usb: introduce USB_NOTIFY_CLASS_DRIVER

this invokes specified class driver's notify_event method.
initial purpose is to trigger a callback from isr, like a timer event.

Change-Id: Id600e9f0d8840a12da779d5a15783edf14bd76b5

firmware/export/usb.h

@@ -119,6 +119,7 @@ enum
     USB_NOTIFY_SET_ADDR,     /* Event */
     USB_NOTIFY_SET_CONFIG,   /* Event */
     USB_NOTIFY_BUS_RESET,    /* Event */
+    USB_NOTIFY_CLASS_DRIVER, /* Event - notify_event() of specified class driver */
 #endif
 #ifdef USB_FIREWIRE_HANDLING
     USB_REQUEST_REBOOT,      /* Event */
@@ -238,12 +239,23 @@ void usb_set_mode(int mode);
 /* USB driver call this function to notify that a transfer has completed */
 void usb_signal_transfer_completion(
     struct usb_transfer_completion_event_data *event_data);
+
 /* Clear all signaled transfer completion events from event queue */
 void usb_clear_pending_transfer_completion_events(void);
+
 /* notify the USB code that some important event has occurred which influences the
  * USB state (like USB_NOTIFY_SET_ADDR). USB drivers should call usb_core_notify_*
- * functions and not this function. */
+ * functions and not this function.
+ * for USB_NOTIFY_CLASS_DRIVER, use usb_signal_class_notify() instead */
 void usb_signal_notify(long id, intptr_t data);
+
+/* wrapper for usb_signal_notify(USB_NOTIFY_CLASS_DRIVER)
+ * class_num: target driver. USB_DRIVER_*
+ * data: optional data. note that its upper 8 bits will be masked */
+static inline void usb_signal_class_notify(int8_t class_num, uint32_t data) {
+    usb_signal_notify(USB_NOTIFY_CLASS_DRIVER, class_num << 24 | (data & 0x00ffffff));
+}
+
 /* returns whether a USB_DRIVER_* is enabled (like HID, mass storage, ...) */
 bool usb_driver_enabled(int driver);
 /* returns whether exclusive storage is available for USB */

firmware/usb.c

@@ -423,6 +423,7 @@ static void NORETURN_ATTR usb_thread(void)
         case USB_NOTIFY_SET_ADDR:
         case USB_NOTIFY_SET_CONFIG:
         case USB_NOTIFY_BUS_RESET:
+        case USB_NOTIFY_CLASS_DRIVER:
             if(usb_state <= USB_EXTRACTED)
                 break;
             usb_core_handle_notify(ev.id, ev.data);

firmware/usbstack/usb_class_driver.h

@@ -118,6 +118,10 @@ struct usb_class_driver {
      * Returns value on success and -1 on error.
      * Mandatory function if alternate interface support is needed */
     int (*get_interface)(int interface);
+
+    /* Invoked by USB_NOTIFY_CLASS_DRIVER
+       Optional function */
+    void (*notify_event)(intptr_t data);
 };
 
 #define PACK_DATA(dest, data) pack_data(dest, &(data), sizeof(data))

firmware/usbstack/usb_core.c

@@ -1181,6 +1181,16 @@ void usb_core_handle_notify(long id, intptr_t data)
             usb_charging_maxcurrent_change(usb_charging_maxcurrent());
 #endif
             break;
+        case USB_NOTIFY_CLASS_DRIVER: {
+            uint8_t index = data >> 24;
+            if(index >= USB_NUM_DRIVERS) {
+                logf("usb_core: invalid notification destination index=%u", index);
+                return;
+            }
+            if(is_active(drivers[index]) && drivers[index].notify_event != NULL) {
+                drivers[index].notify_event(data & 0x00ffffff);
+            }
+        } break;
         default:
             break;
     }