v4.19.13 snapshot.
diff --git a/drivers/usb/class/cdc-wdm.c b/drivers/usb/class/cdc-wdm.c
new file mode 100644
index 0000000..bec581f
--- /dev/null
+++ b/drivers/usb/class/cdc-wdm.c
@@ -0,0 +1,1125 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * 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>
+
+#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_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;
+ struct work_struct service_outs_intr;
+ 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;
+ unsigned long flags;
+
+ desc = urb->context;
+ spin_lock_irqsave(&desc->iuspin, flags);
+ desc->werr = urb->status;
+ spin_unlock_irqrestore(&desc->iuspin, flags);
+ kfree(desc->outbuf);
+ desc->outbuf = NULL;
+ clear_bit(WDM_IN_USE, &desc->flags);
+ wake_up(&desc->wait);
+}
+
+static void wdm_in_callback(struct urb *urb)
+{
+ unsigned long flags;
+ struct wdm_device *desc = urb->context;
+ int status = urb->status;
+ int length = urb->actual_length;
+
+ spin_lock_irqsave(&desc->iuspin, flags);
+ 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_err(&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
+ * Avoid propagating -EPIPE (stall) to userspace since it is
+ * better handled as an empty read
+ */
+ if (desc->rerr == 0 && status != -EPIPE)
+ 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;
+ }
+ }
+skip_error:
+
+ 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.
+ */
+ schedule_work(&desc->service_outs_intr);
+ } else {
+ set_bit(WDM_READ, &desc->flags);
+ wake_up(&desc->wait);
+ }
+ spin_unlock_irqrestore(&desc->iuspin, flags);
+}
+
+static void wdm_int_callback(struct urb *urb)
+{
+ unsigned long flags;
+ 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_irqsave(&desc->iuspin, flags);
+ 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_irqrestore(&desc->iuspin, flags);
+ 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 = memdup_user(buffer, count);
+ if (IS_ERR(buf))
+ return PTR_ERR(buf);
+
+ /* 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);
+ return 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 = READ_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 __poll_t wdm_poll(struct file *file, struct poll_table_struct *wait)
+{
+ struct wdm_device *desc = file->private_data;
+ unsigned long flags;
+ __poll_t mask = 0;
+
+ spin_lock_irqsave(&desc->iuspin, flags);
+ if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
+ mask = EPOLLHUP | EPOLLERR;
+ spin_unlock_irqrestore(&desc->iuspin, flags);
+ goto desc_out;
+ }
+ if (test_bit(WDM_READ, &desc->flags))
+ mask = EPOLLIN | EPOLLRDNORM;
+ if (desc->rerr || desc->werr)
+ mask |= EPOLLERR;
+ if (!test_bit(WDM_IN_USE, &desc->flags))
+ mask |= EPOLLOUT | EPOLLWRNORM;
+ 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 {
+ 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);
+ }
+ }
+}
+
+static void service_interrupt_work(struct work_struct *work)
+{
+ struct wdm_device *desc;
+
+ desc = container_of(work, struct wdm_device, service_outs_intr);
+
+ spin_lock_irq(&desc->iuspin);
+ service_outstanding_interrupt(desc);
+ if (!desc->resp_count) {
+ set_bit(WDM_READ, &desc->flags);
+ wake_up(&desc->wait);
+ }
+ spin_unlock_irq(&desc->iuspin);
+}
+
+/* --- hotplug --- */
+
+static int wdm_create(struct usb_interface *intf, struct usb_endpoint_descriptor *ep,
+ u16 bufsize, int (*manage_power)(struct usb_interface *, int))
+{
+ 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);
+ INIT_WORK(&desc->service_outs_intr, service_interrupt_work);
+
+ 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;
+
+ 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);
+
+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);
+ 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);
+ cancel_work_sync(&desc->service_outs_intr);
+ 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);
+ cancel_work_sync(&desc->service_outs_intr);
+ }
+ 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);
+ cancel_work_sync(&desc->service_outs_intr);
+ 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");