usb: gadget: adb: Add ADB function

/*

 * Gadget Driver for Android ADB

 *

 * Copyright (C) 2008 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.

 *

 */

#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/sched.h>

#include <linux/types.h>

#include <linux/device.h>

#include <linux/miscdevice.h>

#define ADB_BULK_BUFFER_SIZE           4096

/* number of tx requests to allocate */

#define TX_REQ_MAX 4

static const char adb_shortname[] = "android_adb";

struct adb_dev {

	struct usb_function function;

	struct usb_composite_dev *cdev;

	spinlock_t lock;

	struct usb_ep *ep_in;

	struct usb_ep *ep_out;

	int online;

	int error;

	atomic_t read_excl;

	atomic_t write_excl;

	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;

	int rx_done;

};

static struct usb_interface_descriptor adb_interface_desc = {

	.bLength                = USB_DT_INTERFACE_SIZE,

	.bDescriptorType        = USB_DT_INTERFACE,

	.bInterfaceNumber       = 0,

	.bNumEndpoints          = 2,

	.bInterfaceClass        = 0xFF,

	.bInterfaceSubClass     = 0x42,

	.bInterfaceProtocol     = 1,

};

static struct usb_endpoint_descriptor adb_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 adb_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 adb_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 adb_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_adb_descs[] = {

	(struct usb_descriptor_header *) &adb_interface_desc,

	(struct usb_descriptor_header *) &adb_fullspeed_in_desc,

	(struct usb_descriptor_header *) &adb_fullspeed_out_desc,

	NULL,

};

static struct usb_descriptor_header *hs_adb_descs[] = {

	(struct usb_descriptor_header *) &adb_interface_desc,

	(struct usb_descriptor_header *) &adb_highspeed_in_desc,

	(struct usb_descriptor_header *) &adb_highspeed_out_desc,

	NULL,

};

/* temporary variable used between adb_open() and adb_gadget_bind() */

static struct adb_dev *_adb_dev;

static inline struct adb_dev *func_to_adb(struct usb_function *f)

{

	return container_of(f, struct adb_dev, function);

}

static struct usb_request *adb_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 adb_request_free(struct usb_request *req, struct usb_ep *ep)

{

	if (req) {

		kfree(req->buf);

		usb_ep_free_request(ep, req);

	}

}

static inline int adb_lock(atomic_t *excl)

{

	if (atomic_inc_return(excl) == 1) {

		return 0;

	} else {

		atomic_dec(excl);

		return -1;

	}

}

static inline void adb_unlock(atomic_t *excl)

{

	atomic_dec(excl);

}

/* add a request to the tail of a list */

void adb_req_put(struct adb_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 */

struct usb_request *adb_req_get(struct adb_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 adb_complete_in(struct usb_ep *ep, struct usb_request *req)

{

	struct adb_dev *dev = _adb_dev;

	if (req->status != 0)

		dev->error = 1;

	adb_req_put(dev, &dev->tx_idle, req);

	wake_up(&dev->write_wq);

}

static void adb_complete_out(struct usb_ep *ep, struct usb_request *req)

{

	struct adb_dev *dev = _adb_dev;

	dev->rx_done = 1;

	if (req->status != 0)

		dev->error = 1;

	wake_up(&dev->read_wq);

}

static int adb_create_bulk_endpoints(struct adb_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 adb ep_out got %s\n", ep->name);

	ep->driver_data = dev;		/* claim the endpoint */

	dev->ep_out = ep;

	/* now allocate requests for our endpoints */

	req = adb_request_new(dev->ep_out, ADB_BULK_BUFFER_SIZE);

	if (!req)

		goto fail;

	req->complete = adb_complete_out;

	dev->rx_req = req;

	for (i = 0; i < TX_REQ_MAX; i++) {

		req = adb_request_new(dev->ep_in, ADB_BULK_BUFFER_SIZE);

		if (!req)

			goto fail;

		req->complete = adb_complete_in;

		adb_req_put(dev, &dev->tx_idle, req);

	}

	return 0;

fail:

	printk(KERN_ERR "adb_bind() could not allocate requests\n");

	return -1;

}

static ssize_t adb_read(struct file *fp, char __user *buf,

				size_t count, loff_t *pos)

{

	struct adb_dev *dev = fp->private_data;

	struct usb_request *req;

	int r = count, xfer;

	int ret;

	pr_debug("adb_read(%d)\n", count);

	if (!_adb_dev)

		return -ENODEV;

	if (count > ADB_BULK_BUFFER_SIZE)

		return -EINVAL;

	if (adb_lock(&dev->read_excl))

		return -EBUSY;

	/* we will block until we're online */

	while (!(dev->online || dev->error)) {

		pr_debug("adb_read: waiting for online state\n");

		ret = wait_event_interruptible(dev->read_wq,

				(dev->online || dev->error));

		if (ret < 0) {

			adb_unlock(&dev->read_excl);

			return ret;

		}

	}

	if (dev->error) {

		r = -EIO;

		goto done;

	}

requeue_req:

	/* queue a request */

	req = dev->rx_req;

	req->length = count;

	dev->rx_done = 0;

	ret = usb_ep_queue(dev->ep_out, req, GFP_ATOMIC);

	if (ret < 0) {

		pr_debug("adb_read: failed to queue req %p (%d)\n", req, ret);

		r = -EIO;

		dev->error = 1;

		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) {

		dev->error = 1;

		r = ret;

		usb_ep_dequeue(dev->ep_out, req);

		goto done;

	}

	if (!dev->error) {

		/* 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;

		if (copy_to_user(buf, req->buf, xfer))

			r = -EFAULT;

	} else

		r = -EIO;

done:

	adb_unlock(&dev->read_excl);

	pr_debug("adb_read returning %d\n", r);

	return r;

}

static ssize_t adb_write(struct file *fp, const char __user *buf,

				 size_t count, loff_t *pos)

{

	struct adb_dev *dev = fp->private_data;

	struct usb_request *req = 0;

	int r = count, xfer;

	int ret;

	if (!_adb_dev)

		return -ENODEV;

	pr_debug("adb_write(%d)\n", count);

	if (adb_lock(&dev->write_excl))

		return -EBUSY;

	while (count > 0) {

		if (dev->error) {

			pr_debug("adb_write dev->error\n");

			r = -EIO;

			break;

		}

		/* get an idle tx request to use */

		req = 0;

		ret = wait_event_interruptible(dev->write_wq,

			(req = adb_req_get(dev, &dev->tx_idle)) || dev->error);

		if (ret < 0) {

			r = ret;

			break;

		}

		if (req != 0) {

			if (count > ADB_BULK_BUFFER_SIZE)

				xfer = ADB_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_ATOMIC);

			if (ret < 0) {

				pr_debug("adb_write: xfer error %d\n", ret);

				dev->error = 1;

				r = -EIO;

				break;

			}

			buf += xfer;

			count -= xfer;

			/* zero this so we don't try to free it on error exit */

			req = 0;

		}

	}

	if (req)

		adb_req_put(dev, &dev->tx_idle, req);

	adb_unlock(&dev->write_excl);

	pr_debug("adb_write returning %d\n", r);

	return r;

}

static int adb_open(struct inode *ip, struct file *fp)

{

	printk(KERN_INFO "adb_open\n");

	if (!_adb_dev)

		return -ENODEV;

	if (adb_lock(&_adb_dev->open_excl))

		return -EBUSY;

	fp->private_data = _adb_dev;

	/* clear the error latch */

	_adb_dev->error = 0;

	return 0;

}

static int adb_release(struct inode *ip, struct file *fp)

{

	printk(KERN_INFO "adb_release\n");

	adb_unlock(&_adb_dev->open_excl);

	return 0;

}

/* file operations for ADB device /dev/android_adb */

static const struct file_operations adb_fops = {

	.owner = THIS_MODULE,

	.read = adb_read,

	.write = adb_write,

	.open = adb_open,

	.release = adb_release,

};

static struct miscdevice adb_device = {

	.minor = MISC_DYNAMIC_MINOR,

	.name = adb_shortname,

	.fops = &adb_fops,

};

static int

adb_function_bind(struct usb_configuration *c, struct usb_function *f)

{

	struct usb_composite_dev *cdev = c->cdev;

	struct adb_dev	*dev = func_to_adb(f);

	int			id;

	int			ret;

	dev->cdev = cdev;

	DBG(cdev, "adb_function_bind dev: %p\n", dev);

	/* allocate interface ID(s) */

	id = usb_interface_id(c, f);

	if (id < 0)

		return id;

	adb_interface_desc.bInterfaceNumber = id;

	/* allocate endpoints */

	ret = adb_create_bulk_endpoints(dev, &adb_fullspeed_in_desc,

			&adb_fullspeed_out_desc);

	if (ret)

		return ret;

	/* support high speed hardware */

	if (gadget_is_dualspeed(c->cdev->gadget)) {

		adb_highspeed_in_desc.bEndpointAddress =

			adb_fullspeed_in_desc.bEndpointAddress;

		adb_highspeed_out_desc.bEndpointAddress =

			adb_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

adb_function_unbind(struct usb_configuration *c, struct usb_function *f)

{

	struct adb_dev	*dev = func_to_adb(f);

	struct usb_request *req;

	dev->online = 0;

	dev->error = 1;

	wake_up(&dev->read_wq);

	adb_request_free(dev->rx_req, dev->ep_out);

	while ((req = adb_req_get(dev, &dev->tx_idle)))

		adb_request_free(req, dev->ep_in);

}

static int adb_function_set_alt(struct usb_function *f,

		unsigned intf, unsigned alt)

{

	struct adb_dev	*dev = func_to_adb(f);

	struct usb_composite_dev *cdev = f->config->cdev;

	int ret;

	DBG(cdev, "adb_function_set_alt intf: %d alt: %d\n", intf, alt);

	ret = config_ep_by_speed(cdev->gadget, f, dev->ep_in);

	if (ret)

		return ret;

	ret = usb_ep_enable(dev->ep_in);

	if (ret)

		return ret;

	ret = config_ep_by_speed(cdev->gadget, f, dev->ep_out);

	if (ret)

		return ret;

	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 adb_function_disable(struct usb_function *f)

{

	struct adb_dev	*dev = func_to_adb(f);

	struct usb_composite_dev	*cdev = dev->cdev;

	DBG(cdev, "adb_function_disable cdev %p\n", cdev);

	dev->online = 0;

	dev->error = 1;

	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 adb_bind_config(struct usb_configuration *c)

{

	struct adb_dev *dev = _adb_dev;

	printk(KERN_INFO "adb_bind_config\n");

	dev->cdev = c->cdev;

	dev->function.name = "adb";

	dev->function.descriptors = fs_adb_descs;

	dev->function.hs_descriptors = hs_adb_descs;

	dev->function.bind = adb_function_bind;

	dev->function.unbind = adb_function_unbind;

	dev->function.set_alt = adb_function_set_alt;

	dev->function.disable = adb_function_disable;

	return usb_add_function(c, &dev->function);

}

static int adb_setup(void)

{

	struct adb_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);

	atomic_set(&dev->read_excl, 0);

	atomic_set(&dev->write_excl, 0);

	INIT_LIST_HEAD(&dev->tx_idle);

	_adb_dev = dev;

	ret = misc_register(&adb_device);

	if (ret)

		goto err;

	return 0;

err:

	kfree(dev);

	printk(KERN_ERR "adb gadget driver failed to initialize\n");

	return ret;

}

static void adb_cleanup(void)

{

	misc_deregister(&adb_device);

	kfree(_adb_dev);

	_adb_dev = NULL;

}