[PATCH v4 3/5] usb: gadget: Add function wakeup support

[Elson Roy Serrao]

A function which is in function suspend state has to send a
function wake notification to the host in case it needs to
exit from this state and resume data transfer. Add support to
handle such requests by exposing a new gadget op.

Signed-off-by: Elson Roy Serrao <quic_eserrao@xxxxxxxxxxx>
---
 drivers/usb/gadget/composite.c | 24 ++++++++++++++++++++++++
 drivers/usb/gadget/udc/core.c  | 21 +++++++++++++++++++++
 include/linux/usb/composite.h  |  6 ++++++
 include/linux/usb/gadget.h     |  4 ++++
 4 files changed, 55 insertions(+)

diff --git a/drivers/usb/gadget/composite.c b/drivers/usb/gadget/composite.c
index a37a8f4..51d6ee9 100644
--- a/drivers/usb/gadget/composite.c
+++ b/drivers/usb/gadget/composite.c
@@ -492,6 +492,30 @@ int usb_interface_id(struct usb_configuration *config,
 }
 EXPORT_SYMBOL_GPL(usb_interface_id);
 
+int usb_func_wakeup(struct usb_function *func)
+{
+	int ret, id;
+
+	if (!func->func_wakeup_armed) {
+		ERROR(func->config->cdev, "not armed for func remote wakeup\n");
+		return -EINVAL;
+	}
+
+	for (id = 0; id < MAX_CONFIG_INTERFACES; id++)
+		if (func->config->interface[id] == func)
+			break;
+
+	if (id == MAX_CONFIG_INTERFACES) {
+		ERROR(func->config->cdev, "Invalid function id:%d\n", id);
+		return -EINVAL;
+	}
+
+	ret = usb_gadget_func_wakeup(func->config->cdev->gadget, id);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(usb_func_wakeup);
+
 static u8 encode_bMaxPower(enum usb_device_speed speed,
 		struct usb_configuration *c)
 {
diff --git a/drivers/usb/gadget/udc/core.c b/drivers/usb/gadget/udc/core.c
index 3dcbba7..59e7a7e 100644
--- a/drivers/usb/gadget/udc/core.c
+++ b/drivers/usb/gadget/udc/core.c
@@ -846,6 +846,27 @@ int usb_gadget_activate(struct usb_gadget *gadget)
 }
 EXPORT_SYMBOL_GPL(usb_gadget_activate);
 
+/**
+ * usb_gadget_func_wakeup - sends function wake notification to the host.
+ * @gadget: controller used to wake up the host
+ * @interface_id: interface on which function wake notification is sent.
+ *
+ * On completion, function wake notification is sent. If the device is in
+ * low power state it tries to bring the device to active state before sending
+ * the wake notification. Since it is a synchronous call, caller must take care
+ * of not calling it in interrupt context.
+ *
+ * Returns zero on success, else negative errno.
+ */
+int usb_gadget_func_wakeup(struct usb_gadget *gadget, int intf_id)
+{
+	if (!gadget->ops->func_wakeup)
+		return -EOPNOTSUPP;
+
+	return gadget->ops->func_wakeup(gadget, intf_id);
+}
+EXPORT_SYMBOL_GPL(usb_gadget_func_wakeup);
+
 /* ------------------------------------------------------------------------- */
 
 #ifdef	CONFIG_HAS_DMA
diff --git a/include/linux/usb/composite.h b/include/linux/usb/composite.h
index d949e91..a2448e9 100644
--- a/include/linux/usb/composite.h
+++ b/include/linux/usb/composite.h
@@ -150,6 +150,9 @@ struct usb_os_desc_table {
  *	GetStatus() request when the recipient is Interface.
  * @func_suspend: callback to be called when
  *	SetFeature(FUNCTION_SUSPEND) is reseived
+ * @func_suspended: Indicates whether the function is in function suspend state.
+ * @func_wakeup_armed: Indicates whether the function is armed by the host for
+ *	wakeup signaling.
  *
  * A single USB function uses one or more interfaces, and should in most
  * cases support operation at both full and high speeds.  Each function is
@@ -220,6 +223,8 @@ struct usb_function {
 	int			(*get_status)(struct usb_function *);
 	int			(*func_suspend)(struct usb_function *,
 						u8 suspend_opt);
+	bool			func_suspended;
+	bool			func_wakeup_armed;
 	/* private: */
 	/* internals */
 	struct list_head		list;
@@ -241,6 +246,7 @@ int config_ep_by_speed_and_alt(struct usb_gadget *g, struct usb_function *f,
 
 int config_ep_by_speed(struct usb_gadget *g, struct usb_function *f,
 			struct usb_ep *_ep);
+int usb_func_wakeup(struct usb_function *func);
 
 #define	MAX_CONFIG_INTERFACES		16	/* arbitrary; max 255 */
 
diff --git a/include/linux/usb/gadget.h b/include/linux/usb/gadget.h
index 1d79612..2a512c5 100644
--- a/include/linux/usb/gadget.h
+++ b/include/linux/usb/gadget.h
@@ -310,6 +310,7 @@ struct usb_udc;
 struct usb_gadget_ops {
 	int	(*get_frame)(struct usb_gadget *);
 	int	(*wakeup)(struct usb_gadget *);
+	int     (*func_wakeup)(struct usb_gadget *gadget, int intf_id);
 	int	(*set_remote_wakeup)(struct usb_gadget *, int set);
 	int	(*set_selfpowered) (struct usb_gadget *, int is_selfpowered);
 	int	(*vbus_session) (struct usb_gadget *, int is_active);
@@ -617,6 +618,7 @@ int usb_gadget_disconnect(struct usb_gadget *gadget);
 int usb_gadget_deactivate(struct usb_gadget *gadget);
 int usb_gadget_activate(struct usb_gadget *gadget);
 int usb_gadget_check_config(struct usb_gadget *gadget);
+int usb_gadget_func_wakeup(struct usb_gadget *gadget, int intf_id);
 #else
 static inline int usb_gadget_frame_number(struct usb_gadget *gadget)
 { return 0; }
@@ -644,6 +646,8 @@ static inline int usb_gadget_activate(struct usb_gadget *gadget)
 { return 0; }
 static inline int usb_gadget_check_config(struct usb_gadget *gadget)
 { return 0; }
+static inline int usb_gadget_func_wakeup(struct usb_gadget *gadget, int intf_id)
+{ return 0; }
 #endif /* CONFIG_USB_GADGET */
 
 /*-------------------------------------------------------------------------*/
-- 
2.7.4