xref: /openbmc/linux/arch/arm64/kernel/io.c (revision 6d99a79c)
1 /*
2  * Based on arch/arm/kernel/io.c
3  *
4  * Copyright (C) 2012 ARM Ltd.
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License version 2 as
8  * published by the Free Software Foundation.
9  *
10  * This program is distributed in the hope that it will be useful,
11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13  * GNU General Public License for more details.
14  *
15  * You should have received a copy of the GNU General Public License
16  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
17  */
18 
19 #include <linux/export.h>
20 #include <linux/types.h>
21 #include <linux/io.h>
22 
23 /*
24  * Copy data from IO memory space to "real" memory space.
25  */
26 void __memcpy_fromio(void *to, const volatile void __iomem *from, size_t count)
27 {
28 	while (count && !IS_ALIGNED((unsigned long)from, 8)) {
29 		*(u8 *)to = __raw_readb(from);
30 		from++;
31 		to++;
32 		count--;
33 	}
34 
35 	while (count >= 8) {
36 		*(u64 *)to = __raw_readq(from);
37 		from += 8;
38 		to += 8;
39 		count -= 8;
40 	}
41 
42 	while (count) {
43 		*(u8 *)to = __raw_readb(from);
44 		from++;
45 		to++;
46 		count--;
47 	}
48 }
49 EXPORT_SYMBOL(__memcpy_fromio);
50 
51 /*
52  * Copy data from "real" memory space to IO memory space.
53  */
54 void __memcpy_toio(volatile void __iomem *to, const void *from, size_t count)
55 {
56 	while (count && !IS_ALIGNED((unsigned long)to, 8)) {
57 		__raw_writeb(*(u8 *)from, to);
58 		from++;
59 		to++;
60 		count--;
61 	}
62 
63 	while (count >= 8) {
64 		__raw_writeq(*(u64 *)from, to);
65 		from += 8;
66 		to += 8;
67 		count -= 8;
68 	}
69 
70 	while (count) {
71 		__raw_writeb(*(u8 *)from, to);
72 		from++;
73 		to++;
74 		count--;
75 	}
76 }
77 EXPORT_SYMBOL(__memcpy_toio);
78 
79 /*
80  * "memset" on IO memory space.
81  */
82 void __memset_io(volatile void __iomem *dst, int c, size_t count)
83 {
84 	u64 qc = (u8)c;
85 
86 	qc |= qc << 8;
87 	qc |= qc << 16;
88 	qc |= qc << 32;
89 
90 	while (count && !IS_ALIGNED((unsigned long)dst, 8)) {
91 		__raw_writeb(c, dst);
92 		dst++;
93 		count--;
94 	}
95 
96 	while (count >= 8) {
97 		__raw_writeq(qc, dst);
98 		dst += 8;
99 		count -= 8;
100 	}
101 
102 	while (count) {
103 		__raw_writeb(c, dst);
104 		dst++;
105 		count--;
106 	}
107 }
108 EXPORT_SYMBOL(__memset_io);
109