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 #include <linux/of_address.h> 29 #include <linux/of_irq.h> 30 31 #include <asm/io.h> 32 #include <asm/prom.h> 33 #include <asm/machdep.h> 34 #include <asm/pmac_feature.h> 35 #include <asm/dbdma.h> 36 #include <asm/macio.h> 37 #include <asm/keylargo.h> 38 39 /* Number of samples in a sample buffer */ 40 #define SAMPLE_COUNT 256 41 42 /* CPU meter sampling rate in ms */ 43 #define CPU_SAMPLING_RATE 250 44 45 struct rackmeter_dma { 46 struct dbdma_cmd cmd[4] ____cacheline_aligned; 47 u32 mark ____cacheline_aligned; 48 u32 buf1[SAMPLE_COUNT] ____cacheline_aligned; 49 u32 buf2[SAMPLE_COUNT] ____cacheline_aligned; 50 } ____cacheline_aligned; 51 52 struct rackmeter_cpu { 53 struct delayed_work sniffer; 54 struct rackmeter *rm; 55 cputime64_t prev_wall; 56 cputime64_t prev_idle; 57 int zero; 58 } ____cacheline_aligned; 59 60 struct rackmeter { 61 struct macio_dev *mdev; 62 unsigned int irq; 63 struct device_node *i2s; 64 u8 *ubuf; 65 struct dbdma_regs __iomem *dma_regs; 66 void __iomem *i2s_regs; 67 dma_addr_t dma_buf_p; 68 struct rackmeter_dma *dma_buf_v; 69 int stale_irq; 70 struct rackmeter_cpu cpu[2]; 71 int paused; 72 struct mutex sem; 73 }; 74 75 /* To be set as a tunable */ 76 static int rackmeter_ignore_nice; 77 78 /* This GPIO is whacked by the OS X driver when initializing */ 79 #define RACKMETER_MAGIC_GPIO 0x78 80 81 /* This is copied from cpufreq_ondemand, maybe we should put it in 82 * a common header somewhere 83 */ 84 static inline cputime64_t get_cpu_idle_time(unsigned int cpu) 85 { 86 u64 retval; 87 88 retval = kcpustat_cpu(cpu).cpustat[CPUTIME_IDLE] + 89 kcpustat_cpu(cpu).cpustat[CPUTIME_IOWAIT]; 90 91 if (rackmeter_ignore_nice) 92 retval += kcpustat_cpu(cpu).cpustat[CPUTIME_NICE]; 93 94 return retval; 95 } 96 97 static void rackmeter_setup_i2s(struct rackmeter *rm) 98 { 99 struct macio_chip *macio = rm->mdev->bus->chip; 100 101 /* First whack magic GPIO */ 102 pmac_call_feature(PMAC_FTR_WRITE_GPIO, NULL, RACKMETER_MAGIC_GPIO, 5); 103 104 105 /* Call feature code to enable the sound channel and the proper 106 * clock sources 107 */ 108 pmac_call_feature(PMAC_FTR_SOUND_CHIP_ENABLE, rm->i2s, 0, 1); 109 110 /* Power i2s and stop i2s clock. We whack MacIO FCRs directly for now. 111 * This is a bit racy, thus we should add new platform functions to 112 * handle that. snd-aoa needs that too 113 */ 114 MACIO_BIS(KEYLARGO_FCR1, KL1_I2S0_ENABLE); 115 MACIO_BIC(KEYLARGO_FCR1, KL1_I2S0_CLK_ENABLE_BIT); 116 (void)MACIO_IN32(KEYLARGO_FCR1); 117 udelay(10); 118 119 /* Then setup i2s. For now, we use the same magic value that 120 * the OS X driver seems to use. We might want to play around 121 * with the clock divisors later 122 */ 123 out_le32(rm->i2s_regs + 0x10, 0x01fa0000); 124 (void)in_le32(rm->i2s_regs + 0x10); 125 udelay(10); 126 127 /* Fully restart i2s*/ 128 MACIO_BIS(KEYLARGO_FCR1, KL1_I2S0_CELL_ENABLE | 129 KL1_I2S0_CLK_ENABLE_BIT); 130 (void)MACIO_IN32(KEYLARGO_FCR1); 131 udelay(10); 132 } 133 134 static void rackmeter_set_default_pattern(struct rackmeter *rm) 135 { 136 int i; 137 138 for (i = 0; i < 16; i++) { 139 if (i < 8) 140 rm->ubuf[i] = (i & 1) * 255; 141 else 142 rm->ubuf[i] = ((~i) & 1) * 255; 143 } 144 } 145 146 static void rackmeter_do_pause(struct rackmeter *rm, int pause) 147 { 148 struct rackmeter_dma *rdma = rm->dma_buf_v; 149 150 pr_debug("rackmeter: %s\n", pause ? "paused" : "started"); 151 152 rm->paused = pause; 153 if (pause) { 154 DBDMA_DO_STOP(rm->dma_regs); 155 return; 156 } 157 memset(rdma->buf1, 0, ARRAY_SIZE(rdma->buf1)); 158 memset(rdma->buf2, 0, ARRAY_SIZE(rdma->buf2)); 159 160 rm->dma_buf_v->mark = 0; 161 162 mb(); 163 out_le32(&rm->dma_regs->cmdptr_hi, 0); 164 out_le32(&rm->dma_regs->cmdptr, rm->dma_buf_p); 165 out_le32(&rm->dma_regs->control, (RUN << 16) | RUN); 166 } 167 168 static void rackmeter_setup_dbdma(struct rackmeter *rm) 169 { 170 struct rackmeter_dma *db = rm->dma_buf_v; 171 struct dbdma_cmd *cmd = db->cmd; 172 173 /* Make sure dbdma is reset */ 174 DBDMA_DO_RESET(rm->dma_regs); 175 176 pr_debug("rackmeter: mark offset=0x%zx\n", 177 offsetof(struct rackmeter_dma, mark)); 178 pr_debug("rackmeter: buf1 offset=0x%zx\n", 179 offsetof(struct rackmeter_dma, buf1)); 180 pr_debug("rackmeter: buf2 offset=0x%zx\n", 181 offsetof(struct rackmeter_dma, buf2)); 182 183 /* Prepare 4 dbdma commands for the 2 buffers */ 184 memset(cmd, 0, 4 * sizeof(struct dbdma_cmd)); 185 cmd->req_count = cpu_to_le16(4); 186 cmd->command = cpu_to_le16(STORE_WORD | INTR_ALWAYS | KEY_SYSTEM); 187 cmd->phy_addr = cpu_to_le32(rm->dma_buf_p + 188 offsetof(struct rackmeter_dma, mark)); 189 cmd->cmd_dep = cpu_to_le32(0x02000000); 190 cmd++; 191 192 cmd->req_count = cpu_to_le16(SAMPLE_COUNT * 4); 193 cmd->command = cpu_to_le16(OUTPUT_MORE); 194 cmd->phy_addr = cpu_to_le32(rm->dma_buf_p + 195 offsetof(struct rackmeter_dma, buf1)); 196 cmd++; 197 198 cmd->req_count = cpu_to_le16(4); 199 cmd->command = cpu_to_le16(STORE_WORD | INTR_ALWAYS | KEY_SYSTEM); 200 cmd->phy_addr = cpu_to_le32(rm->dma_buf_p + 201 offsetof(struct rackmeter_dma, mark)); 202 cmd->cmd_dep = cpu_to_le32(0x01000000); 203 cmd++; 204 205 cmd->req_count = cpu_to_le16(SAMPLE_COUNT * 4); 206 cmd->command = cpu_to_le16(OUTPUT_MORE | BR_ALWAYS); 207 cmd->phy_addr = cpu_to_le32(rm->dma_buf_p + 208 offsetof(struct rackmeter_dma, buf2)); 209 cmd->cmd_dep = cpu_to_le32(rm->dma_buf_p); 210 211 rackmeter_do_pause(rm, 0); 212 } 213 214 static void rackmeter_do_timer(struct work_struct *work) 215 { 216 struct rackmeter_cpu *rcpu = 217 container_of(work, struct rackmeter_cpu, sniffer.work); 218 struct rackmeter *rm = rcpu->rm; 219 unsigned int cpu = smp_processor_id(); 220 cputime64_t cur_jiffies, total_idle_ticks; 221 unsigned int total_ticks, idle_ticks; 222 int i, offset, load, cumm, pause; 223 224 cur_jiffies = jiffies64_to_cputime64(get_jiffies_64()); 225 total_ticks = (unsigned int) (cur_jiffies - rcpu->prev_wall); 226 rcpu->prev_wall = cur_jiffies; 227 228 total_idle_ticks = get_cpu_idle_time(cpu); 229 idle_ticks = (unsigned int) (total_idle_ticks - rcpu->prev_idle); 230 idle_ticks = min(idle_ticks, total_ticks); 231 rcpu->prev_idle = total_idle_ticks; 232 233 /* We do a very dumb calculation to update the LEDs for now, 234 * we'll do better once we have actual PWM implemented 235 */ 236 load = (9 * (total_ticks - idle_ticks)) / total_ticks; 237 238 offset = cpu << 3; 239 cumm = 0; 240 for (i = 0; i < 8; i++) { 241 u8 ub = (load > i) ? 0xff : 0; 242 rm->ubuf[i + offset] = ub; 243 cumm |= ub; 244 } 245 rcpu->zero = (cumm == 0); 246 247 /* Now check if LEDs are all 0, we can stop DMA */ 248 pause = (rm->cpu[0].zero && rm->cpu[1].zero); 249 if (pause != rm->paused) { 250 mutex_lock(&rm->sem); 251 pause = (rm->cpu[0].zero && rm->cpu[1].zero); 252 rackmeter_do_pause(rm, pause); 253 mutex_unlock(&rm->sem); 254 } 255 schedule_delayed_work_on(cpu, &rcpu->sniffer, 256 msecs_to_jiffies(CPU_SAMPLING_RATE)); 257 } 258 259 static void rackmeter_init_cpu_sniffer(struct rackmeter *rm) 260 { 261 unsigned int cpu; 262 263 /* This driver works only with 1 or 2 CPUs numbered 0 and 1, 264 * but that's really all we have on Apple Xserve. It doesn't 265 * play very nice with CPU hotplug neither but we don't do that 266 * on those machines yet 267 */ 268 269 rm->cpu[0].rm = rm; 270 INIT_DELAYED_WORK(&rm->cpu[0].sniffer, rackmeter_do_timer); 271 rm->cpu[1].rm = rm; 272 INIT_DELAYED_WORK(&rm->cpu[1].sniffer, rackmeter_do_timer); 273 274 for_each_online_cpu(cpu) { 275 struct rackmeter_cpu *rcpu; 276 277 if (cpu > 1) 278 continue; 279 rcpu = &rm->cpu[cpu]; 280 rcpu->prev_idle = get_cpu_idle_time(cpu); 281 rcpu->prev_wall = jiffies64_to_cputime64(get_jiffies_64()); 282 schedule_delayed_work_on(cpu, &rm->cpu[cpu].sniffer, 283 msecs_to_jiffies(CPU_SAMPLING_RATE)); 284 } 285 } 286 287 static void rackmeter_stop_cpu_sniffer(struct rackmeter *rm) 288 { 289 cancel_delayed_work_sync(&rm->cpu[0].sniffer); 290 cancel_delayed_work_sync(&rm->cpu[1].sniffer); 291 } 292 293 static int rackmeter_setup(struct rackmeter *rm) 294 { 295 pr_debug("rackmeter: setting up i2s..\n"); 296 rackmeter_setup_i2s(rm); 297 298 pr_debug("rackmeter: setting up default pattern..\n"); 299 rackmeter_set_default_pattern(rm); 300 301 pr_debug("rackmeter: setting up dbdma..\n"); 302 rackmeter_setup_dbdma(rm); 303 304 pr_debug("rackmeter: start CPU measurements..\n"); 305 rackmeter_init_cpu_sniffer(rm); 306 307 printk(KERN_INFO "RackMeter initialized\n"); 308 309 return 0; 310 } 311 312 /* XXX FIXME: No PWM yet, this is 0/1 */ 313 static u32 rackmeter_calc_sample(struct rackmeter *rm, unsigned int index) 314 { 315 int led; 316 u32 sample = 0; 317 318 for (led = 0; led < 16; led++) { 319 sample >>= 1; 320 sample |= ((rm->ubuf[led] >= 0x80) << 15); 321 } 322 return (sample << 17) | (sample >> 15); 323 } 324 325 static irqreturn_t rackmeter_irq(int irq, void *arg) 326 { 327 struct rackmeter *rm = arg; 328 struct rackmeter_dma *db = rm->dma_buf_v; 329 unsigned int mark, i; 330 u32 *buf; 331 332 /* Flush PCI buffers with an MMIO read. Maybe we could actually 333 * check the status one day ... in case things go wrong, though 334 * this never happened to me 335 */ 336 (void)in_le32(&rm->dma_regs->status); 337 338 /* Make sure the CPU gets us in order */ 339 rmb(); 340 341 /* Read mark */ 342 mark = db->mark; 343 if (mark != 1 && mark != 2) { 344 printk(KERN_WARNING "rackmeter: Incorrect DMA mark 0x%08x\n", 345 mark); 346 /* We allow for 3 errors like that (stale DBDMA irqs) */ 347 if (++rm->stale_irq > 3) { 348 printk(KERN_ERR "rackmeter: Too many errors," 349 " stopping DMA\n"); 350 DBDMA_DO_RESET(rm->dma_regs); 351 } 352 return IRQ_HANDLED; 353 } 354 355 /* Next buffer we need to fill is mark value */ 356 buf = mark == 1 ? db->buf1 : db->buf2; 357 358 /* Fill it now. This routine converts the 8 bits depth sample array 359 * into the PWM bitmap for each LED. 360 */ 361 for (i = 0; i < SAMPLE_COUNT; i++) 362 buf[i] = rackmeter_calc_sample(rm, i); 363 364 365 return IRQ_HANDLED; 366 } 367 368 static int rackmeter_probe(struct macio_dev* mdev, 369 const struct of_device_id *match) 370 { 371 struct device_node *i2s = NULL, *np = NULL; 372 struct rackmeter *rm = NULL; 373 struct resource ri2s, rdma; 374 int rc = -ENODEV; 375 376 pr_debug("rackmeter_probe()\n"); 377 378 /* Get i2s-a node */ 379 while ((i2s = of_get_next_child(mdev->ofdev.dev.of_node, i2s)) != NULL) 380 if (strcmp(i2s->name, "i2s-a") == 0) 381 break; 382 if (i2s == NULL) { 383 pr_debug(" i2s-a child not found\n"); 384 goto bail; 385 } 386 /* Get lightshow or virtual sound */ 387 while ((np = of_get_next_child(i2s, np)) != NULL) { 388 if (strcmp(np->name, "lightshow") == 0) 389 break; 390 if ((strcmp(np->name, "sound") == 0) && 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(struct rackmeter), 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: %s" 415 " (%d resources, %d interrupts)\n", 416 mdev->ofdev.node->full_name); 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: %s\n", 423 mdev->ofdev.node->full_name); 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 == NO_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: %s", 435 mdev->ofdev.dev.of_node->full_name); 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 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