From 57f0f512b273f60d52568b8c6b77e17f5636edc0 Mon Sep 17 00:00:00 2001 From: André Fabian Silva Delgado Date: Wed, 5 Aug 2015 17:04:01 -0300 Subject: Initial import --- arch/arm/common/mcpm_entry.c | 486 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 486 insertions(+) create mode 100644 arch/arm/common/mcpm_entry.c (limited to 'arch/arm/common/mcpm_entry.c') diff --git a/arch/arm/common/mcpm_entry.c b/arch/arm/common/mcpm_entry.c new file mode 100644 index 000000000..5f8a52ac7 --- /dev/null +++ b/arch/arm/common/mcpm_entry.c @@ -0,0 +1,486 @@ +/* + * arch/arm/common/mcpm_entry.c -- entry point for multi-cluster PM + * + * Created by: Nicolas Pitre, March 2012 + * Copyright: (C) 2012-2013 Linaro 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 + +extern unsigned long mcpm_entry_vectors[MAX_NR_CLUSTERS][MAX_CPUS_PER_CLUSTER]; + +void mcpm_set_entry_vector(unsigned cpu, unsigned cluster, void *ptr) +{ + unsigned long val = ptr ? virt_to_phys(ptr) : 0; + mcpm_entry_vectors[cluster][cpu] = val; + sync_cache_w(&mcpm_entry_vectors[cluster][cpu]); +} + +extern unsigned long mcpm_entry_early_pokes[MAX_NR_CLUSTERS][MAX_CPUS_PER_CLUSTER][2]; + +void mcpm_set_early_poke(unsigned cpu, unsigned cluster, + unsigned long poke_phys_addr, unsigned long poke_val) +{ + unsigned long *poke = &mcpm_entry_early_pokes[cluster][cpu][0]; + poke[0] = poke_phys_addr; + poke[1] = poke_val; + __sync_cache_range_w(poke, 2 * sizeof(*poke)); +} + +static const struct mcpm_platform_ops *platform_ops; + +int __init mcpm_platform_register(const struct mcpm_platform_ops *ops) +{ + if (platform_ops) + return -EBUSY; + platform_ops = ops; + return 0; +} + +bool mcpm_is_available(void) +{ + return (platform_ops) ? true : false; +} + +/* + * 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 mcpm_lock = __ARCH_SPIN_LOCK_UNLOCKED; + +static int mcpm_cpu_use_count[MAX_NR_CLUSTERS][MAX_CPUS_PER_CLUSTER]; + +static inline bool mcpm_cluster_unused(unsigned int cluster) +{ + int i, cnt; + for (i = 0, cnt = 0; i < MAX_CPUS_PER_CLUSTER; i++) + cnt |= mcpm_cpu_use_count[cluster][i]; + return !cnt; +} + +int mcpm_cpu_power_up(unsigned int cpu, unsigned int cluster) +{ + bool cpu_is_down, cluster_is_down; + int ret = 0; + + if (!platform_ops) + return -EUNATCH; /* try not to shadow power_up errors */ + might_sleep(); + + /* backward compatibility callback */ + if (platform_ops->power_up) + return platform_ops->power_up(cpu, cluster); + + pr_debug("%s: cpu %u cluster %u\n", __func__, cpu, cluster); + + /* + * 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(&mcpm_lock); + + cpu_is_down = !mcpm_cpu_use_count[cluster][cpu]; + cluster_is_down = mcpm_cluster_unused(cluster); + + mcpm_cpu_use_count[cluster][cpu]++; + /* + * 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_ON(mcpm_cpu_use_count[cluster][cpu] != 1 && + mcpm_cpu_use_count[cluster][cpu] != 2); + + if (cluster_is_down) + ret = platform_ops->cluster_powerup(cluster); + if (cpu_is_down && !ret) + ret = platform_ops->cpu_powerup(cpu, cluster); + + arch_spin_unlock(&mcpm_lock); + local_irq_enable(); + return ret; +} + +typedef void (*phys_reset_t)(unsigned long); + +void mcpm_cpu_power_down(void) +{ + unsigned int mpidr, cpu, cluster; + bool cpu_going_down, last_man; + phys_reset_t phys_reset; + + if (WARN_ON_ONCE(!platform_ops)) + return; + BUG_ON(!irqs_disabled()); + + /* + * Do this before calling into the power_down method, + * as it might not always be safe to do afterwards. + */ + setup_mm_for_reboot(); + + /* backward compatibility callback */ + if (platform_ops->power_down) { + platform_ops->power_down(); + goto not_dead; + } + + 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); + + __mcpm_cpu_going_down(cpu, cluster); + + arch_spin_lock(&mcpm_lock); + BUG_ON(__mcpm_cluster_state(cluster) != CLUSTER_UP); + + mcpm_cpu_use_count[cluster][cpu]--; + BUG_ON(mcpm_cpu_use_count[cluster][cpu] != 0 && + mcpm_cpu_use_count[cluster][cpu] != 1); + cpu_going_down = !mcpm_cpu_use_count[cluster][cpu]; + last_man = mcpm_cluster_unused(cluster); + + if (last_man && __mcpm_outbound_enter_critical(cpu, cluster)) { + platform_ops->cpu_powerdown_prepare(cpu, cluster); + platform_ops->cluster_powerdown_prepare(cluster); + arch_spin_unlock(&mcpm_lock); + platform_ops->cluster_cache_disable(); + __mcpm_outbound_leave_critical(cluster, CLUSTER_DOWN); + } else { + if (cpu_going_down) + platform_ops->cpu_powerdown_prepare(cpu, cluster); + arch_spin_unlock(&mcpm_lock); + /* + * If cpu_going_down is false here, that means a power_up + * request raced ahead of us. Even if we do not want to + * shut this CPU down, the caller still expects execution + * to return through the system resume entry path, like + * when the WFI is aborted due to a new IRQ or the like.. + * So let's continue with cache cleaning in all cases. + */ + platform_ops->cpu_cache_disable(); + } + + __mcpm_cpu_down(cpu, cluster); + + /* Now we are prepared for power-down, do it: */ + if (cpu_going_down) + wfi(); + +not_dead: + /* + * It is possible for a power_up request to happen concurrently + * with a power_down request for the same CPU. In this case the + * CPU might not be able to actually enter a powered down state + * with the WFI instruction if the power_up request has removed + * the required reset condition. We must perform a re-entry in + * the kernel as if the power_up method just had deasserted reset + * on the CPU. + */ + phys_reset = (phys_reset_t)(unsigned long)virt_to_phys(cpu_reset); + phys_reset(virt_to_phys(mcpm_entry_point)); + + /* should never get here */ + BUG(); +} + +int mcpm_wait_for_cpu_powerdown(unsigned int cpu, unsigned int cluster) +{ + int ret; + + if (WARN_ON_ONCE(!platform_ops || !platform_ops->wait_for_powerdown)) + return -EUNATCH; + + ret = platform_ops->wait_for_powerdown(cpu, cluster); + if (ret) + pr_warn("%s: cpu %u, cluster %u failed to power down (%d)\n", + __func__, cpu, cluster, ret); + + return ret; +} + +void mcpm_cpu_suspend(u64 expected_residency) +{ + if (WARN_ON_ONCE(!platform_ops)) + return; + + /* backward compatibility callback */ + if (platform_ops->suspend) { + phys_reset_t phys_reset; + BUG_ON(!irqs_disabled()); + setup_mm_for_reboot(); + platform_ops->suspend(expected_residency); + phys_reset = (phys_reset_t)(unsigned long)virt_to_phys(cpu_reset); + phys_reset(virt_to_phys(mcpm_entry_point)); + BUG(); + } + + /* Some platforms might have to enable special resume modes, etc. */ + if (platform_ops->cpu_suspend_prepare) { + unsigned int mpidr = read_cpuid_mpidr(); + unsigned int cpu = MPIDR_AFFINITY_LEVEL(mpidr, 0); + unsigned int cluster = MPIDR_AFFINITY_LEVEL(mpidr, 1); + arch_spin_lock(&mcpm_lock); + platform_ops->cpu_suspend_prepare(cpu, cluster); + arch_spin_unlock(&mcpm_lock); + } + mcpm_cpu_power_down(); +} + +int mcpm_cpu_powered_up(void) +{ + unsigned int mpidr, cpu, cluster; + bool cpu_was_down, first_man; + unsigned long flags; + + if (!platform_ops) + return -EUNATCH; + + /* backward compatibility callback */ + if (platform_ops->powered_up) { + platform_ops->powered_up(); + return 0; + } + + mpidr = read_cpuid_mpidr(); + cpu = MPIDR_AFFINITY_LEVEL(mpidr, 0); + cluster = MPIDR_AFFINITY_LEVEL(mpidr, 1); + local_irq_save(flags); + arch_spin_lock(&mcpm_lock); + + cpu_was_down = !mcpm_cpu_use_count[cluster][cpu]; + first_man = mcpm_cluster_unused(cluster); + + if (first_man && platform_ops->cluster_is_up) + platform_ops->cluster_is_up(cluster); + if (cpu_was_down) + mcpm_cpu_use_count[cluster][cpu] = 1; + if (platform_ops->cpu_is_up) + platform_ops->cpu_is_up(cpu, cluster); + + arch_spin_unlock(&mcpm_lock); + local_irq_restore(flags); + + return 0; +} + +#ifdef CONFIG_ARM_CPU_SUSPEND + +static int __init nocache_trampoline(unsigned long _arg) +{ + void (*cache_disable)(void) = (void *)_arg; + unsigned int mpidr = read_cpuid_mpidr(); + unsigned int cpu = MPIDR_AFFINITY_LEVEL(mpidr, 0); + unsigned int cluster = MPIDR_AFFINITY_LEVEL(mpidr, 1); + phys_reset_t phys_reset; + + mcpm_set_entry_vector(cpu, cluster, cpu_resume); + setup_mm_for_reboot(); + + __mcpm_cpu_going_down(cpu, cluster); + BUG_ON(!__mcpm_outbound_enter_critical(cpu, cluster)); + cache_disable(); + __mcpm_outbound_leave_critical(cluster, CLUSTER_DOWN); + __mcpm_cpu_down(cpu, cluster); + + phys_reset = (phys_reset_t)(unsigned long)virt_to_phys(cpu_reset); + phys_reset(virt_to_phys(mcpm_entry_point)); + BUG(); +} + +int __init mcpm_loopback(void (*cache_disable)(void)) +{ + int ret; + + /* + * We're going to soft-restart the current CPU through the + * low-level MCPM code by leveraging the suspend/resume + * infrastructure. Let's play it safe by using cpu_pm_enter() + * in case the CPU init code path resets the VFP or similar. + */ + local_irq_disable(); + local_fiq_disable(); + ret = cpu_pm_enter(); + if (!ret) { + ret = cpu_suspend((unsigned long)cache_disable, nocache_trampoline); + cpu_pm_exit(); + } + local_fiq_enable(); + local_irq_enable(); + if (ret) + pr_err("%s returned %d\n", __func__, ret); + return ret; +} + +#endif + +struct sync_struct mcpm_sync; + +/* + * __mcpm_cpu_going_down: Indicates that the cpu is being torn down. + * This must be called at the point of committing to teardown of a CPU. + * The CPU cache (SCTRL.C bit) is expected to still be active. + */ +void __mcpm_cpu_going_down(unsigned int cpu, unsigned int cluster) +{ + mcpm_sync.clusters[cluster].cpus[cpu].cpu = CPU_GOING_DOWN; + sync_cache_w(&mcpm_sync.clusters[cluster].cpus[cpu].cpu); +} + +/* + * __mcpm_cpu_down: Indicates that cpu teardown is complete and that the + * cluster can be torn down without disrupting this CPU. + * To avoid deadlocks, this must be called before a CPU is powered down. + * The CPU cache (SCTRL.C bit) is expected to be off. + * However L2 cache might or might not be active. + */ +void __mcpm_cpu_down(unsigned int cpu, unsigned int cluster) +{ + dmb(); + mcpm_sync.clusters[cluster].cpus[cpu].cpu = CPU_DOWN; + sync_cache_w(&mcpm_sync.clusters[cluster].cpus[cpu].cpu); + sev(); +} + +/* + * __mcpm_outbound_leave_critical: Leave the cluster teardown critical section. + * @state: the final state of the cluster: + * CLUSTER_UP: no destructive teardown was done and the cluster has been + * restored to the previous state (CPU cache still active); or + * CLUSTER_DOWN: the cluster has been torn-down, ready for power-off + * (CPU cache disabled, L2 cache either enabled or disabled). + */ +void __mcpm_outbound_leave_critical(unsigned int cluster, int state) +{ + dmb(); + mcpm_sync.clusters[cluster].cluster = state; + sync_cache_w(&mcpm_sync.clusters[cluster].cluster); + sev(); +} + +/* + * __mcpm_outbound_enter_critical: Enter the cluster teardown critical section. + * This function should be called by the last man, after local CPU teardown + * is complete. CPU cache expected to be active. + * + * Returns: + * false: the critical section was not entered because an inbound CPU was + * observed, or the cluster is already being set up; + * true: the critical section was entered: it is now safe to tear down the + * cluster. + */ +bool __mcpm_outbound_enter_critical(unsigned int cpu, unsigned int cluster) +{ + unsigned int i; + struct mcpm_sync_struct *c = &mcpm_sync.clusters[cluster]; + + /* Warn inbound CPUs that the cluster is being torn down: */ + c->cluster = CLUSTER_GOING_DOWN; + sync_cache_w(&c->cluster); + + /* Back out if the inbound cluster is already in the critical region: */ + sync_cache_r(&c->inbound); + if (c->inbound == INBOUND_COMING_UP) + goto abort; + + /* + * Wait for all CPUs to get out of the GOING_DOWN state, so that local + * teardown is complete on each CPU before tearing down the cluster. + * + * If any CPU has been woken up again from the DOWN state, then we + * shouldn't be taking the cluster down at all: abort in that case. + */ + sync_cache_r(&c->cpus); + for (i = 0; i < MAX_CPUS_PER_CLUSTER; i++) { + int cpustate; + + if (i == cpu) + continue; + + while (1) { + cpustate = c->cpus[i].cpu; + if (cpustate != CPU_GOING_DOWN) + break; + + wfe(); + sync_cache_r(&c->cpus[i].cpu); + } + + switch (cpustate) { + case CPU_DOWN: + continue; + + default: + goto abort; + } + } + + return true; + +abort: + __mcpm_outbound_leave_critical(cluster, CLUSTER_UP); + return false; +} + +int __mcpm_cluster_state(unsigned int cluster) +{ + sync_cache_r(&mcpm_sync.clusters[cluster].cluster); + return mcpm_sync.clusters[cluster].cluster; +} + +extern unsigned long mcpm_power_up_setup_phys; + +int __init mcpm_sync_init( + void (*power_up_setup)(unsigned int affinity_level)) +{ + unsigned int i, j, mpidr, this_cluster; + + BUILD_BUG_ON(MCPM_SYNC_CLUSTER_SIZE * MAX_NR_CLUSTERS != sizeof mcpm_sync); + BUG_ON((unsigned long)&mcpm_sync & (__CACHE_WRITEBACK_GRANULE - 1)); + + /* + * Set initial CPU and cluster states. + * Only one cluster is assumed to be active at this point. + */ + for (i = 0; i < MAX_NR_CLUSTERS; i++) { + mcpm_sync.clusters[i].cluster = CLUSTER_DOWN; + mcpm_sync.clusters[i].inbound = INBOUND_NOT_COMING_UP; + for (j = 0; j < MAX_CPUS_PER_CLUSTER; j++) + mcpm_sync.clusters[i].cpus[j].cpu = CPU_DOWN; + } + mpidr = read_cpuid_mpidr(); + this_cluster = MPIDR_AFFINITY_LEVEL(mpidr, 1); + for_each_online_cpu(i) { + mcpm_cpu_use_count[this_cluster][i] = 1; + mcpm_sync.clusters[this_cluster].cpus[i].cpu = CPU_UP; + } + mcpm_sync.clusters[this_cluster].cluster = CLUSTER_UP; + sync_cache_w(&mcpm_sync); + + if (power_up_setup) { + mcpm_power_up_setup_phys = virt_to_phys(power_up_setup); + sync_cache_w(&mcpm_power_up_setup_phys); + } + + return 0; +} -- cgit v1.2.3-54-g00ecf