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 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(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 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 63 static int shmobile_smp_scu_psr_core_disabled(int cpu) 64 { 65 unsigned long mask = SCU_PM_POWEROFF << (cpu * 8); 66 67 if ((__raw_readl(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