1 // SPDX-License-Identifier: GPL-2.0 or MIT 2 /* Copyright 2019 Collabora ltd. */ 3 4 #include <linux/clk.h> 5 #include <linux/devfreq.h> 6 #include <linux/devfreq_cooling.h> 7 #include <linux/platform_device.h> 8 #include <linux/pm_opp.h> 9 10 #include <drm/drm_managed.h> 11 #include <drm/drm_print.h> 12 13 #include "panthor_devfreq.h" 14 #include "panthor_device.h" 15 16 /** 17 * struct panthor_devfreq - Device frequency management 18 */ 19 struct panthor_devfreq { 20 /** @devfreq: devfreq device. */ 21 struct devfreq *devfreq; 22 23 /** @gov_data: Governor data. */ 24 struct devfreq_simple_ondemand_data gov_data; 25 26 /** @busy_time: Busy time. */ 27 ktime_t busy_time; 28 29 /** @idle_time: Idle time. */ 30 ktime_t idle_time; 31 32 /** @time_last_update: Last update time. */ 33 ktime_t time_last_update; 34 35 /** @last_busy_state: True if the GPU was busy last time we updated the state. */ 36 bool last_busy_state; 37 38 /** 39 * @lock: Lock used to protect busy_time, idle_time, time_last_update and 40 * last_busy_state. 41 * 42 * These fields can be accessed concurrently by panthor_devfreq_get_dev_status() 43 * and panthor_devfreq_record_{busy,idle}(). 44 */ 45 spinlock_t lock; 46 }; 47 48 static void panthor_devfreq_update_utilization(struct panthor_devfreq *pdevfreq) 49 { 50 ktime_t now, last; 51 52 now = ktime_get(); 53 last = pdevfreq->time_last_update; 54 55 if (pdevfreq->last_busy_state) 56 pdevfreq->busy_time += ktime_sub(now, last); 57 else 58 pdevfreq->idle_time += ktime_sub(now, last); 59 60 pdevfreq->time_last_update = now; 61 } 62 63 static int panthor_devfreq_target(struct device *dev, unsigned long *freq, 64 u32 flags) 65 { 66 struct dev_pm_opp *opp; 67 int err; 68 69 opp = devfreq_recommended_opp(dev, freq, flags); 70 if (IS_ERR(opp)) 71 return PTR_ERR(opp); 72 dev_pm_opp_put(opp); 73 74 err = dev_pm_opp_set_rate(dev, *freq); 75 76 return err; 77 } 78 79 static void panthor_devfreq_reset(struct panthor_devfreq *pdevfreq) 80 { 81 pdevfreq->busy_time = 0; 82 pdevfreq->idle_time = 0; 83 pdevfreq->time_last_update = ktime_get(); 84 } 85 86 static int panthor_devfreq_get_dev_status(struct device *dev, 87 struct devfreq_dev_status *status) 88 { 89 struct panthor_device *ptdev = dev_get_drvdata(dev); 90 struct panthor_devfreq *pdevfreq = ptdev->devfreq; 91 unsigned long irqflags; 92 93 status->current_frequency = clk_get_rate(ptdev->clks.core); 94 95 spin_lock_irqsave(&pdevfreq->lock, irqflags); 96 97 panthor_devfreq_update_utilization(pdevfreq); 98 99 status->total_time = ktime_to_ns(ktime_add(pdevfreq->busy_time, 100 pdevfreq->idle_time)); 101 102 status->busy_time = ktime_to_ns(pdevfreq->busy_time); 103 104 panthor_devfreq_reset(pdevfreq); 105 106 spin_unlock_irqrestore(&pdevfreq->lock, irqflags); 107 108 drm_dbg(&ptdev->base, "busy %lu total %lu %lu %% freq %lu MHz\n", 109 status->busy_time, status->total_time, 110 status->busy_time / (status->total_time / 100), 111 status->current_frequency / 1000 / 1000); 112 113 return 0; 114 } 115 116 static int panthor_devfreq_get_cur_freq(struct device *dev, unsigned long *freq) 117 { 118 struct panthor_device *ptdev = dev_get_drvdata(dev); 119 120 *freq = clk_get_rate(ptdev->clks.core); 121 122 return 0; 123 } 124 125 static struct devfreq_dev_profile panthor_devfreq_profile = { 126 .timer = DEVFREQ_TIMER_DELAYED, 127 .polling_ms = 50, /* ~3 frames */ 128 .target = panthor_devfreq_target, 129 .get_dev_status = panthor_devfreq_get_dev_status, 130 .get_cur_freq = panthor_devfreq_get_cur_freq, 131 }; 132 133 int panthor_devfreq_init(struct panthor_device *ptdev) 134 { 135 /* There's actually 2 regulators (mali and sram), but the OPP core only 136 * supports one. 137 * 138 * We assume the sram regulator is coupled with the mali one and let 139 * the coupling logic deal with voltage updates. 140 */ 141 static const char * const reg_names[] = { "mali", NULL }; 142 struct thermal_cooling_device *cooling; 143 struct device *dev = ptdev->base.dev; 144 struct panthor_devfreq *pdevfreq; 145 struct dev_pm_opp *opp; 146 unsigned long cur_freq; 147 unsigned long freq = ULONG_MAX; 148 int ret; 149 150 pdevfreq = drmm_kzalloc(&ptdev->base, sizeof(*ptdev->devfreq), GFP_KERNEL); 151 if (!pdevfreq) 152 return -ENOMEM; 153 154 ptdev->devfreq = pdevfreq; 155 156 ret = devm_pm_opp_set_regulators(dev, reg_names); 157 if (ret && ret != -ENODEV) { 158 if (ret != -EPROBE_DEFER) 159 DRM_DEV_ERROR(dev, "Couldn't set OPP regulators\n"); 160 return ret; 161 } 162 163 ret = devm_pm_opp_of_add_table(dev); 164 if (ret) 165 return ret; 166 167 spin_lock_init(&pdevfreq->lock); 168 169 panthor_devfreq_reset(pdevfreq); 170 171 cur_freq = clk_get_rate(ptdev->clks.core); 172 173 /* Regulator coupling only takes care of synchronizing/balancing voltage 174 * updates, but the coupled regulator needs to be enabled manually. 175 * 176 * We use devm_regulator_get_enable_optional() and keep the sram supply 177 * enabled until the device is removed, just like we do for the mali 178 * supply, which is enabled when dev_pm_opp_set_opp(dev, opp) is called, 179 * and disabled when the opp_table is torn down, using the devm action. 180 * 181 * If we really care about disabling regulators on suspend, we should: 182 * - use devm_regulator_get_optional() here 183 * - call dev_pm_opp_set_opp(dev, NULL) before leaving this function 184 * (this disables the regulator passed to the OPP layer) 185 * - call dev_pm_opp_set_opp(dev, NULL) and 186 * regulator_disable(ptdev->regulators.sram) in 187 * panthor_devfreq_suspend() 188 * - call dev_pm_opp_set_opp(dev, default_opp) and 189 * regulator_enable(ptdev->regulators.sram) in 190 * panthor_devfreq_resume() 191 * 192 * But without knowing if it's beneficial or not (in term of power 193 * consumption), or how much it slows down the suspend/resume steps, 194 * let's just keep regulators enabled for the device lifetime. 195 */ 196 ret = devm_regulator_get_enable_optional(dev, "sram"); 197 if (ret && ret != -ENODEV) { 198 if (ret != -EPROBE_DEFER) 199 DRM_DEV_ERROR(dev, "Couldn't retrieve/enable sram supply\n"); 200 return ret; 201 } 202 203 opp = devfreq_recommended_opp(dev, &cur_freq, 0); 204 if (IS_ERR(opp)) 205 return PTR_ERR(opp); 206 207 panthor_devfreq_profile.initial_freq = cur_freq; 208 209 /* 210 * Set the recommend OPP this will enable and configure the regulator 211 * if any and will avoid a switch off by regulator_late_cleanup() 212 */ 213 ret = dev_pm_opp_set_opp(dev, opp); 214 dev_pm_opp_put(opp); 215 if (ret) { 216 DRM_DEV_ERROR(dev, "Couldn't set recommended OPP\n"); 217 return ret; 218 } 219 220 /* Find the fastest defined rate */ 221 opp = dev_pm_opp_find_freq_floor(dev, &freq); 222 if (IS_ERR(opp)) 223 return PTR_ERR(opp); 224 ptdev->fast_rate = freq; 225 226 dev_pm_opp_put(opp); 227 228 /* 229 * Setup default thresholds for the simple_ondemand governor. 230 * The values are chosen based on experiments. 231 */ 232 pdevfreq->gov_data.upthreshold = 45; 233 pdevfreq->gov_data.downdifferential = 5; 234 235 pdevfreq->devfreq = devm_devfreq_add_device(dev, &panthor_devfreq_profile, 236 DEVFREQ_GOV_SIMPLE_ONDEMAND, 237 &pdevfreq->gov_data); 238 if (IS_ERR(pdevfreq->devfreq)) { 239 DRM_DEV_ERROR(dev, "Couldn't initialize GPU devfreq\n"); 240 ret = PTR_ERR(pdevfreq->devfreq); 241 pdevfreq->devfreq = NULL; 242 return ret; 243 } 244 245 cooling = devfreq_cooling_em_register(pdevfreq->devfreq, NULL); 246 if (IS_ERR(cooling)) 247 DRM_DEV_INFO(dev, "Failed to register cooling device\n"); 248 249 return 0; 250 } 251 252 void panthor_devfreq_resume(struct panthor_device *ptdev) 253 { 254 struct panthor_devfreq *pdevfreq = ptdev->devfreq; 255 256 if (!pdevfreq->devfreq) 257 return; 258 259 panthor_devfreq_reset(pdevfreq); 260 261 drm_WARN_ON(&ptdev->base, devfreq_resume_device(pdevfreq->devfreq)); 262 } 263 264 void panthor_devfreq_suspend(struct panthor_device *ptdev) 265 { 266 struct panthor_devfreq *pdevfreq = ptdev->devfreq; 267 268 if (!pdevfreq->devfreq) 269 return; 270 271 drm_WARN_ON(&ptdev->base, devfreq_suspend_device(pdevfreq->devfreq)); 272 } 273 274 void panthor_devfreq_record_busy(struct panthor_device *ptdev) 275 { 276 struct panthor_devfreq *pdevfreq = ptdev->devfreq; 277 unsigned long irqflags; 278 279 if (!pdevfreq->devfreq) 280 return; 281 282 spin_lock_irqsave(&pdevfreq->lock, irqflags); 283 284 panthor_devfreq_update_utilization(pdevfreq); 285 pdevfreq->last_busy_state = true; 286 287 spin_unlock_irqrestore(&pdevfreq->lock, irqflags); 288 } 289 290 void panthor_devfreq_record_idle(struct panthor_device *ptdev) 291 { 292 struct panthor_devfreq *pdevfreq = ptdev->devfreq; 293 unsigned long irqflags; 294 295 if (!pdevfreq->devfreq) 296 return; 297 298 spin_lock_irqsave(&pdevfreq->lock, irqflags); 299 300 panthor_devfreq_update_utilization(pdevfreq); 301 pdevfreq->last_busy_state = false; 302 303 spin_unlock_irqrestore(&pdevfreq->lock, irqflags); 304 } 305 306 unsigned long panthor_devfreq_get_freq(struct panthor_device *ptdev) 307 { 308 struct panthor_devfreq *pdevfreq = ptdev->devfreq; 309 unsigned long freq = 0; 310 int ret; 311 312 if (!pdevfreq->devfreq) 313 return 0; 314 315 ret = pdevfreq->devfreq->profile->get_cur_freq(ptdev->base.dev, &freq); 316 if (ret) 317 return 0; 318 319 return freq; 320 } 321