diff options
Diffstat (limited to 'arch/arm')
| -rw-r--r-- | arch/arm/common/mcpm_entry.c | 202 | ||||
| -rw-r--r-- | arch/arm/include/asm/mcpm.h | 65 |
2 files changed, 233 insertions, 34 deletions
diff --git a/arch/arm/common/mcpm_entry.c b/arch/arm/common/mcpm_entry.c index 3c165fc2dce2..5f8a52ac7edf 100644 --- a/arch/arm/common/mcpm_entry.c +++ b/arch/arm/common/mcpm_entry.c @@ -55,22 +55,81 @@ 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(); - return platform_ops->power_up(cpu, cluster); + + /* 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 || !platform_ops->power_down)) - return; + if (WARN_ON_ONCE(!platform_ops)) + return; BUG_ON(!irqs_disabled()); /* @@ -79,28 +138,65 @@ void mcpm_cpu_power_down(void) */ setup_mm_for_reboot(); - platform_ops->power_down(); + /* 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 - * power_down method might not be able to actually enter a - * powered down state with the WFI instruction if the power_up - * method has removed the required reset condition. The - * power_down method is then allowed to return. We must perform - * a re-entry in the kernel as if the power_up method just had - * deasserted reset on the CPU. - * - * To simplify race issues, the platform specific implementation - * must accommodate for the possibility of unordered calls to - * power_down and power_up with a usage count. Therefore, if a - * call to power_up is issued for a CPU that is not down, then - * the next call to power_down must not attempt a full shutdown - * but only do the minimum (normally disabling L1 cache and CPU - * coherency) and return just as if a concurrent power_up request - * had happened as described above. + * 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)); @@ -125,26 +221,66 @@ int mcpm_wait_for_cpu_powerdown(unsigned int cpu, unsigned int cluster) void mcpm_cpu_suspend(u64 expected_residency) { - phys_reset_t phys_reset; - - if (WARN_ON_ONCE(!platform_ops || !platform_ops->suspend)) + if (WARN_ON_ONCE(!platform_ops)) return; - BUG_ON(!irqs_disabled()); - /* Very similar to mcpm_cpu_power_down() */ - 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(); + /* 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; - if (platform_ops->powered_up) + + /* 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; } @@ -334,8 +470,10 @@ int __init mcpm_sync_init( } mpidr = read_cpuid_mpidr(); this_cluster = MPIDR_AFFINITY_LEVEL(mpidr, 1); - for_each_online_cpu(i) + 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); diff --git a/arch/arm/include/asm/mcpm.h b/arch/arm/include/asm/mcpm.h index 3446f6a1d9fa..50b378f59e08 100644 --- a/arch/arm/include/asm/mcpm.h +++ b/arch/arm/include/asm/mcpm.h @@ -171,12 +171,73 @@ void mcpm_cpu_suspend(u64 expected_residency); int mcpm_cpu_powered_up(void); /* - * Platform specific methods used in the implementation of the above API. + * Platform specific callbacks used in the implementation of the above API. + * + * cpu_powerup: + * Make given CPU runable. Called with MCPM lock held and IRQs disabled. + * The given cluster is assumed to be set up (cluster_powerup would have + * been called beforehand). Must return 0 for success or negative error code. + * + * cluster_powerup: + * Set up power for given cluster. Called with MCPM lock held and IRQs + * disabled. Called before first cpu_powerup when cluster is down. Must + * return 0 for success or negative error code. + * + * cpu_suspend_prepare: + * Special suspend configuration. Called on target CPU with MCPM lock held + * and IRQs disabled. This callback is optional. If provided, it is called + * before cpu_powerdown_prepare. + * + * cpu_powerdown_prepare: + * Configure given CPU for power down. Called on target CPU with MCPM lock + * held and IRQs disabled. Power down must be effective only at the next WFI instruction. + * + * cluster_powerdown_prepare: + * Configure given cluster for power down. Called on one CPU from target + * cluster with MCPM lock held and IRQs disabled. A cpu_powerdown_prepare + * for each CPU in the cluster has happened when this occurs. + * + * cpu_cache_disable: + * Clean and disable CPU level cache for the calling CPU. Called on with IRQs + * disabled only. The CPU is no longer cache coherent with the rest of the + * system when this returns. + * + * cluster_cache_disable: + * Clean and disable the cluster wide cache as well as the CPU level cache + * for the calling CPU. No call to cpu_cache_disable will happen for this + * CPU. Called with IRQs disabled and only when all the other CPUs are done + * with their own cpu_cache_disable. The cluster is no longer cache coherent + * with the rest of the system when this returns. + * + * cpu_is_up: + * Called on given CPU after it has been powered up or resumed. The MCPM lock + * is held and IRQs disabled. This callback is optional. + * + * cluster_is_up: + * Called by the first CPU to be powered up or resumed in given cluster. + * The MCPM lock is held and IRQs disabled. This callback is optional. If + * provided, it is called before cpu_is_up for that CPU. + * + * wait_for_powerdown: + * Wait until given CPU is powered down. This is called in sleeping context. + * Some reasonable timeout must be considered. Must return 0 for success or + * negative error code. */ struct mcpm_platform_ops { + int (*cpu_powerup)(unsigned int cpu, unsigned int cluster); + int (*cluster_powerup)(unsigned int cluster); + void (*cpu_suspend_prepare)(unsigned int cpu, unsigned int cluster); + void (*cpu_powerdown_prepare)(unsigned int cpu, unsigned int cluster); + void (*cluster_powerdown_prepare)(unsigned int cluster); + void (*cpu_cache_disable)(void); + void (*cluster_cache_disable)(void); + void (*cpu_is_up)(unsigned int cpu, unsigned int cluster); + void (*cluster_is_up)(unsigned int cluster); + int (*wait_for_powerdown)(unsigned int cpu, unsigned int cluster); + + /* deprecated callbacks */ int (*power_up)(unsigned int cpu, unsigned int cluster); void (*power_down)(void); - int (*wait_for_powerdown)(unsigned int cpu, unsigned int cluster); void (*suspend)(u64); void (*powered_up)(void); }; |