usb: gadget: Add file for USB HID function

/*

 * f_hid.c -- USB HID function driver

 *

 * Copyright (C) 2010 Fabien Chouteau <fabien.chouteau@barco.com>

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation; either version 2 of the License, or

 * (at your option) any later version.

 */

#include <linux/kernel.h>

#include <linux/module.h>

#include <linux/hid.h>

#include <linux/cdev.h>

#include <linux/mutex.h>

#include <linux/poll.h>

#include <linux/uaccess.h>

#include <linux/wait.h>

#include <linux/sched.h>

#include <linux/usb/g_hid.h>

static int major, minors;

static struct class *hidg_class;

/*-------------------------------------------------------------------------*/

/*                            HID gadget struct                            */

struct f_hidg_req_list {

	struct usb_request	*req;

	unsigned int		pos;

	struct list_head	list;

};

struct f_hidg {

	/* configuration */

	unsigned char			bInterfaceSubClass;

	unsigned char			bInterfaceProtocol;

	unsigned short			report_desc_length;

	char				*report_desc;

	unsigned short			report_length;

	/* recv report */

	struct list_head		completed_out_req;

	spinlock_t			spinlock;

	wait_queue_head_t		read_queue;

	unsigned int			qlen;

	/* send report */

	struct mutex			lock;

	bool				write_pending;

	wait_queue_head_t		write_queue;

	struct usb_request		*req;

	int				minor;

	struct cdev			cdev;

	struct usb_function		func;

	struct usb_ep			*in_ep;

	struct usb_ep			*out_ep;

};

static inline struct f_hidg *func_to_hidg(struct usb_function *f)

{

	return container_of(f, struct f_hidg, func);

}

/*-------------------------------------------------------------------------*/

/*                           Static descriptors                            */

static struct usb_interface_descriptor hidg_interface_desc = {

	.bLength		= sizeof(hidg_interface_desc),

	.bDescriptorType	= USB_DT_INTERFACE,

	/* .bInterfaceNumber	= DYNAMIC */

	.bAlternateSetting	= 0,

	.bNumEndpoints		= 2,

	.bInterfaceClass	= USB_CLASS_HID,

	/* .bInterfaceSubClass	= DYNAMIC */

	/* .bInterfaceProtocol	= DYNAMIC */

	/* .iInterface		= DYNAMIC */

};

static struct hid_descriptor hidg_desc = {

	.bLength			= sizeof(hidg_desc),

	.bDescriptorType		= HID_DT_HID,

	.bcdHID				= 0x0101,

	.bCountryCode			= 0x00,

	.bNumDescriptors		= 0x1,

	/*.desc[0].bDescriptorType	= DYNAMIC */

	/*.desc[0].wDescriptorLenght	= DYNAMIC */

};

/* High-Speed Support */

static struct usb_endpoint_descriptor hidg_hs_in_ep_desc = {

	.bLength		= USB_DT_ENDPOINT_SIZE,

	.bDescriptorType	= USB_DT_ENDPOINT,

	.bEndpointAddress	= USB_DIR_IN,

	.bmAttributes		= USB_ENDPOINT_XFER_INT,

	/*.wMaxPacketSize	= DYNAMIC */

	.bInterval		= 4, /* FIXME: Add this field in the

				      * HID gadget configuration?

				      * (struct hidg_func_descriptor)

				      */

};

static struct usb_endpoint_descriptor hidg_hs_out_ep_desc = {

	.bLength		= USB_DT_ENDPOINT_SIZE,

	.bDescriptorType	= USB_DT_ENDPOINT,

	.bEndpointAddress	= USB_DIR_OUT,

	.bmAttributes		= USB_ENDPOINT_XFER_INT,

	/*.wMaxPacketSize	= DYNAMIC */

	.bInterval		= 4, /* FIXME: Add this field in the

				      * HID gadget configuration?

				      * (struct hidg_func_descriptor)

				      */

};

static struct usb_descriptor_header *hidg_hs_descriptors[] = {

	(struct usb_descriptor_header *)&hidg_interface_desc,

	(struct usb_descriptor_header *)&hidg_desc,

	(struct usb_descriptor_header *)&hidg_hs_in_ep_desc,

	(struct usb_descriptor_header *)&hidg_hs_out_ep_desc,

	NULL,

};

/* Full-Speed Support */

static struct usb_endpoint_descriptor hidg_fs_in_ep_desc = {

	.bLength		= USB_DT_ENDPOINT_SIZE,

	.bDescriptorType	= USB_DT_ENDPOINT,

	.bEndpointAddress	= USB_DIR_IN,

	.bmAttributes		= USB_ENDPOINT_XFER_INT,

	/*.wMaxPacketSize	= DYNAMIC */

	.bInterval		= 10, /* FIXME: Add this field in the

				       * HID gadget configuration?

				       * (struct hidg_func_descriptor)

				       */

};

static struct usb_endpoint_descriptor hidg_fs_out_ep_desc = {

	.bLength		= USB_DT_ENDPOINT_SIZE,

	.bDescriptorType	= USB_DT_ENDPOINT,

	.bEndpointAddress	= USB_DIR_OUT,

	.bmAttributes		= USB_ENDPOINT_XFER_INT,

	/*.wMaxPacketSize	= DYNAMIC */

	.bInterval		= 10, /* FIXME: Add this field in the

				       * HID gadget configuration?

				       * (struct hidg_func_descriptor)

				       */

};

static struct usb_descriptor_header *hidg_fs_descriptors[] = {

	(struct usb_descriptor_header *)&hidg_interface_desc,

	(struct usb_descriptor_header *)&hidg_desc,

	(struct usb_descriptor_header *)&hidg_fs_in_ep_desc,

	(struct usb_descriptor_header *)&hidg_fs_out_ep_desc,

	NULL,

};

/*-------------------------------------------------------------------------*/

/*                              Char Device                                */

static ssize_t f_hidg_read(struct file *file, char __user *buffer,

			size_t count, loff_t *ptr)

{

	struct f_hidg *hidg = file->private_data;

	struct f_hidg_req_list *list;

	struct usb_request *req;

	unsigned long flags;

	int ret;

	if (!count)

		return 0;

	if (!access_ok(VERIFY_WRITE, buffer, count))

		return -EFAULT;

	spin_lock_irqsave(&hidg->spinlock, flags);

#define READ_COND (!list_empty(&hidg->completed_out_req))

	/* wait for at least one buffer to complete */

	while (!READ_COND) {

		spin_unlock_irqrestore(&hidg->spinlock, flags);

		if (file->f_flags & O_NONBLOCK)

			return -EAGAIN;

		if (wait_event_interruptible(hidg->read_queue, READ_COND))

			return -ERESTARTSYS;

		spin_lock_irqsave(&hidg->spinlock, flags);

	}

	/* pick the first one */

	list = list_first_entry(&hidg->completed_out_req,

				struct f_hidg_req_list, list);

	req = list->req;

	count = min_t(unsigned int, count, req->actual - list->pos);

	spin_unlock_irqrestore(&hidg->spinlock, flags);

	/* copy to user outside spinlock */

	count -= copy_to_user(buffer, req->buf + list->pos, count);

	list->pos += count;

	/*

	 * if this request is completely handled and transfered to

	 * userspace, remove its entry from the list and requeue it

	 * again. Otherwise, we will revisit it again upon the next

	 * call, taking into account its current read position.

	 */

	if (list->pos == req->actual) {

		spin_lock_irqsave(&hidg->spinlock, flags);

		list_del(&list->list);

		kfree(list);

		spin_unlock_irqrestore(&hidg->spinlock, flags);

		req->length = hidg->report_length;

		ret = usb_ep_queue(hidg->out_ep, req, GFP_KERNEL);

		if (ret < 0)

			return ret;

	}

	return count;

}

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

{

	struct f_hidg *hidg = (struct f_hidg *)ep->driver_data;

	if (req->status != 0) {

		ERROR(hidg->func.config->cdev,

			"End Point Request ERROR: %d\n", req->status);

	}

	hidg->write_pending = 0;

	wake_up(&hidg->write_queue);

}

static ssize_t f_hidg_write(struct file *file, const char __user *buffer,

			    size_t count, loff_t *offp)

{

	struct f_hidg *hidg  = file->private_data;

	ssize_t status = -ENOMEM;

	if (!access_ok(VERIFY_READ, buffer, count))

		return -EFAULT;

	mutex_lock(&hidg->lock);

#define WRITE_COND (!hidg->write_pending)

	/* write queue */

	while (!WRITE_COND) {

		mutex_unlock(&hidg->lock);

		if (file->f_flags & O_NONBLOCK)

			return -EAGAIN;

		if (wait_event_interruptible_exclusive(

				hidg->write_queue, WRITE_COND))

			return -ERESTARTSYS;

		mutex_lock(&hidg->lock);

	}

	count  = min_t(unsigned, count, hidg->report_length);

	status = copy_from_user(hidg->req->buf, buffer, count);

	if (status != 0) {

		ERROR(hidg->func.config->cdev,

			"copy_from_user error\n");

		mutex_unlock(&hidg->lock);

		return -EINVAL;

	}

	hidg->req->status   = 0;

	hidg->req->zero     = 0;

	hidg->req->length   = count;

	hidg->req->complete = f_hidg_req_complete;

	hidg->req->context  = hidg;

	hidg->write_pending = 1;

	status = usb_ep_queue(hidg->in_ep, hidg->req, GFP_ATOMIC);

	if (status < 0) {

		ERROR(hidg->func.config->cdev,

			"usb_ep_queue error on int endpoint %zd\n", status);

		hidg->write_pending = 0;

		wake_up(&hidg->write_queue);

	} else {

		status = count;

	}

	mutex_unlock(&hidg->lock);

	return status;

}

static unsigned int f_hidg_poll(struct file *file, poll_table *wait)

{

	struct f_hidg	*hidg  = file->private_data;

	unsigned int	ret = 0;

	poll_wait(file, &hidg->read_queue, wait);

	poll_wait(file, &hidg->write_queue, wait);

	if (WRITE_COND)

		ret |= POLLOUT | POLLWRNORM;

	if (READ_COND)

		ret |= POLLIN | POLLRDNORM;

	return ret;

}

#undef WRITE_COND

#undef READ_COND

static int f_hidg_release(struct inode *inode, struct file *fd)

{

	fd->private_data = NULL;

	return 0;

}

static int f_hidg_open(struct inode *inode, struct file *fd)

{

	struct f_hidg *hidg =

		container_of(inode->i_cdev, struct f_hidg, cdev);

	fd->private_data = hidg;

	return 0;

}

/*-------------------------------------------------------------------------*/

/*                                usb_function                             */

static struct usb_request *hidg_alloc_ep_req(struct usb_ep *ep, unsigned length)

{

	struct usb_request *req;

	req = usb_ep_alloc_request(ep, GFP_ATOMIC);

	if (req) {

		req->length = length;

		req->buf = kmalloc(length, GFP_ATOMIC);

		if (!req->buf) {

			usb_ep_free_request(ep, req);

			req = NULL;

		}

	}

	return req;

}

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

{

	struct f_hidg *hidg = (struct f_hidg *) req->context;

	struct f_hidg_req_list *req_list;

	unsigned long flags;

	req_list = kzalloc(sizeof(*req_list), GFP_ATOMIC);

	if (!req_list)

		return;

	req_list->req = req;

	spin_lock_irqsave(&hidg->spinlock, flags);

	list_add_tail(&req_list->list, &hidg->completed_out_req);

	spin_unlock_irqrestore(&hidg->spinlock, flags);

	wake_up(&hidg->read_queue);

}

static int hidg_setup(struct usb_function *f,

		const struct usb_ctrlrequest *ctrl)

{

	struct f_hidg			*hidg = func_to_hidg(f);

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

	struct usb_request		*req  = cdev->req;

	int status = 0;

	__u16 value, length;

	value	= __le16_to_cpu(ctrl->wValue);

	length	= __le16_to_cpu(ctrl->wLength);

	VDBG(cdev,

		"hid_setup crtl_request : bRequestType:0x%x bRequest:0x%x Value:0x%x\n",

		ctrl->bRequestType, ctrl->bRequest, value);

	switch ((ctrl->bRequestType << 8) | ctrl->bRequest) {

	case ((USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8

		  | HID_REQ_GET_REPORT):

		VDBG(cdev, "get_report\n");

		/* send an empty report */

		length = min_t(unsigned, length, hidg->report_length);

		memset(req->buf, 0x0, length);

		goto respond;

		break;

	case ((USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8

		  | HID_REQ_GET_PROTOCOL):

		VDBG(cdev, "get_protocol\n");

		goto stall;

		break;

	case ((USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8

		  | HID_REQ_SET_REPORT):

		VDBG(cdev, "set_report | wLenght=%d\n", ctrl->wLength);

		goto stall;

		break;

	case ((USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8

		  | HID_REQ_SET_PROTOCOL):

		VDBG(cdev, "set_protocol\n");

		goto stall;

		break;

	case ((USB_DIR_IN | USB_TYPE_STANDARD | USB_RECIP_INTERFACE) << 8

		  | USB_REQ_GET_DESCRIPTOR):

		switch (value >> 8) {

		case HID_DT_HID:

			VDBG(cdev, "USB_REQ_GET_DESCRIPTOR: HID\n");

			length = min_t(unsigned short, length,

						   hidg_desc.bLength);

			memcpy(req->buf, &hidg_desc, length);

			goto respond;

			break;

		case HID_DT_REPORT:

			VDBG(cdev, "USB_REQ_GET_DESCRIPTOR: REPORT\n");

			length = min_t(unsigned short, length,

						   hidg->report_desc_length);

			memcpy(req->buf, hidg->report_desc, length);

			goto respond;

			break;

		default:

			VDBG(cdev, "Unknown descriptor request 0x%x\n",

				 value >> 8);

			goto stall;

			break;

		}

		break;

	default:

		VDBG(cdev, "Unknown request 0x%x\n",

			 ctrl->bRequest);

		goto stall;

		break;

	}

stall:

	return -EOPNOTSUPP;

respond:

	req->zero = 0;

	req->length = length;

	status = usb_ep_queue(cdev->gadget->ep0, req, GFP_ATOMIC);

	if (status < 0)

		ERROR(cdev, "usb_ep_queue error on ep0 %d\n", value);

	return status;

}

static void hidg_disable(struct usb_function *f)

{

	struct f_hidg *hidg = func_to_hidg(f);

	struct f_hidg_req_list *list, *next;

	usb_ep_disable(hidg->in_ep);

	hidg->in_ep->driver_data = NULL;

	usb_ep_disable(hidg->out_ep);

	hidg->out_ep->driver_data = NULL;

	list_for_each_entry_safe(list, next, &hidg->completed_out_req, list) {

		list_del(&list->list);

		kfree(list);

	}

}

static int hidg_set_alt(struct usb_function *f, unsigned intf, unsigned alt)

{

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

	struct f_hidg				*hidg = func_to_hidg(f);

	int i, status = 0;

	VDBG(cdev, "hidg_set_alt intf:%d alt:%d\n", intf, alt);

	if (hidg->in_ep != NULL) {

		/* restart endpoint */

		if (hidg->in_ep->driver_data != NULL)

			usb_ep_disable(hidg->in_ep);

		status = config_ep_by_speed(f->config->cdev->gadget, f,

					    hidg->in_ep);

		if (status) {

			ERROR(cdev, "config_ep_by_speed FAILED!\n");

			goto fail;

		}

		status = usb_ep_enable(hidg->in_ep);

		if (status < 0) {

			ERROR(cdev, "Enable IN endpoint FAILED!\n");

			goto fail;

		}

		hidg->in_ep->driver_data = hidg;

	}

	if (hidg->out_ep != NULL) {

		/* restart endpoint */

		if (hidg->out_ep->driver_data != NULL)

			usb_ep_disable(hidg->out_ep);

		status = config_ep_by_speed(f->config->cdev->gadget, f,

					    hidg->out_ep);

		if (status) {

			ERROR(cdev, "config_ep_by_speed FAILED!\n");

			goto fail;

		}

		status = usb_ep_enable(hidg->out_ep);

		if (status < 0) {

			ERROR(cdev, "Enable IN endpoint FAILED!\n");

			goto fail;

		}

		hidg->out_ep->driver_data = hidg;

		/*

		 * allocate a bunch of read buffers and queue them all at once.

		 */

		for (i = 0; i < hidg->qlen && status == 0; i++) {

			struct usb_request *req =

					hidg_alloc_ep_req(hidg->out_ep,

							  hidg->report_length);

			if (req) {

				req->complete = hidg_set_report_complete;

				req->context  = hidg;

				status = usb_ep_queue(hidg->out_ep, req,

						      GFP_ATOMIC);

				if (status)

					ERROR(cdev, "%s queue req --> %d\n",

						hidg->out_ep->name, status);

			} else {

				usb_ep_disable(hidg->out_ep);

				hidg->out_ep->driver_data = NULL;

				status = -ENOMEM;

				goto fail;

			}

		}

	}

fail:

	return status;

}

const struct file_operations f_hidg_fops = {

	.owner		= THIS_MODULE,

	.open		= f_hidg_open,

	.release	= f_hidg_release,

	.write		= f_hidg_write,

	.read		= f_hidg_read,

	.poll		= f_hidg_poll,

	.llseek		= noop_llseek,

};

static int __init hidg_bind(struct usb_configuration *c, struct usb_function *f)

{

	struct usb_ep		*ep;

	struct f_hidg		*hidg = func_to_hidg(f);

	int			status;

	dev_t			dev;

	/* allocate instance-specific interface IDs, and patch descriptors */

	status = usb_interface_id(c, f);

	if (status < 0)

		goto fail;

	hidg_interface_desc.bInterfaceNumber = status;

	/* allocate instance-specific endpoints */

	status = -ENODEV;

	ep = usb_ep_autoconfig(c->cdev->gadget, &hidg_fs_in_ep_desc);

	if (!ep)

		goto fail;

	ep->driver_data = c->cdev;	/* claim */

	hidg->in_ep = ep;

	ep = usb_ep_autoconfig(c->cdev->gadget, &hidg_fs_out_ep_desc);

	if (!ep)

		goto fail;

	ep->driver_data = c->cdev;	/* claim */

	hidg->out_ep = ep;

	/* preallocate request and buffer */

	status = -ENOMEM;

	hidg->req = usb_ep_alloc_request(hidg->in_ep, GFP_KERNEL);

	if (!hidg->req)

		goto fail;

	hidg->req->buf = kmalloc(hidg->report_length, GFP_KERNEL);

	if (!hidg->req->buf)

		goto fail;

	/* set descriptor dynamic values */

	hidg_interface_desc.bInterfaceSubClass = hidg->bInterfaceSubClass;

	hidg_interface_desc.bInterfaceProtocol = hidg->bInterfaceProtocol;

	hidg_hs_in_ep_desc.wMaxPacketSize = cpu_to_le16(hidg->report_length);

	hidg_fs_in_ep_desc.wMaxPacketSize = cpu_to_le16(hidg->report_length);

	hidg_hs_out_ep_desc.wMaxPacketSize = cpu_to_le16(hidg->report_length);

	hidg_fs_out_ep_desc.wMaxPacketSize = cpu_to_le16(hidg->report_length);

	hidg_desc.desc[0].bDescriptorType = HID_DT_REPORT;

	hidg_desc.desc[0].wDescriptorLength =

		cpu_to_le16(hidg->report_desc_length);

	hidg_hs_in_ep_desc.bEndpointAddress =

		hidg_fs_in_ep_desc.bEndpointAddress;

	hidg_hs_out_ep_desc.bEndpointAddress =

		hidg_fs_out_ep_desc.bEndpointAddress;

	status = usb_assign_descriptors(f, hidg_fs_descriptors,

			hidg_hs_descriptors, NULL);

	if (status)

		goto fail;

	mutex_init(&hidg->lock);

	spin_lock_init(&hidg->spinlock);

	init_waitqueue_head(&hidg->write_queue);

	init_waitqueue_head(&hidg->read_queue);

	INIT_LIST_HEAD(&hidg->completed_out_req);

	/* create char device */

	cdev_init(&hidg->cdev, &f_hidg_fops);

	dev = MKDEV(major, hidg->minor);

	status = cdev_add(&hidg->cdev, dev, 1);

	if (status)

		goto fail;

	device_create(hidg_class, NULL, dev, NULL, "%s%d", "hidg", hidg->minor);

	return 0;

fail:

	ERROR(f->config->cdev, "hidg_bind FAILED\n");

	if (hidg->req != NULL) {

		kfree(hidg->req->buf);

		if (hidg->in_ep != NULL)

			usb_ep_free_request(hidg->in_ep, hidg->req);

	}

	usb_free_all_descriptors(f);

	return status;

}

static void hidg_unbind(struct usb_configuration *c, struct usb_function *f)

{

	struct f_hidg *hidg = func_to_hidg(f);

	device_destroy(hidg_class, MKDEV(major, hidg->minor));

	cdev_del(&hidg->cdev);

	/* disable/free request and end point */

	usb_ep_disable(hidg->in_ep);

	usb_ep_dequeue(hidg->in_ep, hidg->req);

	kfree(hidg->req->buf);

	usb_ep_free_request(hidg->in_ep, hidg->req);

	usb_free_all_descriptors(f);

	kfree(hidg->report_desc);

	kfree(hidg);

}

/*-------------------------------------------------------------------------*/

/*                                 Strings                                 */

#define CT_FUNC_HID_IDX	0

static struct usb_string ct_func_string_defs[] = {

	[CT_FUNC_HID_IDX].s	= "HID Interface",

	{},			/* end of list */

};

static struct usb_gadget_strings ct_func_string_table = {

	.language	= 0x0409,	/* en-US */

	.strings	= ct_func_string_defs,

};

static struct usb_gadget_strings *ct_func_strings[] = {

	&ct_func_string_table,

	NULL,

};

/*-------------------------------------------------------------------------*/

/*                             usb_configuration                           */

int __init hidg_bind_config(struct usb_configuration *c,

			    struct hidg_func_descriptor *fdesc, int index)

{

	struct f_hidg *hidg;

	int status;