1// SPDX-License-Identifier: GPL-2.0
2/*
3 * func_utils.h
4 *
5 * Utility definitions for USB functions
6 *
7 * Copyright (c) 2013 Samsung Electronics Co., Ltd.
8 * http://www.samsung.com
9 *
10 * Author: Andrzej Pietrasiewicz <andrzejtp2010@gmail.com>
11 */
12
13#ifndef _FUNC_UTILS_H_
14#define _FUNC_UTILS_H_
15
16#include <linux/usb/gadget.h>
17#include <linux/overflow.h>
18
19/* Variable Length Array Macros **********************************************/
20#define vla_group(groupname) size_t groupname##__next = 0
21#define vla_group_size(groupname) groupname##__next
22
23#define vla_item(groupname, type, name, n) \
24 size_t groupname##_##name##__offset = ({ \
25 size_t offset = 0; \
26 if (groupname##__next != SIZE_MAX) { \
27 size_t align_mask = __alignof__(type) - 1; \
28 size_t size = array_size(n, sizeof(type)); \
29 offset = (groupname##__next + align_mask) & \
30 ~align_mask; \
31 if (check_add_overflow(offset, size, \
32 &groupname##__next)) { \
33 groupname##__next = SIZE_MAX; \
34 offset = 0; \
35 } \
36 } \
37 offset; \
38 })
39
40#define vla_item_with_sz(groupname, type, name, n) \
41 size_t groupname##_##name##__sz = array_size(n, sizeof(type)); \
42 size_t groupname##_##name##__offset = ({ \
43 size_t offset = 0; \
44 if (groupname##__next != SIZE_MAX) { \
45 size_t align_mask = __alignof__(type) - 1; \
46 offset = (groupname##__next + align_mask) & \
47 ~align_mask; \
48 if (check_add_overflow(offset, groupname##_##name##__sz,\
49 &groupname##__next)) { \
50 groupname##__next = SIZE_MAX; \
51 offset = 0; \
52 } \
53 } \
54 offset; \
55 })
56
57#define vla_ptr(ptr, groupname, name) \
58 ((void *) ((char *)ptr + groupname##_##name##__offset))
59
60struct usb_ep;
61struct usb_request;
62
63/**
64 * alloc_ep_req - returns a usb_request allocated by the gadget driver and
65 * allocates the request's buffer.
66 *
67 * @ep: the endpoint to allocate a usb_request
68 * @len: usb_requests's buffer suggested size
69 *
70 * In case @ep direction is OUT, the @len will be aligned to ep's
71 * wMaxPacketSize. In order to avoid memory leaks or drops, *always* use
72 * usb_requests's length (req->length) to refer to the allocated buffer size.
73 * Requests allocated via alloc_ep_req() *must* be freed by free_ep_req().
74 */
75struct usb_request *alloc_ep_req(struct usb_ep *ep, size_t len);
76
77/* Frees a usb_request previously allocated by alloc_ep_req() */
78static inline void free_ep_req(struct usb_ep *ep, struct usb_request *req)
79{
80 WARN_ON(req->buf == NULL);
81 kfree(objp: req->buf);
82 req->buf = NULL;
83 usb_ep_free_request(ep, req);
84}
85
86#endif /* _FUNC_UTILS_H_ */
87

source code of linux/include/linux/usb/func_utils.h