usb: gadget: move USB_BUFSIZ into global composite.h

This patch moves USB_BUFSIZ into global header file as
USB_COMP_EP0_BUFSIZ. There is currently only one user (f_sourcesink)
besides composite which need it. Ideally f_sourcesink would have its
own ep0 buffer. Lets keep it that way it was for now.

Acked-by: Michal Nazarewicz <mina86@mina86.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Felipe Balbi <balbi@ti.com>

drivers/usb/gadget/composite.c

@@ -28,9 +28,6 @@
  * with the relevant device-wide data.
  */
 
-/* big enough to hold our biggest descriptor */
-#define USB_BUFSIZ	1024
-
 /* Some systems will need runtime overrides for the  product identifiers
  * published in the device descriptor, either numbers or strings or both.
  * String parameters are in UTF-8 (superset of ASCII's 7 bit characters).
@@ -355,10 +352,11 @@ static int config_buf(struct usb_configuration *config,
 {
 	struct usb_config_descriptor	*c = buf;
 	void				*next = buf + USB_DT_CONFIG_SIZE;
-	int				len = USB_BUFSIZ - USB_DT_CONFIG_SIZE;
+	int				len;
 	struct usb_function		*f;
 	int				status;
 
+	len = USB_COMP_EP0_BUFSIZ - USB_DT_CONFIG_SIZE;
 	/* write the config descriptor */
 	c = buf;
 	c->bLength = USB_DT_CONFIG_SIZE;
@@ -1445,13 +1443,13 @@ static int composite_bind(struct usb_gadget *gadget,
 	cdev->req = usb_ep_alloc_request(gadget->ep0, GFP_KERNEL);
 	if (!cdev->req)
 		goto fail;
-	cdev->req->buf = kmalloc(USB_BUFSIZ, GFP_KERNEL);
+	cdev->req->buf = kmalloc(USB_COMP_EP0_BUFSIZ, GFP_KERNEL);
 	if (!cdev->req->buf)
 		goto fail;
 	cdev->req->complete = composite_setup_complete;
 	gadget->ep0->driver_data = cdev;
 
-	cdev->bufsiz = USB_BUFSIZ;
+	cdev->bufsiz = USB_COMP_EP0_BUFSIZ;
 	cdev->driver = composite;
 
 	/*

drivers/usb/gadget/f_sourcesink.c

@@ -795,7 +795,7 @@ static int sourcesink_setup(struct usb_configuration *c,
 	u16			w_value = le16_to_cpu(ctrl->wValue);
 	u16			w_length = le16_to_cpu(ctrl->wLength);
 
-	req->length = USB_BUFSIZ;
+	req->length = USB_COMP_EP0_BUFSIZ;
 
 	/* composite driver infrastructure handles everything except
 	 * the two control test requests.

include/linux/usb/composite.h

@@ -46,6 +46,9 @@
  */
 #define USB_GADGET_DELAYED_STATUS       0x7fff	/* Impossibly large value */
 
+/* big enough to hold our biggest descriptor */
+#define USB_COMP_EP0_BUFSIZ	1024
+
 struct usb_configuration;
 
 /**