 * controller resume from power lost based on this address
+	 * due to this register will be reset after power lost.
+	 */
+	power_lost = !hw_read(ci, OP_ENDPTLISTADDR, ~0);
 
 	if (device_may_wakeup(dev))
 		disable_irq_wake(ci->irq);
···
 	ret = ci_controller_resume(dev);
 	if (ret)
 		return ret;
+
+	if (power_lost) {
+		/* shutdown and re-init for phy */
+		ci_usb_phy_exit(ci);
+		ci_usb_phy_init(ci);
+	}
+
+	if (power_lost)
+		ci_handle_power_lost(ci);
 
 	if (ci->supports_runtime_pm) {
 		pm_runtime_disable(dev);

drivers/usb/chipidea/otg.c

···
 	return 0;
 }
 
-static void ci_handle_id_switch(struct ci_hdrc *ci)
+void ci_handle_id_switch(struct ci_hdrc *ci)
 {
 	enum ci_role role = ci_otg_role(ci);
 

drivers/usb/chipidea/otg.h

···
 void ci_hdrc_otg_destroy(struct ci_hdrc *ci);
 enum ci_role ci_otg_role(struct ci_hdrc *ci);
 void ci_handle_vbus_change(struct ci_hdrc *ci);
+void ci_handle_id_switch(struct ci_hdrc *ci);
 static inline void ci_otg_queue_work(struct ci_hdrc *ci)
 {
 	disable_irq_nosync(ci->irq);