618 lines · c
1// SPDX-License-Identifier: GPL-2.0-only2/*3 * RackMac vu-meter driver4 *5 * (c) Copyright 2006 Benjamin Herrenschmidt, IBM Corp.6 * <benh@kernel.crashing.org>7 *8 * Support the CPU-meter LEDs of the Xserve G59 *10 * TODO: Implement PWM to do variable intensity and provide userland11 * interface for fun. Also, the CPU-meter could be made nicer by being12 * a bit less "immediate" but giving instead a more average load over13 * time. Patches welcome :-)14 */15#undef DEBUG16 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 25638 39/* CPU meter sampling rate in ms */40#define CPU_SAMPLING_RATE 25041 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 0x7877 78/* This is copied from cpufreq_ondemand, maybe we should put it in79 * a common header somewhere80 */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(kcpustat, 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 proper104 * clock sources105 */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 to110 * handle that. snd-aoa needs that too111 */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 that118 * the OS X driver seems to use. We might want to play around119 * with the clock divisors later120 */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 else140 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 implemented233 */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't263 * play very nice with CPU hotplug neither but we don't do that264 * on those machines yet265 */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 actually331 * check the status one day ... in case things go wrong, though332 * this never happened to me333 */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 array357 * 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(sizeof(*rm), GFP_KERNEL);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_ERR413 "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_ERR421 "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#else428 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_ERR433 "rackmeter: found match but lacks resources: %pOF",434 mdev->ofdev.dev.of_node);435 rc = -ENXIO;436 goto bail_free;437 }438#endif439 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_ERR447 "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_ERR457 "rackmeter: failed to allocate dma buffer !\n");458 rc = -ENOMEM;459 goto bail_free_samples;460 }461#if 0462 rm->i2s_regs = ioremap(macio_resource_start(mdev, 0), 0x1000);463#else464 rm->i2s_regs = ioremap(ri2s.start, 0x1000);465#endif466 if (rm->i2s_regs == NULL) {467 printk(KERN_ERR468 "rackmeter: failed to map i2s registers !\n");469 rc = -ENXIO;470 goto bail_free_dma;471 }472#if 0473 rm->dma_regs = ioremap(macio_resource_start(mdev, 1), 0x100);474#else475 rm->dma_regs = ioremap(rdma.start, 0x100);476#endif477 if (rm->dma_regs == NULL) {478 printk(KERN_ERR479 "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_ERR487 "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_ERR495 "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 0515 macio_release_resources(mdev);516#endif517 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 0555 /* Release resources */556 macio_release_resources(mdev);557#endif558 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 <benh@kernel.crashing.org>");617MODULE_DESCRIPTION("RackMeter: Support vu-meter on XServe front panel");618