arch/arm/mach-shmobile/platsmp-apmu.c

   1 /*
   2  * SMP support for SoCs with APMU
   3  *
   4  * Copyright (C) 2014  Renesas Electronics Corporation
   5  * Copyright (C) 2013  Magnus Damm
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  */
  11 #include <linux/cpu_pm.h>
  12 #include <linux/delay.h>
  13 #include <linux/init.h>
  14 #include <linux/io.h>
  15 #include <linux/ioport.h>
  16 #include <linux/of_address.h>
  17 #include <linux/smp.h>
  18 #include <linux/suspend.h>
  19 #include <linux/threads.h>
  20 #include <asm/cacheflush.h>
  21 #include <asm/cp15.h>
  22 #include <asm/proc-fns.h>
  23 #include <asm/smp_plat.h>
  24 #include <asm/suspend.h>
  25 #include "common.h"
  26 #include "platsmp-apmu.h"
  27
  28 static struct {
  29         void __iomem *iomem;
  30         int bit;
  31 } apmu_cpus[NR_CPUS];
  32
  33 #define WUPCR_OFFS 0x10
  34 #define PSTR_OFFS 0x40
  35 #define CPUNCR_OFFS(n) (0x100 + (0x10 * (n)))
  36
  37 static int __maybe_unused apmu_power_on(void __iomem *p, int bit)
  38 {
  39         /* request power on */
  40         writel_relaxed(BIT(bit), p + WUPCR_OFFS);
  41
  42         /* wait for APMU to finish */
  43         while (readl_relaxed(p + WUPCR_OFFS) != 0)
  44                 ;
  45
  46         return 0;
  47 }
  48
  49 static int __maybe_unused apmu_power_off(void __iomem *p, int bit)
  50 {
  51         /* request Core Standby for next WFI */
  52         writel_relaxed(3, p + CPUNCR_OFFS(bit));
  53         return 0;
  54 }
  55
  56 static int __maybe_unused apmu_power_off_poll(void __iomem *p, int bit)
  57 {
  58         int k;
  59
  60         for (k = 0; k < 1000; k++) {
  61                 if (((readl_relaxed(p + PSTR_OFFS) >> (bit * 4)) & 0x03) == 3)
  62                         return 1;
  63
  64                 mdelay(1);
  65         }
  66
  67         return 0;
  68 }
  69
  70 static int __maybe_unused apmu_wrap(int cpu, int (*fn)(void __iomem *p, int cpu))
  71 {
  72         void __iomem *p = apmu_cpus[cpu].iomem;
  73
  74         return p ? fn(p, apmu_cpus[cpu].bit) : -EINVAL;
  75 }
  76
  77 static void apmu_init_cpu(struct resource *res, int cpu, int bit)
  78 {
  79         if ((cpu >= ARRAY_SIZE(apmu_cpus)) || apmu_cpus[cpu].iomem)
  80                 return;
  81
  82         apmu_cpus[cpu].iomem = ioremap_nocache(res->start, resource_size(res));
  83         apmu_cpus[cpu].bit = bit;
  84
  85         pr_debug("apmu ioremap %d %d %pr\n", cpu, bit, res);
  86 }
  87
  88 static void apmu_parse_cfg(void (*fn)(struct resource *res, int cpu, int bit),
  89                            struct rcar_apmu_config *apmu_config, int num)
  90 {
  91         int id;
  92         int k;
  93         int bit, index;
  94         bool is_allowed;
  95
  96         for (k = 0; k < num; k++) {
  97                 /* only enable the cluster that includes the boot CPU */
  98                 is_allowed = false;
  99                 for (bit = 0; bit < ARRAY_SIZE(apmu_config[k].cpus); bit++) {
 100                         id = apmu_config[k].cpus[bit];
 101                         if (id >= 0) {
 102                                 if (id == cpu_logical_map(0))
 103                                         is_allowed = true;
 104                         }
 105                 }
 106                 if (!is_allowed)
 107                         continue;
 108
 109                 for (bit = 0; bit < ARRAY_SIZE(apmu_config[k].cpus); bit++) {
 110                         id = apmu_config[k].cpus[bit];
 111                         if (id >= 0) {
 112                                 index = get_logical_index(id);
 113                                 if (index >= 0)
 114                                         fn(&apmu_config[k].iomem, index, bit);
 115                         }
 116                 }
 117         }
 118 }
 119
 120 void __init shmobile_smp_apmu_prepare_cpus(unsigned int max_cpus,
 121                                            struct rcar_apmu_config *apmu_config,
 122                                            int num)
 123 {
 124         /* install boot code shared by all CPUs */
 125         shmobile_boot_fn = virt_to_phys(shmobile_smp_boot);
 126
 127         /* perform per-cpu setup */
 128         apmu_parse_cfg(apmu_init_cpu, apmu_config, num);
 129 }
 130
 131 #ifdef CONFIG_SMP
 132 int shmobile_smp_apmu_boot_secondary(unsigned int cpu, struct task_struct *idle)
 133 {
 134         /* For this particular CPU register boot vector */
 135         shmobile_smp_hook(cpu, virt_to_phys(secondary_startup), 0);
 136
 137         return apmu_wrap(cpu, apmu_power_on);
 138 }
 139 #endif
 140
 141 #if defined(CONFIG_HOTPLUG_CPU) || defined(CONFIG_SUSPEND)
 142 /* nicked from arch/arm/mach-exynos/hotplug.c */
 143 static inline void cpu_enter_lowpower_a15(void)
 144 {
 145         unsigned int v;
 146
 147         asm volatile(
 148         "       mrc     p15, 0, %0, c1, c0, 0\n"
 149         "       bic     %0, %0, %1\n"
 150         "       mcr     p15, 0, %0, c1, c0, 0\n"
 151                 : "=&r" (v)
 152                 : "Ir" (CR_C)
 153                 : "cc");
 154
 155         flush_cache_louis();
 156
 157         asm volatile(
 158         /*
 159          * Turn off coherency
 160          */
 161         "       mrc     p15, 0, %0, c1, c0, 1\n"
 162         "       bic     %0, %0, %1\n"
 163         "       mcr     p15, 0, %0, c1, c0, 1\n"
 164                 : "=&r" (v)
 165                 : "Ir" (0x40)
 166                 : "cc");
 167
 168         isb();
 169         dsb();
 170 }
 171
 172 static void shmobile_smp_apmu_cpu_shutdown(unsigned int cpu)
 173 {
 174
 175         /* Select next sleep mode using the APMU */
 176         apmu_wrap(cpu, apmu_power_off);
 177
 178         /* Do ARM specific CPU shutdown */
 179         cpu_enter_lowpower_a15();
 180 }
 181
 182 static inline void cpu_leave_lowpower(void)
 183 {
 184         unsigned int v;
 185
 186         asm volatile("mrc    p15, 0, %0, c1, c0, 0\n"
 187                      "       orr     %0, %0, %1\n"
 188                      "       mcr     p15, 0, %0, c1, c0, 0\n"
 189                      "       mrc     p15, 0, %0, c1, c0, 1\n"
 190                      "       orr     %0, %0, %2\n"
 191                      "       mcr     p15, 0, %0, c1, c0, 1\n"
 192                      : "=&r" (v)
 193                      : "Ir" (CR_C), "Ir" (0x40)
 194                      : "cc");
 195 }
 196 #endif
 197
 198 #if defined(CONFIG_HOTPLUG_CPU)
 199 void shmobile_smp_apmu_cpu_die(unsigned int cpu)
 200 {
 201         /* For this particular CPU deregister boot vector */
 202         shmobile_smp_hook(cpu, 0, 0);
 203
 204         /* Shutdown CPU core */
 205         shmobile_smp_apmu_cpu_shutdown(cpu);
 206
 207         /* jump to shared mach-shmobile sleep / reset code */
 208         shmobile_smp_sleep();
 209 }
 210
 211 int shmobile_smp_apmu_cpu_kill(unsigned int cpu)
 212 {
 213         return apmu_wrap(cpu, apmu_power_off_poll);
 214 }
 215 #endif
 216
 217 #if defined(CONFIG_SUSPEND)
 218 static int shmobile_smp_apmu_do_suspend(unsigned long cpu)
 219 {
 220         shmobile_smp_hook(cpu, virt_to_phys(cpu_resume), 0);
 221         shmobile_smp_apmu_cpu_shutdown(cpu);
 222         cpu_do_idle(); /* WFI selects Core Standby */
 223         return 1;
 224 }
 225
 226 static int shmobile_smp_apmu_enter_suspend(suspend_state_t state)
 227 {
 228         cpu_suspend(smp_processor_id(), shmobile_smp_apmu_do_suspend);
 229         cpu_leave_lowpower();
 230         return 0;
 231 }
 232
 233 void __init shmobile_smp_apmu_suspend_init(void)
 234 {
 235         shmobile_suspend_ops.enter = shmobile_smp_apmu_enter_suspend;
 236 }
 237 #endif