1/*
2 * Copyright (C) 2012 Freescale Semiconductor, Inc.
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation.
7 */
8
9#include <linux/cpuidle.h>
10#include <linux/module.h>
11#include <asm/cpuidle.h>
12
13#include "common.h"
14#include "cpuidle.h"
15#include "hardware.h"
16
17static atomic_t master = ATOMIC_INIT(0);
18static DEFINE_SPINLOCK(master_lock);
19
20static int imx6q_enter_wait(struct cpuidle_device *dev,
21			    struct cpuidle_driver *drv, int index)
22{
23	if (atomic_inc_return(&master) == num_online_cpus()) {
24		/*
25		 * With this lock, we prevent other cpu to exit and enter
26		 * this function again and become the master.
27		 */
28		if (!spin_trylock(&master_lock))
29			goto idle;
30		imx6_set_lpm(WAIT_UNCLOCKED);
31		cpu_do_idle();
32		imx6_set_lpm(WAIT_CLOCKED);
33		spin_unlock(&master_lock);
34		goto done;
35	}
36
37idle:
38	cpu_do_idle();
39done:
40	atomic_dec(&master);
41
42	return index;
43}
44
45static struct cpuidle_driver imx6q_cpuidle_driver = {
46	.name = "imx6q_cpuidle",
47	.owner = THIS_MODULE,
48	.states = {
49		/* WFI */
50		ARM_CPUIDLE_WFI_STATE,
51		/* WAIT */
52		{
53			.exit_latency = 50,
54			.target_residency = 75,
55			.flags = CPUIDLE_FLAG_TIMER_STOP,
56			.enter = imx6q_enter_wait,
57			.name = "WAIT",
58			.desc = "Clock off",
59		},
60	},
61	.state_count = 2,
62	.safe_state_index = 0,
63};
64
65int __init imx6q_cpuidle_init(void)
66{
67	/* Set INT_MEM_CLK_LPM bit to get a reliable WAIT mode support */
68	imx6q_set_int_mem_clk_lpm(true);
69
70	return cpuidle_register(&imx6q_cpuidle_driver, NULL);
71}
72