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       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                 :          0 : intel_rpm_raw_wakeref_count(int wakeref_count)
      85                 :            : {
      86                 :          0 :         return wakeref_count & INTEL_RPM_RAW_WAKEREF_MASK;
      87                 :            : }
      88                 :            : 
      89                 :            : static inline int
      90                 :          0 : intel_rpm_wakelock_count(int wakeref_count)
      91                 :            : {
      92                 :          0 :         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                 :          0 : __assert_rpm_raw_wakeref_held(struct intel_runtime_pm *rpm, int wakeref_count)
     104                 :            : {
     105                 :          0 :         assert_rpm_device_not_suspended(rpm);
     106   [ #  #  #  # ]:          0 :         WARN_ONCE(!intel_rpm_raw_wakeref_count(wakeref_count),
     107                 :            :                   "RPM raw-wakeref not held\n");
     108                 :          0 : }
     109                 :            : 
     110                 :            : static inline void
     111                 :          0 : __assert_rpm_wakelock_held(struct intel_runtime_pm *rpm, int wakeref_count)
     112                 :            : {
     113                 :          0 :         __assert_rpm_raw_wakeref_held(rpm, wakeref_count);
     114   [ #  #  #  # ]:          0 :         WARN_ONCE(!intel_rpm_wakelock_count(wakeref_count),
     115                 :            :                   "RPM wakelock ref not held during HW access\n");
     116                 :          0 : }
     117                 :            : 
     118                 :            : static inline void
     119                 :          0 : assert_rpm_raw_wakeref_held(struct intel_runtime_pm *rpm)
     120                 :            : {
     121                 :          0 :         __assert_rpm_raw_wakeref_held(rpm, atomic_read(&rpm->wakeref_count));
     122                 :          0 : }
     123                 :            : 
     124                 :            : static inline void
     125                 :          0 : assert_rpm_wakelock_held(struct intel_runtime_pm *rpm)
     126                 :            : {
     127                 :          0 :         __assert_rpm_wakelock_held(rpm, atomic_read(&rpm->wakeref_count));
     128                 :          0 : }
     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                 :          0 : disable_rpm_wakeref_asserts(struct intel_runtime_pm *rpm)
     150                 :            : {
     151                 :          0 :         atomic_add(INTEL_RPM_WAKELOCK_BIAS + 1,
     152                 :            :                    &rpm->wakeref_count);
     153                 :          0 : }
     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                 :          0 : enable_rpm_wakeref_asserts(struct intel_runtime_pm *rpm)
     168                 :            : {
     169                 :          0 :         atomic_sub(INTEL_RPM_WAKELOCK_BIAS + 1,
     170                 :            :                    &rpm->wakeref_count);
     171                 :          0 : }
     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                 :          0 : intel_runtime_pm_put(struct intel_runtime_pm *rpm, intel_wakeref_t wref)
     197                 :            : {
     198                 :          0 :         intel_runtime_pm_put_unchecked(rpm);
     199                 :          0 : }
     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__ */