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
45struct 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
52struct rackmeter_cpu {
53	struct delayed_work	sniffer;
54	struct rackmeter	*rm;
55	cputime64_t		prev_wall;
56	cputime64_t		prev_idle;
57	int			zero;
58} ____cacheline_aligned;
59
60struct 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 */
76static 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 */
84static inline cputime64_t 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
97static 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
134static 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
146static 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, SAMPLE_COUNT & sizeof(u32));
158	memset(rdma->buf2, 0, SAMPLE_COUNT & sizeof(u32));
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
168static 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	st_le16(&cmd->req_count, 4);
186	st_le16(&cmd->command, STORE_WORD | INTR_ALWAYS | KEY_SYSTEM);
187	st_le32(&cmd->phy_addr, rm->dma_buf_p +
188		offsetof(struct rackmeter_dma, mark));
189	st_le32(&cmd->cmd_dep, 0x02000000);
190	cmd++;
191
192	st_le16(&cmd->req_count, SAMPLE_COUNT * 4);
193	st_le16(&cmd->command, OUTPUT_MORE);
194	st_le32(&cmd->phy_addr, rm->dma_buf_p +
195		offsetof(struct rackmeter_dma, buf1));
196	cmd++;
197
198	st_le16(&cmd->req_count, 4);
199	st_le16(&cmd->command, STORE_WORD | INTR_ALWAYS | KEY_SYSTEM);
200	st_le32(&cmd->phy_addr, rm->dma_buf_p +
201		offsetof(struct rackmeter_dma, mark));
202	st_le32(&cmd->cmd_dep, 0x01000000);
203	cmd++;
204
205	st_le16(&cmd->req_count, SAMPLE_COUNT * 4);
206	st_le16(&cmd->command, OUTPUT_MORE | BR_ALWAYS);
207	st_le32(&cmd->phy_addr, rm->dma_buf_p +
208		offsetof(struct rackmeter_dma, buf2));
209	st_le32(&cmd->cmd_dep, rm->dma_buf_p);
210
211	rackmeter_do_pause(rm, 0);
212}
213
214static 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	cputime64_t cur_jiffies, total_idle_ticks;
221	unsigned int total_ticks, idle_ticks;
222	int i, offset, load, cumm, pause;
223
224	cur_jiffies = jiffies64_to_cputime64(get_jiffies_64());
225	total_ticks = (unsigned int) (cur_jiffies - rcpu->prev_wall);
226	rcpu->prev_wall = cur_jiffies;
227
228	total_idle_ticks = get_cpu_idle_time(cpu);
229	idle_ticks = (unsigned int) (total_idle_ticks - rcpu->prev_idle);
230	rcpu->prev_idle = total_idle_ticks;
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 = (9 * (total_ticks - idle_ticks)) / total_ticks;
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
258static 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_cputime64(get_jiffies_64());
281		schedule_delayed_work_on(cpu, &rm->cpu[cpu].sniffer,
282					 msecs_to_jiffies(CPU_SAMPLING_RATE));
283	}
284}
285
286static 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
292static 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 */
312static 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
324static 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
367static 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	while ((i2s = of_get_next_child(mdev->ofdev.dev.of_node, i2s)) != NULL)
379	       if (strcmp(i2s->name, "i2s-a") == 0)
380		       break;
381	if (i2s == NULL) {
382		pr_debug("  i2s-a child not found\n");
383		goto bail;
384	}
385	/* Get lightshow or virtual sound */
386	while ((np = of_get_next_child(i2s, np)) != NULL) {
387	       if (strcmp(np->name, "lightshow") == 0)
388		       break;
389	       if ((strcmp(np->name, "sound") == 0) &&
390		   of_get_property(np, "virtual", NULL) != NULL)
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(struct rackmeter), 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: %s"
414		       " (%d resources, %d interrupts)\n",
415		       mdev->ofdev.node->full_name);
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: %s\n",
422		       mdev->ofdev.node->full_name);
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 == NO_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: %s",
434		       mdev->ofdev.dev.of_node->full_name);
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
526static 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
565static 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
581static struct of_device_id rackmeter_match[] = {
582	{ .name = "i2s" },
583	{ }
584};
585
586static struct macio_driver rackmeter_driver = {
587	.driver = {
588		.name = "rackmeter",
589		.owner = THIS_MODULE,
590		.of_match_table = rackmeter_match,
591	},
592	.probe = rackmeter_probe,
593	.remove = rackmeter_remove,
594	.shutdown = rackmeter_shutdown,
595};
596
597
598static int __init rackmeter_init(void)
599{
600	pr_debug("rackmeter_init()\n");
601
602	return macio_register_driver(&rackmeter_driver);
603}
604
605static void __exit rackmeter_exit(void)
606{
607	pr_debug("rackmeter_exit()\n");
608
609	macio_unregister_driver(&rackmeter_driver);
610}
611
612module_init(rackmeter_init);
613module_exit(rackmeter_exit);
614
615
616MODULE_LICENSE("GPL");
617MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
618MODULE_DESCRIPTION("RackMeter: Support vu-meter on XServe front panel");
619