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 "intel_wakeref.h"
12
13 #include "i915_utils.h"
14
15 struct device;
16 struct drm_i915_private;
17 struct drm_printer;
18
19 /*
20 * This struct helps tracking the state needed for runtime PM, which puts the
21 * device in PCI D3 state. Notice that when this happens, nothing on the
22 * graphics device works, even register access, so we don't get interrupts nor
23 * anything else.
24 *
25 * Every piece of our code that needs to actually touch the hardware needs to
26 * either call intel_runtime_pm_get or call intel_display_power_get with the
27 * appropriate power domain.
28 *
29 * Our driver uses the autosuspend delay feature, which means we'll only really
30 * suspend if we stay with zero refcount for a certain amount of time. The
31 * default value is currently very conservative (see intel_runtime_pm_enable), but
32 * it can be changed with the standard runtime PM files from sysfs.
33 *
34 * The irqs_disabled variable becomes true exactly after we disable the IRQs and
35 * goes back to false exactly before we reenable the IRQs. We use this variable
36 * to check if someone is trying to enable/disable IRQs while they're supposed
37 * to be disabled. This shouldn't happen and we'll print some error messages in
38 * case it happens.
39 *
40 * For more, read the Documentation/power/runtime_pm.rst.
41 */
42 struct intel_runtime_pm {
43 atomic_t wakeref_count;
44 struct device *kdev; /* points to i915->drm.dev */
45 bool available;
46 bool suspended;
47 bool irqs_enabled;
48 bool no_wakeref_tracking;
49
50 /*
51 * Protects access to lmem usefault list.
52 * It is required, if we are outside of the runtime suspend path,
53 * access to @lmem_userfault_list requires always first grabbing the
54 * runtime pm, to ensure we can't race against runtime suspend.
55 * Once we have that we also need to grab @lmem_userfault_lock,
56 * at which point we have exclusive access.
57 * The runtime suspend path is special since it doesn't really hold any locks,
58 * but instead has exclusive access by virtue of all other accesses requiring
59 * holding the runtime pm wakeref.
60 */
61 spinlock_t lmem_userfault_lock;
62
63 /*
64 * Keep list of userfaulted gem obj, which require to release their
65 * mmap mappings at runtime suspend path.
66 */
67 struct list_head lmem_userfault_list;
68
69 /* Manual runtime pm autosuspend delay for user GGTT/lmem mmaps */
70 struct intel_wakeref_auto userfault_wakeref;
71
72 #if IS_ENABLED(CONFIG_DRM_I915_DEBUG_RUNTIME_PM)
73 /*
74 * To aide detection of wakeref leaks and general misuse, we
75 * track all wakeref holders. With manual markup (i.e. returning
76 * a cookie to each rpm_get caller which they then supply to their
77 * paired rpm_put) we can remove corresponding pairs of and keep
78 * the array trimmed to active wakerefs.
79 */
80 struct intel_runtime_pm_debug {
81 spinlock_t lock;
82
83 depot_stack_handle_t last_acquire;
84 depot_stack_handle_t last_release;
85
86 depot_stack_handle_t *owners;
87 unsigned long count;
88 } debug;
89 #endif
90 };
91
92 #define BITS_PER_WAKEREF \
93 BITS_PER_TYPE(typeof_member(struct intel_runtime_pm, wakeref_count))
94 #define INTEL_RPM_WAKELOCK_SHIFT (BITS_PER_WAKEREF / 2)
95 #define INTEL_RPM_WAKELOCK_BIAS (1 << INTEL_RPM_WAKELOCK_SHIFT)
96 #define INTEL_RPM_RAW_WAKEREF_MASK (INTEL_RPM_WAKELOCK_BIAS - 1)
97
98 static inline int
intel_rpm_raw_wakeref_count(int wakeref_count)99 intel_rpm_raw_wakeref_count(int wakeref_count)
100 {
101 return wakeref_count & INTEL_RPM_RAW_WAKEREF_MASK;
102 }
103
104 static inline int
intel_rpm_wakelock_count(int wakeref_count)105 intel_rpm_wakelock_count(int wakeref_count)
106 {
107 return wakeref_count >> INTEL_RPM_WAKELOCK_SHIFT;
108 }
109
110 static inline void
assert_rpm_device_not_suspended(struct intel_runtime_pm * rpm)111 assert_rpm_device_not_suspended(struct intel_runtime_pm *rpm)
112 {
113 WARN_ONCE(rpm->suspended,
114 "Device suspended during HW access\n");
115 }
116
117 static inline void
__assert_rpm_raw_wakeref_held(struct intel_runtime_pm * rpm,int wakeref_count)118 __assert_rpm_raw_wakeref_held(struct intel_runtime_pm *rpm, int wakeref_count)
119 {
120 assert_rpm_device_not_suspended(rpm);
121 WARN_ONCE(!intel_rpm_raw_wakeref_count(wakeref_count),
122 "RPM raw-wakeref not held\n");
123 }
124
125 static inline void
__assert_rpm_wakelock_held(struct intel_runtime_pm * rpm,int wakeref_count)126 __assert_rpm_wakelock_held(struct intel_runtime_pm *rpm, int wakeref_count)
127 {
128 __assert_rpm_raw_wakeref_held(rpm, wakeref_count);
129 WARN_ONCE(!intel_rpm_wakelock_count(wakeref_count),
130 "RPM wakelock ref not held during HW access\n");
131 }
132
133 static inline void
assert_rpm_raw_wakeref_held(struct intel_runtime_pm * rpm)134 assert_rpm_raw_wakeref_held(struct intel_runtime_pm *rpm)
135 {
136 __assert_rpm_raw_wakeref_held(rpm, atomic_read(&rpm->wakeref_count));
137 }
138
139 static inline void
assert_rpm_wakelock_held(struct intel_runtime_pm * rpm)140 assert_rpm_wakelock_held(struct intel_runtime_pm *rpm)
141 {
142 __assert_rpm_wakelock_held(rpm, atomic_read(&rpm->wakeref_count));
143 }
144
145 /**
146 * disable_rpm_wakeref_asserts - disable the RPM assert checks
147 * @rpm: the intel_runtime_pm structure
148 *
149 * This function disable asserts that check if we hold an RPM wakelock
150 * reference, while keeping the device-not-suspended checks still enabled.
151 * It's meant to be used only in special circumstances where our rule about
152 * the wakelock refcount wrt. the device power state doesn't hold. According
153 * to this rule at any point where we access the HW or want to keep the HW in
154 * an active state we must hold an RPM wakelock reference acquired via one of
155 * the intel_runtime_pm_get() helpers. Currently there are a few special spots
156 * where this rule doesn't hold: the IRQ and suspend/resume handlers, the
157 * forcewake release timer, and the GPU RPS and hangcheck works. All other
158 * users should avoid using this function.
159 *
160 * Any calls to this function must have a symmetric call to
161 * enable_rpm_wakeref_asserts().
162 */
163 static inline void
disable_rpm_wakeref_asserts(struct intel_runtime_pm * rpm)164 disable_rpm_wakeref_asserts(struct intel_runtime_pm *rpm)
165 {
166 atomic_add(INTEL_RPM_WAKELOCK_BIAS + 1,
167 &rpm->wakeref_count);
168 }
169
170 /**
171 * enable_rpm_wakeref_asserts - re-enable the RPM assert checks
172 * @rpm: the intel_runtime_pm structure
173 *
174 * This function re-enables the RPM assert checks after disabling them with
175 * disable_rpm_wakeref_asserts. It's meant to be used only in special
176 * circumstances otherwise its use should be avoided.
177 *
178 * Any calls to this function must have a symmetric call to
179 * disable_rpm_wakeref_asserts().
180 */
181 static inline void
enable_rpm_wakeref_asserts(struct intel_runtime_pm * rpm)182 enable_rpm_wakeref_asserts(struct intel_runtime_pm *rpm)
183 {
184 atomic_sub(INTEL_RPM_WAKELOCK_BIAS + 1,
185 &rpm->wakeref_count);
186 }
187
188 void intel_runtime_pm_init_early(struct intel_runtime_pm *rpm);
189 void intel_runtime_pm_enable(struct intel_runtime_pm *rpm);
190 void intel_runtime_pm_disable(struct intel_runtime_pm *rpm);
191 void intel_runtime_pm_driver_release(struct intel_runtime_pm *rpm);
192
193 intel_wakeref_t intel_runtime_pm_get(struct intel_runtime_pm *rpm);
194 intel_wakeref_t intel_runtime_pm_get_if_in_use(struct intel_runtime_pm *rpm);
195 intel_wakeref_t intel_runtime_pm_get_if_active(struct intel_runtime_pm *rpm);
196 intel_wakeref_t intel_runtime_pm_get_noresume(struct intel_runtime_pm *rpm);
197 intel_wakeref_t intel_runtime_pm_get_raw(struct intel_runtime_pm *rpm);
198
199 #define with_intel_runtime_pm(rpm, wf) \
200 for ((wf) = intel_runtime_pm_get(rpm); (wf); \
201 intel_runtime_pm_put((rpm), (wf)), (wf) = 0)
202
203 #define with_intel_runtime_pm_if_in_use(rpm, wf) \
204 for ((wf) = intel_runtime_pm_get_if_in_use(rpm); (wf); \
205 intel_runtime_pm_put((rpm), (wf)), (wf) = 0)
206
207 #define with_intel_runtime_pm_if_active(rpm, wf) \
208 for ((wf) = intel_runtime_pm_get_if_active(rpm); (wf); \
209 intel_runtime_pm_put((rpm), (wf)), (wf) = 0)
210
211 void intel_runtime_pm_put_unchecked(struct intel_runtime_pm *rpm);
212 #if IS_ENABLED(CONFIG_DRM_I915_DEBUG_RUNTIME_PM)
213 void intel_runtime_pm_put(struct intel_runtime_pm *rpm, intel_wakeref_t wref);
214 #else
215 static inline void
intel_runtime_pm_put(struct intel_runtime_pm * rpm,intel_wakeref_t wref)216 intel_runtime_pm_put(struct intel_runtime_pm *rpm, intel_wakeref_t wref)
217 {
218 intel_runtime_pm_put_unchecked(rpm);
219 }
220 #endif
221 void intel_runtime_pm_put_raw(struct intel_runtime_pm *rpm, intel_wakeref_t wref);
222
223 #if IS_ENABLED(CONFIG_DRM_I915_DEBUG_RUNTIME_PM)
224 void print_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm,
225 struct drm_printer *p);
226 #else
print_intel_runtime_pm_wakeref(struct intel_runtime_pm * rpm,struct drm_printer * p)227 static inline void print_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm,
228 struct drm_printer *p)
229 {
230 }
231 #endif
232
233 #endif /* __INTEL_RUNTIME_PM_H__ */
234