USB: gadget: f_accessory: New gadget driver for android USB accesories
Mike Lockwood [Wed, 2 Feb 2011 16:52:56 +0000 (11:52 -0500)]
Signed-off-by: Mike Lockwood <lockwood@android.com>

USB: gadget: f_accessory: Misc improvements and cleanup:

- Add URI string

- Replace type string with a description string

- Add a control call to retrieve accessory protocol version (currently 1)

- Driver read() and write() calls now fail after USB disconnect until
  driver file is closed and reopened.

- Misc cleanup work

Signed-off-by: Mike Lockwood <lockwood@android.com>

USB: gadget: f_accessory: Clear accessory strings when USB is disconnected

Signed-off-by: Mike Lockwood <lockwood@android.com>

USB: gadget: f_accessory: Clear previous strings on ACCESSORY_GET_PROTOCOL

Clearing strings on disconnect does not work since we may receive
a disconnect on some devices when transitioning into accessory mode.
We require an accessory to send ACCESSORY_GET_PROTOCOL before
sending any strings, so any strings from a previous session will be cleared.

Signed-off-by: Mike Lockwood <lockwood@android.com>

USB: gadget: f_accessory: Clear disconnected flag when driver file is opened

Fixes a race condition that can occur when entering accessory mode.

Signed-off-by: Mike Lockwood <lockwood@android.com>

USB: gadget: f_accessory: Add string for accessory's unique serial number

Signed-off-by: Mike Lockwood <lockwood@android.com>

USB: gadget: f_accessory: Set bNumEndpoints to correct value of 2

Change-Id: I24f4e36f196d45436e0573301500c3b93215953d
Signed-off-by: Mike Lockwood <lockwood@android.com>

drivers/usb/gadget/Kconfig
drivers/usb/gadget/Makefile
drivers/usb/gadget/android.c
drivers/usb/gadget/f_accessory.c [new file with mode: 0644]
include/linux/usb/f_accessory.h [new file with mode: 0644]

index 705d1e5..ffd8f1b 100644 (file)
@@ -871,6 +871,13 @@ config USB_ANDROID_RNDIS_WCEIS
          If you enable this option, the device is no longer CDC ethernet
          compatible.
 
+
+config USB_ANDROID_ACCESSORY
+       boolean "Android USB accessory function"
+       depends on USB_ANDROID
+       help
+         Provides Android USB Accessory support for android gadget driver.
+
 config USB_CDC_COMPOSITE
        tristate "CDC Composite Device (Ethernet and ACM)"
        depends on NET
index 82cf238..51eca09 100644 (file)
@@ -75,3 +75,4 @@ obj-$(CONFIG_USB_ANDROID_ADB) += f_adb.o
 obj-$(CONFIG_USB_ANDROID_MASS_STORAGE) += f_mass_storage.o
 obj-$(CONFIG_USB_ANDROID_MTP)  += f_mtp.o
 obj-$(CONFIG_USB_ANDROID_RNDIS)        += f_rndis.o u_ether.o
+obj-$(CONFIG_USB_ANDROID_ACCESSORY)    += f_accessory.o
index eb6af6d..2ebc818 100644 (file)
@@ -430,6 +430,19 @@ void android_enable_function(struct usb_function *f, int enable)
                        }
                }
 #endif
+#ifdef CONFIG_USB_ANDROID_ACCESSORY
+               if (!strcmp(f->name, "accessory") && enable) {
+                       struct usb_function             *func;
+
+                   /* disable everything else (and keep adb for now) */
+                       list_for_each_entry(func, &android_config_driver.functions, list) {
+                               if (strcmp(func->name, "accessory")
+                                       && strcmp(func->name, "adb")) {
+                                       usb_function_set_enabled(func, 0);
+                               }
+                       }
+        }
+#endif
 
                update_dev_desc(dev);
 
diff --git a/drivers/usb/gadget/f_accessory.c b/drivers/usb/gadget/f_accessory.c
new file mode 100644 (file)
index 0000000..ad3c173
--- /dev/null
@@ -0,0 +1,808 @@
+/*
+ * Gadget Function Driver for Android USB accessories
+ *
+ * Copyright (C) 2011 Google, Inc.
+ * Author: Mike Lockwood <lockwood@android.com>
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+/* #define DEBUG */
+/* #define VERBOSE_DEBUG */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/poll.h>
+#include <linux/delay.h>
+#include <linux/wait.h>
+#include <linux/err.h>
+#include <linux/interrupt.h>
+#include <linux/kthread.h>
+#include <linux/freezer.h>
+
+#include <linux/types.h>
+#include <linux/file.h>
+#include <linux/device.h>
+#include <linux/miscdevice.h>
+
+#include <linux/usb.h>
+#include <linux/usb/ch9.h>
+#include <linux/usb/android_composite.h>
+#include <linux/usb/f_accessory.h>
+
+#define BULK_BUFFER_SIZE    16384
+#define ACC_STRING_SIZE     256
+
+#define PROTOCOL_VERSION    1
+
+/* String IDs */
+#define INTERFACE_STRING_INDEX 0
+
+/* number of tx and rx requests to allocate */
+#define TX_REQ_MAX 4
+#define RX_REQ_MAX 2
+
+struct acc_dev {
+       struct usb_function function;
+       struct usb_composite_dev *cdev;
+       spinlock_t lock;
+
+       struct usb_ep *ep_in;
+       struct usb_ep *ep_out;
+
+       /* set to 1 when we connect */
+       int online:1;
+       /* Set to 1 when we disconnect.
+        * Not cleared until our file is closed.
+        */
+       int disconnected:1;
+
+       /* strings sent by the host */
+       char manufacturer[ACC_STRING_SIZE];
+       char model[ACC_STRING_SIZE];
+       char description[ACC_STRING_SIZE];
+       char version[ACC_STRING_SIZE];
+       char uri[ACC_STRING_SIZE];
+       char serial[ACC_STRING_SIZE];
+
+       /* for acc_complete_set_string */
+       int string_index;
+
+       /* synchronize access to our device file */
+       atomic_t open_excl;
+
+       struct list_head tx_idle;
+
+       wait_queue_head_t read_wq;
+       wait_queue_head_t write_wq;
+       struct usb_request *rx_req[RX_REQ_MAX];
+       int rx_done;
+       struct delayed_work work;
+};
+
+static struct usb_interface_descriptor acc_interface_desc = {
+       .bLength                = USB_DT_INTERFACE_SIZE,
+       .bDescriptorType        = USB_DT_INTERFACE,
+       .bInterfaceNumber       = 0,
+       .bNumEndpoints          = 2,
+       .bInterfaceClass        = USB_CLASS_VENDOR_SPEC,
+       .bInterfaceSubClass     = USB_SUBCLASS_VENDOR_SPEC,
+       .bInterfaceProtocol     = 0,
+};
+
+static struct usb_endpoint_descriptor acc_highspeed_in_desc = {
+       .bLength                = USB_DT_ENDPOINT_SIZE,
+       .bDescriptorType        = USB_DT_ENDPOINT,
+       .bEndpointAddress       = USB_DIR_IN,
+       .bmAttributes           = USB_ENDPOINT_XFER_BULK,
+       .wMaxPacketSize         = __constant_cpu_to_le16(512),
+};
+
+static struct usb_endpoint_descriptor acc_highspeed_out_desc = {
+       .bLength                = USB_DT_ENDPOINT_SIZE,
+       .bDescriptorType        = USB_DT_ENDPOINT,
+       .bEndpointAddress       = USB_DIR_OUT,
+       .bmAttributes           = USB_ENDPOINT_XFER_BULK,
+       .wMaxPacketSize         = __constant_cpu_to_le16(512),
+};
+
+static struct usb_endpoint_descriptor acc_fullspeed_in_desc = {
+       .bLength                = USB_DT_ENDPOINT_SIZE,
+       .bDescriptorType        = USB_DT_ENDPOINT,
+       .bEndpointAddress       = USB_DIR_IN,
+       .bmAttributes           = USB_ENDPOINT_XFER_BULK,
+};
+
+static struct usb_endpoint_descriptor acc_fullspeed_out_desc = {
+       .bLength                = USB_DT_ENDPOINT_SIZE,
+       .bDescriptorType        = USB_DT_ENDPOINT,
+       .bEndpointAddress       = USB_DIR_OUT,
+       .bmAttributes           = USB_ENDPOINT_XFER_BULK,
+};
+
+static struct usb_descriptor_header *fs_acc_descs[] = {
+       (struct usb_descriptor_header *) &acc_interface_desc,
+       (struct usb_descriptor_header *) &acc_fullspeed_in_desc,
+       (struct usb_descriptor_header *) &acc_fullspeed_out_desc,
+       NULL,
+};
+
+static struct usb_descriptor_header *hs_acc_descs[] = {
+       (struct usb_descriptor_header *) &acc_interface_desc,
+       (struct usb_descriptor_header *) &acc_highspeed_in_desc,
+       (struct usb_descriptor_header *) &acc_highspeed_out_desc,
+       NULL,
+};
+
+static struct usb_string acc_string_defs[] = {
+       [INTERFACE_STRING_INDEX].s      = "Android Accessory Interface",
+       {  },   /* end of list */
+};
+
+static struct usb_gadget_strings acc_string_table = {
+       .language               = 0x0409,       /* en-US */
+       .strings                = acc_string_defs,
+};
+
+static struct usb_gadget_strings *acc_strings[] = {
+       &acc_string_table,
+       NULL,
+};
+
+/* temporary variable used between acc_open() and acc_gadget_bind() */
+static struct acc_dev *_acc_dev;
+
+static inline struct acc_dev *func_to_dev(struct usb_function *f)
+{
+       return container_of(f, struct acc_dev, function);
+}
+
+static struct usb_request *acc_request_new(struct usb_ep *ep, int buffer_size)
+{
+       struct usb_request *req = usb_ep_alloc_request(ep, GFP_KERNEL);
+       if (!req)
+               return NULL;
+
+       /* now allocate buffers for the requests */
+       req->buf = kmalloc(buffer_size, GFP_KERNEL);
+       if (!req->buf) {
+               usb_ep_free_request(ep, req);
+               return NULL;
+       }
+
+       return req;
+}
+
+static void acc_request_free(struct usb_request *req, struct usb_ep *ep)
+{
+       if (req) {
+               kfree(req->buf);
+               usb_ep_free_request(ep, req);
+       }
+}
+
+/* add a request to the tail of a list */
+static void req_put(struct acc_dev *dev, struct list_head *head,
+               struct usb_request *req)
+{
+       unsigned long flags;
+
+       spin_lock_irqsave(&dev->lock, flags);
+       list_add_tail(&req->list, head);
+       spin_unlock_irqrestore(&dev->lock, flags);
+}
+
+/* remove a request from the head of a list */
+static struct usb_request *req_get(struct acc_dev *dev, struct list_head *head)
+{
+       unsigned long flags;
+       struct usb_request *req;
+
+       spin_lock_irqsave(&dev->lock, flags);
+       if (list_empty(head)) {
+               req = 0;
+       } else {
+               req = list_first_entry(head, struct usb_request, list);
+               list_del(&req->list);
+       }
+       spin_unlock_irqrestore(&dev->lock, flags);
+       return req;
+}
+
+static void acc_set_disconnected(struct acc_dev *dev)
+{
+       dev->online = 0;
+       dev->disconnected = 1;
+}
+
+static void acc_complete_in(struct usb_ep *ep, struct usb_request *req)
+{
+       struct acc_dev *dev = _acc_dev;
+
+       if (req->status != 0)
+               acc_set_disconnected(dev);
+
+       req_put(dev, &dev->tx_idle, req);
+
+       wake_up(&dev->write_wq);
+}
+
+static void acc_complete_out(struct usb_ep *ep, struct usb_request *req)
+{
+       struct acc_dev *dev = _acc_dev;
+
+       dev->rx_done = 1;
+       if (req->status != 0)
+               acc_set_disconnected(dev);
+
+       wake_up(&dev->read_wq);
+}
+
+static void acc_complete_set_string(struct usb_ep *ep, struct usb_request *req)
+{
+       struct acc_dev  *dev = ep->driver_data;
+       struct usb_composite_dev *cdev = dev->cdev;
+       char *string_dest = NULL;
+       int length = req->actual;
+
+       if (req->status != 0) {
+               DBG(cdev, "acc_complete_set_string, err %d\n", req->status);
+               return;
+       }
+
+       switch (dev->string_index) {
+       case ACCESSORY_STRING_MANUFACTURER:
+               string_dest = dev->manufacturer;
+               break;
+       case ACCESSORY_STRING_MODEL:
+               string_dest = dev->model;
+               break;
+       case ACCESSORY_STRING_DESCRIPTION:
+               string_dest = dev->description;
+               break;
+       case ACCESSORY_STRING_VERSION:
+               string_dest = dev->version;
+               break;
+       case ACCESSORY_STRING_URI:
+               string_dest = dev->uri;
+               break;
+       case ACCESSORY_STRING_SERIAL:
+               string_dest = dev->serial;
+               break;
+       }
+       if (string_dest) {
+               unsigned long flags;
+
+               if (length >= ACC_STRING_SIZE)
+                       length = ACC_STRING_SIZE - 1;
+
+               spin_lock_irqsave(&dev->lock, flags);
+               memcpy(string_dest, cdev->req->buf, length);
+               /* ensure zero termination */
+               string_dest[length] = 0;
+               spin_unlock_irqrestore(&dev->lock, flags);
+       } else {
+               DBG(cdev, "unknown accessory string index %d\n",
+                       dev->string_index);
+       }
+}
+
+static int __init create_bulk_endpoints(struct acc_dev *dev,
+                               struct usb_endpoint_descriptor *in_desc,
+                               struct usb_endpoint_descriptor *out_desc)
+{
+       struct usb_composite_dev *cdev = dev->cdev;
+       struct usb_request *req;
+       struct usb_ep *ep;
+       int i;
+
+       DBG(cdev, "create_bulk_endpoints dev: %p\n", dev);
+
+       ep = usb_ep_autoconfig(cdev->gadget, in_desc);
+       if (!ep) {
+               DBG(cdev, "usb_ep_autoconfig for ep_in failed\n");
+               return -ENODEV;
+       }
+       DBG(cdev, "usb_ep_autoconfig for ep_in got %s\n", ep->name);
+       ep->driver_data = dev;          /* claim the endpoint */
+       dev->ep_in = ep;
+
+       ep = usb_ep_autoconfig(cdev->gadget, out_desc);
+       if (!ep) {
+               DBG(cdev, "usb_ep_autoconfig for ep_out failed\n");
+               return -ENODEV;
+       }
+       DBG(cdev, "usb_ep_autoconfig for ep_out got %s\n", ep->name);
+       ep->driver_data = dev;          /* claim the endpoint */
+       dev->ep_out = ep;
+
+       ep = usb_ep_autoconfig(cdev->gadget, out_desc);
+       if (!ep) {
+               DBG(cdev, "usb_ep_autoconfig for ep_out failed\n");
+               return -ENODEV;
+       }
+       DBG(cdev, "usb_ep_autoconfig for ep_out got %s\n", ep->name);
+       ep->driver_data = dev;          /* claim the endpoint */
+       dev->ep_out = ep;
+
+       /* now allocate requests for our endpoints */
+       for (i = 0; i < TX_REQ_MAX; i++) {
+               req = acc_request_new(dev->ep_in, BULK_BUFFER_SIZE);
+               if (!req)
+                       goto fail;
+               req->complete = acc_complete_in;
+               req_put(dev, &dev->tx_idle, req);
+       }
+       for (i = 0; i < RX_REQ_MAX; i++) {
+               req = acc_request_new(dev->ep_out, BULK_BUFFER_SIZE);
+               if (!req)
+                       goto fail;
+               req->complete = acc_complete_out;
+               dev->rx_req[i] = req;
+       }
+
+       return 0;
+
+fail:
+       printk(KERN_ERR "acc_bind() could not allocate requests\n");
+       while ((req = req_get(dev, &dev->tx_idle)))
+               acc_request_free(req, dev->ep_in);
+       for (i = 0; i < RX_REQ_MAX; i++)
+               acc_request_free(dev->rx_req[i], dev->ep_out);
+       return -1;
+}
+
+static ssize_t acc_read(struct file *fp, char __user *buf,
+       size_t count, loff_t *pos)
+{
+       struct acc_dev *dev = fp->private_data;
+       struct usb_composite_dev *cdev = dev->cdev;
+       struct usb_request *req;
+       int r = count, xfer;
+       int ret = 0;
+
+       DBG(cdev, "acc_read(%d)\n", count);
+
+       if (dev->disconnected)
+               return -ENODEV;
+
+       if (count > BULK_BUFFER_SIZE)
+               count = BULK_BUFFER_SIZE;
+
+       /* we will block until we're online */
+       DBG(cdev, "acc_read: waiting for online\n");
+       ret = wait_event_interruptible(dev->read_wq, dev->online);
+       if (ret < 0) {
+               r = ret;
+               goto done;
+       }
+
+requeue_req:
+       /* queue a request */
+       req = dev->rx_req[0];
+       req->length = count;
+       dev->rx_done = 0;
+       ret = usb_ep_queue(dev->ep_out, req, GFP_KERNEL);
+       if (ret < 0) {
+               r = -EIO;
+               goto done;
+       } else {
+               DBG(cdev, "rx %p queue\n", req);
+       }
+
+       /* wait for a request to complete */
+       ret = wait_event_interruptible(dev->read_wq, dev->rx_done);
+       if (ret < 0) {
+               r = ret;
+               usb_ep_dequeue(dev->ep_out, req);
+               goto done;
+       }
+       if (dev->online) {
+               /* If we got a 0-len packet, throw it back and try again. */
+               if (req->actual == 0)
+                       goto requeue_req;
+
+               DBG(cdev, "rx %p %d\n", req, req->actual);
+               xfer = (req->actual < count) ? req->actual : count;
+               r = xfer;
+               if (copy_to_user(buf, req->buf, xfer))
+                       r = -EFAULT;
+       } else
+               r = -EIO;
+
+done:
+       DBG(cdev, "acc_read returning %d\n", r);
+       return r;
+}
+
+static ssize_t acc_write(struct file *fp, const char __user *buf,
+       size_t count, loff_t *pos)
+{
+       struct acc_dev *dev = fp->private_data;
+       struct usb_composite_dev *cdev = dev->cdev;
+       struct usb_request *req = 0;
+       int r = count, xfer;
+       int ret;
+
+       DBG(cdev, "acc_write(%d)\n", count);
+
+       if (!dev->online || dev->disconnected)
+               return -ENODEV;
+
+       while (count > 0) {
+               if (!dev->online) {
+                       DBG(cdev, "acc_write dev->error\n");
+                       r = -EIO;
+                       break;
+               }
+
+               /* get an idle tx request to use */
+               req = 0;
+               ret = wait_event_interruptible(dev->write_wq,
+                       ((req = req_get(dev, &dev->tx_idle)) || !dev->online));
+               if (!req) {
+                       r = ret;
+                       break;
+               }
+
+               if (count > BULK_BUFFER_SIZE)
+                       xfer = BULK_BUFFER_SIZE;
+               else
+                       xfer = count;
+               if (copy_from_user(req->buf, buf, xfer)) {
+                       r = -EFAULT;
+                       break;
+               }
+
+               req->length = xfer;
+               ret = usb_ep_queue(dev->ep_in, req, GFP_KERNEL);
+               if (ret < 0) {
+                       DBG(cdev, "acc_write: xfer error %d\n", ret);
+                       r = -EIO;
+                       break;
+               }
+
+               buf += xfer;
+               count -= xfer;
+
+               /* zero this so we don't try to free it on error exit */
+               req = 0;
+       }
+
+       if (req)
+               req_put(dev, &dev->tx_idle, req);
+
+       DBG(cdev, "acc_write returning %d\n", r);
+       return r;
+}
+
+static long acc_ioctl(struct file *fp, unsigned code, unsigned long value)
+{
+       struct acc_dev *dev = fp->private_data;
+       char *src = NULL;
+       int ret;
+
+       if (dev->function.disabled)
+               return -ENODEV;
+
+       switch (code) {
+       case ACCESSORY_GET_STRING_MANUFACTURER:
+               src = dev->manufacturer;
+               break;
+       case ACCESSORY_GET_STRING_MODEL:
+               src = dev->model;
+               break;
+       case ACCESSORY_GET_STRING_DESCRIPTION:
+               src = dev->description;
+               break;
+       case ACCESSORY_GET_STRING_VERSION:
+               src = dev->version;
+               break;
+       case ACCESSORY_GET_STRING_URI:
+               src = dev->uri;
+               break;
+       case ACCESSORY_GET_STRING_SERIAL:
+               src = dev->serial;
+               break;
+       }
+       if (!src)
+               return -EINVAL;
+
+       ret = strlen(src) + 1;
+       if (copy_to_user((void __user *)value, src, ret))
+               ret = -EFAULT;
+       return ret;
+}
+
+static int acc_open(struct inode *ip, struct file *fp)
+{
+       printk(KERN_INFO "acc_open\n");
+       if (atomic_xchg(&_acc_dev->open_excl, 1))
+               return -EBUSY;
+
+       _acc_dev->disconnected = 0;
+       fp->private_data = _acc_dev;
+       return 0;
+}
+
+static int acc_release(struct inode *ip, struct file *fp)
+{
+       printk(KERN_INFO "acc_release\n");
+
+       WARN_ON(!atomic_xchg(&_acc_dev->open_excl, 0));
+       _acc_dev->disconnected = 0;
+       return 0;
+}
+
+/* file operations for /dev/acc_usb */
+static const struct file_operations acc_fops = {
+       .owner = THIS_MODULE,
+       .read = acc_read,
+       .write = acc_write,
+       .unlocked_ioctl = acc_ioctl,
+       .open = acc_open,
+       .release = acc_release,
+};
+
+static struct miscdevice acc_device = {
+       .minor = MISC_DYNAMIC_MINOR,
+       .name = "usb_accessory",
+       .fops = &acc_fops,
+};
+
+static int
+acc_function_bind(struct usb_configuration *c, struct usb_function *f)
+{
+       struct usb_composite_dev *cdev = c->cdev;
+       struct acc_dev  *dev = func_to_dev(f);
+       int                     id;
+       int                     ret;
+
+       dev->cdev = cdev;
+       DBG(cdev, "acc_function_bind dev: %p\n", dev);
+
+       /* allocate interface ID(s) */
+       id = usb_interface_id(c, f);
+       if (id < 0)
+               return id;
+       acc_interface_desc.bInterfaceNumber = id;
+
+       /* allocate endpoints */
+       ret = create_bulk_endpoints(dev, &acc_fullspeed_in_desc,
+                       &acc_fullspeed_out_desc);
+       if (ret)
+               return ret;
+
+       /* support high speed hardware */
+       if (gadget_is_dualspeed(c->cdev->gadget)) {
+               acc_highspeed_in_desc.bEndpointAddress =
+                       acc_fullspeed_in_desc.bEndpointAddress;
+               acc_highspeed_out_desc.bEndpointAddress =
+                       acc_fullspeed_out_desc.bEndpointAddress;
+       }
+
+       DBG(cdev, "%s speed %s: IN/%s, OUT/%s\n",
+                       gadget_is_dualspeed(c->cdev->gadget) ? "dual" : "full",
+                       f->name, dev->ep_in->name, dev->ep_out->name);
+       return 0;
+}
+
+static void
+acc_function_unbind(struct usb_configuration *c, struct usb_function *f)
+{
+       struct acc_dev  *dev = func_to_dev(f);
+       struct usb_request *req;
+       int i;
+
+       spin_lock_irq(&dev->lock);
+       while ((req = req_get(dev, &dev->tx_idle)))
+               acc_request_free(req, dev->ep_in);
+       for (i = 0; i < RX_REQ_MAX; i++)
+               acc_request_free(dev->rx_req[i], dev->ep_out);
+       dev->online = 0;
+       spin_unlock_irq(&dev->lock);
+
+       misc_deregister(&acc_device);
+       kfree(_acc_dev);
+       _acc_dev = NULL;
+}
+
+static void acc_work(struct work_struct *data)
+{
+       struct delayed_work *delayed = to_delayed_work(data);
+       struct acc_dev  *dev =
+               container_of(delayed, struct acc_dev, work);
+       android_enable_function(&dev->function, 1);
+}
+
+static int acc_function_setup(struct usb_function *f,
+                                       const struct usb_ctrlrequest *ctrl)
+{
+       struct acc_dev  *dev = func_to_dev(f);
+       struct usb_composite_dev *cdev = dev->cdev;
+       int     value = -EOPNOTSUPP;
+       u8 b_requestType = ctrl->bRequestType;
+       u8 b_request = ctrl->bRequest;
+       u16     w_index = le16_to_cpu(ctrl->wIndex);
+       u16     w_value = le16_to_cpu(ctrl->wValue);
+       u16     w_length = le16_to_cpu(ctrl->wLength);
+
+/*
+       printk(KERN_INFO "acc_function_setup "
+                       "%02x.%02x v%04x i%04x l%u\n",
+                       b_requestType, b_request,
+                       w_value, w_index, w_length);
+*/
+
+       if (dev->function.disabled) {
+               if (b_requestType == (USB_DIR_OUT | USB_TYPE_VENDOR)) {
+                       if (b_request == ACCESSORY_START) {
+                               schedule_delayed_work(
+                                       &dev->work, msecs_to_jiffies(10));
+                               value = 0;
+                       } else if (b_request == ACCESSORY_SEND_STRING) {
+                               dev->string_index = w_index;
+                               cdev->gadget->ep0->driver_data = dev;
+                               cdev->req->complete = acc_complete_set_string;
+                               value = w_length;
+                       }
+               } else if (b_requestType == (USB_DIR_IN | USB_TYPE_VENDOR)) {
+                       if (b_request == ACCESSORY_GET_PROTOCOL) {
+                               *((u16 *)cdev->req->buf) = PROTOCOL_VERSION;
+                               value = sizeof(u16);
+
+                               /* clear any strings left over from a previous session */
+                               memset(dev->manufacturer, 0, sizeof(dev->manufacturer));
+                               memset(dev->model, 0, sizeof(dev->model));
+                               memset(dev->description, 0, sizeof(dev->description));
+                               memset(dev->version, 0, sizeof(dev->version));
+                               memset(dev->uri, 0, sizeof(dev->uri));
+                               memset(dev->serial, 0, sizeof(dev->serial));
+                       }
+               }
+       }
+
+       if (value >= 0) {
+               cdev->req->zero = 0;
+               cdev->req->length = value;
+               value = usb_ep_queue(cdev->gadget->ep0, cdev->req, GFP_ATOMIC);
+               if (value < 0)
+                       ERROR(cdev, "%s setup response queue error\n",
+                               __func__);
+       }
+
+       if (value == -EOPNOTSUPP)
+               VDBG(cdev,
+                       "unknown class-specific control req "
+                       "%02x.%02x v%04x i%04x l%u\n",
+                       ctrl->bRequestType, ctrl->bRequest,
+                       w_value, w_index, w_length);
+       return value;
+}
+
+static int acc_function_set_alt(struct usb_function *f,
+               unsigned intf, unsigned alt)
+{
+       struct acc_dev  *dev = func_to_dev(f);
+       struct usb_composite_dev *cdev = f->config->cdev;
+       int ret;
+
+       DBG(cdev, "acc_function_set_alt intf: %d alt: %d\n", intf, alt);
+       ret = usb_ep_enable(dev->ep_in,
+                       ep_choose(cdev->gadget,
+                               &acc_highspeed_in_desc,
+                               &acc_fullspeed_in_desc));
+       if (ret)
+               return ret;
+       ret = usb_ep_enable(dev->ep_out,
+                       ep_choose(cdev->gadget,
+                               &acc_highspeed_out_desc,
+                               &acc_fullspeed_out_desc));
+       if (ret) {
+               usb_ep_disable(dev->ep_in);
+               return ret;
+       }
+       if (!dev->function.disabled)
+               dev->online = 1;
+
+       /* readers may be blocked waiting for us to go online */
+       wake_up(&dev->read_wq);
+       return 0;
+}
+
+static void acc_function_disable(struct usb_function *f)
+{
+       struct acc_dev  *dev = func_to_dev(f);
+       struct usb_composite_dev        *cdev = dev->cdev;
+
+       DBG(cdev, "acc_function_disable\n");
+       acc_set_disconnected(dev);
+       usb_ep_disable(dev->ep_in);
+       usb_ep_disable(dev->ep_out);
+
+       /* readers may be blocked waiting for us to go online */
+       wake_up(&dev->read_wq);
+
+       VDBG(cdev, "%s disabled\n", dev->function.name);
+}
+
+static int acc_bind_config(struct usb_configuration *c)
+{
+       struct acc_dev *dev;
+       int ret;
+
+       printk(KERN_INFO "acc_bind_config\n");
+
+       dev = kzalloc(sizeof(*dev), GFP_KERNEL);
+       if (!dev)
+               return -ENOMEM;
+
+       /* allocate a string ID for our interface */
+       if (acc_string_defs[INTERFACE_STRING_INDEX].id == 0) {
+               ret = usb_string_id(c->cdev);
+               if (ret < 0)
+                       return ret;
+               acc_string_defs[INTERFACE_STRING_INDEX].id = ret;
+               acc_interface_desc.iInterface = ret;
+       }
+
+       spin_lock_init(&dev->lock);
+       init_waitqueue_head(&dev->read_wq);
+       init_waitqueue_head(&dev->write_wq);
+       atomic_set(&dev->open_excl, 0);
+       INIT_LIST_HEAD(&dev->tx_idle);
+       INIT_DELAYED_WORK(&dev->work, acc_work);
+
+       dev->cdev = c->cdev;
+       dev->function.name = "accessory";
+       dev->function.strings = acc_strings,
+       dev->function.descriptors = fs_acc_descs;
+       dev->function.hs_descriptors = hs_acc_descs;
+       dev->function.bind = acc_function_bind;
+       dev->function.unbind = acc_function_unbind;
+       dev->function.setup = acc_function_setup;
+       dev->function.set_alt = acc_function_set_alt;
+       dev->function.disable = acc_function_disable;
+       dev->function.disabled = 1;
+
+       /* _acc_dev must be set before calling usb_gadget_register_driver */
+       _acc_dev = dev;
+
+       ret = misc_register(&acc_device);
+       if (ret)
+               goto err1;
+
+       ret = usb_add_function(c, &dev->function);
+       if (ret)
+               goto err2;
+
+       return 0;
+
+err2:
+       misc_deregister(&acc_device);
+err1:
+       kfree(dev);
+       printk(KERN_ERR "USB accessory gadget driver failed to initialize\n");
+       return ret;
+}
+
+static struct android_usb_function acc_function = {
+       .name = "accessory",
+       .bind_config = acc_bind_config,
+};
+
+static int __init init(void)
+{
+       printk(KERN_INFO "f_accessory init\n");
+       android_register_function(&acc_function);
+       return 0;
+}
+module_init(init);
diff --git a/include/linux/usb/f_accessory.h b/include/linux/usb/f_accessory.h
new file mode 100644 (file)
index 0000000..ebcc5f3
--- /dev/null
@@ -0,0 +1,81 @@
+/*
+ * Gadget Function Driver for Android USB accessories
+ *
+ * Copyright (C) 2011 Google, Inc.
+ * Author: Mike Lockwood <lockwood@android.com>
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#ifndef __LINUX_USB_F_ACCESSORY_H
+#define __LINUX_USB_F_ACCESSORY_H
+
+/* Use Google Vendor ID when in accessory mode */
+#define USB_ACCESSORY_VENDOR_ID 0x18D1
+
+
+/* Product ID to use when in accessory mode */
+#define USB_ACCESSORY_PRODUCT_ID 0x2D00
+
+/* Product ID to use when in accessory mode and adb is enabled */
+#define USB_ACCESSORY_ADB_PRODUCT_ID 0x2D01
+
+/* Indexes for strings sent by the host via ACCESSORY_SEND_STRING */
+#define ACCESSORY_STRING_MANUFACTURER   0
+#define ACCESSORY_STRING_MODEL          1
+#define ACCESSORY_STRING_DESCRIPTION    2
+#define ACCESSORY_STRING_VERSION        3
+#define ACCESSORY_STRING_URI            4
+#define ACCESSORY_STRING_SERIAL         5
+
+/* Control request for retrieving device's protocol version (currently 1)
+ *
+ *     requestType:    USB_DIR_IN | USB_TYPE_VENDOR
+ *     request:        ACCESSORY_GET_PROTOCOL
+ *     value:          0
+ *     index:          0
+ *     data            version number (16 bits little endian)
+ */
+#define ACCESSORY_GET_PROTOCOL  51
+
+/* Control request for host to send a string to the device
+ *
+ *     requestType:    USB_DIR_OUT | USB_TYPE_VENDOR
+ *     request:        ACCESSORY_SEND_STRING
+ *     value:          0
+ *     index:          string ID
+ *     data            zero terminated UTF8 string
+ *
+ *  The device can later retrieve these strings via the
+ *  ACCESSORY_GET_STRING_* ioctls
+ */
+#define ACCESSORY_SEND_STRING   52
+
+/* Control request for starting device in accessory mode.
+ * The host sends this after setting all its strings to the device.
+ *
+ *     requestType:    USB_DIR_OUT | USB_TYPE_VENDOR
+ *     request:        ACCESSORY_START
+ *     value:          0
+ *     index:          0
+ *     data            none
+ */
+#define ACCESSORY_START         53
+
+/* ioctls for retrieving strings set by the host */
+#define ACCESSORY_GET_STRING_MANUFACTURER   _IOW('M', 1, char[256])
+#define ACCESSORY_GET_STRING_MODEL          _IOW('M', 2, char[256])
+#define ACCESSORY_GET_STRING_DESCRIPTION    _IOW('M', 3, char[256])
+#define ACCESSORY_GET_STRING_VERSION        _IOW('M', 4, char[256])
+#define ACCESSORY_GET_STRING_URI            _IOW('M', 5, char[256])
+#define ACCESSORY_GET_STRING_SERIAL         _IOW('M', 6, char[256])
+
+#endif /* __LINUX_USB_F_ACCESSORY_H */