1/* 2 * linux/arch/arm/mm/proc-v7m.S 3 * 4 * Copyright (C) 2008 ARM Ltd. 5 * Copyright (C) 2001 Deep Blue Solutions Ltd. 6 * 7 * This program is free software; you can redistribute it and/or modify 8 * it under the terms of the GNU General Public License version 2 as 9 * published by the Free Software Foundation. 10 * 11 * This is the "shell" of the ARMv7-M processor support. 12 */ 13#include <linux/linkage.h> 14#include <asm/assembler.h> 15#include <asm/v7m.h> 16#include "proc-macros.S" 17 18ENTRY(cpu_v7m_proc_init) 19 ret lr 20ENDPROC(cpu_v7m_proc_init) 21 22ENTRY(cpu_v7m_proc_fin) 23 ret lr 24ENDPROC(cpu_v7m_proc_fin) 25 26/* 27 * cpu_v7m_reset(loc) 28 * 29 * Perform a soft reset of the system. Put the CPU into the 30 * same state as it would be if it had been reset, and branch 31 * to what would be the reset vector. 32 * 33 * - loc - location to jump to for soft reset 34 */ 35 .align 5 36ENTRY(cpu_v7m_reset) 37 ret r0 38ENDPROC(cpu_v7m_reset) 39 40/* 41 * cpu_v7m_do_idle() 42 * 43 * Idle the processor (eg, wait for interrupt). 44 * 45 * IRQs are already disabled. 46 */ 47ENTRY(cpu_v7m_do_idle) 48 wfi 49 ret lr 50ENDPROC(cpu_v7m_do_idle) 51 52ENTRY(cpu_v7m_dcache_clean_area) 53 ret lr 54ENDPROC(cpu_v7m_dcache_clean_area) 55 56/* 57 * There is no MMU, so here is nothing to do. 58 */ 59ENTRY(cpu_v7m_switch_mm) 60 ret lr 61ENDPROC(cpu_v7m_switch_mm) 62 63.globl cpu_v7m_suspend_size 64.equ cpu_v7m_suspend_size, 0 65 66#ifdef CONFIG_ARM_CPU_SUSPEND 67ENTRY(cpu_v7m_do_suspend) 68 ret lr 69ENDPROC(cpu_v7m_do_suspend) 70 71ENTRY(cpu_v7m_do_resume) 72 ret lr 73ENDPROC(cpu_v7m_do_resume) 74#endif 75 76 .section ".text.init", #alloc, #execinstr 77 78/* 79 * __v7m_setup 80 * 81 * This should be able to cover all ARMv7-M cores. 82 */ 83__v7m_setup: 84 @ Configure the vector table base address 85 ldr r0, =BASEADDR_V7M_SCB 86 ldr r12, =vector_table 87 str r12, [r0, V7M_SCB_VTOR] 88 89 @ enable UsageFault, BusFault and MemManage fault. 90 ldr r5, [r0, #V7M_SCB_SHCSR] 91 orr r5, #(V7M_SCB_SHCSR_USGFAULTENA | V7M_SCB_SHCSR_BUSFAULTENA | V7M_SCB_SHCSR_MEMFAULTENA) 92 str r5, [r0, #V7M_SCB_SHCSR] 93 94 @ Lower the priority of the SVC and PendSV exceptions 95 mov r5, #0x80000000 96 str r5, [r0, V7M_SCB_SHPR2] @ set SVC priority 97 mov r5, #0x00800000 98 str r5, [r0, V7M_SCB_SHPR3] @ set PendSV priority 99 100 @ SVC to run the kernel in this mode 101 badr r1, 1f 102 ldr r5, [r12, #11 * 4] @ read the SVC vector entry 103 str r1, [r12, #11 * 4] @ write the temporary SVC vector entry 104 mov r6, lr @ save LR 105 mov r7, sp @ save SP 106 ldr sp, =__v7m_setup_stack_top 107 cpsie i 108 svc #0 1091: cpsid i 110 str r5, [r12, #11 * 4] @ restore the original SVC vector entry 111 mov lr, r6 @ restore LR 112 mov sp, r7 @ restore SP 113 114 @ Special-purpose control register 115 mov r1, #1 116 msr control, r1 @ Thread mode has unpriviledged access 117 118 @ Configure the System Control Register to ensure 8-byte stack alignment 119 @ Note the STKALIGN bit is either RW or RAO. 120 ldr r12, [r0, V7M_SCB_CCR] @ system control register 121 orr r12, #V7M_SCB_CCR_STKALIGN 122 str r12, [r0, V7M_SCB_CCR] 123 ret lr 124ENDPROC(__v7m_setup) 125 126 .align 2 127__v7m_setup_stack: 128 .space 4 * 8 @ 8 registers 129__v7m_setup_stack_top: 130 131 define_processor_functions v7m, dabort=nommu_early_abort, pabort=legacy_pabort, nommu=1 132 133 .section ".rodata" 134 string cpu_arch_name, "armv7m" 135 string cpu_elf_name "v7m" 136 string cpu_v7m_name "ARMv7-M" 137 138 .section ".proc.info.init", #alloc 139 140 /* 141 * Match any ARMv7-M processor core. 142 */ 143 .type __v7m_proc_info, #object 144__v7m_proc_info: 145 .long 0x000f0000 @ Required ID value 146 .long 0x000f0000 @ Mask for ID 147 .long 0 @ proc_info_list.__cpu_mm_mmu_flags 148 .long 0 @ proc_info_list.__cpu_io_mmu_flags 149 initfn __v7m_setup, __v7m_proc_info @ proc_info_list.__cpu_flush 150 .long cpu_arch_name 151 .long cpu_elf_name 152 .long HWCAP_HALF|HWCAP_THUMB|HWCAP_FAST_MULT 153 .long cpu_v7m_name 154 .long v7m_processor_functions @ proc_info_list.proc 155 .long 0 @ proc_info_list.tlb 156 .long 0 @ proc_info_list.user 157 .long nop_cache_fns @ proc_info_list.cache 158 .size __v7m_proc_info, . - __v7m_proc_info 159 160