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 | |
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 | arg: shmobile_scu_base_phys); |
26 | return 0; |
27 | } |
28 | |
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(offset: 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(state: CPUHP_ARM_SHMOBILE_SCU_PREPARE, |
43 | name: "arm/shmobile-scu:prepare" , |
44 | startup: shmobile_scu_cpu_prepare, NULL); |
45 | } |
46 | |
47 | #ifdef CONFIG_HOTPLUG_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, fn: 0, arg: 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 | |
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(addr: shmobile_scu_base + 8) & mask) == mask) |
68 | return 1; |
69 | |
70 | return 0; |
71 | } |
72 | |
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 | |