intel_runtime_pm.h

  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
 14struct device;
 15struct drm_i915_private;
 16struct drm_printer;
 17struct intel_display_rpm_interface;
 18
 19/*
 20 * This struct helps tracking the state needed for runtime PM, which puts the
 21 * device in PCI D3 state. Notice that when this happens, nothing on the
 22 * graphics device works, even register access, so we don't get interrupts nor
 23 * anything else.
 24 *
 25 * Every piece of our code that needs to actually touch the hardware needs to
 26 * either call intel_runtime_pm_get or call intel_display_power_get with the
 27 * appropriate power domain.
 28 *
 29 * Our driver uses the autosuspend delay feature, which means we'll only really
 30 * suspend if we stay with zero refcount for a certain amount of time. The
 31 * default value is currently very conservative (see intel_runtime_pm_enable), but
 32 * it can be changed with the standard runtime PM files from sysfs.
 33 *
 34 * The irqs_disabled variable becomes true exactly after we disable the IRQs and
 35 * goes back to false exactly before we re-enable the IRQs. We use this variable
 36 * to check if someone is trying to enable/disable IRQs while they're supposed
 37 * to be disabled. This shouldn't happen and we'll print some error messages in
 38 * case it happens.
 39 *
 40 * For more, read the Documentation/power/runtime_pm.rst.
 41 */
 42struct intel_runtime_pm {
 43	atomic_t wakeref_count;
 44	struct device *kdev; /* points to i915->drm.dev */
 45	bool available;
 46	bool no_wakeref_tracking;
 47
 48	/*
 49	 *  Protects access to lmem usefault list.
 50	 *  It is required, if we are outside of the runtime suspend path,
 51	 *  access to @lmem_userfault_list requires always first grabbing the
 52	 *  runtime pm, to ensure we can't race against runtime suspend.
 53	 *  Once we have that we also need to grab @lmem_userfault_lock,
 54	 *  at which point we have exclusive access.
 55	 *  The runtime suspend path is special since it doesn't really hold any locks,
 56	 *  but instead has exclusive access by virtue of all other accesses requiring
 57	 *  holding the runtime pm wakeref.
 58	 */
 59	spinlock_t lmem_userfault_lock;
 60
 61	/*
 62	 *  Keep list of userfaulted gem obj, which require to release their
 63	 *  mmap mappings at runtime suspend path.
 64	 */
 65	struct list_head lmem_userfault_list;
 66
 67	/* Manual runtime pm autosuspend delay for user GGTT/lmem mmaps */
 68	struct intel_wakeref_auto userfault_wakeref;
 69
 70#if IS_ENABLED(CONFIG_DRM_I915_DEBUG_RUNTIME_PM)
 71	/*
 72	 * To aide detection of wakeref leaks and general misuse, we
 73	 * track all wakeref holders. With manual markup (i.e. returning
 74	 * a cookie to each rpm_get caller which they then supply to their
 75	 * paired rpm_put) we can remove corresponding pairs of and keep
 76	 * the array trimmed to active wakerefs.
 77	 */
 78	struct ref_tracker_dir debug;
 79#endif
 80};
 81
 82#define BITS_PER_WAKEREF	\
 83	BITS_PER_TYPE(typeof_member(struct intel_runtime_pm, wakeref_count))
 84#define INTEL_RPM_WAKELOCK_SHIFT	(BITS_PER_WAKEREF / 2)
 85#define INTEL_RPM_WAKELOCK_BIAS		(1 << INTEL_RPM_WAKELOCK_SHIFT)
 86#define INTEL_RPM_RAW_WAKEREF_MASK	(INTEL_RPM_WAKELOCK_BIAS - 1)
 87
 88static inline int
 89intel_rpm_raw_wakeref_count(int wakeref_count)
 90{
 91	return wakeref_count & INTEL_RPM_RAW_WAKEREF_MASK;
 92}
 93
 94static inline int
 95intel_rpm_wakelock_count(int wakeref_count)
 96{
 97	return wakeref_count >> INTEL_RPM_WAKELOCK_SHIFT;
 98}
 99
100static inline bool
101intel_runtime_pm_suspended(struct intel_runtime_pm *rpm)
102{
103	return pm_runtime_suspended(rpm->kdev);
104}
105
106static inline void
107assert_rpm_device_not_suspended(struct intel_runtime_pm *rpm)
108{
109	WARN_ONCE(intel_runtime_pm_suspended(rpm),
110		  "Device suspended during HW access\n");
111}
112
113static inline void
114__assert_rpm_raw_wakeref_held(struct intel_runtime_pm *rpm, int wakeref_count)
115{
116	assert_rpm_device_not_suspended(rpm);
117	WARN_ONCE(!intel_rpm_raw_wakeref_count(wakeref_count),
118		  "RPM raw-wakeref not held\n");
119}
120
121static inline void
122__assert_rpm_wakelock_held(struct intel_runtime_pm *rpm, int wakeref_count)
123{
124	__assert_rpm_raw_wakeref_held(rpm, wakeref_count);
125	WARN_ONCE(!intel_rpm_wakelock_count(wakeref_count),
126		  "RPM wakelock ref not held during HW access\n");
127}
128
129static inline void
130assert_rpm_raw_wakeref_held(struct intel_runtime_pm *rpm)
131{
132	__assert_rpm_raw_wakeref_held(rpm, atomic_read(&rpm->wakeref_count));
133}
134
135static inline void
136assert_rpm_wakelock_held(struct intel_runtime_pm *rpm)
137{
138	__assert_rpm_wakelock_held(rpm, atomic_read(&rpm->wakeref_count));
139}
140
141/**
142 * disable_rpm_wakeref_asserts - disable the RPM assert checks
143 * @rpm: the intel_runtime_pm structure
144 *
145 * This function disable asserts that check if we hold an RPM wakelock
146 * reference, while keeping the device-not-suspended checks still enabled.
147 * It's meant to be used only in special circumstances where our rule about
148 * the wakelock refcount wrt. the device power state doesn't hold. According
149 * to this rule at any point where we access the HW or want to keep the HW in
150 * an active state we must hold an RPM wakelock reference acquired via one of
151 * the intel_runtime_pm_get() helpers. Currently there are a few special spots
152 * where this rule doesn't hold: the IRQ and suspend/resume handlers, the
153 * forcewake release timer, and the GPU RPS and hangcheck works. All other
154 * users should avoid using this function.
155 *
156 * Any calls to this function must have a symmetric call to
157 * enable_rpm_wakeref_asserts().
158 */
159static inline void
160disable_rpm_wakeref_asserts(struct intel_runtime_pm *rpm)
161{
162	atomic_add(INTEL_RPM_WAKELOCK_BIAS + 1,
163		   &rpm->wakeref_count);
164}
165
166/**
167 * enable_rpm_wakeref_asserts - re-enable the RPM assert checks
168 * @rpm: the intel_runtime_pm structure
169 *
170 * This function re-enables the RPM assert checks after disabling them with
171 * disable_rpm_wakeref_asserts. It's meant to be used only in special
172 * circumstances otherwise its use should be avoided.
173 *
174 * Any calls to this function must have a symmetric call to
175 * disable_rpm_wakeref_asserts().
176 */
177static inline void
178enable_rpm_wakeref_asserts(struct intel_runtime_pm *rpm)
179{
180	atomic_sub(INTEL_RPM_WAKELOCK_BIAS + 1,
181		   &rpm->wakeref_count);
182}
183
184void intel_runtime_pm_init_early(struct intel_runtime_pm *rpm);
185void intel_runtime_pm_enable(struct intel_runtime_pm *rpm);
186void intel_runtime_pm_disable(struct intel_runtime_pm *rpm);
187void intel_runtime_pm_driver_release(struct intel_runtime_pm *rpm);
188void intel_runtime_pm_driver_last_release(struct intel_runtime_pm *rpm);
189
190intel_wakeref_t intel_runtime_pm_get(struct intel_runtime_pm *rpm);
191intel_wakeref_t intel_runtime_pm_get_if_in_use(struct intel_runtime_pm *rpm);
192intel_wakeref_t intel_runtime_pm_get_if_active(struct intel_runtime_pm *rpm);
193intel_wakeref_t intel_runtime_pm_get_noresume(struct intel_runtime_pm *rpm);
194intel_wakeref_t intel_runtime_pm_get_raw(struct intel_runtime_pm *rpm);
195
196#define with_intel_runtime_pm(rpm, wf) \
197	for ((wf) = intel_runtime_pm_get(rpm); (wf); \
198	     intel_runtime_pm_put((rpm), (wf)), (wf) = NULL)
199
200#define with_intel_runtime_pm_if_in_use(rpm, wf) \
201	for ((wf) = intel_runtime_pm_get_if_in_use(rpm); (wf); \
202	     intel_runtime_pm_put((rpm), (wf)), (wf) = NULL)
203
204#define with_intel_runtime_pm_if_active(rpm, wf) \
205	for ((wf) = intel_runtime_pm_get_if_active(rpm); (wf); \
206	     intel_runtime_pm_put((rpm), (wf)), (wf) = NULL)
207
208void intel_runtime_pm_put_unchecked(struct intel_runtime_pm *rpm);
209#if IS_ENABLED(CONFIG_DRM_I915_DEBUG_RUNTIME_PM)
210void intel_runtime_pm_put(struct intel_runtime_pm *rpm, intel_wakeref_t wref);
211#else
212static inline void
213intel_runtime_pm_put(struct intel_runtime_pm *rpm, intel_wakeref_t wref)
214{
215	intel_runtime_pm_put_unchecked(rpm);
216}
217#endif
218void intel_runtime_pm_put_raw(struct intel_runtime_pm *rpm, intel_wakeref_t wref);
219
220#if IS_ENABLED(CONFIG_DRM_I915_DEBUG_RUNTIME_PM)
221void print_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm,
222				    struct drm_printer *p);
223#else
224static inline void print_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm,
225						  struct drm_printer *p)
226{
227}
228#endif
229
230extern const struct intel_display_rpm_interface i915_display_rpm_interface;
231
232#endif /* __INTEL_RUNTIME_PM_H__ */