path: root/drivers/usb/gadget/function/f_hid.c

// SPDX-License-Identifier: GPL-2.0+
/*
 * f_hid.c -- USB HID function driver
 *
 * Copyright (C) 2010 Fabien Chouteau <fabien.chouteau@barco.com>
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/hid.h>
#include <linux/idr.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>

#include "u_f.h"
#include "u_hid.h"

#define HIDG_MINORS	4

static int major, minors;
static struct class *hidg_class;
static DEFINE_IDA(hidg_ida);
static DEFINE_MUTEX(hidg_ida_lock); /* protects access to hidg_ida */

/*-------------------------------------------------------------------------*/
/*                            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 char			protocol;
	unsigned short			report_desc_length;
	char				*report_desc;
	unsigned short			report_length;

	/* recv report */
	struct list_head		completed_out_req;
	spinlock_t			read_spinlock;
	wait_queue_head_t		read_queue;
	unsigned int			qlen;

	/* send report */
	spinlock_t			write_spinlock;
	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 */
};

/* Super-Speed Support */

static struct usb_endpoint_descriptor hidg_ss_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_ss_ep_comp_descriptor hidg_ss_in_comp_desc = {
	.bLength                = sizeof(hidg_ss_in_comp_desc),
	.bDescriptorType        = USB_DT_SS_ENDPOINT_COMP,

	/* .bMaxBurst           = 0, */
	/* .bmAttributes        = 0, */
	/* .wBytesPerInterval   = DYNAMIC */
};

static struct usb_endpoint_descriptor hidg_ss_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_ss_ep_comp_descriptor hidg_ss_out_comp_desc = {
	.bLength                = sizeof(hidg_ss_out_comp_desc),
	.bDescriptorType        = USB_DT_SS_ENDPOINT_COMP,

	/* .bMaxBurst           = 0, */
	/* .bmAttributes        = 0, */
	/* .wBytesPerInterval   = DYNAMIC */
};

static struct usb_descriptor_header *hidg_ss_descriptors[] = {
	(struct usb_descriptor_header *)&hidg_interface_desc,
	(struct usb_descriptor_header *)&hidg_desc,
	(struct usb_descriptor_header *)&hidg_ss_in_ep_desc,
	(struct usb_descriptor_header *)&hidg_ss_in_comp_desc,
	(struct usb_descriptor_header *)&hidg_ss_out_ep_desc,
	(struct usb_descriptor_header *)&hidg_ss_out_comp_desc,
	NULL,
};

/* 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