1 /*
2  * Copyright (C) 2019 The Android Open Source Project
3  *
4  * Permission is hereby granted, free of charge, to any person
5  * obtaining a copy of this software and associated documentation
6  * files (the "Software"), to deal in the Software without
7  * restriction, including without limitation the rights to use, copy,
8  * modify, merge, publish, distribute, sublicense, and/or sell copies
9  * of the Software, and to permit persons to whom the Software is
10  * furnished to do so, subject to the following conditions:
11  *
12  * The above copyright notice and this permission notice shall be
13  * included in all copies or substantial portions of the Software.
14  *
15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
16  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
17  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
18  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
19  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
20  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
21  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
22  * SOFTWARE.
23  */
24 
25 #pragma once
26 
27 /*
28  * Defines primitives for accessing memory mapped devices.
29  * As both VirtIO and PCI use little endian, and we support only
30  * AArch64, we do not perform endianness conversions.
31  */
32 
33 #include <stdint.h>
34 
35 #define rmb() __asm__ __volatile__("dmb ld" : : : "memory")
36 #define wmb() __asm__ __volatile__("dmb st" : : : "memory")
37 
38 #define u(width) uint##width##_t
39 
40 #define build_io(width, prefix, suffix)                                      \
41     static inline u(width) io_read_##width(const volatile u(width) * addr) { \
42         u(width) out;                                                        \
43         __asm__ __volatile__("ldr" suffix " %" prefix "0, [%1]"              \
44                              : "=r"(out)                                     \
45                              : "r"(addr));                                   \
46         rmb();                                                               \
47         return out;                                                          \
48     }                                                                        \
49     static inline void io_write_##width(volatile u(width) * addr,            \
50                                         u(width) val) {                      \
51         wmb();                                                               \
52         __asm__ __volatile__("str" suffix " %" prefix "0, [%1]"              \
53                              :                                               \
54                              : "rZ"(val), "r"(addr)                          \
55                              : "memory");                                    \
56     }
57 
58 build_io(8, "w", "b");
59 build_io(16, "w", "h");
60 build_io(32, "w", "");
61 build_io(64, "x", "");
62 
63 #undef u
64 #undef build_io
65