drivers/usb/gadget/u_f.h

   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
  60 struct usb_ep;
  61 struct 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  */
  75 struct usb_request *alloc_ep_req(struct usb_ep *ep, size_t len);
  76
  77 /* Frees a usb_request previously allocated by alloc_ep_req() */
  78 static 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__ */