[ARM] nommu: add ARM940T core support

This patch adds ARM940T core support which has 4KB D-cache, 4KB I-cache
and a MPU.

Signed-off-by: Hyok S. Choi <hyok.choi@samsung.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 369 insertions, 0 deletions

diff --git a/arch/arm/mm/proc-arm940.S b/arch/arm/mm/proc-arm940.S
new file mode 100644
index 000000000000..14846ac2d0e6
--- /dev/null
+++ b/arch/arm/mm/proc-arm940.S
@@ -0,0 +1,369 @@
+/*
+ *  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/pgtable-hwdef.h>
+#include <asm/pgtable.h>
+#include <asm/procinfo.h>
+#include <asm/ptrace.h>
+
+/* 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)
+        stmfd   sp!, {lr}
+        mov     ip, #PSR_F_BIT | PSR_I_BIT | SVC_MODE
+        msr     cpsr_c, ip
+        bl      arm940_flush_kern_cache_all
+        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
+        ldmfd   sp!, {pc}
+
+/*
+ * cpu_arm940_reset(loc)
+ * Params  : r0 = address to jump to
+ * Notes   : This sets up everything for a reset
+ */
+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
+
+/*
+ * 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_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_page(void *page)
+ *
+ *      Ensure no D cache aliasing occurs, either with itself or
+ *      the I cache
+ *
+ *      - addr  - page aligned address
+ */
+ENTRY(arm940_flush_kern_dcache_page)
+        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, 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, ip, c7, c5, 0           @ invalidate I cache
+        mcr     p15, 0, ip, 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
+ */
+ENTRY(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
+ */
+ENTRY(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, c10, 2          @ clean 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
+
+ENTRY(arm940_cache_fns)
+        .long   arm940_flush_kern_cache_all
+        .long   arm940_flush_user_cache_all
+        .long   arm940_flush_user_cache_range
+        .long   arm940_coherent_kern_range
+        .long   arm940_coherent_user_range
+        .long   arm940_flush_kern_dcache_page
+        .long   arm940_dma_inv_range
+        .long   arm940_dma_clean_range
+        .long   arm940_dma_flush_range
+
+        __INIT
+
+        .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
+
+/*
+ * Purpose : Function pointers used to access above functions - all calls
+ *           come through these
+ */
+        .type   arm940_processor_functions, #object
+ENTRY(arm940_processor_functions)
+        .word   v4t_early_abort
+        .word   cpu_arm940_proc_init
+        .word   cpu_arm940_proc_fin
+        .word   cpu_arm940_reset
+        .word   cpu_arm940_do_idle
+        .word   cpu_arm940_dcache_clean_area
+        .word   cpu_arm940_switch_mm
+        .word   0               @ cpu_*_set_pte
+        .size   arm940_processor_functions, . - arm940_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_arm940_name, #object
+cpu_arm940_name:
+        .ascii  "ARM940T"
+        .size   cpu_arm940_name, . - cpu_arm940_name
+
+        .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
+