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 <andrzej.p@samsung.com>
  11  */
  12
  13 #ifndef __U_F_H__
  14 #define __U_F_H__
  15
  16 #include <linux/usb/gadget.h>
  17
  18 /* Variable Length Array Macros **********************************************/
  19 #define vla_group(groupname) size_t groupname##__next = 0
  20 #define vla_group_size(groupname) groupname##__next
  21
  22 #define vla_item(groupname, type, name, n) \
  23         size_t groupname##_##name##__offset = ({                               \
  24                 size_t align_mask = __alignof__(type) - 1;                     \
  25                 size_t offset = (groupname##__next + align_mask) & ~align_mask;\
  26                 size_t size = (n) * sizeof(type);                              \
  27                 groupname##__next = offset + size;                             \
  28                 offset;                                                        \
  29         })
  30
  31 #define vla_item_with_sz(groupname, type, name, n) \
  32         size_t groupname##_##name##__sz = (n) * sizeof(type);                  \
  33         size_t groupname##_##name##__offset = ({                               \
  34                 size_t align_mask = __alignof__(type) - 1;                     \
  35                 size_t offset = (groupname##__next + align_mask) & ~align_mask;\
  36                 size_t size = groupname##_##name##__sz;                        \
  37                 groupname##__next = offset + size;                             \
  38                 offset;                                                        \
  39         })
  40
  41 #define vla_ptr(ptr, groupname, name) \
  42         ((void *) ((char *)ptr + groupname##_##name##__offset))
  43
  44 struct usb_ep;
  45 struct usb_request;
  46
  47 /**
  48  * alloc_ep_req - returns a usb_request allocated by the gadget driver and
  49  * allocates the request's buffer.
  50  *
  51  * @ep: the endpoint to allocate a usb_request
  52  * @len: usb_requests's buffer suggested size
  53  *
  54  * In case @ep direction is OUT, the @len will be aligned to ep's
  55  * wMaxPacketSize. In order to avoid memory leaks or drops, *always* use
  56  * usb_requests's length (req->length) to refer to the allocated buffer size.
  57  * Requests allocated via alloc_ep_req() *must* be freed by free_ep_req().
  58  */
  59 struct usb_request *alloc_ep_req(struct usb_ep *ep, size_t len);
  60
  61 /* Frees a usb_request previously allocated by alloc_ep_req() */
  62 static inline void free_ep_req(struct usb_ep *ep, struct usb_request *req)
  63 {
  64         WARN_ON(req->buf == NULL);
  65         kfree(req->buf);
  66         req->buf = NULL;
  67         usb_ep_free_request(ep, req);
  68 }
  69
  70 #endif /* __U_F_H__ */