usb: usbtmc: Fix ioctl USBTMC_IOCTL_ABORT_BULK_IN

Add parameter 'tag' to function usbtmc_ioctl_abort_bulk_in_tag()
for future versions.

Remove calculation of max_size (=wMaxPacketSize) and wrong
condition (actual == max_size) in while loop. An abort operation
should always flush the complete Bulk-IN until a short packet is
received.

Return error code ENOMSG when transfer (specified by given tag)
is not in progress and device returns code
USBTMC_STATUS_TRANSFER_NOT_IN_PROGRESS.

Use USBTMC_BUFSIZE (4k) instead of USBTMC_SIZE_IOBUFFER (2k).
Using USBTMC_SIZE_IOBUFFER is deprecated.

Use common macro USB_CTRL_GET_TIMEOUT instead of USBTMC_TIMEOUT.

Check only bit 0 (field bmAbortBulkIn) of the
CHECK_ABORT_BULK_IN_STATUS response, since other bits are reserved
and can change in future versions.

Signed-off-by: Guido Kiener <guido.kiener@rohde-schwarz.com>
Reviewed-by: Steve Bayless <steve_bayless@keysight.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/class/usbtmc.c

@@ -270,18 +270,17 @@ static int usbtmc_release(struct inode *inode, struct file *file)
 	return 0;
 }
 
-static int usbtmc_ioctl_abort_bulk_in(struct usbtmc_device_data *data)
+static int usbtmc_ioctl_abort_bulk_in_tag(struct usbtmc_device_data *data,
+					  u8 tag)
 {
 	u8 *buffer;
 	struct device *dev;
 	int rv;
 	int n;
 	int actual;
-	struct usb_host_interface *current_setting;
-	int max_size;
 
 	dev = &data->intf->dev;
-	buffer = kmalloc(USBTMC_SIZE_IOBUFFER, GFP_KERNEL);
+	buffer = kmalloc(USBTMC_BUFSIZE, GFP_KERNEL);
 	if (!buffer)
 		return -ENOMEM;
 
@@ -289,86 +288,87 @@ static int usbtmc_ioctl_abort_bulk_in(struct usbtmc_device_data *data)
 			     usb_rcvctrlpipe(data->usb_dev, 0),
 			     USBTMC_REQUEST_INITIATE_ABORT_BULK_IN,
 			     USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_ENDPOINT,
-			     data->bTag_last_read, data->bulk_in,
-			     buffer, 2, USBTMC_TIMEOUT);
+			     tag, data->bulk_in,
+			     buffer, 2, USB_CTRL_GET_TIMEOUT);
 
 	if (rv < 0) {
 		dev_err(dev, "usb_control_msg returned %d\n", rv);
 		goto exit;
 	}
 
-	dev_dbg(dev, "INITIATE_ABORT_BULK_IN returned %x\n", buffer[0]);
+	dev_dbg(dev, "INITIATE_ABORT_BULK_IN returned %x with tag %02x\n",
+		buffer[0], buffer[1]);
 
 	if (buffer[0] == USBTMC_STATUS_FAILED) {
+		/* No transfer in progress and the Bulk-OUT FIFO is empty. */
 		rv = 0;
 		goto exit;
 	}
 
-	if (buffer[0] != USBTMC_STATUS_SUCCESS) {
-		dev_err(dev, "INITIATE_ABORT_BULK_IN returned %x\n",
-			buffer[0]);
-		rv = -EPERM;
+	if (buffer[0] == USBTMC_STATUS_TRANSFER_NOT_IN_PROGRESS) {
+		/* The device returns this status if either:
+		 * - There is a transfer in progress, but the specified bTag
+		 *   does not match.
+		 * - There is no transfer in progress, but the Bulk-OUT FIFO
+		 *   is not empty.
+		 */
+		rv = -ENOMSG;
 		goto exit;
 	}
 
-	max_size = 0;
-	current_setting = data->intf->cur_altsetting;
-	for (n = 0; n < current_setting->desc.bNumEndpoints; n++)
-		if (current_setting->endpoint[n].desc.bEndpointAddress ==
-			data->bulk_in)
-			max_size = usb_endpoint_maxp(&current_setting->endpoint[n].desc);
-
-	if (max_size == 0) {
-		dev_err(dev, "Couldn't get wMaxPacketSize\n");
+	if (buffer[0] != USBTMC_STATUS_SUCCESS) {
+		dev_err(dev, "INITIATE_ABORT_BULK_IN returned %x\n",
+			buffer[0]);
 		rv = -EPERM;
 		goto exit;
 	}
 
-	dev_dbg(&data->intf->dev, "wMaxPacketSize is %d\n", max_size);
-
 	n = 0;
 
-	do {
-		dev_dbg(dev, "Reading from bulk in EP\n");
+usbtmc_abort_bulk_in_status:
+	dev_dbg(dev, "Reading from bulk in EP\n");
 
-		rv = usb_bulk_msg(data->usb_dev,
-				  usb_rcvbulkpipe(data->usb_dev,
-						  data->bulk_in),
-				  buffer, USBTMC_SIZE_IOBUFFER,
-				  &actual, USBTMC_TIMEOUT);
+	/* Data must be present. So use low timeout 300 ms */
+	rv = usb_bulk_msg(data->usb_dev,
+			  usb_rcvbulkpipe(data->usb_dev,
+					  data->bulk_in),
+			  buffer, USBTMC_BUFSIZE,
+			  &actual, 300);
 
-		n++;
+	print_hex_dump_debug("usbtmc ", DUMP_PREFIX_NONE, 16, 1,
+			     buffer, actual, true);
 
-		if (rv < 0) {
-			dev_err(dev, "usb_bulk_msg returned %d\n", rv);
+	n++;
+
+	if (rv < 0) {
+		dev_err(dev, "usb_bulk_msg returned %d\n", rv);
+		if (rv != -ETIMEDOUT)
 			goto exit;
-		}
-	} while ((actual == max_size) &&
-		 (n < USBTMC_MAX_READS_TO_CLEAR_BULK_IN));
+	}
 
-	if (actual == max_size) {
+	if (actual == USBTMC_BUFSIZE)
+		goto usbtmc_abort_bulk_in_status;
+
+	if (n >= USBTMC_MAX_READS_TO_CLEAR_BULK_IN) {
 		dev_err(dev, "Couldn't clear device buffer within %d cycles\n",
 			USBTMC_MAX_READS_TO_CLEAR_BULK_IN);
 		rv = -EPERM;
 		goto exit;
 	}
 
-	n = 0;
-
-usbtmc_abort_bulk_in_status:
 	rv = usb_control_msg(data->usb_dev,
 			     usb_rcvctrlpipe(data->usb_dev, 0),
 			     USBTMC_REQUEST_CHECK_ABORT_BULK_IN_STATUS,
 			     USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_ENDPOINT,
 			     0, data->bulk_in, buffer, 0x08,
-			     USBTMC_TIMEOUT);
+			     USB_CTRL_GET_TIMEOUT);
 
 	if (rv < 0) {
 		dev_err(dev, "usb_control_msg returned %d\n", rv);
 		goto exit;
 	}
 
-	dev_dbg(dev, "INITIATE_ABORT_BULK_IN returned %x\n", buffer[0]);
+	dev_dbg(dev, "CHECK_ABORT_BULK_IN returned %x\n", buffer[0]);
 
 	if (buffer[0] == USBTMC_STATUS_SUCCESS) {
 		rv = 0;
@@ -376,43 +376,26 @@ usbtmc_abort_bulk_in_status:
 	}
 
 	if (buffer[0] != USBTMC_STATUS_PENDING) {
-		dev_err(dev, "INITIATE_ABORT_BULK_IN returned %x\n", buffer[0]);
+		dev_err(dev, "CHECK_ABORT_BULK_IN returned %x\n", buffer[0]);
 		rv = -EPERM;
 		goto exit;
 	}
 
-	if (buffer[1] == 1)
-		do {
-			dev_dbg(dev, "Reading from bulk in EP\n");
-
-			rv = usb_bulk_msg(data->usb_dev,
-					  usb_rcvbulkpipe(data->usb_dev,
-							  data->bulk_in),
-					  buffer, USBTMC_SIZE_IOBUFFER,
-					  &actual, USBTMC_TIMEOUT);
-
-			n++;
-
-			if (rv < 0) {
-				dev_err(dev, "usb_bulk_msg returned %d\n", rv);
-				goto exit;
-			}
-		} while ((actual == max_size) &&
-			 (n < USBTMC_MAX_READS_TO_CLEAR_BULK_IN));
-
-	if (actual == max_size) {
-		dev_err(dev, "Couldn't clear device buffer within %d cycles\n",
-			USBTMC_MAX_READS_TO_CLEAR_BULK_IN);
-		rv = -EPERM;
-		goto exit;
+	if ((buffer[1] & 1) > 0) {
+		/* The device has 1 or more queued packets the Host can read */
+		goto usbtmc_abort_bulk_in_status;
 	}
 
-	goto usbtmc_abort_bulk_in_status;
-
+	/* The Host must send CHECK_ABORT_BULK_IN_STATUS at a later time. */
+	rv = -EAGAIN;
 exit:
 	kfree(buffer);
 	return rv;
+}
 
+static int usbtmc_ioctl_abort_bulk_in(struct usbtmc_device_data *data)
+{
+	return usbtmc_ioctl_abort_bulk_in_tag(data, data->bTag_last_read);
 }
 
 static int usbtmc_ioctl_abort_bulk_out(struct usbtmc_device_data *data)