linux/arch/arm/mach-mvebu/platsmp-a9.c

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/*
* Symmetric Multi Processing (SMP) support for Marvell EBU Cortex-A9
* based SOCs (Armada 375/38x).
*
* Copyright (C) 2014 Marvell
*
* Gregory CLEMENT <gregory.clement@free-electrons.com>
* Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
*
* This file is licensed under the terms of the GNU General Public
* License version 2. This program is licensed "as is" without any
* warranty of any kind, whether express or implied.
*/
#include <linux/init.h>
#include <linux/io.h>
#include <linux/of.h>
#include <linux/smp.h>
#include <linux/mbus.h>
#include <asm/smp_scu.h>
#include <asm/smp_plat.h>
#include "common.h"
#include "pmsu.h"
extern void mvebu_cortex_a9_secondary_startup(void);
static int __cpuinit mvebu_cortex_a9_boot_secondary(unsigned int cpu,
struct task_struct *idle)
{
int ret, hw_cpu;
pr_info("Booting CPU %d\n", cpu);
/*
* Write the address of secondary startup into the system-wide
* flags register. The boot monitor waits until it receives a
* soft interrupt, and then the secondary CPU branches to this
* address.
*/
hw_cpu = cpu_logical_map(cpu);
if (of_machine_is_compatible("marvell,armada375"))
mvebu_system_controller_set_cpu_boot_addr(mvebu_cortex_a9_secondary_startup);
else
mvebu_pmsu_set_cpu_boot_addr(hw_cpu, mvebu_cortex_a9_secondary_startup);
smp_wmb();
/*
* Doing this before deasserting the CPUs is needed to wake up CPUs
* in the offline state after using CPU hotplug.
*/
arch_send_wakeup_ipi_mask(cpumask_of(cpu));
ret = mvebu_cpu_reset_deassert(hw_cpu);
if (ret) {
pr_err("Could not start the secondary CPU: %d\n", ret);
return ret;
}
return 0;
}
/*
* When a CPU is brought back online, either through CPU hotplug, or
* because of the boot of a kexec'ed kernel, the PMSU configuration
* for this CPU might be in the deep idle state, preventing this CPU
* from receiving interrupts. Here, we therefore take out the current
* CPU from this state, which was entered by armada_38x_cpu_die()
* below.
*/
static void armada_38x_secondary_init(unsigned int cpu)
{
mvebu_v7_pmsu_idle_exit();
}
#ifdef CONFIG_HOTPLUG_CPU
static void armada_38x_cpu_die(unsigned int cpu)
{
/*
* CPU hotplug is implemented by putting offline CPUs into the
* deep idle sleep state.
*/
armada_38x_do_cpu_suspend(true);
}
/*
* We need a dummy function, so that platform_can_cpu_hotplug() knows
* we support CPU hotplug. However, the function does not need to do
* anything, because CPUs going offline can enter the deep idle state
* by themselves, without any help from a still alive CPU.
*/
static int armada_38x_cpu_kill(unsigned int cpu)
{
return 1;
}
#endif
static struct smp_operations mvebu_cortex_a9_smp_ops __initdata = {
.smp_boot_secondary = mvebu_cortex_a9_boot_secondary,
};
static struct smp_operations armada_38x_smp_ops __initdata = {
.smp_boot_secondary = mvebu_cortex_a9_boot_secondary,
.smp_secondary_init = armada_38x_secondary_init,
#ifdef CONFIG_HOTPLUG_CPU
.cpu_die = armada_38x_cpu_die,
.cpu_kill = armada_38x_cpu_kill,
#endif
};
CPU_METHOD_OF_DECLARE(mvebu_armada_375_smp, "marvell,armada-375-smp",
&mvebu_cortex_a9_smp_ops);
CPU_METHOD_OF_DECLARE(mvebu_armada_380_smp, "marvell,armada-380-smp",
&armada_38x_smp_ops);
CPU_METHOD_OF_DECLARE(mvebu_armada_390_smp, "marvell,armada-390-smp",
&armada_38x_smp_ops);