usb: gadget: add isochronous support to gadget zero

Add two isochronous endpoints to the gadget zero source/sink
function. They are enabled by selecting alternate interface 1, so
by default they are not enabled. Module parameters for setting all
the isoc endpoint characteristics are also provided.
Signed-off-by: Pratyush Anand <pratyush.anand@st.com>
Signed-off-by: Paul Zimmerman <paulz@synopsys.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

drivers/usb/gadget/f_loopback.c

@@ -286,7 +286,7 @@ static void disable_loopback(struct f_loopback *loop)
 	struct usb_composite_dev	*cdev;
 
 	cdev = loop->function.config->cdev;
-	disable_endpoints(cdev, loop->in_ep, loop->out_ep);
+	disable_endpoints(cdev, loop->in_ep, loop->out_ep, NULL, NULL);
 	VDBG(cdev, "%s disabled\n", loop->function.name);
 }
 
@@ -329,7 +329,7 @@ enable_loopback(struct usb_composite_dev *cdev, struct f_loopback *loop)
 	 * than 'buflen' bytes each.
 	 */
 	for (i = 0; i < qlen && result == 0; i++) {
-		req = alloc_ep_req(ep);
+		req = alloc_ep_req(ep, 0);
 		if (req) {
 			req->complete = loopback_complete;
 			result = usb_ep_queue(ep, req, GFP_ATOMIC);

drivers/usb/gadget/g_zero.h

@@ -13,10 +13,11 @@ extern unsigned buflen;
 extern const struct usb_descriptor_header *otg_desc[];
 
 /* common utilities */
-struct usb_request *alloc_ep_req(struct usb_ep *ep);
+struct usb_request *alloc_ep_req(struct usb_ep *ep, int len);
 void free_ep_req(struct usb_ep *ep, struct usb_request *req);
 void disable_endpoints(struct usb_composite_dev *cdev,
-		struct usb_ep *in, struct usb_ep *out);
+		struct usb_ep *in, struct usb_ep *out,
+		struct usb_ep *iso_in, struct usb_ep *iso_out);
 
 /* configuration-specific linkup */
 int sourcesink_add(struct usb_composite_dev *cdev, bool autoresume);

drivers/usb/gadget/zero.c

@@ -72,7 +72,7 @@
 
 static const char longname[] = "Gadget Zero";
 
-unsigned buflen = 4096;
+unsigned buflen = 4096;		/* only used for bulk endpoints */
 module_param(buflen, uint, 0);
 
 /*
@@ -170,14 +170,17 @@ static struct usb_gadget_strings *dev_strings[] = {
 
 /*-------------------------------------------------------------------------*/
 
-struct usb_request *alloc_ep_req(struct usb_ep *ep)
+struct usb_request *alloc_ep_req(struct usb_ep *ep, int len)
 {
 	struct usb_request	*req;
 
 	req = usb_ep_alloc_request(ep, GFP_ATOMIC);
 	if (req) {
-		req->length = buflen;
-		req->buf = kmalloc(buflen, GFP_ATOMIC);
+		if (len)
+			req->length = len;
+		else
+			req->length = buflen;
+		req->buf = kmalloc(req->length, GFP_ATOMIC);
 		if (!req->buf) {
 			usb_ep_free_request(ep, req);
 			req = NULL;
@@ -206,10 +209,15 @@ static void disable_ep(struct usb_composite_dev *cdev, struct usb_ep *ep)
 }
 
 void disable_endpoints(struct usb_composite_dev *cdev,
-		struct usb_ep *in, struct usb_ep *out)
+		struct usb_ep *in, struct usb_ep *out,
+		struct usb_ep *iso_in, struct usb_ep *iso_out)
 {
 	disable_ep(cdev, in);
 	disable_ep(cdev, out);
+	if (iso_in)
+		disable_ep(cdev, iso_in);
+	if (iso_out)
+		disable_ep(cdev, iso_out);
 }
 
 /*-------------------------------------------------------------------------*/
@@ -311,7 +319,6 @@ static int __init zero_bind(struct usb_composite_dev *cdev)
 		device_desc.bcdDevice = cpu_to_le16(0x9999);
 	}
 
-
 	INFO(cdev, "%s, version: " DRIVER_VERSION "\n", longname);
 
 	snprintf(manufacturer, sizeof manufacturer, "%s %s with %s",