tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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
15struct device;
16struct drm_i915_private;
17struct drm_printer;
18
19enum 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 */
48struct 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#if IS_ENABLED(CONFIG_DRM_I915_DEBUG_RUNTIME_PM)
57 /*
58 * To aide detection of wakeref leaks and general misuse, we
59 * track all wakeref holders. With manual markup (i.e. returning
60 * a cookie to each rpm_get caller which they then supply to their
61 * paired rpm_put) we can remove corresponding pairs of and keep
62 * the array trimmed to active wakerefs.
63 */
64 struct intel_runtime_pm_debug {
65 spinlock_t lock;
66
67 depot_stack_handle_t last_acquire;
68 depot_stack_handle_t last_release;
69
70 depot_stack_handle_t *owners;
71 unsigned long count;
72 } debug;
73#endif
74};
75
76#define BITS_PER_WAKEREF \
77 BITS_PER_TYPE(struct_member(struct intel_runtime_pm, wakeref_count))
78#define INTEL_RPM_WAKELOCK_SHIFT (BITS_PER_WAKEREF / 2)
79#define INTEL_RPM_WAKELOCK_BIAS (1 << INTEL_RPM_WAKELOCK_SHIFT)
80#define INTEL_RPM_RAW_WAKEREF_MASK (INTEL_RPM_WAKELOCK_BIAS - 1)
81
82static inline int
83intel_rpm_raw_wakeref_count(int wakeref_count)
84{
85 return wakeref_count & INTEL_RPM_RAW_WAKEREF_MASK;
86}
87
88static inline int
89intel_rpm_wakelock_count(int wakeref_count)
90{
91 return wakeref_count >> INTEL_RPM_WAKELOCK_SHIFT;
92}
93
94static inline void
95assert_rpm_device_not_suspended(struct intel_runtime_pm *rpm)
96{
97 WARN_ONCE(rpm->suspended,
98 "Device suspended during HW access\n");
99}
100
101static inline void
102__assert_rpm_raw_wakeref_held(struct intel_runtime_pm *rpm, int wakeref_count)
103{
104 assert_rpm_device_not_suspended(rpm);
105 WARN_ONCE(!intel_rpm_raw_wakeref_count(wakeref_count),
106 "RPM raw-wakeref not held\n");
107}
108
109static inline void
110__assert_rpm_wakelock_held(struct intel_runtime_pm *rpm, int wakeref_count)
111{
112 __assert_rpm_raw_wakeref_held(rpm, wakeref_count);
113 WARN_ONCE(!intel_rpm_wakelock_count(wakeref_count),
114 "RPM wakelock ref not held during HW access\n");
115}
116
117static inline void
118assert_rpm_raw_wakeref_held(struct intel_runtime_pm *rpm)
119{
120 __assert_rpm_raw_wakeref_held(rpm, atomic_read(&rpm->wakeref_count));
121}
122
123static inline void
124assert_rpm_wakelock_held(struct intel_runtime_pm *rpm)
125{
126 __assert_rpm_wakelock_held(rpm, atomic_read(&rpm->wakeref_count));
127}
128
129/**
130 * disable_rpm_wakeref_asserts - disable the RPM assert checks
131 * @rpm: the intel_runtime_pm structure
132 *
133 * This function disable asserts that check if we hold an RPM wakelock
134 * reference, while keeping the device-not-suspended checks still enabled.
135 * It's meant to be used only in special circumstances where our rule about
136 * the wakelock refcount wrt. the device power state doesn't hold. According
137 * to this rule at any point where we access the HW or want to keep the HW in
138 * an active state we must hold an RPM wakelock reference acquired via one of
139 * the intel_runtime_pm_get() helpers. Currently there are a few special spots
140 * where this rule doesn't hold: the IRQ and suspend/resume handlers, the
141 * forcewake release timer, and the GPU RPS and hangcheck works. All other
142 * users should avoid using this function.
143 *
144 * Any calls to this function must have a symmetric call to
145 * enable_rpm_wakeref_asserts().
146 */
147static inline void
148disable_rpm_wakeref_asserts(struct intel_runtime_pm *rpm)
149{
150 atomic_add(INTEL_RPM_WAKELOCK_BIAS + 1,
151 &rpm->wakeref_count);
152}
153
154/**
155 * enable_rpm_wakeref_asserts - re-enable the RPM assert checks
156 * @rpm: the intel_runtime_pm structure
157 *
158 * This function re-enables the RPM assert checks after disabling them with
159 * disable_rpm_wakeref_asserts. It's meant to be used only in special
160 * circumstances otherwise its use should be avoided.
161 *
162 * Any calls to this function must have a symmetric call to
163 * disable_rpm_wakeref_asserts().
164 */
165static inline void
166enable_rpm_wakeref_asserts(struct intel_runtime_pm *rpm)
167{
168 atomic_sub(INTEL_RPM_WAKELOCK_BIAS + 1,
169 &rpm->wakeref_count);
170}
171
172void intel_runtime_pm_init_early(struct intel_runtime_pm *rpm);
173void intel_runtime_pm_enable(struct intel_runtime_pm *rpm);
174void intel_runtime_pm_disable(struct intel_runtime_pm *rpm);
175void intel_runtime_pm_driver_release(struct intel_runtime_pm *rpm);
176
177intel_wakeref_t intel_runtime_pm_get(struct intel_runtime_pm *rpm);
178intel_wakeref_t intel_runtime_pm_get_if_in_use(struct intel_runtime_pm *rpm);
179intel_wakeref_t intel_runtime_pm_get_if_active(struct intel_runtime_pm *rpm);
180intel_wakeref_t intel_runtime_pm_get_noresume(struct intel_runtime_pm *rpm);
181intel_wakeref_t intel_runtime_pm_get_raw(struct intel_runtime_pm *rpm);
182
183#define with_intel_runtime_pm(rpm, wf) \
184 for ((wf) = intel_runtime_pm_get(rpm); (wf); \
185 intel_runtime_pm_put((rpm), (wf)), (wf) = 0)
186
187#define with_intel_runtime_pm_if_in_use(rpm, wf) \
188 for ((wf) = intel_runtime_pm_get_if_in_use(rpm); (wf); \
189 intel_runtime_pm_put((rpm), (wf)), (wf) = 0)
190
191#define with_intel_runtime_pm_if_active(rpm, wf) \
192 for ((wf) = intel_runtime_pm_get_if_active(rpm); (wf); \
193 intel_runtime_pm_put((rpm), (wf)), (wf) = 0)
194
195void intel_runtime_pm_put_unchecked(struct intel_runtime_pm *rpm);
196#if IS_ENABLED(CONFIG_DRM_I915_DEBUG_RUNTIME_PM)
197void intel_runtime_pm_put(struct intel_runtime_pm *rpm, intel_wakeref_t wref);
198#else
199static inline void
200intel_runtime_pm_put(struct intel_runtime_pm *rpm, intel_wakeref_t wref)
201{
202 intel_runtime_pm_put_unchecked(rpm);
203}
204#endif
205void intel_runtime_pm_put_raw(struct intel_runtime_pm *rpm, intel_wakeref_t wref);
206
207#if IS_ENABLED(CONFIG_DRM_I915_DEBUG_RUNTIME_PM)
208void print_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm,
209 struct drm_printer *p);
210#else
211static inline void print_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm,
212 struct drm_printer *p)
213{
214}
215#endif
216
217#endif /* __INTEL_RUNTIME_PM_H__ */