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 20 21 static phys_addr_t shmobile_scu_base_phys; 22 static void __iomem *shmobile_scu_base; 23 24 static int shmobile_scu_cpu_prepare(unsigned int cpu) 25 { 26 /* For this particular CPU register SCU SMP boot vector */ 27 shmobile_smp_hook(cpu, virt_to_phys(shmobile_boot_scu), 28 shmobile_scu_base_phys); 29 return 0; 30 } 31 32 void __init shmobile_smp_scu_prepare_cpus(phys_addr_t scu_base_phys, 33 unsigned int max_cpus) 34 { 35 /* install boot code shared by all CPUs */ 36 shmobile_boot_fn = virt_to_phys(shmobile_smp_boot); 37 38 /* enable SCU and cache coherency on booting CPU */ 39 shmobile_scu_base_phys = scu_base_phys; 40 shmobile_scu_base = ioremap(scu_base_phys, PAGE_SIZE); 41 scu_enable(shmobile_scu_base); 42 scu_power_mode(shmobile_scu_base, SCU_PM_NORMAL); 43 44 /* Use CPU notifier for reset vector control */ 45 cpuhp_setup_state_nocalls(CPUHP_ARM_SHMOBILE_SCU_PREPARE, 46 "arm/shmobile-scu:prepare", 47 shmobile_scu_cpu_prepare, NULL); 48 } 49 50 #ifdef CONFIG_HOTPLUG_CPU 51 void shmobile_smp_scu_cpu_die(unsigned int cpu) 52 { 53 /* For this particular CPU deregister boot vector */ 54 shmobile_smp_hook(cpu, 0, 0); 55 56 dsb(); 57 flush_cache_all(); 58 59 /* disable cache coherency */ 60 scu_power_mode(shmobile_scu_base, SCU_PM_POWEROFF); 61 62 /* jump to shared mach-shmobile sleep / reset code */ 63 shmobile_smp_sleep(); 64 } 65 66 static int shmobile_smp_scu_psr_core_disabled(int cpu) 67 { 68 unsigned long mask = SCU_PM_POWEROFF << (cpu * 8); 69 70 if ((__raw_readl(shmobile_scu_base + 8) & mask) == mask) 71 return 1; 72 73 return 0; 74 } 75 76 int shmobile_smp_scu_cpu_kill(unsigned int cpu) 77 { 78 int k; 79 80 /* this function is running on another CPU than the offline target, 81 * here we need wait for shutdown code in platform_cpu_die() to 82 * finish before asking SoC-specific code to power off the CPU core. 83 */ 84 for (k = 0; k < 1000; k++) { 85 if (shmobile_smp_scu_psr_core_disabled(cpu)) 86 return 1; 87 88 mdelay(1); 89 } 90 91 return 0; 92 } 93 #endif 94