/*
 *  linux/arch/arm/mm/arm925.S: MMU functions for ARM925
 *
 *  Copyright (C) 1999,2000 ARM Limited
 *  Copyright (C) 2000 Deep Blue Solutions Ltd.
 *  Copyright (C) 2002 RidgeRun, Inc.
 *  Copyright (C) 2002-2003 MontaVista Software, Inc.
 *
 *  Update for Linux-2.6 and cache flush improvements
 *  Copyright (C) 2004 Nokia Corporation by Tony Lindgren <tony@atomide.com>
 *
 * 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.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 *
 * These are the low level assembler for performing cache and TLB
 * functions on the arm925.
 *
 *  CONFIG_CPU_ARM925_CPU_IDLE -> nohlt
 *
 * Some additional notes based on deciphering the TI TRM on OMAP-5910:
 *
 * NOTE1: The TI925T Configuration Register bit "D-cache clean and flush
 *	  entry mode" must be 0 to flush the entries in both segments
 *	  at once. This is the default value. See TRM 2-20 and 2-24 for
 *	  more information.
 *
 * NOTE2: Default is the "D-cache clean and flush entry mode". It looks
 *	  like the "Transparent mode" must be on for partial cache flushes
 *	  to work in this mode. This mode only works with 16-bit external
 *	  memory. See TRM 2-24 for more information.
 *
 * NOTE3: Write-back cache flushing seems to be flakey with devices using
 *        direct memory access, such as USB OHCI. The workaround is to use
 *        write-through cache with CONFIG_CPU_DCACHE_WRITETHROUGH (this is
 *        the default for OMAP-1510).
 */

#include <linux/linkage.h>
#include <linux/config.h>
#include <linux/init.h>
#include <asm/assembler.h>
#include <asm/pgtable.h>
#include <asm/procinfo.h>
#include <asm/hardware.h>
#include <asm/page.h>
#include <asm/ptrace.h>
#include "proc-macros.S"

/*
 * The size of one data cache line.
 */
#define CACHE_DLINESIZE	16

/*
 * The number of data cache segments.
 */
#define CACHE_DSEGMENTS	2

/*
 * The number of lines in a cache segment.
 */
#define CACHE_DENTRIES	256

/*
 * This is the size at which it becomes more efficient to
 * clean the whole cache, rather than using the individual
 * cache line maintainence instructions.
 */
#define CACHE_DLIMIT	8192

	.text
/*
 * cpu_arm925_proc_init()
 */
ENTRY(cpu_arm925_proc_init)
	mov	pc, lr

/*
 * cpu_arm925_proc_fin()
 */
ENTRY(cpu_arm925_proc_fin)
	stmfd	sp!, {lr}
	mov	ip, #PSR_F_BIT | PSR_I_BIT | SVC_MODE
	msr	cpsr_c, ip
	bl	arm925_flush_kern_cache_all
	mrc	p15, 0, r0, c1, c0, 0		@ ctrl register
	bic	r0, r0, #0x1000			@ ...i............
	bic	r0, r0, #0x000e			@ ............wca.
	mcr	p15, 0, r0, c1, c0, 0		@ disable caches
	ldmfd	sp!, {pc}

/*
 * cpu_arm925_reset(loc)
 *
 * Perform a soft reset of the system.  Put the CPU into the
 * same state as it would be if it had been reset, and branch
 * to what would be the reset vector.
 *
 * loc: location to jump to for soft reset
 */
	.align	5
ENTRY(cpu_arm925_reset)
	/* Send software reset to MPU and DSP */
	mov	ip, #0xff000000
	orr	ip, ip, #0x00fe0000
	orr	ip, ip, #0x0000ce00
	mov	r4, #1
	strh	r4, [ip, #0x10]

	mov	ip, #0
	mcr	p15, 0, ip, c7, c7, 0		@ invalidate I,D caches
	mcr	p15, 0, ip, c7, c10, 4		@ drain WB
	mcr	p15, 0, ip, c8, c7, 0		@ invalidate I & D TLBs
	mrc	p15, 0, ip, c1, c0, 0		@ ctrl register
	bic	ip, ip, #0x000f			@ ............wcam
	bic	ip, ip, #0x1100			@ ...i...s........
	mcr	p15, 0, ip, c1, c0, 0		@ ctrl register
	mov	pc, r0

/*
 * cpu_arm925_do_idle()
 *
 * Called with IRQs disabled
 */
	.align	10
ENTRY(cpu_arm925_do_idle)
	mov	r0, #0
	mrc	p15, 0, r1, c1, c0, 0		@ Read control register
	mcr	p15, 0, r0, c7, c10, 4		@ Drain write buffer
	bic	r2, r1, #1 << 12
	mcr	p15, 0, r2, c1, c0, 0		@ Disable I cache
	mcr	p15, 0, r0, c7, c0, 4		@ Wait for interrupt
	mcr	p15, 0, r1, c1, c0, 0		@ Restore ICache enable
	mov	pc, lr

/*
 *	flush_user_cache_all()
 *
 *	Clean and invalidate all cache entries in a particular
 *	address space.
 */
ENTRY(arm925_flush_user_cache_all)
	/* FALLTHROUGH */

/*
 *	flush_kern_cache_all()
 *
 *	Clean and invalidate the entire cache.
 */
ENTRY(arm925_flush_kern_cache_all)
	mov	r2, #VM_EXEC
	mov	ip, #0
__flush_whole_cache:
#ifdef CONFIG_CPU_DCACHE_WRITETHROUGH
	mcr	p15, 0, ip, c7, c6, 0		@ invalidate D cache
#else
	/* Flush entries in both segments at once, see NOTE1 above */
	mov	r3, #(CACHE_DENTRIES - 1) << 4	@ 256 entries in segment
2:	mcr	p15, 0, r3, c7, c14, 2		@ clean+invalidate D index
	subs	r3, r3, #1 << 4
	bcs	2b				@ entries 255 to 0
#endif
	tst	r2, #VM_EXEC
	mcrne	p15, 0, ip, c7, c5, 0		@ invalidate I cache
	mcrne	p15, 0, ip, c7, c10, 4		@ drain WB
	mov	pc, lr

/*
 *	flush_user_cache_range(start, end, flags)
 *
 *	Clean and invalidate a range of cache entries in the
 *	specified address range.
 *
 *	- start	- start address (inclusive)
 *	- end	- end address (exclusive)
 *	- flags	- vm_flags describing address space
 */
ENTRY(arm925_flush_user_cache_range)
	mov	ip, #0
	sub	r3, r1, r0			@ calculate total size
	cmp	r3, #CACHE_DLIMIT
	bgt	__flush_whole_cache
1:	tst	r2, #VM_EXEC
#ifdef CONFIG_CPU_DCACHE_WRITETHROUGH
	mcr	p15, 0, r0, c7, c6, 1		@ invalidate D entry
	mcrne	p15, 0, r0, c7, c5, 1		@ invalidate I entry
	add	r0, r0, #CACHE_DLINESIZE
	mcr	p15, 0, r0, c7, c6, 1		@ invalidate D entry
	mcrne	p15, 0, r0, c7, c5, 1		@ invalidate I entry
	add	r0, r0, #CACHE_DLINESIZE
#else
	mcr	p15, 0, r0, c7, c14, 1		@ clean and invalidate D entry
	mcrne	p15, 0, r0, c7, c5, 1		@ invalidate I entry
	add	r0, r0, #CACHE_DLINESIZE
	mcr	p15, 0, r0, c7, c14, 1		@ clean and invalidate D entry
	mcrne	p15, 0, r0, c7, c5, 1		@ invalidate I entry
	add	r0, r0, #CACHE_DLINESIZE
#endif
	cmp	r0, r1
	blo	1b
	tst	r2, #VM_EXEC
	mcrne	p15, 0, ip, c7, c10, 4		@ drain WB
	mov	pc, lr

/*
 *	coherent_kern_range(start, end)
 *
 *	Ensure coherency between the Icache and the Dcache in the
 *	region described by start, end.  If you have non-snooping
 *	Harvard caches, you need to implement this function.
 *
 *	- start	- virtual start address
 *	- end	- virtual end address
 */
ENTRY(arm925_coherent_kern_range)
	/* FALLTHROUGH */

/*
 *	coherent_user_range(start, end)
 *
 *	Ensure coherency between the Icache and the Dcache in the
 *	region described by start, end.  If you have non-snooping
 *	Harvard caches, you need to implement this function.
 *
 *	- start	- virtual start address
 *	- end	- virtual end address
 */
ENTRY(arm925_coherent_user_range)
	bic	r0, r0, #CACHE_DLINESIZE - 1
1:	mcr	p15, 0, r0, c7, c10, 1		@ clean D entry
	mcr	p15, 0, r0, c7, c5, 1		@ invalidate I entry
	add	r0, r0, #CACHE_DLINESIZE
	cmp	r0, r1
	blo	1b
	mcr	p15, 0, r0, c7, c10, 4		@ drain WB
	mov	pc, lr

/*
 *	flush_kern_dcache_page(void *page)
 *
 *	Ensure no D cache aliasing occurs, either with itself or
 *	the I cache
 *
 *	- addr	- page aligned address
 */
ENTRY(arm925_flush_kern_dcache_page)
	add	r1, r0, #PAGE_SZ
1:	mcr	p15, 0, r0, c7, c14, 1		@ clean+invalidate D entry
	add	r0, r0, #CACHE_DLINESIZE
	cmp	r0, r1
	blo	1b
	mov	r0, #0
	mcr	p15, 0, r0, c7, c5, 0		@ invalidate I cache
	mcr	p15, 0, r0, c7, c10, 4		@ drain WB
	mov	pc, lr

/*
 *	dma_inv_range(start, end)
 *
 *	Invalidate (discard) the specified virtual address range.
 *	May not write back any entries.  If 'start' or 'end'
 *	are not cache line aligned, those lines must be written
 *	back.
 *
 *	- start	- virtual start address
 *	- end	- virtual end address
 *
 * (same as v4wb)
 */
ENTRY(arm925_dma_inv_range)
#ifndef CONFIG_CPU_DCACHE_WRITETHROUGH
	tst	r0, #CACHE_DLINESIZE - 1
	mcrne	p15, 0, r0, c7, c10, 1		@ clean D entry
	tst	r1, #CACHE_DLINESIZE - 1
	mcrne	p15, 0, r1, c7, c10, 1		@ clean D entry
#endif
	bic	r0, r0, #CACHE_DLINESIZE - 1
1:	mcr	p15, 0, r0, c7, c6, 1		@ invalidate D entry
	add	r0, r0, #CACHE_DLINESIZE
	cmp	r0, r1
	blo	1b
	mcr	p15, 0, r0, c7, c10, 4		@ drain WB
	mov	pc, lr

/*
 *	dma_clean_range(start, end)
 *
 *	Clean the specified virtual address range.
 *
 *	- start	- virtual start address
 *	- end	- virtual end address
 *
 * (same as v4wb)
 */
ENTRY(arm925_dma_clean_range)
#ifndef CONFIG_CPU_DCACHE_WRITETHROUGH
	bic	r0, r0, #CACHE_DLINESIZE - 1
1:	mcr	p15, 0, r0, c7, c10, 1		@ clean D entry
	add	r0, r0, #CACHE_DLINESIZE
	cmp	r0, r1
	blo	1b
#endif
	mcr	p15, 0, r0, c7, c10, 4		@ drain WB
	mov	pc, lr

/*
 *	dma_flush_range(start, end)
 *
 *	Clean and invalidate the specified virtual address range.
 *
 *	- start	- virtual start address
 *	- end	- virtual end address
 */
ENTRY(arm925_dma_flush_range)
	bic	r0, r0, #CACHE_DLINESIZE - 1
1:
#ifndef CONFIG_CPU_DCACHE_WRITETHROUGH
	mcr	p15, 0, r0, c7, c14, 1		@ clean+invalidate D entry
#else
	mcr	p15, 0, r0, c7, c10, 1		@ clean D entry
#endif
	add	r0, r0, #CACHE_DLINESIZE
	cmp	r0, r1
	blo	1b
	mcr	p15, 0, r0, c7, c10, 4		@ drain WB
	mov	pc, lr

ENTRY(arm925_cache_fns)
	.long	arm925_flush_kern_cache_all
	.long	arm925_flush_user_cache_all
	.long	arm925_flush_user_cache_range
	.long	arm925_coherent_kern_range
	.long	arm925_coherent_user_range
	.long	arm925_flush_kern_dcache_page
	.long	arm925_dma_inv_range
	.long	arm925_dma_clean_range
	.long	arm925_dma_flush_range

ENTRY(cpu_arm925_dcache_clean_area)
#ifndef CONFIG_CPU_DCACHE_WRITETHROUGH
1:	mcr	p15, 0, r0, c7, c10, 1		@ clean D entry
	add	r0, r0, #CACHE_DLINESIZE
	subs	r1, r1, #CACHE_DLINESIZE
	bhi	1b
#endif
	mcr	p15, 0, r0, c7, c10, 4		@ drain WB
	mov	pc, lr

/* =============================== PageTable ============================== */

/*
 * cpu_arm925_switch_mm(pgd)
 *
 * Set the translation base pointer to be as described by pgd.
 *
 * pgd: new page tables
 */
	.align	5
ENTRY(cpu_arm925_switch_mm)
	mov	ip, #0
#ifdef CONFIG_CPU_DCACHE_WRITETHROUGH
	mcr	p15, 0, ip, c7, c6, 0		@ invalidate D cache
#else
	/* Flush entries in bothe segments at once, see NOTE1 above */
	mov	r3, #(CACHE_DENTRIES - 1) << 4	@ 256 entries in segment
2:	mcr	p15, 0, r3, c7, c14, 2		@ clean & invalidate D index
	subs	r3, r3, #1 << 4
	bcs	2b				@ entries 255 to 0
#endif
	mcr	p15, 0, ip, c7, c5, 0		@ invalidate I cache
	mcr	p15, 0, ip, c7, c10, 4		@ drain WB
	mcr	p15, 0, r0, c2, c0, 0		@ load page table pointer
	mcr	p15, 0, ip, c8, c7, 0		@ invalidate I & D TLBs
	mov	pc, lr

/*
 * cpu_arm925_set_pte(ptep, pte)
 *
 * Set a PTE and flush it out
 */
	.align	5
ENTRY(cpu_arm925_set_pte)
	str	r1, [r0], #-2048		@ linux version

	eor	r1, r1, #L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_WRITE | L_PTE_DIRTY

	bic	r2, r1, #PTE_SMALL_AP_MASK
	bic	r2, r2, #PTE_TYPE_MASK
	orr	r2, r2, #PTE_TYPE_SMALL

	tst	r1, #L_PTE_USER			@ User?
	orrne	r2, r2, #PTE_SMALL_AP_URO_SRW

	tst	r1, #L_PTE_WRITE | L_PTE_DIRTY	@ Write and Dirty?
	orreq	r2, r2, #PTE_SMALL_AP_UNO_SRW

	tst	r1, #L_PTE_PRESENT | L_PTE_YOUNG	@ Present and Young?
	movne	r2, #0

#ifdef CONFIG_CPU_DCACHE_WRITETHROUGH
	eor	r3, r2, #0x0a			@ C & small page?
	tst	r3, #0x0b
	biceq	r2, r2, #4
#endif
	str	r2, [r0]			@ hardware version
	mov	r0, r0
#ifndef CONFIG_CPU_DCACHE_WRITETHROUGH
	mcr	p15, 0, r0, c7, c10, 1		@ clean D entry
#endif
	mcr	p15, 0, r0, c7, c10, 4		@ drain WB
	mov	pc, lr

	__INIT

	.type	__arm925_setup, #function
__arm925_setup:
	mov	r0, #0
#if defined(CONFIG_CPU_ICACHE_STREAMING_DISABLE)
        orr     r0,r0,#1 << 7
#endif

	/* Transparent on, D-cache clean & flush mode. See  NOTE2 above */
        orr     r0,r0,#1 << 1			@ transparent mode on
        mcr     p15, 0, r0, c15, c1, 0          @ write TI config register

	mov	r0, #0
	mcr	p15, 0, r0, c7, c7		@ invalidate I,D caches on v4
	mcr	p15, 0, r0, c7, c10, 4		@ drain write buffer on v4
	mcr	p15, 0, r0, c8, c7		@ invalidate I,D TLBs on v4

#ifdef CONFIG_CPU_DCACHE_WRITETHROUGH
	mov	r0, #4				@ disable write-back on caches explicitly
	mcr	p15, 7, r0, c15, c0, 0
#endif

	mrc	p15, 0, r0, c1, c0		@ get control register v4
	ldr	r5, arm925_cr1_clear
	bic	r0, r0, r5
	ldr	r5, arm925_cr1_set
	orr	r0, r0, r5
#ifdef CONFIG_CPU_CACHE_ROUND_ROBIN
	orr	r0, r0, #0x4000			@ .1.. .... .... ....
#endif
	mov	pc, lr
	.size	__arm925_setup, . - __arm925_setup

	/*
	 *  R
	 * .RVI ZFRS BLDP WCAM
	 * .011 0001 ..11 1101
	 * 
	 */
	.type	arm925_cr1_clear, #object
	.type	arm925_cr1_set, #object
arm925_cr1_clear:
	.word	0x7f3f
arm925_cr1_set:
	.word	0x313d

	__INITDATA

/*
 * Purpose : Function pointers used to access above functions - all calls
 *	     come through these
 */
	.type	arm925_processor_functions, #object
arm925_processor_functions:
	.word	v4t_early_abort
	.word	cpu_arm925_proc_init
	.word	cpu_arm925_proc_fin
	.word	cpu_arm925_reset
	.word   cpu_arm925_do_idle
	.word	cpu_arm925_dcache_clean_area
	.word	cpu_arm925_switch_mm
	.word	cpu_arm925_set_pte
	.size	arm925_processor_functions, . - arm925_processor_functions

	.section ".rodata"

	.type	cpu_arch_name, #object
cpu_arch_name:
	.asciz	"armv4t"
	.size	cpu_arch_name, . - cpu_arch_name

	.type	cpu_elf_name, #object
cpu_elf_name:
	.asciz	"v4"
	.size	cpu_elf_name, . - cpu_elf_name

	.type	cpu_arm925_name, #object
cpu_arm925_name:
	.ascii	"ARM925T"
#ifndef CONFIG_CPU_ICACHE_DISABLE
	.ascii	"i"
#endif
#ifndef CONFIG_CPU_DCACHE_DISABLE
	.ascii	"d"
#ifdef CONFIG_CPU_DCACHE_WRITETHROUGH
	.ascii	"(wt)"
#else
	.ascii	"(wb)"
#endif
#ifdef CONFIG_CPU_CACHE_ROUND_ROBIN
	.ascii	"RR"
#endif
#endif
	.ascii	"\0"
	.size	cpu_arm925_name, . - cpu_arm925_name

	.align

	.section ".proc.info", #alloc, #execinstr

	.type	__arm925_proc_info,#object
__arm925_proc_info:
	.long	0x54029250
	.long	0xfffffff0
	.long   PMD_TYPE_SECT | \
		PMD_BIT4 | \
		PMD_SECT_AP_WRITE | \
		PMD_SECT_AP_READ
	b	__arm925_setup
	.long	cpu_arch_name
	.long	cpu_elf_name
	.long	HWCAP_SWP | HWCAP_HALF | HWCAP_THUMB
	.long	cpu_arm925_name
	.long	arm925_processor_functions
	.long	v4wbi_tlb_fns
	.long	v4wb_user_fns
	.long	arm925_cache_fns
	.size	__arm925_proc_info, . - __arm925_proc_info

	.type	__arm915_proc_info,#object
__arm915_proc_info:
	.long	0x54029150
	.long	0xfffffff0
	.long   PMD_TYPE_SECT | \
		PMD_BIT4 | \
		PMD_SECT_AP_WRITE | \
		PMD_SECT_AP_READ
	b	__arm925_setup
	.long	cpu_arch_name
	.long	cpu_elf_name
	.long	HWCAP_SWP | HWCAP_HALF | HWCAP_THUMB
	.long	cpu_arm925_name
	.long	arm925_processor_functions
	.long	v4wbi_tlb_fns
	.long	v4wb_user_fns
	.long	arm925_cache_fns
	.size	__arm925_proc_info, . - __arm925_proc_info