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/device.h> 22#include <linux/interrupt.h> 23#include <linux/module.h> 24#include <linux/pci.h> 25#include <linux/dma-mapping.h> 26#include <linux/kernel_stat.h> 27 28#include <asm/io.h> 29#include <asm/prom.h> 30#include <asm/machdep.h> 31#include <asm/pmac_feature.h> 32#include <asm/dbdma.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 43struct 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 50struct 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 58struct 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 */ 74static 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 */ 82static inline cputime64_t get_cpu_idle_time(unsigned int cpu) 83{ 84 cputime64_t retval; 85 86 retval = cputime64_add(kstat_cpu(cpu).cpustat.idle, 87 kstat_cpu(cpu).cpustat.iowait); 88 89 if (rackmeter_ignore_nice) 90 retval = cputime64_add(retval, kstat_cpu(cpu).cpustat.nice); 91 92 return retval; 93} 94 95static 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 132static 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 144static 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 166static 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 212static 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)cputime64_sub(cur_jiffies, 224 rcpu->prev_wall); 225 rcpu->prev_wall = cur_jiffies; 226 227 total_idle_ticks = get_cpu_idle_time(cpu); 228 idle_ticks = (unsigned int) cputime64_sub(total_idle_ticks, 229 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 258static void __devinit 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 286static void __devexit rackmeter_stop_cpu_sniffer(struct rackmeter *rm) 287{ 288 cancel_rearming_delayed_work(&rm->cpu[0].sniffer); 289 cancel_rearming_delayed_work(&rm->cpu[1].sniffer); 290} 291 292static 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 311static 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 323static 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 366static int __devinit 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 while ((i2s = of_get_next_child(mdev->ofdev.node, i2s)) != NULL) 378 if (strcmp(i2s->name, "i2s-a") == 0) 379 break; 380 if (i2s == NULL) { 381 pr_debug(" i2s-a child not found\n"); 382 goto bail; 383 } 384 /* Get lightshow or virtual sound */ 385 while ((np = of_get_next_child(i2s, np)) != NULL) { 386 if (strcmp(np->name, "lightshow") == 0) 387 break; 388 if ((strcmp(np->name, "sound") == 0) && 389 of_get_property(np, "virtual", NULL) != NULL) 390 break; 391 } 392 if (np == NULL) { 393 pr_debug(" lightshow or sound+virtual child not found\n"); 394 goto bail; 395 } 396 397 /* Create and initialize our instance data */ 398 rm = kzalloc(sizeof(struct rackmeter), GFP_KERNEL); 399 if (rm == NULL) { 400 printk(KERN_ERR "rackmeter: failed to allocate memory !\n"); 401 rc = -ENOMEM; 402 goto bail_release; 403 } 404 rm->mdev = mdev; 405 rm->i2s = i2s; 406 mutex_init(&rm->sem); 407 dev_set_drvdata(&mdev->ofdev.dev, rm); 408 /* Check resources availability. We need at least resource 0 and 1 */ 409 rm->irq = irq_of_parse_and_map(i2s, 1); 410 if (rm->irq == NO_IRQ || 411 of_address_to_resource(i2s, 0, &ri2s) || 412 of_address_to_resource(i2s, 1, &rdma)) { 413 printk(KERN_ERR 414 "rackmeter: found match but lacks resources: %s", 415 mdev->ofdev.node->full_name); 416 rc = -ENXIO; 417 goto bail_free; 418 } 419 420 pr_debug(" i2s @0x%08x\n", (unsigned int)ri2s.start); 421 pr_debug(" dma @0x%08x\n", (unsigned int)rdma.start); 422 pr_debug(" irq %d\n", rm->irq); 423 424 rm->ubuf = (u8 *)__get_free_page(GFP_KERNEL); 425 if (rm->ubuf == NULL) { 426 printk(KERN_ERR 427 "rackmeter: failed to allocate samples page !\n"); 428 rc = -ENOMEM; 429 goto bail_release; 430 } 431 432 rm->dma_buf_v = dma_alloc_coherent(&macio_get_pci_dev(mdev)->dev, 433 sizeof(struct rackmeter_dma), 434 &rm->dma_buf_p, GFP_KERNEL); 435 if (rm->dma_buf_v == NULL) { 436 printk(KERN_ERR 437 "rackmeter: failed to allocate dma buffer !\n"); 438 rc = -ENOMEM; 439 goto bail_free_samples; 440 } 441 rm->i2s_regs = ioremap(ri2s.start, 0x1000); 442 if (rm->i2s_regs == NULL) { 443 printk(KERN_ERR 444 "rackmeter: failed to map i2s registers !\n"); 445 rc = -ENXIO; 446 goto bail_free_dma; 447 } 448 rm->dma_regs = ioremap(rdma.start, 0x100); 449 if (rm->dma_regs == NULL) { 450 printk(KERN_ERR 451 "rackmeter: failed to map dma registers !\n"); 452 rc = -ENXIO; 453 goto bail_unmap_i2s; 454 } 455 456 rc = rackmeter_setup(rm); 457 if (rc) { 458 printk(KERN_ERR 459 "rackmeter: failed to initialize !\n"); 460 rc = -ENXIO; 461 goto bail_unmap_dma; 462 } 463 464 rc = request_irq(rm->irq, rackmeter_irq, 0, "rackmeter", rm); 465 if (rc != 0) { 466 printk(KERN_ERR 467 "rackmeter: failed to request interrupt !\n"); 468 goto bail_stop_dma; 469 } 470 of_node_put(np); 471 return 0; 472 473 bail_stop_dma: 474 DBDMA_DO_RESET(rm->dma_regs); 475 bail_unmap_dma: 476 iounmap(rm->dma_regs); 477 bail_unmap_i2s: 478 iounmap(rm->i2s_regs); 479 bail_free_dma: 480 dma_free_coherent(&macio_get_pci_dev(mdev)->dev, 481 sizeof(struct rackmeter_dma), 482 rm->dma_buf_v, rm->dma_buf_p); 483 bail_free_samples: 484 free_page((unsigned long)rm->ubuf); 485 bail_release: 486 bail_free: 487 kfree(rm); 488 bail: 489 of_node_put(i2s); 490 of_node_put(np); 491 dev_set_drvdata(&mdev->ofdev.dev, NULL); 492 return rc; 493} 494 495static int __devexit rackmeter_remove(struct macio_dev* mdev) 496{ 497 struct rackmeter *rm = dev_get_drvdata(&mdev->ofdev.dev); 498 499 /* Stop CPU sniffer timer & work queues */ 500 rackmeter_stop_cpu_sniffer(rm); 501 502 /* Clear reference to private data */ 503 dev_set_drvdata(&mdev->ofdev.dev, NULL); 504 505 /* Stop/reset dbdma */ 506 DBDMA_DO_RESET(rm->dma_regs); 507 508 /* Release the IRQ */ 509 free_irq(rm->irq, rm); 510 511 /* Unmap registers */ 512 iounmap(rm->dma_regs); 513 iounmap(rm->i2s_regs); 514 515 /* Free DMA */ 516 dma_free_coherent(&macio_get_pci_dev(mdev)->dev, 517 sizeof(struct rackmeter_dma), 518 rm->dma_buf_v, rm->dma_buf_p); 519 520 /* Free samples */ 521 free_page((unsigned long)rm->ubuf); 522 523 524 /* Get rid of me */ 525 kfree(rm); 526 527 return 0; 528} 529 530static int rackmeter_shutdown(struct macio_dev* mdev) 531{ 532 struct rackmeter *rm = dev_get_drvdata(&mdev->ofdev.dev); 533 534 if (rm == NULL) 535 return -ENODEV; 536 537 /* Stop CPU sniffer timer & work queues */ 538 rackmeter_stop_cpu_sniffer(rm); 539 540 /* Stop/reset dbdma */ 541 DBDMA_DO_RESET(rm->dma_regs); 542 543 return 0; 544} 545 546static struct of_device_id rackmeter_match[] = { 547 { .name = "i2s" }, 548 { } 549}; 550 551static struct macio_driver rackmeter_drv = { 552 .name = "rackmeter", 553 .owner = THIS_MODULE, 554 .match_table = rackmeter_match, 555 .probe = rackmeter_probe, 556 .remove = rackmeter_remove, 557 .shutdown = rackmeter_shutdown, 558}; 559 560 561static int __init rackmeter_init(void) 562{ 563 pr_debug("rackmeter_init()\n"); 564 565 return macio_register_driver(&rackmeter_drv); 566} 567 568static void __exit rackmeter_exit(void) 569{ 570 pr_debug("rackmeter_exit()\n"); 571 572 macio_unregister_driver(&rackmeter_drv); 573} 574 575module_init(rackmeter_init); 576module_exit(rackmeter_exit); 577 578 579MODULE_LICENSE("GPL"); 580MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>"); 581MODULE_DESCRIPTION("RackMeter: Support vu-meter on XServe front panel"); 582