xref: /openbmc/linux/drivers/usb/gadget/u_f.h (revision be709d48)
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 
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__ */
71