rack-meter.c revision 648616343cdbe904c585a6c12e323d3b3c72e46f 
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
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
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 = kstat_cpu(cpu).cpustat.idle + kstat_cpu(cpu).cpustat.iowait;
87
88	if (rackmeter_ignore_nice)
89		retval += kstat_cpu(cpu).cpustat.nice;
90
91	return retval;
92}
93
94static 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
131static 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
143static 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
165static 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
211static 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) (cur_jiffies - rcpu->prev_wall);
223	rcpu->prev_wall = cur_jiffies;
224
225	total_idle_ticks = get_cpu_idle_time(cpu);
226	idle_ticks = (unsigned int) (total_idle_ticks - rcpu->prev_idle);
227	rcpu->prev_idle = total_idle_ticks;
228
229	/* We do a very dumb calculation to update the LEDs for now,
230	 * we'll do better once we have actual PWM implemented
231	 */
232	load = (9 * (total_ticks - idle_ticks)) / total_ticks;
233
234	offset = cpu << 3;
235	cumm = 0;
236	for (i = 0; i < 8; i++) {
237		u8 ub = (load > i) ? 0xff : 0;
238		rm->ubuf[i + offset] = ub;
239		cumm |= ub;
240	}
241	rcpu->zero = (cumm == 0);
242
243	/* Now check if LEDs are all 0, we can stop DMA */
244	pause = (rm->cpu[0].zero && rm->cpu[1].zero);
245	if (pause != rm->paused) {
246		mutex_lock(&rm->sem);
247		pause = (rm->cpu[0].zero && rm->cpu[1].zero);
248		rackmeter_do_pause(rm, pause);
249		mutex_unlock(&rm->sem);
250	}
251	schedule_delayed_work_on(cpu, &rcpu->sniffer,
252				 msecs_to_jiffies(CPU_SAMPLING_RATE));
253}
254
255static void __devinit rackmeter_init_cpu_sniffer(struct rackmeter *rm)
256{
257	unsigned int cpu;
258
259	/* This driver works only with 1 or 2 CPUs numbered 0 and 1,
260	 * but that's really all we have on Apple Xserve. It doesn't
261	 * play very nice with CPU hotplug neither but we don't do that
262	 * on those machines yet
263	 */
264
265	rm->cpu[0].rm = rm;
266	INIT_DELAYED_WORK(&rm->cpu[0].sniffer, rackmeter_do_timer);
267	rm->cpu[1].rm = rm;
268	INIT_DELAYED_WORK(&rm->cpu[1].sniffer, rackmeter_do_timer);
269
270	for_each_online_cpu(cpu) {
271		struct rackmeter_cpu *rcpu;
272
273		if (cpu > 1)
274			continue;
275		rcpu = &rm->cpu[cpu];
276		rcpu->prev_idle = get_cpu_idle_time(cpu);
277		rcpu->prev_wall = jiffies64_to_cputime64(get_jiffies_64());
278		schedule_delayed_work_on(cpu, &rm->cpu[cpu].sniffer,
279					 msecs_to_jiffies(CPU_SAMPLING_RATE));
280	}
281}
282
283static void rackmeter_stop_cpu_sniffer(struct rackmeter *rm)
284{
285	cancel_delayed_work_sync(&rm->cpu[0].sniffer);
286	cancel_delayed_work_sync(&rm->cpu[1].sniffer);
287}
288
289static int __devinit rackmeter_setup(struct rackmeter *rm)
290{
291	pr_debug("rackmeter: setting up i2s..\n");
292	rackmeter_setup_i2s(rm);
293
294	pr_debug("rackmeter: setting up default pattern..\n");
295	rackmeter_set_default_pattern(rm);
296
297	pr_debug("rackmeter: setting up dbdma..\n");
298	rackmeter_setup_dbdma(rm);
299
300	pr_debug("rackmeter: start CPU measurements..\n");
301	rackmeter_init_cpu_sniffer(rm);
302
303	printk(KERN_INFO "RackMeter initialized\n");
304
305	return 0;
306}
307
308/*  XXX FIXME: No PWM yet, this is 0/1 */
309static u32 rackmeter_calc_sample(struct rackmeter *rm, unsigned int index)
310{
311	int led;
312	u32 sample = 0;
313
314	for (led = 0; led < 16; led++) {
315		sample >>= 1;
316		sample |= ((rm->ubuf[led] >= 0x80) << 15);
317	}
318	return (sample << 17) | (sample >> 15);
319}
320
321static irqreturn_t rackmeter_irq(int irq, void *arg)
322{
323	struct rackmeter *rm = arg;
324	struct rackmeter_dma *db = rm->dma_buf_v;
325	unsigned int mark, i;
326	u32 *buf;
327
328	/* Flush PCI buffers with an MMIO read. Maybe we could actually
329	 * check the status one day ... in case things go wrong, though
330	 * this never happened to me
331	 */
332	(void)in_le32(&rm->dma_regs->status);
333
334	/* Make sure the CPU gets us in order */
335	rmb();
336
337	/* Read mark */
338	mark = db->mark;
339	if (mark != 1 && mark != 2) {
340		printk(KERN_WARNING "rackmeter: Incorrect DMA mark 0x%08x\n",
341		       mark);
342		/* We allow for 3 errors like that (stale DBDMA irqs) */
343		if (++rm->stale_irq > 3) {
344			printk(KERN_ERR "rackmeter: Too many errors,"
345			       " stopping DMA\n");
346			DBDMA_DO_RESET(rm->dma_regs);
347		}
348		return IRQ_HANDLED;
349	}
350
351	/* Next buffer we need to fill is mark value */
352	buf = mark == 1 ? db->buf1 : db->buf2;
353
354	/* Fill it now. This routine converts the 8 bits depth sample array
355	 * into the PWM bitmap for each LED.
356	 */
357	for (i = 0; i < SAMPLE_COUNT; i++)
358		buf[i] = rackmeter_calc_sample(rm, i);
359
360
361	return IRQ_HANDLED;
362}
363
364static int __devinit rackmeter_probe(struct macio_dev* mdev,
365				     const struct of_device_id *match)
366{
367	struct device_node *i2s = NULL, *np = NULL;
368	struct rackmeter *rm = NULL;
369	struct resource ri2s, rdma;
370	int rc = -ENODEV;
371
372	pr_debug("rackmeter_probe()\n");
373
374	/* Get i2s-a node */
375	while ((i2s = of_get_next_child(mdev->ofdev.dev.of_node, i2s)) != NULL)
376	       if (strcmp(i2s->name, "i2s-a") == 0)
377		       break;
378	if (i2s == NULL) {
379		pr_debug("  i2s-a child not found\n");
380		goto bail;
381	}
382	/* Get lightshow or virtual sound */
383	while ((np = of_get_next_child(i2s, np)) != NULL) {
384	       if (strcmp(np->name, "lightshow") == 0)
385		       break;
386	       if ((strcmp(np->name, "sound") == 0) &&
387		   of_get_property(np, "virtual", NULL) != NULL)
388		       break;
389	}
390	if (np == NULL) {
391		pr_debug("  lightshow or sound+virtual child not found\n");
392		goto bail;
393	}
394
395	/* Create and initialize our instance data */
396	rm = kzalloc(sizeof(struct rackmeter), GFP_KERNEL);
397	if (rm == NULL) {
398		printk(KERN_ERR "rackmeter: failed to allocate memory !\n");
399		rc = -ENOMEM;
400		goto bail_release;
401	}
402	rm->mdev = mdev;
403	rm->i2s = i2s;
404	mutex_init(&rm->sem);
405	dev_set_drvdata(&mdev->ofdev.dev, rm);
406	/* Check resources availability. We need at least resource 0 and 1 */
407#if 0 /* Use that when i2s-a is finally an mdev per-se */
408	if (macio_resource_count(mdev) < 2 || macio_irq_count(mdev) < 2) {
409		printk(KERN_ERR
410		       "rackmeter: found match but lacks resources: %s"
411		       " (%d resources, %d interrupts)\n",
412		       mdev->ofdev.node->full_name);
413		rc = -ENXIO;
414		goto bail_free;
415	}
416	if (macio_request_resources(mdev, "rackmeter")) {
417		printk(KERN_ERR
418		       "rackmeter: failed to request resources: %s\n",
419		       mdev->ofdev.node->full_name);
420		rc = -EBUSY;
421		goto bail_free;
422	}
423	rm->irq = macio_irq(mdev, 1);
424#else
425	rm->irq = irq_of_parse_and_map(i2s, 1);
426	if (rm->irq == NO_IRQ ||
427	    of_address_to_resource(i2s, 0, &ri2s) ||
428	    of_address_to_resource(i2s, 1, &rdma)) {
429		printk(KERN_ERR
430		       "rackmeter: found match but lacks resources: %s",
431		       mdev->ofdev.dev.of_node->full_name);
432		rc = -ENXIO;
433		goto bail_free;
434	}
435#endif
436
437	pr_debug("  i2s @0x%08x\n", (unsigned int)ri2s.start);
438	pr_debug("  dma @0x%08x\n", (unsigned int)rdma.start);
439	pr_debug("  irq %d\n", rm->irq);
440
441	rm->ubuf = (u8 *)__get_free_page(GFP_KERNEL);
442	if (rm->ubuf == NULL) {
443		printk(KERN_ERR
444		       "rackmeter: failed to allocate samples page !\n");
445		rc = -ENOMEM;
446		goto bail_release;
447	}
448
449	rm->dma_buf_v = dma_alloc_coherent(&macio_get_pci_dev(mdev)->dev,
450					   sizeof(struct rackmeter_dma),
451					   &rm->dma_buf_p, GFP_KERNEL);
452	if (rm->dma_buf_v == NULL) {
453		printk(KERN_ERR
454		       "rackmeter: failed to allocate dma buffer !\n");
455		rc = -ENOMEM;
456		goto bail_free_samples;
457	}
458#if 0
459	rm->i2s_regs = ioremap(macio_resource_start(mdev, 0), 0x1000);
460#else
461	rm->i2s_regs = ioremap(ri2s.start, 0x1000);
462#endif
463	if (rm->i2s_regs == NULL) {
464		printk(KERN_ERR
465		       "rackmeter: failed to map i2s registers !\n");
466		rc = -ENXIO;
467		goto bail_free_dma;
468	}
469#if 0
470	rm->dma_regs = ioremap(macio_resource_start(mdev, 1), 0x100);
471#else
472	rm->dma_regs = ioremap(rdma.start, 0x100);
473#endif
474	if (rm->dma_regs == NULL) {
475		printk(KERN_ERR
476		       "rackmeter: failed to map dma registers !\n");
477		rc = -ENXIO;
478		goto bail_unmap_i2s;
479	}
480
481	rc = rackmeter_setup(rm);
482	if (rc) {
483		printk(KERN_ERR
484		       "rackmeter: failed to initialize !\n");
485		rc = -ENXIO;
486		goto bail_unmap_dma;
487	}
488
489	rc = request_irq(rm->irq, rackmeter_irq, 0, "rackmeter", rm);
490	if (rc != 0) {
491		printk(KERN_ERR
492		       "rackmeter: failed to request interrupt !\n");
493		goto bail_stop_dma;
494	}
495	of_node_put(np);
496	return 0;
497
498 bail_stop_dma:
499	DBDMA_DO_RESET(rm->dma_regs);
500 bail_unmap_dma:
501	iounmap(rm->dma_regs);
502 bail_unmap_i2s:
503	iounmap(rm->i2s_regs);
504 bail_free_dma:
505	dma_free_coherent(&macio_get_pci_dev(mdev)->dev,
506			  sizeof(struct rackmeter_dma),
507			  rm->dma_buf_v, rm->dma_buf_p);
508 bail_free_samples:
509	free_page((unsigned long)rm->ubuf);
510 bail_release:
511#if 0
512	macio_release_resources(mdev);
513#endif
514 bail_free:
515	kfree(rm);
516 bail:
517	of_node_put(i2s);
518	of_node_put(np);
519	dev_set_drvdata(&mdev->ofdev.dev, NULL);
520	return rc;
521}
522
523static int __devexit rackmeter_remove(struct macio_dev* mdev)
524{
525	struct rackmeter *rm = dev_get_drvdata(&mdev->ofdev.dev);
526
527	/* Stop CPU sniffer timer & work queues */
528	rackmeter_stop_cpu_sniffer(rm);
529
530	/* Clear reference to private data */
531	dev_set_drvdata(&mdev->ofdev.dev, NULL);
532
533	/* Stop/reset dbdma */
534	DBDMA_DO_RESET(rm->dma_regs);
535
536	/* Release the IRQ */
537	free_irq(rm->irq, rm);
538
539	/* Unmap registers */
540	iounmap(rm->dma_regs);
541	iounmap(rm->i2s_regs);
542
543	/* Free DMA */
544	dma_free_coherent(&macio_get_pci_dev(mdev)->dev,
545			  sizeof(struct rackmeter_dma),
546			  rm->dma_buf_v, rm->dma_buf_p);
547
548	/* Free samples */
549	free_page((unsigned long)rm->ubuf);
550
551#if 0
552	/* Release resources */
553	macio_release_resources(mdev);
554#endif
555
556	/* Get rid of me */
557	kfree(rm);
558
559	return 0;
560}
561
562static int rackmeter_shutdown(struct macio_dev* mdev)
563{
564	struct rackmeter *rm = dev_get_drvdata(&mdev->ofdev.dev);
565
566	if (rm == NULL)
567		return -ENODEV;
568
569	/* Stop CPU sniffer timer & work queues */
570	rackmeter_stop_cpu_sniffer(rm);
571
572	/* Stop/reset dbdma */
573	DBDMA_DO_RESET(rm->dma_regs);
574
575	return 0;
576}
577
578static struct of_device_id rackmeter_match[] = {
579	{ .name = "i2s" },
580	{ }
581};
582
583static struct macio_driver rackmeter_driver = {
584	.driver = {
585		.name = "rackmeter",
586		.owner = THIS_MODULE,
587		.of_match_table = rackmeter_match,
588	},
589	.probe = rackmeter_probe,
590	.remove = __devexit_p(rackmeter_remove),
591	.shutdown = rackmeter_shutdown,
592};
593
594
595static int __init rackmeter_init(void)
596{
597	pr_debug("rackmeter_init()\n");
598
599	return macio_register_driver(&rackmeter_driver);
600}
601
602static void __exit rackmeter_exit(void)
603{
604	pr_debug("rackmeter_exit()\n");
605
606	macio_unregister_driver(&rackmeter_driver);
607}
608
609module_init(rackmeter_init);
610module_exit(rackmeter_exit);
611
612
613MODULE_LICENSE("GPL");
614MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
615MODULE_DESCRIPTION("RackMeter: Support vu-meter on XServe front panel");
616