arch/arm/mach-vexpress/tc2_pm.c

   1 /*
   2  * arch/arm/mach-vexpress/tc2_pm.c - TC2 power management support
   3  *
   4  * Created by:  Nicolas Pitre, October 2012
   5  * Copyright:   (C) 2012  Linaro Limited
   6  *
   7  * Some portions of this file were originally written by Achin Gupta
   8  * Copyright:   (C) 2012  ARM Limited
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License version 2 as
  12  * published by the Free Software Foundation.
  13  */
  14
  15 #include <linux/init.h>
  16 #include <linux/kernel.h>
  17 #include <linux/spinlock.h>
  18 #include <linux/errno.h>
  19 #include <linux/irqchip/arm-gic.h>
  20
  21 #include <asm/mcpm.h>
  22 #include <asm/proc-fns.h>
  23 #include <asm/cacheflush.h>
  24 #include <asm/cputype.h>
  25 #include <asm/cp15.h>
  26 #include <asm/psci.h>
  27
  28 #include <mach/motherboard.h>
  29 #include <mach/tc2.h>
  30
  31 #include <linux/vexpress.h>
  32 #include <linux/arm-cci.h>
  33
  34 /*
  35  * We can't use regular spinlocks. In the switcher case, it is possible
  36  * for an outbound CPU to call power_down() after its inbound counterpart
  37  * is already live using the same logical CPU number which trips lockdep
  38  * debugging.
  39  */
  40 static arch_spinlock_t tc2_pm_lock = __ARCH_SPIN_LOCK_UNLOCKED;
  41
  42 static int tc2_pm_use_count[TC2_MAX_CPUS][TC2_MAX_CLUSTERS];
  43
  44 static int tc2_pm_power_up(unsigned int cpu, unsigned int cluster)
  45 {
  46         pr_debug("%s: cpu %u cluster %u\n", __func__, cpu, cluster);
  47         if (cluster >= TC2_MAX_CLUSTERS ||
  48             cpu >= vexpress_spc_get_nb_cpus(cluster))
  49                 return -EINVAL;
  50
  51         /*
  52          * Since this is called with IRQs enabled, and no arch_spin_lock_irq
  53          * variant exists, we need to disable IRQs manually here.
  54          */
  55         local_irq_disable();
  56         arch_spin_lock(&tc2_pm_lock);
  57
  58         if (!tc2_pm_use_count[0][cluster] &&
  59             !tc2_pm_use_count[1][cluster] &&
  60             !tc2_pm_use_count[2][cluster])
  61                 vexpress_spc_powerdown_enable(cluster, 0);
  62
  63         tc2_pm_use_count[cpu][cluster]++;
  64         if (tc2_pm_use_count[cpu][cluster] == 1) {
  65                 vexpress_spc_write_resume_reg(cluster, cpu,
  66                                               virt_to_phys(mcpm_entry_point));
  67                 vexpress_spc_set_cpu_wakeup_irq(cpu, cluster, 1);
  68         } else if (tc2_pm_use_count[cpu][cluster] != 2) {
  69                 /*
  70                  * The only possible values are:
  71                  * 0 = CPU down
  72                  * 1 = CPU (still) up
  73                  * 2 = CPU requested to be up before it had a chance
  74                  *     to actually make itself down.
  75                  * Any other value is a bug.
  76                  */
  77                 BUG();
  78         }
  79
  80         arch_spin_unlock(&tc2_pm_lock);
  81         local_irq_enable();
  82
  83         return 0;
  84 }
  85
  86 static void tc2_pm_down(u64 residency)
  87 {
  88         unsigned int mpidr, cpu, cluster;
  89         bool last_man = false, skip_wfi = false;
  90
  91         mpidr = read_cpuid_mpidr();
  92         cpu = MPIDR_AFFINITY_LEVEL(mpidr, 0);
  93         cluster = MPIDR_AFFINITY_LEVEL(mpidr, 1);
  94
  95         pr_debug("%s: cpu %u cluster %u\n", __func__, cpu, cluster);
  96         BUG_ON(cluster >= TC2_MAX_CLUSTERS ||
  97                cpu >= vexpress_spc_get_nb_cpus(cluster));
  98
  99         __mcpm_cpu_going_down(cpu, cluster);
 100
 101         arch_spin_lock(&tc2_pm_lock);
 102         BUG_ON(__mcpm_cluster_state(cluster) != CLUSTER_UP);
 103         tc2_pm_use_count[cpu][cluster]--;
 104         if (tc2_pm_use_count[cpu][cluster] == 0) {
 105                 vexpress_spc_set_cpu_wakeup_irq(cpu, cluster, 1);
 106                 if (!tc2_pm_use_count[0][cluster] &&
 107                     !tc2_pm_use_count[1][cluster] &&
 108                     !tc2_pm_use_count[2][cluster] &&
 109                     (!residency || residency > 5000)) {
 110                         vexpress_spc_powerdown_enable(cluster, 1);
 111                         vexpress_spc_set_global_wakeup_intr(1);
 112                         last_man = true;
 113                 }
 114         } else if (tc2_pm_use_count[cpu][cluster] == 1) {
 115                 /*
 116                  * A power_up request went ahead of us.
 117                  * Even if we do not want to shut this CPU down,
 118                  * the caller expects a certain state as if the WFI
 119                  * was aborted.  So let's continue with cache cleaning.
 120                  */
 121                 skip_wfi = true;
 122         } else
 123                 BUG();
 124
 125         gic_cpu_if_down();
 126
 127         if (last_man && __mcpm_outbound_enter_critical(cpu, cluster)) {
 128                 arch_spin_unlock(&tc2_pm_lock);
 129
 130                 set_cr(get_cr() & ~CR_C);
 131                 flush_cache_all();
 132                 asm volatile ("clrex");
 133                 set_auxcr(get_auxcr() & ~(1 << 6));
 134
 135                 cci_disable_port_by_cpu(mpidr);
 136
 137                 /*
 138                  * Ensure that both C & I bits are disabled in the SCTLR
 139                  * before disabling ACE snoops. This ensures that no
 140                  * coherency traffic will originate from this cpu after
 141                  * ACE snoops are turned off.
 142                  */
 143                 cpu_proc_fin();
 144
 145                 __mcpm_outbound_leave_critical(cluster, CLUSTER_DOWN);
 146         } else {
 147                 /*
 148                  * If last man then undo any setup done previously.
 149                  */
 150                 if (last_man) {
 151                         vexpress_spc_powerdown_enable(cluster, 0);
 152                         vexpress_spc_set_global_wakeup_intr(0);
 153                 }
 154
 155                 arch_spin_unlock(&tc2_pm_lock);
 156
 157                 set_cr(get_cr() & ~CR_C);
 158                 flush_cache_louis();
 159                 asm volatile ("clrex");
 160                 set_auxcr(get_auxcr() & ~(1 << 6));
 161         }
 162
 163         __mcpm_cpu_down(cpu, cluster);
 164
 165         /* Now we are prepared for power-down, do it: */
 166         if (!skip_wfi)
 167                 wfi();
 168
 169         /* Not dead at this point?  Let our caller cope. */
 170 }
 171
 172 static void tc2_pm_power_down(void)
 173 {
 174         tc2_pm_down(0);
 175 }
 176
 177 static void tc2_pm_suspend(u64 residency)
 178 {
 179         extern void tc2_resume(void);
 180         unsigned int mpidr, cpu, cluster;
 181
 182         mpidr = read_cpuid_mpidr();
 183         cpu = MPIDR_AFFINITY_LEVEL(mpidr, 0);
 184         cluster = MPIDR_AFFINITY_LEVEL(mpidr, 1);
 185         vexpress_spc_write_resume_reg(cluster, cpu,
 186                                       virt_to_phys(tc2_resume));
 187
 188         tc2_pm_down(residency);
 189 }
 190
 191 static void tc2_pm_powered_up(void)
 192 {
 193         unsigned int mpidr, cpu, cluster;
 194         unsigned long flags;
 195
 196         mpidr = read_cpuid_mpidr();
 197         cpu = MPIDR_AFFINITY_LEVEL(mpidr, 0);
 198         cluster = MPIDR_AFFINITY_LEVEL(mpidr, 1);
 199
 200         pr_debug("%s: cpu %u cluster %u\n", __func__, cpu, cluster);
 201         BUG_ON(cluster >= TC2_MAX_CLUSTERS ||
 202                cpu >= vexpress_spc_get_nb_cpus(cluster));
 203
 204         local_irq_save(flags);
 205         arch_spin_lock(&tc2_pm_lock);
 206
 207         if (!tc2_pm_use_count[0][cluster] &&
 208             !tc2_pm_use_count[1][cluster] &&
 209             !tc2_pm_use_count[2][cluster]) {
 210                 vexpress_spc_powerdown_enable(cluster, 0);
 211                 vexpress_spc_set_global_wakeup_intr(0);
 212         }
 213
 214         if (!tc2_pm_use_count[cpu][cluster])
 215                 tc2_pm_use_count[cpu][cluster] = 1;
 216
 217         vexpress_spc_set_cpu_wakeup_irq(cpu, cluster, 0);
 218         vexpress_spc_write_resume_reg(cluster, cpu, 0);
 219
 220         arch_spin_unlock(&tc2_pm_lock);
 221         local_irq_restore(flags);
 222 }
 223
 224 static const struct mcpm_platform_ops tc2_pm_power_ops = {
 225         .power_up       = tc2_pm_power_up,
 226         .power_down     = tc2_pm_power_down,
 227         .suspend        = tc2_pm_suspend,
 228         .powered_up     = tc2_pm_powered_up,
 229 };
 230
 231 static void __init tc2_pm_usage_count_init(void)
 232 {
 233         unsigned int mpidr, cpu, cluster;
 234
 235         mpidr = read_cpuid_mpidr();
 236         cpu = MPIDR_AFFINITY_LEVEL(mpidr, 0);
 237         cluster = MPIDR_AFFINITY_LEVEL(mpidr, 1);
 238
 239         pr_debug("%s: cpu %u cluster %u\n", __func__, cpu, cluster);
 240         BUG_ON(cluster >= TC2_MAX_CLUSTERS ||
 241                cpu >= vexpress_spc_get_nb_cpus(cluster));
 242
 243         tc2_pm_use_count[cpu][cluster] = 1;
 244 }
 245
 246 extern void tc2_pm_power_up_setup(unsigned int affinity_level);
 247
 248 static int __init tc2_pm_init(void)
 249 {
 250         int ret;
 251
 252         ret = psci_probe();
 253         if (!ret) {
 254                 pr_debug("psci found. Aborting native init\n");
 255                 return -ENODEV;
 256         }
 257
 258         if (!vexpress_spc_check_loaded())
 259                 return -ENODEV;
 260
 261         tc2_pm_usage_count_init();
 262
 263         ret = mcpm_platform_register(&tc2_pm_power_ops);
 264         if (!ret)
 265                 ret = mcpm_sync_init(tc2_pm_power_up_setup);
 266         if (!ret)
 267                 pr_info("TC2 power management initialized\n");
 268         return ret;
 269 }
 270
 271 early_initcall(tc2_pm_init);