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, SAMPLE_COUNT & sizeof(u32)); 158 memset(rdma->buf2, 0, SAMPLE_COUNT & sizeof(u32)); 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 rcpu->prev_idle = total_idle_ticks; 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 = (9 * (total_ticks - idle_ticks)) / total_ticks; 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_cputime64(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 while ((i2s = of_get_next_child(mdev->ofdev.dev.of_node, i2s)) != NULL) 379 if (strcmp(i2s->name, "i2s-a") == 0) 380 break; 381 if (i2s == NULL) { 382 pr_debug(" i2s-a child not found\n"); 383 goto bail; 384 } 385 /* Get lightshow or virtual sound */ 386 while ((np = of_get_next_child(i2s, np)) != NULL) { 387 if (strcmp(np->name, "lightshow") == 0) 388 break; 389 if ((strcmp(np->name, "sound") == 0) && 390 of_get_property(np, "virtual", NULL) != NULL) 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(struct rackmeter), 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: %s" 414 " (%d resources, %d interrupts)\n", 415 mdev->ofdev.node->full_name); 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: %s\n", 422 mdev->ofdev.node->full_name); 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 == NO_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: %s", 434 mdev->ofdev.dev.of_node->full_name); 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 struct of_device_id rackmeter_match[] = { 582 { .name = "i2s" }, 583 { } 584 }; 585 586 static struct macio_driver rackmeter_driver = { 587 .driver = { 588 .name = "rackmeter", 589 .owner = THIS_MODULE, 590 .of_match_table = rackmeter_match, 591 }, 592 .probe = rackmeter_probe, 593 .remove = rackmeter_remove, 594 .shutdown = rackmeter_shutdown, 595 }; 596 597 598 static int __init rackmeter_init(void) 599 { 600 pr_debug("rackmeter_init()\n"); 601 602 return macio_register_driver(&rackmeter_driver); 603 } 604 605 static void __exit rackmeter_exit(void) 606 { 607 pr_debug("rackmeter_exit()\n"); 608 609 macio_unregister_driver(&rackmeter_driver); 610 } 611 612 module_init(rackmeter_init); 613 module_exit(rackmeter_exit); 614 615 616 MODULE_LICENSE("GPL"); 617 MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>"); 618 MODULE_DESCRIPTION("RackMeter: Support vu-meter on XServe front panel"); 619