diff options
Diffstat (limited to 'drivers/usb/class/cdc-wdm.c')
| -rw-r--r-- | drivers/usb/class/cdc-wdm.c | 1209 |
1 files changed, 1209 insertions, 0 deletions
diff --git a/drivers/usb/class/cdc-wdm.c b/drivers/usb/class/cdc-wdm.c new file mode 100644 index 0000000..8fda45a --- /dev/null +++ b/drivers/usb/class/cdc-wdm.c @@ -0,0 +1,1209 @@ +/* + * cdc-wdm.c + * + * This driver supports USB CDC WCM Device Management. + * + * Copyright (c) 2007-2009 Oliver Neukum + * + * Some code taken from cdc-acm.c + * + * Released under the GPLv2. + * + * Many thanks to Carl Nordbeck + */ +#include <linux/kernel.h> +#include <linux/errno.h> +#include <linux/ioctl.h> +#include <linux/slab.h> +#include <linux/module.h> +#include <linux/mutex.h> +#include <linux/uaccess.h> +#include <linux/bitops.h> +#include <linux/poll.h> +#include <linux/usb.h> +#include <linux/usb/cdc.h> +#include <asm/byteorder.h> +#include <asm/unaligned.h> +#include <linux/usb/cdc-wdm.h> + +/* + * Version Information + */ +#define DRIVER_VERSION "v0.03" +#define DRIVER_AUTHOR "Oliver Neukum" +#define DRIVER_DESC "USB Abstract Control Model driver for USB WCM Device Management" + +static const struct usb_device_id wdm_ids[] = { + { + .match_flags = USB_DEVICE_ID_MATCH_INT_CLASS | + USB_DEVICE_ID_MATCH_INT_SUBCLASS, + .bInterfaceClass = USB_CLASS_COMM, + .bInterfaceSubClass = USB_CDC_SUBCLASS_DMM + }, + { } +}; + +MODULE_DEVICE_TABLE (usb, wdm_ids); + +#define WDM_MINOR_BASE 176 + + +#define WDM_IN_USE 1 +#define WDM_DISCONNECTING 2 +#define WDM_RESULT 3 +#define WDM_READ 4 +#define WDM_INT_STALL 5 +#define WDM_POLL_RUNNING 6 +#define WDM_RESPONDING 7 +#define WDM_SUSPENDING 8 +#define WDM_RESETTING 9 +#define WDM_OVERFLOW 10 +#define WDM_DRAIN_ON_OPEN 11 + +#define WDM_MAX 16 + +/* CDC-WMC r1.1 requires wMaxCommand to be "at least 256 decimal (0x100)" */ +#define WDM_DEFAULT_BUFSIZE 256 + +static DEFINE_MUTEX(wdm_mutex); +static DEFINE_SPINLOCK(wdm_device_list_lock); +static LIST_HEAD(wdm_device_list); + +/* --- method tables --- */ + +struct wdm_device { + u8 *inbuf; /* buffer for response */ + u8 *outbuf; /* buffer for command */ + u8 *sbuf; /* buffer for status */ + u8 *ubuf; /* buffer for copy to user space */ + + struct urb *command; + struct urb *response; + struct urb *validity; + struct usb_interface *intf; + struct usb_ctrlrequest *orq; + struct usb_ctrlrequest *irq; + spinlock_t iuspin; + + unsigned long flags; + u16 bufsize; + u16 wMaxCommand; + u16 wMaxPacketSize; + __le16 inum; + int reslength; + int length; + int read; + int count; + dma_addr_t shandle; + dma_addr_t ihandle; + struct mutex wlock; + struct mutex rlock; + wait_queue_head_t wait; + struct work_struct rxwork; + int werr; + int rerr; + int resp_count; + + struct list_head device_list; + int (*manage_power)(struct usb_interface *, int); +}; + +static struct usb_driver wdm_driver; + +/* return intfdata if we own the interface, else look up intf in the list */ +static struct wdm_device *wdm_find_device(struct usb_interface *intf) +{ + struct wdm_device *desc; + + spin_lock(&wdm_device_list_lock); + list_for_each_entry(desc, &wdm_device_list, device_list) + if (desc->intf == intf) + goto found; + desc = NULL; +found: + spin_unlock(&wdm_device_list_lock); + + return desc; +} + +static struct wdm_device *wdm_find_device_by_minor(int minor) +{ + struct wdm_device *desc; + + spin_lock(&wdm_device_list_lock); + list_for_each_entry(desc, &wdm_device_list, device_list) + if (desc->intf->minor == minor) + goto found; + desc = NULL; +found: + spin_unlock(&wdm_device_list_lock); + + return desc; +} + +/* --- callbacks --- */ +static void wdm_out_callback(struct urb *urb) +{ + struct wdm_device *desc; + desc = urb->context; + spin_lock(&desc->iuspin); + desc->werr = urb->status; + spin_unlock(&desc->iuspin); + kfree(desc->outbuf); + desc->outbuf = NULL; + clear_bit(WDM_IN_USE, &desc->flags); + wake_up(&desc->wait); +} + +/* forward declaration */ +static int service_outstanding_interrupt(struct wdm_device *desc); + +static void wdm_in_callback(struct urb *urb) +{ + struct wdm_device *desc = urb->context; + int status = urb->status; + int length = urb->actual_length; + + spin_lock(&desc->iuspin); + clear_bit(WDM_RESPONDING, &desc->flags); + + if (status) { + switch (status) { + case -ENOENT: + dev_dbg(&desc->intf->dev, + "nonzero urb status received: -ENOENT\n"); + goto skip_error; + case -ECONNRESET: + dev_dbg(&desc->intf->dev, + "nonzero urb status received: -ECONNRESET\n"); + goto skip_error; + case -ESHUTDOWN: + dev_dbg(&desc->intf->dev, + "nonzero urb status received: -ESHUTDOWN\n"); + goto skip_error; + case -EPIPE: + dev_dbg(&desc->intf->dev, + "nonzero urb status received: -EPIPE\n"); + break; + default: + dev_err(&desc->intf->dev, + "Unexpected error %d\n", status); + break; + } + } + + /* + * only set a new error if there is no previous error. + * Errors are only cleared during read/open + */ + if (desc->rerr == 0) + desc->rerr = status; + + if (length + desc->length > desc->wMaxCommand) { + /* The buffer would overflow */ + set_bit(WDM_OVERFLOW, &desc->flags); + } else { + /* we may already be in overflow */ + if (!test_bit(WDM_OVERFLOW, &desc->flags)) { + memmove(desc->ubuf + desc->length, desc->inbuf, length); + desc->length += length; + desc->reslength = length; + } + } + + /* + * Handling devices with the WDM_DRAIN_ON_OPEN flag set: + * If desc->resp_count is unset, then the urb was submitted + * without a prior notification. If the device returned any + * data, then this implies that it had messages queued without + * notifying us. Continue reading until that queue is flushed. + */ + if (!desc->resp_count) { + if (!length) { + /* do not propagate the expected -EPIPE */ + desc->rerr = 0; + goto unlock; + } + dev_dbg(&desc->intf->dev, "got %d bytes without notification\n", length); + set_bit(WDM_RESPONDING, &desc->flags); + usb_submit_urb(desc->response, GFP_ATOMIC); + } + +skip_error: + set_bit(WDM_READ, &desc->flags); + wake_up(&desc->wait); + + if (desc->rerr) { + /* + * Since there was an error, userspace may decide to not read + * any data after poll'ing. + * We should respond to further attempts from the device to send + * data, so that we can get unstuck. + */ + service_outstanding_interrupt(desc); + } + +unlock: + spin_unlock(&desc->iuspin); +} + +static void wdm_int_callback(struct urb *urb) +{ + int rv = 0; + int responding; + int status = urb->status; + struct wdm_device *desc; + struct usb_cdc_notification *dr; + + desc = urb->context; + dr = (struct usb_cdc_notification *)desc->sbuf; + + if (status) { + switch (status) { + case -ESHUTDOWN: + case -ENOENT: + case -ECONNRESET: + return; /* unplug */ + case -EPIPE: + set_bit(WDM_INT_STALL, &desc->flags); + dev_err(&desc->intf->dev, "Stall on int endpoint\n"); + goto sw; /* halt is cleared in work */ + default: + dev_err(&desc->intf->dev, + "nonzero urb status received: %d\n", status); + break; + } + } + + if (urb->actual_length < sizeof(struct usb_cdc_notification)) { + dev_err(&desc->intf->dev, "wdm_int_callback - %d bytes\n", + urb->actual_length); + goto exit; + } + + switch (dr->bNotificationType) { + case USB_CDC_NOTIFY_RESPONSE_AVAILABLE: + dev_dbg(&desc->intf->dev, + "NOTIFY_RESPONSE_AVAILABLE received: index %d len %d\n", + le16_to_cpu(dr->wIndex), le16_to_cpu(dr->wLength)); + break; + + case USB_CDC_NOTIFY_NETWORK_CONNECTION: + + dev_dbg(&desc->intf->dev, + "NOTIFY_NETWORK_CONNECTION %s network\n", + dr->wValue ? "connected to" : "disconnected from"); + goto exit; + case USB_CDC_NOTIFY_SPEED_CHANGE: + dev_dbg(&desc->intf->dev, "SPEED_CHANGE received (len %u)\n", + urb->actual_length); + goto exit; + default: + clear_bit(WDM_POLL_RUNNING, &desc->flags); + dev_err(&desc->intf->dev, + "unknown notification %d received: index %d len %d\n", + dr->bNotificationType, + le16_to_cpu(dr->wIndex), + le16_to_cpu(dr->wLength)); + goto exit; + } + + spin_lock(&desc->iuspin); + responding = test_and_set_bit(WDM_RESPONDING, &desc->flags); + if (!desc->resp_count++ && !responding + && !test_bit(WDM_DISCONNECTING, &desc->flags) + && !test_bit(WDM_SUSPENDING, &desc->flags)) { + rv = usb_submit_urb(desc->response, GFP_ATOMIC); + dev_dbg(&desc->intf->dev, "submit response URB %d\n", rv); + } + spin_unlock(&desc->iuspin); + if (rv < 0) { + clear_bit(WDM_RESPONDING, &desc->flags); + if (rv == -EPERM) + return; + if (rv == -ENOMEM) { +sw: + rv = schedule_work(&desc->rxwork); + if (rv) + dev_err(&desc->intf->dev, + "Cannot schedule work\n"); + } + } +exit: + rv = usb_submit_urb(urb, GFP_ATOMIC); + if (rv) + dev_err(&desc->intf->dev, + "%s - usb_submit_urb failed with result %d\n", + __func__, rv); + +} + +static void kill_urbs(struct wdm_device *desc) +{ + /* the order here is essential */ + usb_kill_urb(desc->command); + usb_kill_urb(desc->validity); + usb_kill_urb(desc->response); +} + +static void free_urbs(struct wdm_device *desc) +{ + usb_free_urb(desc->validity); + usb_free_urb(desc->response); + usb_free_urb(desc->command); +} + +static void cleanup(struct wdm_device *desc) +{ + kfree(desc->sbuf); + kfree(desc->inbuf); + kfree(desc->orq); + kfree(desc->irq); + kfree(desc->ubuf); + free_urbs(desc); + kfree(desc); +} + +static ssize_t wdm_write +(struct file *file, const char __user *buffer, size_t count, loff_t *ppos) +{ + u8 *buf; + int rv = -EMSGSIZE, r, we; + struct wdm_device *desc = file->private_data; + struct usb_ctrlrequest *req; + + if (count > desc->wMaxCommand) + count = desc->wMaxCommand; + + spin_lock_irq(&desc->iuspin); + we = desc->werr; + desc->werr = 0; + spin_unlock_irq(&desc->iuspin); + if (we < 0) + return usb_translate_errors(we); + + buf = kmalloc(count, GFP_KERNEL); + if (!buf) { + rv = -ENOMEM; + goto outnl; + } + + r = copy_from_user(buf, buffer, count); + if (r > 0) { + rv = -EFAULT; + goto out_free_mem; + } + + /* concurrent writes and disconnect */ + r = mutex_lock_interruptible(&desc->wlock); + rv = -ERESTARTSYS; + if (r) + goto out_free_mem; + + if (test_bit(WDM_DISCONNECTING, &desc->flags)) { + rv = -ENODEV; + goto out_free_mem_lock; + } + + r = usb_autopm_get_interface(desc->intf); + if (r < 0) { + rv = usb_translate_errors(r); + goto out_free_mem_lock; + } + + if (!(file->f_flags & O_NONBLOCK)) + r = wait_event_interruptible(desc->wait, !test_bit(WDM_IN_USE, + &desc->flags)); + else + if (test_bit(WDM_IN_USE, &desc->flags)) + r = -EAGAIN; + + if (test_bit(WDM_RESETTING, &desc->flags)) + r = -EIO; + + if (r < 0) { + rv = r; + goto out_free_mem_pm; + } + + req = desc->orq; + usb_fill_control_urb( + desc->command, + interface_to_usbdev(desc->intf), + /* using common endpoint 0 */ + usb_sndctrlpipe(interface_to_usbdev(desc->intf), 0), + (unsigned char *)req, + buf, + count, + wdm_out_callback, + desc + ); + + req->bRequestType = (USB_DIR_OUT | USB_TYPE_CLASS | + USB_RECIP_INTERFACE); + req->bRequest = USB_CDC_SEND_ENCAPSULATED_COMMAND; + req->wValue = 0; + req->wIndex = desc->inum; /* already converted */ + req->wLength = cpu_to_le16(count); + set_bit(WDM_IN_USE, &desc->flags); + desc->outbuf = buf; + + rv = usb_submit_urb(desc->command, GFP_KERNEL); + if (rv < 0) { + desc->outbuf = NULL; + clear_bit(WDM_IN_USE, &desc->flags); + dev_err(&desc->intf->dev, "Tx URB error: %d\n", rv); + rv = usb_translate_errors(rv); + goto out_free_mem_pm; + } else { + dev_dbg(&desc->intf->dev, "Tx URB has been submitted index=%d\n", + le16_to_cpu(req->wIndex)); + } + + usb_autopm_put_interface(desc->intf); + mutex_unlock(&desc->wlock); +outnl: + return rv < 0 ? rv : count; + +out_free_mem_pm: + usb_autopm_put_interface(desc->intf); +out_free_mem_lock: + mutex_unlock(&desc->wlock); +out_free_mem: + kfree(buf); + return rv; +} + +/* + * Submit the read urb if resp_count is non-zero. + * + * Called with desc->iuspin locked + */ +static int service_outstanding_interrupt(struct wdm_device *desc) +{ + int rv = 0; + + /* submit read urb only if the device is waiting for it */ + if (!desc->resp_count || !--desc->resp_count) + goto out; + + set_bit(WDM_RESPONDING, &desc->flags); + spin_unlock_irq(&desc->iuspin); + rv = usb_submit_urb(desc->response, GFP_KERNEL); + spin_lock_irq(&desc->iuspin); + if (rv) { + dev_err(&desc->intf->dev, + "usb_submit_urb failed with result %d\n", rv); + + /* make sure the next notification trigger a submit */ + clear_bit(WDM_RESPONDING, &desc->flags); + desc->resp_count = 0; + } +out: + return rv; +} + +static ssize_t wdm_read +(struct file *file, char __user *buffer, size_t count, loff_t *ppos) +{ + int rv, cntr; + int i = 0; + struct wdm_device *desc = file->private_data; + + + rv = mutex_lock_interruptible(&desc->rlock); /*concurrent reads */ + if (rv < 0) + return -ERESTARTSYS; + + cntr = ACCESS_ONCE(desc->length); + if (cntr == 0) { + desc->read = 0; +retry: + if (test_bit(WDM_DISCONNECTING, &desc->flags)) { + rv = -ENODEV; + goto err; + } + if (test_bit(WDM_OVERFLOW, &desc->flags)) { + clear_bit(WDM_OVERFLOW, &desc->flags); + rv = -ENOBUFS; + goto err; + } + i++; + if (file->f_flags & O_NONBLOCK) { + if (!test_bit(WDM_READ, &desc->flags)) { + rv = -EAGAIN; + goto err; + } + rv = 0; + } else { + rv = wait_event_interruptible(desc->wait, + test_bit(WDM_READ, &desc->flags)); + } + + /* may have happened while we slept */ + if (test_bit(WDM_DISCONNECTING, &desc->flags)) { + rv = -ENODEV; + goto err; + } + if (test_bit(WDM_RESETTING, &desc->flags)) { + rv = -EIO; + goto err; + } + usb_mark_last_busy(interface_to_usbdev(desc->intf)); + if (rv < 0) { + rv = -ERESTARTSYS; + goto err; + } + + spin_lock_irq(&desc->iuspin); + + if (desc->rerr) { /* read completed, error happened */ + rv = usb_translate_errors(desc->rerr); + desc->rerr = 0; + spin_unlock_irq(&desc->iuspin); + goto err; + } + /* + * recheck whether we've lost the race + * against the completion handler + */ + if (!test_bit(WDM_READ, &desc->flags)) { /* lost race */ + spin_unlock_irq(&desc->iuspin); + goto retry; + } + + if (!desc->reslength) { /* zero length read */ + dev_dbg(&desc->intf->dev, "zero length - clearing WDM_READ\n"); + clear_bit(WDM_READ, &desc->flags); + rv = service_outstanding_interrupt(desc); + spin_unlock_irq(&desc->iuspin); + if (rv < 0) + goto err; + goto retry; + } + cntr = desc->length; + spin_unlock_irq(&desc->iuspin); + } + + if (cntr > count) + cntr = count; + rv = copy_to_user(buffer, desc->ubuf, cntr); + if (rv > 0) { + rv = -EFAULT; + goto err; + } + + spin_lock_irq(&desc->iuspin); + + for (i = 0; i < desc->length - cntr; i++) + desc->ubuf[i] = desc->ubuf[i + cntr]; + + desc->length -= cntr; + /* in case we had outstanding data */ + if (!desc->length) { + clear_bit(WDM_READ, &desc->flags); + service_outstanding_interrupt(desc); + } + spin_unlock_irq(&desc->iuspin); + rv = cntr; + +err: + mutex_unlock(&desc->rlock); + return rv; +} + +static int wdm_flush(struct file *file, fl_owner_t id) +{ + struct wdm_device *desc = file->private_data; + + wait_event(desc->wait, !test_bit(WDM_IN_USE, &desc->flags)); + + /* cannot dereference desc->intf if WDM_DISCONNECTING */ + if (desc->werr < 0 && !test_bit(WDM_DISCONNECTING, &desc->flags)) + dev_err(&desc->intf->dev, "Error in flush path: %d\n", + desc->werr); + + return usb_translate_errors(desc->werr); +} + +static unsigned int wdm_poll(struct file *file, struct poll_table_struct *wait) +{ + struct wdm_device *desc = file->private_data; + unsigned long flags; + unsigned int mask = 0; + + spin_lock_irqsave(&desc->iuspin, flags); + if (test_bit(WDM_DISCONNECTING, &desc->flags)) { + mask = POLLHUP | POLLERR; + spin_unlock_irqrestore(&desc->iuspin, flags); + goto desc_out; + } + if (test_bit(WDM_READ, &desc->flags)) + mask = POLLIN | POLLRDNORM; + if (desc->rerr || desc->werr) + mask |= POLLERR; + if (!test_bit(WDM_IN_USE, &desc->flags)) + mask |= POLLOUT | POLLWRNORM; + spin_unlock_irqrestore(&desc->iuspin, flags); + + poll_wait(file, &desc->wait, wait); + +desc_out: + return mask; +} + +static int wdm_open(struct inode *inode, struct file *file) +{ + int minor = iminor(inode); + int rv = -ENODEV; + struct usb_interface *intf; + struct wdm_device *desc; + + mutex_lock(&wdm_mutex); + desc = wdm_find_device_by_minor(minor); + if (!desc) + goto out; + + intf = desc->intf; + if (test_bit(WDM_DISCONNECTING, &desc->flags)) + goto out; + file->private_data = desc; + + rv = usb_autopm_get_interface(desc->intf); + if (rv < 0) { + dev_err(&desc->intf->dev, "Error autopm - %d\n", rv); + goto out; + } + + /* using write lock to protect desc->count */ + mutex_lock(&desc->wlock); + if (!desc->count++) { + desc->werr = 0; + desc->rerr = 0; + rv = usb_submit_urb(desc->validity, GFP_KERNEL); + if (rv < 0) { + desc->count--; + dev_err(&desc->intf->dev, + "Error submitting int urb - %d\n", rv); + rv = usb_translate_errors(rv); + } else if (test_bit(WDM_DRAIN_ON_OPEN, &desc->flags)) { + /* + * Some devices keep pending messages queued + * without resending notifications. We must + * flush the message queue before we can + * assume a one-to-one relationship between + * notifications and messages in the queue + */ + dev_dbg(&desc->intf->dev, "draining queued data\n"); + set_bit(WDM_RESPONDING, &desc->flags); + rv = usb_submit_urb(desc->response, GFP_KERNEL); + } + } else { + rv = 0; + } + mutex_unlock(&desc->wlock); + if (desc->count == 1) + desc->manage_power(intf, 1); + usb_autopm_put_interface(desc->intf); +out: + mutex_unlock(&wdm_mutex); + return rv; +} + +static int wdm_release(struct inode *inode, struct file *file) +{ + struct wdm_device *desc = file->private_data; + + mutex_lock(&wdm_mutex); + + /* using write lock to protect desc->count */ + mutex_lock(&desc->wlock); + desc->count--; + mutex_unlock(&desc->wlock); + + if (!desc->count) { + if (!test_bit(WDM_DISCONNECTING, &desc->flags)) { + dev_dbg(&desc->intf->dev, "wdm_release: cleanup\n"); + kill_urbs(desc); + spin_lock_irq(&desc->iuspin); + desc->resp_count = 0; + spin_unlock_irq(&desc->iuspin); + desc->manage_power(desc->intf, 0); + } else { + /* must avoid dev_printk here as desc->intf is invalid */ + pr_debug(KBUILD_MODNAME " %s: device gone - cleaning up\n", __func__); + cleanup(desc); + } + } + mutex_unlock(&wdm_mutex); + return 0; +} + +static long wdm_ioctl(struct file *file, unsigned int cmd, unsigned long arg) +{ + struct wdm_device *desc = file->private_data; + int rv = 0; + + switch (cmd) { + case IOCTL_WDM_MAX_COMMAND: + if (copy_to_user((void __user *)arg, &desc->wMaxCommand, sizeof(desc->wMaxCommand))) + rv = -EFAULT; + break; + default: + rv = -ENOTTY; + } + return rv; +} + +static const struct file_operations wdm_fops = { + .owner = THIS_MODULE, + .read = wdm_read, + .write = wdm_write, + .open = wdm_open, + .flush = wdm_flush, + .release = wdm_release, + .poll = wdm_poll, + .unlocked_ioctl = wdm_ioctl, + .compat_ioctl = wdm_ioctl, + .llseek = noop_llseek, +}; + +static struct usb_class_driver wdm_class = { + .name = "cdc-wdm%d", + .fops = &wdm_fops, + .minor_base = WDM_MINOR_BASE, +}; + +/* --- error handling --- */ +static void wdm_rxwork(struct work_struct *work) +{ + struct wdm_device *desc = container_of(work, struct wdm_device, rxwork); + unsigned long flags; + int rv = 0; + int responding; + + spin_lock_irqsave(&desc->iuspin, flags); + if (test_bit(WDM_DISCONNECTING, &desc->flags)) { + spin_unlock_irqrestore(&desc->iuspin, flags); + } else { + responding = test_and_set_bit(WDM_RESPONDING, &desc->flags); + spin_unlock_irqrestore(&desc->iuspin, flags); + if (!responding) + rv = usb_submit_urb(desc->response, GFP_KERNEL); + if (rv < 0 && rv != -EPERM) { + spin_lock_irqsave(&desc->iuspin, flags); + clear_bit(WDM_RESPONDING, &desc->flags); + if (!test_bit(WDM_DISCONNECTING, &desc->flags)) + schedule_work(&desc->rxwork); + spin_unlock_irqrestore(&desc->iuspin, flags); + } + } +} + +/* --- hotplug --- */ + +static int wdm_create(struct usb_interface *intf, struct usb_endpoint_descriptor *ep, + u16 bufsize, int (*manage_power)(struct usb_interface *, int), + bool drain_on_open) +{ + int rv = -ENOMEM; + struct wdm_device *desc; + + desc = kzalloc(sizeof(struct wdm_device), GFP_KERNEL); + if (!desc) + goto out; + INIT_LIST_HEAD(&desc->device_list); + mutex_init(&desc->rlock); + mutex_init(&desc->wlock); + spin_lock_init(&desc->iuspin); + init_waitqueue_head(&desc->wait); + desc->wMaxCommand = bufsize; + /* this will be expanded and needed in hardware endianness */ + desc->inum = cpu_to_le16((u16)intf->cur_altsetting->desc.bInterfaceNumber); + desc->intf = intf; + INIT_WORK(&desc->rxwork, wdm_rxwork); + + rv = -EINVAL; + if (!usb_endpoint_is_int_in(ep)) + goto err; + + desc->wMaxPacketSize = usb_endpoint_maxp(ep); + + desc->orq = kmalloc(sizeof(struct usb_ctrlrequest), GFP_KERNEL); + if (!desc->orq) + goto err; + desc->irq = kmalloc(sizeof(struct usb_ctrlrequest), GFP_KERNEL); + if (!desc->irq) + goto err; + + desc->validity = usb_alloc_urb(0, GFP_KERNEL); + if (!desc->validity) + goto err; + + desc->response = usb_alloc_urb(0, GFP_KERNEL); + if (!desc->response) + goto err; + + desc->command = usb_alloc_urb(0, GFP_KERNEL); + if (!desc->command) + goto err; + + desc->ubuf = kmalloc(desc->wMaxCommand, GFP_KERNEL); + if (!desc->ubuf) + goto err; + + desc->sbuf = kmalloc(desc->wMaxPacketSize, GFP_KERNEL); + if (!desc->sbuf) + goto err; + + desc->inbuf = kmalloc(desc->wMaxCommand, GFP_KERNEL); + if (!desc->inbuf) + goto err; + + usb_fill_int_urb( + desc->validity, + interface_to_usbdev(intf), + usb_rcvintpipe(interface_to_usbdev(intf), ep->bEndpointAddress), + desc->sbuf, + desc->wMaxPacketSize, + wdm_int_callback, + desc, + ep->bInterval + ); + + desc->irq->bRequestType = (USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE); + desc->irq->bRequest = USB_CDC_GET_ENCAPSULATED_RESPONSE; + desc->irq->wValue = 0; + desc->irq->wIndex = desc->inum; /* already converted */ + desc->irq->wLength = cpu_to_le16(desc->wMaxCommand); + + usb_fill_control_urb( + desc->response, + interface_to_usbdev(intf), + /* using common endpoint 0 */ + usb_rcvctrlpipe(interface_to_usbdev(desc->intf), 0), + (unsigned char *)desc->irq, + desc->inbuf, + desc->wMaxCommand, + wdm_in_callback, + desc + ); + + desc->manage_power = manage_power; + + /* + * "drain_on_open" enables a hack to work around a firmware + * issue observed on network functions, in particular MBIM + * functions. + * + * Quoting section 7 of the CDC-WMC r1.1 specification: + * + * "The firmware shall interpret GetEncapsulatedResponse as a + * request to read response bytes. The firmware shall send + * the next wLength bytes from the response. The firmware + * shall allow the host to retrieve data using any number of + * GetEncapsulatedResponse requests. The firmware shall + * return a zero- length reply if there are no data bytes + * available. + * + * The firmware shall send ResponseAvailable notifications + * periodically, using any appropriate algorithm, to inform + * the host that there is data available in the reply + * buffer. The firmware is allowed to send ResponseAvailable + * notifications even if there is no data available, but + * this will obviously reduce overall performance." + * + * These requirements, although they make equally sense, are + * often not implemented by network functions. Some firmwares + * will queue data indefinitely, without ever resending a + * notification. The result is that the driver and firmware + * loses "syncronization" if the driver ever fails to respond + * to a single notification, something which easily can happen + * on release(). When this happens, the driver will appear to + * never receive notifications for the most current data. Each + * notification will only cause a single read, which returns + * the oldest data in the firmware's queue. + * + * The "drain_on_open" hack resolves the situation by draining + * data from the firmware until none is returned, without a + * prior notification. + * + * This will inevitably race with the firmware, risking that + * we read data from the device before handling the associated + * notification. To make things worse, some of the devices + * needing the hack do not implement the "return zero if no + * data is available" requirement either. Instead they return + * an error on the subsequent read in this case. This means + * that "winning" the race can cause an unexpected EIO to + * userspace. + * + * "winning" the race is more likely on resume() than on + * open(), and the unexpected error is more harmful in the + * middle of an open session. The hack is therefore only + * applied on open(), and not on resume() where it logically + * would be equally necessary. So we define open() as the only + * driver <-> device "syncronization point". Should we happen + * to lose a notification after open(), then syncronization + * will be lost until release() + * + * The hack should not be enabled for CDC WDM devices + * conforming to the CDC-WMC r1.1 specification. This is + * ensured by setting drain_on_open to false in wdm_probe(). + */ + if (drain_on_open) + set_bit(WDM_DRAIN_ON_OPEN, &desc->flags); + + spin_lock(&wdm_device_list_lock); + list_add(&desc->device_list, &wdm_device_list); + spin_unlock(&wdm_device_list_lock); + + rv = usb_register_dev(intf, &wdm_class); + if (rv < 0) + goto err; + else + dev_info(&intf->dev, "%s: USB WDM device\n", dev_name(intf->usb_dev)); +out: + return rv; +err: + spin_lock(&wdm_device_list_lock); + list_del(&desc->device_list); + spin_unlock(&wdm_device_list_lock); + cleanup(desc); + return rv; +} + +static int wdm_manage_power(struct usb_interface *intf, int on) +{ + /* need autopm_get/put here to ensure the usbcore sees the new value */ + int rv = usb_autopm_get_interface(intf); + + intf->needs_remote_wakeup = on; + if (!rv) + usb_autopm_put_interface(intf); + return 0; +} + +static int wdm_probe(struct usb_interface *intf, const struct usb_device_id *id) +{ + int rv = -EINVAL; + struct usb_host_interface *iface; + struct usb_endpoint_descriptor *ep; + struct usb_cdc_parsed_header hdr; + u8 *buffer = intf->altsetting->extra; + int buflen = intf->altsetting->extralen; + u16 maxcom = WDM_DEFAULT_BUFSIZE; + + if (!buffer) + goto err; + + cdc_parse_cdc_header(&hdr, intf, buffer, buflen); + + if (hdr.usb_cdc_dmm_desc) + maxcom = le16_to_cpu(hdr.usb_cdc_dmm_desc->wMaxCommand); + + iface = intf->cur_altsetting; + if (iface->desc.bNumEndpoints != 1) + goto err; + ep = &iface->endpoint[0].desc; + + rv = wdm_create(intf, ep, maxcom, &wdm_manage_power, false); + +err: + return rv; +} + +/** + * usb_cdc_wdm_register - register a WDM subdriver + * @intf: usb interface the subdriver will associate with + * @ep: interrupt endpoint to monitor for notifications + * @bufsize: maximum message size to support for read/write + * + * Create WDM usb class character device and associate it with intf + * without binding, allowing another driver to manage the interface. + * + * The subdriver will manage the given interrupt endpoint exclusively + * and will issue control requests referring to the given intf. It + * will otherwise avoid interferring, and in particular not do + * usb_set_intfdata/usb_get_intfdata on intf. + * + * The return value is a pointer to the subdriver's struct usb_driver. + * The registering driver is responsible for calling this subdriver's + * disconnect, suspend, resume, pre_reset and post_reset methods from + * its own. + */ +struct usb_driver *usb_cdc_wdm_register(struct usb_interface *intf, + struct usb_endpoint_descriptor *ep, + int bufsize, + int (*manage_power)(struct usb_interface *, int)) +{ + int rv = -EINVAL; + + rv = wdm_create(intf, ep, bufsize, manage_power, true); + if (rv < 0) + goto err; + + return &wdm_driver; +err: + return ERR_PTR(rv); +} +EXPORT_SYMBOL(usb_cdc_wdm_register); + +static void wdm_disconnect(struct usb_interface *intf) +{ + struct wdm_device *desc; + unsigned long flags; + + usb_deregister_dev(intf, &wdm_class); + desc = wdm_find_device(intf); + mutex_lock(&wdm_mutex); + + /* the spinlock makes sure no new urbs are generated in the callbacks */ + spin_lock_irqsave(&desc->iuspin, flags); + set_bit(WDM_DISCONNECTING, &desc->flags); + set_bit(WDM_READ, &desc->flags); + /* to terminate pending flushes */ + clear_bit(WDM_IN_USE, &desc->flags); + spin_unlock_irqrestore(&desc->iuspin, flags); + wake_up_all(&desc->wait); + mutex_lock(&desc->rlock); + mutex_lock(&desc->wlock); + kill_urbs(desc); + cancel_work_sync(&desc->rxwork); + mutex_unlock(&desc->wlock); + mutex_unlock(&desc->rlock); + + /* the desc->intf pointer used as list key is now invalid */ + spin_lock(&wdm_device_list_lock); + list_del(&desc->device_list); + spin_unlock(&wdm_device_list_lock); + + if (!desc->count) + cleanup(desc); + else + dev_dbg(&intf->dev, "%d open files - postponing cleanup\n", desc->count); + mutex_unlock(&wdm_mutex); +} + +#ifdef CONFIG_PM +static int wdm_suspend(struct usb_interface *intf, pm_message_t message) +{ + struct wdm_device *desc = wdm_find_device(intf); + int rv = 0; + + dev_dbg(&desc->intf->dev, "wdm%d_suspend\n", intf->minor); + + /* if this is an autosuspend the caller does the locking */ + if (!PMSG_IS_AUTO(message)) { + mutex_lock(&desc->rlock); + mutex_lock(&desc->wlock); + } + spin_lock_irq(&desc->iuspin); + + if (PMSG_IS_AUTO(message) && + (test_bit(WDM_IN_USE, &desc->flags) + || test_bit(WDM_RESPONDING, &desc->flags))) { + spin_unlock_irq(&desc->iuspin); + rv = -EBUSY; + } else { + + set_bit(WDM_SUSPENDING, &desc->flags); + spin_unlock_irq(&desc->iuspin); + /* callback submits work - order is essential */ + kill_urbs(desc); + cancel_work_sync(&desc->rxwork); + } + if (!PMSG_IS_AUTO(message)) { + mutex_unlock(&desc->wlock); + mutex_unlock(&desc->rlock); + } + + return rv; +} +#endif + +static int recover_from_urb_loss(struct wdm_device *desc) +{ + int rv = 0; + + if (desc->count) { + rv = usb_submit_urb(desc->validity, GFP_NOIO); + if (rv < 0) + dev_err(&desc->intf->dev, + "Error resume submitting int urb - %d\n", rv); + } + return rv; +} + +#ifdef CONFIG_PM +static int wdm_resume(struct usb_interface *intf) +{ + struct wdm_device *desc = wdm_find_device(intf); + int rv; + + dev_dbg(&desc->intf->dev, "wdm%d_resume\n", intf->minor); + + clear_bit(WDM_SUSPENDING, &desc->flags); + rv = recover_from_urb_loss(desc); + + return rv; +} +#endif + +static int wdm_pre_reset(struct usb_interface *intf) +{ + struct wdm_device *desc = wdm_find_device(intf); + + /* + * we notify everybody using poll of + * an exceptional situation + * must be done before recovery lest a spontaneous + * message from the device is lost + */ + spin_lock_irq(&desc->iuspin); + set_bit(WDM_RESETTING, &desc->flags); /* inform read/write */ + set_bit(WDM_READ, &desc->flags); /* unblock read */ + clear_bit(WDM_IN_USE, &desc->flags); /* unblock write */ + desc->rerr = -EINTR; + spin_unlock_irq(&desc->iuspin); + wake_up_all(&desc->wait); + mutex_lock(&desc->rlock); + mutex_lock(&desc->wlock); + kill_urbs(desc); + cancel_work_sync(&desc->rxwork); + return 0; +} + +static int wdm_post_reset(struct usb_interface *intf) +{ + struct wdm_device *desc = wdm_find_device(intf); + int rv; + + clear_bit(WDM_OVERFLOW, &desc->flags); + clear_bit(WDM_RESETTING, &desc->flags); + rv = recover_from_urb_loss(desc); + mutex_unlock(&desc->wlock); + mutex_unlock(&desc->rlock); + return 0; +} + +static struct usb_driver wdm_driver = { + .name = "cdc_wdm", + .probe = wdm_probe, + .disconnect = wdm_disconnect, +#ifdef CONFIG_PM + .suspend = wdm_suspend, + .resume = wdm_resume, + .reset_resume = wdm_resume, +#endif + .pre_reset = wdm_pre_reset, + .post_reset = wdm_post_reset, + .id_table = wdm_ids, + .supports_autosuspend = 1, + .disable_hub_initiated_lpm = 1, +}; + +module_usb_driver(wdm_driver); + +MODULE_AUTHOR(DRIVER_AUTHOR); +MODULE_DESCRIPTION(DRIVER_DESC); +MODULE_LICENSE("GPL"); |