/*
- * USB Skeleton driver - 2.0
+ * USB Skeleton driver - 2.2
*
* Copyright (C) 2001-2004 Greg Kroah-Hartman (greg@kroah.com)
*
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation, version 2.
*
- * This driver is based on the 2.6.3 version of drivers/usb/usb-skeleton.c
- * but has been rewritten to be easy to read and use, as no locks are now
- * needed anymore.
+ * This driver is based on the 2.6.3 version of drivers/usb/usb-skeleton.c
+ * but has been rewritten to be easier to read and use.
*
*/
-#include <linux/config.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/kref.h>
#include <asm/uaccess.h>
#include <linux/usb.h>
+#include <linux/mutex.h>
/* Define these values to match your devices */
{ USB_DEVICE(USB_SKEL_VENDOR_ID, USB_SKEL_PRODUCT_ID) },
{ } /* Terminating entry */
};
-MODULE_DEVICE_TABLE (usb, skel_table);
+MODULE_DEVICE_TABLE(usb, skel_table);
/* Get a minor range for your devices from the usb maintainer */
#define USB_SKEL_MINOR_BASE 192
+/* our private defines. if this grows any larger, use your own .h file */
+#define MAX_TRANSFER (PAGE_SIZE - 512)
+#define WRITES_IN_FLIGHT 8
+
/* Structure to hold all of our device specific stuff */
struct usb_skel {
- struct usb_device * udev; /* the usb device for this device */
- struct usb_interface * interface; /* the interface for this device */
- unsigned char * bulk_in_buffer; /* the buffer to receive data */
+ struct usb_device *dev; /* the usb device for this device */
+ struct usb_interface *interface; /* the interface for this device */
+ struct semaphore limit_sem; /* limiting the number of writes in progress */
+ unsigned char *bulk_in_buffer; /* the buffer to receive data */
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 mutex io_mutex; /* synchronize I/O with disconnect */
};
#define to_skel_dev(d) container_of(d, struct usb_skel, kref)
static struct usb_driver skel_driver;
static void skel_delete(struct kref *kref)
-{
+{
struct usb_skel *dev = to_skel_dev(kref);
usb_put_dev(dev->udev);
- kfree (dev->bulk_in_buffer);
- kfree (dev);
+ kfree(dev->bulk_in_buffer);
+ kfree(dev);
}
static int skel_open(struct inode *inode, struct file *file)
goto exit;
}
+ /* prevent the device from being autosuspended */
+ retval = usb_autopm_get_interface(interface);
+ if (retval)
+ goto exit;
+
/* increment our usage count for the device */
kref_get(&dev->kref);
if (dev == NULL)
return -ENODEV;
+ /* allow the device to be autosuspended */
+ mutex_lock(&dev->io_mutex);
+ if (dev->interface)
+ usb_autopm_put_interface(dev->interface);
+ mutex_unlock(&dev->io_mutex);
+
/* decrement the count on our device */
kref_put(&dev->kref, skel_delete);
return 0;
static ssize_t skel_read(struct file *file, char *buffer, size_t count, loff_t *ppos)
{
struct usb_skel *dev;
- int retval = 0;
+ int retval;
+ int bytes_read;
dev = (struct usb_skel *)file->private_data;
-
+
+ mutex_lock(&dev->io_mutex);
+ if (!dev->interface) { /* disconnect() was called */
+ retval = -ENODEV;
+ goto exit;
+ }
+
/* do a blocking bulk read to get data from the device */
retval = usb_bulk_msg(dev->udev,
usb_rcvbulkpipe(dev->udev, dev->bulk_in_endpointAddr),
dev->bulk_in_buffer,
min(dev->bulk_in_size, count),
- &count, HZ*10);
+ &bytes_read, 10000);
/* if the read was successful, copy the data to userspace */
if (!retval) {
- if (copy_to_user(buffer, dev->bulk_in_buffer, count))
+ if (copy_to_user(buffer, dev->bulk_in_buffer, bytes_read))
retval = -EFAULT;
else
- retval = count;
+ retval = bytes_read;
}
+exit:
+ mutex_unlock(&dev->io_mutex);
return retval;
}
-static void skel_write_bulk_callback(struct urb *urb, struct pt_regs *regs)
+static void skel_write_bulk_callback(struct urb *urb)
{
struct usb_skel *dev;
dev = (struct usb_skel *)urb->context;
/* sync/async unlink faults aren't errors */
- if (urb->status &&
- !(urb->status == -ENOENT ||
+ if (urb->status &&
+ !(urb->status == -ENOENT ||
urb->status == -ECONNRESET ||
urb->status == -ESHUTDOWN)) {
- dbg("%s - nonzero write bulk status received: %d",
+ err("%s - nonzero write bulk status received: %d",
__FUNCTION__, urb->status);
}
/* free up our allocated buffer */
- usb_buffer_free(urb->dev, urb->transfer_buffer_length,
+ usb_buffer_free(urb->dev, urb->transfer_buffer_length,
urb->transfer_buffer, urb->transfer_dma);
+ up(&dev->limit_sem);
}
static ssize_t skel_write(struct file *file, const char *user_buffer, size_t count, loff_t *ppos)
int retval = 0;
struct urb *urb = NULL;
char *buf = NULL;
+ size_t writesize = min(count, (size_t)MAX_TRANSFER);
dev = (struct usb_skel *)file->private_data;
if (count == 0)
goto exit;
+ /* limit the number of URBs in flight to stop a user from using up all RAM */
+ if (down_interruptible(&dev->limit_sem)) {
+ retval = -ERESTARTSYS;
+ goto exit;
+ }
+
+ mutex_lock(&dev->io_mutex);
+ if (!dev->interface) { /* disconnect() was called */
+ retval = -ENODEV;
+ goto error;
+ }
+
/* create a urb, and a buffer for it, and copy the data to the urb */
urb = usb_alloc_urb(0, GFP_KERNEL);
if (!urb) {
goto error;
}
- buf = usb_buffer_alloc(dev->udev, count, GFP_KERNEL, &urb->transfer_dma);
+ buf = usb_buffer_alloc(dev->udev, writesize, GFP_KERNEL, &urb->transfer_dma);
if (!buf) {
retval = -ENOMEM;
goto error;
}
- if (copy_from_user(buf, user_buffer, count)) {
+ if (copy_from_user(buf, user_buffer, writesize)) {
retval = -EFAULT;
goto error;
}
/* initialize the urb properly */
usb_fill_bulk_urb(urb, dev->udev,
usb_sndbulkpipe(dev->udev, dev->bulk_out_endpointAddr),
- buf, count, skel_write_bulk_callback, dev);
+ buf, writesize, skel_write_bulk_callback, dev);
urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
/* send the data out the bulk port */
/* release our reference to this urb, the USB core will eventually free it entirely */
usb_free_urb(urb);
-exit:
- return count;
+ mutex_unlock(&dev->io_mutex);
+ return writesize;
error:
- usb_buffer_free(dev->udev, count, buf, urb->transfer_dma);
- usb_free_urb(urb);
+ if (urb) {
+ usb_buffer_free(dev->udev, writesize, buf, urb->transfer_dma);
+ usb_free_urb(urb);
+ }
+ mutex_unlock(&dev->io_mutex);
+ up(&dev->limit_sem);
+
+exit:
return retval;
}
-static struct file_operations skel_fops = {
+static const struct file_operations skel_fops = {
.owner = THIS_MODULE,
.read = skel_read,
.write = skel_write,
.release = skel_release,
};
-/*
+/*
* usb class driver info in order to get a minor number from the usb core,
- * and to have the device registered with devfs and the driver core
+ * and to have the device registered with the driver core
*/
static struct usb_class_driver skel_class = {
- .name = "usb/skel%d",
+ .name = "skel%d",
.fops = &skel_fops,
- .mode = S_IFCHR | S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH,
.minor_base = USB_SKEL_MINOR_BASE,
};
static int skel_probe(struct usb_interface *interface, const struct usb_device_id *id)
{
- struct usb_skel *dev = NULL;
+ struct usb_skel *dev;
struct usb_host_interface *iface_desc;
struct usb_endpoint_descriptor *endpoint;
size_t buffer_size;
int retval = -ENOMEM;
/* allocate memory for our device state and initialize it */
- dev = kmalloc(sizeof(*dev), GFP_KERNEL);
- if (dev == NULL) {
+ dev = kzalloc(sizeof(*dev), GFP_KERNEL);
+ if (!dev) {
err("Out of memory");
goto error;
}
- memset(dev, 0x00, sizeof(*dev));
kref_init(&dev->kref);
+ sema_init(&dev->limit_sem, WRITES_IN_FLIGHT);
+ mutex_init(&dev->io_mutex);
dev->udev = usb_get_dev(interface_to_usbdev(interface));
dev->interface = interface;
endpoint = &iface_desc->endpoint[i].desc;
if (!dev->bulk_in_endpointAddr &&
- (endpoint->bEndpointAddress & USB_DIR_IN) &&
- ((endpoint->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK)
- == USB_ENDPOINT_XFER_BULK)) {
+ usb_endpoint_is_bulk_in(endpoint)) {
/* we found a bulk in endpoint */
buffer_size = le16_to_cpu(endpoint->wMaxPacketSize);
dev->bulk_in_size = buffer_size;
}
if (!dev->bulk_out_endpointAddr &&
- !(endpoint->bEndpointAddress & USB_DIR_IN) &&
- ((endpoint->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK)
- == USB_ENDPOINT_XFER_BULK)) {
+ usb_endpoint_is_bulk_out(endpoint)) {
/* we found a bulk out endpoint */
dev->bulk_out_endpointAddr = endpoint->bEndpointAddress;
}
/* give back our minor */
usb_deregister_dev(interface, &skel_class);
+ /* prevent more I/O from starting */
+ mutex_lock(&dev->io_mutex);
+ dev->interface = NULL;
+ mutex_unlock(&dev->io_mutex);
+
unlock_kernel();
/* decrement our usage count */
}
static struct usb_driver skel_driver = {
- .owner = THIS_MODULE,
.name = "skeleton",
.probe = skel_probe,
.disconnect = skel_disconnect,
usb_deregister(&skel_driver);
}
-module_init (usb_skel_init);
-module_exit (usb_skel_exit);
+module_init(usb_skel_init);
+module_exit(usb_skel_exit);
MODULE_LICENSE("GPL");
git://git.onelab.eu / linux-2.6.git / blobdiff