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
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
|
// SPDX-License-Identifier: GPL-2.0-only
/*
* PSCI CPU idle driver.
*
* Copyright (C) 2019 ARM Ltd.
* Author: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
*/
#define pr_fmt(fmt) "CPUidle PSCI: " fmt
#include <linux/cpuidle.h>
#include <linux/cpumask.h>
#include <linux/cpu_pm.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/psci.h>
#include <linux/slab.h>
#include <asm/cpuidle.h>
#include "dt_idle_states.h"
static DEFINE_PER_CPU_READ_MOSTLY(u32 *, psci_power_state);
static int psci_enter_idle_state(struct cpuidle_device *dev,
struct cpuidle_driver *drv, int idx)
{
u32 *state = __this_cpu_read(psci_power_state);
return CPU_PM_CPU_IDLE_ENTER_PARAM(psci_cpu_suspend_enter,
idx, state[idx]);
}
static struct cpuidle_driver psci_idle_driver __initdata = {
.name = "psci_idle",
.owner = THIS_MODULE,
/*
* PSCI idle states relies on architectural WFI to
* be represented as state index 0.
*/
.states[0] = {
.enter = psci_enter_idle_state,
.exit_latency = 1,
.target_residency = 1,
.power_usage = UINT_MAX,
.name = "WFI",
.desc = "ARM WFI",
}
};
static const struct of_device_id psci_idle_state_match[] __initconst = {
{ .compatible = "arm,idle-state",
.data = psci_enter_idle_state },
{ },
};
static int __init psci_dt_parse_state_node(struct device_node *np, u32 *state)
{
int err = of_property_read_u32(np, "arm,psci-suspend-param", state);
if (err) {
pr_warn("%pOF missing arm,psci-suspend-param property\n", np);
return err;
}
if (!psci_power_state_is_valid(*state)) {
pr_warn("Invalid PSCI power state %#x\n", *state);
return -EINVAL;
}
return 0;
}
static int __init psci_dt_cpu_init_idle(struct device_node *cpu_node, int cpu)
{
int i, ret = 0, count = 0;
u32 *psci_states;
struct device_node *state_node;
/* Count idle states */
while ((state_node = of_parse_phandle(cpu_node, "cpu-idle-states",
count))) {
count++;
of_node_put(state_node);
}
if (!count)
return -ENODEV;
count++; /* Add WFI state too */
psci_states = kcalloc(count, sizeof(*psci_states), GFP_KERNEL);
if (!psci_states)
return -ENOMEM;
for (i = 1; i < count; i++) {
state_node = of_parse_phandle(cpu_node, "cpu-idle-states",
i - 1);
ret = psci_dt_parse_state_node(state_node, &psci_states[i]);
of_node_put(state_node);
if (ret)
goto free_mem;
pr_debug("psci-power-state %#x index %d\n", psci_states[i], i);
}
/* Idle states parsed correctly, initialize per-cpu pointer */
per_cpu(psci_power_state, cpu) = psci_states;
return 0;
free_mem:
kfree(psci_states);
return ret;
}
static __init int psci_cpu_init_idle(unsigned int cpu)
{
struct device_node *cpu_node;
int ret;
/*
* If the PSCI cpu_suspend function hook has not been initialized
* idle states must not be enabled, so bail out
*/
if (!psci_ops.cpu_suspend)
return -EOPNOTSUPP;
cpu_node = of_cpu_device_node_get(cpu);
if (!cpu_node)
return -ENODEV;
ret = psci_dt_cpu_init_idle(cpu_node, cpu);
of_node_put(cpu_node);
return ret;
}
static int __init psci_idle_init_cpu(int cpu)
{
struct cpuidle_driver *drv;
struct device_node *cpu_node;
const char *enable_method;
int ret = 0;
cpu_node = of_cpu_device_node_get(cpu);
if (!cpu_node)
return -ENODEV;
/*
* Check whether the enable-method for the cpu is PSCI, fail
* if it is not.
*/
enable_method = of_get_property(cpu_node, "enable-method", NULL);
if (!enable_method || (strcmp(enable_method, "psci")))
ret = -ENODEV;
of_node_put(cpu_node);
if (ret)
return ret;
drv = kmemdup(&psci_idle_driver, sizeof(*drv), GFP_KERNEL);
if (!drv)
return -ENOMEM;
drv->cpumask = (struct cpumask *)cpumask_of(cpu);
/*
* Initialize idle states data, starting at index 1, since
* by default idle state 0 is the quiescent state reached
* by the cpu by executing the wfi instruction.
*
* If no DT idle states are detected (ret == 0) let the driver
* initialization fail accordingly since there is no reason to
* initialize the idle driver if only wfi is supported, the
* default archictectural back-end already executes wfi
* on idle entry.
*/
ret = dt_init_idle_driver(drv, psci_idle_state_match, 1);
if (ret <= 0) {
ret = ret ? : -ENODEV;
goto out_kfree_drv;
}
/*
* Initialize PSCI idle states.
*/
ret = psci_cpu_init_idle(cpu);
if (ret) {
pr_err("CPU %d failed to PSCI idle\n", cpu);
goto out_kfree_drv;
}
ret = cpuidle_register(drv, NULL);
if (ret)
goto out_kfree_drv;
return 0;
out_kfree_drv:
kfree(drv);
return ret;
}
/*
* psci_idle_init - Initializes PSCI cpuidle driver
*
* Initializes PSCI cpuidle driver for all CPUs, if any CPU fails
* to register cpuidle driver then rollback to cancel all CPUs
* registration.
*/
static int __init psci_idle_init(void)
{
int cpu, ret;
struct cpuidle_driver *drv;
struct cpuidle_device *dev;
for_each_possible_cpu(cpu) {
ret = psci_idle_init_cpu(cpu);
if (ret)
goto out_fail;
}
return 0;
out_fail:
while (--cpu >= 0) {
dev = per_cpu(cpuidle_devices, cpu);
drv = cpuidle_get_cpu_driver(dev);
cpuidle_unregister(drv);
kfree(drv);
}
return ret;
}
device_initcall(psci_idle_init);
|
