/*
- * 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/slab.h>
#include <linux/module.h>
#include <linux/kref.h>
-#include <asm/uaccess.h>
+#include <linux/uaccess.h>
#include <linux/usb.h>
+#include <linux/mutex.h>
/* Define these values to match your devices */
#define USB_SKEL_PRODUCT_ID 0xfff0
/* table of devices that work with this driver */
-static struct usb_device_id skel_table [] = {
+static struct usb_device_id skel_table[] = {
{ 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 MAX_TRANSFER (PAGE_SIZE - 512)
+/* MAX_TRANSFER is chosen so that the VM is not stressed by
+ allocations > PAGE_SIZE and the number of packets in a page
+ is an integer 512 is the largest possible packet on EHCI */
#define WRITES_IN_FLIGHT 8
+/* arbitrarily chosen */
/* 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 */
+ struct usb_device *udev; /* 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 */
+ struct usb_anchor submitted; /* in case we need to retract our submissions */
+ struct urb *bulk_in_urb; /* the urb to read data with */
+ unsigned char *bulk_in_buffer; /* the buffer to receive data */
size_t bulk_in_size; /* the size of the receive buffer */
+ size_t bulk_in_filled; /* number of bytes in the buffer */
+ size_t bulk_in_copied; /* already copied to user space */
__u8 bulk_in_endpointAddr; /* the address of the bulk in endpoint */
__u8 bulk_out_endpointAddr; /* the address of the bulk out endpoint */
+ int errors; /* the last request tanked */
+ int open_count; /* count the number of openers */
+ bool ongoing_read; /* a read is going on */
+ bool processed_urb; /* indicates we haven't processed the urb */
+ spinlock_t err_lock; /* lock for errors */
struct kref kref;
+ struct mutex io_mutex; /* synchronize I/O with disconnect */
+ struct completion bulk_in_completion; /* to wait for an ongoing read */
};
#define to_skel_dev(d) container_of(d, struct usb_skel, kref)
static struct usb_driver skel_driver;
+static void skel_draw_down(struct usb_skel *dev);
static void skel_delete(struct kref *kref)
-{
+{
struct usb_skel *dev = to_skel_dev(kref);
+ usb_free_urb(dev->bulk_in_urb);
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)
interface = usb_find_interface(&skel_driver, subminor);
if (!interface) {
- err ("%s - error, can't find device for minor %d",
- __FUNCTION__, subminor);
+ err("%s - error, can't find device for minor %d",
+ __func__, subminor);
retval = -ENODEV;
goto exit;
}
/* increment our usage count for the device */
kref_get(&dev->kref);
+ /* lock the device to allow correctly handling errors
+ * in resumption */
+ mutex_lock(&dev->io_mutex);
+
+ if (!dev->open_count++) {
+ retval = usb_autopm_get_interface(interface);
+ if (retval) {
+ dev->open_count--;
+ mutex_unlock(&dev->io_mutex);
+ kref_put(&dev->kref, skel_delete);
+ goto exit;
+ }
+ } /* else { //uncomment this block if you want exclusive open
+ retval = -EBUSY;
+ dev->open_count--;
+ mutex_unlock(&dev->io_mutex);
+ kref_put(&dev->kref, skel_delete);
+ goto exit;
+ } */
+ /* prevent the device from being autosuspended */
+
/* save our object in the file's private structure */
file->private_data = dev;
+ mutex_unlock(&dev->io_mutex);
exit:
return retval;
if (dev == NULL)
return -ENODEV;
+ /* allow the device to be autosuspended */
+ mutex_lock(&dev->io_mutex);
+ if (!--dev->open_count && 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)
+static int skel_flush(struct file *file, fl_owner_t id)
{
struct usb_skel *dev;
- int retval = 0;
- int bytes_read;
+ int res;
dev = (struct usb_skel *)file->private_data;
-
- /* 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),
- &bytes_read, 10000);
-
- /* if the read was successful, copy the data to userspace */
- if (!retval) {
- if (copy_to_user(buffer, dev->bulk_in_buffer, bytes_read))
- retval = -EFAULT;
- else
- retval = bytes_read;
+ if (dev == NULL)
+ return -ENODEV;
+
+ /* wait for io to stop */
+ mutex_lock(&dev->io_mutex);
+ skel_draw_down(dev);
+
+ /* read out errors, leave subsequent opens a clean slate */
+ spin_lock_irq(&dev->err_lock);
+ res = dev->errors ? (dev->errors == -EPIPE ? -EPIPE : -EIO) : 0;
+ dev->errors = 0;
+ spin_unlock_irq(&dev->err_lock);
+
+ mutex_unlock(&dev->io_mutex);
+
+ return res;
+}
+
+static void skel_read_bulk_callback(struct urb *urb)
+{
+ struct usb_skel *dev;
+
+ dev = urb->context;
+
+ spin_lock(&dev->err_lock);
+ /* sync/async unlink faults aren't errors */
+ if (urb->status) {
+ if (!(urb->status == -ENOENT ||
+ urb->status == -ECONNRESET ||
+ urb->status == -ESHUTDOWN))
+ err("%s - nonzero write bulk status received: %d",
+ __func__, urb->status);
+
+ dev->errors = urb->status;
+ } else {
+ dev->bulk_in_filled = urb->actual_length;
}
+ dev->ongoing_read = 0;
+ spin_unlock(&dev->err_lock);
- return retval;
+ complete(&dev->bulk_in_completion);
+}
+
+static int skel_do_read_io(struct usb_skel *dev, size_t count)
+{
+ int rv;
+
+ /* prepare a read */
+ usb_fill_bulk_urb(dev->bulk_in_urb,
+ dev->udev,
+ usb_rcvbulkpipe(dev->udev,
+ dev->bulk_in_endpointAddr),
+ dev->bulk_in_buffer,
+ min(dev->bulk_in_size, count),
+ skel_read_bulk_callback,
+ dev);
+ /* tell everybody to leave the URB alone */
+ spin_lock_irq(&dev->err_lock);
+ dev->ongoing_read = 1;
+ spin_unlock_irq(&dev->err_lock);
+
+ /* do it */
+ rv = usb_submit_urb(dev->bulk_in_urb, GFP_KERNEL);
+ if (rv < 0) {
+ err("%s - failed submitting read urb, error %d",
+ __func__, rv);
+ dev->bulk_in_filled = 0;
+ rv = (rv == -ENOMEM) ? rv : -EIO;
+ spin_lock_irq(&dev->err_lock);
+ dev->ongoing_read = 0;
+ spin_unlock_irq(&dev->err_lock);
+ }
+
+ return rv;
+}
+
+static ssize_t skel_read(struct file *file, char *buffer, size_t count,
+ loff_t *ppos)
+{
+ struct usb_skel *dev;
+ int rv;
+ bool ongoing_io;
+
+ dev = (struct usb_skel *)file->private_data;
+
+ /* if we cannot read at all, return EOF */
+ if (!dev->bulk_in_urb || !count)
+ return 0;
+
+ /* no concurrent readers */
+ rv = mutex_lock_interruptible(&dev->io_mutex);
+ if (rv < 0)
+ return rv;
+
+ if (!dev->interface) { /* disconnect() was called */
+ rv = -ENODEV;
+ goto exit;
+ }
+
+ /* if IO is under way, we must not touch things */
+retry:
+ spin_lock_irq(&dev->err_lock);
+ ongoing_io = dev->ongoing_read;
+ spin_unlock_irq(&dev->err_lock);
+
+ if (ongoing_io) {
+ /* nonblocking IO shall not wait */
+ if (file->f_flags & O_NONBLOCK) {
+ rv = -EAGAIN;
+ goto exit;
+ }
+ /*
+ * IO may take forever
+ * hence wait in an interruptible state
+ */
+ rv = wait_for_completion_interruptible(&dev->bulk_in_completion);
+ if (rv < 0)
+ goto exit;
+ /*
+ * by waiting we also semiprocessed the urb
+ * we must finish now
+ */
+ dev->bulk_in_copied = 0;
+ dev->processed_urb = 1;
+ }
+
+ if (!dev->processed_urb) {
+ /*
+ * the URB hasn't been processed
+ * do it now
+ */
+ wait_for_completion(&dev->bulk_in_completion);
+ dev->bulk_in_copied = 0;
+ dev->processed_urb = 1;
+ }
+
+ /* errors must be reported */
+ rv = dev->errors;
+ if (rv < 0) {
+ /* any error is reported once */
+ dev->errors = 0;
+ /* to preserve notifications about reset */
+ rv = (rv == -EPIPE) ? rv : -EIO;
+ /* no data to deliver */
+ dev->bulk_in_filled = 0;
+ /* report it */
+ goto exit;
+ }
+
+ /*
+ * if the buffer is filled we may satisfy the read
+ * else we need to start IO
+ */
+
+ if (dev->bulk_in_filled) {
+ /* we had read data */
+ size_t available = dev->bulk_in_filled - dev->bulk_in_copied;
+ size_t chunk = min(available, count);
+
+ if (!available) {
+ /*
+ * all data has been used
+ * actual IO needs to be done
+ */
+ rv = skel_do_read_io(dev, count);
+ if (rv < 0)
+ goto exit;
+ else
+ goto retry;
+ }
+ /*
+ * data is available
+ * chunk tells us how much shall be copied
+ */
+
+ if (copy_to_user(buffer,
+ dev->bulk_in_buffer + dev->bulk_in_copied,
+ chunk))
+ rv = -EFAULT;
+ else
+ rv = chunk;
+
+ dev->bulk_in_copied += chunk;
+
+ /*
+ * if we are asked for more than we have,
+ * we start IO but don't wait
+ */
+ if (available < count)
+ skel_do_read_io(dev, count - chunk);
+ } else {
+ /* no data in the buffer */
+ rv = skel_do_read_io(dev, count);
+ if (rv < 0)
+ goto exit;
+ else if (!(file->f_flags & O_NONBLOCK))
+ goto retry;
+ rv = -EAGAIN;
+ }
+exit:
+ mutex_unlock(&dev->io_mutex);
+ return rv;
}
-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;
+ dev = urb->context;
/* sync/async unlink faults aren't errors */
- if (urb->status &&
- !(urb->status == -ENOENT ||
- urb->status == -ECONNRESET ||
- urb->status == -ESHUTDOWN)) {
- dbg("%s - nonzero write bulk status received: %d",
- __FUNCTION__, urb->status);
+ if (urb->status) {
+ if (!(urb->status == -ENOENT ||
+ urb->status == -ECONNRESET ||
+ urb->status == -ESHUTDOWN))
+ err("%s - nonzero write bulk status received: %d",
+ __func__, urb->status);
+
+ spin_lock(&dev->err_lock);
+ dev->errors = urb->status;
+ spin_unlock(&dev->err_lock);
}
/* 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)
+static ssize_t skel_write(struct file *file, const char *user_buffer,
+ size_t count, loff_t *ppos)
{
struct usb_skel *dev;
int retval = 0;
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;
+ /*
+ * limit the number of URBs in flight to stop a user from using up all
+ * RAM
+ */
+ if (!(file->f_flags & O_NONBLOCK)) {
+ if (down_interruptible(&dev->limit_sem)) {
+ retval = -ERESTARTSYS;
+ goto exit;
+ }
+ } else {
+ if (down_trylock(&dev->limit_sem)) {
+ retval = -EAGAIN;
+ goto exit;
+ }
}
+ spin_lock_irq(&dev->err_lock);
+ retval = dev->errors;
+ if (retval < 0) {
+ /* any error is reported once */
+ dev->errors = 0;
+ /* to preserve notifications about reset */
+ retval = (retval == -EPIPE) ? retval : -EIO;
+ }
+ spin_unlock_irq(&dev->err_lock);
+ if (retval < 0)
+ 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, writesize, GFP_KERNEL, &urb->transfer_dma);
+ buf = usb_buffer_alloc(dev->udev, writesize, GFP_KERNEL,
+ &urb->transfer_dma);
if (!buf) {
retval = -ENOMEM;
goto error;
goto error;
}
+ /* this lock makes sure we don't submit URBs to gone devices */
+ mutex_lock(&dev->io_mutex);
+ if (!dev->interface) { /* disconnect() was called */
+ mutex_unlock(&dev->io_mutex);
+ retval = -ENODEV;
+ goto error;
+ }
+
/* initialize the urb properly */
usb_fill_bulk_urb(urb, dev->udev,
usb_sndbulkpipe(dev->udev, dev->bulk_out_endpointAddr),
buf, writesize, skel_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);
+ mutex_unlock(&dev->io_mutex);
if (retval) {
- err("%s - failed submitting write urb, error %d", __FUNCTION__, retval);
- goto error;
+ err("%s - failed submitting write urb, error %d", __func__,
+ retval);
+ goto error_unanchor;
}
- /* release our reference to this urb, the USB core will eventually free it entirely */
+ /*
+ * release our reference to this urb, the USB core will eventually free
+ * it entirely
+ */
usb_free_urb(urb);
-exit:
+
return writesize;
+error_unanchor:
+ usb_unanchor_urb(urb);
error:
- usb_buffer_free(dev->udev, writesize, buf, urb->transfer_dma);
- usb_free_urb(urb);
+ if (urb) {
+ usb_buffer_free(dev->udev, writesize, buf, urb->transfer_dma);
+ usb_free_urb(urb);
+ }
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,
.open = skel_open,
.release = skel_release,
+ .flush = skel_flush,
};
-/*
+/*
* usb class driver info in order to get a minor number from the usb core,
* and to have the device registered with the driver core
*/
.minor_base = USB_SKEL_MINOR_BASE,
};
-static int skel_probe(struct usb_interface *interface, const struct usb_device_id *id)
+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;
/* allocate memory for our device state and initialize it */
dev = kzalloc(sizeof(*dev), GFP_KERNEL);
- if (dev == NULL) {
+ if (!dev) {
err("Out of memory");
goto error;
}
kref_init(&dev->kref);
sema_init(&dev->limit_sem, WRITES_IN_FLIGHT);
+ mutex_init(&dev->io_mutex);
+ spin_lock_init(&dev->err_lock);
+ init_usb_anchor(&dev->submitted);
+ init_completion(&dev->bulk_in_completion);
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_ENDPOINT_DIR_MASK)
- == 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;
err("Could not allocate bulk_in_buffer");
goto error;
}
+ dev->bulk_in_urb = usb_alloc_urb(0, GFP_KERNEL);
+ if (!dev->bulk_in_urb) {
+ err("Could not allocate bulk_in_urb");
+ goto error;
+ }
}
if (!dev->bulk_out_endpointAddr &&
- ((endpoint->bEndpointAddress & USB_ENDPOINT_DIR_MASK)
- == USB_DIR_OUT) &&
- ((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;
}
}
/* let the user know what node this device is now attached to */
- info("USB Skeleton device now attached to USBSkel-%d", interface->minor);
+ dev_info(&interface->dev,
+ "USB Skeleton device now attached to USBSkel-%d",
+ interface->minor);
return 0;
error:
if (dev)
+ /* this frees allocated memory */
kref_put(&dev->kref, skel_delete);
return retval;
}
struct usb_skel *dev;
int minor = interface->minor;
- /* prevent skel_open() from racing skel_disconnect() */
- lock_kernel();
-
dev = usb_get_intfdata(interface);
usb_set_intfdata(interface, NULL);
/* give back our minor */
usb_deregister_dev(interface, &skel_class);
- unlock_kernel();
+ /* prevent more I/O from starting */
+ mutex_lock(&dev->io_mutex);
+ dev->interface = NULL;
+ mutex_unlock(&dev->io_mutex);
+
+ usb_kill_anchored_urbs(&dev->submitted);
/* decrement our usage count */
kref_put(&dev->kref, skel_delete);
- info("USB Skeleton #%d now disconnected", minor);
+ dev_info(&interface->dev, "USB Skeleton #%d now disconnected", minor);
+}
+
+static void skel_draw_down(struct usb_skel *dev)
+{
+ int time;
+
+ time = usb_wait_anchor_empty_timeout(&dev->submitted, 1000);
+ if (!time)
+ usb_kill_anchored_urbs(&dev->submitted);
+ usb_kill_urb(dev->bulk_in_urb);
+}
+
+static int skel_suspend(struct usb_interface *intf, pm_message_t message)
+{
+ struct usb_skel *dev = usb_get_intfdata(intf);
+
+ if (!dev)
+ return 0;
+ skel_draw_down(dev);
+ return 0;
+}
+
+static int skel_resume(struct usb_interface *intf)
+{
+ return 0;
+}
+
+static int skel_pre_reset(struct usb_interface *intf)
+{
+ struct usb_skel *dev = usb_get_intfdata(intf);
+
+ mutex_lock(&dev->io_mutex);
+ skel_draw_down(dev);
+
+ return 0;
+}
+
+static int skel_post_reset(struct usb_interface *intf)
+{
+ struct usb_skel *dev = usb_get_intfdata(intf);
+
+ /* we are sure no URBs are active - no locking needed */
+ dev->errors = -EPIPE;
+ mutex_unlock(&dev->io_mutex);
+
+ return 0;
}
static struct usb_driver skel_driver = {
.name = "skeleton",
.probe = skel_probe,
.disconnect = skel_disconnect,
+ .suspend = skel_suspend,
+ .resume = skel_resume,
+ .pre_reset = skel_pre_reset,
+ .post_reset = skel_post_reset,
.id_table = skel_table,
+ .supports_autosuspend = 1,
};
static int __init usb_skel_init(void)
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://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff