LXR linux/drivers/usb/gadget/u

   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * u_f.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 __U_F_H__
  14#define __U_F_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(req->buf);
  82        req->buf = NULL;
  83        usb_ep_free_request(ep, req);
  84}
  85
  86#endif /* __U_F_H__ */
  87