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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.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_if_active(struct intel_runtime_pm *rpm);
181 intel_wakeref_t intel_runtime_pm_get_noresume(struct intel_runtime_pm *rpm);
182 intel_wakeref_t intel_runtime_pm_get_raw(struct intel_runtime_pm *rpm);
183 
184 #define with_intel_runtime_pm(rpm, wf) \
185 	for ((wf) = intel_runtime_pm_get(rpm); (wf); \
186 	     intel_runtime_pm_put((rpm), (wf)), (wf) = 0)
187 
188 #define with_intel_runtime_pm_if_in_use(rpm, wf) \
189 	for ((wf) = intel_runtime_pm_get_if_in_use(rpm); (wf); \
190 	     intel_runtime_pm_put((rpm), (wf)), (wf) = 0)
191 
192 #define with_intel_runtime_pm_if_active(rpm, wf) \
193 	for ((wf) = intel_runtime_pm_get_if_active(rpm); (wf); \
194 	     intel_runtime_pm_put((rpm), (wf)), (wf) = 0)
195 
196 void intel_runtime_pm_put_unchecked(struct intel_runtime_pm *rpm);
197 #if IS_ENABLED(CONFIG_DRM_I915_DEBUG_RUNTIME_PM)
198 void intel_runtime_pm_put(struct intel_runtime_pm *rpm, intel_wakeref_t wref);
199 #else
200 static inline void
intel_runtime_pm_put(struct intel_runtime_pm * rpm,intel_wakeref_t wref)201 intel_runtime_pm_put(struct intel_runtime_pm *rpm, intel_wakeref_t wref)
202 {
203 	intel_runtime_pm_put_unchecked(rpm);
204 }
205 #endif
206 void intel_runtime_pm_put_raw(struct intel_runtime_pm *rpm, intel_wakeref_t wref);
207 
208 #if IS_ENABLED(CONFIG_DRM_I915_DEBUG_RUNTIME_PM)
209 void print_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm,
210 				    struct drm_printer *p);
211 #else
print_intel_runtime_pm_wakeref(struct intel_runtime_pm * rpm,struct drm_printer * p)212 static inline void print_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm,
213 						  struct drm_printer *p)
214 {
215 }
216 #endif
217 
218 #endif /* __INTEL_RUNTIME_PM_H__ */
219