1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Intel Quadrature Encoder Peripheral driver 4 * 5 * Copyright (C) 2019-2021 Intel Corporation 6 * 7 * Author: Felipe Balbi (Intel) 8 * Author: Jarkko Nikula <jarkko.nikula@linux.intel.com> 9 * Author: Raymond Tan <raymond.tan@intel.com> 10 */ 11 #include <linux/counter.h> 12 #include <linux/kernel.h> 13 #include <linux/module.h> 14 #include <linux/mutex.h> 15 #include <linux/pci.h> 16 #include <linux/pm_runtime.h> 17 18 #define INTEL_QEPCON 0x00 19 #define INTEL_QEPFLT 0x04 20 #define INTEL_QEPCOUNT 0x08 21 #define INTEL_QEPMAX 0x0c 22 #define INTEL_QEPWDT 0x10 23 #define INTEL_QEPCAPDIV 0x14 24 #define INTEL_QEPCNTR 0x18 25 #define INTEL_QEPCAPBUF 0x1c 26 #define INTEL_QEPINT_STAT 0x20 27 #define INTEL_QEPINT_MASK 0x24 28 29 /* QEPCON */ 30 #define INTEL_QEPCON_EN BIT(0) 31 #define INTEL_QEPCON_FLT_EN BIT(1) 32 #define INTEL_QEPCON_EDGE_A BIT(2) 33 #define INTEL_QEPCON_EDGE_B BIT(3) 34 #define INTEL_QEPCON_EDGE_INDX BIT(4) 35 #define INTEL_QEPCON_SWPAB BIT(5) 36 #define INTEL_QEPCON_OP_MODE BIT(6) 37 #define INTEL_QEPCON_PH_ERR BIT(7) 38 #define INTEL_QEPCON_COUNT_RST_MODE BIT(8) 39 #define INTEL_QEPCON_INDX_GATING_MASK GENMASK(10, 9) 40 #define INTEL_QEPCON_INDX_GATING(n) (((n) & 3) << 9) 41 #define INTEL_QEPCON_INDX_PAL_PBL INTEL_QEPCON_INDX_GATING(0) 42 #define INTEL_QEPCON_INDX_PAL_PBH INTEL_QEPCON_INDX_GATING(1) 43 #define INTEL_QEPCON_INDX_PAH_PBL INTEL_QEPCON_INDX_GATING(2) 44 #define INTEL_QEPCON_INDX_PAH_PBH INTEL_QEPCON_INDX_GATING(3) 45 #define INTEL_QEPCON_CAP_MODE BIT(11) 46 #define INTEL_QEPCON_FIFO_THRE_MASK GENMASK(14, 12) 47 #define INTEL_QEPCON_FIFO_THRE(n) ((((n) - 1) & 7) << 12) 48 #define INTEL_QEPCON_FIFO_EMPTY BIT(15) 49 50 /* QEPFLT */ 51 #define INTEL_QEPFLT_MAX_COUNT(n) ((n) & 0x1fffff) 52 53 /* QEPINT */ 54 #define INTEL_QEPINT_FIFOCRIT BIT(5) 55 #define INTEL_QEPINT_FIFOENTRY BIT(4) 56 #define INTEL_QEPINT_QEPDIR BIT(3) 57 #define INTEL_QEPINT_QEPRST_UP BIT(2) 58 #define INTEL_QEPINT_QEPRST_DOWN BIT(1) 59 #define INTEL_QEPINT_WDT BIT(0) 60 61 #define INTEL_QEPINT_MASK_ALL GENMASK(5, 0) 62 63 #define INTEL_QEP_CLK_PERIOD_NS 10 64 65 struct intel_qep { 66 struct mutex lock; 67 struct device *dev; 68 void __iomem *regs; 69 bool enabled; 70 /* Context save registers */ 71 u32 qepcon; 72 u32 qepflt; 73 u32 qepmax; 74 }; 75 76 static inline u32 intel_qep_readl(struct intel_qep *qep, u32 offset) 77 { 78 return readl(qep->regs + offset); 79 } 80 81 static inline void intel_qep_writel(struct intel_qep *qep, 82 u32 offset, u32 value) 83 { 84 writel(value, qep->regs + offset); 85 } 86 87 static void intel_qep_init(struct intel_qep *qep) 88 { 89 u32 reg; 90 91 reg = intel_qep_readl(qep, INTEL_QEPCON); 92 reg &= ~INTEL_QEPCON_EN; 93 intel_qep_writel(qep, INTEL_QEPCON, reg); 94 qep->enabled = false; 95 /* 96 * Make sure peripheral is disabled by flushing the write with 97 * a dummy read 98 */ 99 reg = intel_qep_readl(qep, INTEL_QEPCON); 100 101 reg &= ~(INTEL_QEPCON_OP_MODE | INTEL_QEPCON_FLT_EN); 102 reg |= INTEL_QEPCON_EDGE_A | INTEL_QEPCON_EDGE_B | 103 INTEL_QEPCON_EDGE_INDX | INTEL_QEPCON_COUNT_RST_MODE; 104 intel_qep_writel(qep, INTEL_QEPCON, reg); 105 intel_qep_writel(qep, INTEL_QEPINT_MASK, INTEL_QEPINT_MASK_ALL); 106 } 107 108 static int intel_qep_count_read(struct counter_device *counter, 109 struct counter_count *count, u64 *val) 110 { 111 struct intel_qep *const qep = counter_priv(counter); 112 113 pm_runtime_get_sync(qep->dev); 114 *val = intel_qep_readl(qep, INTEL_QEPCOUNT); 115 pm_runtime_put(qep->dev); 116 117 return 0; 118 } 119 120 static const enum counter_function intel_qep_count_functions[] = { 121 COUNTER_FUNCTION_QUADRATURE_X4, 122 }; 123 124 static int intel_qep_function_read(struct counter_device *counter, 125 struct counter_count *count, 126 enum counter_function *function) 127 { 128 *function = COUNTER_FUNCTION_QUADRATURE_X4; 129 130 return 0; 131 } 132 133 static const enum counter_synapse_action intel_qep_synapse_actions[] = { 134 COUNTER_SYNAPSE_ACTION_BOTH_EDGES, 135 }; 136 137 static int intel_qep_action_read(struct counter_device *counter, 138 struct counter_count *count, 139 struct counter_synapse *synapse, 140 enum counter_synapse_action *action) 141 { 142 *action = COUNTER_SYNAPSE_ACTION_BOTH_EDGES; 143 return 0; 144 } 145 146 static const struct counter_ops intel_qep_counter_ops = { 147 .count_read = intel_qep_count_read, 148 .function_read = intel_qep_function_read, 149 .action_read = intel_qep_action_read, 150 }; 151 152 #define INTEL_QEP_SIGNAL(_id, _name) { \ 153 .id = (_id), \ 154 .name = (_name), \ 155 } 156 157 static struct counter_signal intel_qep_signals[] = { 158 INTEL_QEP_SIGNAL(0, "Phase A"), 159 INTEL_QEP_SIGNAL(1, "Phase B"), 160 INTEL_QEP_SIGNAL(2, "Index"), 161 }; 162 163 #define INTEL_QEP_SYNAPSE(_signal_id) { \ 164 .actions_list = intel_qep_synapse_actions, \ 165 .num_actions = ARRAY_SIZE(intel_qep_synapse_actions), \ 166 .signal = &intel_qep_signals[(_signal_id)], \ 167 } 168 169 static struct counter_synapse intel_qep_count_synapses[] = { 170 INTEL_QEP_SYNAPSE(0), 171 INTEL_QEP_SYNAPSE(1), 172 INTEL_QEP_SYNAPSE(2), 173 }; 174 175 static int intel_qep_ceiling_read(struct counter_device *counter, 176 struct counter_count *count, u64 *ceiling) 177 { 178 struct intel_qep *qep = counter_priv(counter); 179 180 pm_runtime_get_sync(qep->dev); 181 *ceiling = intel_qep_readl(qep, INTEL_QEPMAX); 182 pm_runtime_put(qep->dev); 183 184 return 0; 185 } 186 187 static int intel_qep_ceiling_write(struct counter_device *counter, 188 struct counter_count *count, u64 max) 189 { 190 struct intel_qep *qep = counter_priv(counter); 191 int ret = 0; 192 193 /* Intel QEP ceiling configuration only supports 32-bit values */ 194 if (max != (u32)max) 195 return -ERANGE; 196 197 mutex_lock(&qep->lock); 198 if (qep->enabled) { 199 ret = -EBUSY; 200 goto out; 201 } 202 203 pm_runtime_get_sync(qep->dev); 204 intel_qep_writel(qep, INTEL_QEPMAX, max); 205 pm_runtime_put(qep->dev); 206 207 out: 208 mutex_unlock(&qep->lock); 209 return ret; 210 } 211 212 static int intel_qep_enable_read(struct counter_device *counter, 213 struct counter_count *count, u8 *enable) 214 { 215 struct intel_qep *qep = counter_priv(counter); 216 217 *enable = qep->enabled; 218 219 return 0; 220 } 221 222 static int intel_qep_enable_write(struct counter_device *counter, 223 struct counter_count *count, u8 val) 224 { 225 struct intel_qep *qep = counter_priv(counter); 226 u32 reg; 227 bool changed; 228 229 mutex_lock(&qep->lock); 230 changed = val ^ qep->enabled; 231 if (!changed) 232 goto out; 233 234 pm_runtime_get_sync(qep->dev); 235 reg = intel_qep_readl(qep, INTEL_QEPCON); 236 if (val) { 237 /* Enable peripheral and keep runtime PM always on */ 238 reg |= INTEL_QEPCON_EN; 239 pm_runtime_get_noresume(qep->dev); 240 } else { 241 /* Let runtime PM be idle and disable peripheral */ 242 pm_runtime_put_noidle(qep->dev); 243 reg &= ~INTEL_QEPCON_EN; 244 } 245 intel_qep_writel(qep, INTEL_QEPCON, reg); 246 pm_runtime_put(qep->dev); 247 qep->enabled = val; 248 249 out: 250 mutex_unlock(&qep->lock); 251 return 0; 252 } 253 254 static int intel_qep_spike_filter_ns_read(struct counter_device *counter, 255 struct counter_count *count, 256 u64 *length) 257 { 258 struct intel_qep *qep = counter_priv(counter); 259 u32 reg; 260 261 pm_runtime_get_sync(qep->dev); 262 reg = intel_qep_readl(qep, INTEL_QEPCON); 263 if (!(reg & INTEL_QEPCON_FLT_EN)) { 264 pm_runtime_put(qep->dev); 265 return 0; 266 } 267 reg = INTEL_QEPFLT_MAX_COUNT(intel_qep_readl(qep, INTEL_QEPFLT)); 268 pm_runtime_put(qep->dev); 269 270 *length = (reg + 2) * INTEL_QEP_CLK_PERIOD_NS; 271 272 return 0; 273 } 274 275 static int intel_qep_spike_filter_ns_write(struct counter_device *counter, 276 struct counter_count *count, 277 u64 length) 278 { 279 struct intel_qep *qep = counter_priv(counter); 280 u32 reg; 281 bool enable; 282 int ret = 0; 283 284 /* 285 * Spike filter length is (MAX_COUNT + 2) clock periods. 286 * Disable filter when userspace writes 0, enable for valid 287 * nanoseconds values and error out otherwise. 288 */ 289 do_div(length, INTEL_QEP_CLK_PERIOD_NS); 290 if (length == 0) { 291 enable = false; 292 length = 0; 293 } else if (length >= 2) { 294 enable = true; 295 length -= 2; 296 } else { 297 return -EINVAL; 298 } 299 300 if (length > INTEL_QEPFLT_MAX_COUNT(length)) 301 return -ERANGE; 302 303 mutex_lock(&qep->lock); 304 if (qep->enabled) { 305 ret = -EBUSY; 306 goto out; 307 } 308 309 pm_runtime_get_sync(qep->dev); 310 reg = intel_qep_readl(qep, INTEL_QEPCON); 311 if (enable) 312 reg |= INTEL_QEPCON_FLT_EN; 313 else 314 reg &= ~INTEL_QEPCON_FLT_EN; 315 intel_qep_writel(qep, INTEL_QEPFLT, length); 316 intel_qep_writel(qep, INTEL_QEPCON, reg); 317 pm_runtime_put(qep->dev); 318 319 out: 320 mutex_unlock(&qep->lock); 321 return ret; 322 } 323 324 static int intel_qep_preset_enable_read(struct counter_device *counter, 325 struct counter_count *count, 326 u8 *preset_enable) 327 { 328 struct intel_qep *qep = counter_priv(counter); 329 u32 reg; 330 331 pm_runtime_get_sync(qep->dev); 332 reg = intel_qep_readl(qep, INTEL_QEPCON); 333 pm_runtime_put(qep->dev); 334 335 *preset_enable = !(reg & INTEL_QEPCON_COUNT_RST_MODE); 336 337 return 0; 338 } 339 340 static int intel_qep_preset_enable_write(struct counter_device *counter, 341 struct counter_count *count, u8 val) 342 { 343 struct intel_qep *qep = counter_priv(counter); 344 u32 reg; 345 int ret = 0; 346 347 mutex_lock(&qep->lock); 348 if (qep->enabled) { 349 ret = -EBUSY; 350 goto out; 351 } 352 353 pm_runtime_get_sync(qep->dev); 354 reg = intel_qep_readl(qep, INTEL_QEPCON); 355 if (val) 356 reg &= ~INTEL_QEPCON_COUNT_RST_MODE; 357 else 358 reg |= INTEL_QEPCON_COUNT_RST_MODE; 359 360 intel_qep_writel(qep, INTEL_QEPCON, reg); 361 pm_runtime_put(qep->dev); 362 363 out: 364 mutex_unlock(&qep->lock); 365 366 return ret; 367 } 368 369 static struct counter_comp intel_qep_count_ext[] = { 370 COUNTER_COMP_ENABLE(intel_qep_enable_read, intel_qep_enable_write), 371 COUNTER_COMP_CEILING(intel_qep_ceiling_read, intel_qep_ceiling_write), 372 COUNTER_COMP_PRESET_ENABLE(intel_qep_preset_enable_read, 373 intel_qep_preset_enable_write), 374 COUNTER_COMP_COUNT_U64("spike_filter_ns", 375 intel_qep_spike_filter_ns_read, 376 intel_qep_spike_filter_ns_write), 377 }; 378 379 static struct counter_count intel_qep_counter_count[] = { 380 { 381 .id = 0, 382 .name = "Channel 1 Count", 383 .functions_list = intel_qep_count_functions, 384 .num_functions = ARRAY_SIZE(intel_qep_count_functions), 385 .synapses = intel_qep_count_synapses, 386 .num_synapses = ARRAY_SIZE(intel_qep_count_synapses), 387 .ext = intel_qep_count_ext, 388 .num_ext = ARRAY_SIZE(intel_qep_count_ext), 389 }, 390 }; 391 392 static int intel_qep_probe(struct pci_dev *pci, const struct pci_device_id *id) 393 { 394 struct counter_device *counter; 395 struct intel_qep *qep; 396 struct device *dev = &pci->dev; 397 void __iomem *regs; 398 int ret; 399 400 counter = devm_counter_alloc(dev, sizeof(*qep)); 401 if (!counter) 402 return -ENOMEM; 403 qep = counter_priv(counter); 404 405 ret = pcim_enable_device(pci); 406 if (ret) 407 return ret; 408 409 pci_set_master(pci); 410 411 ret = pcim_iomap_regions(pci, BIT(0), pci_name(pci)); 412 if (ret) 413 return ret; 414 415 regs = pcim_iomap_table(pci)[0]; 416 if (!regs) 417 return -ENOMEM; 418 419 qep->dev = dev; 420 qep->regs = regs; 421 mutex_init(&qep->lock); 422 423 intel_qep_init(qep); 424 pci_set_drvdata(pci, qep); 425 426 counter->name = pci_name(pci); 427 counter->parent = dev; 428 counter->ops = &intel_qep_counter_ops; 429 counter->counts = intel_qep_counter_count; 430 counter->num_counts = ARRAY_SIZE(intel_qep_counter_count); 431 counter->signals = intel_qep_signals; 432 counter->num_signals = ARRAY_SIZE(intel_qep_signals); 433 qep->enabled = false; 434 435 pm_runtime_put(dev); 436 pm_runtime_allow(dev); 437 438 ret = devm_counter_add(&pci->dev, counter); 439 if (ret < 0) 440 return dev_err_probe(&pci->dev, ret, "Failed to add counter\n"); 441 442 return 0; 443 } 444 445 static void intel_qep_remove(struct pci_dev *pci) 446 { 447 struct intel_qep *qep = pci_get_drvdata(pci); 448 struct device *dev = &pci->dev; 449 450 pm_runtime_forbid(dev); 451 if (!qep->enabled) 452 pm_runtime_get(dev); 453 454 intel_qep_writel(qep, INTEL_QEPCON, 0); 455 } 456 457 static int __maybe_unused intel_qep_suspend(struct device *dev) 458 { 459 struct pci_dev *pdev = to_pci_dev(dev); 460 struct intel_qep *qep = pci_get_drvdata(pdev); 461 462 qep->qepcon = intel_qep_readl(qep, INTEL_QEPCON); 463 qep->qepflt = intel_qep_readl(qep, INTEL_QEPFLT); 464 qep->qepmax = intel_qep_readl(qep, INTEL_QEPMAX); 465 466 return 0; 467 } 468 469 static int __maybe_unused intel_qep_resume(struct device *dev) 470 { 471 struct pci_dev *pdev = to_pci_dev(dev); 472 struct intel_qep *qep = pci_get_drvdata(pdev); 473 474 /* 475 * Make sure peripheral is disabled when restoring registers and 476 * control register bits that are writable only when the peripheral 477 * is disabled 478 */ 479 intel_qep_writel(qep, INTEL_QEPCON, 0); 480 intel_qep_readl(qep, INTEL_QEPCON); 481 482 intel_qep_writel(qep, INTEL_QEPFLT, qep->qepflt); 483 intel_qep_writel(qep, INTEL_QEPMAX, qep->qepmax); 484 intel_qep_writel(qep, INTEL_QEPINT_MASK, INTEL_QEPINT_MASK_ALL); 485 486 /* Restore all other control register bits except enable status */ 487 intel_qep_writel(qep, INTEL_QEPCON, qep->qepcon & ~INTEL_QEPCON_EN); 488 intel_qep_readl(qep, INTEL_QEPCON); 489 490 /* Restore enable status */ 491 intel_qep_writel(qep, INTEL_QEPCON, qep->qepcon); 492 493 return 0; 494 } 495 496 static UNIVERSAL_DEV_PM_OPS(intel_qep_pm_ops, 497 intel_qep_suspend, intel_qep_resume, NULL); 498 499 static const struct pci_device_id intel_qep_id_table[] = { 500 /* EHL */ 501 { PCI_VDEVICE(INTEL, 0x4bc3), }, 502 { PCI_VDEVICE(INTEL, 0x4b81), }, 503 { PCI_VDEVICE(INTEL, 0x4b82), }, 504 { PCI_VDEVICE(INTEL, 0x4b83), }, 505 { } /* Terminating Entry */ 506 }; 507 MODULE_DEVICE_TABLE(pci, intel_qep_id_table); 508 509 static struct pci_driver intel_qep_driver = { 510 .name = "intel-qep", 511 .id_table = intel_qep_id_table, 512 .probe = intel_qep_probe, 513 .remove = intel_qep_remove, 514 .driver = { 515 .pm = &intel_qep_pm_ops, 516 } 517 }; 518 519 module_pci_driver(intel_qep_driver); 520 521 MODULE_AUTHOR("Felipe Balbi (Intel)"); 522 MODULE_AUTHOR("Jarkko Nikula <jarkko.nikula@linux.intel.com>"); 523 MODULE_AUTHOR("Raymond Tan <raymond.tan@intel.com>"); 524 MODULE_LICENSE("GPL"); 525 MODULE_DESCRIPTION("Intel Quadrature Encoder Peripheral driver"); 526 MODULE_IMPORT_NS(COUNTER); 527