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 <linux/linkage.h> 16#include <asm/asm-offsets.h> 17#include <asm/entry.h> 18#include <asm/arcregs.h> 19#include <asm/cache.h> 20 21.macro CPU_EARLY_SETUP 22 23 ; Setting up Vectror Table (in case exception happens in early boot 24 sr @_int_vec_base_lds, [AUX_INTR_VEC_BASE] 25 26 ; Disable I-cache/D-cache if kernel so configured 27 lr r5, [ARC_REG_IC_BCR] 28 breq r5, 0, 1f ; I$ doesn't exist 29 lr r5, [ARC_REG_IC_CTRL] 30#ifdef CONFIG_ARC_HAS_ICACHE 31 bclr r5, r5, 0 ; 0 - Enable, 1 is Disable 32#else 33 bset r5, r5, 0 ; I$ exists, but is not used 34#endif 35 sr r5, [ARC_REG_IC_CTRL] 36 371: 38 lr r5, [ARC_REG_DC_BCR] 39 breq r5, 0, 1f ; D$ doesn't exist 40 lr r5, [ARC_REG_DC_CTRL] 41 bclr r5, r5, 6 ; Invalidate (discard w/o wback) 42#ifdef CONFIG_ARC_HAS_DCACHE 43 bclr r5, r5, 0 ; Enable (+Inv) 44#else 45 bset r5, r5, 0 ; Disable (+Inv) 46#endif 47 sr r5, [ARC_REG_DC_CTRL] 48 491: 50.endm 51 52 .section .init.text, "ax",@progbits 53 54;---------------------------------------------------------------- 55; Default Reset Handler (jumped into from Reset vector) 56; - Don't clobber r0,r1,r2 as they might have u-boot provided args 57; - Platforms can override this weak version if needed 58;---------------------------------------------------------------- 59WEAK(res_service) 60 j stext 61END(res_service) 62 63;---------------------------------------------------------------- 64; Kernel Entry point 65;---------------------------------------------------------------- 66ENTRY(stext) 67 68 CPU_EARLY_SETUP 69 70#ifdef CONFIG_SMP 71 GET_CPU_ID r5 72 cmp r5, 0 73 mov.nz r0, r5 74#ifdef CONFIG_ARC_SMP_HALT_ON_RESET 75 ; Non-Master can proceed as system would be booted sufficiently 76 jnz first_lines_of_secondary 77#else 78 ; Non-Masters wait for Master to boot enough and bring them up 79 jnz arc_platform_smp_wait_to_boot 80#endif 81 ; Master falls thru 82#endif 83 84 ; Clear BSS before updating any globals 85 ; XXX: use ZOL here 86 mov r5, __bss_start 87 sub r6, __bss_stop, r5 88 lsr.f lp_count, r6, 2 89 lpnz 1f 90 st.ab 0, [r5, 4] 911: 92 93#ifdef CONFIG_ARC_UBOOT_SUPPORT 94 ; Uboot - kernel ABI 95 ; r0 = [0] No uboot interaction, [1] cmdline in r2, [2] DTB in r2 96 ; r1 = magic number (board identity, unused as of now 97 ; r2 = pointer to uboot provided cmdline or external DTB in mem 98 ; These are handled later in setup_arch() 99 st r0, [@uboot_tag] 100 st r2, [@uboot_arg] 101#endif 102 103 ; setup "current" tsk and optionally cache it in dedicated r25 104 mov r9, @init_task 105 SET_CURR_TASK_ON_CPU r9, r0 ; r9 = tsk, r0 = scratch 106 107 ; setup stack (fp, sp) 108 mov fp, 0 109 110 ; tsk->thread_info is really a PAGE, whose bottom hoists stack 111 GET_TSK_STACK_BASE r9, sp ; r9 = tsk, sp = stack base(output) 112 113 j start_kernel ; "C" entry point 114END(stext) 115 116#ifdef CONFIG_SMP 117;---------------------------------------------------------------- 118; First lines of code run by secondary before jumping to 'C' 119;---------------------------------------------------------------- 120 .section .text, "ax",@progbits 121ENTRY(first_lines_of_secondary) 122 123 ; setup per-cpu idle task as "current" on this CPU 124 ld r0, [@secondary_idle_tsk] 125 SET_CURR_TASK_ON_CPU r0, r1 126 127 ; setup stack (fp, sp) 128 mov fp, 0 129 130 ; set it's stack base to tsk->thread_info bottom 131 GET_TSK_STACK_BASE r0, sp 132 133 j start_kernel_secondary 134END(first_lines_of_secondary) 135#endif 136