size_t bulk_in_size; /* the size of the receive buffer */
__u8 bulk_in_endpointAddr; /* the address of the bulk in endpoint */
__u8 bulk_out_endpointAddr; /* the address of the bulk out endpoint */
- struct kref kref;
+ struct kref kref;
+ struct semaphore limit_sem; /* to stop writes at full throttle from
+ * using up all RAM */
+ struct usb_anchor submitted; /* URBs to wait for before suspend */
};
#define to_lcd_dev(d) container_of(d, struct usb_lcd, kref)
+#define USB_LCD_CONCURRENT_WRITES 5
+
static struct usb_driver lcd_driver;
-static DEFINE_MUTEX(usb_lcd_open_mutex);
static void lcd_delete(struct kref *kref)
{
struct usb_lcd *dev;
struct usb_interface *interface;
- int subminor;
- int retval = 0;
+ int subminor, r;
subminor = iminor(inode);
- mutex_lock(&usb_lcd_open_mutex);
interface = usb_find_interface(&lcd_driver, subminor);
if (!interface) {
err ("USBLCD: %s - error, can't find device for minor %d",
__FUNCTION__, subminor);
- retval = -ENODEV;
- goto exit;
+ return -ENODEV;
}
dev = usb_get_intfdata(interface);
- if (!dev) {
- retval = -ENODEV;
- goto exit;
- }
+ if (!dev)
+ return -ENODEV;
/* increment our usage count for the device */
kref_get(&dev->kref);
+ /* grab a power reference */
+ r = usb_autopm_get_interface(interface);
+ if (r < 0) {
+ kref_put(&dev->kref, lcd_delete);
+ return r;
+ }
+
/* save our object in the file's private structure */
file->private_data = dev;
-exit:
- mutex_unlock(&usb_lcd_open_mutex);
- return retval;
+ return 0;
}
static int lcd_release(struct inode *inode, struct file *file)
return -ENODEV;
/* decrement the count on our device */
+ usb_autopm_put_interface(dev->interface);
kref_put(&dev->kref, lcd_delete);
return 0;
}
static void lcd_write_bulk_callback(struct urb *urb)
{
struct usb_lcd *dev;
+ int status = urb->status;
dev = (struct usb_lcd *)urb->context;
/* sync/async unlink faults aren't errors */
- if (urb->status &&
- !(urb->status == -ENOENT ||
- urb->status == -ECONNRESET ||
- urb->status == -ESHUTDOWN)) {
+ if (status &&
+ !(status == -ENOENT ||
+ status == -ECONNRESET ||
+ status == -ESHUTDOWN)) {
dbg("USBLCD: %s - nonzero write bulk status received: %d",
- __FUNCTION__, urb->status);
+ __FUNCTION__, status);
}
/* free up our allocated buffer */
usb_buffer_free(urb->dev, urb->transfer_buffer_length,
urb->transfer_buffer, urb->transfer_dma);
+ up(&dev->limit_sem);
}
static ssize_t lcd_write(struct file *file, const char __user * user_buffer, size_t count, loff_t *ppos)
{
struct usb_lcd *dev;
- int retval = 0;
+ int retval = 0, r;
struct urb *urb = NULL;
char *buf = NULL;
if (count == 0)
goto exit;
+ r = down_interruptible(&dev->limit_sem);
+ if (r < 0)
+ return -EINTR;
+
/* create a urb, and a buffer for it, and copy the data to the urb */
urb = usb_alloc_urb(0, GFP_KERNEL);
- if (!urb)
- return -ENOMEM;
+ if (!urb) {
+ retval = -ENOMEM;
+ goto err_no_buf;
+ }
buf = usb_buffer_alloc(dev->udev, count, GFP_KERNEL, &urb->transfer_dma);
if (!buf) {
usb_sndbulkpipe(dev->udev, dev->bulk_out_endpointAddr),
buf, count, lcd_write_bulk_callback, dev);
urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
+
+ usb_anchor_urb(urb, &dev->submitted);
/* send the data out the bulk port */
retval = usb_submit_urb(urb, GFP_KERNEL);
if (retval) {
err("USBLCD: %s - failed submitting write urb, error %d", __FUNCTION__, retval);
- goto error;
+ goto error_unanchor;
}
/* release our reference to this urb, the USB core will eventually free it entirely */
exit:
return count;
-
+error_unanchor:
+ usb_unanchor_urb(urb);
error:
usb_buffer_free(dev->udev, count, buf, urb->transfer_dma);
usb_free_urb(urb);
+err_no_buf:
+ up(&dev->limit_sem);
return retval;
}
goto error;
}
kref_init(&dev->kref);
+ sema_init(&dev->limit_sem, USB_LCD_CONCURRENT_WRITES);
+ init_usb_anchor(&dev->submitted);
dev->udev = usb_get_dev(interface_to_usbdev(interface));
dev->interface = interface;
return retval;
}
+static void lcd_draw_down(struct usb_lcd *dev)
+{
+ int time;
+
+ time = usb_wait_anchor_empty_timeout(&dev->submitted, 1000);
+ if (!time)
+ usb_kill_anchored_urbs(&dev->submitted);
+}
+
+static int lcd_suspend(struct usb_interface *intf, pm_message_t message)
+{
+ struct usb_lcd *dev = usb_get_intfdata(intf);
+
+ if (!dev)
+ return 0;
+ lcd_draw_down(dev);
+ return 0;
+}
+
+static int lcd_resume (struct usb_interface *intf)
+{
+ return 0;
+}
+
static void lcd_disconnect(struct usb_interface *interface)
{
struct usb_lcd *dev;
int minor = interface->minor;
- /* prevent skel_open() from racing skel_disconnect() */
- mutex_lock(&usb_lcd_open_mutex);
-
dev = usb_get_intfdata(interface);
usb_set_intfdata(interface, NULL);
/* give back our minor */
usb_deregister_dev(interface, &lcd_class);
- mutex_unlock(&usb_lcd_open_mutex);
-
/* decrement our usage count */
kref_put(&dev->kref, lcd_delete);
.name = "usblcd",
.probe = lcd_probe,
.disconnect = lcd_disconnect,
+ .suspend = lcd_suspend,
+ .resume = lcd_resume,
.id_table = id_table,
+ .supports_autosuspend = 1,
};
static int __init usb_lcd_init(void)
projects / linux-2.6 / blobdiff