staging: comedi: usbduxsigma: introduce usbduxsigma_ai_handle_urb()

Factor the urb handling and resubmit out of the analog input urb
completion handler and tidy it up. This allows a common exit path
to be used in the completion handler to stop the async command and
handle the events.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Reviewed-by: Bernd Porr <mail@berndporr.me.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/comedi/drivers/usbduxsigma.c b/drivers/staging/comedi/drivers/usbduxsigma.c
index 985c6f08c56eb17d58ce8f68eb8c36f4799da32a..1d12cc6c1ade8934db96f1248b2ad7fe7d8e31ad 100644 (file)
--- a/drivers/staging/comedi/drivers/usbduxsigma.c
+++ b/drivers/staging/comedi/drivers/usbduxsigma.c
@@ -211,23 +211,80 @@ static int usbduxsigma_ai_cancel(struct comedi_device *dev,
        return 0;
 }
 
-static void usbduxsigma_ai_urb_complete(struct urb *urb)
+static void usbduxsigma_ai_handle_urb(struct comedi_device *dev,
+                                     struct comedi_subdevice *s,
+                                     struct urb *urb)
 {
-       struct comedi_device *dev = urb->context;
        struct usbduxsigma_private *devpriv = dev->private;
-       struct comedi_subdevice *s = dev->read_subdev;
-       struct comedi_cmd *cmd = &s->async->cmd;
+       struct comedi_async *async = s->async;
+       struct comedi_cmd *cmd = &async->cmd;
        unsigned int dio_state;
        uint32_t val;
        int ret;
        int i;
 
-       /* first we test if something unusual has just happened */
+       devpriv->ai_counter--;
+       if (devpriv->ai_counter == 0) {
+               devpriv->ai_counter = devpriv->ai_timer;
+
+               if (cmd->stop_src == TRIG_COUNT) {
+                       devpriv->ai_sample_count--;
+                       if (devpriv->ai_sample_count < 0) {
+                               async->events |= COMEDI_CB_EOA;
+                               return;
+                       }
+               }
+
+               /* get the state of the dio pins to allow external trigger */
+               dio_state = be32_to_cpu(devpriv->in_buf[0]);
+
+               /* get the data from the USB bus and hand it over to comedi */
+               for (i = 0; i < cmd->chanlist_len; i++) {
+                       /* transfer data, note first byte is the DIO state */
+                       val = be32_to_cpu(devpriv->in_buf[i+1]);
+                       val &= 0x00ffffff;      /* strip status byte */
+                       val ^= 0x00800000;      /* convert to unsigned */
+
+                       if (!cfc_write_array_to_buffer(s, &val,
+                                                      sizeof(uint32_t)))
+                               return;
+               }
+       }
+
+       /* if command is still running, resubmit urb */
+       if (!(async->events & COMEDI_CB_CANCEL_MASK)) {
+               urb->dev = comedi_to_usb_dev(dev);
+               ret = usb_submit_urb(urb, GFP_ATOMIC);
+               if (ret < 0) {
+                       dev_err(dev->class_dev,
+                               "%s: urb resubmit failed (%d)\n",
+                               __func__, ret);
+                       if (ret == -EL2NSYNC)
+                               dev_err(dev->class_dev,
+                                       "buggy USB host controller or bug in IRQ handler\n");
+                       async->events |= COMEDI_CB_ERROR;
+               }
+       }
+}
+
+static void usbduxsigma_ai_urb_complete(struct urb *urb)
+{
+       struct comedi_device *dev = urb->context;
+       struct usbduxsigma_private *devpriv = dev->private;
+       struct comedi_subdevice *s = dev->read_subdev;
+       struct comedi_async *async = s->async;
+
+       /* exit if not running a command, do not resubmit urb */
+       if (!devpriv->ai_cmd_running)
+               return;
+
        switch (urb->status) {
        case 0:
                /* copy the result in the transfer buffer */
                memcpy(devpriv->in_buf, urb->transfer_buffer, SIZEINBUF);
+               usbduxsigma_ai_handle_urb(dev, s, urb);
                break;
+
        case -EILSEQ:
                /*
                 * error in the ISOchronous data
@@ -235,7 +292,7 @@ static void usbduxsigma_ai_urb_complete(struct urb *urb)
                 * and recycle the last data byte
                 */
                dev_dbg(dev->class_dev, "CRC error in ISO IN stream\n");
-
+               usbduxsigma_ai_handle_urb(dev, s, urb);
                break;
 
        case -ECONNRESET:
@@ -243,86 +300,24 @@ static void usbduxsigma_ai_urb_complete(struct urb *urb)
        case -ESHUTDOWN:
        case -ECONNABORTED:
                /* happens after an unlink command */
-               if (devpriv->ai_cmd_running) {
-                       usbduxsigma_ai_stop(dev, 0);    /* w/o unlink */
-                       /* we are still running a command, tell comedi */
-                       s->async->events |= (COMEDI_CB_EOA | COMEDI_CB_ERROR);
-                       comedi_event(dev, s);
-               }
-               return;
+               async->events |= COMEDI_CB_ERROR;
+               break;
 
        default:
-               /*
-                * a real error on the bus
-                * pass error to comedi if we are really running a command
-                */
-               if (devpriv->ai_cmd_running) {
-                       dev_err(dev->class_dev,
-                               "%s: non-zero urb status (%d)\n",
-                               __func__, urb->status);
-                       usbduxsigma_ai_stop(dev, 0);    /* w/o unlink */
-                       s->async->events |= (COMEDI_CB_EOA | COMEDI_CB_ERROR);
-                       comedi_event(dev, s);
-               }
-               return;
-       }
-
-       if (unlikely(!devpriv->ai_cmd_running))
-               return;
-
-       urb->dev = comedi_to_usb_dev(dev);
-
-       ret = usb_submit_urb(urb, GFP_ATOMIC);
-       if (unlikely(ret < 0)) {
-               dev_err(dev->class_dev, "%s: urb resubmit failed (%d)\n",
-                       __func__, ret);
-               if (ret == -EL2NSYNC)
-                       dev_err(dev->class_dev,
-                               "buggy USB host controller or bug in IRQ handler\n");
-               usbduxsigma_ai_stop(dev, 0);    /* w/o unlink */
-               s->async->events |= (COMEDI_CB_EOA | COMEDI_CB_ERROR);
-               comedi_event(dev, s);
-               return;
-       }
-
-       /* get the state of the dio pins to allow external trigger */
-       dio_state = be32_to_cpu(devpriv->in_buf[0]);
-
-       devpriv->ai_counter--;
-       if (likely(devpriv->ai_counter > 0))
-               return;
-
-       /* timer zero, transfer measurements to comedi */
-       devpriv->ai_counter = devpriv->ai_timer;
-
-       if (cmd->stop_src == TRIG_COUNT) {
-               /* not continuous, fixed number of samples */
-               devpriv->ai_sample_count--;
-               if (devpriv->ai_sample_count < 0) {
-                       usbduxsigma_ai_stop(dev, 0);    /* w/o unlink */
-                       /* acquistion is over, tell comedi */
-                       s->async->events |= COMEDI_CB_EOA;
-                       comedi_event(dev, s);
-                       return;
-               }
+               /* a real error */
+               dev_err(dev->class_dev, "%s: non-zero urb status (%d)\n",
+                       __func__, urb->status);
+               async->events |= COMEDI_CB_ERROR;
+               break;
        }
 
-       /* get the data from the USB bus and hand it over to comedi */
-       for (i = 0; i < cmd->chanlist_len; i++) {
-               /* transfer data, note first byte is the DIO state */
-               val = be32_to_cpu(devpriv->in_buf[i+1]);
-               val &= 0x00ffffff;      /* strip status byte */
-               val ^= 0x00800000;      /* convert to unsigned */
+       /*
+        * comedi_handle_events() cannot be used in this driver. The (*cancel)
+        * operation would unlink the urb.
+        */
+       if (async->events & COMEDI_CB_CANCEL_MASK)
+               usbduxsigma_ai_stop(dev, 0);
 
-               ret = cfc_write_array_to_buffer(s, &val, sizeof(uint32_t));
-               if (unlikely(ret == 0)) {
-                       /* buffer overflow */
-                       usbduxsigma_ai_stop(dev, 0);    /* w/o unlink */
-                       return;
-               }
-       }
-       /* tell comedi that data is there */
-       s->async->events |= (COMEDI_CB_BLOCK | COMEDI_CB_EOS);
        comedi_event(dev, s);
 }