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#ifdef CONFIG_SMP 31 ; Only Boot (Master) proceeds. Others wait in platform dependent way 32 ; IDENTITY Reg [ 3 2 1 0 ] 33 ; (cpu-id) ^^^ => Zero for UP ARC700 34 ; => #Core-ID if SMP (Master 0) 35 GET_CPU_ID r5 36 cmp r5, 0 37 jnz arc_platform_smp_wait_to_boot 38#endif 39 ; Clear BSS before updating any globals 40 ; XXX: use ZOL here 41 mov r5, __bss_start 42 mov r6, __bss_stop 431: 44 st.ab 0, [r5,4] 45 brlt r5, r6, 1b 46 47#ifdef CONFIG_CMDLINE_UBOOT 48 ; support for bootloader provided cmdline 49 ; If cmdline passed by u-boot, then 50 ; r0 = 1 (because ATAGS parsing, now retired, used to use 0) 51 ; r1 = magic number (board identity) 52 ; r2 = addr of cmdline string (somewhere in memory/flash) 53 54 brne r0, 1, .Lother_bootup_chores ; u-boot didn't pass cmdline 55 breq r2, 0, .Lother_bootup_chores ; or cmdline is NULL 56 57 mov r5, @command_line 581: 59 ldb.ab r6, [r2, 1] 60 breq r6, 0, .Lother_bootup_chores 61 b.d 1b 62 stb.ab r6, [r5, 1] 63#endif 64 65.Lother_bootup_chores: 66 67 ; Identify if running on ISS vs Silicon 68 ; IDENTITY Reg [ 3 2 1 0 ] 69 ; (chip-id) ^^^^^ ==> 0xffff for ISS 70 lr r0, [identity] 71 lsr r3, r0, 16 72 cmp r3, 0xffff 73 mov.z r4, 0 74 mov.nz r4, 1 75 st r4, [@running_on_hw] 76 77 ; setup "current" tsk and optionally cache it in dedicated r25 78 mov r9, @init_task 79 SET_CURR_TASK_ON_CPU r9, r0 ; r9 = tsk, r0 = scratch 80 81 ; setup stack (fp, sp) 82 mov fp, 0 83 84 ; tsk->thread_info is really a PAGE, whose bottom hoists stack 85 GET_TSK_STACK_BASE r9, sp ; r9 = tsk, sp = stack base(output) 86 87 j start_kernel ; "C" entry point 88 89#ifdef CONFIG_SMP 90;---------------------------------------------------------------- 91; First lines of code run by secondary before jumping to 'C' 92;---------------------------------------------------------------- 93 .section .init.text, "ax",@progbits 94 .type first_lines_of_secondary, @function 95 .globl first_lines_of_secondary 96 97first_lines_of_secondary: 98 99 ; setup per-cpu idle task as "current" on this CPU 100 ld r0, [@secondary_idle_tsk] 101 SET_CURR_TASK_ON_CPU r0, r1 102 103 ; setup stack (fp, sp) 104 mov fp, 0 105 106 ; set it's stack base to tsk->thread_info bottom 107 GET_TSK_STACK_BASE r0, sp 108 109 j start_kernel_secondary 110 111#endif 112