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kernel/linux-imx6_3.14.28/arch/arm/mm/proc-v7m.S 3.81 KB
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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: