2 * RackMac vu-meter driver
4 * (c) Copyright 2006 Benjamin Herrenschmidt, IBM Corp.
5 * <benh@kernel.crashing.org>
7 * Released under the term of the GNU GPL v2.
9 * Support the CPU-meter LEDs of the Xserve G5
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 :-)
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>
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>
37 /* Number of samples in a sample buffer */
38 #define SAMPLE_COUNT 256
40 /* CPU meter sampling rate in ms */
41 #define CPU_SAMPLING_RATE 250
43 struct 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;
50 struct rackmeter_cpu {
51 struct delayed_work sniffer;
53 cputime64_t prev_wall;
54 cputime64_t prev_idle;
56 } ____cacheline_aligned;
59 struct macio_dev *mdev;
61 struct device_node *i2s;
63 struct dbdma_regs __iomem *dma_regs;
64 void __iomem *i2s_regs;
66 struct rackmeter_dma *dma_buf_v;
68 struct rackmeter_cpu cpu[2];
73 /* To be set as a tunable */
74 static int rackmeter_ignore_nice;
76 /* This GPIO is whacked by the OS X driver when initializing */
77 #define RACKMETER_MAGIC_GPIO 0x78
79 /* This is copied from cpufreq_ondemand, maybe we should put it in
80 * a common header somewhere
82 static inline cputime64_t get_cpu_idle_time(unsigned int cpu)
86 retval = cputime64_add(kstat_cpu(cpu).cpustat.idle,
87 kstat_cpu(cpu).cpustat.iowait);
89 if (rackmeter_ignore_nice)
90 retval = cputime64_add(retval, kstat_cpu(cpu).cpustat.nice);
95 static void rackmeter_setup_i2s(struct rackmeter *rm)
97 struct macio_chip *macio = rm->mdev->bus->chip;
99 /* First whack magic GPIO */
100 pmac_call_feature(PMAC_FTR_WRITE_GPIO, NULL, RACKMETER_MAGIC_GPIO, 5);
103 /* Call feature code to enable the sound channel and the proper
106 pmac_call_feature(PMAC_FTR_SOUND_CHIP_ENABLE, rm->i2s, 0, 1);
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
112 MACIO_BIS(KEYLARGO_FCR1, KL1_I2S0_ENABLE);
113 MACIO_BIC(KEYLARGO_FCR1, KL1_I2S0_CLK_ENABLE_BIT);
114 (void)MACIO_IN32(KEYLARGO_FCR1);
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
121 out_le32(rm->i2s_regs + 0x10, 0x01fa0000);
122 (void)in_le32(rm->i2s_regs + 0x10);
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);
132 static void rackmeter_set_default_pattern(struct rackmeter *rm)
136 for (i = 0; i < 16; i++) {
138 rm->ubuf[i] = (i & 1) * 255;
140 rm->ubuf[i] = ((~i) & 1) * 255;
144 static void rackmeter_do_pause(struct rackmeter *rm, int pause)
146 struct rackmeter_dma *rdma = rm->dma_buf_v;
148 pr_debug("rackmeter: %s\n", pause ? "paused" : "started");
152 DBDMA_DO_STOP(rm->dma_regs);
155 memset(rdma->buf1, 0, SAMPLE_COUNT & sizeof(u32));
156 memset(rdma->buf2, 0, SAMPLE_COUNT & sizeof(u32));
158 rm->dma_buf_v->mark = 0;
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);
166 static void rackmeter_setup_dbdma(struct rackmeter *rm)
168 struct rackmeter_dma *db = rm->dma_buf_v;
169 struct dbdma_cmd *cmd = db->cmd;
171 /* Make sure dbdma is reset */
172 DBDMA_DO_RESET(rm->dma_regs);
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));
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);
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));
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);
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);
209 rackmeter_do_pause(rm, 0);
212 static void rackmeter_do_timer(struct work_struct *work)
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;
222 cur_jiffies = jiffies64_to_cputime64(get_jiffies_64());
223 total_ticks = (unsigned int)cputime64_sub(cur_jiffies,
225 rcpu->prev_wall = cur_jiffies;
227 total_idle_ticks = get_cpu_idle_time(cpu);
228 idle_ticks = (unsigned int) cputime64_sub(total_idle_ticks,
230 rcpu->prev_idle = total_idle_ticks;
232 /* We do a very dumb calculation to update the LEDs for now,
233 * we'll do better once we have actual PWM implemented
235 load = (9 * (total_ticks - idle_ticks)) / total_ticks;
239 for (i = 0; i < 8; i++) {
240 u8 ub = (load > i) ? 0xff : 0;
241 rm->ubuf[i + offset] = ub;
244 rcpu->zero = (cumm == 0);
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);
254 schedule_delayed_work_on(cpu, &rcpu->sniffer,
255 msecs_to_jiffies(CPU_SAMPLING_RATE));
258 static void __devinit rackmeter_init_cpu_sniffer(struct rackmeter *rm)
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
269 INIT_DELAYED_WORK(&rm->cpu[0].sniffer, rackmeter_do_timer);
271 INIT_DELAYED_WORK(&rm->cpu[1].sniffer, rackmeter_do_timer);
273 for_each_online_cpu(cpu) {
274 struct rackmeter_cpu *rcpu;
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));
286 static void rackmeter_stop_cpu_sniffer(struct rackmeter *rm)
288 cancel_delayed_work_sync(&rm->cpu[0].sniffer);
289 cancel_delayed_work_sync(&rm->cpu[1].sniffer);
292 static int __devinit rackmeter_setup(struct rackmeter *rm)
294 pr_debug("rackmeter: setting up i2s..\n");
295 rackmeter_setup_i2s(rm);
297 pr_debug("rackmeter: setting up default pattern..\n");
298 rackmeter_set_default_pattern(rm);
300 pr_debug("rackmeter: setting up dbdma..\n");
301 rackmeter_setup_dbdma(rm);
303 pr_debug("rackmeter: start CPU measurements..\n");
304 rackmeter_init_cpu_sniffer(rm);
306 printk(KERN_INFO "RackMeter initialized\n");
311 /* XXX FIXME: No PWM yet, this is 0/1 */
312 static u32 rackmeter_calc_sample(struct rackmeter *rm, unsigned int index)
317 for (led = 0; led < 16; led++) {
319 sample |= ((rm->ubuf[led] >= 0x80) << 15);
321 return (sample << 17) | (sample >> 15);
324 static irqreturn_t rackmeter_irq(int irq, void *arg)
326 struct rackmeter *rm = arg;
327 struct rackmeter_dma *db = rm->dma_buf_v;
328 unsigned int mark, i;
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
335 (void)in_le32(&rm->dma_regs->status);
337 /* Make sure the CPU gets us in order */
342 if (mark != 1 && mark != 2) {
343 printk(KERN_WARNING "rackmeter: Incorrect DMA mark 0x%08x\n",
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,"
349 DBDMA_DO_RESET(rm->dma_regs);
354 /* Next buffer we need to fill is mark value */
355 buf = mark == 1 ? db->buf1 : db->buf2;
357 /* Fill it now. This routine converts the 8 bits depth sample array
358 * into the PWM bitmap for each LED.
360 for (i = 0; i < SAMPLE_COUNT; i++)
361 buf[i] = rackmeter_calc_sample(rm, i);
367 static int __devinit rackmeter_probe(struct macio_dev* mdev,
368 const struct of_device_id *match)
370 struct device_node *i2s = NULL, *np = NULL;
371 struct rackmeter *rm = NULL;
372 struct resource ri2s, rdma;
375 pr_debug("rackmeter_probe()\n");
378 while ((i2s = of_get_next_child(mdev->ofdev.dev.of_node, i2s)) != NULL)
379 if (strcmp(i2s->name, "i2s-a") == 0)
382 pr_debug(" i2s-a child not found\n");
385 /* Get lightshow or virtual sound */
386 while ((np = of_get_next_child(i2s, np)) != NULL) {
387 if (strcmp(np->name, "lightshow") == 0)
389 if ((strcmp(np->name, "sound") == 0) &&
390 of_get_property(np, "virtual", NULL) != NULL)
394 pr_debug(" lightshow or sound+virtual child not found\n");
398 /* Create and initialize our instance data */
399 rm = kzalloc(sizeof(struct rackmeter), GFP_KERNEL);
401 printk(KERN_ERR "rackmeter: failed to allocate memory !\n");
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) {
413 "rackmeter: found match but lacks resources: %s"
414 " (%d resources, %d interrupts)\n",
415 mdev->ofdev.node->full_name);
419 if (macio_request_resources(mdev, "rackmeter")) {
421 "rackmeter: failed to request resources: %s\n",
422 mdev->ofdev.node->full_name);
426 rm->irq = macio_irq(mdev, 1);
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)) {
433 "rackmeter: found match but lacks resources: %s",
434 mdev->ofdev.dev.of_node->full_name);
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);
444 rm->ubuf = (u8 *)__get_free_page(GFP_KERNEL);
445 if (rm->ubuf == NULL) {
447 "rackmeter: failed to allocate samples page !\n");
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) {
457 "rackmeter: failed to allocate dma buffer !\n");
459 goto bail_free_samples;
462 rm->i2s_regs = ioremap(macio_resource_start(mdev, 0), 0x1000);
464 rm->i2s_regs = ioremap(ri2s.start, 0x1000);
466 if (rm->i2s_regs == NULL) {
468 "rackmeter: failed to map i2s registers !\n");
473 rm->dma_regs = ioremap(macio_resource_start(mdev, 1), 0x100);
475 rm->dma_regs = ioremap(rdma.start, 0x100);
477 if (rm->dma_regs == NULL) {
479 "rackmeter: failed to map dma registers !\n");
484 rc = rackmeter_setup(rm);
487 "rackmeter: failed to initialize !\n");
492 rc = request_irq(rm->irq, rackmeter_irq, 0, "rackmeter", rm);
495 "rackmeter: failed to request interrupt !\n");
502 DBDMA_DO_RESET(rm->dma_regs);
504 iounmap(rm->dma_regs);
506 iounmap(rm->i2s_regs);
508 dma_free_coherent(&macio_get_pci_dev(mdev)->dev,
509 sizeof(struct rackmeter_dma),
510 rm->dma_buf_v, rm->dma_buf_p);
512 free_page((unsigned long)rm->ubuf);
515 macio_release_resources(mdev);
522 dev_set_drvdata(&mdev->ofdev.dev, NULL);
526 static int __devexit rackmeter_remove(struct macio_dev* mdev)
528 struct rackmeter *rm = dev_get_drvdata(&mdev->ofdev.dev);
530 /* Stop CPU sniffer timer & work queues */
531 rackmeter_stop_cpu_sniffer(rm);
533 /* Clear reference to private data */
534 dev_set_drvdata(&mdev->ofdev.dev, NULL);
536 /* Stop/reset dbdma */
537 DBDMA_DO_RESET(rm->dma_regs);
539 /* Release the IRQ */
540 free_irq(rm->irq, rm);
542 /* Unmap registers */
543 iounmap(rm->dma_regs);
544 iounmap(rm->i2s_regs);
547 dma_free_coherent(&macio_get_pci_dev(mdev)->dev,
548 sizeof(struct rackmeter_dma),
549 rm->dma_buf_v, rm->dma_buf_p);
552 free_page((unsigned long)rm->ubuf);
555 /* Release resources */
556 macio_release_resources(mdev);
565 static int rackmeter_shutdown(struct macio_dev* mdev)
567 struct rackmeter *rm = dev_get_drvdata(&mdev->ofdev.dev);
572 /* Stop CPU sniffer timer & work queues */
573 rackmeter_stop_cpu_sniffer(rm);
575 /* Stop/reset dbdma */
576 DBDMA_DO_RESET(rm->dma_regs);
581 static struct of_device_id rackmeter_match[] = {
586 static struct macio_driver rackmeter_driver = {
589 .owner = THIS_MODULE,
590 .of_match_table = rackmeter_match,
592 .probe = rackmeter_probe,
593 .remove = __devexit_p(rackmeter_remove),
594 .shutdown = rackmeter_shutdown,
598 static int __init rackmeter_init(void)
600 pr_debug("rackmeter_init()\n");
602 return macio_register_driver(&rackmeter_driver);
605 static void __exit rackmeter_exit(void)
607 pr_debug("rackmeter_exit()\n");
609 macio_unregister_driver(&rackmeter_driver);
612 module_init(rackmeter_init);
613 module_exit(rackmeter_exit);
616 MODULE_LICENSE("GPL");
617 MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
618 MODULE_DESCRIPTION("RackMeter: Support vu-meter on XServe front panel");