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/device.h>
22#include <linux/interrupt.h>
23#include <linux/module.h>
24#include <linux/pci.h>
25#include <linux/dma-mapping.h>
26#include <linux/kernel_stat.h>
27
28#include <asm/io.h>
29#include <asm/prom.h>
30#include <asm/machdep.h>
31#include <asm/pmac_feature.h>
32#include <asm/dbdma.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 = cputime64_add(kstat_cpu(cpu).cpustat.idle,
87			kstat_cpu(cpu).cpustat.iowait);
88
89	if (rackmeter_ignore_nice)
90		retval = cputime64_add(retval, kstat_cpu(cpu).cpustat.nice);
91
92	return retval;
93}
94
95static 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
132static 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
144static 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, SAMPLE_COUNT & sizeof(u32));
156	memset(rdma->buf2, 0, SAMPLE_COUNT & sizeof(u32));
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
166static 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	st_le16(&cmd->req_count, 4);
184	st_le16(&cmd->command, STORE_WORD | INTR_ALWAYS | KEY_SYSTEM);
185	st_le32(&cmd->phy_addr, rm->dma_buf_p +
186		offsetof(struct rackmeter_dma, mark));
187	st_le32(&cmd->cmd_dep, 0x02000000);
188	cmd++;
189
190	st_le16(&cmd->req_count, SAMPLE_COUNT * 4);
191	st_le16(&cmd->command, OUTPUT_MORE);
192	st_le32(&cmd->phy_addr, rm->dma_buf_p +
193		offsetof(struct rackmeter_dma, buf1));
194	cmd++;
195
196	st_le16(&cmd->req_count, 4);
197	st_le16(&cmd->command, STORE_WORD | INTR_ALWAYS | KEY_SYSTEM);
198	st_le32(&cmd->phy_addr, rm->dma_buf_p +
199		offsetof(struct rackmeter_dma, mark));
200	st_le32(&cmd->cmd_dep, 0x01000000);
201	cmd++;
202
203	st_le16(&cmd->req_count, SAMPLE_COUNT * 4);
204	st_le16(&cmd->command, OUTPUT_MORE | BR_ALWAYS);
205	st_le32(&cmd->phy_addr, rm->dma_buf_p +
206		offsetof(struct rackmeter_dma, buf2));
207	st_le32(&cmd->cmd_dep, rm->dma_buf_p);
208
209	rackmeter_do_pause(rm, 0);
210}
211
212static 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	cputime64_t cur_jiffies, total_idle_ticks;
219	unsigned int total_ticks, idle_ticks;
220	int i, offset, load, cumm, pause;
221
222	cur_jiffies = jiffies64_to_cputime64(get_jiffies_64());
223	total_ticks = (unsigned int)cputime64_sub(cur_jiffies,
224						  rcpu->prev_wall);
225	rcpu->prev_wall = cur_jiffies;
226
227	total_idle_ticks = get_cpu_idle_time(cpu);
228	idle_ticks = (unsigned int) cputime64_sub(total_idle_ticks,
229				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 __devinit 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 __devexit rackmeter_stop_cpu_sniffer(struct rackmeter *rm)
287{
288	cancel_rearming_delayed_work(&rm->cpu[0].sniffer);
289	cancel_rearming_delayed_work(&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
311static 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
323static 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
366static int __devinit 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	while ((i2s = of_get_next_child(mdev->ofdev.node, i2s)) != NULL)
378	       if (strcmp(i2s->name, "i2s-a") == 0)
379		       break;
380	if (i2s == NULL) {
381		pr_debug("  i2s-a child not found\n");
382		goto bail;
383	}
384	/* Get lightshow or virtual sound */
385	while ((np = of_get_next_child(i2s, np)) != NULL) {
386	       if (strcmp(np->name, "lightshow") == 0)
387		       break;
388	       if ((strcmp(np->name, "sound") == 0) &&
389		   of_get_property(np, "virtual", NULL) != NULL)
390		       break;
391	}
392	if (np == NULL) {
393		pr_debug("  lightshow or sound+virtual child not found\n");
394		goto bail;
395	}
396
397	/* Create and initialize our instance data */
398	rm = kzalloc(sizeof(struct rackmeter), GFP_KERNEL);
399	if (rm == NULL) {
400		printk(KERN_ERR "rackmeter: failed to allocate memory !\n");
401		rc = -ENOMEM;
402		goto bail_release;
403	}
404	rm->mdev = mdev;
405	rm->i2s = i2s;
406	mutex_init(&rm->sem);
407	dev_set_drvdata(&mdev->ofdev.dev, rm);
408	/* Check resources availability. We need at least resource 0 and 1 */
409	rm->irq = irq_of_parse_and_map(i2s, 1);
410	if (rm->irq == NO_IRQ ||
411	    of_address_to_resource(i2s, 0, &ri2s) ||
412	    of_address_to_resource(i2s, 1, &rdma)) {
413		printk(KERN_ERR
414		       "rackmeter: found match but lacks resources: %s",
415		       mdev->ofdev.node->full_name);
416		rc = -ENXIO;
417		goto bail_free;
418	}
419
420	pr_debug("  i2s @0x%08x\n", (unsigned int)ri2s.start);
421	pr_debug("  dma @0x%08x\n", (unsigned int)rdma.start);
422	pr_debug("  irq %d\n", rm->irq);
423
424	rm->ubuf = (u8 *)__get_free_page(GFP_KERNEL);
425	if (rm->ubuf == NULL) {
426		printk(KERN_ERR
427		       "rackmeter: failed to allocate samples page !\n");
428		rc = -ENOMEM;
429		goto bail_release;
430	}
431
432	rm->dma_buf_v = dma_alloc_coherent(&macio_get_pci_dev(mdev)->dev,
433					   sizeof(struct rackmeter_dma),
434					   &rm->dma_buf_p, GFP_KERNEL);
435	if (rm->dma_buf_v == NULL) {
436		printk(KERN_ERR
437		       "rackmeter: failed to allocate dma buffer !\n");
438		rc = -ENOMEM;
439		goto bail_free_samples;
440	}
441	rm->i2s_regs = ioremap(ri2s.start, 0x1000);
442	if (rm->i2s_regs == NULL) {
443		printk(KERN_ERR
444		       "rackmeter: failed to map i2s registers !\n");
445		rc = -ENXIO;
446		goto bail_free_dma;
447	}
448	rm->dma_regs = ioremap(rdma.start, 0x100);
449	if (rm->dma_regs == NULL) {
450		printk(KERN_ERR
451		       "rackmeter: failed to map dma registers !\n");
452		rc = -ENXIO;
453		goto bail_unmap_i2s;
454	}
455
456	rc = rackmeter_setup(rm);
457	if (rc) {
458		printk(KERN_ERR
459		       "rackmeter: failed to initialize !\n");
460		rc = -ENXIO;
461		goto bail_unmap_dma;
462	}
463
464	rc = request_irq(rm->irq, rackmeter_irq, 0, "rackmeter", rm);
465	if (rc != 0) {
466		printk(KERN_ERR
467		       "rackmeter: failed to request interrupt !\n");
468		goto bail_stop_dma;
469	}
470	of_node_put(np);
471	return 0;
472
473 bail_stop_dma:
474	DBDMA_DO_RESET(rm->dma_regs);
475 bail_unmap_dma:
476	iounmap(rm->dma_regs);
477 bail_unmap_i2s:
478	iounmap(rm->i2s_regs);
479 bail_free_dma:
480	dma_free_coherent(&macio_get_pci_dev(mdev)->dev,
481			  sizeof(struct rackmeter_dma),
482			  rm->dma_buf_v, rm->dma_buf_p);
483 bail_free_samples:
484	free_page((unsigned long)rm->ubuf);
485 bail_release:
486 bail_free:
487	kfree(rm);
488 bail:
489	of_node_put(i2s);
490	of_node_put(np);
491	dev_set_drvdata(&mdev->ofdev.dev, NULL);
492	return rc;
493}
494
495static int __devexit rackmeter_remove(struct macio_dev* mdev)
496{
497	struct rackmeter *rm = dev_get_drvdata(&mdev->ofdev.dev);
498
499	/* Stop CPU sniffer timer & work queues */
500	rackmeter_stop_cpu_sniffer(rm);
501
502	/* Clear reference to private data */
503	dev_set_drvdata(&mdev->ofdev.dev, NULL);
504
505	/* Stop/reset dbdma */
506	DBDMA_DO_RESET(rm->dma_regs);
507
508	/* Release the IRQ */
509	free_irq(rm->irq, rm);
510
511	/* Unmap registers */
512	iounmap(rm->dma_regs);
513	iounmap(rm->i2s_regs);
514
515	/* Free DMA */
516	dma_free_coherent(&macio_get_pci_dev(mdev)->dev,
517			  sizeof(struct rackmeter_dma),
518			  rm->dma_buf_v, rm->dma_buf_p);
519
520	/* Free samples */
521	free_page((unsigned long)rm->ubuf);
522
523
524	/* Get rid of me */
525	kfree(rm);
526
527	return 0;
528}
529
530static int rackmeter_shutdown(struct macio_dev* mdev)
531{
532	struct rackmeter *rm = dev_get_drvdata(&mdev->ofdev.dev);
533
534	if (rm == NULL)
535		return -ENODEV;
536
537	/* Stop CPU sniffer timer & work queues */
538	rackmeter_stop_cpu_sniffer(rm);
539
540	/* Stop/reset dbdma */
541	DBDMA_DO_RESET(rm->dma_regs);
542
543	return 0;
544}
545
546static struct of_device_id rackmeter_match[] = {
547	{ .name = "i2s" },
548	{ }
549};
550
551static struct macio_driver rackmeter_drv = {
552	.name = "rackmeter",
553	.owner = THIS_MODULE,
554	.match_table = rackmeter_match,
555	.probe = rackmeter_probe,
556	.remove = rackmeter_remove,
557	.shutdown = rackmeter_shutdown,
558};
559
560
561static int __init rackmeter_init(void)
562{
563	pr_debug("rackmeter_init()\n");
564
565	return macio_register_driver(&rackmeter_drv);
566}
567
568static void __exit rackmeter_exit(void)
569{
570	pr_debug("rackmeter_exit()\n");
571
572	macio_unregister_driver(&rackmeter_drv);
573}
574
575module_init(rackmeter_init);
576module_exit(rackmeter_exit);
577
578
579MODULE_LICENSE("GPL");
580MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
581MODULE_DESCRIPTION("RackMeter: Support vu-meter on XServe front panel");
582