1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * RackMac vu-meter driver 4 * 5 * (c) Copyright 2006 Benjamin Herrenschmidt, IBM Corp. 6 * <benh@kernel.crashing.org> 7 * 8 * Support the CPU-meter LEDs of the Xserve G5 9 * 10 * TODO: Implement PWM to do variable intensity and provide userland 11 * interface for fun. Also, the CPU-meter could be made nicer by being 12 * a bit less "immediate" but giving instead a more average load over 13 * time. Patches welcome :-) 14 */ 15 #undef DEBUG 16 17 #include <linux/types.h> 18 #include <linux/kernel.h> 19 #include <linux/slab.h> 20 #include <linux/device.h> 21 #include <linux/interrupt.h> 22 #include <linux/module.h> 23 #include <linux/pci.h> 24 #include <linux/dma-mapping.h> 25 #include <linux/kernel_stat.h> 26 #include <linux/of_address.h> 27 #include <linux/of_irq.h> 28 29 #include <asm/io.h> 30 #include <asm/machdep.h> 31 #include <asm/pmac_feature.h> 32 #include <asm/dbdma.h> 33 #include <asm/macio.h> 34 #include <asm/keylargo.h> 35 36 /* Number of samples in a sample buffer */ 37 #define SAMPLE_COUNT 256 38 39 /* CPU meter sampling rate in ms */ 40 #define CPU_SAMPLING_RATE 250 41 42 struct rackmeter_dma { 43 struct dbdma_cmd cmd[4] ____cacheline_aligned; 44 u32 mark ____cacheline_aligned; 45 u32 buf1[SAMPLE_COUNT] ____cacheline_aligned; 46 u32 buf2[SAMPLE_COUNT] ____cacheline_aligned; 47 } ____cacheline_aligned; 48 49 struct rackmeter_cpu { 50 struct delayed_work sniffer; 51 struct rackmeter *rm; 52 u64 prev_wall; 53 u64 prev_idle; 54 int zero; 55 } ____cacheline_aligned; 56 57 struct rackmeter { 58 struct macio_dev *mdev; 59 unsigned int irq; 60 struct device_node *i2s; 61 u8 *ubuf; 62 struct dbdma_regs __iomem *dma_regs; 63 void __iomem *i2s_regs; 64 dma_addr_t dma_buf_p; 65 struct rackmeter_dma *dma_buf_v; 66 int stale_irq; 67 struct rackmeter_cpu cpu[2]; 68 int paused; 69 struct mutex sem; 70 }; 71 72 /* To be set as a tunable */ 73 static int rackmeter_ignore_nice; 74 75 /* This GPIO is whacked by the OS X driver when initializing */ 76 #define RACKMETER_MAGIC_GPIO 0x78 77 78 /* This is copied from cpufreq_ondemand, maybe we should put it in 79 * a common header somewhere 80 */ 81 static inline u64 get_cpu_idle_time(unsigned int cpu) 82 { 83 struct kernel_cpustat *kcpustat = &kcpustat_cpu(cpu); 84 u64 retval; 85 86 retval = kcpustat->cpustat[CPUTIME_IDLE] + 87 kcpustat->cpustat[CPUTIME_IOWAIT]; 88 89 if (rackmeter_ignore_nice) 90 retval += kcpustat_field(kcpustat, CPUTIME_NICE, cpu); 91 92 return retval; 93 } 94 95 static void rackmeter_setup_i2s(struct rackmeter *rm) 96 { 97 struct macio_chip *macio = rm->mdev->bus->chip; 98 99 /* First whack magic GPIO */ 100 pmac_call_feature(PMAC_FTR_WRITE_GPIO, NULL, RACKMETER_MAGIC_GPIO, 5); 101 102 103 /* Call feature code to enable the sound channel and the proper 104 * clock sources 105 */ 106 pmac_call_feature(PMAC_FTR_SOUND_CHIP_ENABLE, rm->i2s, 0, 1); 107 108 /* Power i2s and stop i2s clock. We whack MacIO FCRs directly for now. 109 * This is a bit racy, thus we should add new platform functions to 110 * handle that. snd-aoa needs that too 111 */ 112 MACIO_BIS(KEYLARGO_FCR1, KL1_I2S0_ENABLE); 113 MACIO_BIC(KEYLARGO_FCR1, KL1_I2S0_CLK_ENABLE_BIT); 114 (void)MACIO_IN32(KEYLARGO_FCR1); 115 udelay(10); 116 117 /* Then setup i2s. For now, we use the same magic value that 118 * the OS X driver seems to use. We might want to play around 119 * with the clock divisors later 120 */ 121 out_le32(rm->i2s_regs + 0x10, 0x01fa0000); 122 (void)in_le32(rm->i2s_regs + 0x10); 123 udelay(10); 124 125 /* Fully restart i2s*/ 126 MACIO_BIS(KEYLARGO_FCR1, KL1_I2S0_CELL_ENABLE | 127 KL1_I2S0_CLK_ENABLE_BIT); 128 (void)MACIO_IN32(KEYLARGO_FCR1); 129 udelay(10); 130 } 131 132 static void rackmeter_set_default_pattern(struct rackmeter *rm) 133 { 134 int i; 135 136 for (i = 0; i < 16; i++) { 137 if (i < 8) 138 rm->ubuf[i] = (i & 1) * 255; 139 else 140 rm->ubuf[i] = ((~i) & 1) * 255; 141 } 142 } 143 144 static void rackmeter_do_pause(struct rackmeter *rm, int pause) 145 { 146 struct rackmeter_dma *rdma = rm->dma_buf_v; 147 148 pr_debug("rackmeter: %s\n", pause ? "paused" : "started"); 149 150 rm->paused = pause; 151 if (pause) { 152 DBDMA_DO_STOP(rm->dma_regs); 153 return; 154 } 155 memset(rdma->buf1, 0, sizeof(rdma->buf1)); 156 memset(rdma->buf2, 0, sizeof(rdma->buf2)); 157 158 rm->dma_buf_v->mark = 0; 159 160 mb(); 161 out_le32(&rm->dma_regs->cmdptr_hi, 0); 162 out_le32(&rm->dma_regs->cmdptr, rm->dma_buf_p); 163 out_le32(&rm->dma_regs->control, (RUN << 16) | RUN); 164 } 165 166 static void rackmeter_setup_dbdma(struct rackmeter *rm) 167 { 168 struct rackmeter_dma *db = rm->dma_buf_v; 169 struct dbdma_cmd *cmd = db->cmd; 170 171 /* Make sure dbdma is reset */ 172 DBDMA_DO_RESET(rm->dma_regs); 173 174 pr_debug("rackmeter: mark offset=0x%zx\n", 175 offsetof(struct rackmeter_dma, mark)); 176 pr_debug("rackmeter: buf1 offset=0x%zx\n", 177 offsetof(struct rackmeter_dma, buf1)); 178 pr_debug("rackmeter: buf2 offset=0x%zx\n", 179 offsetof(struct rackmeter_dma, buf2)); 180 181 /* Prepare 4 dbdma commands for the 2 buffers */ 182 memset(cmd, 0, 4 * sizeof(struct dbdma_cmd)); 183 cmd->req_count = cpu_to_le16(4); 184 cmd->command = cpu_to_le16(STORE_WORD | INTR_ALWAYS | KEY_SYSTEM); 185 cmd->phy_addr = cpu_to_le32(rm->dma_buf_p + 186 offsetof(struct rackmeter_dma, mark)); 187 cmd->cmd_dep = cpu_to_le32(0x02000000); 188 cmd++; 189 190 cmd->req_count = cpu_to_le16(SAMPLE_COUNT * 4); 191 cmd->command = cpu_to_le16(OUTPUT_MORE); 192 cmd->phy_addr = cpu_to_le32(rm->dma_buf_p + 193 offsetof(struct rackmeter_dma, buf1)); 194 cmd++; 195 196 cmd->req_count = cpu_to_le16(4); 197 cmd->command = cpu_to_le16(STORE_WORD | INTR_ALWAYS | KEY_SYSTEM); 198 cmd->phy_addr = cpu_to_le32(rm->dma_buf_p + 199 offsetof(struct rackmeter_dma, mark)); 200 cmd->cmd_dep = cpu_to_le32(0x01000000); 201 cmd++; 202 203 cmd->req_count = cpu_to_le16(SAMPLE_COUNT * 4); 204 cmd->command = cpu_to_le16(OUTPUT_MORE | BR_ALWAYS); 205 cmd->phy_addr = cpu_to_le32(rm->dma_buf_p + 206 offsetof(struct rackmeter_dma, buf2)); 207 cmd->cmd_dep = cpu_to_le32(rm->dma_buf_p); 208 209 rackmeter_do_pause(rm, 0); 210 } 211 212 static void rackmeter_do_timer(struct work_struct *work) 213 { 214 struct rackmeter_cpu *rcpu = 215 container_of(work, struct rackmeter_cpu, sniffer.work); 216 struct rackmeter *rm = rcpu->rm; 217 unsigned int cpu = smp_processor_id(); 218 u64 cur_nsecs, total_idle_nsecs; 219 u64 total_nsecs, idle_nsecs; 220 int i, offset, load, cumm, pause; 221 222 cur_nsecs = jiffies64_to_nsecs(get_jiffies_64()); 223 total_nsecs = cur_nsecs - rcpu->prev_wall; 224 rcpu->prev_wall = cur_nsecs; 225 226 total_idle_nsecs = get_cpu_idle_time(cpu); 227 idle_nsecs = total_idle_nsecs - rcpu->prev_idle; 228 idle_nsecs = min(idle_nsecs, total_nsecs); 229 rcpu->prev_idle = total_idle_nsecs; 230 231 /* We do a very dumb calculation to update the LEDs for now, 232 * we'll do better once we have actual PWM implemented 233 */ 234 load = div64_u64(9 * (total_nsecs - idle_nsecs), total_nsecs); 235 236 offset = cpu << 3; 237 cumm = 0; 238 for (i = 0; i < 8; i++) { 239 u8 ub = (load > i) ? 0xff : 0; 240 rm->ubuf[i + offset] = ub; 241 cumm |= ub; 242 } 243 rcpu->zero = (cumm == 0); 244 245 /* Now check if LEDs are all 0, we can stop DMA */ 246 pause = (rm->cpu[0].zero && rm->cpu[1].zero); 247 if (pause != rm->paused) { 248 mutex_lock(&rm->sem); 249 pause = (rm->cpu[0].zero && rm->cpu[1].zero); 250 rackmeter_do_pause(rm, pause); 251 mutex_unlock(&rm->sem); 252 } 253 schedule_delayed_work_on(cpu, &rcpu->sniffer, 254 msecs_to_jiffies(CPU_SAMPLING_RATE)); 255 } 256 257 static void rackmeter_init_cpu_sniffer(struct rackmeter *rm) 258 { 259 unsigned int cpu; 260 261 /* This driver works only with 1 or 2 CPUs numbered 0 and 1, 262 * but that's really all we have on Apple Xserve. It doesn't 263 * play very nice with CPU hotplug neither but we don't do that 264 * on those machines yet 265 */ 266 267 rm->cpu[0].rm = rm; 268 INIT_DELAYED_WORK(&rm->cpu[0].sniffer, rackmeter_do_timer); 269 rm->cpu[1].rm = rm; 270 INIT_DELAYED_WORK(&rm->cpu[1].sniffer, rackmeter_do_timer); 271 272 for_each_online_cpu(cpu) { 273 struct rackmeter_cpu *rcpu; 274 275 if (cpu > 1) 276 continue; 277 rcpu = &rm->cpu[cpu]; 278 rcpu->prev_idle = get_cpu_idle_time(cpu); 279 rcpu->prev_wall = jiffies64_to_nsecs(get_jiffies_64()); 280 schedule_delayed_work_on(cpu, &rm->cpu[cpu].sniffer, 281 msecs_to_jiffies(CPU_SAMPLING_RATE)); 282 } 283 } 284 285 static void rackmeter_stop_cpu_sniffer(struct rackmeter *rm) 286 { 287 cancel_delayed_work_sync(&rm->cpu[0].sniffer); 288 cancel_delayed_work_sync(&rm->cpu[1].sniffer); 289 } 290 291 static int rackmeter_setup(struct rackmeter *rm) 292 { 293 pr_debug("rackmeter: setting up i2s..\n"); 294 rackmeter_setup_i2s(rm); 295 296 pr_debug("rackmeter: setting up default pattern..\n"); 297 rackmeter_set_default_pattern(rm); 298 299 pr_debug("rackmeter: setting up dbdma..\n"); 300 rackmeter_setup_dbdma(rm); 301 302 pr_debug("rackmeter: start CPU measurements..\n"); 303 rackmeter_init_cpu_sniffer(rm); 304 305 printk(KERN_INFO "RackMeter initialized\n"); 306 307 return 0; 308 } 309 310 /* XXX FIXME: No PWM yet, this is 0/1 */ 311 static u32 rackmeter_calc_sample(struct rackmeter *rm, unsigned int index) 312 { 313 int led; 314 u32 sample = 0; 315 316 for (led = 0; led < 16; led++) { 317 sample >>= 1; 318 sample |= ((rm->ubuf[led] >= 0x80) << 15); 319 } 320 return (sample << 17) | (sample >> 15); 321 } 322 323 static irqreturn_t rackmeter_irq(int irq, void *arg) 324 { 325 struct rackmeter *rm = arg; 326 struct rackmeter_dma *db = rm->dma_buf_v; 327 unsigned int mark, i; 328 u32 *buf; 329 330 /* Flush PCI buffers with an MMIO read. Maybe we could actually 331 * check the status one day ... in case things go wrong, though 332 * this never happened to me 333 */ 334 (void)in_le32(&rm->dma_regs->status); 335 336 /* Make sure the CPU gets us in order */ 337 rmb(); 338 339 /* Read mark */ 340 mark = db->mark; 341 if (mark != 1 && mark != 2) { 342 printk(KERN_WARNING "rackmeter: Incorrect DMA mark 0x%08x\n", 343 mark); 344 /* We allow for 3 errors like that (stale DBDMA irqs) */ 345 if (++rm->stale_irq > 3) { 346 printk(KERN_ERR "rackmeter: Too many errors," 347 " stopping DMA\n"); 348 DBDMA_DO_RESET(rm->dma_regs); 349 } 350 return IRQ_HANDLED; 351 } 352 353 /* Next buffer we need to fill is mark value */ 354 buf = mark == 1 ? db->buf1 : db->buf2; 355 356 /* Fill it now. This routine converts the 8 bits depth sample array 357 * into the PWM bitmap for each LED. 358 */ 359 for (i = 0; i < SAMPLE_COUNT; i++) 360 buf[i] = rackmeter_calc_sample(rm, i); 361 362 363 return IRQ_HANDLED; 364 } 365 366 static int rackmeter_probe(struct macio_dev* mdev, 367 const struct of_device_id *match) 368 { 369 struct device_node *i2s = NULL, *np = NULL; 370 struct rackmeter *rm = NULL; 371 struct resource ri2s, rdma; 372 int rc = -ENODEV; 373 374 pr_debug("rackmeter_probe()\n"); 375 376 /* Get i2s-a node */ 377 for_each_child_of_node(mdev->ofdev.dev.of_node, i2s) 378 if (of_node_name_eq(i2s, "i2s-a")) 379 break; 380 381 if (i2s == NULL) { 382 pr_debug(" i2s-a child not found\n"); 383 goto bail; 384 } 385 /* Get lightshow or virtual sound */ 386 for_each_child_of_node(i2s, np) { 387 if (of_node_name_eq(np, "lightshow")) 388 break; 389 if (of_node_name_eq(np, "sound") && 390 of_property_present(np, "virtual")) 391 break; 392 } 393 if (np == NULL) { 394 pr_debug(" lightshow or sound+virtual child not found\n"); 395 goto bail; 396 } 397 398 /* Create and initialize our instance data */ 399 rm = kzalloc(sizeof(*rm), GFP_KERNEL); 400 if (rm == NULL) { 401 printk(KERN_ERR "rackmeter: failed to allocate memory !\n"); 402 rc = -ENOMEM; 403 goto bail_release; 404 } 405 rm->mdev = mdev; 406 rm->i2s = i2s; 407 mutex_init(&rm->sem); 408 dev_set_drvdata(&mdev->ofdev.dev, rm); 409 /* Check resources availability. We need at least resource 0 and 1 */ 410 #if 0 /* Use that when i2s-a is finally an mdev per-se */ 411 if (macio_resource_count(mdev) < 2 || macio_irq_count(mdev) < 2) { 412 printk(KERN_ERR 413 "rackmeter: found match but lacks resources: %pOF" 414 " (%d resources, %d interrupts)\n", 415 mdev->ofdev.dev.of_node); 416 rc = -ENXIO; 417 goto bail_free; 418 } 419 if (macio_request_resources(mdev, "rackmeter")) { 420 printk(KERN_ERR 421 "rackmeter: failed to request resources: %pOF\n", 422 mdev->ofdev.dev.of_node); 423 rc = -EBUSY; 424 goto bail_free; 425 } 426 rm->irq = macio_irq(mdev, 1); 427 #else 428 rm->irq = irq_of_parse_and_map(i2s, 1); 429 if (!rm->irq || 430 of_address_to_resource(i2s, 0, &ri2s) || 431 of_address_to_resource(i2s, 1, &rdma)) { 432 printk(KERN_ERR 433 "rackmeter: found match but lacks resources: %pOF", 434 mdev->ofdev.dev.of_node); 435 rc = -ENXIO; 436 goto bail_free; 437 } 438 #endif 439 440 pr_debug(" i2s @0x%08x\n", (unsigned int)ri2s.start); 441 pr_debug(" dma @0x%08x\n", (unsigned int)rdma.start); 442 pr_debug(" irq %d\n", rm->irq); 443 444 rm->ubuf = (u8 *)__get_free_page(GFP_KERNEL); 445 if (rm->ubuf == NULL) { 446 printk(KERN_ERR 447 "rackmeter: failed to allocate samples page !\n"); 448 rc = -ENOMEM; 449 goto bail_release; 450 } 451 452 rm->dma_buf_v = dma_alloc_coherent(&macio_get_pci_dev(mdev)->dev, 453 sizeof(struct rackmeter_dma), 454 &rm->dma_buf_p, GFP_KERNEL); 455 if (rm->dma_buf_v == NULL) { 456 printk(KERN_ERR 457 "rackmeter: failed to allocate dma buffer !\n"); 458 rc = -ENOMEM; 459 goto bail_free_samples; 460 } 461 #if 0 462 rm->i2s_regs = ioremap(macio_resource_start(mdev, 0), 0x1000); 463 #else 464 rm->i2s_regs = ioremap(ri2s.start, 0x1000); 465 #endif 466 if (rm->i2s_regs == NULL) { 467 printk(KERN_ERR 468 "rackmeter: failed to map i2s registers !\n"); 469 rc = -ENXIO; 470 goto bail_free_dma; 471 } 472 #if 0 473 rm->dma_regs = ioremap(macio_resource_start(mdev, 1), 0x100); 474 #else 475 rm->dma_regs = ioremap(rdma.start, 0x100); 476 #endif 477 if (rm->dma_regs == NULL) { 478 printk(KERN_ERR 479 "rackmeter: failed to map dma registers !\n"); 480 rc = -ENXIO; 481 goto bail_unmap_i2s; 482 } 483 484 rc = rackmeter_setup(rm); 485 if (rc) { 486 printk(KERN_ERR 487 "rackmeter: failed to initialize !\n"); 488 rc = -ENXIO; 489 goto bail_unmap_dma; 490 } 491 492 rc = request_irq(rm->irq, rackmeter_irq, 0, "rackmeter", rm); 493 if (rc != 0) { 494 printk(KERN_ERR 495 "rackmeter: failed to request interrupt !\n"); 496 goto bail_stop_dma; 497 } 498 of_node_put(np); 499 return 0; 500 501 bail_stop_dma: 502 DBDMA_DO_RESET(rm->dma_regs); 503 bail_unmap_dma: 504 iounmap(rm->dma_regs); 505 bail_unmap_i2s: 506 iounmap(rm->i2s_regs); 507 bail_free_dma: 508 dma_free_coherent(&macio_get_pci_dev(mdev)->dev, 509 sizeof(struct rackmeter_dma), 510 rm->dma_buf_v, rm->dma_buf_p); 511 bail_free_samples: 512 free_page((unsigned long)rm->ubuf); 513 bail_release: 514 #if 0 515 macio_release_resources(mdev); 516 #endif 517 bail_free: 518 kfree(rm); 519 bail: 520 of_node_put(i2s); 521 of_node_put(np); 522 dev_set_drvdata(&mdev->ofdev.dev, NULL); 523 return rc; 524 } 525 526 static int rackmeter_remove(struct macio_dev* mdev) 527 { 528 struct rackmeter *rm = dev_get_drvdata(&mdev->ofdev.dev); 529 530 /* Stop CPU sniffer timer & work queues */ 531 rackmeter_stop_cpu_sniffer(rm); 532 533 /* Clear reference to private data */ 534 dev_set_drvdata(&mdev->ofdev.dev, NULL); 535 536 /* Stop/reset dbdma */ 537 DBDMA_DO_RESET(rm->dma_regs); 538 539 /* Release the IRQ */ 540 free_irq(rm->irq, rm); 541 542 /* Unmap registers */ 543 iounmap(rm->dma_regs); 544 iounmap(rm->i2s_regs); 545 546 /* Free DMA */ 547 dma_free_coherent(&macio_get_pci_dev(mdev)->dev, 548 sizeof(struct rackmeter_dma), 549 rm->dma_buf_v, rm->dma_buf_p); 550 551 /* Free samples */ 552 free_page((unsigned long)rm->ubuf); 553 554 #if 0 555 /* Release resources */ 556 macio_release_resources(mdev); 557 #endif 558 559 /* Get rid of me */ 560 kfree(rm); 561 562 return 0; 563 } 564 565 static int rackmeter_shutdown(struct macio_dev* mdev) 566 { 567 struct rackmeter *rm = dev_get_drvdata(&mdev->ofdev.dev); 568 569 if (rm == NULL) 570 return -ENODEV; 571 572 /* Stop CPU sniffer timer & work queues */ 573 rackmeter_stop_cpu_sniffer(rm); 574 575 /* Stop/reset dbdma */ 576 DBDMA_DO_RESET(rm->dma_regs); 577 578 return 0; 579 } 580 581 static const struct of_device_id rackmeter_match[] = { 582 { .name = "i2s" }, 583 { } 584 }; 585 MODULE_DEVICE_TABLE(of, rackmeter_match); 586 587 static struct macio_driver rackmeter_driver = { 588 .driver = { 589 .name = "rackmeter", 590 .owner = THIS_MODULE, 591 .of_match_table = rackmeter_match, 592 }, 593 .probe = rackmeter_probe, 594 .remove = rackmeter_remove, 595 .shutdown = rackmeter_shutdown, 596 }; 597 598 599 static int __init rackmeter_init(void) 600 { 601 pr_debug("rackmeter_init()\n"); 602 603 return macio_register_driver(&rackmeter_driver); 604 } 605 606 static void __exit rackmeter_exit(void) 607 { 608 pr_debug("rackmeter_exit()\n"); 609 610 macio_unregister_driver(&rackmeter_driver); 611 } 612 613 module_init(rackmeter_init); 614 module_exit(rackmeter_exit); 615 616 617 MODULE_LICENSE("GPL"); 618 MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>"); 619 MODULE_DESCRIPTION("RackMeter: Support vu-meter on XServe front panel"); 620