/*
   *  linux/arch/arm/mm/arm940.S: utility functions for ARM940T
   *
   *  Copyright (C) 2004-2006 Hyok S. Choi (hyok.choi@samsung.com)
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License version 2 as
   * published by the Free Software Foundation.
   *
   */
  #include <linux/linkage.h>
  #include <linux/init.h>
  #include <asm/assembler.h>
  #include <asm/hwcap.h>
  #include <asm/pgtable-hwdef.h>
  #include <asm/pgtable.h>
  #include <asm/ptrace.h>
  #include "proc-macros.S"
  
  /* ARM940T has a 4KB DCache comprising 256 lines of 4 words */
  #define CACHE_DLINESIZE	16
  #define CACHE_DSEGMENTS	4
  #define CACHE_DENTRIES	64
  
  	.text
  /*
   * cpu_arm940_proc_init()
   * cpu_arm940_switch_mm()
   *
   * These are not required.
   */
  ENTRY(cpu_arm940_proc_init)
  ENTRY(cpu_arm940_switch_mm)
  	mov	pc, lr
  
  /*
   * cpu_arm940_proc_fin()
   */
  ENTRY(cpu_arm940_proc_fin)
  	mrc	p15, 0, r0, c1, c0, 0		@ ctrl register
  	bic	r0, r0, #0x00001000		@ i-cache
  	bic	r0, r0, #0x00000004		@ d-cache
  	mcr	p15, 0, r0, c1, c0, 0		@ disable caches
  	mov	pc, lr
  
  /*
   * cpu_arm940_reset(loc)
   * Params  : r0 = address to jump to
   * Notes   : This sets up everything for a reset
   */
  	.pushsection	.idmap.text, "ax"
  ENTRY(cpu_arm940_reset)
  	mov	ip, #0
  	mcr	p15, 0, ip, c7, c5, 0		@ flush I cache
  	mcr	p15, 0, ip, c7, c6, 0		@ flush D cache
  	mcr	p15, 0, ip, c7, c10, 4		@ drain WB
  	mrc	p15, 0, ip, c1, c0, 0		@ ctrl register
  	bic	ip, ip, #0x00000005		@ .............c.p
  	bic	ip, ip, #0x00001000		@ i-cache
  	mcr	p15, 0, ip, c1, c0, 0		@ ctrl register
  	mov	pc, r0
  ENDPROC(cpu_arm940_reset)
  	.popsection
  
  /*
   * cpu_arm940_do_idle()
   */
  	.align	5
  ENTRY(cpu_arm940_do_idle)
  	mcr	p15, 0, r0, c7, c0, 4		@ Wait for interrupt
  	mov	pc, lr
  
  /*
   *	flush_icache_all()
   *
   *	Unconditionally clean and invalidate the entire icache.
   */
  ENTRY(arm940_flush_icache_all)
  	mov	r0, #0
  	mcr	p15, 0, r0, c7, c5, 0		@ invalidate I cache
  	mov	pc, lr
  ENDPROC(arm940_flush_icache_all)
  
  /*
   *	flush_user_cache_all()
   */
  ENTRY(arm940_flush_user_cache_all)
  	/* FALLTHROUGH */
  
  /*
   *	flush_kern_cache_all()
   *
   *	Clean and invalidate the entire cache.
   */
  ENTRY(arm940_flush_kern_cache_all)
  	mov	r2, #VM_EXEC
  	/* FALLTHROUGH */
  
  /*
   *	flush_user_cache_range(start, end, flags)
   *
   *	There is no efficient way to flush a range of cache entries
   *	in the specified address range. Thus, flushes all.
   *
   *	- start	- start address (inclusive)
   *	- end	- end address (exclusive)
   *	- flags	- vm_flags describing address space
   */
  ENTRY(arm940_flush_user_cache_range)
  	mov	ip, #0
  #ifdef CONFIG_CPU_DCACHE_WRITETHROUGH
  	mcr	p15, 0, ip, c7, c6, 0		@ flush D cache
  #else
  	mov	r1, #(CACHE_DSEGMENTS - 1) << 4	@ 4 segments
  1:	orr	r3, r1, #(CACHE_DENTRIES - 1) << 26 @ 64 entries
  2:	mcr	p15, 0, r3, c7, c14, 2		@ clean/flush D index
  	subs	r3, r3, #1 << 26
  	bcs	2b				@ entries 63 to 0
  	subs	r1, r1, #1 << 4
  	bcs	1b				@ segments 3 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
  
  /*
   *	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(arm940_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(arm940_coherent_user_range)
  	/* FALLTHROUGH */
  
  /*
   *	flush_kern_dcache_area(void *addr, size_t size)
   *
   *	Ensure no D cache aliasing occurs, either with itself or
   *	the I cache
   *
   *	- addr	- kernel address
   *	- size	- region size
   */
  ENTRY(arm940_flush_kern_dcache_area)
  	mov	r0, #0
  	mov	r1, #(CACHE_DSEGMENTS - 1) << 4	@ 4 segments
  1:	orr	r3, r1, #(CACHE_DENTRIES - 1) << 26 @ 64 entries
  2:	mcr	p15, 0, r3, c7, c14, 2		@ clean/flush D index
  	subs	r3, r3, #1 << 26
  	bcs	2b				@ entries 63 to 0
  	subs	r1, r1, #1 << 4
  	bcs	1b				@ segments 7 to 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)
   *
   *	There is no efficient way to invalidate a specifid virtual
   *	address range. Thus, invalidates all.
   *
   *	- start	- virtual start address
   *	- end	- virtual end address
   */
  arm940_dma_inv_range:
  	mov	ip, #0
  	mov	r1, #(CACHE_DSEGMENTS - 1) << 4	@ 4 segments
  1:	orr	r3, r1, #(CACHE_DENTRIES - 1) << 26 @ 64 entries
  2:	mcr	p15, 0, r3, c7, c6, 2		@ flush D entry
  	subs	r3, r3, #1 << 26
  	bcs	2b				@ entries 63 to 0
  	subs	r1, r1, #1 << 4
  	bcs	1b				@ segments 7 to 0
  	mcr	p15, 0, ip, c7, c10, 4		@ drain WB
  	mov	pc, lr
  
  /*
   *	dma_clean_range(start, end)
   *
   *	There is no efficient way to clean a specifid virtual
   *	address range. Thus, cleans all.
   *
   *	- start	- virtual start address
   *	- end	- virtual end address
   */
  arm940_dma_clean_range:
  ENTRY(cpu_arm940_dcache_clean_area)
  	mov	ip, #0
  #ifndef CONFIG_CPU_DCACHE_WRITETHROUGH
  	mov	r1, #(CACHE_DSEGMENTS - 1) << 4	@ 4 segments
  1:	orr	r3, r1, #(CACHE_DENTRIES - 1) << 26 @ 64 entries
  2:	mcr	p15, 0, r3, c7, c10, 2		@ clean D entry
  	subs	r3, r3, #1 << 26
  	bcs	2b				@ entries 63 to 0
  	subs	r1, r1, #1 << 4
  	bcs	1b				@ segments 7 to 0
  #endif
  	mcr	p15, 0, ip, c7, c10, 4		@ drain WB
  	mov	pc, lr
  
  /*
   *	dma_flush_range(start, end)
   *
   *	There is no efficient way to clean and invalidate a specifid
   *	virtual address range.
   *
   *	- start	- virtual start address
   *	- end	- virtual end address
   */
  ENTRY(arm940_dma_flush_range)
  	mov	ip, #0
  	mov	r1, #(CACHE_DSEGMENTS - 1) << 4	@ 4 segments
  1:	orr	r3, r1, #(CACHE_DENTRIES - 1) << 26 @ 64 entries
  2:
  #ifndef CONFIG_CPU_DCACHE_WRITETHROUGH
  	mcr	p15, 0, r3, c7, c14, 2		@ clean/flush D entry
  #else
  	mcr	p15, 0, r3, c7, c6, 2		@ invalidate D entry
  #endif
  	subs	r3, r3, #1 << 26
  	bcs	2b				@ entries 63 to 0
  	subs	r1, r1, #1 << 4
  	bcs	1b				@ segments 7 to 0
  	mcr	p15, 0, ip, c7, c10, 4		@ drain WB
  	mov	pc, lr
  
  /*
   *	dma_map_area(start, size, dir)
   *	- start	- kernel virtual start address
   *	- size	- size of region
   *	- dir	- DMA direction
   */
  ENTRY(arm940_dma_map_area)
  	add	r1, r1, r0
  	cmp	r2, #DMA_TO_DEVICE
  	beq	arm940_dma_clean_range
  	bcs	arm940_dma_inv_range
  	b	arm940_dma_flush_range
  ENDPROC(arm940_dma_map_area)
  
  /*
   *	dma_unmap_area(start, size, dir)
   *	- start	- kernel virtual start address
   *	- size	- size of region
   *	- dir	- DMA direction
   */
  ENTRY(arm940_dma_unmap_area)
  	mov	pc, lr
  ENDPROC(arm940_dma_unmap_area)
  
  	.globl	arm940_flush_kern_cache_louis
  	.equ	arm940_flush_kern_cache_louis, arm940_flush_kern_cache_all
  
  	@ define struct cpu_cache_fns (see <asm/cacheflush.h> and proc-macros.S)
  	define_cache_functions arm940
  
  	.type	__arm940_setup, #function
  __arm940_setup:
  	mov	r0, #0
  	mcr	p15, 0, r0, c7, c5, 0		@ invalidate I cache
  	mcr	p15, 0, r0, c7, c6, 0		@ invalidate D cache
  	mcr	p15, 0, r0, c7, c10, 4		@ drain WB
  
  	mcr	p15, 0, r0, c6, c3, 0		@ disable data area 3~7
  	mcr	p15, 0, r0, c6, c4, 0
  	mcr	p15, 0, r0, c6, c5, 0
  	mcr	p15, 0, r0, c6, c6, 0
  	mcr	p15, 0, r0, c6, c7, 0
  
  	mcr	p15, 0, r0, c6, c3, 1		@ disable instruction area 3~7
  	mcr	p15, 0, r0, c6, c4, 1
  	mcr	p15, 0, r0, c6, c5, 1
  	mcr	p15, 0, r0, c6, c6, 1
  	mcr	p15, 0, r0, c6, c7, 1
  
  	mov	r0, #0x0000003F			@ base = 0, size = 4GB
  	mcr	p15, 0, r0, c6,	c0, 0		@ set area 0, default
  	mcr	p15, 0, r0, c6,	c0, 1
  
  	ldr	r0, =(CONFIG_DRAM_BASE & 0xFFFFF000) @ base[31:12] of RAM
  	ldr	r1, =(CONFIG_DRAM_SIZE >> 12)	@ size of RAM (must be >= 4KB)
  	mov	r2, #10				@ 11 is the minimum (4KB)
  1:	add	r2, r2, #1			@ area size *= 2
  	mov	r1, r1, lsr #1
  	bne	1b				@ count not zero r-shift
  	orr	r0, r0, r2, lsl #1		@ the area register value
  	orr	r0, r0, #1			@ set enable bit
  	mcr	p15, 0, r0, c6,	c1, 0		@ set area 1, RAM
  	mcr	p15, 0, r0, c6,	c1, 1
  
  	ldr	r0, =(CONFIG_FLASH_MEM_BASE & 0xFFFFF000) @ base[31:12] of FLASH
  	ldr	r1, =(CONFIG_FLASH_SIZE >> 12)	@ size of FLASH (must be >= 4KB)
  	mov	r2, #10				@ 11 is the minimum (4KB)
  1:	add	r2, r2, #1			@ area size *= 2
  	mov	r1, r1, lsr #1
  	bne	1b				@ count not zero r-shift
  	orr	r0, r0, r2, lsl #1		@ the area register value
  	orr	r0, r0, #1			@ set enable bit
  	mcr	p15, 0, r0, c6,	c2, 0		@ set area 2, ROM/FLASH
  	mcr	p15, 0, r0, c6,	c2, 1
  
  	mov	r0, #0x06
  	mcr	p15, 0, r0, c2, c0, 0		@ Region 1&2 cacheable
  	mcr	p15, 0, r0, c2, c0, 1
  #ifdef CONFIG_CPU_DCACHE_WRITETHROUGH
  	mov	r0, #0x00			@ disable whole write buffer
  #else
  	mov	r0, #0x02			@ Region 1 write bufferred
  #endif
  	mcr	p15, 0, r0, c3, c0, 0
  
  	mov	r0, #0x10000
  	sub	r0, r0, #1			@ r0 = 0xffff
  	mcr	p15, 0, r0, c5, c0, 0		@ all read/write access
  	mcr	p15, 0, r0, c5, c0, 1
  
  	mrc	p15, 0, r0, c1, c0		@ get control register
  	orr	r0, r0, #0x00001000		@ I-cache
  	orr	r0, r0, #0x00000005		@ MPU/D-cache
  
  	mov	pc, lr
  
  	.size	__arm940_setup, . - __arm940_setup
  
  	__INITDATA
  
  	@ define struct processor (see <asm/proc-fns.h> and proc-macros.S)
  	define_processor_functions arm940, dabort=nommu_early_abort, pabort=legacy_pabort, nommu=1
  
  	.section ".rodata"
  
  	string	cpu_arch_name, "armv4t"
  	string	cpu_elf_name, "v4"
  	string	cpu_arm940_name, "ARM940T"
  
  	.align
  
  	.section ".proc.info.init", #alloc, #execinstr
  
  	.type	__arm940_proc_info,#object
  __arm940_proc_info:
  	.long	0x41009400
  	.long	0xff00fff0
  	.long	0
  	b	__arm940_setup
  	.long	cpu_arch_name
  	.long	cpu_elf_name
  	.long	HWCAP_SWP | HWCAP_HALF | HWCAP_THUMB
  	.long	cpu_arm940_name
  	.long	arm940_processor_functions
  	.long	0
  	.long	0
  	.long	arm940_cache_fns
  	.size	__arm940_proc_info, . - __arm940_proc_info