diff options
Diffstat (limited to 'drivers/cpuidle')
| -rw-r--r-- | drivers/cpuidle/Kconfig | 3 | ||||
| -rw-r--r-- | drivers/cpuidle/Makefile | 1 | ||||
| -rw-r--r-- | drivers/cpuidle/dt_idle_states.c | 213 | ||||
| -rw-r--r-- | drivers/cpuidle/dt_idle_states.h | 7 |
4 files changed, 224 insertions, 0 deletions
diff --git a/drivers/cpuidle/Kconfig b/drivers/cpuidle/Kconfig index 32748c36c477..8deb934c6356 100644 --- a/drivers/cpuidle/Kconfig +++ b/drivers/cpuidle/Kconfig @@ -25,6 +25,9 @@ config CPU_IDLE_GOV_MENU bool "Menu governor (for tickless system)" default y +config DT_IDLE_STATES + bool + menu "ARM CPU Idle Drivers" depends on ARM source "drivers/cpuidle/Kconfig.arm" diff --git a/drivers/cpuidle/Makefile b/drivers/cpuidle/Makefile index 11edb31c55e9..002b65336ba9 100644 --- a/drivers/cpuidle/Makefile +++ b/drivers/cpuidle/Makefile @@ -4,6 +4,7 @@ obj-y += cpuidle.o driver.o governor.o sysfs.o governors/ obj-$(CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED) += coupled.o +obj-$(CONFIG_DT_IDLE_STATES) += dt_idle_states.o ################################################################################## # ARM SoC drivers diff --git a/drivers/cpuidle/dt_idle_states.c b/drivers/cpuidle/dt_idle_states.c new file mode 100644 index 000000000000..52f4d11bbf3f --- /dev/null +++ b/drivers/cpuidle/dt_idle_states.c @@ -0,0 +1,213 @@ +/* + * DT idle states parsing code. + * + * Copyright (C) 2014 ARM Ltd. + * Author: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> + * + * 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. + */ + +#define pr_fmt(fmt) "DT idle-states: " fmt + +#include <linux/cpuidle.h> +#include <linux/cpumask.h> +#include <linux/errno.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/of_device.h> + +#include "dt_idle_states.h" + +static int init_state_node(struct cpuidle_state *idle_state, + const struct of_device_id *matches, + struct device_node *state_node) +{ + int err; + const struct of_device_id *match_id; + + match_id = of_match_node(matches, state_node); + if (!match_id) + return -ENODEV; + /* + * CPUidle drivers are expected to initialize the const void *data + * pointer of the passed in struct of_device_id array to the idle + * state enter function. + */ + idle_state->enter = match_id->data; + + err = of_property_read_u32(state_node, "wakeup-latency-us", + &idle_state->exit_latency); + if (err) { + u32 entry_latency, exit_latency; + + err = of_property_read_u32(state_node, "entry-latency-us", + &entry_latency); + if (err) { + pr_debug(" * %s missing entry-latency-us property\n", + state_node->full_name); + return -EINVAL; + } + + err = of_property_read_u32(state_node, "exit-latency-us", + &exit_latency); + if (err) { + pr_debug(" * %s missing exit-latency-us property\n", + state_node->full_name); + return -EINVAL; + } + /* + * If wakeup-latency-us is missing, default to entry+exit + * latencies as defined in idle states bindings + */ + idle_state->exit_latency = entry_latency + exit_latency; + } + + err = of_property_read_u32(state_node, "min-residency-us", + &idle_state->target_residency); + if (err) { + pr_debug(" * %s missing min-residency-us property\n", + state_node->full_name); + return -EINVAL; + } + + idle_state->flags = CPUIDLE_FLAG_TIME_VALID; + if (of_property_read_bool(state_node, "local-timer-stop")) + idle_state->flags |= CPUIDLE_FLAG_TIMER_STOP; + /* + * TODO: + * replace with kstrdup and pointer assignment when name + * and desc become string pointers + */ + strncpy(idle_state->name, state_node->name, CPUIDLE_NAME_LEN - 1); + strncpy(idle_state->desc, state_node->name, CPUIDLE_DESC_LEN - 1); + return 0; +} + +/* + * Check that the idle state is uniform across all CPUs in the CPUidle driver + * cpumask + */ +static bool idle_state_valid(struct device_node *state_node, unsigned int idx, + const cpumask_t *cpumask) +{ + int cpu; + struct device_node *cpu_node, *curr_state_node; + bool valid = true; + + /* + * Compare idle state phandles for index idx on all CPUs in the + * CPUidle driver cpumask. Start from next logical cpu following + * cpumask_first(cpumask) since that's the CPU state_node was + * retrieved from. If a mismatch is found bail out straight + * away since we certainly hit a firmware misconfiguration. + */ + for (cpu = cpumask_next(cpumask_first(cpumask), cpumask); + cpu < nr_cpu_ids; cpu = cpumask_next(cpu, cpumask)) { + cpu_node = of_cpu_device_node_get(cpu); + curr_state_node = of_parse_phandle(cpu_node, "cpu-idle-states", + idx); + if (state_node != curr_state_node) + valid = false; + + of_node_put(curr_state_node); + of_node_put(cpu_node); + if (!valid) + break; + } + + return valid; +} + +/** + * dt_init_idle_driver() - Parse the DT idle states and initialize the + * idle driver states array + * @drv: Pointer to CPU idle driver to be initialized + * @matches: Array of of_device_id match structures to search in for + * compatible idle state nodes. The data pointer for each valid + * struct of_device_id entry in the matches array must point to + * a function with the following signature, that corresponds to + * the CPUidle state enter function signature: + * + * int (*)(struct cpuidle_device *dev, + * struct cpuidle_driver *drv, + * int index); + * + * @start_idx: First idle state index to be initialized + * + * If DT idle states are detected and are valid the state count and states + * array entries in the cpuidle driver are initialized accordingly starting + * from index start_idx. + * + * Return: number of valid DT idle states parsed, <0 on failure + */ +int dt_init_idle_driver(struct cpuidle_driver *drv, + const struct of_device_id *matches, + unsigned int start_idx) +{ + struct cpuidle_state *idle_state; + struct device_node *state_node, *cpu_node; + int i, err = 0; + const cpumask_t *cpumask; + unsigned int state_idx = start_idx; + + if (state_idx >= CPUIDLE_STATE_MAX) + return -EINVAL; + /* + * We get the idle states for the first logical cpu in the + * driver mask (or cpu_possible_mask if the driver cpumask is not set) + * and we check through idle_state_valid() if they are uniform + * across CPUs, otherwise we hit a firmware misconfiguration. + */ + cpumask = drv->cpumask ? : cpu_possible_mask; + cpu_node = of_cpu_device_node_get(cpumask_first(cpumask)); + + for (i = 0; ; i++) { + state_node = of_parse_phandle(cpu_node, "cpu-idle-states", i); + if (!state_node) + break; + + if (!idle_state_valid(state_node, i, cpumask)) { + pr_warn("%s idle state not valid, bailing out\n", + state_node->full_name); + err = -EINVAL; + break; + } + + if (state_idx == CPUIDLE_STATE_MAX) { + pr_warn("State index reached static CPU idle driver states array size\n"); + break; + } + + idle_state = &drv->states[state_idx++]; + err = init_state_node(idle_state, matches, state_node); + if (err) { + pr_err("Parsing idle state node %s failed with err %d\n", + state_node->full_name, err); + err = -EINVAL; + break; + } + of_node_put(state_node); + } + + of_node_put(state_node); + of_node_put(cpu_node); + if (err) + return err; + /* + * Update the driver state count only if some valid DT idle states + * were detected + */ + if (i) + drv->state_count = state_idx; + + /* + * Return the number of present and valid DT idle states, which can + * also be 0 on platforms with missing DT idle states or legacy DT + * configuration predating the DT idle states bindings. + */ + return i; +} +EXPORT_SYMBOL_GPL(dt_init_idle_driver); diff --git a/drivers/cpuidle/dt_idle_states.h b/drivers/cpuidle/dt_idle_states.h new file mode 100644 index 000000000000..4818134bc65b --- /dev/null +++ b/drivers/cpuidle/dt_idle_states.h @@ -0,0 +1,7 @@ +#ifndef __DT_IDLE_STATES +#define __DT_IDLE_STATES + +int dt_init_idle_driver(struct cpuidle_driver *drv, + const struct of_device_id *matches, + unsigned int start_idx); +#endif |