/* * linux/arch/arm/mach-axxia/platsmp.c * * Copyright (C) 2012 LSI Corporation * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. */ #include <linux/init.h> #include <linux/io.h> #include <linux/smp.h> #include <linux/of.h> #include <linux/of_address.h> #include <asm/cacheflush.h> /* Syscon register offsets for releasing cores from reset */ #define SC_CRIT_WRITE_KEY 0x1000 #define SC_RST_CPU_HOLD 0x1010 /* * Write the kernel entry point for secondary CPUs to the specified address */ static void write_release_addr(u32 release_phys) { u32 *virt = (u32 *) phys_to_virt(release_phys); writel_relaxed(__pa_symbol(secondary_startup), virt); /* Make sure this store is visible to other CPUs */ smp_wmb(); __cpuc_flush_dcache_area(virt, sizeof(u32)); } static int axxia_boot_secondary(unsigned int cpu, struct task_struct *idle) { struct device_node *syscon_np; void __iomem *syscon; u32 tmp; syscon_np = of_find_compatible_node(NULL, NULL, "lsi,axxia-syscon"); if (!syscon_np) return -ENOENT; syscon = of_iomap(syscon_np, 0); if (!syscon) return -ENOMEM; tmp = readl(syscon + SC_RST_CPU_HOLD); writel(0xab, syscon + SC_CRIT_WRITE_KEY); tmp &= ~(1 << cpu); writel(tmp, syscon + SC_RST_CPU_HOLD); return 0; } static void __init axxia_smp_prepare_cpus(unsigned int max_cpus) { int cpu_count = 0; int cpu; /* * Initialise the present map, which describes the set of CPUs actually * populated at the present time. */ for_each_possible_cpu(cpu) { struct device_node *np; u32 release_phys; np = of_get_cpu_node(cpu, NULL); if (!np) continue; if (of_property_read_u32(np, "cpu-release-addr", &release_phys)) continue; if (cpu_count < max_cpus) { set_cpu_present(cpu, true); cpu_count++; } if (release_phys != 0) write_release_addr(release_phys); } } static const struct smp_operations axxia_smp_ops __initconst = { .smp_prepare_cpus = axxia_smp_prepare_cpus, .smp_boot_secondary = axxia_boot_secondary, }; CPU_METHOD_OF_DECLARE(axxia_smp, "lsi,syscon-release", &axxia_smp_ops);