xref: /openbmc/linux/drivers/usb/gadget/u_f.h (revision 1c2dd16a)
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 	kfree(req->buf);
68 	usb_ep_free_request(ep, req);
69 }
70 
71 #endif /* __U_F_H__ */
72