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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 u64 prev_wall;
56 u64 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 u64 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, sizeof(rdma->buf1));
158 memset(rdma->buf2, 0, sizeof(rdma->buf2));
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 cmd->req_count = cpu_to_le16(4);
186 cmd->command = cpu_to_le16(STORE_WORD | INTR_ALWAYS | KEY_SYSTEM);
187 cmd->phy_addr = cpu_to_le32(rm->dma_buf_p +
188 offsetof(struct rackmeter_dma, mark));
189 cmd->cmd_dep = cpu_to_le32(0x02000000);
190 cmd++;
191
192 cmd->req_count = cpu_to_le16(SAMPLE_COUNT * 4);
193 cmd->command = cpu_to_le16(OUTPUT_MORE);
194 cmd->phy_addr = cpu_to_le32(rm->dma_buf_p +
195 offsetof(struct rackmeter_dma, buf1));
196 cmd++;
197
198 cmd->req_count = cpu_to_le16(4);
199 cmd->command = cpu_to_le16(STORE_WORD | INTR_ALWAYS | KEY_SYSTEM);
200 cmd->phy_addr = cpu_to_le32(rm->dma_buf_p +
201 offsetof(struct rackmeter_dma, mark));
202 cmd->cmd_dep = cpu_to_le32(0x01000000);
203 cmd++;
204
205 cmd->req_count = cpu_to_le16(SAMPLE_COUNT * 4);
206 cmd->command = cpu_to_le16(OUTPUT_MORE | BR_ALWAYS);
207 cmd->phy_addr = cpu_to_le32(rm->dma_buf_p +
208 offsetof(struct rackmeter_dma, buf2));
209 cmd->cmd_dep = cpu_to_le32(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 u64 cur_nsecs, total_idle_nsecs;
221 u64 total_nsecs, idle_nsecs;
222 int i, offset, load, cumm, pause;
223
224 cur_nsecs = jiffies64_to_nsecs(get_jiffies_64());
225 total_nsecs = cur_nsecs - rcpu->prev_wall;
226 rcpu->prev_wall = cur_nsecs;
227
228 total_idle_nsecs = get_cpu_idle_time(cpu);
229 idle_nsecs = total_idle_nsecs - rcpu->prev_idle;
230 idle_nsecs = min(idle_nsecs, total_nsecs);
231 rcpu->prev_idle = total_idle_nsecs;
232
233 /* We do a very dumb calculation to update the LEDs for now,
234 * we'll do better once we have actual PWM implemented
235 */
236 load = div64_u64(9 * (total_nsecs - idle_nsecs), total_nsecs);
237
238 offset = cpu << 3;
239 cumm = 0;
240 for (i = 0; i < 8; i++) {
241 u8 ub = (load > i) ? 0xff : 0;
242 rm->ubuf[i + offset] = ub;
243 cumm |= ub;
244 }
245 rcpu->zero = (cumm == 0);
246
247 /* Now check if LEDs are all 0, we can stop DMA */
248 pause = (rm->cpu[0].zero && rm->cpu[1].zero);
249 if (pause != rm->paused) {
250 mutex_lock(&rm->sem);
251 pause = (rm->cpu[0].zero && rm->cpu[1].zero);
252 rackmeter_do_pause(rm, pause);
253 mutex_unlock(&rm->sem);
254 }
255 schedule_delayed_work_on(cpu, &rcpu->sniffer,
256 msecs_to_jiffies(CPU_SAMPLING_RATE));
257}
258
259static void rackmeter_init_cpu_sniffer(struct rackmeter *rm)
260{
261 unsigned int cpu;
262
263 /* This driver works only with 1 or 2 CPUs numbered 0 and 1,
264 * but that's really all we have on Apple Xserve. It doesn't
265 * play very nice with CPU hotplug neither but we don't do that
266 * on those machines yet
267 */
268
269 rm->cpu[0].rm = rm;
270 INIT_DELAYED_WORK(&rm->cpu[0].sniffer, rackmeter_do_timer);
271 rm->cpu[1].rm = rm;
272 INIT_DELAYED_WORK(&rm->cpu[1].sniffer, rackmeter_do_timer);
273
274 for_each_online_cpu(cpu) {
275 struct rackmeter_cpu *rcpu;
276
277 if (cpu > 1)
278 continue;
279 rcpu = &rm->cpu[cpu];
280 rcpu->prev_idle = get_cpu_idle_time(cpu);
281 rcpu->prev_wall = jiffies64_to_nsecs(get_jiffies_64());
282 schedule_delayed_work_on(cpu, &rm->cpu[cpu].sniffer,
283 msecs_to_jiffies(CPU_SAMPLING_RATE));
284 }
285}
286
287static void rackmeter_stop_cpu_sniffer(struct rackmeter *rm)
288{
289 cancel_delayed_work_sync(&rm->cpu[0].sniffer);
290 cancel_delayed_work_sync(&rm->cpu[1].sniffer);
291}
292
293static int rackmeter_setup(struct rackmeter *rm)
294{
295 pr_debug("rackmeter: setting up i2s..\n");
296 rackmeter_setup_i2s(rm);
297
298 pr_debug("rackmeter: setting up default pattern..\n");
299 rackmeter_set_default_pattern(rm);
300
301 pr_debug("rackmeter: setting up dbdma..\n");
302 rackmeter_setup_dbdma(rm);
303
304 pr_debug("rackmeter: start CPU measurements..\n");
305 rackmeter_init_cpu_sniffer(rm);
306
307 printk(KERN_INFO "RackMeter initialized\n");
308
309 return 0;
310}
311
312/* XXX FIXME: No PWM yet, this is 0/1 */
313static u32 rackmeter_calc_sample(struct rackmeter *rm, unsigned int index)
314{
315 int led;
316 u32 sample = 0;
317
318 for (led = 0; led < 16; led++) {
319 sample >>= 1;
320 sample |= ((rm->ubuf[led] >= 0x80) << 15);
321 }
322 return (sample << 17) | (sample >> 15);
323}
324
325static irqreturn_t rackmeter_irq(int irq, void *arg)
326{
327 struct rackmeter *rm = arg;
328 struct rackmeter_dma *db = rm->dma_buf_v;
329 unsigned int mark, i;
330 u32 *buf;
331
332 /* Flush PCI buffers with an MMIO read. Maybe we could actually
333 * check the status one day ... in case things go wrong, though
334 * this never happened to me
335 */
336 (void)in_le32(&rm->dma_regs->status);
337
338 /* Make sure the CPU gets us in order */
339 rmb();
340
341 /* Read mark */
342 mark = db->mark;
343 if (mark != 1 && mark != 2) {
344 printk(KERN_WARNING "rackmeter: Incorrect DMA mark 0x%08x\n",
345 mark);
346 /* We allow for 3 errors like that (stale DBDMA irqs) */
347 if (++rm->stale_irq > 3) {
348 printk(KERN_ERR "rackmeter: Too many errors,"
349 " stopping DMA\n");
350 DBDMA_DO_RESET(rm->dma_regs);
351 }
352 return IRQ_HANDLED;
353 }
354
355 /* Next buffer we need to fill is mark value */
356 buf = mark == 1 ? db->buf1 : db->buf2;
357
358 /* Fill it now. This routine converts the 8 bits depth sample array
359 * into the PWM bitmap for each LED.
360 */
361 for (i = 0; i < SAMPLE_COUNT; i++)
362 buf[i] = rackmeter_calc_sample(rm, i);
363
364
365 return IRQ_HANDLED;
366}
367
368static int rackmeter_probe(struct macio_dev* mdev,
369 const struct of_device_id *match)
370{
371 struct device_node *i2s = NULL, *np = NULL;
372 struct rackmeter *rm = NULL;
373 struct resource ri2s, rdma;
374 int rc = -ENODEV;
375
376 pr_debug("rackmeter_probe()\n");
377
378 /* Get i2s-a node */
379 for_each_child_of_node(mdev->ofdev.dev.of_node, i2s)
380 if (of_node_name_eq(i2s, "i2s-a"))
381 break;
382
383 if (i2s == NULL) {
384 pr_debug(" i2s-a child not found\n");
385 goto bail;
386 }
387 /* Get lightshow or virtual sound */
388 for_each_child_of_node(i2s, np) {
389 if (of_node_name_eq(np, "lightshow"))
390 break;
391 if (of_node_name_eq(np, "sound") &&
392 of_get_property(np, "virtual", NULL) != NULL)
393 break;
394 }
395 if (np == NULL) {
396 pr_debug(" lightshow or sound+virtual child not found\n");
397 goto bail;
398 }
399
400 /* Create and initialize our instance data */
401 rm = kzalloc(sizeof(*rm), GFP_KERNEL);
402 if (rm == NULL) {
403 printk(KERN_ERR "rackmeter: failed to allocate memory !\n");
404 rc = -ENOMEM;
405 goto bail_release;
406 }
407 rm->mdev = mdev;
408 rm->i2s = i2s;
409 mutex_init(&rm->sem);
410 dev_set_drvdata(&mdev->ofdev.dev, rm);
411 /* Check resources availability. We need at least resource 0 and 1 */
412#if 0 /* Use that when i2s-a is finally an mdev per-se */
413 if (macio_resource_count(mdev) < 2 || macio_irq_count(mdev) < 2) {
414 printk(KERN_ERR
415 "rackmeter: found match but lacks resources: %pOF"
416 " (%d resources, %d interrupts)\n",
417 mdev->ofdev.dev.of_node);
418 rc = -ENXIO;
419 goto bail_free;
420 }
421 if (macio_request_resources(mdev, "rackmeter")) {
422 printk(KERN_ERR
423 "rackmeter: failed to request resources: %pOF\n",
424 mdev->ofdev.dev.of_node);
425 rc = -EBUSY;
426 goto bail_free;
427 }
428 rm->irq = macio_irq(mdev, 1);
429#else
430 rm->irq = irq_of_parse_and_map(i2s, 1);
431 if (!rm->irq ||
432 of_address_to_resource(i2s, 0, &ri2s) ||
433 of_address_to_resource(i2s, 1, &rdma)) {
434 printk(KERN_ERR
435 "rackmeter: found match but lacks resources: %pOF",
436 mdev->ofdev.dev.of_node);
437 rc = -ENXIO;
438 goto bail_free;
439 }
440#endif
441
442 pr_debug(" i2s @0x%08x\n", (unsigned int)ri2s.start);
443 pr_debug(" dma @0x%08x\n", (unsigned int)rdma.start);
444 pr_debug(" irq %d\n", rm->irq);
445
446 rm->ubuf = (u8 *)__get_free_page(GFP_KERNEL);
447 if (rm->ubuf == NULL) {
448 printk(KERN_ERR
449 "rackmeter: failed to allocate samples page !\n");
450 rc = -ENOMEM;
451 goto bail_release;
452 }
453
454 rm->dma_buf_v = dma_alloc_coherent(&macio_get_pci_dev(mdev)->dev,
455 sizeof(struct rackmeter_dma),
456 &rm->dma_buf_p, GFP_KERNEL);
457 if (rm->dma_buf_v == NULL) {
458 printk(KERN_ERR
459 "rackmeter: failed to allocate dma buffer !\n");
460 rc = -ENOMEM;
461 goto bail_free_samples;
462 }
463#if 0
464 rm->i2s_regs = ioremap(macio_resource_start(mdev, 0), 0x1000);
465#else
466 rm->i2s_regs = ioremap(ri2s.start, 0x1000);
467#endif
468 if (rm->i2s_regs == NULL) {
469 printk(KERN_ERR
470 "rackmeter: failed to map i2s registers !\n");
471 rc = -ENXIO;
472 goto bail_free_dma;
473 }
474#if 0
475 rm->dma_regs = ioremap(macio_resource_start(mdev, 1), 0x100);
476#else
477 rm->dma_regs = ioremap(rdma.start, 0x100);
478#endif
479 if (rm->dma_regs == NULL) {
480 printk(KERN_ERR
481 "rackmeter: failed to map dma registers !\n");
482 rc = -ENXIO;
483 goto bail_unmap_i2s;
484 }
485
486 rc = rackmeter_setup(rm);
487 if (rc) {
488 printk(KERN_ERR
489 "rackmeter: failed to initialize !\n");
490 rc = -ENXIO;
491 goto bail_unmap_dma;
492 }
493
494 rc = request_irq(rm->irq, rackmeter_irq, 0, "rackmeter", rm);
495 if (rc != 0) {
496 printk(KERN_ERR
497 "rackmeter: failed to request interrupt !\n");
498 goto bail_stop_dma;
499 }
500 of_node_put(np);
501 return 0;
502
503 bail_stop_dma:
504 DBDMA_DO_RESET(rm->dma_regs);
505 bail_unmap_dma:
506 iounmap(rm->dma_regs);
507 bail_unmap_i2s:
508 iounmap(rm->i2s_regs);
509 bail_free_dma:
510 dma_free_coherent(&macio_get_pci_dev(mdev)->dev,
511 sizeof(struct rackmeter_dma),
512 rm->dma_buf_v, rm->dma_buf_p);
513 bail_free_samples:
514 free_page((unsigned long)rm->ubuf);
515 bail_release:
516#if 0
517 macio_release_resources(mdev);
518#endif
519 bail_free:
520 kfree(rm);
521 bail:
522 of_node_put(i2s);
523 of_node_put(np);
524 dev_set_drvdata(&mdev->ofdev.dev, NULL);
525 return rc;
526}
527
528static int rackmeter_remove(struct macio_dev* mdev)
529{
530 struct rackmeter *rm = dev_get_drvdata(&mdev->ofdev.dev);
531
532 /* Stop CPU sniffer timer & work queues */
533 rackmeter_stop_cpu_sniffer(rm);
534
535 /* Clear reference to private data */
536 dev_set_drvdata(&mdev->ofdev.dev, NULL);
537
538 /* Stop/reset dbdma */
539 DBDMA_DO_RESET(rm->dma_regs);
540
541 /* Release the IRQ */
542 free_irq(rm->irq, rm);
543
544 /* Unmap registers */
545 iounmap(rm->dma_regs);
546 iounmap(rm->i2s_regs);
547
548 /* Free DMA */
549 dma_free_coherent(&macio_get_pci_dev(mdev)->dev,
550 sizeof(struct rackmeter_dma),
551 rm->dma_buf_v, rm->dma_buf_p);
552
553 /* Free samples */
554 free_page((unsigned long)rm->ubuf);
555
556#if 0
557 /* Release resources */
558 macio_release_resources(mdev);
559#endif
560
561 /* Get rid of me */
562 kfree(rm);
563
564 return 0;
565}
566
567static int rackmeter_shutdown(struct macio_dev* mdev)
568{
569 struct rackmeter *rm = dev_get_drvdata(&mdev->ofdev.dev);
570
571 if (rm == NULL)
572 return -ENODEV;
573
574 /* Stop CPU sniffer timer & work queues */
575 rackmeter_stop_cpu_sniffer(rm);
576
577 /* Stop/reset dbdma */
578 DBDMA_DO_RESET(rm->dma_regs);
579
580 return 0;
581}
582
583static const struct of_device_id rackmeter_match[] = {
584 { .name = "i2s" },
585 { }
586};
587MODULE_DEVICE_TABLE(of, rackmeter_match);
588
589static struct macio_driver rackmeter_driver = {
590 .driver = {
591 .name = "rackmeter",
592 .owner = THIS_MODULE,
593 .of_match_table = rackmeter_match,
594 },
595 .probe = rackmeter_probe,
596 .remove = rackmeter_remove,
597 .shutdown = rackmeter_shutdown,
598};
599
600
601static int __init rackmeter_init(void)
602{
603 pr_debug("rackmeter_init()\n");
604
605 return macio_register_driver(&rackmeter_driver);
606}
607
608static void __exit rackmeter_exit(void)
609{
610 pr_debug("rackmeter_exit()\n");
611
612 macio_unregister_driver(&rackmeter_driver);
613}
614
615module_init(rackmeter_init);
616module_exit(rackmeter_exit);
617
618
619MODULE_LICENSE("GPL");
620MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
621MODULE_DESCRIPTION("RackMeter: Support vu-meter on XServe front panel");
622

Warning: That file was not part of the compilation database. It may have many parsing errors.