1#include <linux/string.h>
 2#include <linux/module.h>
 3#include <linux/io.h>
 4
 5#define movs(type,to,from) \
 6	asm volatile("movs" type:"=&D" (to), "=&S" (from):"0" (to), "1" (from):"memory")
 7
 8/* Originally from i386/string.h */
 9static __always_inline void rep_movs(void *to, const void *from, size_t n)
10{
11	unsigned long d0, d1, d2;
12	asm volatile("rep ; movsl\n\t"
13		     "testb $2,%b4\n\t"
14		     "je 1f\n\t"
15		     "movsw\n"
16		     "1:\ttestb $1,%b4\n\t"
17		     "je 2f\n\t"
18		     "movsb\n"
19		     "2:"
20		     : "=&c" (d0), "=&D" (d1), "=&S" (d2)
21		     : "0" (n / 4), "q" (n), "1" ((long)to), "2" ((long)from)
22		     : "memory");
23}
24
25void memcpy_fromio(void *to, const volatile void __iomem *from, size_t n)
26{
27	if (unlikely(!n))
28		return;
29
30	/* Align any unaligned source IO */
31	if (unlikely(1 & (unsigned long)from)) {
32		movs("b", to, from);
33		n--;
34	}
35	if (n > 1 && unlikely(2 & (unsigned long)from)) {
36		movs("w", to, from);
37		n-=2;
38	}
39	rep_movs(to, (const void *)from, n);
40}
41EXPORT_SYMBOL(memcpy_fromio);
42
43void memcpy_toio(volatile void __iomem *to, const void *from, size_t n)
44{
45	if (unlikely(!n))
46		return;
47
48	/* Align any unaligned destination IO */
49	if (unlikely(1 & (unsigned long)to)) {
50		movs("b", to, from);
51		n--;
52	}
53	if (n > 1 && unlikely(2 & (unsigned long)to)) {
54		movs("w", to, from);
55		n-=2;
56	}
57	rep_movs((void *)to, (const void *) from, n);
58}
59EXPORT_SYMBOL(memcpy_toio);
60
61void memset_io(volatile void __iomem *a, int b, size_t c)
62{
63	/*
64	 * TODO: memset can mangle the IO patterns quite a bit.
65	 * perhaps it would be better to use a dumb one:
66	 */
67	memset((void *)a, b, c);
68}
69EXPORT_SYMBOL(memset_io);