proc-v7m.S
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/*
* linux/arch/arm/mm/proc-v7m.S
*
* Copyright (C) 2008 ARM Ltd.
* Copyright (C) 2001 Deep Blue Solutions Ltd.
*
* 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.
*
* This is the "shell" of the ARMv7-M processor support.
*/
#include <linux/linkage.h>
#include <asm/assembler.h>
#include <asm/v7m.h>
#include "proc-macros.S"
ENTRY(cpu_v7m_proc_init)
mov pc, lr
ENDPROC(cpu_v7m_proc_init)
ENTRY(cpu_v7m_proc_fin)
mov pc, lr
ENDPROC(cpu_v7m_proc_fin)
/*
* cpu_v7m_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_v7m_reset)
mov pc, r0
ENDPROC(cpu_v7m_reset)
/*
* cpu_v7m_do_idle()
*
* Idle the processor (eg, wait for interrupt).
*
* IRQs are already disabled.
*/
ENTRY(cpu_v7m_do_idle)
wfi
mov pc, lr
ENDPROC(cpu_v7m_do_idle)
ENTRY(cpu_v7m_dcache_clean_area)
mov pc, lr
ENDPROC(cpu_v7m_dcache_clean_area)
/*
* There is no MMU, so here is nothing to do.
*/
ENTRY(cpu_v7m_switch_mm)
mov pc, lr
ENDPROC(cpu_v7m_switch_mm)
.globl cpu_v7m_suspend_size
.equ cpu_v7m_suspend_size, 0
#ifdef CONFIG_ARM_CPU_SUSPEND
ENTRY(cpu_v7m_do_suspend)
mov pc, lr
ENDPROC(cpu_v7m_do_suspend)
ENTRY(cpu_v7m_do_resume)
mov pc, lr
ENDPROC(cpu_v7m_do_resume)
#endif
.section ".text.init", #alloc, #execinstr
/*
* __v7m_setup
*
* This should be able to cover all ARMv7-M cores.
*/
__v7m_setup:
@ Configure the vector table base address
ldr r0, =BASEADDR_V7M_SCB
ldr r12, =vector_table
str r12, [r0, V7M_SCB_VTOR]
@ enable UsageFault, BusFault and MemManage fault.
ldr r5, [r0, #V7M_SCB_SHCSR]
orr r5, #(V7M_SCB_SHCSR_USGFAULTENA | V7M_SCB_SHCSR_BUSFAULTENA | V7M_SCB_SHCSR_MEMFAULTENA)
str r5, [r0, #V7M_SCB_SHCSR]
@ Lower the priority of the SVC and PendSV exceptions
mov r5, #0x80000000
str r5, [r0, V7M_SCB_SHPR2] @ set SVC priority
mov r5, #0x00800000
str r5, [r0, V7M_SCB_SHPR3] @ set PendSV priority
@ SVC to run the kernel in this mode
adr r1, BSYM(1f)
ldr r5, [r12, #11 * 4] @ read the SVC vector entry
str r1, [r12, #11 * 4] @ write the temporary SVC vector entry
mov r6, lr @ save LR
mov r7, sp @ save SP
ldr sp, =__v7m_setup_stack_top
cpsie i
svc #0
1: cpsid i
str r5, [r12, #11 * 4] @ restore the original SVC vector entry
mov lr, r6 @ restore LR
mov sp, r7 @ restore SP
@ Special-purpose control register
mov r1, #1
msr control, r1 @ Thread mode has unpriviledged access
@ Configure the System Control Register to ensure 8-byte stack alignment
@ Note the STKALIGN bit is either RW or RAO.
ldr r12, [r0, V7M_SCB_CCR] @ system control register
orr r12, #V7M_SCB_CCR_STKALIGN
str r12, [r0, V7M_SCB_CCR]
mov pc, lr
ENDPROC(__v7m_setup)
define_processor_functions v7m, dabort=nommu_early_abort, pabort=legacy_pabort, nommu=1
.section ".rodata"
string cpu_arch_name, "armv7m"
string cpu_elf_name "v7m"
string cpu_v7m_name "ARMv7-M"
.section ".proc.info.init", #alloc, #execinstr
/*
* Match any ARMv7-M processor core.
*/
.type __v7m_proc_info, #object
__v7m_proc_info:
.long 0x000f0000 @ Required ID value
.long 0x000f0000 @ Mask for ID
.long 0 @ proc_info_list.__cpu_mm_mmu_flags
.long 0 @ proc_info_list.__cpu_io_mmu_flags
b __v7m_setup @ proc_info_list.__cpu_flush
.long cpu_arch_name
.long cpu_elf_name
.long HWCAP_HALF|HWCAP_THUMB|HWCAP_FAST_MULT
.long cpu_v7m_name
.long v7m_processor_functions @ proc_info_list.proc
.long 0 @ proc_info_list.tlb
.long 0 @ proc_info_list.user
.long nop_cache_fns @ proc_info_list.cache
.size __v7m_proc_info, . - __v7m_proc_info
__v7m_setup_stack:
.space 4 * 8 @ 8 registers
__v7m_setup_stack_top: