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 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 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 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 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 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