/* * arch/arm/mach-vexpress/tc2_pm.c - TC2 power management support * * Created by: Nicolas Pitre, October 2012 * Copyright: (C) 2012 Linaro Limited * * Some portions of this file were originally written by Achin Gupta * Copyright: (C) 2012 ARM Limited * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. */ #include #include #include #include #include #include #include #include #include #include #include #include #include /* * We can't use regular spinlocks. In the switcher case, it is possible * for an outbound CPU to call power_down() after its inbound counterpart * is already live using the same logical CPU number which trips lockdep * debugging. */ static arch_spinlock_t tc2_pm_lock = __ARCH_SPIN_LOCK_UNLOCKED; static int tc2_pm_use_count[3][2]; static int tc2_pm_power_up(unsigned int cpu, unsigned int cluster) { pr_debug("%s: cpu %u cluster %u\n", __func__, cpu, cluster); if (cluster >= 2 || cpu >= vexpress_spc_get_nb_cpus(cluster)) return -EINVAL; /* * Since this is called with IRQs enabled, and no arch_spin_lock_irq * variant exists, we need to disable IRQs manually here. */ local_irq_disable(); arch_spin_lock(&tc2_pm_lock); if (!tc2_pm_use_count[0][cluster] && !tc2_pm_use_count[1][cluster] && !tc2_pm_use_count[2][cluster]) vexpress_spc_powerdown_enable(cluster, 0); tc2_pm_use_count[cpu][cluster]++; if (tc2_pm_use_count[cpu][cluster] == 1) { vexpress_spc_write_bxaddr_reg(cluster, cpu, virt_to_phys(mcpm_entry_point)); vexpress_spc_set_cpu_wakeup_irq(cpu, cluster, 1); } else if (tc2_pm_use_count[cpu][cluster] != 2) { /* * The only possible values are: * 0 = CPU down * 1 = CPU (still) up * 2 = CPU requested to be up before it had a chance * to actually make itself down. * Any other value is a bug. */ BUG(); } arch_spin_unlock(&tc2_pm_lock); local_irq_enable(); return 0; } static void tc2_pm_power_down(void) { unsigned int mpidr, cpu, cluster; bool last_man = false, skip_wfi = false; mpidr = read_cpuid_mpidr(); cpu = MPIDR_AFFINITY_LEVEL(mpidr, 0); cluster = MPIDR_AFFINITY_LEVEL(mpidr, 1); pr_debug("%s: cpu %u cluster %u\n", __func__, cpu, cluster); BUG_ON(cluster >= 2 || cpu >= vexpress_spc_get_nb_cpus(cluster)); __mcpm_cpu_going_down(cpu, cluster); arch_spin_lock(&tc2_pm_lock); BUG_ON(__mcpm_cluster_state(cluster) != CLUSTER_UP); tc2_pm_use_count[cpu][cluster]--; if (tc2_pm_use_count[cpu][cluster] == 0) { vexpress_spc_set_cpu_wakeup_irq(cpu, cluster, 1); if (!tc2_pm_use_count[0][cluster] && !tc2_pm_use_count[1][cluster] && !tc2_pm_use_count[2][cluster]) { vexpress_spc_powerdown_enable(cluster, 1); vexpress_spc_set_global_wakeup_intr(1); last_man = true; } } else if (tc2_pm_use_count[cpu][cluster] == 1) { /* * A power_up request went ahead of us. * Even if we do not want to shut this CPU down, * the caller expects a certain state as if the WFI * was aborted. So let's continue with cache cleaning. */ skip_wfi = true; } else BUG(); gic_cpu_if_down(); if (last_man && __mcpm_outbound_enter_critical(cpu, cluster)) { arch_spin_unlock(&tc2_pm_lock); set_cr(get_cr() & ~CR_C); flush_cache_all(); asm volatile ("clrex"); set_auxcr(get_auxcr() & ~(1 << 6)); disable_cci(cluster); /* * Ensure that both C & I bits are disabled in the SCTLR * before disabling ACE snoops. This ensures that no * coherency traffic will originate from this cpu after * ACE snoops are turned off. */ cpu_proc_fin(); __mcpm_outbound_leave_critical(cluster, CLUSTER_DOWN); } else { /* * If last man then undo any setup done previously. */ if (last_man) { vexpress_spc_powerdown_enable(cluster, 0); vexpress_spc_set_global_wakeup_intr(0); } arch_spin_unlock(&tc2_pm_lock); set_cr(get_cr() & ~CR_C); flush_cache_louis(); asm volatile ("clrex"); set_auxcr(get_auxcr() & ~(1 << 6)); } __mcpm_cpu_down(cpu, cluster); /* Now we are prepared for power-down, do it: */ if (!skip_wfi) wfi(); /* Not dead at this point? Let our caller cope. */ } static void tc2_pm_powered_up(void) { unsigned int mpidr, cpu, cluster; unsigned long flags; mpidr = read_cpuid_mpidr(); cpu = MPIDR_AFFINITY_LEVEL(mpidr, 0); cluster = MPIDR_AFFINITY_LEVEL(mpidr, 1); pr_debug("%s: cpu %u cluster %u\n", __func__, cpu, cluster); BUG_ON(cluster >= 2 || cpu >= vexpress_spc_get_nb_cpus(cluster)); local_irq_save(flags); arch_spin_lock(&tc2_pm_lock); if (!tc2_pm_use_count[0][cluster] && !tc2_pm_use_count[1][cluster] && !tc2_pm_use_count[2][cluster]) { vexpress_spc_powerdown_enable(cluster, 0); vexpress_spc_set_global_wakeup_intr(0); } if (!tc2_pm_use_count[cpu][cluster]) tc2_pm_use_count[cpu][cluster] = 1; vexpress_spc_set_cpu_wakeup_irq(cpu, cluster, 0); vexpress_spc_write_bxaddr_reg(cluster, cpu, 0); arch_spin_unlock(&tc2_pm_lock); local_irq_restore(flags); } static const struct mcpm_platform_ops tc2_pm_power_ops = { .power_up = tc2_pm_power_up, .power_down = tc2_pm_power_down, .powered_up = tc2_pm_powered_up, }; static void __init tc2_pm_usage_count_init(void) { unsigned int mpidr, cpu, cluster; mpidr = read_cpuid_mpidr(); cpu = MPIDR_AFFINITY_LEVEL(mpidr, 0); cluster = MPIDR_AFFINITY_LEVEL(mpidr, 1); pr_debug("%s: cpu %u cluster %u\n", __func__, cpu, cluster); BUG_ON(cpu >= 3 || cluster >= 2); tc2_pm_use_count[cpu][cluster] = 1; } extern void tc2_pm_power_up_setup(unsigned int affinity_level); static int __init tc2_pm_init(void) { int ret; if (!vexpress_spc_check_loaded()) return -ENODEV; tc2_pm_usage_count_init(); ret = mcpm_platform_register(&tc2_pm_power_ops); if (!ret) ret = mcpm_sync_init(tc2_pm_power_up_setup); if (!ret) pr_info("TC2 power management initialized\n"); return ret; } early_initcall(tc2_pm_init);