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	/*
 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
104static inline int
105intel_rpm_raw_wakeref_count(int wakeref_count)
106{
107	return wakeref_count & INTEL_RPM_RAW_WAKEREF_MASK;
108}
109
110static inline int
111intel_rpm_wakelock_count(int wakeref_count)
112{
113	return wakeref_count >> INTEL_RPM_WAKELOCK_SHIFT;
114}
115
116static inline void
117assert_rpm_device_not_suspended(struct intel_runtime_pm *rpm)
118{
119	WARN_ONCE(rpm->suspended,
120		  "Device suspended during HW access\n");
121}
122
123static inline void
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
131static inline void
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
139static inline void
140assert_rpm_raw_wakeref_held(struct intel_runtime_pm *rpm)
141{
142	__assert_rpm_raw_wakeref_held(rpm, atomic_read(&rpm->wakeref_count));
143}
144
145static inline void
146assert_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 */
169static inline void
170disable_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 */
187static inline void
188enable_rpm_wakeref_asserts(struct intel_runtime_pm *rpm)
189{
190	atomic_sub(INTEL_RPM_WAKELOCK_BIAS + 1,
191		   &rpm->wakeref_count);
192}
193
194void intel_runtime_pm_init_early(struct intel_runtime_pm *rpm);
195void intel_runtime_pm_enable(struct intel_runtime_pm *rpm);
196void intel_runtime_pm_disable(struct intel_runtime_pm *rpm);
197void intel_runtime_pm_driver_release(struct intel_runtime_pm *rpm);
198
199intel_wakeref_t intel_runtime_pm_get(struct intel_runtime_pm *rpm);
200intel_wakeref_t intel_runtime_pm_get_if_in_use(struct intel_runtime_pm *rpm);
201intel_wakeref_t intel_runtime_pm_get_if_active(struct intel_runtime_pm *rpm);
202intel_wakeref_t intel_runtime_pm_get_noresume(struct intel_runtime_pm *rpm);
203intel_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
217void intel_runtime_pm_put_unchecked(struct intel_runtime_pm *rpm);
218#if IS_ENABLED(CONFIG_DRM_I915_DEBUG_RUNTIME_PM)
219void intel_runtime_pm_put(struct intel_runtime_pm *rpm, intel_wakeref_t wref);
220#else
221static inline void
222intel_runtime_pm_put(struct intel_runtime_pm *rpm, intel_wakeref_t wref)
223{
224	intel_runtime_pm_put_unchecked(rpm);
225}
226#endif
227void 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)
230void print_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm,
231				    struct drm_printer *p);
232#else
233static 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__ */