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>

diff --git a/drivers/usb/class/usbtmc.c b/drivers/usb/class/usbtmc.c
index 11b2c8632d91b1519b81c75b90cb89acc86af75b..0b05aaa0247c852016a31e83c8a137a10a34c03b 100644 (file)
--- a/drivers/usb/class/usbtmc.c
+++ b/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)