From: H. Peter Anvin <[email protected]>
Optimal memcpy for moves to/from IO space. Does as few moves as
possible while keeping transfers optimally aligned.
Signed-off-by: Chuck Ebbert <[email protected]>
---
Andrew, remove i386-memcpy-use-as-few-moves-as.patch from -mm
and replace it with this, please.
arch/i386/lib/memcpy.c | 57 +++++++++++++++++++++++++++++++++++++++++++++++++
include/asm-i386/io.h | 11 ++-------
2 files changed, 60 insertions(+), 8 deletions(-)
--- 2.6.17-rc5-32.orig/arch/i386/lib/memcpy.c
+++ 2.6.17-rc5-32/arch/i386/lib/memcpy.c
@@ -42,3 +42,60 @@ void *memmove(void *dest, const void *sr
return dest;
}
EXPORT_SYMBOL(memmove);
+
+/*
+ * The most general form of memory copy to/from I/O space, used for
+ * devices which can handle arbitrary transactions with appropriate
+ * handling of byte enables. The goal is to produce the minimum
+ * number of naturally aligned transactions on the bus.
+ */
+
+#define build_memcpy_io(dst, src, count, align_reg) \
+({ \
+unsigned long d0, d1, d2, d3; \
+asm volatile( \
+ "jecxz 1f\n\t" \
+ \
+ "testl $1, " align_reg "\n\t" \
+ "jz 2f\n\t" \
+ "movsb\n\t" \
+ "decl %2\n" \
+"2:\n\t" \
+ "cmpl $2, %2\n\t" \
+ "jb 3f\n\t" \
+ "testl $2, " align_reg "\n\t" \
+ "jz 4f\n\t" \
+ "movsw\n\t" \
+ "decl %2\n\t" \
+ "decl %2\n" \
+"4:\n\t" \
+ "movl %2, %3\n\t" \
+ "shrl $2, %2\n\t" \
+ "jz 5f\n\t" \
+ "rep ; movsl\n" \
+"5:\n\t" \
+ "movl %3, %2\n\t" \
+ "testb $2, %b2\n\t" \
+ "jz 3f\n\t" \
+ "movsw\n" \
+"3:\n\t" \
+ "testb $1, %b2\n\t" \
+ "jz 1f\n\t" \
+ "movsb\n" \
+"1:" \
+ : "=&D" (d0), "=&S" (d1), "=&c" (d2), "=&g" (d3)\
+ : "0" (dst), "1" (src), "2" (count) \
+ : "memory"); \
+})
+
+void memcpy_fromio(void *dst, const volatile void __iomem *src, int count)
+{
+ build_memcpy_io(dst, src, count, "%%esi");
+}
+EXPORT_SYMBOL(memcpy_fromio)
+
+void memcpy_toio(volatile void __iomem *dst, const void *src, int count)
+{
+ build_memcpy_io(dst, src, count, "%%edi");
+}
+EXPORT_SYMBOL(memcpy_toio)
--- 2.6.17-rc5-32.orig/include/asm-i386/io.h
+++ 2.6.17-rc5-32/include/asm-i386/io.h
@@ -200,14 +200,9 @@ static inline void memset_io(volatile vo
{
memset((void __force *) addr, val, count);
}
-static inline void memcpy_fromio(void *dst, const volatile void __iomem *src, int count)
-{
- __memcpy(dst, (void __force *) src, count);
-}
-static inline void memcpy_toio(volatile void __iomem *dst, const void *src, int count)
-{
- __memcpy((void __force *) dst, src, count);
-}
+
+extern void memcpy_fromio(void *dst, const volatile void __iomem *src, int count);
+extern void memcpy_toio(volatile void __iomem *dst, const void *src, int count);
/*
* ISA space is 'always mapped' on a typical x86 system, no need to
--
Chuck
-
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