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/prom.h> 31 #include <asm/machdep.h> 32 #include <asm/pmac_feature.h> 33 #include <asm/dbdma.h> 34 #include <asm/macio.h> 35 #include <asm/keylargo.h> 36 37 /* Number of samples in a sample buffer */ 38 #define SAMPLE_COUNT 256 39 40 /* CPU meter sampling rate in ms */ 41 #define CPU_SAMPLING_RATE 250 42 43 struct rackmeter_dma { 44 struct dbdma_cmd cmd[4] ____cacheline_aligned; 45 u32 mark ____cacheline_aligned; 46 u32 buf1[SAMPLE_COUNT] ____cacheline_aligned; 47 u32 buf2[SAMPLE_COUNT] ____cacheline_aligned; 48 } ____cacheline_aligned; 49 50 struct rackmeter_cpu { 51 struct delayed_work sniffer; 52 struct rackmeter *rm; 53 u64 prev_wall; 54 u64 prev_idle; 55 int zero; 56 } ____cacheline_aligned; 57 58 struct rackmeter { 59 struct macio_dev *mdev; 60 unsigned int irq; 61 struct device_node *i2s; 62 u8 *ubuf; 63 struct dbdma_regs __iomem *dma_regs; 64 void __iomem *i2s_regs; 65 dma_addr_t dma_buf_p; 66 struct rackmeter_dma *dma_buf_v; 67 int stale_irq; 68 struct rackmeter_cpu cpu[2]; 69 int paused; 70 struct mutex sem; 71 }; 72 73 /* To be set as a tunable */ 74 static int rackmeter_ignore_nice; 75 76 /* This GPIO is whacked by the OS X driver when initializing */ 77 #define RACKMETER_MAGIC_GPIO 0x78 78 79 /* This is copied from cpufreq_ondemand, maybe we should put it in 80 * a common header somewhere 81 */ 82 static inline u64 get_cpu_idle_time(unsigned int cpu) 83 { 84 struct kernel_cpustat *kcpustat = &kcpustat_cpu(cpu); 85 u64 retval; 86 87 retval = kcpustat->cpustat[CPUTIME_IDLE] + 88 kcpustat->cpustat[CPUTIME_IOWAIT]; 89 90 if (rackmeter_ignore_nice) 91 retval += kcpustat_field(kcpustat, CPUTIME_NICE, cpu); 92 93 return retval; 94 } 95 96 static void rackmeter_setup_i2s(struct rackmeter *rm) 97 { 98 struct macio_chip *macio = rm->mdev->bus->chip; 99 100 /* First whack magic GPIO */ 101 pmac_call_feature(PMAC_FTR_WRITE_GPIO, NULL, RACKMETER_MAGIC_GPIO, 5); 102 103 104 /* Call feature code to enable the sound channel and the proper 105 * clock sources 106 */ 107 pmac_call_feature(PMAC_FTR_SOUND_CHIP_ENABLE, rm->i2s, 0, 1); 108 109 /* Power i2s and stop i2s clock. We whack MacIO FCRs directly for now. 110 * This is a bit racy, thus we should add new platform functions to 111 * handle that. snd-aoa needs that too 112 */ 113 MACIO_BIS(KEYLARGO_FCR1, KL1_I2S0_ENABLE); 114 MACIO_BIC(KEYLARGO_FCR1, KL1_I2S0_CLK_ENABLE_BIT); 115 (void)MACIO_IN32(KEYLARGO_FCR1); 116 udelay(10); 117 118 /* Then setup i2s. For now, we use the same magic value that 119 * the OS X driver seems to use. We might want to play around 120 * with the clock divisors later 121 */ 122 out_le32(rm->i2s_regs + 0x10, 0x01fa0000); 123 (void)in_le32(rm->i2s_regs + 0x10); 124 udelay(10); 125 126 /* Fully restart i2s*/ 127 MACIO_BIS(KEYLARGO_FCR1, KL1_I2S0_CELL_ENABLE | 128 KL1_I2S0_CLK_ENABLE_BIT); 129 (void)MACIO_IN32(KEYLARGO_FCR1); 130 udelay(10); 131 } 132 133 static void rackmeter_set_default_pattern(struct rackmeter *rm) 134 { 135 int i; 136 137 for (i = 0; i < 16; i++) { 138 if (i < 8) 139 rm->ubuf[i] = (i & 1) * 255; 140 else 141 rm->ubuf[i] = ((~i) & 1) * 255; 142 } 143 } 144 145 static void rackmeter_do_pause(struct rackmeter *rm, int pause) 146 { 147 struct rackmeter_dma *rdma = rm->dma_buf_v; 148 149 pr_debug("rackmeter: %s\n", pause ? "paused" : "started"); 150 151 rm->paused = pause; 152 if (pause) { 153 DBDMA_DO_STOP(rm->dma_regs); 154 return; 155 } 156 memset(rdma->buf1, 0, sizeof(rdma->buf1)); 157 memset(rdma->buf2, 0, sizeof(rdma->buf2)); 158 159 rm->dma_buf_v->mark = 0; 160 161 mb(); 162 out_le32(&rm->dma_regs->cmdptr_hi, 0); 163 out_le32(&rm->dma_regs->cmdptr, rm->dma_buf_p); 164 out_le32(&rm->dma_regs->control, (RUN << 16) | RUN); 165 } 166 167 static void rackmeter_setup_dbdma(struct rackmeter *rm) 168 { 169 struct rackmeter_dma *db = rm->dma_buf_v; 170 struct dbdma_cmd *cmd = db->cmd; 171 172 /* Make sure dbdma is reset */ 173 DBDMA_DO_RESET(rm->dma_regs); 174 175 pr_debug("rackmeter: mark offset=0x%zx\n", 176 offsetof(struct rackmeter_dma, mark)); 177 pr_debug("rackmeter: buf1 offset=0x%zx\n", 178 offsetof(struct rackmeter_dma, buf1)); 179 pr_debug("rackmeter: buf2 offset=0x%zx\n", 180 offsetof(struct rackmeter_dma, buf2)); 181 182 /* Prepare 4 dbdma commands for the 2 buffers */ 183 memset(cmd, 0, 4 * sizeof(struct dbdma_cmd)); 184 cmd->req_count = cpu_to_le16(4); 185 cmd->command = cpu_to_le16(STORE_WORD | INTR_ALWAYS | KEY_SYSTEM); 186 cmd->phy_addr = cpu_to_le32(rm->dma_buf_p + 187 offsetof(struct rackmeter_dma, mark)); 188 cmd->cmd_dep = cpu_to_le32(0x02000000); 189 cmd++; 190 191 cmd->req_count = cpu_to_le16(SAMPLE_COUNT * 4); 192 cmd->command = cpu_to_le16(OUTPUT_MORE); 193 cmd->phy_addr = cpu_to_le32(rm->dma_buf_p + 194 offsetof(struct rackmeter_dma, buf1)); 195 cmd++; 196 197 cmd->req_count = cpu_to_le16(4); 198 cmd->command = cpu_to_le16(STORE_WORD | INTR_ALWAYS | KEY_SYSTEM); 199 cmd->phy_addr = cpu_to_le32(rm->dma_buf_p + 200 offsetof(struct rackmeter_dma, mark)); 201 cmd->cmd_dep = cpu_to_le32(0x01000000); 202 cmd++; 203 204 cmd->req_count = cpu_to_le16(SAMPLE_COUNT * 4); 205 cmd->command = cpu_to_le16(OUTPUT_MORE | BR_ALWAYS); 206 cmd->phy_addr = cpu_to_le32(rm->dma_buf_p + 207 offsetof(struct rackmeter_dma, buf2)); 208 cmd->cmd_dep = cpu_to_le32(rm->dma_buf_p); 209 210 rackmeter_do_pause(rm, 0); 211 } 212 213 static void rackmeter_do_timer(struct work_struct *work) 214 { 215 struct rackmeter_cpu *rcpu = 216 container_of(work, struct rackmeter_cpu, sniffer.work); 217 struct rackmeter *rm = rcpu->rm; 218 unsigned int cpu = smp_processor_id(); 219 u64 cur_nsecs, total_idle_nsecs; 220 u64 total_nsecs, idle_nsecs; 221 int i, offset, load, cumm, pause; 222 223 cur_nsecs = jiffies64_to_nsecs(get_jiffies_64()); 224 total_nsecs = cur_nsecs - rcpu->prev_wall; 225 rcpu->prev_wall = cur_nsecs; 226 227 total_idle_nsecs = get_cpu_idle_time(cpu); 228 idle_nsecs = total_idle_nsecs - rcpu->prev_idle; 229 idle_nsecs = min(idle_nsecs, total_nsecs); 230 rcpu->prev_idle = total_idle_nsecs; 231 232 /* We do a very dumb calculation to update the LEDs for now, 233 * we'll do better once we have actual PWM implemented 234 */ 235 load = div64_u64(9 * (total_nsecs - idle_nsecs), total_nsecs); 236 237 offset = cpu << 3; 238 cumm = 0; 239 for (i = 0; i < 8; i++) { 240 u8 ub = (load > i) ? 0xff : 0; 241 rm->ubuf[i + offset] = ub; 242 cumm |= ub; 243 } 244 rcpu->zero = (cumm == 0); 245 246 /* Now check if LEDs are all 0, we can stop DMA */ 247 pause = (rm->cpu[0].zero && rm->cpu[1].zero); 248 if (pause != rm->paused) { 249 mutex_lock(&rm->sem); 250 pause = (rm->cpu[0].zero && rm->cpu[1].zero); 251 rackmeter_do_pause(rm, pause); 252 mutex_unlock(&rm->sem); 253 } 254 schedule_delayed_work_on(cpu, &rcpu->sniffer, 255 msecs_to_jiffies(CPU_SAMPLING_RATE)); 256 } 257 258 static void rackmeter_init_cpu_sniffer(struct rackmeter *rm) 259 { 260 unsigned int cpu; 261 262 /* This driver works only with 1 or 2 CPUs numbered 0 and 1, 263 * but that's really all we have on Apple Xserve. It doesn't 264 * play very nice with CPU hotplug neither but we don't do that 265 * on those machines yet 266 */ 267 268 rm->cpu[0].rm = rm; 269 INIT_DELAYED_WORK(&rm->cpu[0].sniffer, rackmeter_do_timer); 270 rm->cpu[1].rm = rm; 271 INIT_DELAYED_WORK(&rm->cpu[1].sniffer, rackmeter_do_timer); 272 273 for_each_online_cpu(cpu) { 274 struct rackmeter_cpu *rcpu; 275 276 if (cpu > 1) 277 continue; 278 rcpu = &rm->cpu[cpu]; 279 rcpu->prev_idle = get_cpu_idle_time(cpu); 280 rcpu->prev_wall = jiffies64_to_nsecs(get_jiffies_64()); 281 schedule_delayed_work_on(cpu, &rm->cpu[cpu].sniffer, 282 msecs_to_jiffies(CPU_SAMPLING_RATE)); 283 } 284 } 285 286 static void rackmeter_stop_cpu_sniffer(struct rackmeter *rm) 287 { 288 cancel_delayed_work_sync(&rm->cpu[0].sniffer); 289 cancel_delayed_work_sync(&rm->cpu[1].sniffer); 290 } 291 292 static int rackmeter_setup(struct rackmeter *rm) 293 { 294 pr_debug("rackmeter: setting up i2s..\n"); 295 rackmeter_setup_i2s(rm); 296 297 pr_debug("rackmeter: setting up default pattern..\n"); 298 rackmeter_set_default_pattern(rm); 299 300 pr_debug("rackmeter: setting up dbdma..\n"); 301 rackmeter_setup_dbdma(rm); 302 303 pr_debug("rackmeter: start CPU measurements..\n"); 304 rackmeter_init_cpu_sniffer(rm); 305 306 printk(KERN_INFO "RackMeter initialized\n"); 307 308 return 0; 309 } 310 311 /* XXX FIXME: No PWM yet, this is 0/1 */ 312 static u32 rackmeter_calc_sample(struct rackmeter *rm, unsigned int index) 313 { 314 int led; 315 u32 sample = 0; 316 317 for (led = 0; led < 16; led++) { 318 sample >>= 1; 319 sample |= ((rm->ubuf[led] >= 0x80) << 15); 320 } 321 return (sample << 17) | (sample >> 15); 322 } 323 324 static irqreturn_t rackmeter_irq(int irq, void *arg) 325 { 326 struct rackmeter *rm = arg; 327 struct rackmeter_dma *db = rm->dma_buf_v; 328 unsigned int mark, i; 329 u32 *buf; 330 331 /* Flush PCI buffers with an MMIO read. Maybe we could actually 332 * check the status one day ... in case things go wrong, though 333 * this never happened to me 334 */ 335 (void)in_le32(&rm->dma_regs->status); 336 337 /* Make sure the CPU gets us in order */ 338 rmb(); 339 340 /* Read mark */ 341 mark = db->mark; 342 if (mark != 1 && mark != 2) { 343 printk(KERN_WARNING "rackmeter: Incorrect DMA mark 0x%08x\n", 344 mark); 345 /* We allow for 3 errors like that (stale DBDMA irqs) */ 346 if (++rm->stale_irq > 3) { 347 printk(KERN_ERR "rackmeter: Too many errors," 348 " stopping DMA\n"); 349 DBDMA_DO_RESET(rm->dma_regs); 350 } 351 return IRQ_HANDLED; 352 } 353 354 /* Next buffer we need to fill is mark value */ 355 buf = mark == 1 ? db->buf1 : db->buf2; 356 357 /* Fill it now. This routine converts the 8 bits depth sample array 358 * into the PWM bitmap for each LED. 359 */ 360 for (i = 0; i < SAMPLE_COUNT; i++) 361 buf[i] = rackmeter_calc_sample(rm, i); 362 363 364 return IRQ_HANDLED; 365 } 366 367 static int rackmeter_probe(struct macio_dev* mdev, 368 const struct of_device_id *match) 369 { 370 struct device_node *i2s = NULL, *np = NULL; 371 struct rackmeter *rm = NULL; 372 struct resource ri2s, rdma; 373 int rc = -ENODEV; 374 375 pr_debug("rackmeter_probe()\n"); 376 377 /* Get i2s-a node */ 378 for_each_child_of_node(mdev->ofdev.dev.of_node, i2s) 379 if (of_node_name_eq(i2s, "i2s-a")) 380 break; 381 382 if (i2s == NULL) { 383 pr_debug(" i2s-a child not found\n"); 384 goto bail; 385 } 386 /* Get lightshow or virtual sound */ 387 for_each_child_of_node(i2s, np) { 388 if (of_node_name_eq(np, "lightshow")) 389 break; 390 if (of_node_name_eq(np, "sound") && 391 of_get_property(np, "virtual", NULL) != NULL) 392 break; 393 } 394 if (np == NULL) { 395 pr_debug(" lightshow or sound+virtual child not found\n"); 396 goto bail; 397 } 398 399 /* Create and initialize our instance data */ 400 rm = kzalloc(sizeof(*rm), GFP_KERNEL); 401 if (rm == NULL) { 402 printk(KERN_ERR "rackmeter: failed to allocate memory !\n"); 403 rc = -ENOMEM; 404 goto bail_release; 405 } 406 rm->mdev = mdev; 407 rm->i2s = i2s; 408 mutex_init(&rm->sem); 409 dev_set_drvdata(&mdev->ofdev.dev, rm); 410 /* Check resources availability. We need at least resource 0 and 1 */ 411 #if 0 /* Use that when i2s-a is finally an mdev per-se */ 412 if (macio_resource_count(mdev) < 2 || macio_irq_count(mdev) < 2) { 413 printk(KERN_ERR 414 "rackmeter: found match but lacks resources: %pOF" 415 " (%d resources, %d interrupts)\n", 416 mdev->ofdev.dev.of_node); 417 rc = -ENXIO; 418 goto bail_free; 419 } 420 if (macio_request_resources(mdev, "rackmeter")) { 421 printk(KERN_ERR 422 "rackmeter: failed to request resources: %pOF\n", 423 mdev->ofdev.dev.of_node); 424 rc = -EBUSY; 425 goto bail_free; 426 } 427 rm->irq = macio_irq(mdev, 1); 428 #else 429 rm->irq = irq_of_parse_and_map(i2s, 1); 430 if (!rm->irq || 431 of_address_to_resource(i2s, 0, &ri2s) || 432 of_address_to_resource(i2s, 1, &rdma)) { 433 printk(KERN_ERR 434 "rackmeter: found match but lacks resources: %pOF", 435 mdev->ofdev.dev.of_node); 436 rc = -ENXIO; 437 goto bail_free; 438 } 439 #endif 440 441 pr_debug(" i2s @0x%08x\n", (unsigned int)ri2s.start); 442 pr_debug(" dma @0x%08x\n", (unsigned int)rdma.start); 443 pr_debug(" irq %d\n", rm->irq); 444 445 rm->ubuf = (u8 *)__get_free_page(GFP_KERNEL); 446 if (rm->ubuf == NULL) { 447 printk(KERN_ERR 448 "rackmeter: failed to allocate samples page !\n"); 449 rc = -ENOMEM; 450 goto bail_release; 451 } 452 453 rm->dma_buf_v = dma_alloc_coherent(&macio_get_pci_dev(mdev)->dev, 454 sizeof(struct rackmeter_dma), 455 &rm->dma_buf_p, GFP_KERNEL); 456 if (rm->dma_buf_v == NULL) { 457 printk(KERN_ERR 458 "rackmeter: failed to allocate dma buffer !\n"); 459 rc = -ENOMEM; 460 goto bail_free_samples; 461 } 462 #if 0 463 rm->i2s_regs = ioremap(macio_resource_start(mdev, 0), 0x1000); 464 #else 465 rm->i2s_regs = ioremap(ri2s.start, 0x1000); 466 #endif 467 if (rm->i2s_regs == NULL) { 468 printk(KERN_ERR 469 "rackmeter: failed to map i2s registers !\n"); 470 rc = -ENXIO; 471 goto bail_free_dma; 472 } 473 #if 0 474 rm->dma_regs = ioremap(macio_resource_start(mdev, 1), 0x100); 475 #else 476 rm->dma_regs = ioremap(rdma.start, 0x100); 477 #endif 478 if (rm->dma_regs == NULL) { 479 printk(KERN_ERR 480 "rackmeter: failed to map dma registers !\n"); 481 rc = -ENXIO; 482 goto bail_unmap_i2s; 483 } 484 485 rc = rackmeter_setup(rm); 486 if (rc) { 487 printk(KERN_ERR 488 "rackmeter: failed to initialize !\n"); 489 rc = -ENXIO; 490 goto bail_unmap_dma; 491 } 492 493 rc = request_irq(rm->irq, rackmeter_irq, 0, "rackmeter", rm); 494 if (rc != 0) { 495 printk(KERN_ERR 496 "rackmeter: failed to request interrupt !\n"); 497 goto bail_stop_dma; 498 } 499 of_node_put(np); 500 return 0; 501 502 bail_stop_dma: 503 DBDMA_DO_RESET(rm->dma_regs); 504 bail_unmap_dma: 505 iounmap(rm->dma_regs); 506 bail_unmap_i2s: 507 iounmap(rm->i2s_regs); 508 bail_free_dma: 509 dma_free_coherent(&macio_get_pci_dev(mdev)->dev, 510 sizeof(struct rackmeter_dma), 511 rm->dma_buf_v, rm->dma_buf_p); 512 bail_free_samples: 513 free_page((unsigned long)rm->ubuf); 514 bail_release: 515 #if 0 516 macio_release_resources(mdev); 517 #endif 518 bail_free: 519 kfree(rm); 520 bail: 521 of_node_put(i2s); 522 of_node_put(np); 523 dev_set_drvdata(&mdev->ofdev.dev, NULL); 524 return rc; 525 } 526 527 static int rackmeter_remove(struct macio_dev* mdev) 528 { 529 struct rackmeter *rm = dev_get_drvdata(&mdev->ofdev.dev); 530 531 /* Stop CPU sniffer timer & work queues */ 532 rackmeter_stop_cpu_sniffer(rm); 533 534 /* Clear reference to private data */ 535 dev_set_drvdata(&mdev->ofdev.dev, NULL); 536 537 /* Stop/reset dbdma */ 538 DBDMA_DO_RESET(rm->dma_regs); 539 540 /* Release the IRQ */ 541 free_irq(rm->irq, rm); 542 543 /* Unmap registers */ 544 iounmap(rm->dma_regs); 545 iounmap(rm->i2s_regs); 546 547 /* Free DMA */ 548 dma_free_coherent(&macio_get_pci_dev(mdev)->dev, 549 sizeof(struct rackmeter_dma), 550 rm->dma_buf_v, rm->dma_buf_p); 551 552 /* Free samples */ 553 free_page((unsigned long)rm->ubuf); 554 555 #if 0 556 /* Release resources */ 557 macio_release_resources(mdev); 558 #endif 559 560 /* Get rid of me */ 561 kfree(rm); 562 563 return 0; 564 } 565 566 static int rackmeter_shutdown(struct macio_dev* mdev) 567 { 568 struct rackmeter *rm = dev_get_drvdata(&mdev->ofdev.dev); 569 570 if (rm == NULL) 571 return -ENODEV; 572 573 /* Stop CPU sniffer timer & work queues */ 574 rackmeter_stop_cpu_sniffer(rm); 575 576 /* Stop/reset dbdma */ 577 DBDMA_DO_RESET(rm->dma_regs); 578 579 return 0; 580 } 581 582 static const struct of_device_id rackmeter_match[] = { 583 { .name = "i2s" }, 584 { } 585 }; 586 MODULE_DEVICE_TABLE(of, rackmeter_match); 587 588 static struct macio_driver rackmeter_driver = { 589 .driver = { 590 .name = "rackmeter", 591 .owner = THIS_MODULE, 592 .of_match_table = rackmeter_match, 593 }, 594 .probe = rackmeter_probe, 595 .remove = rackmeter_remove, 596 .shutdown = rackmeter_shutdown, 597 }; 598 599 600 static int __init rackmeter_init(void) 601 { 602 pr_debug("rackmeter_init()\n"); 603 604 return macio_register_driver(&rackmeter_driver); 605 } 606 607 static void __exit rackmeter_exit(void) 608 { 609 pr_debug("rackmeter_exit()\n"); 610 611 macio_unregister_driver(&rackmeter_driver); 612 } 613 614 module_init(rackmeter_init); 615 module_exit(rackmeter_exit); 616 617 618 MODULE_LICENSE("GPL"); 619 MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>"); 620 MODULE_DESCRIPTION("RackMeter: Support vu-meter on XServe front panel"); 621