xref: /openbmc/linux/arch/x86/lib/iomem.c (revision 176f011b)
1 #include <linux/string.h>
2 #include <linux/module.h>
3 #include <linux/io.h>
4 
5 /* Originally from i386/string.h */
6 static __always_inline void __iomem_memcpy(void *to, const void *from, size_t n)
7 {
8 	unsigned long d0, d1, d2;
9 	asm volatile("rep ; movsl\n\t"
10 		     "testb $2,%b4\n\t"
11 		     "je 1f\n\t"
12 		     "movsw\n"
13 		     "1:\ttestb $1,%b4\n\t"
14 		     "je 2f\n\t"
15 		     "movsb\n"
16 		     "2:"
17 		     : "=&c" (d0), "=&D" (d1), "=&S" (d2)
18 		     : "0" (n / 4), "q" (n), "1" ((long)to), "2" ((long)from)
19 		     : "memory");
20 }
21 
22 void memcpy_fromio(void *to, const volatile void __iomem *from, size_t n)
23 {
24 	__iomem_memcpy(to, (const void *)from, n);
25 }
26 EXPORT_SYMBOL(memcpy_fromio);
27 
28 void memcpy_toio(volatile void __iomem *to, const void *from, size_t n)
29 {
30 	__iomem_memcpy((void *)to, (const void *) from, n);
31 }
32 EXPORT_SYMBOL(memcpy_toio);
33 
34 void memset_io(volatile void __iomem *a, int b, size_t c)
35 {
36 	/*
37 	 * TODO: memset can mangle the IO patterns quite a bit.
38 	 * perhaps it would be better to use a dumb one:
39 	 */
40 	memset((void *)a, b, c);
41 }
42 EXPORT_SYMBOL(memset_io);
43