diff options
Diffstat (limited to 'drivers/usb/usb-skeleton.c')
| -rw-r--r-- | drivers/usb/usb-skeleton.c | 500 |
1 files changed, 395 insertions, 105 deletions
diff --git a/drivers/usb/usb-skeleton.c b/drivers/usb/usb-skeleton.c index 5d02f16b7d0..545d09b8081 100644 --- a/drivers/usb/usb-skeleton.c +++ b/drivers/usb/usb-skeleton.c @@ -1,5 +1,5 @@ /* - * USB Skeleton driver - 2.0 + * USB Skeleton driver - 2.2 * * Copyright (C) 2001-2004 Greg Kroah-Hartman (greg@kroah.com) * @@ -7,21 +7,19 @@ * 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/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 */ @@ -29,42 +27,57 @@ #define USB_SKEL_PRODUCT_ID 0xfff0 /* table of devices that work with this driver */ -static struct usb_device_id skel_table [] = { +static const 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 */ + bool ongoing_read; /* a read is going on */ + spinlock_t err_lock; /* lock for errors */ struct kref kref; + struct mutex io_mutex; /* synchronize I/O with disconnect */ + wait_queue_head_t bulk_in_wait; /* 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) @@ -78,8 +91,8 @@ 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); + pr_err("%s - error, can't find device for minor %d\n", + __func__, subminor); retval = -ENODEV; goto exit; } @@ -90,6 +103,10 @@ static int skel_open(struct inode *inode, struct file *file) goto exit; } + retval = usb_autopm_get_interface(interface); + if (retval) + goto exit; + /* increment our usage count for the device */ kref_get(&dev->kref); @@ -104,63 +121,245 @@ static int skel_release(struct inode *inode, struct file *file) { struct usb_skel *dev; - dev = (struct usb_skel *)file->private_data; + dev = file->private_data; 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) +static int skel_flush(struct file *file, fl_owner_t id) { struct usb_skel *dev; - int retval = 0; - int bytes_read; - - 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; + int res; + + dev = file->private_data; + 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)) + dev_err(&dev->interface->dev, + "%s - nonzero write bulk status received: %d\n", + __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; + wake_up_interruptible(&dev->bulk_in_wait); +} + +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); + + /* submit bulk in urb, which means no data to deliver */ + dev->bulk_in_filled = 0; + dev->bulk_in_copied = 0; + + /* do it */ + rv = usb_submit_urb(dev->bulk_in_urb, GFP_KERNEL); + if (rv < 0) { + dev_err(&dev->interface->dev, + "%s - failed submitting read urb, error %d\n", + __func__, rv); + rv = (rv == -ENOMEM) ? rv : -EIO; + spin_lock_irq(&dev->err_lock); + dev->ongoing_read = 0; + spin_unlock_irq(&dev->err_lock); + } + + return rv; } -static void skel_write_bulk_callback(struct urb *urb, struct pt_regs *regs) +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 *)urb->context; + dev = 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_event_interruptible(dev->bulk_in_wait, (!dev->ongoing_read)); + if (rv < 0) + goto exit; + } + + /* 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; + /* 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 + goto retry; + } +exit: + mutex_unlock(&dev->io_mutex); + return rv; +} + +static void skel_write_bulk_callback(struct urb *urb) +{ + struct usb_skel *dev; + + 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)) + dev_err(&dev->interface->dev, + "%s - nonzero write bulk status received: %d\n", + __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, - urb->transfer_buffer, urb->transfer_dma); + usb_free_coherent(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; @@ -168,18 +367,40 @@ static ssize_t skel_write(struct file *file, const char *user_buffer, size_t cou char *buf = NULL; size_t writesize = min(count, (size_t)MAX_TRANSFER); - dev = (struct usb_skel *)file->private_data; + dev = file->private_data; /* verify that we actually have some data to write */ 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) { @@ -187,7 +408,8 @@ static ssize_t skel_write(struct file *file, const char *user_buffer, size_t cou goto error; } - buf = usb_buffer_alloc(dev->udev, writesize, GFP_KERNEL, &urb->transfer_dma); + buf = usb_alloc_coherent(dev->udev, writesize, GFP_KERNEL, + &urb->transfer_dma); if (!buf) { retval = -ENOMEM; goto error; @@ -198,43 +420,66 @@ static ssize_t skel_write(struct file *file, const char *user_buffer, size_t cou 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; + dev_err(&dev->interface->dev, + "%s - failed submitting write urb, error %d\n", + __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_free_coherent(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, + .llseek = noop_llseek, }; -/* +/* * 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 = "skel%d", @@ -242,9 +487,10 @@ static struct usb_class_driver skel_class = { .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; @@ -253,12 +499,16 @@ static int skel_probe(struct usb_interface *interface, const struct usb_device_i /* allocate memory for our device state and initialize it */ dev = kzalloc(sizeof(*dev), GFP_KERNEL); - if (dev == NULL) { - err("Out of memory"); + if (!dev) { + dev_err(&interface->dev, "Out of memory\n"); 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_waitqueue_head(&dev->bulk_in_wait); dev->udev = usb_get_dev(interface_to_usbdev(interface)); dev->interface = interface; @@ -270,32 +520,34 @@ static int skel_probe(struct usb_interface *interface, const struct usb_device_i 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); + buffer_size = usb_endpoint_maxp(endpoint); dev->bulk_in_size = buffer_size; dev->bulk_in_endpointAddr = endpoint->bEndpointAddress; dev->bulk_in_buffer = kmalloc(buffer_size, GFP_KERNEL); if (!dev->bulk_in_buffer) { - err("Could not allocate bulk_in_buffer"); + dev_err(&interface->dev, + "Could not allocate bulk_in_buffer\n"); + goto error; + } + dev->bulk_in_urb = usb_alloc_urb(0, GFP_KERNEL); + if (!dev->bulk_in_urb) { + dev_err(&interface->dev, + "Could not allocate bulk_in_urb\n"); 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; } } if (!(dev->bulk_in_endpointAddr && dev->bulk_out_endpointAddr)) { - err("Could not find both bulk-in and bulk-out endpoints"); + dev_err(&interface->dev, + "Could not find both bulk-in and bulk-out endpoints\n"); goto error; } @@ -306,17 +558,21 @@ static int skel_probe(struct usb_interface *interface, const struct usb_device_i retval = usb_register_dev(interface, &skel_class); if (retval) { /* something prevented us from registering this driver */ - err("Not able to get a minor for this device."); + dev_err(&interface->dev, + "Not able to get a minor for this device.\n"); usb_set_intfdata(interface, NULL); goto error; } /* 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; } @@ -326,49 +582,83 @@ static void skel_disconnect(struct usb_interface *interface) 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 struct usb_driver skel_driver = { - .name = "skeleton", - .probe = skel_probe, - .disconnect = skel_disconnect, - .id_table = skel_table, -}; +static void skel_draw_down(struct usb_skel *dev) +{ + int time; -static int __init usb_skel_init(void) + 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) { - int result; + struct usb_skel *dev = usb_get_intfdata(intf); - /* register this driver with the USB subsystem */ - result = usb_register(&skel_driver); - if (result) - err("usb_register failed. Error number %d", result); + if (!dev) + return 0; + skel_draw_down(dev); + return 0; +} - return result; +static int skel_resume(struct usb_interface *intf) +{ + return 0; } -static void __exit usb_skel_exit(void) +static int skel_pre_reset(struct usb_interface *intf) { - /* deregister this driver with the USB subsystem */ - usb_deregister(&skel_driver); + struct usb_skel *dev = usb_get_intfdata(intf); + + mutex_lock(&dev->io_mutex); + skel_draw_down(dev); + + return 0; } -module_init (usb_skel_init); -module_exit (usb_skel_exit); +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, +}; + +module_usb_driver(skel_driver); MODULE_LICENSE("GPL"); |