summaryrefslogtreecommitdiff
path: root/drivers/gpu/drm/i915/intel_runtime_pm.h
blob: 1e4ddd11c12bb0008bd5c6538a23b3bdd78e4e34 (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
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
/* SPDX-License-Identifier: MIT */
/*
 * Copyright © 2019 Intel Corporation
 */

#ifndef __INTEL_RUNTIME_PM_H__
#define __INTEL_RUNTIME_PM_H__

#include <linux/types.h>

#include "display/intel_display.h"

#include "intel_wakeref.h"

#include "i915_utils.h"

struct device;
struct drm_i915_private;
struct drm_printer;

enum i915_drm_suspend_mode {
	I915_DRM_SUSPEND_IDLE,
	I915_DRM_SUSPEND_MEM,
	I915_DRM_SUSPEND_HIBERNATE,
};

/*
 * This struct helps tracking the state needed for runtime PM, which puts the
 * device in PCI D3 state. Notice that when this happens, nothing on the
 * graphics device works, even register access, so we don't get interrupts nor
 * anything else.
 *
 * Every piece of our code that needs to actually touch the hardware needs to
 * either call intel_runtime_pm_get or call intel_display_power_get with the
 * appropriate power domain.
 *
 * Our driver uses the autosuspend delay feature, which means we'll only really
 * suspend if we stay with zero refcount for a certain amount of time. The
 * default value is currently very conservative (see intel_runtime_pm_enable), but
 * it can be changed with the standard runtime PM files from sysfs.
 *
 * The irqs_disabled variable becomes true exactly after we disable the IRQs and
 * goes back to false exactly before we reenable the IRQs. We use this variable
 * to check if someone is trying to enable/disable IRQs while they're supposed
 * to be disabled. This shouldn't happen and we'll print some error messages in
 * case it happens.
 *
 * For more, read the Documentation/power/runtime_pm.rst.
 */
struct intel_runtime_pm {
	atomic_t wakeref_count;
	struct device *kdev; /* points to i915->drm.pdev->dev */
	bool available;
	bool suspended;
	bool irqs_enabled;

#if IS_ENABLED(CONFIG_DRM_I915_DEBUG_RUNTIME_PM)
	/*
	 * To aide detection of wakeref leaks and general misuse, we
	 * track all wakeref holders. With manual markup (i.e. returning
	 * a cookie to each rpm_get caller which they then supply to their
	 * paired rpm_put) we can remove corresponding pairs of and keep
	 * the array trimmed to active wakerefs.
	 */
	struct intel_runtime_pm_debug {
		spinlock_t lock;

		depot_stack_handle_t last_acquire;
		depot_stack_handle_t last_release;

		depot_stack_handle_t *owners;
		unsigned long count;
	} debug;
#endif
};

#define BITS_PER_WAKEREF	\
	BITS_PER_TYPE(struct_member(struct intel_runtime_pm, wakeref_count))
#define INTEL_RPM_WAKELOCK_SHIFT	(BITS_PER_WAKEREF / 2)
#define INTEL_RPM_WAKELOCK_BIAS		(1 << INTEL_RPM_WAKELOCK_SHIFT)
#define INTEL_RPM_RAW_WAKEREF_MASK	(INTEL_RPM_WAKELOCK_BIAS - 1)

static inline int
intel_rpm_raw_wakeref_count(int wakeref_count)
{
	return wakeref_count & INTEL_RPM_RAW_WAKEREF_MASK;
}

static inline int
intel_rpm_wakelock_count(int wakeref_count)
{
	return wakeref_count >> INTEL_RPM_WAKELOCK_SHIFT;
}

static inline void
assert_rpm_device_not_suspended(struct intel_runtime_pm *rpm)
{
	WARN_ONCE(rpm->suspended,
		  "Device suspended during HW access\n");
}

static inline void
__assert_rpm_raw_wakeref_held(struct intel_runtime_pm *rpm, int wakeref_count)
{
	assert_rpm_device_not_suspended(rpm);
	WARN_ONCE(!intel_rpm_raw_wakeref_count(wakeref_count),
		  "RPM raw-wakeref not held\n");
}

static inline void
__assert_rpm_wakelock_held(struct intel_runtime_pm *rpm, int wakeref_count)
{
	__assert_rpm_raw_wakeref_held(rpm, wakeref_count);
	WARN_ONCE(!intel_rpm_wakelock_count(wakeref_count),
		  "RPM wakelock ref not held during HW access\n");
}

static inline void
assert_rpm_raw_wakeref_held(struct intel_runtime_pm *rpm)
{
	__assert_rpm_raw_wakeref_held(rpm, atomic_read(&rpm->wakeref_count));
}

static inline void
assert_rpm_wakelock_held(struct intel_runtime_pm *rpm)
{
	__assert_rpm_wakelock_held(rpm, atomic_read(&rpm->wakeref_count));
}

/**
 * disable_rpm_wakeref_asserts - disable the RPM assert checks
 * @rpm: the intel_runtime_pm structure
 *
 * This function disable asserts that check if we hold an RPM wakelock
 * reference, while keeping the device-not-suspended checks still enabled.
 * It's meant to be used only in special circumstances where our rule about
 * the wakelock refcount wrt. the device power state doesn't hold. According
 * to this rule at any point where we access the HW or want to keep the HW in
 * an active state we must hold an RPM wakelock reference acquired via one of
 * the intel_runtime_pm_get() helpers. Currently there are a few special spots
 * where this rule doesn't hold: the IRQ and suspend/resume handlers, the
 * forcewake release timer, and the GPU RPS and hangcheck works. All other
 * users should avoid using this function.
 *
 * Any calls to this function must have a symmetric call to
 * enable_rpm_wakeref_asserts().
 */
static inline void
disable_rpm_wakeref_asserts(struct intel_runtime_pm *rpm)
{
	atomic_add(INTEL_RPM_WAKELOCK_BIAS + 1,
		   &rpm->wakeref_count);
}

/**
 * enable_rpm_wakeref_asserts - re-enable the RPM assert checks
 * @rpm: the intel_runtime_pm structure
 *
 * This function re-enables the RPM assert checks after disabling them with
 * disable_rpm_wakeref_asserts. It's meant to be used only in special
 * circumstances otherwise its use should be avoided.
 *
 * Any calls to this function must have a symmetric call to
 * disable_rpm_wakeref_asserts().
 */
static inline void
enable_rpm_wakeref_asserts(struct intel_runtime_pm *rpm)
{
	atomic_sub(INTEL_RPM_WAKELOCK_BIAS + 1,
		   &rpm->wakeref_count);
}

void intel_runtime_pm_init_early(struct intel_runtime_pm *rpm);
void intel_runtime_pm_enable(struct intel_runtime_pm *rpm);
void intel_runtime_pm_disable(struct intel_runtime_pm *rpm);
void intel_runtime_pm_driver_release(struct intel_runtime_pm *rpm);

intel_wakeref_t intel_runtime_pm_get(struct intel_runtime_pm *rpm);
intel_wakeref_t intel_runtime_pm_get_if_in_use(struct intel_runtime_pm *rpm);
intel_wakeref_t intel_runtime_pm_get_if_active(struct intel_runtime_pm *rpm);
intel_wakeref_t intel_runtime_pm_get_noresume(struct intel_runtime_pm *rpm);
intel_wakeref_t intel_runtime_pm_get_raw(struct intel_runtime_pm *rpm);

#define with_intel_runtime_pm(rpm, wf) \
	for ((wf) = intel_runtime_pm_get(rpm); (wf); \
	     intel_runtime_pm_put((rpm), (wf)), (wf) = 0)

#define with_intel_runtime_pm_if_in_use(rpm, wf) \
	for ((wf) = intel_runtime_pm_get_if_in_use(rpm); (wf); \
	     intel_runtime_pm_put((rpm), (wf)), (wf) = 0)

#define with_intel_runtime_pm_if_active(rpm, wf) \
	for ((wf) = intel_runtime_pm_get_if_active(rpm); (wf); \
	     intel_runtime_pm_put((rpm), (wf)), (wf) = 0)

void intel_runtime_pm_put_unchecked(struct intel_runtime_pm *rpm);
#if IS_ENABLED(CONFIG_DRM_I915_DEBUG_RUNTIME_PM)
void intel_runtime_pm_put(struct intel_runtime_pm *rpm, intel_wakeref_t wref);
#else
static inline void
intel_runtime_pm_put(struct intel_runtime_pm *rpm, intel_wakeref_t wref)
{
	intel_runtime_pm_put_unchecked(rpm);
}
#endif
void intel_runtime_pm_put_raw(struct intel_runtime_pm *rpm, intel_wakeref_t wref);

#if IS_ENABLED(CONFIG_DRM_I915_DEBUG_RUNTIME_PM)
void print_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm,
				    struct drm_printer *p);
#else
static inline void print_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm,
						  struct drm_printer *p)
{
}
#endif

#endif /* __INTEL_RUNTIME_PM_H__ */