1/* 2 * linux/arch/arm/mach-realview/platsmp.c 3 * 4 * Copyright (C) 2002 ARM Ltd. 5 * All Rights Reserved 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#include <linux/init.h> 12#include <linux/errno.h> 13#include <linux/delay.h> 14#include <linux/device.h> 15#include <linux/jiffies.h> 16#include <linux/smp.h> 17#include <linux/io.h> 18 19#include <asm/cacheflush.h> 20#include <mach/hardware.h> 21#include <asm/mach-types.h> 22#include <asm/localtimer.h> 23#include <asm/unified.h> 24 25#include <mach/board-eb.h> 26#include <mach/board-pb11mp.h> 27#include <mach/board-pbx.h> 28#include <asm/smp_scu.h> 29 30#include "core.h" 31 32extern void realview_secondary_startup(void); 33 34/* 35 * control for which core is the next to come out of the secondary 36 * boot "holding pen" 37 */ 38volatile int __cpuinitdata pen_release = -1; 39 40static void __iomem *scu_base_addr(void) 41{ 42 if (machine_is_realview_eb_mp()) 43 return __io_address(REALVIEW_EB11MP_SCU_BASE); 44 else if (machine_is_realview_pb11mp()) 45 return __io_address(REALVIEW_TC11MP_SCU_BASE); 46 else if (machine_is_realview_pbx() && 47 (core_tile_pbx11mp() || core_tile_pbxa9mp())) 48 return __io_address(REALVIEW_PBX_TILE_SCU_BASE); 49 else 50 return (void __iomem *)0; 51} 52 53static inline unsigned int get_core_count(void) 54{ 55 void __iomem *scu_base = scu_base_addr(); 56 if (scu_base) 57 return scu_get_core_count(scu_base); 58 return 1; 59} 60 61static DEFINE_SPINLOCK(boot_lock); 62 63void __cpuinit platform_secondary_init(unsigned int cpu) 64{ 65 trace_hardirqs_off(); 66 67 /* 68 * if any interrupts are already enabled for the primary 69 * core (e.g. timer irq), then they will not have been enabled 70 * for us: do so 71 */ 72 gic_cpu_init(0, gic_cpu_base_addr); 73 74 /* 75 * let the primary processor know we're out of the 76 * pen, then head off into the C entry point 77 */ 78 pen_release = -1; 79 smp_wmb(); 80 81 /* 82 * Synchronise with the boot thread. 83 */ 84 spin_lock(&boot_lock); 85 spin_unlock(&boot_lock); 86} 87 88int __cpuinit boot_secondary(unsigned int cpu, struct task_struct *idle) 89{ 90 unsigned long timeout; 91 92 /* 93 * set synchronisation state between this boot processor 94 * and the secondary one 95 */ 96 spin_lock(&boot_lock); 97 98 /* 99 * The secondary processor is waiting to be released from 100 * the holding pen - release it, then wait for it to flag 101 * that it has been released by resetting pen_release. 102 * 103 * Note that "pen_release" is the hardware CPU ID, whereas 104 * "cpu" is Linux's internal ID. 105 */ 106 pen_release = cpu; 107 flush_cache_all(); 108 109 smp_cross_call(cpumask_of(cpu)); 110 111 timeout = jiffies + (1 * HZ); 112 while (time_before(jiffies, timeout)) { 113 smp_rmb(); 114 if (pen_release == -1) 115 break; 116 117 udelay(10); 118 } 119 120 /* 121 * now the secondary core is starting up let it run its 122 * calibrations, then wait for it to finish 123 */ 124 spin_unlock(&boot_lock); 125 126 return pen_release != -1 ? -ENOSYS : 0; 127} 128 129static void __init poke_milo(void) 130{ 131 /* nobody is to be released from the pen yet */ 132 pen_release = -1; 133 134 /* 135 * Write the address of secondary startup into the system-wide flags 136 * register. The BootMonitor waits for this register to become 137 * non-zero. 138 */ 139 __raw_writel(BSYM(virt_to_phys(realview_secondary_startup)), 140 __io_address(REALVIEW_SYS_FLAGSSET)); 141 142 mb(); 143} 144 145/* 146 * Initialise the CPU possible map early - this describes the CPUs 147 * which may be present or become present in the system. 148 */ 149void __init smp_init_cpus(void) 150{ 151 unsigned int i, ncores = get_core_count(); 152 153 for (i = 0; i < ncores; i++) 154 set_cpu_possible(i, true); 155} 156 157void __init smp_prepare_cpus(unsigned int max_cpus) 158{ 159 unsigned int ncores = get_core_count(); 160 unsigned int cpu = smp_processor_id(); 161 int i; 162 163 /* sanity check */ 164 if (ncores == 0) { 165 printk(KERN_ERR 166 "Realview: strange CM count of 0? Default to 1\n"); 167 168 ncores = 1; 169 } 170 171 if (ncores > NR_CPUS) { 172 printk(KERN_WARNING 173 "Realview: no. of cores (%d) greater than configured " 174 "maximum of %d - clipping\n", 175 ncores, NR_CPUS); 176 ncores = NR_CPUS; 177 } 178 179 smp_store_cpu_info(cpu); 180 181 /* 182 * are we trying to boot more cores than exist? 183 */ 184 if (max_cpus > ncores) 185 max_cpus = ncores; 186 187 /* 188 * Initialise the present map, which describes the set of CPUs 189 * actually populated at the present time. 190 */ 191 for (i = 0; i < max_cpus; i++) 192 set_cpu_present(i, true); 193 194 /* 195 * Initialise the SCU if there are more than one CPU and let 196 * them know where to start. Note that, on modern versions of 197 * MILO, the "poke" doesn't actually do anything until each 198 * individual core is sent a soft interrupt to get it out of 199 * WFI 200 */ 201 if (max_cpus > 1) { 202 /* 203 * Enable the local timer or broadcast device for the 204 * boot CPU, but only if we have more than one CPU. 205 */ 206 percpu_timer_setup(); 207 208 scu_enable(scu_base_addr()); 209 poke_milo(); 210 } 211} 212