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 <soc/imx/cpuidle.h>
14
15 #include "common.h"
16 #include "cpuidle.h"
17 #include "hardware.h"
18
19 static int num_idle_cpus = 0;
20 static DEFINE_SPINLOCK(cpuidle_lock);
21
imx6q_enter_wait(struct cpuidle_device * dev,struct cpuidle_driver * drv,int index)22 static int imx6q_enter_wait(struct cpuidle_device *dev,
23 struct cpuidle_driver *drv, int index)
24 {
25 spin_lock(&cpuidle_lock);
26 if (++num_idle_cpus == num_online_cpus())
27 imx6_set_lpm(WAIT_UNCLOCKED);
28 spin_unlock(&cpuidle_lock);
29
30 cpu_do_idle();
31
32 spin_lock(&cpuidle_lock);
33 if (num_idle_cpus-- == num_online_cpus())
34 imx6_set_lpm(WAIT_CLOCKED);
35 spin_unlock(&cpuidle_lock);
36
37 return index;
38 }
39
40 static struct cpuidle_driver imx6q_cpuidle_driver = {
41 .name = "imx6q_cpuidle",
42 .owner = THIS_MODULE,
43 .states = {
44 /* WFI */
45 ARM_CPUIDLE_WFI_STATE,
46 /* WAIT */
47 {
48 .exit_latency = 50,
49 .target_residency = 75,
50 .flags = CPUIDLE_FLAG_TIMER_STOP,
51 .enter = imx6q_enter_wait,
52 .name = "WAIT",
53 .desc = "Clock off",
54 },
55 },
56 .state_count = 2,
57 .safe_state_index = 0,
58 };
59
60 /*
61 * i.MX6 Q/DL has an erratum (ERR006687) that prevents the FEC from waking the
62 * CPUs when they are in wait(unclocked) state. As the hardware workaround isn't
63 * applicable to all boards, disable the deeper idle state when the workaround
64 * isn't present and the FEC is in use.
65 */
imx6q_cpuidle_fec_irqs_used(void)66 void imx6q_cpuidle_fec_irqs_used(void)
67 {
68 imx6q_cpuidle_driver.states[1].disabled = true;
69 }
70 EXPORT_SYMBOL_GPL(imx6q_cpuidle_fec_irqs_used);
71
imx6q_cpuidle_fec_irqs_unused(void)72 void imx6q_cpuidle_fec_irqs_unused(void)
73 {
74 imx6q_cpuidle_driver.states[1].disabled = false;
75 }
76 EXPORT_SYMBOL_GPL(imx6q_cpuidle_fec_irqs_unused);
77
imx6q_cpuidle_init(void)78 int __init imx6q_cpuidle_init(void)
79 {
80 /* Set INT_MEM_CLK_LPM bit to get a reliable WAIT mode support */
81 imx6_set_int_mem_clk_lpm(true);
82
83 return cpuidle_register(&imx6q_cpuidle_driver, NULL);
84 }
85