1*c121c506SVineet Gupta/* 2*c121c506SVineet Gupta * ARC CPU startup Code 3*c121c506SVineet Gupta * 4*c121c506SVineet Gupta * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com) 5*c121c506SVineet Gupta * 6*c121c506SVineet Gupta * This program is free software; you can redistribute it and/or modify 7*c121c506SVineet Gupta * it under the terms of the GNU General Public License version 2 as 8*c121c506SVineet Gupta * published by the Free Software Foundation. 9*c121c506SVineet Gupta * 10*c121c506SVineet Gupta * Vineetg: Dec 2007 11*c121c506SVineet Gupta * -Check if we are running on Simulator or on real hardware 12*c121c506SVineet Gupta * to skip certain things during boot on simulator 13*c121c506SVineet Gupta */ 14*c121c506SVineet Gupta 15*c121c506SVineet Gupta#include <asm/asm-offsets.h> 16*c121c506SVineet Gupta#include <asm/entry.h> 17*c121c506SVineet Gupta#include <linux/linkage.h> 18*c121c506SVineet Gupta#include <asm/arcregs.h> 19*c121c506SVineet Gupta 20*c121c506SVineet Gupta .cpu A7 21*c121c506SVineet Gupta 22*c121c506SVineet Gupta .section .init.text, "ax",@progbits 23*c121c506SVineet Gupta .type stext, @function 24*c121c506SVineet Gupta .globl stext 25*c121c506SVineet Guptastext: 26*c121c506SVineet Gupta ;------------------------------------------------------------------- 27*c121c506SVineet Gupta ; Don't clobber r0-r4 yet. It might have bootloader provided info 28*c121c506SVineet Gupta ;------------------------------------------------------------------- 29*c121c506SVineet Gupta 30*c121c506SVineet Gupta ; Clear BSS before updating any globals 31*c121c506SVineet Gupta ; XXX: use ZOL here 32*c121c506SVineet Gupta mov r5, __bss_start 33*c121c506SVineet Gupta mov r6, __bss_stop 34*c121c506SVineet Gupta1: 35*c121c506SVineet Gupta st.ab 0, [r5,4] 36*c121c506SVineet Gupta brlt r5, r6, 1b 37*c121c506SVineet Gupta 38*c121c506SVineet Gupta#ifdef CONFIG_CMDLINE_UBOOT 39*c121c506SVineet Gupta ; support for bootloader provided cmdline 40*c121c506SVineet Gupta ; If cmdline passed by u-boot, then 41*c121c506SVineet Gupta ; r0 = 1 (because ATAGS parsing, now retired, used to use 0) 42*c121c506SVineet Gupta ; r1 = magic number (board identity) 43*c121c506SVineet Gupta ; r2 = addr of cmdline string (somewhere in memory/flash) 44*c121c506SVineet Gupta 45*c121c506SVineet Gupta brne r0, 1, .Lother_bootup_chores ; u-boot didn't pass cmdline 46*c121c506SVineet Gupta breq r2, 0, .Lother_bootup_chores ; or cmdline is NULL 47*c121c506SVineet Gupta 48*c121c506SVineet Gupta mov r5, @command_line 49*c121c506SVineet Gupta1: 50*c121c506SVineet Gupta ldb.ab r6, [r2, 1] 51*c121c506SVineet Gupta breq r6, 0, .Lother_bootup_chores 52*c121c506SVineet Gupta b.d 1b 53*c121c506SVineet Gupta stb.ab r6, [r5, 1] 54*c121c506SVineet Gupta#endif 55*c121c506SVineet Gupta 56*c121c506SVineet Gupta.Lother_bootup_chores: 57*c121c506SVineet Gupta 58*c121c506SVineet Gupta ; Identify if running on ISS vs Silicon 59*c121c506SVineet Gupta ; IDENTITY Reg [ 3 2 1 0 ] 60*c121c506SVineet Gupta ; (chip-id) ^^^^^ ==> 0xffff for ISS 61*c121c506SVineet Gupta lr r0, [identity] 62*c121c506SVineet Gupta lsr r3, r0, 16 63*c121c506SVineet Gupta cmp r3, 0xffff 64*c121c506SVineet Gupta mov.z r4, 0 65*c121c506SVineet Gupta mov.nz r4, 1 66*c121c506SVineet Gupta st r4, [@running_on_hw] 67*c121c506SVineet Gupta 68*c121c506SVineet Gupta ; setup "current" tsk and optionally cache it in dedicated r25 69*c121c506SVineet Gupta mov r9, @init_task 70*c121c506SVineet Gupta SET_CURR_TASK_ON_CPU r9, r0 ; r9 = tsk, r0 = scratch 71*c121c506SVineet Gupta 72*c121c506SVineet Gupta ; setup stack (fp, sp) 73*c121c506SVineet Gupta mov fp, 0 74*c121c506SVineet Gupta 75*c121c506SVineet Gupta ; tsk->thread_info is really a PAGE, whose bottom hoists stack 76*c121c506SVineet Gupta GET_TSK_STACK_BASE r9, sp ; r9 = tsk, sp = stack base(output) 77*c121c506SVineet Gupta 78*c121c506SVineet Gupta j start_kernel ; "C" entry point 79