1 /* 2 * linux/arch/arm/mach-axxia/platsmp.c 3 * 4 * Copyright (C) 2012 LSI Corporation 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 11 #include <linux/init.h> 12 #include <linux/io.h> 13 #include <linux/smp.h> 14 #include <linux/of.h> 15 #include <linux/of_address.h> 16 #include <asm/cacheflush.h> 17 18 /* Syscon register offsets for releasing cores from reset */ 19 #define SC_CRIT_WRITE_KEY 0x1000 20 #define SC_RST_CPU_HOLD 0x1010 21 22 /* 23 * Write the kernel entry point for secondary CPUs to the specified address 24 */ 25 static void write_release_addr(u32 release_phys) 26 { 27 u32 *virt = (u32 *) phys_to_virt(release_phys); 28 writel_relaxed(virt_to_phys(secondary_startup), virt); 29 /* Make sure this store is visible to other CPUs */ 30 smp_wmb(); 31 __cpuc_flush_dcache_area(virt, sizeof(u32)); 32 } 33 34 static int axxia_boot_secondary(unsigned int cpu, struct task_struct *idle) 35 { 36 struct device_node *syscon_np; 37 void __iomem *syscon; 38 u32 tmp; 39 40 syscon_np = of_find_compatible_node(NULL, NULL, "lsi,axxia-syscon"); 41 if (!syscon_np) 42 return -ENOENT; 43 44 syscon = of_iomap(syscon_np, 0); 45 if (!syscon) 46 return -ENOMEM; 47 48 tmp = readl(syscon + SC_RST_CPU_HOLD); 49 writel(0xab, syscon + SC_CRIT_WRITE_KEY); 50 tmp &= ~(1 << cpu); 51 writel(tmp, syscon + SC_RST_CPU_HOLD); 52 53 return 0; 54 } 55 56 static void __init axxia_smp_prepare_cpus(unsigned int max_cpus) 57 { 58 int cpu_count = 0; 59 int cpu; 60 61 /* 62 * Initialise the present map, which describes the set of CPUs actually 63 * populated at the present time. 64 */ 65 for_each_possible_cpu(cpu) { 66 struct device_node *np; 67 u32 release_phys; 68 69 np = of_get_cpu_node(cpu, NULL); 70 if (!np) 71 continue; 72 if (of_property_read_u32(np, "cpu-release-addr", &release_phys)) 73 continue; 74 75 if (cpu_count < max_cpus) { 76 set_cpu_present(cpu, true); 77 cpu_count++; 78 } 79 80 if (release_phys != 0) 81 write_release_addr(release_phys); 82 } 83 } 84 85 static const struct smp_operations axxia_smp_ops __initconst = { 86 .smp_prepare_cpus = axxia_smp_prepare_cpus, 87 .smp_boot_secondary = axxia_boot_secondary, 88 }; 89 CPU_METHOD_OF_DECLARE(axxia_smp, "lsi,syscon-release", &axxia_smp_ops); 90