/*
 * Copyright (C) 2009 Michal Simek <monstr@monstr.eu>
 * Copyright (C) 2009 PetaLogix
 * Copyright (C) 2007 LynuxWorks, Inc.
 *
 * 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.
 */

#include <linux/errno.h>
#include <linux/linkage.h>
#include <asm/page.h>

/*
 * int __strncpy_user(char *to, char *from, int len);
 *
 * Returns:
 *  -EFAULT  for an exception
 *  len      if we hit the buffer limit
 *  bytes copied
 */

	.text
.globl __strncpy_user;
.type  __strncpy_user, @function
.align 4;
__strncpy_user:

	/*
	 * r5 - to
	 * r6 - from
	 * r7 - len
	 * r3 - temp count
	 * r4 - temp val
	 */
	addik	r3,r7,0		/* temp_count = len */
	beqi	r3,3f
1:
	lbu	r4,r6,r0
	sb	r4,r5,r0

	addik	r3,r3,-1
	beqi	r3,2f		/* break on len */

	addik	r5,r5,1
	bneid	r4,1b
	addik	r6,r6,1		/* delay slot */
	addik	r3,r3,1		/* undo "temp_count--" */
2:
	rsubk	r3,r3,r7	/* temp_count = len - temp_count */
3:
	rtsd	r15,8
	nop
	.size   __strncpy_user, . - __strncpy_user

	.section	.fixup, "ax"
	.align	2
4:
	brid	3b
	addik	r3,r0, -EFAULT

	.section	__ex_table, "a"
	.word	1b,4b

/*
 * int __strnlen_user(char __user *str, int maxlen);
 *
 * Returns:
 *  0 on error
 *  maxlen + 1  if no NUL byte found within maxlen bytes
 *  size of the string (including NUL byte)
 */

	.text
.globl __strnlen_user;
.type  __strnlen_user, @function
.align 4;
__strnlen_user:
	addik	r3,r6,0
	beqi	r3,3f
1:
	lbu	r4,r5,r0
	beqid	r4,2f		/* break on NUL */
	addik	r3,r3,-1	/* delay slot */

	bneid	r3,1b
	addik	r5,r5,1		/* delay slot */

	addik	r3,r3,-1	/* for break on len */
2:
	rsubk	r3,r3,r6
3:
	rtsd	r15,8
	nop
	.size   __strnlen_user, . - __strnlen_user

	.section	.fixup,"ax"
4:
	brid	3b
	addk	r3,r0,r0

	.section	__ex_table,"a"
	.word	1b,4b

/* Loop unrolling for __copy_tofrom_user */
#define COPY(offset)	\
1:	lwi	r4 , r6, 0x0000 + offset;	\
2:	lwi	r19, r6, 0x0004 + offset;	\
3:	lwi	r20, r6, 0x0008 + offset;	\
4:	lwi	r21, r6, 0x000C + offset;	\
5:	lwi	r22, r6, 0x0010 + offset;	\
6:	lwi	r23, r6, 0x0014 + offset;	\
7:	lwi	r24, r6, 0x0018 + offset;	\
8:	lwi	r25, r6, 0x001C + offset;	\
9:	swi	r4 , r5, 0x0000 + offset;	\
10:	swi	r19, r5, 0x0004 + offset;	\
11:	swi	r20, r5, 0x0008 + offset;	\
12:	swi	r21, r5, 0x000C + offset;	\
13:	swi	r22, r5, 0x0010 + offset;	\
14:	swi	r23, r5, 0x0014 + offset;	\
15:	swi	r24, r5, 0x0018 + offset;	\
16:	swi	r25, r5, 0x001C + offset;	\
	.section __ex_table,"a";		\
	.word	1b, 0f;				\
	.word	2b, 0f;				\
	.word	3b, 0f;				\
	.word	4b, 0f;				\
	.word	5b, 0f;				\
	.word	6b, 0f;				\
	.word	7b, 0f;				\
	.word	8b, 0f;				\
	.word	9b, 0f;				\
	.word	10b, 0f;			\
	.word	11b, 0f;			\
	.word	12b, 0f;			\
	.word	13b, 0f;			\
	.word	14b, 0f;			\
	.word	15b, 0f;			\
	.word	16b, 0f;			\
	.text

#define COPY_80(offset)	\
	COPY(0x00 + offset);\
	COPY(0x20 + offset);\
	COPY(0x40 + offset);\
	COPY(0x60 + offset);

/*
 * int __copy_tofrom_user(char *to, char *from, int len)
 * Return:
 *   0 on success
 *   number of not copied bytes on error
 */
	.text
.globl __copy_tofrom_user;
.type  __copy_tofrom_user, @function
.align 4;
__copy_tofrom_user:
	/*
	 * r5 - to
	 * r6 - from
	 * r7, r3 - count
	 * r4 - tempval
	 */
	beqid	r7, 0f /* zero size is not likely */
	or	r3, r5, r6 /* find if is any to/from unaligned */
	or	r3, r3, r7 /* find if count is unaligned */
	andi	r3, r3, 0x3 /* mask last 3 bits */
	bneid	r3, bu1 /* if r3 is not zero then byte copying */
	or	r3, r0, r0

	rsubi	r3, r7, PAGE_SIZE /* detect PAGE_SIZE */
	beqid	r3, page;
	or	r3, r0, r0

w1:	lw	r4, r6, r3 /* at least one 4 byte copy */
w2:	sw	r4, r5, r3
	addik	r7, r7, -4
	bneid	r7, w1
	addik	r3, r3, 4
	addik	r3, r7, 0
	rtsd	r15, 8
	nop

	.section	__ex_table,"a"
	.word	w1, 0f;
	.word	w2, 0f;
	.text

.align 4 /* Alignment is important to keep icache happy */
page:	/* Create room on stack and save registers for storign values */
	addik   r1, r1, -32
	swi	r19, r1, 4
	swi	r20, r1, 8
	swi	r21, r1, 12
	swi	r22, r1, 16
	swi	r23, r1, 20
	swi	r24, r1, 24
	swi	r25, r1, 28
loop:	/* r4, r19, r20, r21, r22, r23, r24, r25 are used for storing values */
	/* Loop unrolling to get performance boost */
	COPY_80(0x000);
	COPY_80(0x080);
	COPY_80(0x100);
	COPY_80(0x180);
	/* copy loop */
	addik	r6, r6, 0x200
	addik	r7, r7, -0x200
	bneid	r7, loop
	addik	r5, r5, 0x200
	/* Restore register content */
	lwi	r19, r1, 4
	lwi	r20, r1, 8
	lwi	r21, r1, 12
	lwi	r22, r1, 16
	lwi	r23, r1, 20
	lwi	r24, r1, 24
	lwi	r25, r1, 28
	addik   r1, r1, 32
	/* return back */
	addik	r3, r7, 0
	rtsd	r15, 8
	nop

.align 4 /* Alignment is important to keep icache happy */
bu1:	lbu	r4,r6,r3
bu2:	sb	r4,r5,r3
	addik	r7,r7,-1
	bneid	r7,bu1
	addik	r3,r3,1		/* delay slot */
0:
	addik	r3,r7,0
	rtsd	r15,8
	nop
	.size   __copy_tofrom_user, . - __copy_tofrom_user

	.section	__ex_table,"a"
	.word	bu1, 0b;
	.word	bu2, 0b;
	.text