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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * RackMac vu-meter driver
4 *
5 * (c) Copyright 2006 Benjamin Herrenschmidt, IBM Corp.
6 * <[email protected]>
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
42struct 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
49struct 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
57struct 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 */
73static 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 */
81static 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(CPUTIME_NICE, cpu);
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, 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
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 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
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 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
257static 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
285static 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
291static 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 */
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 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_obj(*rm);
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
526static void 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
563static int rackmeter_shutdown(struct macio_dev* mdev)
564{
565 struct rackmeter *rm = dev_get_drvdata(&mdev->ofdev.dev);
566
567 if (rm == NULL)
568 return -ENODEV;
569
570 /* Stop CPU sniffer timer & work queues */
571 rackmeter_stop_cpu_sniffer(rm);
572
573 /* Stop/reset dbdma */
574 DBDMA_DO_RESET(rm->dma_regs);
575
576 return 0;
577}
578
579static const struct of_device_id rackmeter_match[] = {
580 { .name = "i2s" },
581 { }
582};
583MODULE_DEVICE_TABLE(of, rackmeter_match);
584
585static struct macio_driver rackmeter_driver = {
586 .driver = {
587 .name = "rackmeter",
588 .owner = THIS_MODULE,
589 .of_match_table = rackmeter_match,
590 },
591 .probe = rackmeter_probe,
592 .remove = rackmeter_remove,
593 .shutdown = rackmeter_shutdown,
594};
595
596
597static int __init rackmeter_init(void)
598{
599 pr_debug("rackmeter_init()\n");
600
601 return macio_register_driver(&rackmeter_driver);
602}
603
604static void __exit rackmeter_exit(void)
605{
606 pr_debug("rackmeter_exit()\n");
607
608 macio_unregister_driver(&rackmeter_driver);
609}
610
611module_init(rackmeter_init);
612module_exit(rackmeter_exit);
613
614
615MODULE_LICENSE("GPL");
616MODULE_AUTHOR("Benjamin Herrenschmidt <[email protected]>");
617MODULE_DESCRIPTION("RackMeter: Support vu-meter on XServe front panel");