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Subject[PATCH] ppc64: fix memcpy_to/from_io
From
Date
Hi !

The ppc64 implementation of memcpy_to/from_io was bogus (used memcpy
which uses cache hints and thus is broken on non cacheable IO space).

This re-implements them with some simple/gross C code doing 32 bits
accesses when aligned and bytes accesses when not.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

===== include/asm-ppc64/eeh.h 1.12 vs ? (writable without lock!) =====
--- 1.12/include/asm-ppc64/eeh.h 2004-07-02 15:23:45 +10:00
+++ ?/include/asm-ppc64/eeh.h 2004-07-30 14:19:48 +10:00
@@ -180,26 +180,95 @@
out_be64(vaddr, val);
}

+#define EEH_CHECK_ALIGN(v,a) \
+ ((((unsigned long)(v)) & ((a) - 1)) == 0)
+
static inline void eeh_memset_io(void *addr, int c, unsigned long n) {
void *vaddr = (void *)IO_TOKEN_TO_ADDR(addr);
- memset(vaddr, c, n);
+ u32 lc = c;
+ lc |= lc << 8;
+ lc |= lc << 16;
+
+ while(n && !EEH_CHECK_ALIGN(vaddr, 4)) {
+ *((volatile u8 *)vaddr) = c;
+ vaddr = (void *)((unsigned long)vaddr + 1);
+ n--;
+ }
+ while(n >= 4) {
+ *((volatile u32 *)vaddr) = lc;
+ vaddr = (void *)((unsigned long)vaddr + 4);
+ n -= 4;
+ }
+ while(n) {
+ *((volatile u8 *)vaddr) = c;
+ vaddr = (void *)((unsigned long)vaddr + 1);
+ n--;
+ }
+ __asm__ __volatile__ ("sync" : : : "memory");
}
static inline void eeh_memcpy_fromio(void *dest, void *src, unsigned long n) {
void *vsrc = (void *)IO_TOKEN_TO_ADDR(src);
- memcpy(dest, vsrc, n);
+ void *vsrcsave = vsrc, *destsave = dest, *srcsave = src;
+ unsigned long nsave = n;
+
+ while(n && (!EEH_CHECK_ALIGN(vsrc, 4) || !EEH_CHECK_ALIGN(dest, 4))) {
+ *((u8 *)dest) = *((volatile u8 *)vsrc);
+ __asm__ __volatile__ ("eieio" : : : "memory");
+ vsrc = (void *)((unsigned long)vsrc + 1);
+ dest = (void *)((unsigned long)dest + 1);
+ n--;
+ }
+ while(n > 4) {
+ *((u32 *)dest) = *((volatile u32 *)vsrc);
+ __asm__ __volatile__ ("eieio" : : : "memory");
+ vsrc = (void *)((unsigned long)vsrc + 4);
+ dest = (void *)((unsigned long)dest + 4);
+ n -= 4;
+ }
+ while(n) {
+ *((u8 *)dest) = *((volatile u8 *)vsrc);
+ __asm__ __volatile__ ("eieio" : : : "memory");
+ vsrc = (void *)((unsigned long)vsrc + 1);
+ dest = (void *)((unsigned long)dest + 1);
+ n--;
+ }
+ __asm__ __volatile__ ("sync" : : : "memory");
+
/* Look for ffff's here at dest[n]. Assume that at least 4 bytes
* were copied. Check all four bytes.
*/
- if ((n >= 4) &&
- (EEH_POSSIBLE_ERROR(src, vsrc, (*((u32 *) dest+n-4)), u32))) {
- eeh_check_failure(src, (*((u32 *) dest+n-4)));
+ if ((nsave >= 4) &&
+ (EEH_POSSIBLE_ERROR(srcsave, vsrcsave, (*((u32 *) destsave+nsave-4)),
+ u32))) {
+ eeh_check_failure(srcsave, (*((u32 *) destsave+nsave-4)));
}
}

static inline void eeh_memcpy_toio(void *dest, void *src, unsigned long n) {
void *vdest = (void *)IO_TOKEN_TO_ADDR(dest);
- memcpy(vdest, src, n);
+
+ while(n && (!EEH_CHECK_ALIGN(vdest, 4) || !EEH_CHECK_ALIGN(src, 4))) {
+ *((volatile u8 *)vdest) = *((u8 *)src);
+ src = (void *)((unsigned long)src + 1);
+ vdest = (void *)((unsigned long)vdest + 1);
+ n--;
+ }
+ while(n > 4) {
+ *((volatile u32 *)vdest) = *((volatile u32 *)src);
+ src = (void *)((unsigned long)src + 4);
+ vdest = (void *)((unsigned long)vdest + 4);
+ n-=4;
+ }
+ while(n) {
+ *((volatile u8 *)vdest) = *((u8 *)src);
+ src = (void *)((unsigned long)src + 1);
+ vdest = (void *)((unsigned long)vdest + 1);
+ n--;
+ }
+ __asm__ __volatile__ ("sync" : : : "memory");
}
+
+#undef EEH_CHECK_ALIGN

#define MAX_ISA_PORT 0x10000
extern unsigned long io_page_mask;

-
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