/**
* usb_alphatrack_read
*/
static ssize_t usb_alphatrack_read(struct file *file, char __user *buffer, size_t count,
loff_t *ppos)
{
struct usb_alphatrack *dev;
int retval = 0;
int c = 0;
dev = file->private_data;
/* verify that we actually have some data to read */
if (count == 0)
goto exit;
/* lock this object */
if (down_interruptible(&dev->sem)) {
retval = -ERESTARTSYS;
goto exit;
}
/* verify that the device wasn't unplugged */
if (dev->intf == NULL) {
retval = -ENODEV;
err("No device or device unplugged %d\n", retval);
goto unlock_exit;
}
while (dev->ring_head == dev->ring_tail) {
if (file->f_flags & O_NONBLOCK) {
retval = -EAGAIN;
goto unlock_exit;
}
dev->interrupt_in_done = 0 ;
retval = wait_event_interruptible(dev->read_wait, dev->interrupt_in_done);
if (retval < 0) {
goto unlock_exit;
}
}
alphatrack_ocmd_info(&dev->intf->dev, &(*dev->ring_buffer)[dev->ring_tail].cmd, "%s", ": copying to userspace");
c = 0;
while((c < count) && (dev->ring_tail != dev->ring_head)) {
if (copy_to_user(&buffer[c], &(*dev->ring_buffer)[dev->ring_tail], INPUT_CMD_SIZE)) {
retval = -EFAULT;
goto unlock_exit;
}
dev->ring_tail = (dev->ring_tail+1) % ring_buffer_size;
c+=INPUT_CMD_SIZE;
dbg_info(&dev->intf->dev, "%s: head, tail are %x, %x\n", __func__,dev->ring_head,dev->ring_tail);
}
retval = c;
unlock_exit:
/* unlock the device */
up(&dev->sem);
exit:
return retval;
}
static void usb_alphatrack_interrupt_in_callback(struct urb *urb)
{
struct usb_alphatrack *dev = urb->context;
unsigned int next_ring_head;
int retval = -1;
if (urb->status) {
if (urb->status == -ENOENT ||
urb->status == -ECONNRESET || urb->status == -ESHUTDOWN) {
goto exit;
} else {
dbg_info(&dev->intf->dev,
"%s: nonzero status received: %d\n", __func__,
urb->status);
goto resubmit; /* maybe we can recover */
}
}
if (urb->actual_length != INPUT_CMD_SIZE) {
dev_warn(&dev->intf->dev,
"Urb length was %d bytes!!"
"Do something intelligent \n", urb->actual_length);
} else {
alphatrack_ocmd_info(&dev->intf->dev,
&(*dev->ring_buffer)[dev->ring_tail].cmd,
"%s", "bla");
if (memcmp
(dev->interrupt_in_buffer, dev->oldi_buffer,
INPUT_CMD_SIZE) == 0) {
goto resubmit;
}
memcpy(dev->oldi_buffer, dev->interrupt_in_buffer,
INPUT_CMD_SIZE);
#if SUPPRESS_EXTRA_OFFLINE_EVENTS
if (dev->offline == 2 && dev->interrupt_in_buffer[1] == 0xff)
goto resubmit;
if (dev->offline == 1 && dev->interrupt_in_buffer[1] == 0xff) {
dev->offline = 2;
goto resubmit;
}
/* Always pass one offline event up the stack */
if (dev->offline > 0 && dev->interrupt_in_buffer[1] != 0xff)
dev->offline = 0;
if (dev->offline == 0 && dev->interrupt_in_buffer[1] == 0xff)
dev->offline = 1;
#endif
dbg_info(&dev->intf->dev, "%s: head, tail are %x, %x\n",
__func__, dev->ring_head, dev->ring_tail);
next_ring_head = (dev->ring_head + 1) % ring_buffer_size;
if (next_ring_head != dev->ring_tail) {
memcpy(&((*dev->ring_buffer)[dev->ring_head]),
dev->interrupt_in_buffer, urb->actual_length);
dev->ring_head = next_ring_head;
retval = 0;
memset(dev->interrupt_in_buffer, 0, urb->actual_length);
} else {
dev_warn(&dev->intf->dev,
"Ring buffer overflow, %d bytes dropped\n",
urb->actual_length);
memset(dev->interrupt_in_buffer, 0, urb->actual_length);
}
}
resubmit:
/* resubmit if we're still running */
if (dev->interrupt_in_running && dev->intf) {
retval = usb_submit_urb(dev->interrupt_in_urb, GFP_ATOMIC);
if (retval)
dev_err(&dev->intf->dev,
"usb_submit_urb failed (%d)\n", retval);
}
exit:
dev->interrupt_in_done = 1;
wake_up_interruptible(&dev->read_wait);
}