arch/x86/lib/iomem.c

   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);