sh: Optimise memcpy_to/fromio for SH4
Optimise memcpy_to/fromio. This is used extensivly by MTD, so is a
worthwhile performance gain. The main savings come from not repeatedly
calling readl/writel, and doing word instead of byte at a time
transfers. Also using "movca.l" on SH4 gives a small performance win.
Signed-off-by: Stuart Menefy <stuart.menefy@st.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
diff --git a/arch/sh/kernel/io.c b/arch/sh/kernel/io.c
index d0ca968..4770c24 100644
--- a/arch/sh/kernel/io.c
+++ b/arch/sh/kernel/io.c
@@ -1,12 +1,9 @@
/*
- * linux/arch/sh/kernel/io.c
+ * arch/sh/kernel/io.c - Machine independent I/O functions.
*
- * Copyright (C) 2000 Stuart Menefy
+ * Copyright (C) 2000 - 2009 Stuart Menefy
* Copyright (C) 2005 Paul Mundt
*
- * Provide real functions which expand to whatever the header file defined.
- * Also definitions of machine independent IO functions.
- *
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
@@ -18,33 +15,87 @@
/*
* Copy data from IO memory space to "real" memory space.
- * This needs to be optimized.
*/
void memcpy_fromio(void *to, const volatile void __iomem *from, unsigned long count)
{
- unsigned char *p = to;
- while (count) {
- count--;
- *p = readb(from);
- p++;
- from++;
- }
+ /*
+ * Would it be worthwhile doing byte and long transfers first
+ * to try and get aligned?
+ */
+#ifdef CONFIG_CPU_SH4
+ if ((count >= 0x20) &&
+ (((u32)to & 0x1f) == 0) && (((u32)from & 0x3) == 0)) {
+ int tmp2, tmp3, tmp4, tmp5, tmp6;
+
+ __asm__ __volatile__(
+ "1: \n\t"
+ "mov.l @%7+, r0 \n\t"
+ "mov.l @%7+, %2 \n\t"
+ "movca.l r0, @%0 \n\t"
+ "mov.l @%7+, %3 \n\t"
+ "mov.l @%7+, %4 \n\t"
+ "mov.l @%7+, %5 \n\t"
+ "mov.l @%7+, %6 \n\t"
+ "mov.l @%7+, r7 \n\t"
+ "mov.l @%7+, r0 \n\t"
+ "mov.l %2, @(0x04,%0) \n\t"
+ "mov #0x20, %2 \n\t"
+ "mov.l %3, @(0x08,%0) \n\t"
+ "sub %2, %1 \n\t"
+ "mov.l %4, @(0x0c,%0) \n\t"
+ "cmp/hi %1, %2 ! T if 32 > count \n\t"
+ "mov.l %5, @(0x10,%0) \n\t"
+ "mov.l %6, @(0x14,%0) \n\t"
+ "mov.l r7, @(0x18,%0) \n\t"
+ "mov.l r0, @(0x1c,%0) \n\t"
+ "bf.s 1b \n\t"
+ " add #0x20, %0 \n\t"
+ : "=&r" (to), "=&r" (count),
+ "=&r" (tmp2), "=&r" (tmp3), "=&r" (tmp4),
+ "=&r" (tmp5), "=&r" (tmp6), "=&r" (from)
+ : "7"(from), "0" (to), "1" (count)
+ : "r0", "r7", "t", "memory");
+ }
+#endif
+
+ if ((((u32)to | (u32)from) & 0x3) == 0) {
+ for (; count > 3; count -= 4) {
+ *(u32 *)to = *(volatile u32 *)from;
+ to += 4;
+ from += 4;
+ }
+ }
+
+ for (; count > 0; count--) {
+ *(u8 *)to = *(volatile u8 *)from;
+ to++;
+ from++;
+ }
+
+ mb();
}
EXPORT_SYMBOL(memcpy_fromio);
/*
* Copy data from "real" memory space to IO memory space.
- * This needs to be optimized.
*/
void memcpy_toio(volatile void __iomem *to, const void *from, unsigned long count)
{
- const unsigned char *p = from;
- while (count) {
- count--;
- writeb(*p, to);
- p++;
- to++;
- }
+ if ((((u32)to | (u32)from) & 0x3) == 0) {
+ for ( ; count > 3; count -= 4) {
+ *(volatile u32 *)to = *(u32 *)from;
+ to += 4;
+ from += 4;
+ }
+ }
+
+ for (; count > 0; count--) {
+ *(volatile u8 *)to = *(u8 *)from;
+ to++;
+ from++;
+ }
+
+ mb();
}
EXPORT_SYMBOL(memcpy_toio);