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 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 87 static inline int 88 intel_rpm_raw_wakeref_count(int wakeref_count) 89 { 90 return wakeref_count & INTEL_RPM_RAW_WAKEREF_MASK; 91 } 92 93 static inline int 94 intel_rpm_wakelock_count(int wakeref_count) 95 { 96 return wakeref_count >> INTEL_RPM_WAKELOCK_SHIFT; 97 } 98 99 static inline bool 100 intel_runtime_pm_suspended(struct intel_runtime_pm *rpm) 101 { 102 return pm_runtime_suspended(rpm->kdev); 103 } 104 105 static inline void 106 assert_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 } 111 112 static 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 } 119 120 static 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 } 127 128 static inline void 129 assert_rpm_raw_wakeref_held(struct intel_runtime_pm *rpm) 130 { 131 __assert_rpm_raw_wakeref_held(rpm, atomic_read(&rpm->wakeref_count)); 132 } 133 134 static inline void 135 assert_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 */ 158 static inline void 159 disable_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 */ 176 static inline void 177 enable_rpm_wakeref_asserts(struct intel_runtime_pm *rpm) 178 { 179 atomic_sub(INTEL_RPM_WAKELOCK_BIAS + 1, 180 &rpm->wakeref_count); 181 } 182 183 void intel_runtime_pm_init_early(struct intel_runtime_pm *rpm); 184 void intel_runtime_pm_enable(struct intel_runtime_pm *rpm); 185 void intel_runtime_pm_disable(struct intel_runtime_pm *rpm); 186 void intel_runtime_pm_driver_release(struct intel_runtime_pm *rpm); 187 void intel_runtime_pm_driver_last_release(struct intel_runtime_pm *rpm); 188 189 intel_wakeref_t intel_runtime_pm_get(struct intel_runtime_pm *rpm); 190 intel_wakeref_t intel_runtime_pm_get_if_in_use(struct intel_runtime_pm *rpm); 191 intel_wakeref_t intel_runtime_pm_get_if_active(struct intel_runtime_pm *rpm); 192 intel_wakeref_t intel_runtime_pm_get_noresume(struct intel_runtime_pm *rpm); 193 intel_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) 206 207 void intel_runtime_pm_put_unchecked(struct intel_runtime_pm *rpm); 208 #if IS_ENABLED(CONFIG_DRM_I915_DEBUG_RUNTIME_PM) 209 void intel_runtime_pm_put(struct intel_runtime_pm *rpm, intel_wakeref_t wref); 210 #else 211 static inline void 212 intel_runtime_pm_put(struct intel_runtime_pm *rpm, intel_wakeref_t wref) 213 { 214 intel_runtime_pm_put_unchecked(rpm); 215 } 216 #endif 217 void 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) 220 void print_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm, 221 struct drm_printer *p); 222 #else 223 static 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__ */ 230