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
shmobile_smp_scu_notifier_call(struct notifier_block * nfb,unsigned long action,void * hcpu)20 static 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
36 static struct notifier_block shmobile_smp_scu_notifier = {
37 .notifier_call = shmobile_smp_scu_notifier_call,
38 };
39
shmobile_smp_scu_prepare_cpus(unsigned int max_cpus)40 void __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
shmobile_smp_scu_cpu_die(unsigned int cpu)55 void 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
shmobile_smp_scu_psr_core_disabled(int cpu)70 static 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
shmobile_smp_scu_cpu_kill(unsigned int cpu)80 int 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