1 /* $NetBSD: intel_runtime_pm.h,v 1.2 2021/12/18 23:45:29 riastradh Exp $ */
2
3 /* SPDX-License-Identifier: MIT */
4 /*
5 * Copyright © 2019 Intel Corporation
6 */
7
8 #ifndef __INTEL_RUNTIME_PM_H__
9 #define __INTEL_RUNTIME_PM_H__
10
11 #include <linux/types.h>
12
13 #include "display/intel_display.h"
14
15 #include "intel_wakeref.h"
16
17 #include "i915_utils.h"
18
19 struct device;
20 struct drm_i915_private;
21 struct drm_printer;
22
23 enum i915_drm_suspend_mode {
24 I915_DRM_SUSPEND_IDLE,
25 I915_DRM_SUSPEND_MEM,
26 I915_DRM_SUSPEND_HIBERNATE,
27 };
28
29 /*
30 * This struct helps tracking the state needed for runtime PM, which puts the
31 * device in PCI D3 state. Notice that when this happens, nothing on the
32 * graphics device works, even register access, so we don't get interrupts nor
33 * anything else.
34 *
35 * Every piece of our code that needs to actually touch the hardware needs to
36 * either call intel_runtime_pm_get or call intel_display_power_get with the
37 * appropriate power domain.
38 *
39 * Our driver uses the autosuspend delay feature, which means we'll only really
40 * suspend if we stay with zero refcount for a certain amount of time. The
41 * default value is currently very conservative (see intel_runtime_pm_enable), but
42 * it can be changed with the standard runtime PM files from sysfs.
43 *
44 * The irqs_disabled variable becomes true exactly after we disable the IRQs and
45 * goes back to false exactly before we reenable the IRQs. We use this variable
46 * to check if someone is trying to enable/disable IRQs while they're supposed
47 * to be disabled. This shouldn't happen and we'll print some error messages in
48 * case it happens.
49 *
50 * For more, read the Documentation/power/runtime_pm.rst.
51 */
52 struct intel_runtime_pm {
53 atomic_t wakeref_count;
54 struct device *kdev; /* points to i915->drm.pdev->dev */
55 bool available;
56 bool suspended;
57 bool irqs_enabled;
58
59 #if IS_ENABLED(CONFIG_DRM_I915_DEBUG_RUNTIME_PM)
60 /*
61 * To aide detection of wakeref leaks and general misuse, we
62 * track all wakeref holders. With manual markup (i.e. returning
63 * a cookie to each rpm_get caller which they then supply to their
64 * paired rpm_put) we can remove corresponding pairs of and keep
65 * the array trimmed to active wakerefs.
66 */
67 struct intel_runtime_pm_debug {
68 spinlock_t lock;
69
70 depot_stack_handle_t last_acquire;
71 depot_stack_handle_t last_release;
72
73 depot_stack_handle_t *owners;
74 unsigned long count;
75 } debug;
76 #endif
77 };
78
79 #define BITS_PER_WAKEREF \
80 BITS_PER_TYPE(struct_member(struct intel_runtime_pm, wakeref_count))
81 #define INTEL_RPM_WAKELOCK_SHIFT (BITS_PER_WAKEREF / 2)
82 #define INTEL_RPM_WAKELOCK_BIAS (1 << INTEL_RPM_WAKELOCK_SHIFT)
83 #define INTEL_RPM_RAW_WAKEREF_MASK (INTEL_RPM_WAKELOCK_BIAS - 1)
84
85 static inline int
intel_rpm_raw_wakeref_count(int wakeref_count)86 intel_rpm_raw_wakeref_count(int wakeref_count)
87 {
88 return wakeref_count & INTEL_RPM_RAW_WAKEREF_MASK;
89 }
90
91 static inline int
intel_rpm_wakelock_count(int wakeref_count)92 intel_rpm_wakelock_count(int wakeref_count)
93 {
94 return wakeref_count >> INTEL_RPM_WAKELOCK_SHIFT;
95 }
96
97 static inline void
assert_rpm_device_not_suspended(struct intel_runtime_pm * rpm)98 assert_rpm_device_not_suspended(struct intel_runtime_pm *rpm)
99 {
100 WARN_ONCE(rpm->suspended,
101 "Device suspended during HW access\n");
102 }
103
104 static inline void
__assert_rpm_raw_wakeref_held(struct intel_runtime_pm * rpm,int wakeref_count)105 __assert_rpm_raw_wakeref_held(struct intel_runtime_pm *rpm, int wakeref_count)
106 {
107 assert_rpm_device_not_suspended(rpm);
108 WARN_ONCE(!intel_rpm_raw_wakeref_count(wakeref_count),
109 "RPM raw-wakeref not held\n");
110 }
111
112 static inline void
__assert_rpm_wakelock_held(struct intel_runtime_pm * rpm,int wakeref_count)113 __assert_rpm_wakelock_held(struct intel_runtime_pm *rpm, int wakeref_count)
114 {
115 __assert_rpm_raw_wakeref_held(rpm, wakeref_count);
116 WARN_ONCE(!intel_rpm_wakelock_count(wakeref_count),
117 "RPM wakelock ref not held during HW access\n");
118 }
119
120 static inline void
assert_rpm_raw_wakeref_held(struct intel_runtime_pm * rpm)121 assert_rpm_raw_wakeref_held(struct intel_runtime_pm *rpm)
122 {
123 __assert_rpm_raw_wakeref_held(rpm, atomic_read(&rpm->wakeref_count));
124 }
125
126 static inline void
assert_rpm_wakelock_held(struct intel_runtime_pm * rpm)127 assert_rpm_wakelock_held(struct intel_runtime_pm *rpm)
128 {
129 __assert_rpm_wakelock_held(rpm, atomic_read(&rpm->wakeref_count));
130 }
131
132 /**
133 * disable_rpm_wakeref_asserts - disable the RPM assert checks
134 * @rpm: the intel_runtime_pm structure
135 *
136 * This function disable asserts that check if we hold an RPM wakelock
137 * reference, while keeping the device-not-suspended checks still enabled.
138 * It's meant to be used only in special circumstances where our rule about
139 * the wakelock refcount wrt. the device power state doesn't hold. According
140 * to this rule at any point where we access the HW or want to keep the HW in
141 * an active state we must hold an RPM wakelock reference acquired via one of
142 * the intel_runtime_pm_get() helpers. Currently there are a few special spots
143 * where this rule doesn't hold: the IRQ and suspend/resume handlers, the
144 * forcewake release timer, and the GPU RPS and hangcheck works. All other
145 * users should avoid using this function.
146 *
147 * Any calls to this function must have a symmetric call to
148 * enable_rpm_wakeref_asserts().
149 */
150 static inline void
disable_rpm_wakeref_asserts(struct intel_runtime_pm * rpm)151 disable_rpm_wakeref_asserts(struct intel_runtime_pm *rpm)
152 {
153 atomic_add(INTEL_RPM_WAKELOCK_BIAS + 1,
154 &rpm->wakeref_count);
155 }
156
157 /**
158 * enable_rpm_wakeref_asserts - re-enable the RPM assert checks
159 * @rpm: the intel_runtime_pm structure
160 *
161 * This function re-enables the RPM assert checks after disabling them with
162 * disable_rpm_wakeref_asserts. It's meant to be used only in special
163 * circumstances otherwise its use should be avoided.
164 *
165 * Any calls to this function must have a symmetric call to
166 * disable_rpm_wakeref_asserts().
167 */
168 static inline void
enable_rpm_wakeref_asserts(struct intel_runtime_pm * rpm)169 enable_rpm_wakeref_asserts(struct intel_runtime_pm *rpm)
170 {
171 atomic_sub(INTEL_RPM_WAKELOCK_BIAS + 1,
172 &rpm->wakeref_count);
173 }
174
175 void intel_runtime_pm_init_early(struct intel_runtime_pm *rpm);
176 void intel_runtime_pm_enable(struct intel_runtime_pm *rpm);
177 void intel_runtime_pm_disable(struct intel_runtime_pm *rpm);
178 void intel_runtime_pm_driver_release(struct intel_runtime_pm *rpm);
179
180 intel_wakeref_t intel_runtime_pm_get(struct intel_runtime_pm *rpm);
181 intel_wakeref_t intel_runtime_pm_get_if_in_use(struct intel_runtime_pm *rpm);
182 intel_wakeref_t intel_runtime_pm_get_noresume(struct intel_runtime_pm *rpm);
183 intel_wakeref_t intel_runtime_pm_get_raw(struct intel_runtime_pm *rpm);
184
185 #define with_intel_runtime_pm(rpm, wf) \
186 for ((wf) = intel_runtime_pm_get(rpm); (wf); \
187 intel_runtime_pm_put((rpm), (wf)), (wf) = 0)
188
189 #define with_intel_runtime_pm_if_in_use(rpm, wf) \
190 for ((wf) = intel_runtime_pm_get_if_in_use(rpm); (wf); \
191 intel_runtime_pm_put((rpm), (wf)), (wf) = 0)
192
193 void intel_runtime_pm_put_unchecked(struct intel_runtime_pm *rpm);
194 #if IS_ENABLED(CONFIG_DRM_I915_DEBUG_RUNTIME_PM)
195 void intel_runtime_pm_put(struct intel_runtime_pm *rpm, intel_wakeref_t wref);
196 #else
197 static inline void
intel_runtime_pm_put(struct intel_runtime_pm * rpm,intel_wakeref_t wref)198 intel_runtime_pm_put(struct intel_runtime_pm *rpm, intel_wakeref_t wref)
199 {
200 intel_runtime_pm_put_unchecked(rpm);
201 }
202 #endif
203 void intel_runtime_pm_put_raw(struct intel_runtime_pm *rpm, intel_wakeref_t wref);
204
205 #if IS_ENABLED(CONFIG_DRM_I915_DEBUG_RUNTIME_PM)
206 void print_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm,
207 struct drm_printer *p);
208 #else
print_intel_runtime_pm_wakeref(struct intel_runtime_pm * rpm,struct drm_printer * p)209 static inline void print_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm,
210 struct drm_printer *p)
211 {
212 }
213 #endif
214
215 #endif /* __INTEL_RUNTIME_PM_H__ */
216