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/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>
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>
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 work_struct sniffer;
52 cputime64_t prev_wall;
53 cputime64_t prev_idle;
55 } ____cacheline_aligned;
58 struct macio_dev *mdev;
60 struct device_node *i2s;
62 struct dbdma_regs __iomem *dma_regs;
63 void __iomem *i2s_regs;
65 struct rackmeter_dma *dma_buf_v;
67 struct rackmeter_cpu cpu[2];
72 /* To be set as a tunable */
73 static int rackmeter_ignore_nice;
75 /* This GPIO is whacked by the OS X driver when initializing */
76 #define RACKMETER_MAGIC_GPIO 0x78
78 /* This is copied from cpufreq_ondemand, maybe we should put it in
79 * a common header somewhere
81 static inline cputime64_t get_cpu_idle_time(unsigned int cpu)
85 retval = cputime64_add(kstat_cpu(cpu).cpustat.idle,
86 kstat_cpu(cpu).cpustat.iowait);
88 if (rackmeter_ignore_nice)
89 retval = cputime64_add(retval, kstat_cpu(cpu).cpustat.nice);
94 static void rackmeter_setup_i2s(struct rackmeter *rm)
96 struct macio_chip *macio = rm->mdev->bus->chip;
98 /* First whack magic GPIO */
99 pmac_call_feature(PMAC_FTR_WRITE_GPIO, NULL, RACKMETER_MAGIC_GPIO, 5);
102 /* Call feature code to enable the sound channel and the proper
105 pmac_call_feature(PMAC_FTR_SOUND_CHIP_ENABLE, rm->i2s, 0, 1);
107 /* Power i2s and stop i2s clock. We whack MacIO FCRs directly for now.
108 * This is a bit racy, thus we should add new platform functions to
109 * handle that. snd-aoa needs that too
111 MACIO_BIS(KEYLARGO_FCR1, KL1_I2S0_ENABLE);
112 MACIO_BIC(KEYLARGO_FCR1, KL1_I2S0_CLK_ENABLE_BIT);
113 (void)MACIO_IN32(KEYLARGO_FCR1);
116 /* Then setup i2s. For now, we use the same magic value that
117 * the OS X driver seems to use. We might want to play around
118 * with the clock divisors later
120 out_le32(rm->i2s_regs + 0x10, 0x01fa0000);
121 (void)in_le32(rm->i2s_regs + 0x10);
124 /* Fully restart i2s*/
125 MACIO_BIS(KEYLARGO_FCR1, KL1_I2S0_CELL_ENABLE |
126 KL1_I2S0_CLK_ENABLE_BIT);
127 (void)MACIO_IN32(KEYLARGO_FCR1);
131 static void rackmeter_set_default_pattern(struct rackmeter *rm)
135 for (i = 0; i < 16; i++) {
137 rm->ubuf[i] = (i & 1) * 255;
139 rm->ubuf[i] = ((~i) & 1) * 255;
143 static void rackmeter_do_pause(struct rackmeter *rm, int pause)
145 struct rackmeter_dma *rdma = rm->dma_buf_v;
147 pr_debug("rackmeter: %s\n", pause ? "paused" : "started");
151 DBDMA_DO_STOP(rm->dma_regs);
154 memset(rdma->buf1, 0, SAMPLE_COUNT & sizeof(u32));
155 memset(rdma->buf2, 0, SAMPLE_COUNT & sizeof(u32));
157 rm->dma_buf_v->mark = 0;
160 out_le32(&rm->dma_regs->cmdptr_hi, 0);
161 out_le32(&rm->dma_regs->cmdptr, rm->dma_buf_p);
162 out_le32(&rm->dma_regs->control, (RUN << 16) | RUN);
165 static void rackmeter_setup_dbdma(struct rackmeter *rm)
167 struct rackmeter_dma *db = rm->dma_buf_v;
168 struct dbdma_cmd *cmd = db->cmd;
170 /* Make sure dbdma is reset */
171 DBDMA_DO_RESET(rm->dma_regs);
173 pr_debug("rackmeter: mark offset=0x%lx\n",
174 offsetof(struct rackmeter_dma, mark));
175 pr_debug("rackmeter: buf1 offset=0x%lx\n",
176 offsetof(struct rackmeter_dma, buf1));
177 pr_debug("rackmeter: buf2 offset=0x%lx\n",
178 offsetof(struct rackmeter_dma, buf2));
180 /* Prepare 4 dbdma commands for the 2 buffers */
181 memset(cmd, 0, 4 * sizeof(struct dbdma_cmd));
182 st_le16(&cmd->req_count, 4);
183 st_le16(&cmd->command, STORE_WORD | INTR_ALWAYS | KEY_SYSTEM);
184 st_le32(&cmd->phy_addr, rm->dma_buf_p +
185 offsetof(struct rackmeter_dma, mark));
186 st_le32(&cmd->cmd_dep, 0x02000000);
189 st_le16(&cmd->req_count, SAMPLE_COUNT * 4);
190 st_le16(&cmd->command, OUTPUT_MORE);
191 st_le32(&cmd->phy_addr, rm->dma_buf_p +
192 offsetof(struct rackmeter_dma, buf1));
195 st_le16(&cmd->req_count, 4);
196 st_le16(&cmd->command, STORE_WORD | INTR_ALWAYS | KEY_SYSTEM);
197 st_le32(&cmd->phy_addr, rm->dma_buf_p +
198 offsetof(struct rackmeter_dma, mark));
199 st_le32(&cmd->cmd_dep, 0x01000000);
202 st_le16(&cmd->req_count, SAMPLE_COUNT * 4);
203 st_le16(&cmd->command, OUTPUT_MORE | BR_ALWAYS);
204 st_le32(&cmd->phy_addr, rm->dma_buf_p +
205 offsetof(struct rackmeter_dma, buf2));
206 st_le32(&cmd->cmd_dep, rm->dma_buf_p);
208 rackmeter_do_pause(rm, 0);
211 static void rackmeter_do_timer(void *data)
213 struct rackmeter *rm = data;
214 unsigned int cpu = smp_processor_id();
215 struct rackmeter_cpu *rcpu = &rm->cpu[cpu];
216 cputime64_t cur_jiffies, total_idle_ticks;
217 unsigned int total_ticks, idle_ticks;
218 int i, offset, load, cumm, pause;
220 cur_jiffies = jiffies64_to_cputime64(get_jiffies_64());
221 total_ticks = (unsigned int)cputime64_sub(cur_jiffies,
223 rcpu->prev_wall = cur_jiffies;
225 total_idle_ticks = get_cpu_idle_time(cpu);
226 idle_ticks = (unsigned int) cputime64_sub(total_idle_ticks,
228 rcpu->prev_idle = total_idle_ticks;
230 /* We do a very dumb calculation to update the LEDs for now,
231 * we'll do better once we have actual PWM implemented
233 load = (9 * (total_ticks - idle_ticks)) / total_ticks;
237 for (i = 0; i < 8; i++) {
238 u8 ub = (load > i) ? 0xff : 0;
239 rm->ubuf[i + offset] = ub;
242 rcpu->zero = (cumm == 0);
244 /* Now check if LEDs are all 0, we can stop DMA */
245 pause = (rm->cpu[0].zero && rm->cpu[1].zero);
246 if (pause != rm->paused) {
247 mutex_lock(&rm->sem);
248 pause = (rm->cpu[0].zero && rm->cpu[1].zero);
249 rackmeter_do_pause(rm, pause);
250 mutex_unlock(&rm->sem);
252 schedule_delayed_work_on(cpu, &rcpu->sniffer,
253 msecs_to_jiffies(CPU_SAMPLING_RATE));
256 static void __devinit rackmeter_init_cpu_sniffer(struct rackmeter *rm)
260 /* This driver works only with 1 or 2 CPUs numbered 0 and 1,
261 * but that's really all we have on Apple Xserve. It doesn't
262 * play very nice with CPU hotplug neither but we don't do that
263 * on those machines yet
266 INIT_WORK(&rm->cpu[0].sniffer, rackmeter_do_timer, rm);
267 INIT_WORK(&rm->cpu[1].sniffer, rackmeter_do_timer, rm);
269 for_each_online_cpu(cpu) {
270 struct rackmeter_cpu *rcpu;
274 rcpu = &rm->cpu[cpu];;
275 rcpu->prev_idle = get_cpu_idle_time(cpu);
276 rcpu->prev_wall = jiffies64_to_cputime64(get_jiffies_64());
277 schedule_delayed_work_on(cpu, &rm->cpu[cpu].sniffer,
278 msecs_to_jiffies(CPU_SAMPLING_RATE));
282 static void __devexit rackmeter_stop_cpu_sniffer(struct rackmeter *rm)
284 cancel_rearming_delayed_work(&rm->cpu[0].sniffer);
285 cancel_rearming_delayed_work(&rm->cpu[1].sniffer);
288 static int rackmeter_setup(struct rackmeter *rm)
290 pr_debug("rackmeter: setting up i2s..\n");
291 rackmeter_setup_i2s(rm);
293 pr_debug("rackmeter: setting up default pattern..\n");
294 rackmeter_set_default_pattern(rm);
296 pr_debug("rackmeter: setting up dbdma..\n");
297 rackmeter_setup_dbdma(rm);
299 pr_debug("rackmeter: start CPU measurements..\n");
300 rackmeter_init_cpu_sniffer(rm);
302 printk(KERN_INFO "RackMeter initialized\n");
307 /* XXX FIXME: No PWM yet, this is 0/1 */
308 static u32 rackmeter_calc_sample(struct rackmeter *rm, unsigned int index)
313 for (led = 0; led < 16; led++) {
315 sample |= ((rm->ubuf[led] >= 0x80) << 15);
317 return (sample << 17) | (sample >> 15);
320 static irqreturn_t rackmeter_irq(int irq, void *arg)
322 struct rackmeter *rm = arg;
323 struct rackmeter_dma *db = rm->dma_buf_v;
324 unsigned int mark, i;
327 /* Flush PCI buffers with an MMIO read. Maybe we could actually
328 * check the status one day ... in case things go wrong, though
329 * this never happened to me
331 (void)in_le32(&rm->dma_regs->status);
333 /* Make sure the CPU gets us in order */
338 if (mark != 1 && mark != 2) {
339 printk(KERN_WARNING "rackmeter: Incorrect DMA mark 0x%08x\n",
341 /* We allow for 3 errors like that (stale DBDMA irqs) */
342 if (++rm->stale_irq > 3) {
343 printk(KERN_ERR "rackmeter: Too many errors,"
345 DBDMA_DO_RESET(rm->dma_regs);
350 /* Next buffer we need to fill is mark value */
351 buf = mark == 1 ? db->buf1 : db->buf2;
353 /* Fill it now. This routine converts the 8 bits depth sample array
354 * into the PWM bitmap for each LED.
356 for (i = 0; i < SAMPLE_COUNT; i++)
357 buf[i] = rackmeter_calc_sample(rm, i);
363 static int __devinit rackmeter_probe(struct macio_dev* mdev,
364 const struct of_device_id *match)
366 struct device_node *i2s = NULL, *np = NULL;
367 struct rackmeter *rm = NULL;
368 struct resource ri2s, rdma;
371 pr_debug("rackmeter_probe()\n");
374 while ((i2s = of_get_next_child(mdev->ofdev.node, i2s)) != NULL)
375 if (strcmp(i2s->name, "i2s-a") == 0)
378 pr_debug(" i2s-a child not found\n");
381 /* Get lightshow or virtual sound */
382 while ((np = of_get_next_child(i2s, np)) != NULL) {
383 if (strcmp(np->name, "lightshow") == 0)
385 if ((strcmp(np->name, "sound") == 0) &&
386 get_property(np, "virtual", NULL) != NULL)
390 pr_debug(" lightshow or sound+virtual child not found\n");
394 /* Create and initialize our instance data */
395 rm = kzalloc(sizeof(struct rackmeter), GFP_KERNEL);
397 printk(KERN_ERR "rackmeter: failed to allocate memory !\n");
403 mutex_init(&rm->sem);
404 dev_set_drvdata(&mdev->ofdev.dev, rm);
405 /* Check resources availability. We need at least resource 0 and 1 */
406 #if 0 /* Use that when i2s-a is finally an mdev per-se */
407 if (macio_resource_count(mdev) < 2 || macio_irq_count(mdev) < 2) {
409 "rackmeter: found match but lacks resources: %s"
410 " (%d resources, %d interrupts)\n",
411 mdev->ofdev.node->full_name);
415 if (macio_request_resources(mdev, "rackmeter")) {
417 "rackmeter: failed to request resources: %s\n",
418 mdev->ofdev.node->full_name);
422 rm->irq = macio_irq(mdev, 1);
424 rm->irq = irq_of_parse_and_map(i2s, 1);
425 if (rm->irq == NO_IRQ ||
426 of_address_to_resource(i2s, 0, &ri2s) ||
427 of_address_to_resource(i2s, 1, &rdma)) {
429 "rackmeter: found match but lacks resources: %s",
430 mdev->ofdev.node->full_name);
436 pr_debug(" i2s @0x%08x\n", (unsigned int)ri2s.start);
437 pr_debug(" dma @0x%08x\n", (unsigned int)rdma.start);
438 pr_debug(" irq %d\n", rm->irq);
440 rm->ubuf = (u8 *)__get_free_page(GFP_KERNEL);
441 if (rm->ubuf == NULL) {
443 "rackmeter: failed to allocate samples page !\n");
448 rm->dma_buf_v = dma_alloc_coherent(&macio_get_pci_dev(mdev)->dev,
449 sizeof(struct rackmeter_dma),
450 &rm->dma_buf_p, GFP_KERNEL);
451 if (rm->dma_buf_v == NULL) {
453 "rackmeter: failed to allocate dma buffer !\n");
455 goto bail_free_samples;
458 rm->i2s_regs = ioremap(macio_resource_start(mdev, 0), 0x1000);
460 rm->i2s_regs = ioremap(ri2s.start, 0x1000);
462 if (rm->i2s_regs == NULL) {
464 "rackmeter: failed to map i2s registers !\n");
469 rm->dma_regs = ioremap(macio_resource_start(mdev, 1), 0x100);
471 rm->dma_regs = ioremap(rdma.start, 0x100);
473 if (rm->dma_regs == NULL) {
475 "rackmeter: failed to map dma registers !\n");
480 rc = rackmeter_setup(rm);
483 "rackmeter: failed to initialize !\n");
488 rc = request_irq(rm->irq, rackmeter_irq, 0, "rackmeter", rm);
491 "rackmeter: failed to request interrupt !\n");
498 DBDMA_DO_RESET(rm->dma_regs);
500 iounmap(rm->dma_regs);
502 iounmap(rm->i2s_regs);
504 dma_free_coherent(&macio_get_pci_dev(mdev)->dev,
505 sizeof(struct rackmeter_dma),
506 rm->dma_buf_v, rm->dma_buf_p);
508 free_page((unsigned long)rm->ubuf);
511 macio_release_resources(mdev);
518 dev_set_drvdata(&mdev->ofdev.dev, NULL);
522 static int __devexit rackmeter_remove(struct macio_dev* mdev)
524 struct rackmeter *rm = dev_get_drvdata(&mdev->ofdev.dev);
526 /* Stop CPU sniffer timer & work queues */
527 rackmeter_stop_cpu_sniffer(rm);
529 /* Clear reference to private data */
530 dev_set_drvdata(&mdev->ofdev.dev, NULL);
532 /* Stop/reset dbdma */
533 DBDMA_DO_RESET(rm->dma_regs);
535 /* Release the IRQ */
536 free_irq(rm->irq, rm);
538 /* Unmap registers */
539 iounmap(rm->dma_regs);
540 iounmap(rm->i2s_regs);
543 dma_free_coherent(&macio_get_pci_dev(mdev)->dev,
544 sizeof(struct rackmeter_dma),
545 rm->dma_buf_v, rm->dma_buf_p);
548 free_page((unsigned long)rm->ubuf);
551 /* Release resources */
552 macio_release_resources(mdev);
561 static int rackmeter_shutdown(struct macio_dev* mdev)
563 struct rackmeter *rm = dev_get_drvdata(&mdev->ofdev.dev);
568 /* Stop CPU sniffer timer & work queues */
569 rackmeter_stop_cpu_sniffer(rm);
571 /* Stop/reset dbdma */
572 DBDMA_DO_RESET(rm->dma_regs);
577 static struct of_device_id rackmeter_match[] = {
582 static struct macio_driver rackmeter_drv = {
584 .owner = THIS_MODULE,
585 .match_table = rackmeter_match,
586 .probe = rackmeter_probe,
587 .remove = rackmeter_remove,
588 .shutdown = rackmeter_shutdown,
592 static int __init rackmeter_init(void)
594 pr_debug("rackmeter_init()\n");
596 return macio_register_driver(&rackmeter_drv);
599 static void __exit rackmeter_exit(void)
601 pr_debug("rackmeter_exit()\n");
603 macio_unregister_driver(&rackmeter_drv);
606 module_init(rackmeter_init);
607 module_exit(rackmeter_exit);
610 MODULE_LICENSE("GPL");
611 MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
612 MODULE_DESCRIPTION("RackMeter: Support vu-meter on XServe front panel");