1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Symmetric Multi Processing (SMP) support for Marvell EBU Cortex-A9
4 * based SOCs (Armada 375/38x).
5 *
6 * Copyright (C) 2014 Marvell
7 *
8 * Gregory CLEMENT <gregory.clement@free-electrons.com>
9 * Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
10 */
11
12#include <linux/init.h>
13#include <linux/io.h>
14#include <linux/of.h>
15#include <linux/smp.h>
16#include <linux/mbus.h>
17#include <asm/smp_scu.h>
18#include <asm/smp_plat.h>
19#include "common.h"
20#include "pmsu.h"
21
22extern void mvebu_cortex_a9_secondary_startup(void);
23
24static int mvebu_cortex_a9_boot_secondary(unsigned int cpu,
25 struct task_struct *idle)
26{
27 int ret, hw_cpu;
28
29 pr_info("Booting CPU %d\n", cpu);
30
31 /*
32 * Write the address of secondary startup into the system-wide
33 * flags register. The boot monitor waits until it receives a
34 * soft interrupt, and then the secondary CPU branches to this
35 * address.
36 */
37 hw_cpu = cpu_logical_map(cpu);
38 if (of_machine_is_compatible(compat: "marvell,armada375"))
39 mvebu_system_controller_set_cpu_boot_addr(boot_addr: mvebu_cortex_a9_secondary_startup);
40 else
41 mvebu_pmsu_set_cpu_boot_addr(hw_cpu, boot_addr: mvebu_cortex_a9_secondary_startup);
42 smp_wmb();
43
44 /*
45 * Doing this before deasserting the CPUs is needed to wake up CPUs
46 * in the offline state after using CPU hotplug.
47 */
48 arch_send_wakeup_ipi_mask(cpumask_of(cpu));
49
50 ret = mvebu_cpu_reset_deassert(cpu: hw_cpu);
51 if (ret) {
52 pr_err("Could not start the secondary CPU: %d\n", ret);
53 return ret;
54 }
55
56 return 0;
57}
58/*
59 * When a CPU is brought back online, either through CPU hotplug, or
60 * because of the boot of a kexec'ed kernel, the PMSU configuration
61 * for this CPU might be in the deep idle state, preventing this CPU
62 * from receiving interrupts. Here, we therefore take out the current
63 * CPU from this state, which was entered by armada_38x_cpu_die()
64 * below.
65 */
66static void armada_38x_secondary_init(unsigned int cpu)
67{
68 mvebu_v7_pmsu_idle_exit();
69}
70
71#ifdef CONFIG_HOTPLUG_CPU
72static void armada_38x_cpu_die(unsigned int cpu)
73{
74 /*
75 * CPU hotplug is implemented by putting offline CPUs into the
76 * deep idle sleep state.
77 */
78 armada_38x_do_cpu_suspend(deepidle: true);
79}
80
81/*
82 * We need a dummy function, so that platform_can_cpu_hotplug() knows
83 * we support CPU hotplug. However, the function does not need to do
84 * anything, because CPUs going offline can enter the deep idle state
85 * by themselves, without any help from a still alive CPU.
86 */
87static int armada_38x_cpu_kill(unsigned int cpu)
88{
89 return 1;
90}
91#endif
92
93static const struct smp_operations mvebu_cortex_a9_smp_ops __initconst = {
94 .smp_boot_secondary = mvebu_cortex_a9_boot_secondary,
95};
96
97static const struct smp_operations armada_38x_smp_ops __initconst = {
98 .smp_boot_secondary = mvebu_cortex_a9_boot_secondary,
99 .smp_secondary_init = armada_38x_secondary_init,
100#ifdef CONFIG_HOTPLUG_CPU
101 .cpu_die = armada_38x_cpu_die,
102 .cpu_kill = armada_38x_cpu_kill,
103#endif
104};
105
106CPU_METHOD_OF_DECLARE(mvebu_armada_375_smp, "marvell,armada-375-smp",
107 &mvebu_cortex_a9_smp_ops);
108CPU_METHOD_OF_DECLARE(mvebu_armada_380_smp, "marvell,armada-380-smp",
109 &armada_38x_smp_ops);
110CPU_METHOD_OF_DECLARE(mvebu_armada_390_smp, "marvell,armada-390-smp",
111 &armada_38x_smp_ops);
112

source code of linux/arch/arm/mach-mvebu/platsmp-a9.c