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#include "i915_utils.h"
15
16struct device;
17struct drm_i915_private;
18struct drm_printer;
19
20/*
21 * This struct helps tracking the state needed for runtime PM, which puts the
22 * device in PCI D3 state. Notice that when this happens, nothing on the
23 * graphics device works, even register access, so we don't get interrupts nor
24 * anything else.
25 *
26 * Every piece of our code that needs to actually touch the hardware needs to
27 * either call intel_runtime_pm_get or call intel_display_power_get with the
28 * appropriate power domain.
29 *
30 * Our driver uses the autosuspend delay feature, which means we'll only really
31 * suspend if we stay with zero refcount for a certain amount of time. The
32 * default value is currently very conservative (see intel_runtime_pm_enable), but
33 * it can be changed with the standard runtime PM files from sysfs.
34 *
35 * The irqs_disabled variable becomes true exactly after we disable the IRQs and
36 * goes back to false exactly before we reenable the IRQs. We use this variable
37 * to check if someone is trying to enable/disable IRQs while they're supposed
38 * to be disabled. This shouldn't happen and we'll print some error messages in
39 * case it happens.
40 *
41 * For more, read the Documentation/power/runtime_pm.rst.
42 */
43struct intel_runtime_pm {
44 atomic_t wakeref_count;
45 struct device *kdev; /* points to i915->drm.dev */
46 bool available;
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
98static inline int
99intel_rpm_raw_wakeref_count(int wakeref_count)
100{
101 return wakeref_count & INTEL_RPM_RAW_WAKEREF_MASK;
102}
103
104static inline int
105intel_rpm_wakelock_count(int wakeref_count)
106{
107 return wakeref_count >> INTEL_RPM_WAKELOCK_SHIFT;
108}
109
110static inline void
111assert_rpm_device_not_suspended(struct intel_runtime_pm *rpm)
112{
113 WARN_ONCE(pm_runtime_suspended(rpm->kdev),
114 "Device suspended during HW access\n");
115}
116
117static inline void
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
125static inline void
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
133static inline void
134assert_rpm_raw_wakeref_held(struct intel_runtime_pm *rpm)
135{
136 __assert_rpm_raw_wakeref_held(rpm, wakeref_count: atomic_read(v: &rpm->wakeref_count));
137}
138
139static inline void
140assert_rpm_wakelock_held(struct intel_runtime_pm *rpm)
141{
142 __assert_rpm_wakelock_held(rpm, wakeref_count: atomic_read(v: &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 */
163static inline void
164disable_rpm_wakeref_asserts(struct intel_runtime_pm *rpm)
165{
166 atomic_add(INTEL_RPM_WAKELOCK_BIAS + 1,
167 v: &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 */
181static inline void
182enable_rpm_wakeref_asserts(struct intel_runtime_pm *rpm)
183{
184 atomic_sub(INTEL_RPM_WAKELOCK_BIAS + 1,
185 v: &rpm->wakeref_count);
186}
187
188void intel_runtime_pm_init_early(struct intel_runtime_pm *rpm);
189void intel_runtime_pm_enable(struct intel_runtime_pm *rpm);
190void intel_runtime_pm_disable(struct intel_runtime_pm *rpm);
191void intel_runtime_pm_driver_release(struct intel_runtime_pm *rpm);
192
193intel_wakeref_t intel_runtime_pm_get(struct intel_runtime_pm *rpm);
194intel_wakeref_t intel_runtime_pm_get_if_in_use(struct intel_runtime_pm *rpm);
195intel_wakeref_t intel_runtime_pm_get_if_active(struct intel_runtime_pm *rpm);
196intel_wakeref_t intel_runtime_pm_get_noresume(struct intel_runtime_pm *rpm);
197intel_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
211void intel_runtime_pm_put_unchecked(struct intel_runtime_pm *rpm);
212#if IS_ENABLED(CONFIG_DRM_I915_DEBUG_RUNTIME_PM)
213void intel_runtime_pm_put(struct intel_runtime_pm *rpm, intel_wakeref_t wref);
214#else
215static inline void
216intel_runtime_pm_put(struct intel_runtime_pm *rpm, intel_wakeref_t wref)
217{
218 intel_runtime_pm_put_unchecked(rpm);
219}
220#endif
221void 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)
224void print_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm,
225 struct drm_printer *p);
226#else
227static 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

source code of linux/drivers/gpu/drm/i915/intel_runtime_pm.h