summaryrefslogtreecommitdiffstats
path: root/drivers/cpuidle/cpuidle-calxeda.c
blob: e1aab38c5a8da19b076fcc0586565b20313990d5 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
/*
 * Copyright 2012 Calxeda, Inc.
 *
 * Based on arch/arm/plat-mxc/cpuidle.c:
 * Copyright 2012 Freescale Semiconductor, Inc.
 * Copyright 2012 Linaro Ltd.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <linux/cpuidle.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/of.h>
#include <linux/time.h>
#include <linux/delay.h>
#include <linux/suspend.h>
#include <asm/cpuidle.h>
#include <asm/proc-fns.h>
#include <asm/smp_scu.h>
#include <asm/suspend.h>
#include <asm/cacheflush.h>
#include <asm/cp15.h>

extern void highbank_set_cpu_jump(int cpu, void *jump_addr);
extern void *scu_base_addr;

static struct cpuidle_device __percpu *calxeda_idle_cpuidle_devices;

static inline unsigned int get_auxcr(void)
{
	unsigned int val;
	asm("mrc p15, 0, %0, c1, c0, 1	@ get AUXCR" : "=r" (val) : : "cc");
	return val;
}

static inline void set_auxcr(unsigned int val)
{
	asm volatile("mcr p15, 0, %0, c1, c0, 1	@ set AUXCR"
	  : : "r" (val) : "cc");
	isb();
}

static noinline void calxeda_idle_restore(void)
{
	set_cr(get_cr() | CR_C);
	set_auxcr(get_auxcr() | 0x40);
	scu_power_mode(scu_base_addr, SCU_PM_NORMAL);
}

static int calxeda_idle_finish(unsigned long val)
{
	/* Already flushed cache, but do it again as the outer cache functions
	 * dirty the cache with spinlocks */
	flush_cache_all();

	set_auxcr(get_auxcr() & ~0x40);
	set_cr(get_cr() & ~CR_C);

	scu_power_mode(scu_base_addr, SCU_PM_DORMANT);

	cpu_do_idle();

	/* Restore things if we didn't enter power-gating */
	calxeda_idle_restore();
	return 1;
}

static int calxeda_pwrdown_idle(struct cpuidle_device *dev,
				struct cpuidle_driver *drv,
				int index)
{
	highbank_set_cpu_jump(smp_processor_id(), cpu_resume);
	cpu_suspend(0, calxeda_idle_finish);
	return index;
}

static void calxeda_idle_cpuidle_devices_uninit(void)
{
	int i;
	struct cpuidle_device *dev;

	for_each_possible_cpu(i) {
		dev = per_cpu_ptr(calxeda_idle_cpuidle_devices, i);
		cpuidle_unregister_device(dev);
	}

	free_percpu(calxeda_idle_cpuidle_devices);
}

static struct cpuidle_driver calxeda_idle_driver = {
	.name = "calxeda_idle",
	.en_core_tk_irqen = 1,
	.states = {
		ARM_CPUIDLE_WFI_STATE,
		{
			.name = "PG",
			.desc = "Power Gate",
			.flags = CPUIDLE_FLAG_TIME_VALID,
			.exit_latency = 30,
			.power_usage = 50,
			.target_residency = 200,
			.enter = calxeda_pwrdown_idle,
		},
	},
	.state_count = 2,
};

static int __init calxeda_cpuidle_init(void)
{
	int cpu_id;
	int ret;
	struct cpuidle_device *dev;
	struct cpuidle_driver *drv = &calxeda_idle_driver;

	if (!of_machine_is_compatible("calxeda,highbank"))
		return -ENODEV;

	ret = cpuidle_register_driver(drv);
	if (ret)
		return ret;

	calxeda_idle_cpuidle_devices = alloc_percpu(struct cpuidle_device);
	if (calxeda_idle_cpuidle_devices == NULL) {
		ret = -ENOMEM;
		goto unregister_drv;
	}

	/* initialize state data for each cpuidle_device */
	for_each_possible_cpu(cpu_id) {
		dev = per_cpu_ptr(calxeda_idle_cpuidle_devices, cpu_id);
		dev->cpu = cpu_id;
		dev->state_count = drv->state_count;

		ret = cpuidle_register_device(dev);
		if (ret) {
			pr_err("Failed to register cpu %u, error: %d\n",
			       cpu_id, ret);
			goto uninit;
		}
	}

	return 0;

uninit:
	calxeda_idle_cpuidle_devices_uninit();
unregister_drv:
	cpuidle_unregister_driver(drv);
	return ret;
}
module_init(calxeda_cpuidle_init);