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12bb3440 SG |
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> | |
e5f9dec8 | 12 | #include <asm/proc-fns.h> |
12bb3440 | 13 | |
e5f9dec8 | 14 | #include "common.h" |
12bb3440 SG |
15 | #include "cpuidle.h" |
16 | ||
e5f9dec8 SG |
17 | static atomic_t master = ATOMIC_INIT(0); |
18 | static DEFINE_SPINLOCK(master_lock); | |
19 | ||
20 | static int imx6q_enter_wait(struct cpuidle_device *dev, | |
21 | struct cpuidle_driver *drv, int index) | |
22 | { | |
e5f9dec8 SG |
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 | imx6q_set_lpm(WAIT_UNCLOCKED); | |
31 | cpu_do_idle(); | |
32 | imx6q_set_lpm(WAIT_CLOCKED); | |
33 | spin_unlock(&master_lock); | |
34 | goto done; | |
35 | } | |
36 | ||
37 | idle: | |
38 | cpu_do_idle(); | |
39 | done: | |
40 | atomic_dec(&master); | |
e5f9dec8 SG |
41 | |
42 | return index; | |
43 | } | |
44 | ||
12bb3440 SG |
45 | static struct cpuidle_driver imx6q_cpuidle_driver = { |
46 | .name = "imx6q_cpuidle", | |
47 | .owner = THIS_MODULE, | |
e5f9dec8 SG |
48 | .states = { |
49 | /* WFI */ | |
50 | ARM_CPUIDLE_WFI_STATE, | |
51 | /* WAIT */ | |
52 | { | |
53 | .exit_latency = 50, | |
54 | .target_residency = 75, | |
8de46eff DL |
55 | .flags = CPUIDLE_FLAG_TIME_VALID | |
56 | CPUIDLE_FLAG_TIMER_STOP, | |
e5f9dec8 SG |
57 | .enter = imx6q_enter_wait, |
58 | .name = "WAIT", | |
59 | .desc = "Clock off", | |
60 | }, | |
61 | }, | |
62 | .state_count = 2, | |
63 | .safe_state_index = 0, | |
12bb3440 SG |
64 | }; |
65 | ||
66 | int __init imx6q_cpuidle_init(void) | |
67 | { | |
e5f9dec8 SG |
68 | /* Need to enable SCU standby for entering WAIT modes */ |
69 | imx_scu_standby_enable(); | |
70 | ||
71 | /* Set chicken bit to get a reliable WAIT mode support */ | |
72 | imx6q_set_chicken_bit(); | |
73 | ||
54a4644b | 74 | return cpuidle_register(&imx6q_cpuidle_driver, NULL); |
12bb3440 | 75 | } |