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/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 	u64			prev_wall;
53 	u64			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  */
get_cpu_idle_time(unsigned int cpu)81 static inline u64 get_cpu_idle_time(unsigned int cpu)
82 {
83 	struct kernel_cpustat *kcpustat = &kcpustat_cpu(cpu);
84 	u64 retval;
85 
86 	retval = kcpustat->cpustat[CPUTIME_IDLE] +
87 		 kcpustat->cpustat[CPUTIME_IOWAIT];
88 
89 	if (rackmeter_ignore_nice)
90 		retval += kcpustat_field(kcpustat, CPUTIME_NICE, cpu);
91 
92 	return retval;
93 }
94 
rackmeter_setup_i2s(struct rackmeter * rm)95 static 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 
rackmeter_set_default_pattern(struct rackmeter * rm)132 static 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 
rackmeter_do_pause(struct rackmeter * rm,int pause)144 static 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, sizeof(rdma->buf1));
156 	memset(rdma->buf2, 0, sizeof(rdma->buf2));
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 
rackmeter_setup_dbdma(struct rackmeter * rm)166 static 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 	cmd->req_count = cpu_to_le16(4);
184 	cmd->command = cpu_to_le16(STORE_WORD | INTR_ALWAYS | KEY_SYSTEM);
185 	cmd->phy_addr = cpu_to_le32(rm->dma_buf_p +
186 		offsetof(struct rackmeter_dma, mark));
187 	cmd->cmd_dep = cpu_to_le32(0x02000000);
188 	cmd++;
189 
190 	cmd->req_count = cpu_to_le16(SAMPLE_COUNT * 4);
191 	cmd->command = cpu_to_le16(OUTPUT_MORE);
192 	cmd->phy_addr = cpu_to_le32(rm->dma_buf_p +
193 		offsetof(struct rackmeter_dma, buf1));
194 	cmd++;
195 
196 	cmd->req_count = cpu_to_le16(4);
197 	cmd->command = cpu_to_le16(STORE_WORD | INTR_ALWAYS | KEY_SYSTEM);
198 	cmd->phy_addr = cpu_to_le32(rm->dma_buf_p +
199 		offsetof(struct rackmeter_dma, mark));
200 	cmd->cmd_dep = cpu_to_le32(0x01000000);
201 	cmd++;
202 
203 	cmd->req_count = cpu_to_le16(SAMPLE_COUNT * 4);
204 	cmd->command = cpu_to_le16(OUTPUT_MORE | BR_ALWAYS);
205 	cmd->phy_addr = cpu_to_le32(rm->dma_buf_p +
206 		offsetof(struct rackmeter_dma, buf2));
207 	cmd->cmd_dep = cpu_to_le32(rm->dma_buf_p);
208 
209 	rackmeter_do_pause(rm, 0);
210 }
211 
rackmeter_do_timer(struct work_struct * work)212 static 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 	u64 cur_nsecs, total_idle_nsecs;
219 	u64 total_nsecs, idle_nsecs;
220 	int i, offset, load, cumm, pause;
221 
222 	cur_nsecs = jiffies64_to_nsecs(get_jiffies_64());
223 	total_nsecs = cur_nsecs - rcpu->prev_wall;
224 	rcpu->prev_wall = cur_nsecs;
225 
226 	total_idle_nsecs = get_cpu_idle_time(cpu);
227 	idle_nsecs = total_idle_nsecs - rcpu->prev_idle;
228 	idle_nsecs = min(idle_nsecs, total_nsecs);
229 	rcpu->prev_idle = total_idle_nsecs;
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 = div64_u64(9 * (total_nsecs - idle_nsecs), total_nsecs);
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 
rackmeter_init_cpu_sniffer(struct rackmeter * rm)257 static void 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_nsecs(get_jiffies_64());
280 		schedule_delayed_work_on(cpu, &rm->cpu[cpu].sniffer,
281 					 msecs_to_jiffies(CPU_SAMPLING_RATE));
282 	}
283 }
284 
rackmeter_stop_cpu_sniffer(struct rackmeter * rm)285 static void rackmeter_stop_cpu_sniffer(struct rackmeter *rm)
286 {
287 	cancel_delayed_work_sync(&rm->cpu[0].sniffer);
288 	cancel_delayed_work_sync(&rm->cpu[1].sniffer);
289 }
290 
rackmeter_setup(struct rackmeter * rm)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 */
rackmeter_calc_sample(struct rackmeter * rm,unsigned int index)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 
rackmeter_irq(int irq,void * arg)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 
rackmeter_probe(struct macio_dev * mdev,const struct of_device_id * match)366 static int 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 	for_each_child_of_node(mdev->ofdev.dev.of_node, i2s)
378 		if (of_node_name_eq(i2s, "i2s-a"))
379 			break;
380 
381 	if (i2s == NULL) {
382 		pr_debug("  i2s-a child not found\n");
383 		goto bail;
384 	}
385 	/* Get lightshow or virtual sound */
386 	for_each_child_of_node(i2s, np) {
387 	       if (of_node_name_eq(np, "lightshow"))
388 		       break;
389 	       if (of_node_name_eq(np, "sound") &&
390 		   of_property_present(np, "virtual"))
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(*rm), 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: %pOF"
414 		       " (%d resources, %d interrupts)\n",
415 		       mdev->ofdev.dev.of_node);
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: %pOF\n",
422 		       mdev->ofdev.dev.of_node);
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 ||
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: %pOF",
434 		       mdev->ofdev.dev.of_node);
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 
rackmeter_remove(struct macio_dev * mdev)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 
rackmeter_shutdown(struct macio_dev * mdev)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 const struct of_device_id rackmeter_match[] = {
582 	{ .name = "i2s" },
583 	{ }
584 };
585 MODULE_DEVICE_TABLE(of, rackmeter_match);
586 
587 static struct macio_driver rackmeter_driver = {
588 	.driver = {
589 		.name = "rackmeter",
590 		.owner = THIS_MODULE,
591 		.of_match_table = rackmeter_match,
592 	},
593 	.probe = rackmeter_probe,
594 	.remove = rackmeter_remove,
595 	.shutdown = rackmeter_shutdown,
596 };
597 
598 
rackmeter_init(void)599 static int __init rackmeter_init(void)
600 {
601 	pr_debug("rackmeter_init()\n");
602 
603 	return macio_register_driver(&rackmeter_driver);
604 }
605 
rackmeter_exit(void)606 static void __exit rackmeter_exit(void)
607 {
608 	pr_debug("rackmeter_exit()\n");
609 
610 	macio_unregister_driver(&rackmeter_driver);
611 }
612 
613 module_init(rackmeter_init);
614 module_exit(rackmeter_exit);
615 
616 
617 MODULE_LICENSE("GPL");
618 MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
619 MODULE_DESCRIPTION("RackMeter: Support vu-meter on XServe front panel");
620