1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * SMP support for SoCs with SCU covered by mach-shmobile
4 *
5 * Copyright (C) 2013 Magnus Damm
6 */
7 #include <linux/cpu.h>
8 #include <linux/delay.h>
9 #include <linux/init.h>
10 #include <linux/io.h>
11 #include <linux/smp.h>
12 #include <asm/cacheflush.h>
13 #include <asm/smp_plat.h>
14 #include <asm/smp_scu.h>
15 #include "common.h"
16
17
18 static phys_addr_t shmobile_scu_base_phys;
19 static void __iomem *shmobile_scu_base;
20
shmobile_scu_cpu_prepare(unsigned int cpu)21 static int shmobile_scu_cpu_prepare(unsigned int cpu)
22 {
23 /* For this particular CPU register SCU SMP boot vector */
24 shmobile_smp_hook(cpu, __pa_symbol(shmobile_boot_scu),
25 shmobile_scu_base_phys);
26 return 0;
27 }
28
shmobile_smp_scu_prepare_cpus(phys_addr_t scu_base_phys,unsigned int max_cpus)29 void __init shmobile_smp_scu_prepare_cpus(phys_addr_t scu_base_phys,
30 unsigned int max_cpus)
31 {
32 /* install boot code shared by all CPUs */
33 shmobile_boot_fn = __pa_symbol(shmobile_smp_boot);
34
35 /* enable SCU and cache coherency on booting CPU */
36 shmobile_scu_base_phys = scu_base_phys;
37 shmobile_scu_base = ioremap(scu_base_phys, PAGE_SIZE);
38 scu_enable(shmobile_scu_base);
39 scu_power_mode(shmobile_scu_base, SCU_PM_NORMAL);
40
41 /* Use CPU notifier for reset vector control */
42 cpuhp_setup_state_nocalls(CPUHP_ARM_SHMOBILE_SCU_PREPARE,
43 "arm/shmobile-scu:prepare",
44 shmobile_scu_cpu_prepare, NULL);
45 }
46
47 #ifdef CONFIG_HOTPLUG_CPU
shmobile_smp_scu_cpu_die(unsigned int cpu)48 void shmobile_smp_scu_cpu_die(unsigned int cpu)
49 {
50 /* For this particular CPU deregister boot vector */
51 shmobile_smp_hook(cpu, 0, 0);
52
53 dsb();
54 flush_cache_all();
55
56 /* disable cache coherency */
57 scu_power_mode(shmobile_scu_base, SCU_PM_POWEROFF);
58
59 /* jump to shared mach-shmobile sleep / reset code */
60 shmobile_smp_sleep();
61 }
62
shmobile_smp_scu_psr_core_disabled(int cpu)63 static int shmobile_smp_scu_psr_core_disabled(int cpu)
64 {
65 unsigned long mask = SCU_PM_POWEROFF << (cpu * 8);
66
67 if ((readl(shmobile_scu_base + 8) & mask) == mask)
68 return 1;
69
70 return 0;
71 }
72
shmobile_smp_scu_cpu_kill(unsigned int cpu)73 int shmobile_smp_scu_cpu_kill(unsigned int cpu)
74 {
75 int k;
76
77 /* this function is running on another CPU than the offline target,
78 * here we need wait for shutdown code in platform_cpu_die() to
79 * finish before asking SoC-specific code to power off the CPU core.
80 */
81 for (k = 0; k < 1000; k++) {
82 if (shmobile_smp_scu_psr_core_disabled(cpu))
83 return 1;
84
85 mdelay(1);
86 }
87
88 return 0;
89 }
90 #endif
91