1/*
2 * SMP support for SoCs with SCU covered by mach-shmobile
3 *
4 * Copyright (C) 2013  Magnus Damm
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 */
10#include <linux/cpu.h>
11#include <linux/delay.h>
12#include <linux/init.h>
13#include <linux/io.h>
14#include <linux/smp.h>
15#include <asm/cacheflush.h>
16#include <asm/smp_plat.h>
17#include <asm/smp_scu.h>
18#include "common.h"
19
20static int shmobile_smp_scu_notifier_call(struct notifier_block *nfb,
21					  unsigned long action, void *hcpu)
22{
23	unsigned int cpu = (long)hcpu;
24
25	switch (action) {
26	case CPU_UP_PREPARE:
27		/* For this particular CPU register SCU SMP boot vector */
28		shmobile_smp_hook(cpu, virt_to_phys(shmobile_boot_scu),
29				  (unsigned long)shmobile_scu_base);
30		break;
31	};
32
33	return NOTIFY_OK;
34}
35
36static struct notifier_block shmobile_smp_scu_notifier = {
37	.notifier_call = shmobile_smp_scu_notifier_call,
38};
39
40void __init shmobile_smp_scu_prepare_cpus(unsigned int max_cpus)
41{
42	/* install boot code shared by all CPUs */
43	shmobile_boot_fn = virt_to_phys(shmobile_smp_boot);
44	shmobile_boot_arg = MPIDR_HWID_BITMASK;
45
46	/* enable SCU and cache coherency on booting CPU */
47	scu_enable(shmobile_scu_base);
48	scu_power_mode(shmobile_scu_base, SCU_PM_NORMAL);
49
50	/* Use CPU notifier for reset vector control */
51	register_cpu_notifier(&shmobile_smp_scu_notifier);
52}
53
54#ifdef CONFIG_HOTPLUG_CPU
55void shmobile_smp_scu_cpu_die(unsigned int cpu)
56{
57	/* For this particular CPU deregister boot vector */
58	shmobile_smp_hook(cpu, 0, 0);
59
60	dsb();
61	flush_cache_all();
62
63	/* disable cache coherency */
64	scu_power_mode(shmobile_scu_base, SCU_PM_POWEROFF);
65
66	/* jump to shared mach-shmobile sleep / reset code */
67	shmobile_smp_sleep();
68}
69
70static int shmobile_smp_scu_psr_core_disabled(int cpu)
71{
72	unsigned long mask = SCU_PM_POWEROFF << (cpu * 8);
73
74	if ((__raw_readl(shmobile_scu_base + 8) & mask) == mask)
75		return 1;
76
77	return 0;
78}
79
80int shmobile_smp_scu_cpu_kill(unsigned int cpu)
81{
82	int k;
83
84	/* this function is running on another CPU than the offline target,
85	 * here we need wait for shutdown code in platform_cpu_die() to
86	 * finish before asking SoC-specific code to power off the CPU core.
87	 */
88	for (k = 0; k < 1000; k++) {
89		if (shmobile_smp_scu_psr_core_disabled(cpu))
90			return 1;
91
92		mdelay(1);
93	}
94
95	return 0;
96}
97#endif
98