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