diff options
Diffstat (limited to 'drivers/cpuidle/cpuidle-psci.c')
| -rw-r--r-- | drivers/cpuidle/cpuidle-psci.c | 236 |
1 files changed, 236 insertions, 0 deletions
diff --git a/drivers/cpuidle/cpuidle-psci.c b/drivers/cpuidle/cpuidle-psci.c new file mode 100644 index 000000000000..f3c1a2396f98 --- /dev/null +++ b/drivers/cpuidle/cpuidle-psci.c @@ -0,0 +1,236 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * PSCI CPU idle driver. + * + * Copyright (C) 2019 ARM Ltd. + * Author: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> + */ + +#define pr_fmt(fmt) "CPUidle PSCI: " fmt + +#include <linux/cpuidle.h> +#include <linux/cpumask.h> +#include <linux/cpu_pm.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/of_device.h> +#include <linux/psci.h> +#include <linux/slab.h> + +#include <asm/cpuidle.h> + +#include "dt_idle_states.h" + +static DEFINE_PER_CPU_READ_MOSTLY(u32 *, psci_power_state); + +static int psci_enter_idle_state(struct cpuidle_device *dev, + struct cpuidle_driver *drv, int idx) +{ + u32 *state = __this_cpu_read(psci_power_state); + + return CPU_PM_CPU_IDLE_ENTER_PARAM(psci_cpu_suspend_enter, + idx, state[idx - 1]); +} + +static struct cpuidle_driver psci_idle_driver __initdata = { + .name = "psci_idle", + .owner = THIS_MODULE, + /* + * PSCI idle states relies on architectural WFI to + * be represented as state index 0. + */ + .states[0] = { + .enter = psci_enter_idle_state, + .exit_latency = 1, + .target_residency = 1, + .power_usage = UINT_MAX, + .name = "WFI", + .desc = "ARM WFI", + } +}; + +static const struct of_device_id psci_idle_state_match[] __initconst = { + { .compatible = "arm,idle-state", + .data = psci_enter_idle_state }, + { }, +}; + +static int __init psci_dt_parse_state_node(struct device_node *np, u32 *state) +{ + int err = of_property_read_u32(np, "arm,psci-suspend-param", state); + + if (err) { + pr_warn("%pOF missing arm,psci-suspend-param property\n", np); + return err; + } + + if (!psci_power_state_is_valid(*state)) { + pr_warn("Invalid PSCI power state %#x\n", *state); + return -EINVAL; + } + + return 0; +} + +static int __init psci_dt_cpu_init_idle(struct device_node *cpu_node, int cpu) +{ + int i, ret = 0, count = 0; + u32 *psci_states; + struct device_node *state_node; + + /* Count idle states */ + while ((state_node = of_parse_phandle(cpu_node, "cpu-idle-states", + count))) { + count++; + of_node_put(state_node); + } + + if (!count) + return -ENODEV; + + psci_states = kcalloc(count, sizeof(*psci_states), GFP_KERNEL); + if (!psci_states) + return -ENOMEM; + + for (i = 0; i < count; i++) { + state_node = of_parse_phandle(cpu_node, "cpu-idle-states", i); + ret = psci_dt_parse_state_node(state_node, &psci_states[i]); + of_node_put(state_node); + + if (ret) + goto free_mem; + + pr_debug("psci-power-state %#x index %d\n", psci_states[i], i); + } + + /* Idle states parsed correctly, initialize per-cpu pointer */ + per_cpu(psci_power_state, cpu) = psci_states; + return 0; + +free_mem: + kfree(psci_states); + return ret; +} + +static __init int psci_cpu_init_idle(unsigned int cpu) +{ + struct device_node *cpu_node; + int ret; + + /* + * If the PSCI cpu_suspend function hook has not been initialized + * idle states must not be enabled, so bail out + */ + if (!psci_ops.cpu_suspend) + return -EOPNOTSUPP; + + cpu_node = of_cpu_device_node_get(cpu); + if (!cpu_node) + return -ENODEV; + + ret = psci_dt_cpu_init_idle(cpu_node, cpu); + + of_node_put(cpu_node); + + return ret; +} + +static int __init psci_idle_init_cpu(int cpu) +{ + struct cpuidle_driver *drv; + struct device_node *cpu_node; + const char *enable_method; + int ret = 0; + + cpu_node = of_cpu_device_node_get(cpu); + if (!cpu_node) + return -ENODEV; + + /* + * Check whether the enable-method for the cpu is PSCI, fail + * if it is not. + */ + enable_method = of_get_property(cpu_node, "enable-method", NULL); + if (!enable_method || (strcmp(enable_method, "psci"))) + ret = -ENODEV; + + of_node_put(cpu_node); + if (ret) + return ret; + + drv = kmemdup(&psci_idle_driver, sizeof(*drv), GFP_KERNEL); + if (!drv) + return -ENOMEM; + + drv->cpumask = (struct cpumask *)cpumask_of(cpu); + + /* + * Initialize idle states data, starting at index 1, since + * by default idle state 0 is the quiescent state reached + * by the cpu by executing the wfi instruction. + * + * If no DT idle states are detected (ret == 0) let the driver + * initialization fail accordingly since there is no reason to + * initialize the idle driver if only wfi is supported, the + * default archictectural back-end already executes wfi + * on idle entry. + */ + ret = dt_init_idle_driver(drv, psci_idle_state_match, 1); + if (ret <= 0) { + ret = ret ? : -ENODEV; + goto out_kfree_drv; + } + + /* + * Initialize PSCI idle states. + */ + ret = psci_cpu_init_idle(cpu); + if (ret) { + pr_err("CPU %d failed to PSCI idle\n", cpu); + goto out_kfree_drv; + } + + ret = cpuidle_register(drv, NULL); + if (ret) + goto out_kfree_drv; + + return 0; + +out_kfree_drv: + kfree(drv); + return ret; +} + +/* + * psci_idle_init - Initializes PSCI cpuidle driver + * + * Initializes PSCI cpuidle driver for all CPUs, if any CPU fails + * to register cpuidle driver then rollback to cancel all CPUs + * registration. + */ +static int __init psci_idle_init(void) +{ + int cpu, ret; + struct cpuidle_driver *drv; + struct cpuidle_device *dev; + + for_each_possible_cpu(cpu) { + ret = psci_idle_init_cpu(cpu); + if (ret) + goto out_fail; + } + + return 0; + +out_fail: + while (--cpu >= 0) { + dev = per_cpu(cpuidle_devices, cpu); + drv = cpuidle_get_cpu_driver(dev); + cpuidle_unregister(drv); + kfree(drv); + } + + return ret; +} +device_initcall(psci_idle_init); |