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 enum i915_drm_suspend_mode {
20 	I915_DRM_SUSPEND_IDLE,
21 	I915_DRM_SUSPEND_MEM,
22 	I915_DRM_SUSPEND_HIBERNATE,
23 };
24 
25 /*
26  * This struct helps tracking the state needed for runtime PM, which puts the
27  * device in PCI D3 state. Notice that when this happens, nothing on the
28  * graphics device works, even register access, so we don't get interrupts nor
29  * anything else.
30  *
31  * Every piece of our code that needs to actually touch the hardware needs to
32  * either call intel_runtime_pm_get or call intel_display_power_get with the
33  * appropriate power domain.
34  *
35  * Our driver uses the autosuspend delay feature, which means we'll only really
36  * suspend if we stay with zero refcount for a certain amount of time. The
37  * default value is currently very conservative (see intel_runtime_pm_enable), but
38  * it can be changed with the standard runtime PM files from sysfs.
39  *
40  * The irqs_disabled variable becomes true exactly after we disable the IRQs and
41  * goes back to false exactly before we reenable the IRQs. We use this variable
42  * to check if someone is trying to enable/disable IRQs while they're supposed
43  * to be disabled. This shouldn't happen and we'll print some error messages in
44  * case it happens.
45  *
46  * For more, read the Documentation/power/runtime_pm.rst.
47  */
48 struct intel_runtime_pm {
49 	atomic_t wakeref_count;
50 	struct device *kdev; /* points to i915->drm.dev */
51 	bool available;
52 	bool suspended;
53 	bool irqs_enabled;
54 
55 #if IS_ENABLED(CONFIG_DRM_I915_DEBUG_RUNTIME_PM)
56 	/*
57 	 * To aide detection of wakeref leaks and general misuse, we
58 	 * track all wakeref holders. With manual markup (i.e. returning
59 	 * a cookie to each rpm_get caller which they then supply to their
60 	 * paired rpm_put) we can remove corresponding pairs of and keep
61 	 * the array trimmed to active wakerefs.
62 	 */
63 	struct intel_runtime_pm_debug {
64 		spinlock_t lock;
65 
66 		depot_stack_handle_t last_acquire;
67 		depot_stack_handle_t last_release;
68 
69 		depot_stack_handle_t *owners;
70 		unsigned long count;
71 	} debug;
72 #endif
73 };
74 
75 #define BITS_PER_WAKEREF	\
76 	BITS_PER_TYPE(struct_member(struct intel_runtime_pm, wakeref_count))
77 #define INTEL_RPM_WAKELOCK_SHIFT	(BITS_PER_WAKEREF / 2)
78 #define INTEL_RPM_WAKELOCK_BIAS		(1 << INTEL_RPM_WAKELOCK_SHIFT)
79 #define INTEL_RPM_RAW_WAKEREF_MASK	(INTEL_RPM_WAKELOCK_BIAS - 1)
80 
81 static inline int
intel_rpm_raw_wakeref_count(int wakeref_count)82 intel_rpm_raw_wakeref_count(int wakeref_count)
83 {
84 	return wakeref_count & INTEL_RPM_RAW_WAKEREF_MASK;
85 }
86 
87 static inline int
intel_rpm_wakelock_count(int wakeref_count)88 intel_rpm_wakelock_count(int wakeref_count)
89 {
90 	return wakeref_count >> INTEL_RPM_WAKELOCK_SHIFT;
91 }
92 
93 static inline void
assert_rpm_device_not_suspended(struct intel_runtime_pm * rpm)94 assert_rpm_device_not_suspended(struct intel_runtime_pm *rpm)
95 {
96 	WARN_ONCE(rpm->suspended,
97 		  "Device suspended during HW access\n");
98 }
99 
100 static inline void
__assert_rpm_raw_wakeref_held(struct intel_runtime_pm * rpm,int wakeref_count)101 __assert_rpm_raw_wakeref_held(struct intel_runtime_pm *rpm, int wakeref_count)
102 {
103 	assert_rpm_device_not_suspended(rpm);
104 	WARN_ONCE(!intel_rpm_raw_wakeref_count(wakeref_count),
105 		  "RPM raw-wakeref not held\n");
106 }
107 
108 static inline void
__assert_rpm_wakelock_held(struct intel_runtime_pm * rpm,int wakeref_count)109 __assert_rpm_wakelock_held(struct intel_runtime_pm *rpm, int wakeref_count)
110 {
111 	__assert_rpm_raw_wakeref_held(rpm, wakeref_count);
112 	WARN_ONCE(!intel_rpm_wakelock_count(wakeref_count),
113 		  "RPM wakelock ref not held during HW access\n");
114 }
115 
116 static inline void
assert_rpm_raw_wakeref_held(struct intel_runtime_pm * rpm)117 assert_rpm_raw_wakeref_held(struct intel_runtime_pm *rpm)
118 {
119 	__assert_rpm_raw_wakeref_held(rpm, atomic_read(&rpm->wakeref_count));
120 }
121 
122 static inline void
assert_rpm_wakelock_held(struct intel_runtime_pm * rpm)123 assert_rpm_wakelock_held(struct intel_runtime_pm *rpm)
124 {
125 	__assert_rpm_wakelock_held(rpm, atomic_read(&rpm->wakeref_count));
126 }
127 
128 /**
129  * disable_rpm_wakeref_asserts - disable the RPM assert checks
130  * @rpm: the intel_runtime_pm structure
131  *
132  * This function disable asserts that check if we hold an RPM wakelock
133  * reference, while keeping the device-not-suspended checks still enabled.
134  * It's meant to be used only in special circumstances where our rule about
135  * the wakelock refcount wrt. the device power state doesn't hold. According
136  * to this rule at any point where we access the HW or want to keep the HW in
137  * an active state we must hold an RPM wakelock reference acquired via one of
138  * the intel_runtime_pm_get() helpers. Currently there are a few special spots
139  * where this rule doesn't hold: the IRQ and suspend/resume handlers, the
140  * forcewake release timer, and the GPU RPS and hangcheck works. All other
141  * users should avoid using this function.
142  *
143  * Any calls to this function must have a symmetric call to
144  * enable_rpm_wakeref_asserts().
145  */
146 static inline void
disable_rpm_wakeref_asserts(struct intel_runtime_pm * rpm)147 disable_rpm_wakeref_asserts(struct intel_runtime_pm *rpm)
148 {
149 	atomic_add(INTEL_RPM_WAKELOCK_BIAS + 1,
150 		   &rpm->wakeref_count);
151 }
152 
153 /**
154  * enable_rpm_wakeref_asserts - re-enable the RPM assert checks
155  * @rpm: the intel_runtime_pm structure
156  *
157  * This function re-enables the RPM assert checks after disabling them with
158  * disable_rpm_wakeref_asserts. It's meant to be used only in special
159  * circumstances otherwise its use should be avoided.
160  *
161  * Any calls to this function must have a symmetric call to
162  * disable_rpm_wakeref_asserts().
163  */
164 static inline void
enable_rpm_wakeref_asserts(struct intel_runtime_pm * rpm)165 enable_rpm_wakeref_asserts(struct intel_runtime_pm *rpm)
166 {
167 	atomic_sub(INTEL_RPM_WAKELOCK_BIAS + 1,
168 		   &rpm->wakeref_count);
169 }
170 
171 void intel_runtime_pm_init_early(struct intel_runtime_pm *rpm);
172 void intel_runtime_pm_enable(struct intel_runtime_pm *rpm);
173 void intel_runtime_pm_disable(struct intel_runtime_pm *rpm);
174 void intel_runtime_pm_driver_release(struct intel_runtime_pm *rpm);
175 
176 intel_wakeref_t intel_runtime_pm_get(struct intel_runtime_pm *rpm);
177 intel_wakeref_t intel_runtime_pm_get_if_in_use(struct intel_runtime_pm *rpm);
178 intel_wakeref_t intel_runtime_pm_get_if_active(struct intel_runtime_pm *rpm);
179 intel_wakeref_t intel_runtime_pm_get_noresume(struct intel_runtime_pm *rpm);
180 intel_wakeref_t intel_runtime_pm_get_raw(struct intel_runtime_pm *rpm);
181 
182 #define with_intel_runtime_pm(rpm, wf) \
183 	for ((wf) = intel_runtime_pm_get(rpm); (wf); \
184 	     intel_runtime_pm_put((rpm), (wf)), (wf) = 0)
185 
186 #define with_intel_runtime_pm_if_in_use(rpm, wf) \
187 	for ((wf) = intel_runtime_pm_get_if_in_use(rpm); (wf); \
188 	     intel_runtime_pm_put((rpm), (wf)), (wf) = 0)
189 
190 #define with_intel_runtime_pm_if_active(rpm, wf) \
191 	for ((wf) = intel_runtime_pm_get_if_active(rpm); (wf); \
192 	     intel_runtime_pm_put((rpm), (wf)), (wf) = 0)
193 
194 void intel_runtime_pm_put_unchecked(struct intel_runtime_pm *rpm);
195 #if IS_ENABLED(CONFIG_DRM_I915_DEBUG_RUNTIME_PM)
196 void intel_runtime_pm_put(struct intel_runtime_pm *rpm, intel_wakeref_t wref);
197 #else
198 static inline void
intel_runtime_pm_put(struct intel_runtime_pm * rpm,intel_wakeref_t wref)199 intel_runtime_pm_put(struct intel_runtime_pm *rpm, intel_wakeref_t wref)
200 {
201 	intel_runtime_pm_put_unchecked(rpm);
202 }
203 #endif
204 void intel_runtime_pm_put_raw(struct intel_runtime_pm *rpm, intel_wakeref_t wref);
205 
206 #if IS_ENABLED(CONFIG_DRM_I915_DEBUG_RUNTIME_PM)
207 void print_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm,
208 				    struct drm_printer *p);
209 #else
print_intel_runtime_pm_wakeref(struct intel_runtime_pm * rpm,struct drm_printer * p)210 static inline void print_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm,
211 						  struct drm_printer *p)
212 {
213 }
214 #endif
215 
216 #endif /* __INTEL_RUNTIME_PM_H__ */
217