drivers/usb/gadget/u_f.h

   1 /*
   2  * u_f.h
   3  *
   4  * Utility definitions for USB functions
   5  *
   6  * Copyright (c) 2013 Samsung Electronics Co., Ltd.
   7  *              http://www.samsung.com
   8  *
   9  * Author: Andrzej Pietrasiewicz <andrzej.p@samsung.com>
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License version 2 as
  13  * published by the Free Software Foundation.
  14  */
  15
  16 #ifndef __U_F_H__
  17 #define __U_F_H__
  18
  19 #include <linux/usb/gadget.h>
  20 #include <linux/overflow.h>
  21
  22 /* Variable Length Array Macros **********************************************/
  23 #define vla_group(groupname) size_t groupname##__next = 0
  24 #define vla_group_size(groupname) groupname##__next
  25
  26 #define vla_item(groupname, type, name, n) \
  27         size_t groupname##_##name##__offset = ({                               \
  28                 size_t offset = 0;                                             \
  29                 if (groupname##__next != SIZE_MAX) {                           \
  30                         size_t align_mask = __alignof__(type) - 1;             \
  31                         size_t size = array_size(n, sizeof(type));             \
  32                         offset = (groupname##__next + align_mask) &            \
  33                                   ~align_mask;                                 \
  34                         if (check_add_overflow(offset, size,                   \
  35                                                &groupname##__next)) {          \
  36                                 groupname##__next = SIZE_MAX;                  \
  37                                 offset = 0;                                    \
  38                         }                                                      \
  39                 }                                                              \
  40                 offset;                                                        \
  41         })
  42
  43 #define vla_item_with_sz(groupname, type, name, n) \
  44         size_t groupname##_##name##__sz = array_size(n, sizeof(type));          \
  45         size_t groupname##_##name##__offset = ({                                \
  46                 size_t offset = 0;                                              \
  47                 if (groupname##__next != SIZE_MAX) {                            \
  48                         size_t align_mask = __alignof__(type) - 1;              \
  49                         offset = (groupname##__next + align_mask) &             \
  50                                   ~align_mask;                                  \
  51                         if (check_add_overflow(offset, groupname##_##name##__sz,\
  52                                                         &groupname##__next)) {  \
  53                                 groupname##__next = SIZE_MAX;                   \
  54                                 offset = 0;                                     \
  55                         }                                                       \
  56                 }                                                               \
  57                 offset;                                                         \
  58         })
  59
  60 #define vla_ptr(ptr, groupname, name) \
  61         ((void *) ((char *)ptr + groupname##_##name##__offset))
  62
  63 struct usb_ep;
  64 struct usb_request;
  65
  66 /**
  67  * alloc_ep_req - returns a usb_request allocated by the gadget driver and
  68  * allocates the request's buffer.
  69  *
  70  * @ep: the endpoint to allocate a usb_request
  71  * @len: usb_requests's buffer suggested size
  72  *
  73  * In case @ep direction is OUT, the @len will be aligned to ep's
  74  * wMaxPacketSize. In order to avoid memory leaks or drops, *always* use
  75  * usb_requests's length (req->length) to refer to the allocated buffer size.
  76  * Requests allocated via alloc_ep_req() *must* be freed by free_ep_req().
  77  */
  78 struct usb_request *alloc_ep_req(struct usb_ep *ep, size_t len);
  79
  80 /* Frees a usb_request previously allocated by alloc_ep_req() */
  81 static inline void free_ep_req(struct usb_ep *ep, struct usb_request *req)
  82 {
  83         WARN_ON(req->buf == NULL);
  84         kfree(req->buf);
  85         req->buf = NULL;
  86         usb_ep_free_request(ep, req);
  87 }
  88
  89 #endif /* __U_F_H__ */