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 	bool no_wakeref_tracking;
55 
56 	/*
57 	 *  Protects access to lmem usefault list.
58 	 *  It is required, if we are outside of the runtime suspend path,
59 	 *  access to @lmem_userfault_list requires always first grabbing the
60 	 *  runtime pm, to ensure we can't race against runtime suspend.
61 	 *  Once we have that we also need to grab @lmem_userfault_lock,
62 	 *  at which point we have exclusive access.
63 	 *  The runtime suspend path is special since it doesn't really hold any locks,
64 	 *  but instead has exclusive access by virtue of all other accesses requiring
65 	 *  holding the runtime pm wakeref.
66 	 */
67 	spinlock_t lmem_userfault_lock;
68 
69 	/*
70 	 *  Keep list of userfaulted gem obj, which require to release their
71 	 *  mmap mappings at runtime suspend path.
72 	 */
73 	struct list_head lmem_userfault_list;
74 
75 	/* Manual runtime pm autosuspend delay for user GGTT/lmem mmaps */
76 	struct intel_wakeref_auto userfault_wakeref;
77 
78 #if IS_ENABLED(CONFIG_DRM_I915_DEBUG_RUNTIME_PM)
79 	/*
80 	 * To aide detection of wakeref leaks and general misuse, we
81 	 * track all wakeref holders. With manual markup (i.e. returning
82 	 * a cookie to each rpm_get caller which they then supply to their
83 	 * paired rpm_put) we can remove corresponding pairs of and keep
84 	 * the array trimmed to active wakerefs.
85 	 */
86 	struct intel_runtime_pm_debug {
87 		spinlock_t lock;
88 
89 		depot_stack_handle_t last_acquire;
90 		depot_stack_handle_t last_release;
91 
92 		depot_stack_handle_t *owners;
93 		unsigned long count;
94 	} debug;
95 #endif
96 };
97 
98 #define BITS_PER_WAKEREF	\
99 	BITS_PER_TYPE(struct_member(struct intel_runtime_pm, wakeref_count))
100 #define INTEL_RPM_WAKELOCK_SHIFT	(BITS_PER_WAKEREF / 2)
101 #define INTEL_RPM_WAKELOCK_BIAS		(1 << INTEL_RPM_WAKELOCK_SHIFT)
102 #define INTEL_RPM_RAW_WAKEREF_MASK	(INTEL_RPM_WAKELOCK_BIAS - 1)
103 
104 static inline int
intel_rpm_raw_wakeref_count(int wakeref_count)105 intel_rpm_raw_wakeref_count(int wakeref_count)
106 {
107 	return wakeref_count & INTEL_RPM_RAW_WAKEREF_MASK;
108 }
109 
110 static inline int
intel_rpm_wakelock_count(int wakeref_count)111 intel_rpm_wakelock_count(int wakeref_count)
112 {
113 	return wakeref_count >> INTEL_RPM_WAKELOCK_SHIFT;
114 }
115 
116 static inline void
assert_rpm_device_not_suspended(struct intel_runtime_pm * rpm)117 assert_rpm_device_not_suspended(struct intel_runtime_pm *rpm)
118 {
119 	WARN_ONCE(rpm->suspended,
120 		  "Device suspended during HW access\n");
121 }
122 
123 static inline void
__assert_rpm_raw_wakeref_held(struct intel_runtime_pm * rpm,int wakeref_count)124 __assert_rpm_raw_wakeref_held(struct intel_runtime_pm *rpm, int wakeref_count)
125 {
126 	assert_rpm_device_not_suspended(rpm);
127 	WARN_ONCE(!intel_rpm_raw_wakeref_count(wakeref_count),
128 		  "RPM raw-wakeref not held\n");
129 }
130 
131 static inline void
__assert_rpm_wakelock_held(struct intel_runtime_pm * rpm,int wakeref_count)132 __assert_rpm_wakelock_held(struct intel_runtime_pm *rpm, int wakeref_count)
133 {
134 	__assert_rpm_raw_wakeref_held(rpm, wakeref_count);
135 	WARN_ONCE(!intel_rpm_wakelock_count(wakeref_count),
136 		  "RPM wakelock ref not held during HW access\n");
137 }
138 
139 static inline void
assert_rpm_raw_wakeref_held(struct intel_runtime_pm * rpm)140 assert_rpm_raw_wakeref_held(struct intel_runtime_pm *rpm)
141 {
142 	__assert_rpm_raw_wakeref_held(rpm, atomic_read(&rpm->wakeref_count));
143 }
144 
145 static inline void
assert_rpm_wakelock_held(struct intel_runtime_pm * rpm)146 assert_rpm_wakelock_held(struct intel_runtime_pm *rpm)
147 {
148 	__assert_rpm_wakelock_held(rpm, atomic_read(&rpm->wakeref_count));
149 }
150 
151 /**
152  * disable_rpm_wakeref_asserts - disable the RPM assert checks
153  * @rpm: the intel_runtime_pm structure
154  *
155  * This function disable asserts that check if we hold an RPM wakelock
156  * reference, while keeping the device-not-suspended checks still enabled.
157  * It's meant to be used only in special circumstances where our rule about
158  * the wakelock refcount wrt. the device power state doesn't hold. According
159  * to this rule at any point where we access the HW or want to keep the HW in
160  * an active state we must hold an RPM wakelock reference acquired via one of
161  * the intel_runtime_pm_get() helpers. Currently there are a few special spots
162  * where this rule doesn't hold: the IRQ and suspend/resume handlers, the
163  * forcewake release timer, and the GPU RPS and hangcheck works. All other
164  * users should avoid using this function.
165  *
166  * Any calls to this function must have a symmetric call to
167  * enable_rpm_wakeref_asserts().
168  */
169 static inline void
disable_rpm_wakeref_asserts(struct intel_runtime_pm * rpm)170 disable_rpm_wakeref_asserts(struct intel_runtime_pm *rpm)
171 {
172 	atomic_add(INTEL_RPM_WAKELOCK_BIAS + 1,
173 		   &rpm->wakeref_count);
174 }
175 
176 /**
177  * enable_rpm_wakeref_asserts - re-enable the RPM assert checks
178  * @rpm: the intel_runtime_pm structure
179  *
180  * This function re-enables the RPM assert checks after disabling them with
181  * disable_rpm_wakeref_asserts. It's meant to be used only in special
182  * circumstances otherwise its use should be avoided.
183  *
184  * Any calls to this function must have a symmetric call to
185  * disable_rpm_wakeref_asserts().
186  */
187 static inline void
enable_rpm_wakeref_asserts(struct intel_runtime_pm * rpm)188 enable_rpm_wakeref_asserts(struct intel_runtime_pm *rpm)
189 {
190 	atomic_sub(INTEL_RPM_WAKELOCK_BIAS + 1,
191 		   &rpm->wakeref_count);
192 }
193 
194 void intel_runtime_pm_init_early(struct intel_runtime_pm *rpm);
195 void intel_runtime_pm_enable(struct intel_runtime_pm *rpm);
196 void intel_runtime_pm_disable(struct intel_runtime_pm *rpm);
197 void intel_runtime_pm_driver_release(struct intel_runtime_pm *rpm);
198 
199 intel_wakeref_t intel_runtime_pm_get(struct intel_runtime_pm *rpm);
200 intel_wakeref_t intel_runtime_pm_get_if_in_use(struct intel_runtime_pm *rpm);
201 intel_wakeref_t intel_runtime_pm_get_if_active(struct intel_runtime_pm *rpm);
202 intel_wakeref_t intel_runtime_pm_get_noresume(struct intel_runtime_pm *rpm);
203 intel_wakeref_t intel_runtime_pm_get_raw(struct intel_runtime_pm *rpm);
204 
205 #define with_intel_runtime_pm(rpm, wf) \
206 	for ((wf) = intel_runtime_pm_get(rpm); (wf); \
207 	     intel_runtime_pm_put((rpm), (wf)), (wf) = 0)
208 
209 #define with_intel_runtime_pm_if_in_use(rpm, wf) \
210 	for ((wf) = intel_runtime_pm_get_if_in_use(rpm); (wf); \
211 	     intel_runtime_pm_put((rpm), (wf)), (wf) = 0)
212 
213 #define with_intel_runtime_pm_if_active(rpm, wf) \
214 	for ((wf) = intel_runtime_pm_get_if_active(rpm); (wf); \
215 	     intel_runtime_pm_put((rpm), (wf)), (wf) = 0)
216 
217 void intel_runtime_pm_put_unchecked(struct intel_runtime_pm *rpm);
218 #if IS_ENABLED(CONFIG_DRM_I915_DEBUG_RUNTIME_PM)
219 void intel_runtime_pm_put(struct intel_runtime_pm *rpm, intel_wakeref_t wref);
220 #else
221 static inline void
intel_runtime_pm_put(struct intel_runtime_pm * rpm,intel_wakeref_t wref)222 intel_runtime_pm_put(struct intel_runtime_pm *rpm, intel_wakeref_t wref)
223 {
224 	intel_runtime_pm_put_unchecked(rpm);
225 }
226 #endif
227 void intel_runtime_pm_put_raw(struct intel_runtime_pm *rpm, intel_wakeref_t wref);
228 
229 #if IS_ENABLED(CONFIG_DRM_I915_DEBUG_RUNTIME_PM)
230 void print_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm,
231 				    struct drm_printer *p);
232 #else
print_intel_runtime_pm_wakeref(struct intel_runtime_pm * rpm,struct drm_printer * p)233 static inline void print_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm,
234 						  struct drm_printer *p)
235 {
236 }
237 #endif
238 
239 #endif /* __INTEL_RUNTIME_PM_H__ */
240