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22b1908610
linux/arch/arm/mm/proc-sa1100.S
Russell King 22b1908610 [ARM] nommu: provide a way for correct control register value selection 
Most MMU-based CPUs have a restriction on the setting of the data cache
enable and mmu enable bits in the control register, whereby if the data
cache is enabled, the MMU must also be enabled.  Enabling the data
cache without the MMU is an invalid combination.

However, there are CPUs where the data cache can be enabled without the
MMU.

In order to allow these CPUs to take advantage of that, provide a
method whereby each proc-*.S file defines the control regsiter value
for use with nommu (with the MMU disabled.)  Later on, when we add
support for enabling the MMU on these devices, we can adjust the
"crval" macro to also enable the data cache for nommu.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2006-06-29 15:09:57 +01:00

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/*
* linux/arch/arm/mm/proc-sa1100.S
*
* Copyright (C) 1997-2002 Russell King
* hacked for non-paged-MM by Hyok S. Choi, 2003.
*
* 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.
*
* MMU functions for SA110
*
* These are the low level assembler for performing cache and TLB
* functions on the StrongARM-1100 and StrongARM-1110.
*
* Note that SA1100 and SA1110 share everything but their name and CPU ID.
*
* 12-jun-2000, Erik Mouw (J.A.K.Mouw@its.tudelft.nl):
* Flush the read buffer at context switches
*/
#include <linux/linkage.h>
#include <linux/init.h>
#include <asm/assembler.h>
#include <asm/asm-offsets.h>
#include <asm/procinfo.h>
#include <asm/hardware.h>
#include <asm/pgtable-hwdef.h>
#include <asm/pgtable.h>
/*
* the cache line size of the I and D cache
*/
#define DCACHELINESIZE 32
__INIT
/*
* cpu_sa1100_proc_init()
*/
ENTRY(cpu_sa1100_proc_init)
mov r0, #0
mcr p15, 0, r0, c15, c1, 2 @ Enable clock switching
mcr p15, 0, r0, c9, c0, 5 @ Allow read-buffer operations from userland
mov pc, lr
.previous
/*
* cpu_sa1100_proc_fin()
*
* Prepare the CPU for reset:
* - Disable interrupts
* - Clean and turn off caches.
*/
ENTRY(cpu_sa1100_proc_fin)
stmfd sp!, {lr}
mov ip, #PSR_F_BIT | PSR_I_BIT | SVC_MODE
msr cpsr_c, ip
bl v4wb_flush_kern_cache_all
mcr p15, 0, ip, c15, c2, 2 @ Disable clock switching
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_sa1100_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_sa1100_reset)
mov ip, #0
mcr p15, 0, ip, c7, c7, 0 @ invalidate I,D caches
mcr p15, 0, ip, c7, c10, 4 @ drain WB
#ifdef CONFIG_MMU
mcr p15, 0, ip, c8, c7, 0 @ invalidate I & D TLBs
#endif
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_sa1100_do_idle(type)
*
* Cause the processor to idle
*
* type: call type:
* 0 = slow idle
* 1 = fast idle
* 2 = switch to slow processor clock
* 3 = switch to fast processor clock
*/
.align 5
ENTRY(cpu_sa1100_do_idle)
mov r0, r0 @ 4 nop padding
mov r0, r0
mov r0, r0
mov r0, r0 @ 4 nop padding
mov r0, r0
mov r0, r0
mov r0, #0
ldr r1, =UNCACHEABLE_ADDR @ ptr to uncacheable address
@ --- aligned to a cache line
mcr p15, 0, r0, c15, c2, 2 @ disable clock switching
ldr r1, [r1, #0] @ force switch to MCLK
mcr p15, 0, r0, c15, c8, 2 @ wait for interrupt
mov r0, r0 @ safety
mcr p15, 0, r0, c15, c1, 2 @ enable clock switching
mov pc, lr
/* ================================= CACHE ================================ */
/*
* cpu_sa1100_dcache_clean_area(addr,sz)
*
* Clean the specified entry of any caches such that the MMU
* translation fetches will obtain correct data.
*
* addr: cache-unaligned virtual address
*/
.align 5
ENTRY(cpu_sa1100_dcache_clean_area)
1: mcr p15, 0, r0, c7, c10, 1 @ clean D entry
add r0, r0, #DCACHELINESIZE
subs r1, r1, #DCACHELINESIZE
bhi 1b
mov pc, lr
/* =============================== PageTable ============================== */
/*
* cpu_sa1100_switch_mm(pgd)
*
* Set the translation base pointer to be as described by pgd.
*
* pgd: new page tables
*/
.align 5
ENTRY(cpu_sa1100_switch_mm)
#ifdef CONFIG_MMU
str lr, [sp, #-4]!
bl v4wb_flush_kern_cache_all @ clears IP
mcr p15, 0, ip, c9, c0, 0 @ invalidate RB
mcr p15, 0, r0, c2, c0, 0 @ load page table pointer
mcr p15, 0, ip, c8, c7, 0 @ invalidate I & D TLBs
ldr pc, [sp], #4
#else
mov pc, lr
#endif
/*
* cpu_sa1100_set_pte(ptep, pte)
*
* Set a PTE and flush it out
*/
.align 5
ENTRY(cpu_sa1100_set_pte)
#ifdef CONFIG_MMU
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
str r2, [r0] @ hardware version
mov r0, r0
mcr p15, 0, r0, c7, c10, 1 @ clean D entry
mcr p15, 0, r0, c7, c10, 4 @ drain WB
#endif
mov pc, lr
__INIT
.type __sa1100_setup, #function
__sa1100_setup:
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
#ifdef CONFIG_MMU
mcr p15, 0, r0, c8, c7 @ invalidate I,D TLBs on v4
#endif
adr r5, sa1100_crval
ldmia r5, {r5, r6}
mrc p15, 0, r0, c1, c0 @ get control register v4
bic r0, r0, r5
orr r0, r0, r6
mov pc, lr
.size __sa1100_setup, . - __sa1100_setup
/*
* R
* .RVI ZFRS BLDP WCAM
* ..11 0001 ..11 1101
*
*/
.type sa1100_crval, #object
sa1100_crval:
crval clear=0x00003f3f, mmuset=0x0000313d, ucset=0x00001130
__INITDATA
/*
* Purpose : Function pointers used to access above functions - all calls
* come through these
*/
/*
* SA1100 and SA1110 share the same function calls
*/
.type sa1100_processor_functions, #object
ENTRY(sa1100_processor_functions)
.word v4_early_abort
.word cpu_sa1100_proc_init
.word cpu_sa1100_proc_fin
.word cpu_sa1100_reset
.word cpu_sa1100_do_idle
.word cpu_sa1100_dcache_clean_area
.word cpu_sa1100_switch_mm
.word cpu_sa1100_set_pte
.size sa1100_processor_functions, . - sa1100_processor_functions
.section ".rodata"
.type cpu_arch_name, #object
cpu_arch_name:
.asciz "armv4"
.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_sa1100_name, #object
cpu_sa1100_name:
.asciz "StrongARM-1100"
.size cpu_sa1100_name, . - cpu_sa1100_name
.type cpu_sa1110_name, #object
cpu_sa1110_name:
.asciz "StrongARM-1110"
.size cpu_sa1110_name, . - cpu_sa1110_name
.align
.section ".proc.info.init", #alloc, #execinstr
.type __sa1100_proc_info,#object
__sa1100_proc_info:
.long 0x4401a110
.long 0xfffffff0
.long PMD_TYPE_SECT | \
PMD_SECT_BUFFERABLE | \
PMD_SECT_CACHEABLE | \
PMD_SECT_AP_WRITE | \
PMD_SECT_AP_READ
b __sa1100_setup
.long cpu_arch_name
.long cpu_elf_name
.long HWCAP_SWP | HWCAP_HALF | HWCAP_26BIT | HWCAP_FAST_MULT
.long cpu_sa1100_name
.long sa1100_processor_functions
.long v4wb_tlb_fns
.long v4_mc_user_fns
.long v4wb_cache_fns
.size __sa1100_proc_info, . - __sa1100_proc_info
.type __sa1110_proc_info,#object
__sa1110_proc_info:
.long 0x6901b110
.long 0xfffffff0
.long PMD_TYPE_SECT | \
PMD_SECT_BUFFERABLE | \
PMD_SECT_CACHEABLE | \
PMD_SECT_AP_WRITE | \
PMD_SECT_AP_READ
b __sa1100_setup
.long cpu_arch_name
.long cpu_elf_name
.long HWCAP_SWP | HWCAP_HALF | HWCAP_26BIT | HWCAP_FAST_MULT
.long cpu_sa1110_name
.long sa1100_processor_functions
.long v4wb_tlb_fns
.long v4_mc_user_fns
.long v4wb_cache_fns
.size __sa1110_proc_info, . - __sa1110_proc_info
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