drivers/macintosh/rack-meter.c

   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/macio.h>
  34 #include <asm/keylargo.h>
  35
  36 /* Number of samples in a sample buffer */
  37 #define SAMPLE_COUNT            256
  38
  39 /* CPU meter sampling rate in ms */
  40 #define CPU_SAMPLING_RATE       250
  41
  42 struct rackmeter_dma {
  43         struct dbdma_cmd        cmd[4]                  ____cacheline_aligned;
  44         u32                     mark                    ____cacheline_aligned;
  45         u32                     buf1[SAMPLE_COUNT]      ____cacheline_aligned;
  46         u32                     buf2[SAMPLE_COUNT]      ____cacheline_aligned;
  47 } ____cacheline_aligned;
  48
  49 struct rackmeter_cpu {
  50         struct delayed_work     sniffer;
  51         struct rackmeter        *rm;
  52         cputime64_t             prev_wall;
  53         cputime64_t             prev_idle;
  54         int                     zero;
  55 } ____cacheline_aligned;
  56
  57 struct rackmeter {
  58         struct macio_dev                *mdev;
  59         unsigned int                    irq;
  60         struct device_node              *i2s;
  61         u8                              *ubuf;
  62         struct dbdma_regs __iomem       *dma_regs;
  63         void __iomem                    *i2s_regs;
  64         dma_addr_t                      dma_buf_p;
  65         struct rackmeter_dma            *dma_buf_v;
  66         int                             stale_irq;
  67         struct rackmeter_cpu            cpu[2];
  68         int                             paused;
  69         struct mutex                    sem;
  70 };
  71
  72 /* To be set as a tunable */
  73 static int rackmeter_ignore_nice;
  74
  75 /* This GPIO is whacked by the OS X driver when initializing */
  76 #define RACKMETER_MAGIC_GPIO    0x78
  77
  78 /* This is copied from cpufreq_ondemand, maybe we should put it in
  79  * a common header somewhere
  80  */
  81 static inline cputime64_t get_cpu_idle_time(unsigned int cpu)
  82 {
  83         cputime64_t retval;
  84
  85         retval = cputime64_add(kstat_cpu(cpu).cpustat.idle,
  86                         kstat_cpu(cpu).cpustat.iowait);
  87
  88         if (rackmeter_ignore_nice)
  89                 retval = cputime64_add(retval, kstat_cpu(cpu).cpustat.nice);
  90
  91         return retval;
  92 }
  93
  94 static void rackmeter_setup_i2s(struct rackmeter *rm)
  95 {
  96         struct macio_chip *macio = rm->mdev->bus->chip;
  97
  98         /* First whack magic GPIO */
  99         pmac_call_feature(PMAC_FTR_WRITE_GPIO, NULL, RACKMETER_MAGIC_GPIO, 5);
 100
 101
 102         /* Call feature code to enable the sound channel and the proper
 103          * clock sources
 104          */
 105         pmac_call_feature(PMAC_FTR_SOUND_CHIP_ENABLE, rm->i2s, 0, 1);
 106
 107         /* Power i2s and stop i2s clock. We whack MacIO FCRs directly for now.
 108          * This is a bit racy, thus we should add new platform functions to
 109          * handle that. snd-aoa needs that too
 110          */
 111         MACIO_BIS(KEYLARGO_FCR1, KL1_I2S0_ENABLE);
 112         MACIO_BIC(KEYLARGO_FCR1, KL1_I2S0_CLK_ENABLE_BIT);
 113         (void)MACIO_IN32(KEYLARGO_FCR1);
 114         udelay(10);
 115
 116         /* Then setup i2s. For now, we use the same magic value that
 117          * the OS X driver seems to use. We might want to play around
 118          * with the clock divisors later
 119          */
 120         out_le32(rm->i2s_regs + 0x10, 0x01fa0000);
 121         (void)in_le32(rm->i2s_regs + 0x10);
 122         udelay(10);
 123
 124         /* Fully restart i2s*/
 125         MACIO_BIS(KEYLARGO_FCR1, KL1_I2S0_CELL_ENABLE |
 126                   KL1_I2S0_CLK_ENABLE_BIT);
 127         (void)MACIO_IN32(KEYLARGO_FCR1);
 128         udelay(10);
 129 }
 130
 131 static void rackmeter_set_default_pattern(struct rackmeter *rm)
 132 {
 133         int i;
 134
 135         for (i = 0; i < 16; i++) {
 136                 if (i < 8)
 137                         rm->ubuf[i] = (i & 1) * 255;
 138                 else
 139                         rm->ubuf[i] = ((~i) & 1) * 255;
 140         }
 141 }
 142
 143 static void rackmeter_do_pause(struct rackmeter *rm, int pause)
 144 {
 145         struct rackmeter_dma *rdma = rm->dma_buf_v;
 146
 147         pr_debug("rackmeter: %s\n", pause ? "paused" : "started");
 148
 149         rm->paused = pause;
 150         if (pause) {
 151                 DBDMA_DO_STOP(rm->dma_regs);
 152                 return;
 153         }
 154         memset(rdma->buf1, 0, SAMPLE_COUNT & sizeof(u32));
 155         memset(rdma->buf2, 0, SAMPLE_COUNT & sizeof(u32));
 156
 157         rm->dma_buf_v->mark = 0;
 158
 159         mb();
 160         out_le32(&rm->dma_regs->cmdptr_hi, 0);
 161         out_le32(&rm->dma_regs->cmdptr, rm->dma_buf_p);
 162         out_le32(&rm->dma_regs->control, (RUN << 16) | RUN);
 163 }
 164
 165 static void rackmeter_setup_dbdma(struct rackmeter *rm)
 166 {
 167         struct rackmeter_dma *db = rm->dma_buf_v;
 168         struct dbdma_cmd *cmd = db->cmd;
 169
 170         /* Make sure dbdma is reset */
 171         DBDMA_DO_RESET(rm->dma_regs);
 172
 173         pr_debug("rackmeter: mark offset=0x%zx\n",
 174                  offsetof(struct rackmeter_dma, mark));
 175         pr_debug("rackmeter: buf1 offset=0x%zx\n",
 176                  offsetof(struct rackmeter_dma, buf1));
 177         pr_debug("rackmeter: buf2 offset=0x%zx\n",
 178                  offsetof(struct rackmeter_dma, buf2));
 179
 180         /* Prepare 4 dbdma commands for the 2 buffers */
 181         memset(cmd, 0, 4 * sizeof(struct dbdma_cmd));
 182         st_le16(&cmd->req_count, 4);
 183         st_le16(&cmd->command, STORE_WORD | INTR_ALWAYS | KEY_SYSTEM);
 184         st_le32(&cmd->phy_addr, rm->dma_buf_p +
 185                 offsetof(struct rackmeter_dma, mark));
 186         st_le32(&cmd->cmd_dep, 0x02000000);
 187         cmd++;
 188
 189         st_le16(&cmd->req_count, SAMPLE_COUNT * 4);
 190         st_le16(&cmd->command, OUTPUT_MORE);
 191         st_le32(&cmd->phy_addr, rm->dma_buf_p +
 192                 offsetof(struct rackmeter_dma, buf1));
 193         cmd++;
 194
 195         st_le16(&cmd->req_count, 4);
 196         st_le16(&cmd->command, STORE_WORD | INTR_ALWAYS | KEY_SYSTEM);
 197         st_le32(&cmd->phy_addr, rm->dma_buf_p +
 198                 offsetof(struct rackmeter_dma, mark));
 199         st_le32(&cmd->cmd_dep, 0x01000000);
 200         cmd++;
 201
 202         st_le16(&cmd->req_count, SAMPLE_COUNT * 4);
 203         st_le16(&cmd->command, OUTPUT_MORE | BR_ALWAYS);
 204         st_le32(&cmd->phy_addr, rm->dma_buf_p +
 205                 offsetof(struct rackmeter_dma, buf2));
 206         st_le32(&cmd->cmd_dep, rm->dma_buf_p);
 207
 208         rackmeter_do_pause(rm, 0);
 209 }
 210
 211 static void rackmeter_do_timer(struct work_struct *work)
 212 {
 213         struct rackmeter_cpu *rcpu =
 214                 container_of(work, struct rackmeter_cpu, sniffer.work);
 215         struct rackmeter *rm = rcpu->rm;
 216         unsigned int cpu = smp_processor_id();
 217         cputime64_t cur_jiffies, total_idle_ticks;
 218         unsigned int total_ticks, idle_ticks;
 219         int i, offset, load, cumm, pause;
 220
 221         cur_jiffies = jiffies64_to_cputime64(get_jiffies_64());
 222         total_ticks = (unsigned int)cputime64_sub(cur_jiffies,
 223                                                   rcpu->prev_wall);
 224         rcpu->prev_wall = cur_jiffies;
 225
 226         total_idle_ticks = get_cpu_idle_time(cpu);
 227         idle_ticks = (unsigned int) cputime64_sub(total_idle_ticks,
 228                                 rcpu->prev_idle);
 229         rcpu->prev_idle = total_idle_ticks;
 230
 231         /* We do a very dumb calculation to update the LEDs for now,
 232          * we'll do better once we have actual PWM implemented
 233          */
 234         load = (9 * (total_ticks - idle_ticks)) / total_ticks;
 235
 236         offset = cpu << 3;
 237         cumm = 0;
 238         for (i = 0; i < 8; i++) {
 239                 u8 ub = (load > i) ? 0xff : 0;
 240                 rm->ubuf[i + offset] = ub;
 241                 cumm |= ub;
 242         }
 243         rcpu->zero = (cumm == 0);
 244
 245         /* Now check if LEDs are all 0, we can stop DMA */
 246         pause = (rm->cpu[0].zero && rm->cpu[1].zero);
 247         if (pause != rm->paused) {
 248                 mutex_lock(&rm->sem);
 249                 pause = (rm->cpu[0].zero && rm->cpu[1].zero);
 250                 rackmeter_do_pause(rm, pause);
 251                 mutex_unlock(&rm->sem);
 252         }
 253         schedule_delayed_work_on(cpu, &rcpu->sniffer,
 254                                  msecs_to_jiffies(CPU_SAMPLING_RATE));
 255 }
 256
 257 static void __devinit rackmeter_init_cpu_sniffer(struct rackmeter *rm)
 258 {
 259         unsigned int cpu;
 260
 261         /* This driver works only with 1 or 2 CPUs numbered 0 and 1,
 262          * but that's really all we have on Apple Xserve. It doesn't
 263          * play very nice with CPU hotplug neither but we don't do that
 264          * on those machines yet
 265          */
 266
 267         rm->cpu[0].rm = rm;
 268         INIT_DELAYED_WORK(&rm->cpu[0].sniffer, rackmeter_do_timer);
 269         rm->cpu[1].rm = rm;
 270         INIT_DELAYED_WORK(&rm->cpu[1].sniffer, rackmeter_do_timer);
 271
 272         for_each_online_cpu(cpu) {
 273                 struct rackmeter_cpu *rcpu;
 274
 275                 if (cpu > 1)
 276                         continue;
 277                 rcpu = &rm->cpu[cpu];;
 278                 rcpu->prev_idle = get_cpu_idle_time(cpu);
 279                 rcpu->prev_wall = jiffies64_to_cputime64(get_jiffies_64());
 280                 schedule_delayed_work_on(cpu, &rm->cpu[cpu].sniffer,
 281                                          msecs_to_jiffies(CPU_SAMPLING_RATE));
 282         }
 283 }
 284
 285 static void __devexit rackmeter_stop_cpu_sniffer(struct rackmeter *rm)
 286 {
 287         cancel_rearming_delayed_work(&rm->cpu[0].sniffer);
 288         cancel_rearming_delayed_work(&rm->cpu[1].sniffer);
 289 }
 290
 291 static int rackmeter_setup(struct rackmeter *rm)
 292 {
 293         pr_debug("rackmeter: setting up i2s..\n");
 294         rackmeter_setup_i2s(rm);
 295
 296         pr_debug("rackmeter: setting up default pattern..\n");
 297         rackmeter_set_default_pattern(rm);
 298
 299         pr_debug("rackmeter: setting up dbdma..\n");
 300         rackmeter_setup_dbdma(rm);
 301
 302         pr_debug("rackmeter: start CPU measurements..\n");
 303         rackmeter_init_cpu_sniffer(rm);
 304
 305         printk(KERN_INFO "RackMeter initialized\n");
 306
 307         return 0;
 308 }
 309
 310 /*  XXX FIXME: No PWM yet, this is 0/1 */
 311 static 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
 323 static 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
 366 static 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 #if 0 /* Use that when i2s-a is finally an mdev per-se */
 410         if (macio_resource_count(mdev) < 2 || macio_irq_count(mdev) < 2) {
 411                 printk(KERN_ERR
 412                        "rackmeter: found match but lacks resources: %s"
 413                        " (%d resources, %d interrupts)\n",
 414                        mdev->ofdev.node->full_name);
 415                 rc = -ENXIO;
 416                 goto bail_free;
 417         }
 418         if (macio_request_resources(mdev, "rackmeter")) {
 419                 printk(KERN_ERR
 420                        "rackmeter: failed to request resources: %s\n",
 421                        mdev->ofdev.node->full_name);
 422                 rc = -EBUSY;
 423                 goto bail_free;
 424         }
 425         rm->irq = macio_irq(mdev, 1);
 426 #else
 427         rm->irq = irq_of_parse_and_map(i2s, 1);
 428         if (rm->irq == NO_IRQ ||
 429             of_address_to_resource(i2s, 0, &ri2s) ||
 430             of_address_to_resource(i2s, 1, &rdma)) {
 431                 printk(KERN_ERR
 432                        "rackmeter: found match but lacks resources: %s",
 433                        mdev->ofdev.node->full_name);
 434                 rc = -ENXIO;
 435                 goto bail_free;
 436         }
 437 #endif
 438
 439         pr_debug("  i2s @0x%08x\n", (unsigned int)ri2s.start);
 440         pr_debug("  dma @0x%08x\n", (unsigned int)rdma.start);
 441         pr_debug("  irq %d\n", rm->irq);
 442
 443         rm->ubuf = (u8 *)__get_free_page(GFP_KERNEL);
 444         if (rm->ubuf == NULL) {
 445                 printk(KERN_ERR
 446                        "rackmeter: failed to allocate samples page !\n");
 447                 rc = -ENOMEM;
 448                 goto bail_release;
 449         }
 450
 451         rm->dma_buf_v = dma_alloc_coherent(&macio_get_pci_dev(mdev)->dev,
 452                                            sizeof(struct rackmeter_dma),
 453                                            &rm->dma_buf_p, GFP_KERNEL);
 454         if (rm->dma_buf_v == NULL) {
 455                 printk(KERN_ERR
 456                        "rackmeter: failed to allocate dma buffer !\n");
 457                 rc = -ENOMEM;
 458                 goto bail_free_samples;
 459         }
 460 #if 0
 461         rm->i2s_regs = ioremap(macio_resource_start(mdev, 0), 0x1000);
 462 #else
 463         rm->i2s_regs = ioremap(ri2s.start, 0x1000);
 464 #endif
 465         if (rm->i2s_regs == NULL) {
 466                 printk(KERN_ERR
 467                        "rackmeter: failed to map i2s registers !\n");
 468                 rc = -ENXIO;
 469                 goto bail_free_dma;
 470         }
 471 #if 0
 472         rm->dma_regs = ioremap(macio_resource_start(mdev, 1), 0x100);
 473 #else
 474         rm->dma_regs = ioremap(rdma.start, 0x100);
 475 #endif
 476         if (rm->dma_regs == NULL) {
 477                 printk(KERN_ERR
 478                        "rackmeter: failed to map dma registers !\n");
 479                 rc = -ENXIO;
 480                 goto bail_unmap_i2s;
 481         }
 482
 483         rc = rackmeter_setup(rm);
 484         if (rc) {
 485                 printk(KERN_ERR
 486                        "rackmeter: failed to initialize !\n");
 487                 rc = -ENXIO;
 488                 goto bail_unmap_dma;
 489         }
 490
 491         rc = request_irq(rm->irq, rackmeter_irq, 0, "rackmeter", rm);
 492         if (rc != 0) {
 493                 printk(KERN_ERR
 494                        "rackmeter: failed to request interrupt !\n");
 495                 goto bail_stop_dma;
 496         }
 497         of_node_put(np);
 498         return 0;
 499
 500  bail_stop_dma:
 501         DBDMA_DO_RESET(rm->dma_regs);
 502  bail_unmap_dma:
 503         iounmap(rm->dma_regs);
 504  bail_unmap_i2s:
 505         iounmap(rm->i2s_regs);
 506  bail_free_dma:
 507         dma_free_coherent(&macio_get_pci_dev(mdev)->dev,
 508                           sizeof(struct rackmeter_dma),
 509                           rm->dma_buf_v, rm->dma_buf_p);
 510  bail_free_samples:
 511         free_page((unsigned long)rm->ubuf);
 512  bail_release:
 513 #if 0
 514         macio_release_resources(mdev);
 515 #endif
 516  bail_free:
 517         kfree(rm);
 518  bail:
 519         of_node_put(i2s);
 520         of_node_put(np);
 521         dev_set_drvdata(&mdev->ofdev.dev, NULL);
 522         return rc;
 523 }
 524
 525 static int __devexit rackmeter_remove(struct macio_dev* mdev)
 526 {
 527         struct rackmeter *rm = dev_get_drvdata(&mdev->ofdev.dev);
 528
 529         /* Stop CPU sniffer timer & work queues */
 530         rackmeter_stop_cpu_sniffer(rm);
 531
 532         /* Clear reference to private data */
 533         dev_set_drvdata(&mdev->ofdev.dev, NULL);
 534
 535         /* Stop/reset dbdma */
 536         DBDMA_DO_RESET(rm->dma_regs);
 537
 538         /* Release the IRQ */
 539         free_irq(rm->irq, rm);
 540
 541         /* Unmap registers */
 542         iounmap(rm->dma_regs);
 543         iounmap(rm->i2s_regs);
 544
 545         /* Free DMA */
 546         dma_free_coherent(&macio_get_pci_dev(mdev)->dev,
 547                           sizeof(struct rackmeter_dma),
 548                           rm->dma_buf_v, rm->dma_buf_p);
 549
 550         /* Free samples */
 551         free_page((unsigned long)rm->ubuf);
 552
 553 #if 0
 554         /* Release resources */
 555         macio_release_resources(mdev);
 556 #endif
 557
 558         /* Get rid of me */
 559         kfree(rm);
 560
 561         return 0;
 562 }
 563
 564 static int rackmeter_shutdown(struct macio_dev* mdev)
 565 {
 566         struct rackmeter *rm = dev_get_drvdata(&mdev->ofdev.dev);
 567
 568         if (rm == NULL)
 569                 return -ENODEV;
 570
 571         /* Stop CPU sniffer timer & work queues */
 572         rackmeter_stop_cpu_sniffer(rm);
 573
 574         /* Stop/reset dbdma */
 575         DBDMA_DO_RESET(rm->dma_regs);
 576
 577         return 0;
 578 }
 579
 580 static struct of_device_id rackmeter_match[] = {
 581         { .name = "i2s" },
 582         { }
 583 };
 584
 585 static struct macio_driver rackmeter_drv = {
 586         .name = "rackmeter",
 587         .owner = THIS_MODULE,
 588         .match_table = rackmeter_match,
 589         .probe = rackmeter_probe,
 590         .remove = rackmeter_remove,
 591         .shutdown = rackmeter_shutdown,
 592 };
 593
 594
 595 static int __init rackmeter_init(void)
 596 {
 597         pr_debug("rackmeter_init()\n");
 598
 599         return macio_register_driver(&rackmeter_drv);
 600 }
 601
 602 static void __exit rackmeter_exit(void)
 603 {
 604         pr_debug("rackmeter_exit()\n");
 605
 606         macio_unregister_driver(&rackmeter_drv);
 607 }
 608
 609 module_init(rackmeter_init);
 610 module_exit(rackmeter_exit);
 611
 612
 613 MODULE_LICENSE("GPL");
 614 MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
 615 MODULE_DESCRIPTION("RackMeter: Support vu-meter on XServe front panel");