linux-stable/arch/powerpc/kernel/io.c
Albrecht Dreß a22c65f81a powerpc: tiny memcpy_(to|from)io optimisation
This trivial patch changes memcpy_(to|from)io as to transfer as many
32-bit words as possible in 32-bit accesses (in the current solution,
the last 32-bit word was transferred as 4 byte accesses).

Signed-off-by: Albrecht Dreß <albrecht.dress@arcor.de>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
2009-11-04 16:43:12 -07:00

207 lines
4.2 KiB
C

/*
* I/O string operations
* Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
* Copyright (C) 2006 IBM Corporation
*
* Largely rewritten by Cort Dougan (cort@cs.nmt.edu)
* and Paul Mackerras.
*
* Adapted for iSeries by Mike Corrigan (mikejc@us.ibm.com)
* PPC64 updates by Dave Engebretsen (engebret@us.ibm.com)
*
* Rewritten in C by Stephen Rothwell.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/compiler.h>
#include <linux/module.h>
#include <asm/io.h>
#include <asm/firmware.h>
#include <asm/bug.h>
void _insb(const volatile u8 __iomem *port, void *buf, long count)
{
u8 *tbuf = buf;
u8 tmp;
if (unlikely(count <= 0))
return;
asm volatile("sync");
do {
tmp = *port;
eieio();
*tbuf++ = tmp;
} while (--count != 0);
asm volatile("twi 0,%0,0; isync" : : "r" (tmp));
}
EXPORT_SYMBOL(_insb);
void _outsb(volatile u8 __iomem *port, const void *buf, long count)
{
const u8 *tbuf = buf;
if (unlikely(count <= 0))
return;
asm volatile("sync");
do {
*port = *tbuf++;
} while (--count != 0);
asm volatile("sync");
}
EXPORT_SYMBOL(_outsb);
void _insw_ns(const volatile u16 __iomem *port, void *buf, long count)
{
u16 *tbuf = buf;
u16 tmp;
if (unlikely(count <= 0))
return;
asm volatile("sync");
do {
tmp = *port;
eieio();
*tbuf++ = tmp;
} while (--count != 0);
asm volatile("twi 0,%0,0; isync" : : "r" (tmp));
}
EXPORT_SYMBOL(_insw_ns);
void _outsw_ns(volatile u16 __iomem *port, const void *buf, long count)
{
const u16 *tbuf = buf;
if (unlikely(count <= 0))
return;
asm volatile("sync");
do {
*port = *tbuf++;
} while (--count != 0);
asm volatile("sync");
}
EXPORT_SYMBOL(_outsw_ns);
void _insl_ns(const volatile u32 __iomem *port, void *buf, long count)
{
u32 *tbuf = buf;
u32 tmp;
if (unlikely(count <= 0))
return;
asm volatile("sync");
do {
tmp = *port;
eieio();
*tbuf++ = tmp;
} while (--count != 0);
asm volatile("twi 0,%0,0; isync" : : "r" (tmp));
}
EXPORT_SYMBOL(_insl_ns);
void _outsl_ns(volatile u32 __iomem *port, const void *buf, long count)
{
const u32 *tbuf = buf;
if (unlikely(count <= 0))
return;
asm volatile("sync");
do {
*port = *tbuf++;
} while (--count != 0);
asm volatile("sync");
}
EXPORT_SYMBOL(_outsl_ns);
#define IO_CHECK_ALIGN(v,a) ((((unsigned long)(v)) & ((a) - 1)) == 0)
notrace void
_memset_io(volatile void __iomem *addr, int c, unsigned long n)
{
void *p = (void __force *)addr;
u32 lc = c;
lc |= lc << 8;
lc |= lc << 16;
__asm__ __volatile__ ("sync" : : : "memory");
while(n && !IO_CHECK_ALIGN(p, 4)) {
*((volatile u8 *)p) = c;
p++;
n--;
}
while(n >= 4) {
*((volatile u32 *)p) = lc;
p += 4;
n -= 4;
}
while(n) {
*((volatile u8 *)p) = c;
p++;
n--;
}
__asm__ __volatile__ ("sync" : : : "memory");
}
EXPORT_SYMBOL(_memset_io);
void _memcpy_fromio(void *dest, const volatile void __iomem *src,
unsigned long n)
{
void *vsrc = (void __force *) src;
__asm__ __volatile__ ("sync" : : : "memory");
while(n && (!IO_CHECK_ALIGN(vsrc, 4) || !IO_CHECK_ALIGN(dest, 4))) {
*((u8 *)dest) = *((volatile u8 *)vsrc);
eieio();
vsrc++;
dest++;
n--;
}
while(n >= 4) {
*((u32 *)dest) = *((volatile u32 *)vsrc);
eieio();
vsrc += 4;
dest += 4;
n -= 4;
}
while(n) {
*((u8 *)dest) = *((volatile u8 *)vsrc);
eieio();
vsrc++;
dest++;
n--;
}
__asm__ __volatile__ ("sync" : : : "memory");
}
EXPORT_SYMBOL(_memcpy_fromio);
void _memcpy_toio(volatile void __iomem *dest, const void *src, unsigned long n)
{
void *vdest = (void __force *) dest;
__asm__ __volatile__ ("sync" : : : "memory");
while(n && (!IO_CHECK_ALIGN(vdest, 4) || !IO_CHECK_ALIGN(src, 4))) {
*((volatile u8 *)vdest) = *((u8 *)src);
src++;
vdest++;
n--;
}
while(n >= 4) {
*((volatile u32 *)vdest) = *((volatile u32 *)src);
src += 4;
vdest += 4;
n-=4;
}
while(n) {
*((volatile u8 *)vdest) = *((u8 *)src);
src++;
vdest++;
n--;
}
__asm__ __volatile__ ("sync" : : : "memory");
}
EXPORT_SYMBOL(_memcpy_toio);