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torvalds
GitHub Repository: torvalds/linux
 Path: blob/master/arch/arm/mach-mvebu/platsmp-a9.c
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// SPDX-License-Identifier: GPL-2.0-only

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/*

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 * Symmetric Multi Processing (SMP) support for Marvell EBU Cortex-A9

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 * based SOCs (Armada 375/38x).

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 *

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 * Copyright (C) 2014 Marvell

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 *

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 * Gregory CLEMENT <[email protected]>

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 * Thomas Petazzoni <[email protected]>

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 */

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#include <linux/init.h>

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#include <linux/io.h>

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#include <linux/of.h>

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#include <linux/smp.h>

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#include <linux/mbus.h>

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#include <asm/smp_scu.h>

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#include <asm/smp_plat.h>

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#include "common.h"

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#include "pmsu.h"

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extern void mvebu_cortex_a9_secondary_startup(void);

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static int mvebu_cortex_a9_boot_secondary(unsigned int cpu,

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						    struct task_struct *idle)

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{

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	int ret, hw_cpu;

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	pr_info("Booting CPU %d\n", cpu);

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	/*

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	 * Write the address of secondary startup into the system-wide

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	 * flags register. The boot monitor waits until it receives a

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	 * soft interrupt, and then the secondary CPU branches to this

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	 * address.

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	 */

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	hw_cpu = cpu_logical_map(cpu);

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	if (of_machine_is_compatible("marvell,armada375"))

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		mvebu_system_controller_set_cpu_boot_addr(mvebu_cortex_a9_secondary_startup);

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	else

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		mvebu_pmsu_set_cpu_boot_addr(hw_cpu, mvebu_cortex_a9_secondary_startup);

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	smp_wmb();

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	/*

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	 * Doing this before deasserting the CPUs is needed to wake up CPUs

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	 * in the offline state after using CPU hotplug.

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	 */

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	arch_send_wakeup_ipi_mask(cpumask_of(cpu));

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	ret = mvebu_cpu_reset_deassert(hw_cpu);

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	if (ret) {

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		pr_err("Could not start the secondary CPU: %d\n", ret);

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		return ret;

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	}

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	return 0;

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}

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/*

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 * When a CPU is brought back online, either through CPU hotplug, or

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 * because of the boot of a kexec'ed kernel, the PMSU configuration

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 * for this CPU might be in the deep idle state, preventing this CPU

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 * from receiving interrupts. Here, we therefore take out the current

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 * CPU from this state, which was entered by armada_38x_cpu_die()

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 * below.

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 */

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static void armada_38x_secondary_init(unsigned int cpu)

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{

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	mvebu_v7_pmsu_idle_exit();

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}

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#ifdef CONFIG_HOTPLUG_CPU

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static void armada_38x_cpu_die(unsigned int cpu)

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{

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	/*

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	 * CPU hotplug is implemented by putting offline CPUs into the

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	 * deep idle sleep state.

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	 */

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	armada_38x_do_cpu_suspend(true);

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}

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/*

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 * We need a dummy function, so that platform_can_cpu_hotplug() knows

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 * we support CPU hotplug. However, the function does not need to do

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 * anything, because CPUs going offline can enter the deep idle state

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 * by themselves, without any help from a still alive CPU.

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 */

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static int armada_38x_cpu_kill(unsigned int cpu)

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{

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	return 1;

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}

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#endif

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static const struct smp_operations mvebu_cortex_a9_smp_ops __initconst = {

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	.smp_boot_secondary	= mvebu_cortex_a9_boot_secondary,

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};

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static const struct smp_operations armada_38x_smp_ops __initconst = {

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	.smp_boot_secondary	= mvebu_cortex_a9_boot_secondary,

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	.smp_secondary_init     = armada_38x_secondary_init,

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#ifdef CONFIG_HOTPLUG_CPU

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	.cpu_die		= armada_38x_cpu_die,

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	.cpu_kill               = armada_38x_cpu_kill,

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#endif

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};

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CPU_METHOD_OF_DECLARE(mvebu_armada_375_smp, "marvell,armada-375-smp",

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		      &mvebu_cortex_a9_smp_ops);

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CPU_METHOD_OF_DECLARE(mvebu_armada_380_smp, "marvell,armada-380-smp",

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		      &armada_38x_smp_ops);

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CPU_METHOD_OF_DECLARE(mvebu_armada_390_smp, "marvell,armada-390-smp",

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		      &armada_38x_smp_ops);

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