diff options
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/power/Kconfig | 11 | ||||
| -rw-r--r-- | kernel/power/qos.c | 106 | ||||
| -rw-r--r-- | kernel/sched/idle.c | 12 |
3 files changed, 124 insertions, 5 deletions
diff --git a/kernel/power/Kconfig b/kernel/power/Kconfig index 54a623680019..05337f437cca 100644 --- a/kernel/power/Kconfig +++ b/kernel/power/Kconfig @@ -202,6 +202,17 @@ config PM_WAKELOCKS_GC depends on PM_WAKELOCKS default y +config PM_QOS_CPU_SYSTEM_WAKEUP + bool "User space interface for CPU system wakeup QoS" + depends on CPU_IDLE + help + Enable this to allow user space via the cpu_wakeup_latency file to + specify a CPU system wakeup latency limit. + + This may be particularly useful for platforms supporting multiple low + power states for CPUs during system-wide suspend and s2idle in + particular. + config PM bool "Device power management core functionality" help diff --git a/kernel/power/qos.c b/kernel/power/qos.c index 4244b069442e..f7d8064e9adc 100644 --- a/kernel/power/qos.c +++ b/kernel/power/qos.c @@ -415,6 +415,105 @@ static struct miscdevice cpu_latency_qos_miscdev = { .fops = &cpu_latency_qos_fops, }; +#ifdef CONFIG_PM_QOS_CPU_SYSTEM_WAKEUP +/* The CPU system wakeup latency QoS. */ +static struct pm_qos_constraints cpu_wakeup_latency_constraints = { + .list = PLIST_HEAD_INIT(cpu_wakeup_latency_constraints.list), + .target_value = PM_QOS_RESUME_LATENCY_NO_CONSTRAINT, + .default_value = PM_QOS_RESUME_LATENCY_NO_CONSTRAINT, + .no_constraint_value = PM_QOS_RESUME_LATENCY_NO_CONSTRAINT, + .type = PM_QOS_MIN, +}; + +/** + * cpu_wakeup_latency_qos_limit - Current CPU system wakeup latency QoS limit. + * + * Returns the current CPU system wakeup latency QoS limit that may have been + * requested by user space. + */ +s32 cpu_wakeup_latency_qos_limit(void) +{ + return pm_qos_read_value(&cpu_wakeup_latency_constraints); +} + +static int cpu_wakeup_latency_qos_open(struct inode *inode, struct file *filp) +{ + struct pm_qos_request *req; + + req = kzalloc(sizeof(*req), GFP_KERNEL); + if (!req) + return -ENOMEM; + + req->qos = &cpu_wakeup_latency_constraints; + pm_qos_update_target(req->qos, &req->node, PM_QOS_ADD_REQ, + PM_QOS_RESUME_LATENCY_NO_CONSTRAINT); + filp->private_data = req; + + return 0; +} + +static int cpu_wakeup_latency_qos_release(struct inode *inode, + struct file *filp) +{ + struct pm_qos_request *req = filp->private_data; + + filp->private_data = NULL; + pm_qos_update_target(req->qos, &req->node, PM_QOS_REMOVE_REQ, + PM_QOS_RESUME_LATENCY_NO_CONSTRAINT); + kfree(req); + + return 0; +} + +static ssize_t cpu_wakeup_latency_qos_read(struct file *filp, char __user *buf, + size_t count, loff_t *f_pos) +{ + s32 value = pm_qos_read_value(&cpu_wakeup_latency_constraints); + + return simple_read_from_buffer(buf, count, f_pos, &value, sizeof(s32)); +} + +static ssize_t cpu_wakeup_latency_qos_write(struct file *filp, + const char __user *buf, + size_t count, loff_t *f_pos) +{ + struct pm_qos_request *req = filp->private_data; + s32 value; + + if (count == sizeof(s32)) { + if (copy_from_user(&value, buf, sizeof(s32))) + return -EFAULT; + } else { + int ret; + + ret = kstrtos32_from_user(buf, count, 16, &value); + if (ret) + return ret; + } + + if (value < 0) + return -EINVAL; + + pm_qos_update_target(req->qos, &req->node, PM_QOS_UPDATE_REQ, value); + + return count; +} + +static const struct file_operations cpu_wakeup_latency_qos_fops = { + .open = cpu_wakeup_latency_qos_open, + .release = cpu_wakeup_latency_qos_release, + .read = cpu_wakeup_latency_qos_read, + .write = cpu_wakeup_latency_qos_write, + .llseek = noop_llseek, +}; + +static struct miscdevice cpu_wakeup_latency_qos_miscdev = { + .minor = MISC_DYNAMIC_MINOR, + .name = "cpu_wakeup_latency", + .fops = &cpu_wakeup_latency_qos_fops, +}; +#endif /* CONFIG_PM_QOS_CPU_SYSTEM_WAKEUP */ + static int __init cpu_latency_qos_init(void) { int ret; @@ -424,6 +523,13 @@ static int __init cpu_latency_qos_init(void) pr_err("%s: %s setup failed\n", __func__, cpu_latency_qos_miscdev.name); +#ifdef CONFIG_PM_QOS_CPU_SYSTEM_WAKEUP + ret = misc_register(&cpu_wakeup_latency_qos_miscdev); + if (ret < 0) + pr_err("%s: %s setup failed\n", __func__, + cpu_wakeup_latency_qos_miscdev.name); +#endif + return ret; } late_initcall(cpu_latency_qos_init); diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c index c39b089d4f09..c1c3d0166610 100644 --- a/kernel/sched/idle.c +++ b/kernel/sched/idle.c @@ -131,12 +131,13 @@ void __cpuidle default_idle_call(void) } static int call_cpuidle_s2idle(struct cpuidle_driver *drv, - struct cpuidle_device *dev) + struct cpuidle_device *dev, + u64 max_latency_ns) { if (current_clr_polling_and_test()) return -EBUSY; - return cpuidle_enter_s2idle(drv, dev); + return cpuidle_enter_s2idle(drv, dev, max_latency_ns); } static int call_cpuidle(struct cpuidle_driver *drv, struct cpuidle_device *dev, @@ -205,12 +206,13 @@ static void cpuidle_idle_call(void) u64 max_latency_ns; if (idle_should_enter_s2idle()) { + max_latency_ns = cpu_wakeup_latency_qos_limit() * + NSEC_PER_USEC; - entered_state = call_cpuidle_s2idle(drv, dev); + entered_state = call_cpuidle_s2idle(drv, dev, + max_latency_ns); if (entered_state > 0) goto exit_idle; - - max_latency_ns = U64_MAX; } else { max_latency_ns = dev->forced_idle_latency_limit_ns; } |