// SPDX-License-Identifier: GPL-2.0-only /* * Copyright (c) 2012 Linaro : Daniel Lezcano <daniel.lezcano@linaro.org> (IBM) * * Based on the work of Rickard Andersson <rickard.andersson@stericsson.com> * and Jonas Aaberg <jonas.aberg@stericsson.com>. */ #include <linux/init.h> #include <linux/cpuidle.h> #include <linux/spinlock.h> #include <linux/atomic.h> #include <linux/smp.h> #include <linux/mfd/dbx500-prcmu.h> #include <linux/platform_data/arm-ux500-pm.h> #include <linux/platform_device.h> #include <asm/cpuidle.h> static atomic_t master = ATOMIC_INIT(0); static DEFINE_SPINLOCK(master_lock); static inline int ux500_enter_idle(struct cpuidle_device *dev, struct cpuidle_driver *drv, int index) { int this_cpu = smp_processor_id(); bool recouple = false; if (atomic_inc_return(&master) == num_online_cpus()) { /* With this lock, we prevent the other cpu to exit and enter * this function again and become the master */ if (!spin_trylock(&master_lock)) goto wfi; /* decouple the gic from the A9 cores */ if (prcmu_gic_decouple()) { spin_unlock(&master_lock); goto out; } /* If an error occur, we will have to recouple the gic * manually */ recouple = true; /* At this state, as the gic is decoupled, if the other * cpu is in WFI, we have the guarantee it won't be wake * up, so we can safely go to retention */ if (!prcmu_is_cpu_in_wfi(this_cpu ? 0 : 1)) goto out; /* The prcmu will be in charge of watching the interrupts * and wake up the cpus */ if (prcmu_copy_gic_settings()) goto out; /* Check in the meantime an interrupt did * not occur on the gic ... */ if (prcmu_gic_pending_irq()) goto out; /* ... and the prcmu */ if (prcmu_pending_irq()) goto out; /* Go to the retention state, the prcmu will wait for the * cpu to go WFI and this is what happens after exiting this * 'master' critical section */ if (prcmu_set_power_state(PRCMU_AP_IDLE, true, true)) goto out; /* When we switch to retention, the prcmu is in charge * of recoupling the gic automatically */ recouple = false; spin_unlock(&master_lock); } wfi: cpu_do_idle(); out: atomic_dec(&master); if (recouple) { prcmu_gic_recouple(); spin_unlock(&master_lock); } return index; } static struct cpuidle_driver ux500_idle_driver = { .name = "ux500_idle", .owner = THIS_MODULE, .states = { ARM_CPUIDLE_WFI_STATE, { .enter = ux500_enter_idle, .exit_latency = 70, .target_residency = 260, .flags = CPUIDLE_FLAG_TIMER_STOP, .name = "ApIdle", .desc = "ARM Retention", }, }, .safe_state_index = 0, .state_count = 2, }; static int dbx500_cpuidle_probe(struct platform_device *pdev) { /* Configure wake up reasons */ prcmu_enable_wakeups(PRCMU_WAKEUP(ARM) | PRCMU_WAKEUP(RTC) | PRCMU_WAKEUP(ABB)); return cpuidle_register(&ux500_idle_driver, NULL); } static struct platform_driver dbx500_cpuidle_plat_driver = { .driver = { .name = "cpuidle-dbx500", }, .probe = dbx500_cpuidle_probe, }; builtin_platform_driver(dbx500_cpuidle_plat_driver);