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Commit 5e9377ec authored by Stuart Menefy's avatar Stuart Menefy Committed by Paul Mundt
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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: default avatarStuart Menefy <stuart.menefy@st.com>
Signed-off-by: default avatarPaul Mundt <lethal@linux-sh.org>
parent 8af57f8b

arch/sh/kernel/io.c

+72 −21
Original line number Original line Diff line number Diff line 
/*

/*

 * 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

 * 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

 * 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

 * License.  See the file "COPYING" in the main directory of this archive

 * for more details.

 * for more details.
@@ -18,33 +15,87 @@ 




/*

/*

 * Copy data from IO memory space to "real" memory space.

 * 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)

void memcpy_fromio(void *to, const volatile void __iomem *from, unsigned long count)

{

{

	unsigned char *p = to;

	/*

        while (count) {

	 * Would it be worthwhile doing byte and long transfers first

                count--;

	 * to try and get aligned?

                *p = readb(from);

	 */

                p++;

#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++;

		from++;

	}

	}



	mb();

}

}

EXPORT_SYMBOL(memcpy_fromio);

EXPORT_SYMBOL(memcpy_fromio);





/*

/*

 * Copy data from "real" memory space to IO memory space.

 * 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)

void memcpy_toio(volatile void __iomem *to, const void *from, unsigned long count)

{

{

	const unsigned char *p = from;

	if ((((u32)to | (u32)from) & 0x3) == 0) {

        while (count) {

		for ( ; count > 3; count -= 4) {

                count--;

			*(volatile u32 *)to = *(u32 *)from;

                writeb(*p, to);

			to += 4;

                p++;

			from += 4;

		}

	}



	for (; count > 0; count--) {

		*(volatile u8 *)to = *(u8 *)from;

		to++;

		to++;

		from++;

	}

	}



	mb();

}

}

EXPORT_SYMBOL(memcpy_toio);

EXPORT_SYMBOL(memcpy_toio);