drivers/macintosh/rack-meter.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * RackMac vu-meter driver
   4  *
   5  * (c) Copyright 2006 Benjamin Herrenschmidt, IBM Corp.
   6  *                    <benh@kernel.crashing.org>
   7  *
   8  * Support the CPU-meter LEDs of the Xserve G5
   9  *
  10  * TODO: Implement PWM to do variable intensity and provide userland
  11  * interface for fun. Also, the CPU-meter could be made nicer by being
  12  * a bit less "immediate" but giving instead a more average load over
  13  * time. Patches welcome :-)
  14  */
  15 #undef DEBUG
  16
  17 #include <linux/types.h>
  18 #include <linux/kernel.h>
  19 #include <linux/slab.h>
  20 #include <linux/device.h>
  21 #include <linux/interrupt.h>
  22 #include <linux/module.h>
  23 #include <linux/pci.h>
  24 #include <linux/dma-mapping.h>
  25 #include <linux/kernel_stat.h>
  26 #include <linux/of_address.h>
  27 #include <linux/of_irq.h>
  28
  29 #include <asm/io.h>
  30 #include <asm/prom.h>
  31 #include <asm/machdep.h>
  32 #include <asm/pmac_feature.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
  43 struct 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
  50 struct rackmeter_cpu {
  51         struct delayed_work     sniffer;
  52         struct rackmeter        *rm;
  53         u64                     prev_wall;
  54         u64                     prev_idle;
  55         int                     zero;
  56 } ____cacheline_aligned;
  57
  58 struct 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 */
  74 static 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  */
  82 static inline u64 get_cpu_idle_time(unsigned int cpu)
  83 {
  84         struct kernel_cpustat *kcpustat = &kcpustat_cpu(cpu);
  85         u64 retval;
  86
  87         retval = kcpustat->cpustat[CPUTIME_IDLE] +
  88                  kcpustat->cpustat[CPUTIME_IOWAIT];
  89
  90         if (rackmeter_ignore_nice)
  91                 retval += kcpustat_field(kcpustat, CPUTIME_NICE, cpu);
  92
  93         return retval;
  94 }
  95
  96 static void rackmeter_setup_i2s(struct rackmeter *rm)
  97 {
  98         struct macio_chip *macio = rm->mdev->bus->chip;
  99
 100         /* First whack magic GPIO */
 101         pmac_call_feature(PMAC_FTR_WRITE_GPIO, NULL, RACKMETER_MAGIC_GPIO, 5);
 102
 103
 104         /* Call feature code to enable the sound channel and the proper
 105          * clock sources
 106          */
 107         pmac_call_feature(PMAC_FTR_SOUND_CHIP_ENABLE, rm->i2s, 0, 1);
 108
 109         /* Power i2s and stop i2s clock. We whack MacIO FCRs directly for now.
 110          * This is a bit racy, thus we should add new platform functions to
 111          * handle that. snd-aoa needs that too
 112          */
 113         MACIO_BIS(KEYLARGO_FCR1, KL1_I2S0_ENABLE);
 114         MACIO_BIC(KEYLARGO_FCR1, KL1_I2S0_CLK_ENABLE_BIT);
 115         (void)MACIO_IN32(KEYLARGO_FCR1);
 116         udelay(10);
 117
 118         /* Then setup i2s. For now, we use the same magic value that
 119          * the OS X driver seems to use. We might want to play around
 120          * with the clock divisors later
 121          */
 122         out_le32(rm->i2s_regs + 0x10, 0x01fa0000);
 123         (void)in_le32(rm->i2s_regs + 0x10);
 124         udelay(10);
 125
 126         /* Fully restart i2s*/
 127         MACIO_BIS(KEYLARGO_FCR1, KL1_I2S0_CELL_ENABLE |
 128                   KL1_I2S0_CLK_ENABLE_BIT);
 129         (void)MACIO_IN32(KEYLARGO_FCR1);
 130         udelay(10);
 131 }
 132
 133 static void rackmeter_set_default_pattern(struct rackmeter *rm)
 134 {
 135         int i;
 136
 137         for (i = 0; i < 16; i++) {
 138                 if (i < 8)
 139                         rm->ubuf[i] = (i & 1) * 255;
 140                 else
 141                         rm->ubuf[i] = ((~i) & 1) * 255;
 142         }
 143 }
 144
 145 static void rackmeter_do_pause(struct rackmeter *rm, int pause)
 146 {
 147         struct rackmeter_dma *rdma = rm->dma_buf_v;
 148
 149         pr_debug("rackmeter: %s\n", pause ? "paused" : "started");
 150
 151         rm->paused = pause;
 152         if (pause) {
 153                 DBDMA_DO_STOP(rm->dma_regs);
 154                 return;
 155         }
 156         memset(rdma->buf1, 0, sizeof(rdma->buf1));
 157         memset(rdma->buf2, 0, sizeof(rdma->buf2));
 158
 159         rm->dma_buf_v->mark = 0;
 160
 161         mb();
 162         out_le32(&rm->dma_regs->cmdptr_hi, 0);
 163         out_le32(&rm->dma_regs->cmdptr, rm->dma_buf_p);
 164         out_le32(&rm->dma_regs->control, (RUN << 16) | RUN);
 165 }
 166
 167 static void rackmeter_setup_dbdma(struct rackmeter *rm)
 168 {
 169         struct rackmeter_dma *db = rm->dma_buf_v;
 170         struct dbdma_cmd *cmd = db->cmd;
 171
 172         /* Make sure dbdma is reset */
 173         DBDMA_DO_RESET(rm->dma_regs);
 174
 175         pr_debug("rackmeter: mark offset=0x%zx\n",
 176                  offsetof(struct rackmeter_dma, mark));
 177         pr_debug("rackmeter: buf1 offset=0x%zx\n",
 178                  offsetof(struct rackmeter_dma, buf1));
 179         pr_debug("rackmeter: buf2 offset=0x%zx\n",
 180                  offsetof(struct rackmeter_dma, buf2));
 181
 182         /* Prepare 4 dbdma commands for the 2 buffers */
 183         memset(cmd, 0, 4 * sizeof(struct dbdma_cmd));
 184         cmd->req_count = cpu_to_le16(4);
 185         cmd->command = cpu_to_le16(STORE_WORD | INTR_ALWAYS | KEY_SYSTEM);
 186         cmd->phy_addr = cpu_to_le32(rm->dma_buf_p +
 187                 offsetof(struct rackmeter_dma, mark));
 188         cmd->cmd_dep = cpu_to_le32(0x02000000);
 189         cmd++;
 190
 191         cmd->req_count = cpu_to_le16(SAMPLE_COUNT * 4);
 192         cmd->command = cpu_to_le16(OUTPUT_MORE);
 193         cmd->phy_addr = cpu_to_le32(rm->dma_buf_p +
 194                 offsetof(struct rackmeter_dma, buf1));
 195         cmd++;
 196
 197         cmd->req_count = cpu_to_le16(4);
 198         cmd->command = cpu_to_le16(STORE_WORD | INTR_ALWAYS | KEY_SYSTEM);
 199         cmd->phy_addr = cpu_to_le32(rm->dma_buf_p +
 200                 offsetof(struct rackmeter_dma, mark));
 201         cmd->cmd_dep = cpu_to_le32(0x01000000);
 202         cmd++;
 203
 204         cmd->req_count = cpu_to_le16(SAMPLE_COUNT * 4);
 205         cmd->command = cpu_to_le16(OUTPUT_MORE | BR_ALWAYS);
 206         cmd->phy_addr = cpu_to_le32(rm->dma_buf_p +
 207                 offsetof(struct rackmeter_dma, buf2));
 208         cmd->cmd_dep = cpu_to_le32(rm->dma_buf_p);
 209
 210         rackmeter_do_pause(rm, 0);
 211 }
 212
 213 static void rackmeter_do_timer(struct work_struct *work)
 214 {
 215         struct rackmeter_cpu *rcpu =
 216                 container_of(work, struct rackmeter_cpu, sniffer.work);
 217         struct rackmeter *rm = rcpu->rm;
 218         unsigned int cpu = smp_processor_id();
 219         u64 cur_nsecs, total_idle_nsecs;
 220         u64 total_nsecs, idle_nsecs;
 221         int i, offset, load, cumm, pause;
 222
 223         cur_nsecs = jiffies64_to_nsecs(get_jiffies_64());
 224         total_nsecs = cur_nsecs - rcpu->prev_wall;
 225         rcpu->prev_wall = cur_nsecs;
 226
 227         total_idle_nsecs = get_cpu_idle_time(cpu);
 228         idle_nsecs = total_idle_nsecs - rcpu->prev_idle;
 229         idle_nsecs = min(idle_nsecs, total_nsecs);
 230         rcpu->prev_idle = total_idle_nsecs;
 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 = div64_u64(9 * (total_nsecs - idle_nsecs), total_nsecs);
 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_nsecs(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         for_each_child_of_node(mdev->ofdev.dev.of_node, i2s)
 379                 if (of_node_name_eq(i2s, "i2s-a"))
 380                         break;
 381
 382         if (i2s == NULL) {
 383                 pr_debug("  i2s-a child not found\n");
 384                 goto bail;
 385         }
 386         /* Get lightshow or virtual sound */
 387         for_each_child_of_node(i2s, np) {
 388                if (of_node_name_eq(np, "lightshow"))
 389                        break;
 390                if (of_node_name_eq(np, "sound") &&
 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(*rm), 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");