1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0-only
2*4882a593Smuzhiyun /*
3*4882a593Smuzhiyun * Copyright (c) 2012 Linaro : Daniel Lezcano <daniel.lezcano@linaro.org> (IBM)
4*4882a593Smuzhiyun *
5*4882a593Smuzhiyun * Based on the work of Rickard Andersson <rickard.andersson@stericsson.com>
6*4882a593Smuzhiyun * and Jonas Aaberg <jonas.aberg@stericsson.com>.
7*4882a593Smuzhiyun */
8*4882a593Smuzhiyun
9*4882a593Smuzhiyun #include <linux/init.h>
10*4882a593Smuzhiyun #include <linux/cpuidle.h>
11*4882a593Smuzhiyun #include <linux/spinlock.h>
12*4882a593Smuzhiyun #include <linux/atomic.h>
13*4882a593Smuzhiyun #include <linux/smp.h>
14*4882a593Smuzhiyun #include <linux/mfd/dbx500-prcmu.h>
15*4882a593Smuzhiyun #include <linux/platform_data/arm-ux500-pm.h>
16*4882a593Smuzhiyun #include <linux/platform_device.h>
17*4882a593Smuzhiyun
18*4882a593Smuzhiyun #include <asm/cpuidle.h>
19*4882a593Smuzhiyun
20*4882a593Smuzhiyun static atomic_t master = ATOMIC_INIT(0);
21*4882a593Smuzhiyun static DEFINE_SPINLOCK(master_lock);
22*4882a593Smuzhiyun
ux500_enter_idle(struct cpuidle_device * dev,struct cpuidle_driver * drv,int index)23*4882a593Smuzhiyun static inline int ux500_enter_idle(struct cpuidle_device *dev,
24*4882a593Smuzhiyun struct cpuidle_driver *drv, int index)
25*4882a593Smuzhiyun {
26*4882a593Smuzhiyun int this_cpu = smp_processor_id();
27*4882a593Smuzhiyun bool recouple = false;
28*4882a593Smuzhiyun
29*4882a593Smuzhiyun if (atomic_inc_return(&master) == num_online_cpus()) {
30*4882a593Smuzhiyun
31*4882a593Smuzhiyun /* With this lock, we prevent the other cpu to exit and enter
32*4882a593Smuzhiyun * this function again and become the master */
33*4882a593Smuzhiyun if (!spin_trylock(&master_lock))
34*4882a593Smuzhiyun goto wfi;
35*4882a593Smuzhiyun
36*4882a593Smuzhiyun /* decouple the gic from the A9 cores */
37*4882a593Smuzhiyun if (prcmu_gic_decouple()) {
38*4882a593Smuzhiyun spin_unlock(&master_lock);
39*4882a593Smuzhiyun goto out;
40*4882a593Smuzhiyun }
41*4882a593Smuzhiyun
42*4882a593Smuzhiyun /* If an error occur, we will have to recouple the gic
43*4882a593Smuzhiyun * manually */
44*4882a593Smuzhiyun recouple = true;
45*4882a593Smuzhiyun
46*4882a593Smuzhiyun /* At this state, as the gic is decoupled, if the other
47*4882a593Smuzhiyun * cpu is in WFI, we have the guarantee it won't be wake
48*4882a593Smuzhiyun * up, so we can safely go to retention */
49*4882a593Smuzhiyun if (!prcmu_is_cpu_in_wfi(this_cpu ? 0 : 1))
50*4882a593Smuzhiyun goto out;
51*4882a593Smuzhiyun
52*4882a593Smuzhiyun /* The prcmu will be in charge of watching the interrupts
53*4882a593Smuzhiyun * and wake up the cpus */
54*4882a593Smuzhiyun if (prcmu_copy_gic_settings())
55*4882a593Smuzhiyun goto out;
56*4882a593Smuzhiyun
57*4882a593Smuzhiyun /* Check in the meantime an interrupt did
58*4882a593Smuzhiyun * not occur on the gic ... */
59*4882a593Smuzhiyun if (prcmu_gic_pending_irq())
60*4882a593Smuzhiyun goto out;
61*4882a593Smuzhiyun
62*4882a593Smuzhiyun /* ... and the prcmu */
63*4882a593Smuzhiyun if (prcmu_pending_irq())
64*4882a593Smuzhiyun goto out;
65*4882a593Smuzhiyun
66*4882a593Smuzhiyun /* Go to the retention state, the prcmu will wait for the
67*4882a593Smuzhiyun * cpu to go WFI and this is what happens after exiting this
68*4882a593Smuzhiyun * 'master' critical section */
69*4882a593Smuzhiyun if (prcmu_set_power_state(PRCMU_AP_IDLE, true, true))
70*4882a593Smuzhiyun goto out;
71*4882a593Smuzhiyun
72*4882a593Smuzhiyun /* When we switch to retention, the prcmu is in charge
73*4882a593Smuzhiyun * of recoupling the gic automatically */
74*4882a593Smuzhiyun recouple = false;
75*4882a593Smuzhiyun
76*4882a593Smuzhiyun spin_unlock(&master_lock);
77*4882a593Smuzhiyun }
78*4882a593Smuzhiyun wfi:
79*4882a593Smuzhiyun cpu_do_idle();
80*4882a593Smuzhiyun out:
81*4882a593Smuzhiyun atomic_dec(&master);
82*4882a593Smuzhiyun
83*4882a593Smuzhiyun if (recouple) {
84*4882a593Smuzhiyun prcmu_gic_recouple();
85*4882a593Smuzhiyun spin_unlock(&master_lock);
86*4882a593Smuzhiyun }
87*4882a593Smuzhiyun
88*4882a593Smuzhiyun return index;
89*4882a593Smuzhiyun }
90*4882a593Smuzhiyun
91*4882a593Smuzhiyun static struct cpuidle_driver ux500_idle_driver = {
92*4882a593Smuzhiyun .name = "ux500_idle",
93*4882a593Smuzhiyun .owner = THIS_MODULE,
94*4882a593Smuzhiyun .states = {
95*4882a593Smuzhiyun ARM_CPUIDLE_WFI_STATE,
96*4882a593Smuzhiyun {
97*4882a593Smuzhiyun .enter = ux500_enter_idle,
98*4882a593Smuzhiyun .exit_latency = 70,
99*4882a593Smuzhiyun .target_residency = 260,
100*4882a593Smuzhiyun .flags = CPUIDLE_FLAG_TIMER_STOP,
101*4882a593Smuzhiyun .name = "ApIdle",
102*4882a593Smuzhiyun .desc = "ARM Retention",
103*4882a593Smuzhiyun },
104*4882a593Smuzhiyun },
105*4882a593Smuzhiyun .safe_state_index = 0,
106*4882a593Smuzhiyun .state_count = 2,
107*4882a593Smuzhiyun };
108*4882a593Smuzhiyun
dbx500_cpuidle_probe(struct platform_device * pdev)109*4882a593Smuzhiyun static int dbx500_cpuidle_probe(struct platform_device *pdev)
110*4882a593Smuzhiyun {
111*4882a593Smuzhiyun /* Configure wake up reasons */
112*4882a593Smuzhiyun prcmu_enable_wakeups(PRCMU_WAKEUP(ARM) | PRCMU_WAKEUP(RTC) |
113*4882a593Smuzhiyun PRCMU_WAKEUP(ABB));
114*4882a593Smuzhiyun
115*4882a593Smuzhiyun return cpuidle_register(&ux500_idle_driver, NULL);
116*4882a593Smuzhiyun }
117*4882a593Smuzhiyun
118*4882a593Smuzhiyun static struct platform_driver dbx500_cpuidle_plat_driver = {
119*4882a593Smuzhiyun .driver = {
120*4882a593Smuzhiyun .name = "cpuidle-dbx500",
121*4882a593Smuzhiyun },
122*4882a593Smuzhiyun .probe = dbx500_cpuidle_probe,
123*4882a593Smuzhiyun };
124*4882a593Smuzhiyun builtin_platform_driver(dbx500_cpuidle_plat_driver);
125