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 #include "i915_utils.h" 15 16 struct device; 17 struct drm_i915_private; 18 struct drm_printer; 19 20 /* 21 * This struct helps tracking the state needed for runtime PM, which puts the 22 * device in PCI D3 state. Notice that when this happens, nothing on the 23 * graphics device works, even register access, so we don't get interrupts nor 24 * anything else. 25 * 26 * Every piece of our code that needs to actually touch the hardware needs to 27 * either call intel_runtime_pm_get or call intel_display_power_get with the 28 * appropriate power domain. 29 * 30 * Our driver uses the autosuspend delay feature, which means we'll only really 31 * suspend if we stay with zero refcount for a certain amount of time. The 32 * default value is currently very conservative (see intel_runtime_pm_enable), but 33 * it can be changed with the standard runtime PM files from sysfs. 34 * 35 * The irqs_disabled variable becomes true exactly after we disable the IRQs and 36 * goes back to false exactly before we reenable the IRQs. We use this variable 37 * to check if someone is trying to enable/disable IRQs while they're supposed 38 * to be disabled. This shouldn't happen and we'll print some error messages in 39 * case it happens. 40 * 41 * For more, read the Documentation/power/runtime_pm.rst. 42 */ 43 struct intel_runtime_pm { 44 atomic_t wakeref_count; 45 struct device *kdev; /* points to i915->drm.dev */ 46 bool available; 47 bool irqs_enabled; 48 bool no_wakeref_tracking; 49 50 /* 51 * Protects access to lmem usefault list. 52 * It is required, if we are outside of the runtime suspend path, 53 * access to @lmem_userfault_list requires always first grabbing the 54 * runtime pm, to ensure we can't race against runtime suspend. 55 * Once we have that we also need to grab @lmem_userfault_lock, 56 * at which point we have exclusive access. 57 * The runtime suspend path is special since it doesn't really hold any locks, 58 * but instead has exclusive access by virtue of all other accesses requiring 59 * holding the runtime pm wakeref. 60 */ 61 spinlock_t lmem_userfault_lock; 62 63 /* 64 * Keep list of userfaulted gem obj, which require to release their 65 * mmap mappings at runtime suspend path. 66 */ 67 struct list_head lmem_userfault_list; 68 69 /* Manual runtime pm autosuspend delay for user GGTT/lmem mmaps */ 70 struct intel_wakeref_auto userfault_wakeref; 71 72 #if IS_ENABLED(CONFIG_DRM_I915_DEBUG_RUNTIME_PM) 73 /* 74 * To aide detection of wakeref leaks and general misuse, we 75 * track all wakeref holders. With manual markup (i.e. returning 76 * a cookie to each rpm_get caller which they then supply to their 77 * paired rpm_put) we can remove corresponding pairs of and keep 78 * the array trimmed to active wakerefs. 79 */ 80 struct intel_runtime_pm_debug { 81 spinlock_t lock; 82 83 depot_stack_handle_t last_acquire; 84 depot_stack_handle_t last_release; 85 86 depot_stack_handle_t *owners; 87 unsigned long count; 88 } debug; 89 #endif 90 }; 91 92 #define BITS_PER_WAKEREF \ 93 BITS_PER_TYPE(typeof_member(struct intel_runtime_pm, wakeref_count)) 94 #define INTEL_RPM_WAKELOCK_SHIFT (BITS_PER_WAKEREF / 2) 95 #define INTEL_RPM_WAKELOCK_BIAS (1 << INTEL_RPM_WAKELOCK_SHIFT) 96 #define INTEL_RPM_RAW_WAKEREF_MASK (INTEL_RPM_WAKELOCK_BIAS - 1) 97 98 static inline int 99 intel_rpm_raw_wakeref_count(int wakeref_count) 100 { 101 return wakeref_count & INTEL_RPM_RAW_WAKEREF_MASK; 102 } 103 104 static inline int 105 intel_rpm_wakelock_count(int wakeref_count) 106 { 107 return wakeref_count >> INTEL_RPM_WAKELOCK_SHIFT; 108 } 109 110 static inline void 111 assert_rpm_device_not_suspended(struct intel_runtime_pm *rpm) 112 { 113 WARN_ONCE(pm_runtime_suspended(rpm->kdev), 114 "Device suspended during HW access\n"); 115 } 116 117 static inline void 118 __assert_rpm_raw_wakeref_held(struct intel_runtime_pm *rpm, int wakeref_count) 119 { 120 assert_rpm_device_not_suspended(rpm); 121 WARN_ONCE(!intel_rpm_raw_wakeref_count(wakeref_count), 122 "RPM raw-wakeref not held\n"); 123 } 124 125 static inline void 126 __assert_rpm_wakelock_held(struct intel_runtime_pm *rpm, int wakeref_count) 127 { 128 __assert_rpm_raw_wakeref_held(rpm, wakeref_count); 129 WARN_ONCE(!intel_rpm_wakelock_count(wakeref_count), 130 "RPM wakelock ref not held during HW access\n"); 131 } 132 133 static inline void 134 assert_rpm_raw_wakeref_held(struct intel_runtime_pm *rpm) 135 { 136 __assert_rpm_raw_wakeref_held(rpm, atomic_read(&rpm->wakeref_count)); 137 } 138 139 static inline void 140 assert_rpm_wakelock_held(struct intel_runtime_pm *rpm) 141 { 142 __assert_rpm_wakelock_held(rpm, atomic_read(&rpm->wakeref_count)); 143 } 144 145 /** 146 * disable_rpm_wakeref_asserts - disable the RPM assert checks 147 * @rpm: the intel_runtime_pm structure 148 * 149 * This function disable asserts that check if we hold an RPM wakelock 150 * reference, while keeping the device-not-suspended checks still enabled. 151 * It's meant to be used only in special circumstances where our rule about 152 * the wakelock refcount wrt. the device power state doesn't hold. According 153 * to this rule at any point where we access the HW or want to keep the HW in 154 * an active state we must hold an RPM wakelock reference acquired via one of 155 * the intel_runtime_pm_get() helpers. Currently there are a few special spots 156 * where this rule doesn't hold: the IRQ and suspend/resume handlers, the 157 * forcewake release timer, and the GPU RPS and hangcheck works. All other 158 * users should avoid using this function. 159 * 160 * Any calls to this function must have a symmetric call to 161 * enable_rpm_wakeref_asserts(). 162 */ 163 static inline void 164 disable_rpm_wakeref_asserts(struct intel_runtime_pm *rpm) 165 { 166 atomic_add(INTEL_RPM_WAKELOCK_BIAS + 1, 167 &rpm->wakeref_count); 168 } 169 170 /** 171 * enable_rpm_wakeref_asserts - re-enable the RPM assert checks 172 * @rpm: the intel_runtime_pm structure 173 * 174 * This function re-enables the RPM assert checks after disabling them with 175 * disable_rpm_wakeref_asserts. It's meant to be used only in special 176 * circumstances otherwise its use should be avoided. 177 * 178 * Any calls to this function must have a symmetric call to 179 * disable_rpm_wakeref_asserts(). 180 */ 181 static inline void 182 enable_rpm_wakeref_asserts(struct intel_runtime_pm *rpm) 183 { 184 atomic_sub(INTEL_RPM_WAKELOCK_BIAS + 1, 185 &rpm->wakeref_count); 186 } 187 188 void intel_runtime_pm_init_early(struct intel_runtime_pm *rpm); 189 void intel_runtime_pm_enable(struct intel_runtime_pm *rpm); 190 void intel_runtime_pm_disable(struct intel_runtime_pm *rpm); 191 void intel_runtime_pm_driver_release(struct intel_runtime_pm *rpm); 192 193 intel_wakeref_t intel_runtime_pm_get(struct intel_runtime_pm *rpm); 194 intel_wakeref_t intel_runtime_pm_get_if_in_use(struct intel_runtime_pm *rpm); 195 intel_wakeref_t intel_runtime_pm_get_if_active(struct intel_runtime_pm *rpm); 196 intel_wakeref_t intel_runtime_pm_get_noresume(struct intel_runtime_pm *rpm); 197 intel_wakeref_t intel_runtime_pm_get_raw(struct intel_runtime_pm *rpm); 198 199 #define with_intel_runtime_pm(rpm, wf) \ 200 for ((wf) = intel_runtime_pm_get(rpm); (wf); \ 201 intel_runtime_pm_put((rpm), (wf)), (wf) = 0) 202 203 #define with_intel_runtime_pm_if_in_use(rpm, wf) \ 204 for ((wf) = intel_runtime_pm_get_if_in_use(rpm); (wf); \ 205 intel_runtime_pm_put((rpm), (wf)), (wf) = 0) 206 207 #define with_intel_runtime_pm_if_active(rpm, wf) \ 208 for ((wf) = intel_runtime_pm_get_if_active(rpm); (wf); \ 209 intel_runtime_pm_put((rpm), (wf)), (wf) = 0) 210 211 void intel_runtime_pm_put_unchecked(struct intel_runtime_pm *rpm); 212 #if IS_ENABLED(CONFIG_DRM_I915_DEBUG_RUNTIME_PM) 213 void intel_runtime_pm_put(struct intel_runtime_pm *rpm, intel_wakeref_t wref); 214 #else 215 static inline void 216 intel_runtime_pm_put(struct intel_runtime_pm *rpm, intel_wakeref_t wref) 217 { 218 intel_runtime_pm_put_unchecked(rpm); 219 } 220 #endif 221 void intel_runtime_pm_put_raw(struct intel_runtime_pm *rpm, intel_wakeref_t wref); 222 223 #if IS_ENABLED(CONFIG_DRM_I915_DEBUG_RUNTIME_PM) 224 void print_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm, 225 struct drm_printer *p); 226 #else 227 static inline void print_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm, 228 struct drm_printer *p) 229 { 230 } 231 #endif 232 233 #endif /* __INTEL_RUNTIME_PM_H__ */ 234