1 /* 2 * RackMac vu-meter driver 3 * 4 * (c) Copyright 2006 Benjamin Herrenschmidt, IBM Corp. 5 * <benh@kernel.crashing.org> 6 * 7 * Released under the term of the GNU GPL v2. 8 * 9 * Support the CPU-meter LEDs of the Xserve G5 10 * 11 * TODO: Implement PWM to do variable intensity and provide userland 12 * interface for fun. Also, the CPU-meter could be made nicer by being 13 * a bit less "immediate" but giving instead a more average load over 14 * time. Patches welcome :-) 15 * 16 */ 17 #undef DEBUG 18 19 #include <linux/types.h> 20 #include <linux/kernel.h> 21 #include <linux/slab.h> 22 #include <linux/device.h> 23 #include <linux/interrupt.h> 24 #include <linux/module.h> 25 #include <linux/pci.h> 26 #include <linux/dma-mapping.h> 27 #include <linux/kernel_stat.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 cputime64_t prev_wall; 54 cputime64_t 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 cputime64_t get_cpu_idle_time(unsigned int cpu) 83 { 84 u64 retval; 85 86 retval = kcpustat_cpu(cpu).cpustat[CPUTIME_IDLE] + 87 kcpustat_cpu(cpu).cpustat[CPUTIME_IOWAIT]; 88 89 if (rackmeter_ignore_nice) 90 retval += kcpustat_cpu(cpu).cpustat[CPUTIME_NICE]; 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, SAMPLE_COUNT & sizeof(u32)); 156 memset(rdma->buf2, 0, SAMPLE_COUNT & sizeof(u32)); 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 st_le16(&cmd->req_count, 4); 184 st_le16(&cmd->command, STORE_WORD | INTR_ALWAYS | KEY_SYSTEM); 185 st_le32(&cmd->phy_addr, rm->dma_buf_p + 186 offsetof(struct rackmeter_dma, mark)); 187 st_le32(&cmd->cmd_dep, 0x02000000); 188 cmd++; 189 190 st_le16(&cmd->req_count, SAMPLE_COUNT * 4); 191 st_le16(&cmd->command, OUTPUT_MORE); 192 st_le32(&cmd->phy_addr, rm->dma_buf_p + 193 offsetof(struct rackmeter_dma, buf1)); 194 cmd++; 195 196 st_le16(&cmd->req_count, 4); 197 st_le16(&cmd->command, STORE_WORD | INTR_ALWAYS | KEY_SYSTEM); 198 st_le32(&cmd->phy_addr, rm->dma_buf_p + 199 offsetof(struct rackmeter_dma, mark)); 200 st_le32(&cmd->cmd_dep, 0x01000000); 201 cmd++; 202 203 st_le16(&cmd->req_count, SAMPLE_COUNT * 4); 204 st_le16(&cmd->command, OUTPUT_MORE | BR_ALWAYS); 205 st_le32(&cmd->phy_addr, rm->dma_buf_p + 206 offsetof(struct rackmeter_dma, buf2)); 207 st_le32(&cmd->cmd_dep, 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 cputime64_t cur_jiffies, total_idle_ticks; 219 unsigned int total_ticks, idle_ticks; 220 int i, offset, load, cumm, pause; 221 222 cur_jiffies = jiffies64_to_cputime64(get_jiffies_64()); 223 total_ticks = (unsigned int) (cur_jiffies - rcpu->prev_wall); 224 rcpu->prev_wall = cur_jiffies; 225 226 total_idle_ticks = get_cpu_idle_time(cpu); 227 idle_ticks = (unsigned int) (total_idle_ticks - rcpu->prev_idle); 228 rcpu->prev_idle = total_idle_ticks; 229 230 /* We do a very dumb calculation to update the LEDs for now, 231 * we'll do better once we have actual PWM implemented 232 */ 233 load = (9 * (total_ticks - idle_ticks)) / total_ticks; 234 235 offset = cpu << 3; 236 cumm = 0; 237 for (i = 0; i < 8; i++) { 238 u8 ub = (load > i) ? 0xff : 0; 239 rm->ubuf[i + offset] = ub; 240 cumm |= ub; 241 } 242 rcpu->zero = (cumm == 0); 243 244 /* Now check if LEDs are all 0, we can stop DMA */ 245 pause = (rm->cpu[0].zero && rm->cpu[1].zero); 246 if (pause != rm->paused) { 247 mutex_lock(&rm->sem); 248 pause = (rm->cpu[0].zero && rm->cpu[1].zero); 249 rackmeter_do_pause(rm, pause); 250 mutex_unlock(&rm->sem); 251 } 252 schedule_delayed_work_on(cpu, &rcpu->sniffer, 253 msecs_to_jiffies(CPU_SAMPLING_RATE)); 254 } 255 256 static void rackmeter_init_cpu_sniffer(struct rackmeter *rm) 257 { 258 unsigned int cpu; 259 260 /* This driver works only with 1 or 2 CPUs numbered 0 and 1, 261 * but that's really all we have on Apple Xserve. It doesn't 262 * play very nice with CPU hotplug neither but we don't do that 263 * on those machines yet 264 */ 265 266 rm->cpu[0].rm = rm; 267 INIT_DELAYED_WORK(&rm->cpu[0].sniffer, rackmeter_do_timer); 268 rm->cpu[1].rm = rm; 269 INIT_DELAYED_WORK(&rm->cpu[1].sniffer, rackmeter_do_timer); 270 271 for_each_online_cpu(cpu) { 272 struct rackmeter_cpu *rcpu; 273 274 if (cpu > 1) 275 continue; 276 rcpu = &rm->cpu[cpu]; 277 rcpu->prev_idle = get_cpu_idle_time(cpu); 278 rcpu->prev_wall = jiffies64_to_cputime64(get_jiffies_64()); 279 schedule_delayed_work_on(cpu, &rm->cpu[cpu].sniffer, 280 msecs_to_jiffies(CPU_SAMPLING_RATE)); 281 } 282 } 283 284 static void rackmeter_stop_cpu_sniffer(struct rackmeter *rm) 285 { 286 cancel_delayed_work_sync(&rm->cpu[0].sniffer); 287 cancel_delayed_work_sync(&rm->cpu[1].sniffer); 288 } 289 290 static int rackmeter_setup(struct rackmeter *rm) 291 { 292 pr_debug("rackmeter: setting up i2s..\n"); 293 rackmeter_setup_i2s(rm); 294 295 pr_debug("rackmeter: setting up default pattern..\n"); 296 rackmeter_set_default_pattern(rm); 297 298 pr_debug("rackmeter: setting up dbdma..\n"); 299 rackmeter_setup_dbdma(rm); 300 301 pr_debug("rackmeter: start CPU measurements..\n"); 302 rackmeter_init_cpu_sniffer(rm); 303 304 printk(KERN_INFO "RackMeter initialized\n"); 305 306 return 0; 307 } 308 309 /* XXX FIXME: No PWM yet, this is 0/1 */ 310 static u32 rackmeter_calc_sample(struct rackmeter *rm, unsigned int index) 311 { 312 int led; 313 u32 sample = 0; 314 315 for (led = 0; led < 16; led++) { 316 sample >>= 1; 317 sample |= ((rm->ubuf[led] >= 0x80) << 15); 318 } 319 return (sample << 17) | (sample >> 15); 320 } 321 322 static irqreturn_t rackmeter_irq(int irq, void *arg) 323 { 324 struct rackmeter *rm = arg; 325 struct rackmeter_dma *db = rm->dma_buf_v; 326 unsigned int mark, i; 327 u32 *buf; 328 329 /* Flush PCI buffers with an MMIO read. Maybe we could actually 330 * check the status one day ... in case things go wrong, though 331 * this never happened to me 332 */ 333 (void)in_le32(&rm->dma_regs->status); 334 335 /* Make sure the CPU gets us in order */ 336 rmb(); 337 338 /* Read mark */ 339 mark = db->mark; 340 if (mark != 1 && mark != 2) { 341 printk(KERN_WARNING "rackmeter: Incorrect DMA mark 0x%08x\n", 342 mark); 343 /* We allow for 3 errors like that (stale DBDMA irqs) */ 344 if (++rm->stale_irq > 3) { 345 printk(KERN_ERR "rackmeter: Too many errors," 346 " stopping DMA\n"); 347 DBDMA_DO_RESET(rm->dma_regs); 348 } 349 return IRQ_HANDLED; 350 } 351 352 /* Next buffer we need to fill is mark value */ 353 buf = mark == 1 ? db->buf1 : db->buf2; 354 355 /* Fill it now. This routine converts the 8 bits depth sample array 356 * into the PWM bitmap for each LED. 357 */ 358 for (i = 0; i < SAMPLE_COUNT; i++) 359 buf[i] = rackmeter_calc_sample(rm, i); 360 361 362 return IRQ_HANDLED; 363 } 364 365 static int rackmeter_probe(struct macio_dev* mdev, 366 const struct of_device_id *match) 367 { 368 struct device_node *i2s = NULL, *np = NULL; 369 struct rackmeter *rm = NULL; 370 struct resource ri2s, rdma; 371 int rc = -ENODEV; 372 373 pr_debug("rackmeter_probe()\n"); 374 375 /* Get i2s-a node */ 376 while ((i2s = of_get_next_child(mdev->ofdev.dev.of_node, i2s)) != NULL) 377 if (strcmp(i2s->name, "i2s-a") == 0) 378 break; 379 if (i2s == NULL) { 380 pr_debug(" i2s-a child not found\n"); 381 goto bail; 382 } 383 /* Get lightshow or virtual sound */ 384 while ((np = of_get_next_child(i2s, np)) != NULL) { 385 if (strcmp(np->name, "lightshow") == 0) 386 break; 387 if ((strcmp(np->name, "sound") == 0) && 388 of_get_property(np, "virtual", NULL) != NULL) 389 break; 390 } 391 if (np == NULL) { 392 pr_debug(" lightshow or sound+virtual child not found\n"); 393 goto bail; 394 } 395 396 /* Create and initialize our instance data */ 397 rm = kzalloc(sizeof(struct rackmeter), GFP_KERNEL); 398 if (rm == NULL) { 399 printk(KERN_ERR "rackmeter: failed to allocate memory !\n"); 400 rc = -ENOMEM; 401 goto bail_release; 402 } 403 rm->mdev = mdev; 404 rm->i2s = i2s; 405 mutex_init(&rm->sem); 406 dev_set_drvdata(&mdev->ofdev.dev, rm); 407 /* Check resources availability. We need at least resource 0 and 1 */ 408 #if 0 /* Use that when i2s-a is finally an mdev per-se */ 409 if (macio_resource_count(mdev) < 2 || macio_irq_count(mdev) < 2) { 410 printk(KERN_ERR 411 "rackmeter: found match but lacks resources: %s" 412 " (%d resources, %d interrupts)\n", 413 mdev->ofdev.node->full_name); 414 rc = -ENXIO; 415 goto bail_free; 416 } 417 if (macio_request_resources(mdev, "rackmeter")) { 418 printk(KERN_ERR 419 "rackmeter: failed to request resources: %s\n", 420 mdev->ofdev.node->full_name); 421 rc = -EBUSY; 422 goto bail_free; 423 } 424 rm->irq = macio_irq(mdev, 1); 425 #else 426 rm->irq = irq_of_parse_and_map(i2s, 1); 427 if (rm->irq == NO_IRQ || 428 of_address_to_resource(i2s, 0, &ri2s) || 429 of_address_to_resource(i2s, 1, &rdma)) { 430 printk(KERN_ERR 431 "rackmeter: found match but lacks resources: %s", 432 mdev->ofdev.dev.of_node->full_name); 433 rc = -ENXIO; 434 goto bail_free; 435 } 436 #endif 437 438 pr_debug(" i2s @0x%08x\n", (unsigned int)ri2s.start); 439 pr_debug(" dma @0x%08x\n", (unsigned int)rdma.start); 440 pr_debug(" irq %d\n", rm->irq); 441 442 rm->ubuf = (u8 *)__get_free_page(GFP_KERNEL); 443 if (rm->ubuf == NULL) { 444 printk(KERN_ERR 445 "rackmeter: failed to allocate samples page !\n"); 446 rc = -ENOMEM; 447 goto bail_release; 448 } 449 450 rm->dma_buf_v = dma_alloc_coherent(&macio_get_pci_dev(mdev)->dev, 451 sizeof(struct rackmeter_dma), 452 &rm->dma_buf_p, GFP_KERNEL); 453 if (rm->dma_buf_v == NULL) { 454 printk(KERN_ERR 455 "rackmeter: failed to allocate dma buffer !\n"); 456 rc = -ENOMEM; 457 goto bail_free_samples; 458 } 459 #if 0 460 rm->i2s_regs = ioremap(macio_resource_start(mdev, 0), 0x1000); 461 #else 462 rm->i2s_regs = ioremap(ri2s.start, 0x1000); 463 #endif 464 if (rm->i2s_regs == NULL) { 465 printk(KERN_ERR 466 "rackmeter: failed to map i2s registers !\n"); 467 rc = -ENXIO; 468 goto bail_free_dma; 469 } 470 #if 0 471 rm->dma_regs = ioremap(macio_resource_start(mdev, 1), 0x100); 472 #else 473 rm->dma_regs = ioremap(rdma.start, 0x100); 474 #endif 475 if (rm->dma_regs == NULL) { 476 printk(KERN_ERR 477 "rackmeter: failed to map dma registers !\n"); 478 rc = -ENXIO; 479 goto bail_unmap_i2s; 480 } 481 482 rc = rackmeter_setup(rm); 483 if (rc) { 484 printk(KERN_ERR 485 "rackmeter: failed to initialize !\n"); 486 rc = -ENXIO; 487 goto bail_unmap_dma; 488 } 489 490 rc = request_irq(rm->irq, rackmeter_irq, 0, "rackmeter", rm); 491 if (rc != 0) { 492 printk(KERN_ERR 493 "rackmeter: failed to request interrupt !\n"); 494 goto bail_stop_dma; 495 } 496 of_node_put(np); 497 return 0; 498 499 bail_stop_dma: 500 DBDMA_DO_RESET(rm->dma_regs); 501 bail_unmap_dma: 502 iounmap(rm->dma_regs); 503 bail_unmap_i2s: 504 iounmap(rm->i2s_regs); 505 bail_free_dma: 506 dma_free_coherent(&macio_get_pci_dev(mdev)->dev, 507 sizeof(struct rackmeter_dma), 508 rm->dma_buf_v, rm->dma_buf_p); 509 bail_free_samples: 510 free_page((unsigned long)rm->ubuf); 511 bail_release: 512 #if 0 513 macio_release_resources(mdev); 514 #endif 515 bail_free: 516 kfree(rm); 517 bail: 518 of_node_put(i2s); 519 of_node_put(np); 520 dev_set_drvdata(&mdev->ofdev.dev, NULL); 521 return rc; 522 } 523 524 static int rackmeter_remove(struct macio_dev* mdev) 525 { 526 struct rackmeter *rm = dev_get_drvdata(&mdev->ofdev.dev); 527 528 /* Stop CPU sniffer timer & work queues */ 529 rackmeter_stop_cpu_sniffer(rm); 530 531 /* Clear reference to private data */ 532 dev_set_drvdata(&mdev->ofdev.dev, NULL); 533 534 /* Stop/reset dbdma */ 535 DBDMA_DO_RESET(rm->dma_regs); 536 537 /* Release the IRQ */ 538 free_irq(rm->irq, rm); 539 540 /* Unmap registers */ 541 iounmap(rm->dma_regs); 542 iounmap(rm->i2s_regs); 543 544 /* Free DMA */ 545 dma_free_coherent(&macio_get_pci_dev(mdev)->dev, 546 sizeof(struct rackmeter_dma), 547 rm->dma_buf_v, rm->dma_buf_p); 548 549 /* Free samples */ 550 free_page((unsigned long)rm->ubuf); 551 552 #if 0 553 /* Release resources */ 554 macio_release_resources(mdev); 555 #endif 556 557 /* Get rid of me */ 558 kfree(rm); 559 560 return 0; 561 } 562 563 static int rackmeter_shutdown(struct macio_dev* mdev) 564 { 565 struct rackmeter *rm = dev_get_drvdata(&mdev->ofdev.dev); 566 567 if (rm == NULL) 568 return -ENODEV; 569 570 /* Stop CPU sniffer timer & work queues */ 571 rackmeter_stop_cpu_sniffer(rm); 572 573 /* Stop/reset dbdma */ 574 DBDMA_DO_RESET(rm->dma_regs); 575 576 return 0; 577 } 578 579 static struct of_device_id rackmeter_match[] = { 580 { .name = "i2s" }, 581 { } 582 }; 583 584 static struct macio_driver rackmeter_driver = { 585 .driver = { 586 .name = "rackmeter", 587 .owner = THIS_MODULE, 588 .of_match_table = rackmeter_match, 589 }, 590 .probe = rackmeter_probe, 591 .remove = rackmeter_remove, 592 .shutdown = rackmeter_shutdown, 593 }; 594 595 596 static int __init rackmeter_init(void) 597 { 598 pr_debug("rackmeter_init()\n"); 599 600 return macio_register_driver(&rackmeter_driver); 601 } 602 603 static void __exit rackmeter_exit(void) 604 { 605 pr_debug("rackmeter_exit()\n"); 606 607 macio_unregister_driver(&rackmeter_driver); 608 } 609 610 module_init(rackmeter_init); 611 module_exit(rackmeter_exit); 612 613 614 MODULE_LICENSE("GPL"); 615 MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>"); 616 MODULE_DESCRIPTION("RackMeter: Support vu-meter on XServe front panel"); 617