drivers/gpu/drm/i915/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/types.h>
  10
  11 #include "display/intel_display.h"
  12
  13 #include "intel_wakeref.h"
  14
  15 #include "i915_utils.h"
  16
  17 struct device;
  18 struct drm_i915_private;
  19 struct drm_printer;
  20
  21 enum i915_drm_suspend_mode {
  22         I915_DRM_SUSPEND_IDLE,
  23         I915_DRM_SUSPEND_MEM,
  24         I915_DRM_SUSPEND_HIBERNATE,
  25 };
  26
  27 /*
  28  * This struct helps tracking the state needed for runtime PM, which puts the
  29  * device in PCI D3 state. Notice that when this happens, nothing on the
  30  * graphics device works, even register access, so we don't get interrupts nor
  31  * anything else.
  32  *
  33  * Every piece of our code that needs to actually touch the hardware needs to
  34  * either call intel_runtime_pm_get or call intel_display_power_get with the
  35  * appropriate power domain.
  36  *
  37  * Our driver uses the autosuspend delay feature, which means we'll only really
  38  * suspend if we stay with zero refcount for a certain amount of time. The
  39  * default value is currently very conservative (see intel_runtime_pm_enable), but
  40  * it can be changed with the standard runtime PM files from sysfs.
  41  *
  42  * The irqs_disabled variable becomes true exactly after we disable the IRQs and
  43  * goes back to false exactly before we reenable the IRQs. We use this variable
  44  * to check if someone is trying to enable/disable IRQs while they're supposed
  45  * to be disabled. This shouldn't happen and we'll print some error messages in
  46  * case it happens.
  47  *
  48  * For more, read the Documentation/power/runtime_pm.rst.
  49  */
  50 struct intel_runtime_pm {
  51         atomic_t wakeref_count;
  52         struct device *kdev; /* points to i915->drm.pdev->dev */
  53         bool available;
  54         bool suspended;
  55         bool irqs_enabled;
  56
  57 #if IS_ENABLED(CONFIG_DRM_I915_DEBUG_RUNTIME_PM)
  58         /*
  59          * To aide detection of wakeref leaks and general misuse, we
  60          * track all wakeref holders. With manual markup (i.e. returning
  61          * a cookie to each rpm_get caller which they then supply to their
  62          * paired rpm_put) we can remove corresponding pairs of and keep
  63          * the array trimmed to active wakerefs.
  64          */
  65         struct intel_runtime_pm_debug {
  66                 spinlock_t lock;
  67
  68                 depot_stack_handle_t last_acquire;
  69                 depot_stack_handle_t last_release;
  70
  71                 depot_stack_handle_t *owners;
  72                 unsigned long count;
  73         } debug;
  74 #endif
  75 };
  76
  77 #define BITS_PER_WAKEREF        \
  78         BITS_PER_TYPE(struct_member(struct intel_runtime_pm, wakeref_count))
  79 #define INTEL_RPM_WAKELOCK_SHIFT        (BITS_PER_WAKEREF / 2)
  80 #define INTEL_RPM_WAKELOCK_BIAS         (1 << INTEL_RPM_WAKELOCK_SHIFT)
  81 #define INTEL_RPM_RAW_WAKEREF_MASK      (INTEL_RPM_WAKELOCK_BIAS - 1)
  82
  83 static inline int
  84 intel_rpm_raw_wakeref_count(int wakeref_count)
  85 {
  86         return wakeref_count & INTEL_RPM_RAW_WAKEREF_MASK;
  87 }
  88
  89 static inline int
  90 intel_rpm_wakelock_count(int wakeref_count)
  91 {
  92         return wakeref_count >> INTEL_RPM_WAKELOCK_SHIFT;
  93 }
  94
  95 static inline void
  96 assert_rpm_device_not_suspended(struct intel_runtime_pm *rpm)
  97 {
  98         WARN_ONCE(rpm->suspended,
  99                   "Device suspended during HW access\n");
 100 }
 101
 102 static inline void
 103 __assert_rpm_raw_wakeref_held(struct intel_runtime_pm *rpm, int wakeref_count)
 104 {
 105         assert_rpm_device_not_suspended(rpm);
 106         WARN_ONCE(!intel_rpm_raw_wakeref_count(wakeref_count),
 107                   "RPM raw-wakeref not held\n");
 108 }
 109
 110 static inline void
 111 __assert_rpm_wakelock_held(struct intel_runtime_pm *rpm, int wakeref_count)
 112 {
 113         __assert_rpm_raw_wakeref_held(rpm, wakeref_count);
 114         WARN_ONCE(!intel_rpm_wakelock_count(wakeref_count),
 115                   "RPM wakelock ref not held during HW access\n");
 116 }
 117
 118 static inline void
 119 assert_rpm_raw_wakeref_held(struct intel_runtime_pm *rpm)
 120 {
 121         __assert_rpm_raw_wakeref_held(rpm, atomic_read(&rpm->wakeref_count));
 122 }
 123
 124 static inline void
 125 assert_rpm_wakelock_held(struct intel_runtime_pm *rpm)
 126 {
 127         __assert_rpm_wakelock_held(rpm, atomic_read(&rpm->wakeref_count));
 128 }
 129
 130 /**
 131  * disable_rpm_wakeref_asserts - disable the RPM assert checks
 132  * @rpm: the intel_runtime_pm structure
 133  *
 134  * This function disable asserts that check if we hold an RPM wakelock
 135  * reference, while keeping the device-not-suspended checks still enabled.
 136  * It's meant to be used only in special circumstances where our rule about
 137  * the wakelock refcount wrt. the device power state doesn't hold. According
 138  * to this rule at any point where we access the HW or want to keep the HW in
 139  * an active state we must hold an RPM wakelock reference acquired via one of
 140  * the intel_runtime_pm_get() helpers. Currently there are a few special spots
 141  * where this rule doesn't hold: the IRQ and suspend/resume handlers, the
 142  * forcewake release timer, and the GPU RPS and hangcheck works. All other
 143  * users should avoid using this function.
 144  *
 145  * Any calls to this function must have a symmetric call to
 146  * enable_rpm_wakeref_asserts().
 147  */
 148 static inline void
 149 disable_rpm_wakeref_asserts(struct intel_runtime_pm *rpm)
 150 {
 151         atomic_add(INTEL_RPM_WAKELOCK_BIAS + 1,
 152                    &rpm->wakeref_count);
 153 }
 154
 155 /**
 156  * enable_rpm_wakeref_asserts - re-enable the RPM assert checks
 157  * @rpm: the intel_runtime_pm structure
 158  *
 159  * This function re-enables the RPM assert checks after disabling them with
 160  * disable_rpm_wakeref_asserts. It's meant to be used only in special
 161  * circumstances otherwise its use should be avoided.
 162  *
 163  * Any calls to this function must have a symmetric call to
 164  * disable_rpm_wakeref_asserts().
 165  */
 166 static inline void
 167 enable_rpm_wakeref_asserts(struct intel_runtime_pm *rpm)
 168 {
 169         atomic_sub(INTEL_RPM_WAKELOCK_BIAS + 1,
 170                    &rpm->wakeref_count);
 171 }
 172
 173 void intel_runtime_pm_init_early(struct intel_runtime_pm *rpm);
 174 void intel_runtime_pm_enable(struct intel_runtime_pm *rpm);
 175 void intel_runtime_pm_disable(struct intel_runtime_pm *rpm);
 176 void intel_runtime_pm_driver_release(struct intel_runtime_pm *rpm);
 177
 178 intel_wakeref_t intel_runtime_pm_get(struct intel_runtime_pm *rpm);
 179 intel_wakeref_t intel_runtime_pm_get_if_in_use(struct intel_runtime_pm *rpm);
 180 intel_wakeref_t intel_runtime_pm_get_noresume(struct intel_runtime_pm *rpm);
 181 intel_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 void intel_runtime_pm_put_unchecked(struct intel_runtime_pm *rpm);
 192 #if IS_ENABLED(CONFIG_DRM_I915_DEBUG_RUNTIME_PM)
 193 void intel_runtime_pm_put(struct intel_runtime_pm *rpm, intel_wakeref_t wref);
 194 #else
 195 static inline void
 196 intel_runtime_pm_put(struct intel_runtime_pm *rpm, intel_wakeref_t wref)
 197 {
 198         intel_runtime_pm_put_unchecked(rpm);
 199 }
 200 #endif
 201 void intel_runtime_pm_put_raw(struct intel_runtime_pm *rpm, intel_wakeref_t wref);
 202
 203 #if IS_ENABLED(CONFIG_DRM_I915_DEBUG_RUNTIME_PM)
 204 void print_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm,
 205                                     struct drm_printer *p);
 206 #else
 207 static inline void print_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm,
 208                                                   struct drm_printer *p)
 209 {
 210 }
 211 #endif
 212
 213 #endif /* __INTEL_RUNTIME_PM_H__ */