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