linux-imx

/*

 * 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 *match_id,

               struct device_node *state_node)

{

    int err;

    const char *desc;

​

    /*

     * 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;

    /*

     * Since this is not a "coupled" state, it's safe to assume interrupts

     * won't be enabled when it exits allowing the tick to be frozen

     * safely. So enter() can be also enter_s2idle() callback.

     */

    idle_state->enter_s2idle = 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(" * %pOF missing entry-latency-us property\n",

                 state_node);

            return -EINVAL;

        }

​

        err = of_property_read_u32(state_node, "exit-latency-us",

                       &exit_latency);

        if (err) {

            pr_debug(" * %pOF missing exit-latency-us property\n",

                 state_node);

            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(" * %pOF missing min-residency-us property\n",

                 state_node);

        return -EINVAL;

    }

​

    err = of_property_read_string(state_node, "idle-state-name", &desc);

    if (err)

        desc = state_node->name;

​

    idle_state->flags = 0;

    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, desc, CPUIDLE_DESC_LEN - 1);