/* * Gadget Function Driver for Android USB accessories * * Copyright (C) 2011 Google, Inc. * Author: Mike Lockwood * * 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 #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #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; /* set to 1 if we have a pending start request */ int start_requested; /* 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; char *string_dest = NULL; int length = req->actual; if (req->status != 0) { pr_err("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, req->buf, length); /* ensure zero termination */ string_dest[length] = 0; spin_unlock_irqrestore(&dev->lock, flags); } else { pr_err("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_request *req; int r = count, xfer; int ret = 0; pr_debug("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 */ pr_debug("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 { pr_debug("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; pr_debug("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: pr_debug("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_request *req = 0; int r = count, xfer; int ret; pr_debug("acc_write(%d)\n", count); if (!dev->online || dev->disconnected) return -ENODEV; while (count > 0) { if (!dev->online) { pr_debug("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) { pr_debug("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); pr_debug("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; 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; case ACCESSORY_IS_START_REQUESTED: return dev->start_requested; } 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_ctrlrequest(struct usb_composite_dev *cdev, const struct usb_ctrlrequest *ctrl) { struct acc_dev *dev = _acc_dev; 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_ctrlrequest " "%02x.%02x v%04x i%04x l%u\n", b_requestType, b_request, w_value, w_index, w_length); */ if (b_requestType == (USB_DIR_OUT | USB_TYPE_VENDOR)) { if (b_request == ACCESSORY_START) { dev->start_requested = 1; 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)); dev->start_requested = 0; } } 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_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; DBG(cdev, "acc_function_bind dev: %p\n", dev); dev->start_requested = 0; /* 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; 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); } static void acc_work(struct work_struct *data) { char *envp[2] = { "ACCESSORY=START", NULL }; kobject_uevent_env(&acc_device.this_device->kobj, KOBJ_CHANGE, envp); } 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); config_ep_by_speed(cdev->gadget, f, dev->ep_in); ret = usb_ep_enable(dev->ep_in); if (ret) return ret; config_ep_by_speed(cdev->gadget, f, dev->ep_out); ret = usb_ep_enable(dev->ep_out); if (ret) { usb_ep_disable(dev->ep_in); return ret; } 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 = _acc_dev; int ret; printk(KERN_INFO "acc_bind_config\n"); /* 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; } 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.set_alt = acc_function_set_alt; dev->function.disable = acc_function_disable; return usb_add_function(c, &dev->function); } static int acc_setup(void) { struct acc_dev *dev; int ret; dev = kzalloc(sizeof(*dev), GFP_KERNEL); if (!dev) return -ENOMEM; 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); /* _acc_dev must be set before calling usb_gadget_register_driver */ _acc_dev = dev; ret = misc_register(&acc_device); if (ret) goto err; return 0; err: kfree(dev); printk(KERN_ERR "USB accessory gadget driver failed to initialize\n"); return ret; } static void acc_cleanup(void) { misc_deregister(&acc_device); kfree(_acc_dev); _acc_dev = NULL; }