usb: misc: usbtest: format the data pattern according to max packet size

commit b9a6e8e1 upstream.

With this change, the host and gadget doesn't need to agree with transfer
length for comparing the data, since they doesn't know each other's
transfer size, but know max packet size.
Signed-off-by: Peter Chen <peter.chen@freescale.com>
Acked-by: Michal Nazarewicz <mina86@mina86.com>
(Fixed the 'line over 80 characters warning' by Peter Chen)
Tested-by: Peter Chen <peter.chen@freescale.com>
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>

drivers/usb/misc/usbtest.c

@@ -303,11 +303,20 @@ static unsigned mod_pattern;
 module_param_named(pattern, mod_pattern, uint, S_IRUGO | S_IWUSR);
 MODULE_PARM_DESC(mod_pattern, "i/o pattern (0 == zeroes)");
 
-static inline void simple_fill_buf(struct urb *urb)
+static unsigned get_maxpacket(struct usb_device *udev, int pipe)
+{
+	struct usb_host_endpoint	*ep;
+
+	ep = usb_pipe_endpoint(udev, pipe);
+	return le16_to_cpup(&ep->desc.wMaxPacketSize);
+}
+
+static void simple_fill_buf(struct urb *urb)
 {
 	unsigned	i;
 	u8		*buf = urb->transfer_buffer;
 	unsigned	len = urb->transfer_buffer_length;
+	unsigned	maxpacket;
 
 	switch (pattern) {
 	default:
@@ -316,8 +325,9 @@ static inline void simple_fill_buf(struct urb *urb)
 		memset(buf, 0, len);
 		break;
 	case 1:			/* mod63 */
+		maxpacket = get_maxpacket(urb->dev, urb->pipe);
 		for (i = 0; i < len; i++)
-			*buf++ = (u8) (i % 63);
+			*buf++ = (u8) ((i % maxpacket) % 63);
 		break;
 	}
 }
@@ -349,6 +359,7 @@ static int simple_check_buf(struct usbtest_dev *tdev, struct urb *urb)
 	u8		expected;
 	u8		*buf = urb->transfer_buffer;
 	unsigned	len = urb->actual_length;
+	unsigned	maxpacket = get_maxpacket(urb->dev, urb->pipe);
 
 	int ret = check_guard_bytes(tdev, urb);
 	if (ret)
@@ -366,7 +377,7 @@ static int simple_check_buf(struct usbtest_dev *tdev, struct urb *urb)
 		 * with set_interface or set_config.
 		 */
 		case 1:			/* mod63 */
-			expected = i % 63;
+			expected = (i % maxpacket) % 63;
 			break;
 		/* always fail unsupported patterns */
 		default:
@@ -478,11 +489,13 @@ static void free_sglist(struct scatterlist *sg, int nents)
 }
 
 static struct scatterlist *
-alloc_sglist(int nents, int max, int vary)
+alloc_sglist(int nents, int max, int vary, struct usbtest_dev *dev, int pipe)
 {
 	struct scatterlist	*sg;
 	unsigned		i;
 	unsigned		size = max;
+	unsigned		maxpacket =
+		get_maxpacket(interface_to_usbdev(dev->intf), pipe);
 
 	if (max == 0)
 		return NULL;
@@ -511,7 +524,7 @@ alloc_sglist(int nents, int max, int vary)
 			break;
 		case 1:
 			for (j = 0; j < size; j++)
-				*buf++ = (u8) (j % 63);
+				*buf++ = (u8) ((j % maxpacket) % 63);
 			break;
 		}
 
@@ -2175,7 +2188,8 @@ usbtest_ioctl(struct usb_interface *intf, unsigned int code, void *buf)
 			"TEST 5:  write %d sglists %d entries of %d bytes\n",
 				param->iterations,
 				param->sglen, param->length);
-		sg = alloc_sglist(param->sglen, param->length, 0);
+		sg = alloc_sglist(param->sglen, param->length,
+				0, dev, dev->out_pipe);
 		if (!sg) {
 			retval = -ENOMEM;
 			break;
@@ -2193,7 +2207,8 @@ usbtest_ioctl(struct usb_interface *intf, unsigned int code, void *buf)
 			"TEST 6:  read %d sglists %d entries of %d bytes\n",
 				param->iterations,
 				param->sglen, param->length);
-		sg = alloc_sglist(param->sglen, param->length, 0);
+		sg = alloc_sglist(param->sglen, param->length,
+				0, dev, dev->in_pipe);
 		if (!sg) {
 			retval = -ENOMEM;
 			break;
@@ -2210,7 +2225,8 @@ usbtest_ioctl(struct usb_interface *intf, unsigned int code, void *buf)
 			"TEST 7:  write/%d %d sglists %d entries 0..%d bytes\n",
 				param->vary, param->iterations,
 				param->sglen, param->length);
-		sg = alloc_sglist(param->sglen, param->length, param->vary);
+		sg = alloc_sglist(param->sglen, param->length,
+				param->vary, dev, dev->out_pipe);
 		if (!sg) {
 			retval = -ENOMEM;
 			break;
@@ -2227,7 +2243,8 @@ usbtest_ioctl(struct usb_interface *intf, unsigned int code, void *buf)
 			"TEST 8:  read/%d %d sglists %d entries 0..%d bytes\n",
 				param->vary, param->iterations,
 				param->sglen, param->length);
-		sg = alloc_sglist(param->sglen, param->length, param->vary);
+		sg = alloc_sglist(param->sglen, param->length,
+				param->vary, dev, dev->in_pipe);
 		if (!sg) {
 			retval = -ENOMEM;
 			break;