arch/arm/mm/proc-v7m.S - linux - Git at Google

 /* SPDX-License-Identifier: GPL-2.0-only */
 /*
  *  linux/arch/arm/mm/proc-v7m.S
  *
  *  Copyright (C) 2008 ARM Ltd.
  *  Copyright (C) 2001 Deep Blue Solutions Ltd.
  *
  *  This is the "shell" of the ARMv7-M processor support.
  */
 #include <linux/linkage.h>
 #include <asm/assembler.h>
 #include <asm/memory.h>
 #include <asm/v7m.h>
 #include "proc-macros.S"

 ENTRY(cpu_v7m_proc_init)
 	ret	lr
 ENDPROC(cpu_v7m_proc_init)

 ENTRY(cpu_v7m_proc_fin)
 	ret	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)
 	ret	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
 	ret	lr
 ENDPROC(cpu_v7m_do_idle)

 ENTRY(cpu_v7m_dcache_clean_area)
 	ret	lr
 ENDPROC(cpu_v7m_dcache_clean_area)

 /*
  * There is no MMU, so here is nothing to do.
  */
 ENTRY(cpu_v7m_switch_mm)
 	ret	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)
 	ret	lr
 ENDPROC(cpu_v7m_do_suspend)

 ENTRY(cpu_v7m_do_resume)
 	ret	lr
 ENDPROC(cpu_v7m_do_resume)
 #endif

 ENTRY(cpu_cm7_dcache_clean_area)
 	dcache_line_size r2, r3
 	movw	r3, #:lower16:BASEADDR_V7M_SCB + V7M_SCB_DCCMVAC
 	movt	r3, #:upper16:BASEADDR_V7M_SCB + V7M_SCB_DCCMVAC

 1:	str	r0, [r3]		@ clean D entry
 	add	r0, r0, r2
 	subs	r1, r1, r2
 	bhi	1b
 	dsb
 	ret	lr
 ENDPROC(cpu_cm7_dcache_clean_area)

 ENTRY(cpu_cm7_proc_fin)
 	movw	r2, #:lower16:(BASEADDR_V7M_SCB + V7M_SCB_CCR)
 	movt	r2, #:upper16:(BASEADDR_V7M_SCB + V7M_SCB_CCR)
 	ldr	r0, [r2]
 	bic	r0, r0, #(V7M_SCB_CCR_DC | V7M_SCB_CCR_IC)
 	str	r0, [r2]
 	ret	lr
 ENDPROC(cpu_cm7_proc_fin)

 	.section ".init.text", #alloc, #execinstr

 __v7m_cm7_setup:
 	mov	r8, #(V7M_SCB_CCR_DC | V7M_SCB_CCR_IC| V7M_SCB_CCR_BP)
 	b	__v7m_setup_cont
 /*
  *	__v7m_setup
  *
  *	This should be able to cover all ARMv7-M cores.
  */
 __v7m_setup:
 	mov	r8, 0

 __v7m_setup_cont:
 	@ 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 switch to handler mode. Notice that this requires sp to
 	@ point to writeable memory because the processor saves
 	@ some registers to the stack.
 	badr	r1, 1f
 	ldr	r5, [r12, #11 * 4]	@ read the SVC vector entry
 	str	r1, [r12, #11 * 4]	@ write the temporary SVC vector entry
 	dsb
 	mov	r6, lr			@ save LR
 	ldr	sp, =init_thread_union + THREAD_START_SP
 	stmia	sp, {r0-r3, r12}
 	cpsie	i
 	svc	#0
 1:	cpsid	i
 	ldr	r0, =exc_ret
 	orr	lr, lr, #EXC_RET_THREADMODE_PROCESSSTACK
 	str	lr, [r0]
 	ldmia	sp, {r0-r3, r12}
 	str	r5, [r12, #11 * 4]	@ restore the original SVC vector entry
 	mov	lr, r6			@ restore LR

 	@ Special-purpose control register
 	mov	r1, #1
 	msr	control, r1		@ Thread mode has unpriviledged access

 	@ Configure caches (if implemented)
 	teq     r8, #0
 	stmiane	sp, {r0-r6, lr}		@ v7m_invalidate_l1 touches r0-r6
 	blne	v7m_invalidate_l1
 	teq     r8, #0			@ re-evalutae condition
 	ldmiane	sp, {r0-r6, lr}

 	@ Configure the System Control Register to ensure 8-byte stack alignment
 	@ Note the STKALIGN bit is either RW or RAO.
 	ldr	r0, [r0, V7M_SCB_CCR]   @ system control register
 	orr	r0, #V7M_SCB_CCR_STKALIGN
 	orr	r0, r0, r8

 	ret	lr
 ENDPROC(__v7m_setup)

 /*
  * Cortex-M7 processor functions
  */
 	globl_equ	cpu_cm7_proc_init,	cpu_v7m_proc_init
 	globl_equ	cpu_cm7_reset,		cpu_v7m_reset
 	globl_equ	cpu_cm7_do_idle,	cpu_v7m_do_idle
 	globl_equ	cpu_cm7_switch_mm,	cpu_v7m_switch_mm

 	define_processor_functions v7m, dabort=nommu_early_abort, pabort=legacy_pabort, nommu=1
 	define_processor_functions cm7, 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

 .macro __v7m_proc name, initfunc, cache_fns = nop_cache_fns, hwcaps = 0,  proc_fns = v7m_processor_functions
 	.long	0			/* proc_info_list.__cpu_mm_mmu_flags */
 	.long	0			/* proc_info_list.__cpu_io_mmu_flags */
 	initfn	\initfunc, \name
 	.long	cpu_arch_name
 	.long	cpu_elf_name
 	.long	HWCAP_HALF | HWCAP_THUMB | HWCAP_FAST_MULT | \hwcaps
 	.long	cpu_v7m_name
 	.long   \proc_fns
 	.long	0			/* proc_info_list.tlb */
 	.long	0			/* proc_info_list.user */
 	.long	\cache_fns
 .endm

 	/*
 	 * Match ARM Cortex-M7 processor.
 	 */
 	.type	__v7m_cm7_proc_info, #object
 __v7m_cm7_proc_info:
 	.long	0x410fc270		/* ARM Cortex-M7 0xC27 */
 	.long	0xff0ffff0		/* Mask off revision, patch release */
 	__v7m_proc __v7m_cm7_proc_info, __v7m_cm7_setup, hwcaps = HWCAP_EDSP, cache_fns = v7m_cache_fns, proc_fns = cm7_processor_functions
 	.size	__v7m_cm7_proc_info, . - __v7m_cm7_proc_info

 	/*
 	 * Match ARM Cortex-M4 processor.
 	 */
 	.type	__v7m_cm4_proc_info, #object
 __v7m_cm4_proc_info:
 	.long	0x410fc240		/* ARM Cortex-M4 0xC24 */
 	.long	0xff0ffff0		/* Mask off revision, patch release */
 	__v7m_proc __v7m_cm4_proc_info, __v7m_setup, hwcaps = HWCAP_EDSP
 	.size	__v7m_cm4_proc_info, . - __v7m_cm4_proc_info

 	/*
 	 * Match ARM Cortex-M3 processor.
 	 */
 	.type	__v7m_cm3_proc_info, #object
 __v7m_cm3_proc_info:
 	.long	0x410fc230		/* ARM Cortex-M3 0xC23 */
 	.long	0xff0ffff0		/* Mask off revision, patch release */
 	__v7m_proc __v7m_cm3_proc_info, __v7m_setup
 	.size	__v7m_cm3_proc_info, . - __v7m_cm3_proc_info

 	/*
 	 * Match any ARMv7-M processor core.
 	 */
 	.type	__v7m_proc_info, #object
 __v7m_proc_info:
 	.long	0x000f0000		@ Required ID value
 	.long	0x000f0000		@ Mask for ID
 	__v7m_proc __v7m_proc_info, __v7m_setup
 	.size	__v7m_proc_info, . - __v7m_proc_info
	/* SPDX-License-Identifier: GPL-2.0-only */
	/*
	* linux/arch/arm/mm/proc-v7m.S
	*
	* Copyright (C) 2008 ARM Ltd.
	* Copyright (C) 2001 Deep Blue Solutions Ltd.
	*
	* This is the "shell" of the ARMv7-M processor support.
	*/
	#include <linux/linkage.h>
	#include <asm/assembler.h>
	#include <asm/memory.h>
	#include <asm/v7m.h>
	#include "proc-macros.S"

	ENTRY(cpu_v7m_proc_init)
	ret lr
	ENDPROC(cpu_v7m_proc_init)

	ENTRY(cpu_v7m_proc_fin)
	ret 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)
	ret 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
	ret lr
	ENDPROC(cpu_v7m_do_idle)

	ENTRY(cpu_v7m_dcache_clean_area)
	ret lr
	ENDPROC(cpu_v7m_dcache_clean_area)

	/*
	* There is no MMU, so here is nothing to do.
	*/
	ENTRY(cpu_v7m_switch_mm)
	ret 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)
	ret lr
	ENDPROC(cpu_v7m_do_suspend)

	ENTRY(cpu_v7m_do_resume)
	ret lr
	ENDPROC(cpu_v7m_do_resume)
	#endif

	ENTRY(cpu_cm7_dcache_clean_area)
	dcache_line_size r2, r3
	movw r3, #:lower16:BASEADDR_V7M_SCB + V7M_SCB_DCCMVAC
	movt r3, #:upper16:BASEADDR_V7M_SCB + V7M_SCB_DCCMVAC

	1: str r0, [r3] @ clean D entry
	add r0, r0, r2
	subs r1, r1, r2
	bhi 1b
	dsb
	ret lr
	ENDPROC(cpu_cm7_dcache_clean_area)

	ENTRY(cpu_cm7_proc_fin)
	movw r2, #:lower16:(BASEADDR_V7M_SCB + V7M_SCB_CCR)
	movt r2, #:upper16:(BASEADDR_V7M_SCB + V7M_SCB_CCR)
	ldr r0, [r2]
	bic r0, r0, #(V7M_SCB_CCR_DC \| V7M_SCB_CCR_IC)
	str r0, [r2]
	ret lr
	ENDPROC(cpu_cm7_proc_fin)

	.section ".init.text", #alloc, #execinstr

	__v7m_cm7_setup:
	mov r8, #(V7M_SCB_CCR_DC \| V7M_SCB_CCR_IC\| V7M_SCB_CCR_BP)
	b __v7m_setup_cont
	/*
	* __v7m_setup
	*
	* This should be able to cover all ARMv7-M cores.
	*/
	__v7m_setup:
	mov r8, 0

	__v7m_setup_cont:
	@ 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 switch to handler mode. Notice that this requires sp to
	@ point to writeable memory because the processor saves
	@ some registers to the stack.
	badr r1, 1f
	ldr r5, [r12, #11 * 4] @ read the SVC vector entry
	str r1, [r12, #11 * 4] @ write the temporary SVC vector entry
	dsb
	mov r6, lr @ save LR
	ldr sp, =init_thread_union + THREAD_START_SP
	stmia sp, {r0-r3, r12}
	cpsie i
	svc #0
	1: cpsid i
	ldr r0, =exc_ret
	orr lr, lr, #EXC_RET_THREADMODE_PROCESSSTACK
	str lr, [r0]
	ldmia sp, {r0-r3, r12}
	str r5, [r12, #11 * 4] @ restore the original SVC vector entry
	mov lr, r6 @ restore LR

	@ Special-purpose control register
	mov r1, #1
	msr control, r1 @ Thread mode has unpriviledged access

	@ Configure caches (if implemented)
	teq r8, #0
	stmiane sp, {r0-r6, lr} @ v7m_invalidate_l1 touches r0-r6
	blne v7m_invalidate_l1
	teq r8, #0 @ re-evalutae condition
	ldmiane sp, {r0-r6, lr}

	@ Configure the System Control Register to ensure 8-byte stack alignment
	@ Note the STKALIGN bit is either RW or RAO.
	ldr r0, [r0, V7M_SCB_CCR] @ system control register
	orr r0, #V7M_SCB_CCR_STKALIGN
	orr r0, r0, r8

	ret lr
	ENDPROC(__v7m_setup)

	/*
	* Cortex-M7 processor functions
	*/
	globl_equ cpu_cm7_proc_init, cpu_v7m_proc_init
	globl_equ cpu_cm7_reset, cpu_v7m_reset
	globl_equ cpu_cm7_do_idle, cpu_v7m_do_idle
	globl_equ cpu_cm7_switch_mm, cpu_v7m_switch_mm

	define_processor_functions v7m, dabort=nommu_early_abort, pabort=legacy_pabort, nommu=1
	define_processor_functions cm7, 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

	.macro __v7m_proc name, initfunc, cache_fns = nop_cache_fns, hwcaps = 0, proc_fns = v7m_processor_functions
	.long 0 /* proc_info_list.__cpu_mm_mmu_flags */
	.long 0 /* proc_info_list.__cpu_io_mmu_flags */
	initfn \initfunc, \name
	.long cpu_arch_name
	.long cpu_elf_name
	.long HWCAP_HALF \| HWCAP_THUMB \| HWCAP_FAST_MULT \| \hwcaps
	.long cpu_v7m_name
	.long \proc_fns
	.long 0 /* proc_info_list.tlb */
	.long 0 /* proc_info_list.user */
	.long \cache_fns
	.endm

	/*
	* Match ARM Cortex-M7 processor.
	*/
	.type __v7m_cm7_proc_info, #object
	__v7m_cm7_proc_info:
	.long 0x410fc270 /* ARM Cortex-M7 0xC27 */
	.long 0xff0ffff0 /* Mask off revision, patch release */
	__v7m_proc __v7m_cm7_proc_info, __v7m_cm7_setup, hwcaps = HWCAP_EDSP, cache_fns = v7m_cache_fns, proc_fns = cm7_processor_functions
	.size __v7m_cm7_proc_info, . - __v7m_cm7_proc_info

	/*
	* Match ARM Cortex-M4 processor.
	*/
	.type __v7m_cm4_proc_info, #object
	__v7m_cm4_proc_info:
	.long 0x410fc240 /* ARM Cortex-M4 0xC24 */
	.long 0xff0ffff0 /* Mask off revision, patch release */
	__v7m_proc __v7m_cm4_proc_info, __v7m_setup, hwcaps = HWCAP_EDSP
	.size __v7m_cm4_proc_info, . - __v7m_cm4_proc_info

	/*
	* Match ARM Cortex-M3 processor.
	*/
	.type __v7m_cm3_proc_info, #object
	__v7m_cm3_proc_info:
	.long 0x410fc230 /* ARM Cortex-M3 0xC23 */
	.long 0xff0ffff0 /* Mask off revision, patch release */
	__v7m_proc __v7m_cm3_proc_info, __v7m_setup
	.size __v7m_cm3_proc_info, . - __v7m_cm3_proc_info

	/*
	* Match any ARMv7-M processor core.
	*/
	.type __v7m_proc_info, #object
	__v7m_proc_info:
	.long 0x000f0000 @ Required ID value
	.long 0x000f0000 @ Mask for ID
	__v7m_proc __v7m_proc_info, __v7m_setup
	.size __v7m_proc_info, . - __v7m_proc_info