1/* 2 * ARC CPU startup Code 3 * 4 * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com) 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License version 2 as 8 * published by the Free Software Foundation. 9 * 10 * Vineetg: Dec 2007 11 * -Check if we are running on Simulator or on real hardware 12 * to skip certain things during boot on simulator 13 */ 14 15#include <asm/asm-offsets.h> 16#include <asm/entry.h> 17#include <linux/linkage.h> 18#include <asm/arcregs.h> 19 20 .cpu A7 21 22 .section .init.text, "ax",@progbits 23 .type stext, @function 24 .globl stext 25stext: 26 ;------------------------------------------------------------------- 27 ; Don't clobber r0-r4 yet. It might have bootloader provided info 28 ;------------------------------------------------------------------- 29 30 sr @_int_vec_base_lds, [AUX_INTR_VEC_BASE] 31 32#ifdef CONFIG_SMP 33 ; Only Boot (Master) proceeds. Others wait in platform dependent way 34 ; IDENTITY Reg [ 3 2 1 0 ] 35 ; (cpu-id) ^^^ => Zero for UP ARC700 36 ; => #Core-ID if SMP (Master 0) 37 ; Note that non-boot CPUs might not land here if halt-on-reset and 38 ; instead breath life from @first_lines_of_secondary, but we still 39 ; need to make sure only boot cpu takes this path. 40 GET_CPU_ID r5 41 cmp r5, 0 42 jnz arc_platform_smp_wait_to_boot 43#endif 44 ; Clear BSS before updating any globals 45 ; XXX: use ZOL here 46 mov r5, __bss_start 47 mov r6, __bss_stop 481: 49 st.ab 0, [r5,4] 50 brlt r5, r6, 1b 51 52 ; Uboot - kernel ABI 53 ; r0 = [0] No uboot interaction, [1] cmdline in r2, [2] DTB in r2 54 ; r1 = magic number (board identity, unused as of now 55 ; r2 = pointer to uboot provided cmdline or external DTB in mem 56 ; These are handled later in setup_arch() 57 st r0, [@uboot_tag] 58 st r2, [@uboot_arg] 59 60 ; Identify if running on ISS vs Silicon 61 ; IDENTITY Reg [ 3 2 1 0 ] 62 ; (chip-id) ^^^^^ ==> 0xffff for ISS 63 lr r0, [identity] 64 lsr r3, r0, 16 65 cmp r3, 0xffff 66 mov.z r4, 0 67 mov.nz r4, 1 68 st r4, [@running_on_hw] 69 70 ; setup "current" tsk and optionally cache it in dedicated r25 71 mov r9, @init_task 72 SET_CURR_TASK_ON_CPU r9, r0 ; r9 = tsk, r0 = scratch 73 74 ; setup stack (fp, sp) 75 mov fp, 0 76 77 ; tsk->thread_info is really a PAGE, whose bottom hoists stack 78 GET_TSK_STACK_BASE r9, sp ; r9 = tsk, sp = stack base(output) 79 80 j start_kernel ; "C" entry point 81 82#ifdef CONFIG_SMP 83;---------------------------------------------------------------- 84; First lines of code run by secondary before jumping to 'C' 85;---------------------------------------------------------------- 86 .section .text, "ax",@progbits 87 .type first_lines_of_secondary, @function 88 .globl first_lines_of_secondary 89 90first_lines_of_secondary: 91 92 sr @_int_vec_base_lds, [AUX_INTR_VEC_BASE] 93 94 ; setup per-cpu idle task as "current" on this CPU 95 ld r0, [@secondary_idle_tsk] 96 SET_CURR_TASK_ON_CPU r0, r1 97 98 ; setup stack (fp, sp) 99 mov fp, 0 100 101 ; set it's stack base to tsk->thread_info bottom 102 GET_TSK_STACK_BASE r0, sp 103 104 j start_kernel_secondary 105 106#endif 107