1 /* 2 * OMAP4 SMP source file. It contains platform specific fucntions 3 * needed for the linux smp kernel. 4 * 5 * Copyright (C) 2009 Texas Instruments, Inc. 6 * 7 * Author: 8 * Santosh Shilimkar <santosh.shilimkar@ti.com> 9 * 10 * Platform file needed for the OMAP4 SMP. This file is based on arm 11 * realview smp platform. 12 * * Copyright (c) 2002 ARM Limited. 13 * 14 * This program is free software; you can redistribute it and/or modify 15 * it under the terms of the GNU General Public License version 2 as 16 * published by the Free Software Foundation. 17 */ 18 #include <linux/init.h> 19 #include <linux/device.h> 20 #include <linux/smp.h> 21 #include <linux/io.h> 22 23 #include <asm/cacheflush.h> 24 #include <asm/localtimer.h> 25 #include <asm/smp_scu.h> 26 #include <mach/hardware.h> 27 #include <plat/common.h> 28 29 /* SCU base address */ 30 static void __iomem *scu_base; 31 32 /* 33 * Use SCU config register to count number of cores 34 */ 35 static inline unsigned int get_core_count(void) 36 { 37 if (scu_base) 38 return scu_get_core_count(scu_base); 39 return 1; 40 } 41 42 static DEFINE_SPINLOCK(boot_lock); 43 44 void __cpuinit platform_secondary_init(unsigned int cpu) 45 { 46 trace_hardirqs_off(); 47 48 /* 49 * If any interrupts are already enabled for the primary 50 * core (e.g. timer irq), then they will not have been enabled 51 * for us: do so 52 */ 53 gic_cpu_init(0, gic_cpu_base_addr); 54 55 /* 56 * Synchronise with the boot thread. 57 */ 58 spin_lock(&boot_lock); 59 spin_unlock(&boot_lock); 60 } 61 62 int __cpuinit boot_secondary(unsigned int cpu, struct task_struct *idle) 63 { 64 /* 65 * Set synchronisation state between this boot processor 66 * and the secondary one 67 */ 68 spin_lock(&boot_lock); 69 70 /* 71 * Update the AuxCoreBoot0 with boot state for secondary core. 72 * omap_secondary_startup() routine will hold the secondary core till 73 * the AuxCoreBoot1 register is updated with cpu state 74 * A barrier is added to ensure that write buffer is drained 75 */ 76 omap_modify_auxcoreboot0(0x200, 0x0); 77 flush_cache_all(); 78 smp_wmb(); 79 80 /* 81 * Now the secondary core is starting up let it run its 82 * calibrations, then wait for it to finish 83 */ 84 spin_unlock(&boot_lock); 85 86 return 0; 87 } 88 89 static void __init wakeup_secondary(void) 90 { 91 /* 92 * Write the address of secondary startup routine into the 93 * AuxCoreBoot1 where ROM code will jump and start executing 94 * on secondary core once out of WFE 95 * A barrier is added to ensure that write buffer is drained 96 */ 97 omap_auxcoreboot_addr(virt_to_phys(omap_secondary_startup)); 98 smp_wmb(); 99 100 /* 101 * Send a 'sev' to wake the secondary core from WFE. 102 * Drain the outstanding writes to memory 103 */ 104 dsb(); 105 set_event(); 106 mb(); 107 } 108 109 /* 110 * Initialise the CPU possible map early - this describes the CPUs 111 * which may be present or become present in the system. 112 */ 113 void __init smp_init_cpus(void) 114 { 115 unsigned int i, ncores; 116 117 /* Never released */ 118 scu_base = ioremap(OMAP44XX_SCU_BASE, SZ_256); 119 BUG_ON(!scu_base); 120 121 ncores = get_core_count(); 122 123 for (i = 0; i < ncores; i++) 124 set_cpu_possible(i, true); 125 } 126 127 void __init smp_prepare_cpus(unsigned int max_cpus) 128 { 129 unsigned int ncores = get_core_count(); 130 unsigned int cpu = smp_processor_id(); 131 int i; 132 133 /* sanity check */ 134 if (ncores == 0) { 135 printk(KERN_ERR 136 "OMAP4: strange core count of 0? Default to 1\n"); 137 ncores = 1; 138 } 139 140 if (ncores > NR_CPUS) { 141 printk(KERN_WARNING 142 "OMAP4: no. of cores (%d) greater than configured " 143 "maximum of %d - clipping\n", 144 ncores, NR_CPUS); 145 ncores = NR_CPUS; 146 } 147 smp_store_cpu_info(cpu); 148 149 /* 150 * are we trying to boot more cores than exist? 151 */ 152 if (max_cpus > ncores) 153 max_cpus = ncores; 154 155 /* 156 * Initialise the present map, which describes the set of CPUs 157 * actually populated at the present time. 158 */ 159 for (i = 0; i < max_cpus; i++) 160 set_cpu_present(i, true); 161 162 if (max_cpus > 1) { 163 /* 164 * Enable the local timer or broadcast device for the 165 * boot CPU, but only if we have more than one CPU. 166 */ 167 percpu_timer_setup(); 168 169 /* 170 * Initialise the SCU and wake up the secondary core using 171 * wakeup_secondary(). 172 */ 173 scu_enable(scu_base); 174 wakeup_secondary(); 175 } 176 } 177