626d686487
This commit implements the CPU hotplug support for the Marvell Armada
38x platform. Similarly to what was done for the Armada XP, this
commit:
* Implements the ->cpu_die() function of SMP operations by calling
armada_38x_do_cpu_suspend() to enter the deep idle state for
CPUs going offline.
* Implements a dummy ->cpu_kill() function, simply needed for the
kernel to know we have CPU hotplug support.
* The mvebu_cortex_a9_boot_secondary() function makes sure to wake up
the CPU if waiting in deep idle state by sending an IPI before
deasserting the CPUs from reset. This is because
mvebu_cortex_a9_boot_secondary() is now used in two different
situations: for the initial boot of secondary CPUs (where CPU reset
deassert is used to wake up CPUs) and for CPU hotplug (where an IPI
is used to take CPU out of deep idle).
* At boot time, we exit from the idle state in the
->smp_secondary_init() hook.
This commit has been tested using CPU hotplug through sysfs
(/sys/devices/system/cpu/cpuX/online) and using kexec.
Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
Tested-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Reviewed-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Link: https://lkml.kernel.org/r/1414669184-16785-5-git-send-email-gregory.clement@free-electrons.com
Signed-off-by: Jason Cooper <jason@lakedaemon.net>
112 lines
3.2 KiB
C
112 lines
3.2 KiB
C
/*
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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 <gregory.clement@free-electrons.com>
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* Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
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*
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* This file is licensed under the terms of the GNU General Public
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* License version 2. This program is licensed "as is" without any
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* warranty of any kind, whether express or implied.
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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 __cpuinit 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 struct smp_operations mvebu_cortex_a9_smp_ops __initdata = {
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.smp_boot_secondary = mvebu_cortex_a9_boot_secondary,
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};
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static struct smp_operations armada_38x_smp_ops __initdata = {
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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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