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
  21 /* Variable Length Array Macros **********************************************/
  22 #define vla_group(groupname) size_t groupname##__next = 0
  23 #define vla_group_size(groupname) groupname##__next
  24
  25 #define vla_item(groupname, type, name, n) \
  26         size_t groupname##_##name##__offset = ({                               \
  27                 size_t align_mask = __alignof__(type) - 1;                     \
  28                 size_t offset = (groupname##__next + align_mask) & ~align_mask;\
  29                 size_t size = (n) * sizeof(type);                              \
  30                 groupname##__next = offset + size;                             \
  31                 offset;                                                        \
  32         })
  33
  34 #define vla_item_with_sz(groupname, type, name, n) \
  35         size_t groupname##_##name##__sz = (n) * sizeof(type);                  \
  36         size_t groupname##_##name##__offset = ({                               \
  37                 size_t align_mask = __alignof__(type) - 1;                     \
  38                 size_t offset = (groupname##__next + align_mask) & ~align_mask;\
  39                 size_t size = groupname##_##name##__sz;                        \
  40                 groupname##__next = offset + size;                             \
  41                 offset;                                                        \
  42         })
  43
  44 #define vla_ptr(ptr, groupname, name) \
  45         ((void *) ((char *)ptr + groupname##_##name##__offset))
  46
  47 struct usb_ep;
  48 struct usb_request;
  49
  50 /**
  51  * alloc_ep_req - returns a usb_request allocated by the gadget driver and
  52  * allocates the request's buffer.
  53  *
  54  * @ep: the endpoint to allocate a usb_request
  55  * @len: usb_requests's buffer suggested size
  56  *
  57  * In case @ep direction is OUT, the @len will be aligned to ep's
  58  * wMaxPacketSize. In order to avoid memory leaks or drops, *always* use
  59  * usb_requests's length (req->length) to refer to the allocated buffer size.
  60  * Requests allocated via alloc_ep_req() *must* be freed by free_ep_req().
  61  */
  62 struct usb_request *alloc_ep_req(struct usb_ep *ep, size_t len);
  63
  64 /* Frees a usb_request previously allocated by alloc_ep_req() */
  65 static inline void free_ep_req(struct usb_ep *ep, struct usb_request *req)
  66 {
  67         WARN_ON(req->buf == NULL);
  68         kfree(req->buf);
  69         req->buf = NULL;
  70         usb_ep_free_request(ep, req);
  71 }
  72
  73 #endif /* __U_F_H__ */