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/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         u64                     prev_wall;
  56         u64                     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 u64 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         u64 cur_nsecs, total_idle_nsecs;
 221         u64 total_nsecs, idle_nsecs;
 222         int i, offset, load, cumm, pause;
 223
 224         cur_nsecs = jiffies64_to_nsecs(get_jiffies_64());
 225         total_nsecs = cur_nsecs - rcpu->prev_wall;
 226         rcpu->prev_wall = cur_nsecs;
 227
 228         total_idle_nsecs = get_cpu_idle_time(cpu);
 229         idle_nsecs = total_idle_nsecs - rcpu->prev_idle;
 230         idle_nsecs = min(idle_nsecs, total_nsecs);
 231         rcpu->prev_idle = total_idle_nsecs;
 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 = div64_u64(9 * (total_nsecs - idle_nsecs), total_nsecs);
 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_nsecs(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: %pOF"
 415                        " (%d resources, %d interrupts)\n",
 416                        mdev->ofdev.dev.of_node);
 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: %pOF\n",
 423                        mdev->ofdev.dev.of_node);
 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 ||
 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: %pOF",
 435                        mdev->ofdev.dev.of_node);
 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 const 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");