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/pm_runtime.h>
10 #include <linux/types.h>
11
12 #include "intel_wakeref.h"
13
14 struct device;
15 struct drm_i915_private;
16 struct drm_printer;
17
18 /*
19 * This struct helps tracking the state needed for runtime PM, which puts the
20 * device in PCI D3 state. Notice that when this happens, nothing on the
21 * graphics device works, even register access, so we don't get interrupts nor
22 * anything else.
23 *
24 * Every piece of our code that needs to actually touch the hardware needs to
25 * either call intel_runtime_pm_get or call intel_display_power_get with the
26 * appropriate power domain.
27 *
28 * Our driver uses the autosuspend delay feature, which means we'll only really
29 * suspend if we stay with zero refcount for a certain amount of time. The
30 * default value is currently very conservative (see intel_runtime_pm_enable), but
31 * it can be changed with the standard runtime PM files from sysfs.
32 *
33 * The irqs_disabled variable becomes true exactly after we disable the IRQs and
34 * goes back to false exactly before we reenable the IRQs. We use this variable
35 * to check if someone is trying to enable/disable IRQs while they're supposed
36 * to be disabled. This shouldn't happen and we'll print some error messages in
37 * case it happens.
38 *
39 * For more, read the Documentation/power/runtime_pm.rst.
40 */
41 struct intel_runtime_pm {
42 atomic_t wakeref_count;
43 struct device *kdev; /* points to i915->drm.dev */
44 bool available;
45 bool irqs_enabled;
46 bool no_wakeref_tracking;
47
48 /*
49 * Protects access to lmem usefault list.
50 * It is required, if we are outside of the runtime suspend path,
51 * access to @lmem_userfault_list requires always first grabbing the
52 * runtime pm, to ensure we can't race against runtime suspend.
53 * Once we have that we also need to grab @lmem_userfault_lock,
54 * at which point we have exclusive access.
55 * The runtime suspend path is special since it doesn't really hold any locks,
56 * but instead has exclusive access by virtue of all other accesses requiring
57 * holding the runtime pm wakeref.
58 */
59 spinlock_t lmem_userfault_lock;
60
61 /*
62 * Keep list of userfaulted gem obj, which require to release their
63 * mmap mappings at runtime suspend path.
64 */
65 struct list_head lmem_userfault_list;
66
67 /* Manual runtime pm autosuspend delay for user GGTT/lmem mmaps */
68 struct intel_wakeref_auto userfault_wakeref;
69
70 #if IS_ENABLED(CONFIG_DRM_I915_DEBUG_RUNTIME_PM)
71 /*
72 * To aide detection of wakeref leaks and general misuse, we
73 * track all wakeref holders. With manual markup (i.e. returning
74 * a cookie to each rpm_get caller which they then supply to their
75 * paired rpm_put) we can remove corresponding pairs of and keep
76 * the array trimmed to active wakerefs.
77 */
78 struct ref_tracker_dir debug;
79 #endif
80 };
81
82 #define BITS_PER_WAKEREF \
83 BITS_PER_TYPE(typeof_member(struct intel_runtime_pm, wakeref_count))
84 #define INTEL_RPM_WAKELOCK_SHIFT (BITS_PER_WAKEREF / 2)
85 #define INTEL_RPM_WAKELOCK_BIAS (1 << INTEL_RPM_WAKELOCK_SHIFT)
86 #define INTEL_RPM_RAW_WAKEREF_MASK (INTEL_RPM_WAKELOCK_BIAS - 1)
87
88 static inline int
intel_rpm_raw_wakeref_count(int wakeref_count)89 intel_rpm_raw_wakeref_count(int wakeref_count)
90 {
91 return wakeref_count & INTEL_RPM_RAW_WAKEREF_MASK;
92 }
93
94 static inline int
intel_rpm_wakelock_count(int wakeref_count)95 intel_rpm_wakelock_count(int wakeref_count)
96 {
97 return wakeref_count >> INTEL_RPM_WAKELOCK_SHIFT;
98 }
99
100 static inline void
assert_rpm_device_not_suspended(struct intel_runtime_pm * rpm)101 assert_rpm_device_not_suspended(struct intel_runtime_pm *rpm)
102 {
103 WARN_ONCE(pm_runtime_suspended(rpm->kdev),
104 "Device suspended during HW access\n");
105 }
106
107 static inline void
__assert_rpm_raw_wakeref_held(struct intel_runtime_pm * rpm,int wakeref_count)108 __assert_rpm_raw_wakeref_held(struct intel_runtime_pm *rpm, int wakeref_count)
109 {
110 assert_rpm_device_not_suspended(rpm);
111 WARN_ONCE(!intel_rpm_raw_wakeref_count(wakeref_count),
112 "RPM raw-wakeref not held\n");
113 }
114
115 static inline void
__assert_rpm_wakelock_held(struct intel_runtime_pm * rpm,int wakeref_count)116 __assert_rpm_wakelock_held(struct intel_runtime_pm *rpm, int wakeref_count)
117 {
118 __assert_rpm_raw_wakeref_held(rpm, wakeref_count);
119 WARN_ONCE(!intel_rpm_wakelock_count(wakeref_count),
120 "RPM wakelock ref not held during HW access\n");
121 }
122
123 static inline void
assert_rpm_raw_wakeref_held(struct intel_runtime_pm * rpm)124 assert_rpm_raw_wakeref_held(struct intel_runtime_pm *rpm)
125 {
126 __assert_rpm_raw_wakeref_held(rpm, atomic_read(&rpm->wakeref_count));
127 }
128
129 static inline void
assert_rpm_wakelock_held(struct intel_runtime_pm * rpm)130 assert_rpm_wakelock_held(struct intel_runtime_pm *rpm)
131 {
132 __assert_rpm_wakelock_held(rpm, atomic_read(&rpm->wakeref_count));
133 }
134
135 /**
136 * disable_rpm_wakeref_asserts - disable the RPM assert checks
137 * @rpm: the intel_runtime_pm structure
138 *
139 * This function disable asserts that check if we hold an RPM wakelock
140 * reference, while keeping the device-not-suspended checks still enabled.
141 * It's meant to be used only in special circumstances where our rule about
142 * the wakelock refcount wrt. the device power state doesn't hold. According
143 * to this rule at any point where we access the HW or want to keep the HW in
144 * an active state we must hold an RPM wakelock reference acquired via one of
145 * the intel_runtime_pm_get() helpers. Currently there are a few special spots
146 * where this rule doesn't hold: the IRQ and suspend/resume handlers, the
147 * forcewake release timer, and the GPU RPS and hangcheck works. All other
148 * users should avoid using this function.
149 *
150 * Any calls to this function must have a symmetric call to
151 * enable_rpm_wakeref_asserts().
152 */
153 static inline void
disable_rpm_wakeref_asserts(struct intel_runtime_pm * rpm)154 disable_rpm_wakeref_asserts(struct intel_runtime_pm *rpm)
155 {
156 atomic_add(INTEL_RPM_WAKELOCK_BIAS + 1,
157 &rpm->wakeref_count);
158 }
159
160 /**
161 * enable_rpm_wakeref_asserts - re-enable the RPM assert checks
162 * @rpm: the intel_runtime_pm structure
163 *
164 * This function re-enables the RPM assert checks after disabling them with
165 * disable_rpm_wakeref_asserts. It's meant to be used only in special
166 * circumstances otherwise its use should be avoided.
167 *
168 * Any calls to this function must have a symmetric call to
169 * disable_rpm_wakeref_asserts().
170 */
171 static inline void
enable_rpm_wakeref_asserts(struct intel_runtime_pm * rpm)172 enable_rpm_wakeref_asserts(struct intel_runtime_pm *rpm)
173 {
174 atomic_sub(INTEL_RPM_WAKELOCK_BIAS + 1,
175 &rpm->wakeref_count);
176 }
177
178 void intel_runtime_pm_init_early(struct intel_runtime_pm *rpm);
179 void intel_runtime_pm_enable(struct intel_runtime_pm *rpm);
180 void intel_runtime_pm_disable(struct intel_runtime_pm *rpm);
181 void intel_runtime_pm_driver_release(struct intel_runtime_pm *rpm);
182 void intel_runtime_pm_driver_last_release(struct intel_runtime_pm *rpm);
183
184 intel_wakeref_t intel_runtime_pm_get(struct intel_runtime_pm *rpm);
185 intel_wakeref_t intel_runtime_pm_get_if_in_use(struct intel_runtime_pm *rpm);
186 intel_wakeref_t intel_runtime_pm_get_if_active(struct intel_runtime_pm *rpm);
187 intel_wakeref_t intel_runtime_pm_get_noresume(struct intel_runtime_pm *rpm);
188 intel_wakeref_t intel_runtime_pm_get_raw(struct intel_runtime_pm *rpm);
189
190 #define with_intel_runtime_pm(rpm, wf) \
191 for ((wf) = intel_runtime_pm_get(rpm); (wf); \
192 intel_runtime_pm_put((rpm), (wf)), (wf) = 0)
193
194 #define with_intel_runtime_pm_if_in_use(rpm, wf) \
195 for ((wf) = intel_runtime_pm_get_if_in_use(rpm); (wf); \
196 intel_runtime_pm_put((rpm), (wf)), (wf) = 0)
197
198 #define with_intel_runtime_pm_if_active(rpm, wf) \
199 for ((wf) = intel_runtime_pm_get_if_active(rpm); (wf); \
200 intel_runtime_pm_put((rpm), (wf)), (wf) = 0)
201
202 void intel_runtime_pm_put_unchecked(struct intel_runtime_pm *rpm);
203 #if IS_ENABLED(CONFIG_DRM_I915_DEBUG_RUNTIME_PM)
204 void intel_runtime_pm_put(struct intel_runtime_pm *rpm, intel_wakeref_t wref);
205 #else
206 static inline void
intel_runtime_pm_put(struct intel_runtime_pm * rpm,intel_wakeref_t wref)207 intel_runtime_pm_put(struct intel_runtime_pm *rpm, intel_wakeref_t wref)
208 {
209 intel_runtime_pm_put_unchecked(rpm);
210 }
211 #endif
212 void intel_runtime_pm_put_raw(struct intel_runtime_pm *rpm, intel_wakeref_t wref);
213
214 #if IS_ENABLED(CONFIG_DRM_I915_DEBUG_RUNTIME_PM)
215 void print_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm,
216 struct drm_printer *p);
217 #else
print_intel_runtime_pm_wakeref(struct intel_runtime_pm * rpm,struct drm_printer * p)218 static inline void print_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm,
219 struct drm_printer *p)
220 {
221 }
222 #endif
223
224 #endif /* __INTEL_RUNTIME_PM_H__ */
225