1 /* 2 * arch/arm/mach-sti/platsmp.c 3 * 4 * Copyright (C) 2013 STMicroelectronics (R&D) Limited. 5 * http://www.st.com 6 * 7 * Cloned from linux/arch/arm/mach-vexpress/platsmp.c 8 * 9 * Copyright (C) 2002 ARM Ltd. 10 * All Rights Reserved 11 * 12 * This program is free software; you can redistribute it and/or modify 13 * it under the terms of the GNU General Public License version 2 as 14 * published by the Free Software Foundation. 15 */ 16 #include <linux/init.h> 17 #include <linux/errno.h> 18 #include <linux/delay.h> 19 #include <linux/smp.h> 20 #include <linux/io.h> 21 #include <linux/of.h> 22 #include <linux/of_address.h> 23 #include <linux/memblock.h> 24 25 #include <asm/cacheflush.h> 26 #include <asm/smp_plat.h> 27 #include <asm/smp_scu.h> 28 29 #include "smp.h" 30 31 static u32 __iomem *cpu_strt_ptr; 32 33 static int sti_boot_secondary(unsigned int cpu, struct task_struct *idle) 34 { 35 unsigned long entry_pa = __pa_symbol(secondary_startup); 36 37 /* 38 * Secondary CPU is initialised and started by a U-BOOTROM firmware. 39 * Secondary CPU is spinning and waiting for a write at cpu_strt_ptr. 40 * Writing secondary_startup address at cpu_strt_ptr makes it to 41 * jump directly to secondary_startup(). 42 */ 43 __raw_writel(entry_pa, cpu_strt_ptr); 44 45 /* wmb so that data is actually written before cache flush is done */ 46 smp_wmb(); 47 sync_cache_w(cpu_strt_ptr); 48 49 return 0; 50 } 51 52 static void __init sti_smp_prepare_cpus(unsigned int max_cpus) 53 { 54 struct device_node *np; 55 void __iomem *scu_base; 56 u32 release_phys; 57 int cpu; 58 59 np = of_find_compatible_node(NULL, NULL, "arm,cortex-a9-scu"); 60 61 if (np) { 62 scu_base = of_iomap(np, 0); 63 scu_enable(scu_base); 64 of_node_put(np); 65 } 66 67 if (max_cpus <= 1) 68 return; 69 70 for_each_possible_cpu(cpu) { 71 72 np = of_get_cpu_node(cpu, NULL); 73 74 if (!np) 75 continue; 76 77 if (of_property_read_u32(np, "cpu-release-addr", 78 &release_phys)) { 79 pr_err("CPU %d: missing or invalid cpu-release-addr " 80 "property\n", cpu); 81 continue; 82 } 83 84 /* 85 * cpu-release-addr is usually configured in SBC DMEM but can 86 * also be in RAM. 87 */ 88 89 if (!memblock_is_memory(release_phys)) 90 cpu_strt_ptr = 91 ioremap(release_phys, sizeof(release_phys)); 92 else 93 cpu_strt_ptr = 94 (u32 __iomem *)phys_to_virt(release_phys); 95 96 set_cpu_possible(cpu, true); 97 } 98 } 99 100 const struct smp_operations sti_smp_ops __initconst = { 101 .smp_prepare_cpus = sti_smp_prepare_cpus, 102 .smp_boot_secondary = sti_boot_secondary, 103 }; 104