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 14 struct device; 15 struct drm_i915_private; 16 struct 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 */ 41 struct intel_runtime_pm { 42 atomic_t wakeref_count; 43 struct device *kdev; /* points to i915->drm.dev */ 44 bool available; 45 bool irqs_enabled; 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 88 static inline int 89 intel_rpm_raw_wakeref_count(int wakeref_count) 90 { 91 return wakeref_count & INTEL_RPM_RAW_WAKEREF_MASK; 92 } 93 94 static inline int 95 intel_rpm_wakelock_count(int wakeref_count) 96 { 97 return wakeref_count >> INTEL_RPM_WAKELOCK_SHIFT; 98 } 99 100 static inline void 101 assert_rpm_device_not_suspended(struct intel_runtime_pm *rpm) 102 { 103 WARN_ONCE(pm_runtime_suspended(rpm->kdev), 104 "Device suspended during HW access\n"); 105 } 106 107 static inline void 108 __assert_rpm_raw_wakeref_held(struct intel_runtime_pm *rpm, int wakeref_count) 109 { 110 assert_rpm_device_not_suspended(rpm); 111 WARN_ONCE(!intel_rpm_raw_wakeref_count(wakeref_count), 112 "RPM raw-wakeref not held\n"); 113 } 114 115 static inline void 116 __assert_rpm_wakelock_held(struct intel_runtime_pm *rpm, int wakeref_count) 117 { 118 __assert_rpm_raw_wakeref_held(rpm, wakeref_count); 119 WARN_ONCE(!intel_rpm_wakelock_count(wakeref_count), 120 "RPM wakelock ref not held during HW access\n"); 121 } 122 123 static inline void 124 assert_rpm_raw_wakeref_held(struct intel_runtime_pm *rpm) 125 { 126 __assert_rpm_raw_wakeref_held(rpm, atomic_read(&rpm->wakeref_count)); 127 } 128 129 static inline void 130 assert_rpm_wakelock_held(struct intel_runtime_pm *rpm) 131 { 132 __assert_rpm_wakelock_held(rpm, atomic_read(&rpm->wakeref_count)); 133 } 134 135 /** 136 * disable_rpm_wakeref_asserts - disable the RPM assert checks 137 * @rpm: the intel_runtime_pm structure 138 * 139 * This function disable asserts that check if we hold an RPM wakelock 140 * reference, while keeping the device-not-suspended checks still enabled. 141 * It's meant to be used only in special circumstances where our rule about 142 * the wakelock refcount wrt. the device power state doesn't hold. According 143 * to this rule at any point where we access the HW or want to keep the HW in 144 * an active state we must hold an RPM wakelock reference acquired via one of 145 * the intel_runtime_pm_get() helpers. Currently there are a few special spots 146 * where this rule doesn't hold: the IRQ and suspend/resume handlers, the 147 * forcewake release timer, and the GPU RPS and hangcheck works. All other 148 * users should avoid using this function. 149 * 150 * Any calls to this function must have a symmetric call to 151 * enable_rpm_wakeref_asserts(). 152 */ 153 static inline void 154 disable_rpm_wakeref_asserts(struct intel_runtime_pm *rpm) 155 { 156 atomic_add(INTEL_RPM_WAKELOCK_BIAS + 1, 157 &rpm->wakeref_count); 158 } 159 160 /** 161 * enable_rpm_wakeref_asserts - re-enable the RPM assert checks 162 * @rpm: the intel_runtime_pm structure 163 * 164 * This function re-enables the RPM assert checks after disabling them with 165 * disable_rpm_wakeref_asserts. It's meant to be used only in special 166 * circumstances otherwise its use should be avoided. 167 * 168 * Any calls to this function must have a symmetric call to 169 * disable_rpm_wakeref_asserts(). 170 */ 171 static inline void 172 enable_rpm_wakeref_asserts(struct intel_runtime_pm *rpm) 173 { 174 atomic_sub(INTEL_RPM_WAKELOCK_BIAS + 1, 175 &rpm->wakeref_count); 176 } 177 178 void intel_runtime_pm_init_early(struct intel_runtime_pm *rpm); 179 void intel_runtime_pm_enable(struct intel_runtime_pm *rpm); 180 void intel_runtime_pm_disable(struct intel_runtime_pm *rpm); 181 void intel_runtime_pm_driver_release(struct intel_runtime_pm *rpm); 182 void intel_runtime_pm_driver_last_release(struct intel_runtime_pm *rpm); 183 184 intel_wakeref_t intel_runtime_pm_get(struct intel_runtime_pm *rpm); 185 intel_wakeref_t intel_runtime_pm_get_if_in_use(struct intel_runtime_pm *rpm); 186 intel_wakeref_t intel_runtime_pm_get_if_active(struct intel_runtime_pm *rpm); 187 intel_wakeref_t intel_runtime_pm_get_noresume(struct intel_runtime_pm *rpm); 188 intel_wakeref_t intel_runtime_pm_get_raw(struct intel_runtime_pm *rpm); 189 190 #define with_intel_runtime_pm(rpm, wf) \ 191 for ((wf) = intel_runtime_pm_get(rpm); (wf); \ 192 intel_runtime_pm_put((rpm), (wf)), (wf) = 0) 193 194 #define with_intel_runtime_pm_if_in_use(rpm, wf) \ 195 for ((wf) = intel_runtime_pm_get_if_in_use(rpm); (wf); \ 196 intel_runtime_pm_put((rpm), (wf)), (wf) = 0) 197 198 #define with_intel_runtime_pm_if_active(rpm, wf) \ 199 for ((wf) = intel_runtime_pm_get_if_active(rpm); (wf); \ 200 intel_runtime_pm_put((rpm), (wf)), (wf) = 0) 201 202 void intel_runtime_pm_put_unchecked(struct intel_runtime_pm *rpm); 203 #if IS_ENABLED(CONFIG_DRM_I915_DEBUG_RUNTIME_PM) 204 void intel_runtime_pm_put(struct intel_runtime_pm *rpm, intel_wakeref_t wref); 205 #else 206 static inline void 207 intel_runtime_pm_put(struct intel_runtime_pm *rpm, intel_wakeref_t wref) 208 { 209 intel_runtime_pm_put_unchecked(rpm); 210 } 211 #endif 212 void intel_runtime_pm_put_raw(struct intel_runtime_pm *rpm, intel_wakeref_t wref); 213 214 #if IS_ENABLED(CONFIG_DRM_I915_DEBUG_RUNTIME_PM) 215 void print_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm, 216 struct drm_printer *p); 217 #else 218 static inline void print_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm, 219 struct drm_printer *p) 220 { 221 } 222 #endif 223 224 #endif /* __INTEL_RUNTIME_PM_H__ */ 225