+++ /dev/null
-/*
- * OF 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.
- */
-
-#include <linux/cpuidle.h>
-#include <linux/cpumask.h>
-#include <linux/errno.h>
-#include <linux/kernel.h>
-#include <linux/list.h>
-#include <linux/list_sort.h>
-#include <linux/module.h>
-#include <linux/of.h>
-#include <linux/slab.h>
-
-#include "of_idle_states.h"
-
-struct state_elem {
- struct list_head list;
- struct device_node *node;
- int val;
-};
-
-static struct list_head head __initdata = LIST_HEAD_INIT(head);
-
-static bool __init state_cpu_valid(struct device_node *state_node,
- struct device_node *cpu_node)
-{
- int i = 0;
- struct device_node *cpu_state;
-
- while ((cpu_state = of_parse_phandle(cpu_node,
- "cpu-idle-states", i++))) {
- if (cpu_state && state_node == cpu_state) {
- of_node_put(cpu_state);
- return true;
- }
- of_node_put(cpu_state);
- }
- return false;
-}
-
-static bool __init state_cpus_valid(const cpumask_t *cpus,
- struct device_node *state_node)
-{
- int cpu;
- struct device_node *cpu_node;
-
- /*
- * Check if state is valid on driver cpumask cpus
- */
- for_each_cpu(cpu, cpus) {
- cpu_node = of_get_cpu_node(cpu, NULL);
-
- if (!cpu_node) {
- pr_err("Missing device node for CPU %d\n", cpu);
- return false;
- }
-
- if (!state_cpu_valid(state_node, cpu_node))
- return false;
- }
-
- return true;
-}
-
-static int __init state_cmp(void *priv, struct list_head *a,
- struct list_head *b)
-{
- struct state_elem *ela, *elb;
-
- ela = container_of(a, struct state_elem, list);
- elb = container_of(b, struct state_elem, list);
-
- return ela->val - elb->val;
-}
-
-static int __init add_state_node(cpumask_t *cpumask,
- struct device_node *state_node)
-{
- struct state_elem *el;
- u32 val;
-
- pr_debug(" * %s...\n", state_node->full_name);
-
- if (!state_cpus_valid(cpumask, state_node))
- return -EINVAL;
- /*
- * Parse just the value required to sort the states.
- */
- if (of_property_read_u32(state_node, "min-residency-us",
- &val)) {
- pr_debug(" * %s missing min-residency-us property\n",
- state_node->full_name);
- return -EINVAL;
- }
-
- el = kmalloc(sizeof(*el), GFP_KERNEL);
- if (!el) {
- pr_err("%s failed to allocate memory\n", __func__);
- return -ENOMEM;
- }
-
- el->node = state_node;
- el->val = val;
- list_add_tail(&el->list, &head);
-
- return 0;
-}
-
-static void __init init_state_node(struct cpuidle_driver *drv,
- struct device_node *state_node,
- int *cnt)
-{
- struct cpuidle_state *idle_state;
-
- pr_debug(" * %s...\n", state_node->full_name);
-
- idle_state = &drv->states[*cnt];
-
- if (of_property_read_u32(state_node, "exit-latency-us",
- &idle_state->exit_latency)) {
- pr_debug(" * %s missing exit-latency-us property\n",
- state_node->full_name);
- return;
- }
-
- if (of_property_read_u32(state_node, "min-residency-us",
- &idle_state->target_residency)) {
- pr_debug(" * %s missing min-residency-us property\n",
- state_node->full_name);
- return;
- }
- /*
- * It is unknown to the idle driver if and when the tick_device
- * loses context when the CPU enters the idle states. To solve
- * this issue the tick device must be linked to a power domain
- * so that the idle driver can check on which states the device
- * loses its context. Current code takes the conservative choice
- * of defining the idle state as one where the tick device always
- * loses its context. On platforms where tick device never loses
- * its context (ie it is not a C3STOP device) this turns into
- * a nop. On platforms where the tick device does lose context in some
- * states, this code can be optimized, when power domain specifications
- * for ARM CPUs are finalized.
- */
- idle_state->flags = CPUIDLE_FLAG_TIME_VALID | CPUIDLE_FLAG_TIMER_STOP;
-
- strncpy(idle_state->name, state_node->name, CPUIDLE_NAME_LEN);
- strncpy(idle_state->desc, state_node->name, CPUIDLE_NAME_LEN);
-
- (*cnt)++;
-}
-
-static int __init init_idle_states(struct cpuidle_driver *drv,
- struct device_node *state_nodes[],
- unsigned int start_idx, bool init_nodes)
-{
- struct state_elem *el;
- struct list_head *curr, *tmp;
- unsigned int cnt = start_idx;
-
- list_for_each_entry(el, &head, list) {
- /*
- * Check if the init function has to fill the
- * state_nodes array on behalf of the CPUidle driver.
- */
- if (init_nodes)
- state_nodes[cnt] = el->node;
- /*
- * cnt is updated on return if a state was added.
- */
- init_state_node(drv, el->node, &cnt);
-
- if (cnt == CPUIDLE_STATE_MAX) {
- pr_warn("State index reached static CPU idle state limit\n");
- break;
- }
- }
-
- drv->state_count = cnt;
-
- list_for_each_safe(curr, tmp, &head) {
- list_del(curr);
- kfree(container_of(curr, struct state_elem, list));
- }
-
- /*
- * If no idle states are detected, return an error and let the idle
- * driver initialization fail accordingly.
- */
- return (cnt > start_idx) ? 0 : -ENODATA;
-}
-
-static void __init add_idle_states(struct cpuidle_driver *drv,
- struct device_node *idle_states)
-{
- struct device_node *state_node;
-
- for_each_child_of_node(idle_states, state_node) {
- if ((!of_device_is_compatible(state_node, "arm,idle-state"))) {
- pr_warn(" * %s: children of /cpus/idle-states must be \"arm,idle-state\" compatible\n",
- state_node->full_name);
- continue;
- }
- /*
- * If memory allocation fails, better bail out.
- * Initialized nodes are freed at initialization
- * completion in of_init_idle_driver().
- */
- if ((add_state_node(drv->cpumask, state_node) == -ENOMEM))
- break;
- }
- /*
- * Sort the states list before initializing the CPUidle driver
- * states array.
- */
- list_sort(NULL, &head, state_cmp);
-}
-
-/*
- * of_init_idle_driver - Parse the DT idle states and initialize the
- * idle driver states array
- *
- * @drv: Pointer to CPU idle driver to be initialized
- * @state_nodes: Array of struct device_nodes to be initialized if
- * init_nodes == true. Must be sized CPUIDLE_STATE_MAX
- * @start_idx: First idle state index to be initialized
- * @init_nodes: Boolean to request device nodes initialization
- *
- * Returns:
- * 0 on success
- * <0 on failure
- *
- * On success the states array in the cpuidle driver contains
- * initialized entries in the states array, starting from index start_idx.
- * If init_nodes == true, on success the state_nodes array is initialized
- * with idle state DT node pointers, starting from index start_idx,
- * in a 1:1 relation with the idle driver states array.
- */
-int __init of_init_idle_driver(struct cpuidle_driver *drv,
- struct device_node *state_nodes[],
- unsigned int start_idx, bool init_nodes)
-{
- struct device_node *idle_states_node;
- int ret;
-
- if (start_idx >= CPUIDLE_STATE_MAX) {
- pr_warn("State index exceeds static CPU idle driver states array size\n");
- return -EINVAL;
- }
-
- if (WARN(init_nodes && !state_nodes,
- "Requested nodes stashing in an invalid nodes container\n"))
- return -EINVAL;
-
- idle_states_node = of_find_node_by_path("/cpus/idle-states");
- if (!idle_states_node)
- return -ENOENT;
-
- add_idle_states(drv, idle_states_node);
-
- ret = init_idle_states(drv, state_nodes, start_idx, init_nodes);
-
- of_node_put(idle_states_node);
-
- return ret;
-}
projects / firefly-linux-kernel-4.4.55.git / commitdiff