/* SPDX-License-Identifier: GPL-2.0-only */
/*
 *  linux/arch/arm/mm/arm940.S: utility functions for ARM940T
 *
 *  Copyright (C) 2004-2006 Hyok S. Choi (hyok.choi@samsung.com)
 */
#include <linux/linkage.h>
#include <linux/init.h>
#include <linux/cfi_types.h>
#include <linux/pgtable.h>
#include <asm/assembler.h>
#include <asm/hwcap.h>
#include <asm/pgtable-hwdef.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.
 */
SYM_TYPED_FUNC_START(cpu_arm940_proc_init)
        ret     lr
SYM_FUNC_END(cpu_arm940_proc_init)

SYM_TYPED_FUNC_START(cpu_arm940_switch_mm)
        ret     lr
SYM_FUNC_END(cpu_arm940_switch_mm)

/*
 * cpu_arm940_proc_fin()
 */
SYM_TYPED_FUNC_START(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
        ret     lr
SYM_FUNC_END(cpu_arm940_proc_fin)

/*
 * cpu_arm940_reset(loc)
 * Params  : r0 = address to jump to
 * Notes   : This sets up everything for a reset
 */
        .pushsection    .idmap.text, "ax"
SYM_TYPED_FUNC_START(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
        ret     r0
SYM_FUNC_END(cpu_arm940_reset)
        .popsection

/*
 * cpu_arm940_do_idle()
 */
        .align  5
SYM_TYPED_FUNC_START(cpu_arm940_do_idle)
        mcr     p15, 0, r0, c7, c0, 4           @ Wait for interrupt
        ret     lr
SYM_FUNC_END(cpu_arm940_do_idle)

/*
 *      flush_icache_all()
 *
 *      Unconditionally clean and invalidate the entire icache.
 */
SYM_TYPED_FUNC_START(arm940_flush_icache_all)
        mov     r0, #0
        mcr     p15, 0, r0, c7, c5, 0           @ invalidate I cache
        ret     lr
SYM_FUNC_END(arm940_flush_icache_all)

/*
 *      flush_user_cache_all()
 */
SYM_FUNC_ALIAS(arm940_flush_user_cache_all, arm940_flush_kern_cache_all)

/*
 *      flush_kern_cache_all()
 *
 *      Clean and invalidate the entire cache.
 */
SYM_TYPED_FUNC_START(arm940_flush_kern_cache_all)
        mov     r2, #VM_EXEC
        b       arm940_flush_user_cache_range
SYM_FUNC_END(arm940_flush_kern_cache_all)

/*
 *      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
 */
SYM_TYPED_FUNC_START(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
        ret     lr
SYM_FUNC_END(arm940_flush_user_cache_range)

/*
 *      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
 */
SYM_TYPED_FUNC_START(arm940_coherent_kern_range)
        b       arm940_flush_kern_dcache_area
SYM_FUNC_END(arm940_coherent_kern_range)

/*
 *      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
 */
SYM_TYPED_FUNC_START(arm940_coherent_user_range)
#ifdef CONFIG_CFI /* Fallthrough if !CFI */
        b       arm940_flush_kern_dcache_area
#endif
SYM_FUNC_END(arm940_coherent_user_range)

/*
 *      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
 */
SYM_TYPED_FUNC_START(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
        ret     lr
SYM_FUNC_END(arm940_flush_kern_dcache_area)

/*
 *      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
        ret     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:
SYM_TYPED_FUNC_START(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
        ret     lr
SYM_FUNC_END(cpu_arm940_dcache_clean_area)

/*
 *      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
 */
SYM_TYPED_FUNC_START(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
        ret     lr
SYM_FUNC_END(arm940_dma_flush_range)

/*
 *      dma_map_area(start, size, dir)
 *      - start - kernel virtual start address
 *      - size  - size of region
 *      - dir   - DMA direction
 */
SYM_TYPED_FUNC_START(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
SYM_FUNC_END(arm940_dma_map_area)

/*
 *      dma_unmap_area(start, size, dir)
 *      - start - kernel virtual start address
 *      - size  - size of region
 *      - dir   - DMA direction
 */
SYM_TYPED_FUNC_START(arm940_dma_unmap_area)
        ret     lr
SYM_FUNC_END(arm940_dma_unmap_area)

        .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     r7, =CONFIG_DRAM_SIZE >> 12     @ size of RAM (must be >= 4KB)
        pr_val  r3, r0, r7, #1
        mcr     p15, 0, r3, c6, c1, 0           @ set area 1, RAM
        mcr     p15, 0, r3, c6, c1, 1

        ldr     r0, =(CONFIG_FLASH_MEM_BASE & 0xFFFFF000) @ base[31:12] of FLASH
        ldr     r7, =CONFIG_FLASH_SIZE          @ size of FLASH (must be >= 4KB)
        pr_val  r3, r0, r6, #1
        mcr     p15, 0, r3, c6, c2, 0           @ set area 2, ROM/FLASH
        mcr     p15, 0, r3, 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

        ret     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", "a"

        .type   __arm940_proc_info,#object
__arm940_proc_info:
        .long   0x41009400
        .long   0xff00fff0
        .long   0
        initfn  __arm940_setup, __arm940_proc_info
        .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