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 intel_runtime_pm_debug { 79 spinlock_t lock; 80 81 depot_stack_handle_t last_acquire; 82 depot_stack_handle_t last_release; 83 84 depot_stack_handle_t *owners; 85 unsigned long count; 86 } debug; 87 #endif 88 }; 89 90 #define BITS_PER_WAKEREF \ 91 BITS_PER_TYPE(typeof_member(struct intel_runtime_pm, wakeref_count)) 92 #define INTEL_RPM_WAKELOCK_SHIFT (BITS_PER_WAKEREF / 2) 93 #define INTEL_RPM_WAKELOCK_BIAS (1 << INTEL_RPM_WAKELOCK_SHIFT) 94 #define INTEL_RPM_RAW_WAKEREF_MASK (INTEL_RPM_WAKELOCK_BIAS - 1) 95 96 static inline int 97 intel_rpm_raw_wakeref_count(int wakeref_count) 98 { 99 return wakeref_count & INTEL_RPM_RAW_WAKEREF_MASK; 100 } 101 102 static inline int 103 intel_rpm_wakelock_count(int wakeref_count) 104 { 105 return wakeref_count >> INTEL_RPM_WAKELOCK_SHIFT; 106 } 107 108 static inline void 109 assert_rpm_device_not_suspended(struct intel_runtime_pm *rpm) 110 { 111 WARN_ONCE(pm_runtime_suspended(rpm->kdev), 112 "Device suspended during HW access\n"); 113 } 114 115 static inline void 116 __assert_rpm_raw_wakeref_held(struct intel_runtime_pm *rpm, int wakeref_count) 117 { 118 assert_rpm_device_not_suspended(rpm); 119 WARN_ONCE(!intel_rpm_raw_wakeref_count(wakeref_count), 120 "RPM raw-wakeref not held\n"); 121 } 122 123 static inline void 124 __assert_rpm_wakelock_held(struct intel_runtime_pm *rpm, int wakeref_count) 125 { 126 __assert_rpm_raw_wakeref_held(rpm, wakeref_count); 127 WARN_ONCE(!intel_rpm_wakelock_count(wakeref_count), 128 "RPM wakelock ref not held during HW access\n"); 129 } 130 131 static inline void 132 assert_rpm_raw_wakeref_held(struct intel_runtime_pm *rpm) 133 { 134 __assert_rpm_raw_wakeref_held(rpm, atomic_read(&rpm->wakeref_count)); 135 } 136 137 static inline void 138 assert_rpm_wakelock_held(struct intel_runtime_pm *rpm) 139 { 140 __assert_rpm_wakelock_held(rpm, atomic_read(&rpm->wakeref_count)); 141 } 142 143 /** 144 * disable_rpm_wakeref_asserts - disable the RPM assert checks 145 * @rpm: the intel_runtime_pm structure 146 * 147 * This function disable asserts that check if we hold an RPM wakelock 148 * reference, while keeping the device-not-suspended checks still enabled. 149 * It's meant to be used only in special circumstances where our rule about 150 * the wakelock refcount wrt. the device power state doesn't hold. According 151 * to this rule at any point where we access the HW or want to keep the HW in 152 * an active state we must hold an RPM wakelock reference acquired via one of 153 * the intel_runtime_pm_get() helpers. Currently there are a few special spots 154 * where this rule doesn't hold: the IRQ and suspend/resume handlers, the 155 * forcewake release timer, and the GPU RPS and hangcheck works. All other 156 * users should avoid using this function. 157 * 158 * Any calls to this function must have a symmetric call to 159 * enable_rpm_wakeref_asserts(). 160 */ 161 static inline void 162 disable_rpm_wakeref_asserts(struct intel_runtime_pm *rpm) 163 { 164 atomic_add(INTEL_RPM_WAKELOCK_BIAS + 1, 165 &rpm->wakeref_count); 166 } 167 168 /** 169 * enable_rpm_wakeref_asserts - re-enable the RPM assert checks 170 * @rpm: the intel_runtime_pm structure 171 * 172 * This function re-enables the RPM assert checks after disabling them with 173 * disable_rpm_wakeref_asserts. It's meant to be used only in special 174 * circumstances otherwise its use should be avoided. 175 * 176 * Any calls to this function must have a symmetric call to 177 * disable_rpm_wakeref_asserts(). 178 */ 179 static inline void 180 enable_rpm_wakeref_asserts(struct intel_runtime_pm *rpm) 181 { 182 atomic_sub(INTEL_RPM_WAKELOCK_BIAS + 1, 183 &rpm->wakeref_count); 184 } 185 186 void intel_runtime_pm_init_early(struct intel_runtime_pm *rpm); 187 void intel_runtime_pm_enable(struct intel_runtime_pm *rpm); 188 void intel_runtime_pm_disable(struct intel_runtime_pm *rpm); 189 void intel_runtime_pm_driver_release(struct intel_runtime_pm *rpm); 190 191 intel_wakeref_t intel_runtime_pm_get(struct intel_runtime_pm *rpm); 192 intel_wakeref_t intel_runtime_pm_get_if_in_use(struct intel_runtime_pm *rpm); 193 intel_wakeref_t intel_runtime_pm_get_if_active(struct intel_runtime_pm *rpm); 194 intel_wakeref_t intel_runtime_pm_get_noresume(struct intel_runtime_pm *rpm); 195 intel_wakeref_t intel_runtime_pm_get_raw(struct intel_runtime_pm *rpm); 196 197 #define with_intel_runtime_pm(rpm, wf) \ 198 for ((wf) = intel_runtime_pm_get(rpm); (wf); \ 199 intel_runtime_pm_put((rpm), (wf)), (wf) = 0) 200 201 #define with_intel_runtime_pm_if_in_use(rpm, wf) \ 202 for ((wf) = intel_runtime_pm_get_if_in_use(rpm); (wf); \ 203 intel_runtime_pm_put((rpm), (wf)), (wf) = 0) 204 205 #define with_intel_runtime_pm_if_active(rpm, wf) \ 206 for ((wf) = intel_runtime_pm_get_if_active(rpm); (wf); \ 207 intel_runtime_pm_put((rpm), (wf)), (wf) = 0) 208 209 void intel_runtime_pm_put_unchecked(struct intel_runtime_pm *rpm); 210 #if IS_ENABLED(CONFIG_DRM_I915_DEBUG_RUNTIME_PM) 211 void intel_runtime_pm_put(struct intel_runtime_pm *rpm, intel_wakeref_t wref); 212 #else 213 static inline void 214 intel_runtime_pm_put(struct intel_runtime_pm *rpm, intel_wakeref_t wref) 215 { 216 intel_runtime_pm_put_unchecked(rpm); 217 } 218 #endif 219 void intel_runtime_pm_put_raw(struct intel_runtime_pm *rpm, intel_wakeref_t wref); 220 221 #if IS_ENABLED(CONFIG_DRM_I915_DEBUG_RUNTIME_PM) 222 void print_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm, 223 struct drm_printer *p); 224 #else 225 static inline void print_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm, 226 struct drm_printer *p) 227 { 228 } 229 #endif 230 231 #endif /* __INTEL_RUNTIME_PM_H__ */ 232