1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright (C) 2012 Freescale Semiconductor, Inc.
4 */
5
6 #include <linux/cpuidle.h>
7 #include <linux/module.h>
8 #include <asm/cpuidle.h>
9
10 #include <soc/imx/cpuidle.h>
11
12 #include "common.h"
13 #include "cpuidle.h"
14 #include "hardware.h"
15
16 static int num_idle_cpus = 0;
17 static DEFINE_RAW_SPINLOCK(cpuidle_lock);
18
imx6q_enter_wait(struct cpuidle_device * dev,struct cpuidle_driver * drv,int index)19 static int imx6q_enter_wait(struct cpuidle_device *dev,
20 struct cpuidle_driver *drv, int index)
21 {
22 raw_spin_lock(&cpuidle_lock);
23 if (++num_idle_cpus == num_online_cpus())
24 imx6_set_lpm(WAIT_UNCLOCKED);
25 raw_spin_unlock(&cpuidle_lock);
26
27 cpu_do_idle();
28
29 raw_spin_lock(&cpuidle_lock);
30 if (num_idle_cpus-- == num_online_cpus())
31 imx6_set_lpm(WAIT_CLOCKED);
32 raw_spin_unlock(&cpuidle_lock);
33
34 return index;
35 }
36
37 static struct cpuidle_driver imx6q_cpuidle_driver = {
38 .name = "imx6q_cpuidle",
39 .owner = THIS_MODULE,
40 .states = {
41 /* WFI */
42 ARM_CPUIDLE_WFI_STATE,
43 /* WAIT */
44 {
45 .exit_latency = 50,
46 .target_residency = 75,
47 .flags = CPUIDLE_FLAG_TIMER_STOP,
48 .enter = imx6q_enter_wait,
49 .name = "WAIT",
50 .desc = "Clock off",
51 },
52 },
53 .state_count = 2,
54 .safe_state_index = 0,
55 };
56
57 /*
58 * i.MX6 Q/DL has an erratum (ERR006687) that prevents the FEC from waking the
59 * CPUs when they are in wait(unclocked) state. As the hardware workaround isn't
60 * applicable to all boards, disable the deeper idle state when the workaround
61 * isn't present and the FEC is in use.
62 */
imx6q_cpuidle_fec_irqs_used(void)63 void imx6q_cpuidle_fec_irqs_used(void)
64 {
65 imx6q_cpuidle_driver.states[1].disabled = true;
66 }
67 EXPORT_SYMBOL_GPL(imx6q_cpuidle_fec_irqs_used);
68
imx6q_cpuidle_fec_irqs_unused(void)69 void imx6q_cpuidle_fec_irqs_unused(void)
70 {
71 imx6q_cpuidle_driver.states[1].disabled = false;
72 }
73 EXPORT_SYMBOL_GPL(imx6q_cpuidle_fec_irqs_unused);
74
imx6q_cpuidle_init(void)75 int __init imx6q_cpuidle_init(void)
76 {
77 /* Set INT_MEM_CLK_LPM bit to get a reliable WAIT mode support */
78 imx6_set_int_mem_clk_lpm(true);
79
80 return cpuidle_register(&imx6q_cpuidle_driver, NULL);
81 }
82