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/*
* 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);
of_node_put(syscon_np);
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);
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