1/* 2 * linux/arch/arm/kernel/etm.c 3 * 4 * Driver for ARM's Embedded Trace Macrocell and Embedded Trace Buffer. 5 * 6 * Copyright (C) 2009 Nokia Corporation. 7 * Alexander Shishkin 8 * 9 * This program is free software; you can redistribute it and/or modify 10 * it under the terms of the GNU General Public License version 2 as 11 * published by the Free Software Foundation. 12 */ 13 14#include <linux/kernel.h> 15#include <linux/init.h> 16#include <linux/types.h> 17#include <linux/io.h> 18#include <linux/sysrq.h> 19#include <linux/device.h> 20#include <linux/clk.h> 21#include <linux/amba/bus.h> 22#include <linux/fs.h> 23#include <linux/uaccess.h> 24#include <linux/miscdevice.h> 25#include <linux/vmalloc.h> 26#include <linux/mutex.h> 27#include <asm/hardware/coresight.h> 28#include <asm/sections.h> 29 30MODULE_LICENSE("GPL"); 31MODULE_AUTHOR("Alexander Shishkin"); 32 33static struct tracectx tracer; 34 35static inline bool trace_isrunning(struct tracectx *t) 36{ 37 return !!(t->flags & TRACER_RUNNING); 38} 39 40static int etm_setup_address_range(struct tracectx *t, int n, 41 unsigned long start, unsigned long end, int exclude, int data) 42{ 43 u32 flags = ETMAAT_ARM | ETMAAT_IGNCONTEXTID | ETMAAT_NSONLY | \ 44 ETMAAT_NOVALCMP; 45 46 if (n < 1 || n > t->ncmppairs) 47 return -EINVAL; 48 49 /* comparators and ranges are numbered starting with 1 as opposed 50 * to bits in a word */ 51 n--; 52 53 if (data) 54 flags |= ETMAAT_DLOADSTORE; 55 else 56 flags |= ETMAAT_IEXEC; 57 58 /* first comparator for the range */ 59 etm_writel(t, flags, ETMR_COMP_ACC_TYPE(n * 2)); 60 etm_writel(t, start, ETMR_COMP_VAL(n * 2)); 61 62 /* second comparator is right next to it */ 63 etm_writel(t, flags, ETMR_COMP_ACC_TYPE(n * 2 + 1)); 64 etm_writel(t, end, ETMR_COMP_VAL(n * 2 + 1)); 65 66 flags = exclude ? ETMTE_INCLEXCL : 0; 67 etm_writel(t, flags | (1 << n), ETMR_TRACEENCTRL); 68 69 return 0; 70} 71 72static int trace_start(struct tracectx *t) 73{ 74 u32 v; 75 unsigned long timeout = TRACER_TIMEOUT; 76 77 etb_unlock(t); 78 79 etb_writel(t, 0, ETBR_FORMATTERCTRL); 80 etb_writel(t, 1, ETBR_CTRL); 81 82 etb_lock(t); 83 84 /* configure etm */ 85 v = ETMCTRL_OPTS | ETMCTRL_PROGRAM | ETMCTRL_PORTSIZE(t->etm_portsz); 86 87 if (t->flags & TRACER_CYCLE_ACC) 88 v |= ETMCTRL_CYCLEACCURATE; 89 90 etm_unlock(t); 91 92 etm_writel(t, v, ETMR_CTRL); 93 94 while (!(etm_readl(t, ETMR_CTRL) & ETMCTRL_PROGRAM) && --timeout) 95 ; 96 if (!timeout) { 97 dev_dbg(t->dev, "Waiting for progbit to assert timed out\n"); 98 etm_lock(t); 99 return -EFAULT; 100 } 101 102 etm_setup_address_range(t, 1, (unsigned long)_stext, 103 (unsigned long)_etext, 0, 0); 104 etm_writel(t, 0, ETMR_TRACEENCTRL2); 105 etm_writel(t, 0, ETMR_TRACESSCTRL); 106 etm_writel(t, 0x6f, ETMR_TRACEENEVT); 107 108 v &= ~ETMCTRL_PROGRAM; 109 v |= ETMCTRL_PORTSEL; 110 111 etm_writel(t, v, ETMR_CTRL); 112 113 timeout = TRACER_TIMEOUT; 114 while (etm_readl(t, ETMR_CTRL) & ETMCTRL_PROGRAM && --timeout) 115 ; 116 if (!timeout) { 117 dev_dbg(t->dev, "Waiting for progbit to deassert timed out\n"); 118 etm_lock(t); 119 return -EFAULT; 120 } 121 122 etm_lock(t); 123 124 t->flags |= TRACER_RUNNING; 125 126 return 0; 127} 128 129static int trace_stop(struct tracectx *t) 130{ 131 unsigned long timeout = TRACER_TIMEOUT; 132 133 etm_unlock(t); 134 135 etm_writel(t, 0x440, ETMR_CTRL); 136 while (!(etm_readl(t, ETMR_CTRL) & ETMCTRL_PROGRAM) && --timeout) 137 ; 138 if (!timeout) { 139 dev_dbg(t->dev, "Waiting for progbit to assert timed out\n"); 140 etm_lock(t); 141 return -EFAULT; 142 } 143 144 etm_lock(t); 145 146 etb_unlock(t); 147 etb_writel(t, ETBFF_MANUAL_FLUSH, ETBR_FORMATTERCTRL); 148 149 timeout = TRACER_TIMEOUT; 150 while (etb_readl(t, ETBR_FORMATTERCTRL) & 151 ETBFF_MANUAL_FLUSH && --timeout) 152 ; 153 if (!timeout) { 154 dev_dbg(t->dev, "Waiting for formatter flush to commence " 155 "timed out\n"); 156 etb_lock(t); 157 return -EFAULT; 158 } 159 160 etb_writel(t, 0, ETBR_CTRL); 161 162 etb_lock(t); 163 164 t->flags &= ~TRACER_RUNNING; 165 166 return 0; 167} 168 169static int etb_getdatalen(struct tracectx *t) 170{ 171 u32 v; 172 int rp, wp; 173 174 v = etb_readl(t, ETBR_STATUS); 175 176 if (v & 1) 177 return t->etb_bufsz; 178 179 rp = etb_readl(t, ETBR_READADDR); 180 wp = etb_readl(t, ETBR_WRITEADDR); 181 182 if (rp > wp) { 183 etb_writel(t, 0, ETBR_READADDR); 184 etb_writel(t, 0, ETBR_WRITEADDR); 185 186 return 0; 187 } 188 189 return wp - rp; 190} 191 192/* sysrq+v will always stop the running trace and leave it at that */ 193static void etm_dump(void) 194{ 195 struct tracectx *t = &tracer; 196 u32 first = 0; 197 int length; 198 199 if (!t->etb_regs) { 200 printk(KERN_INFO "No tracing hardware found\n"); 201 return; 202 } 203 204 if (trace_isrunning(t)) 205 trace_stop(t); 206 207 etb_unlock(t); 208 209 length = etb_getdatalen(t); 210 211 if (length == t->etb_bufsz) 212 first = etb_readl(t, ETBR_WRITEADDR); 213 214 etb_writel(t, first, ETBR_READADDR); 215 216 printk(KERN_INFO "Trace buffer contents length: %d\n", length); 217 printk(KERN_INFO "--- ETB buffer begin ---\n"); 218 for (; length; length--) 219 printk("%08x", cpu_to_be32(etb_readl(t, ETBR_READMEM))); 220 printk(KERN_INFO "\n--- ETB buffer end ---\n"); 221 222 /* deassert the overflow bit */ 223 etb_writel(t, 1, ETBR_CTRL); 224 etb_writel(t, 0, ETBR_CTRL); 225 226 etb_writel(t, 0, ETBR_TRIGGERCOUNT); 227 etb_writel(t, 0, ETBR_READADDR); 228 etb_writel(t, 0, ETBR_WRITEADDR); 229 230 etb_lock(t); 231} 232 233static void sysrq_etm_dump(int key) 234{ 235 dev_dbg(tracer.dev, "Dumping ETB buffer\n"); 236 etm_dump(); 237} 238 239static struct sysrq_key_op sysrq_etm_op = { 240 .handler = sysrq_etm_dump, 241 .help_msg = "ETM buffer dump", 242 .action_msg = "etm", 243}; 244 245static int etb_open(struct inode *inode, struct file *file) 246{ 247 if (!tracer.etb_regs) 248 return -ENODEV; 249 250 file->private_data = &tracer; 251 252 return nonseekable_open(inode, file); 253} 254 255static ssize_t etb_read(struct file *file, char __user *data, 256 size_t len, loff_t *ppos) 257{ 258 int total, i; 259 long length; 260 struct tracectx *t = file->private_data; 261 u32 first = 0; 262 u32 *buf; 263 264 mutex_lock(&t->mutex); 265 266 if (trace_isrunning(t)) { 267 length = 0; 268 goto out; 269 } 270 271 etb_unlock(t); 272 273 total = etb_getdatalen(t); 274 if (total == t->etb_bufsz) 275 first = etb_readl(t, ETBR_WRITEADDR); 276 277 etb_writel(t, first, ETBR_READADDR); 278 279 length = min(total * 4, (int)len); 280 buf = vmalloc(length); 281 282 dev_dbg(t->dev, "ETB buffer length: %d\n", total); 283 dev_dbg(t->dev, "ETB status reg: %x\n", etb_readl(t, ETBR_STATUS)); 284 for (i = 0; i < length / 4; i++) 285 buf[i] = etb_readl(t, ETBR_READMEM); 286 287 /* the only way to deassert overflow bit in ETB status is this */ 288 etb_writel(t, 1, ETBR_CTRL); 289 etb_writel(t, 0, ETBR_CTRL); 290 291 etb_writel(t, 0, ETBR_WRITEADDR); 292 etb_writel(t, 0, ETBR_READADDR); 293 etb_writel(t, 0, ETBR_TRIGGERCOUNT); 294 295 etb_lock(t); 296 297 length -= copy_to_user(data, buf, length); 298 vfree(buf); 299 300out: 301 mutex_unlock(&t->mutex); 302 303 return length; 304} 305 306static int etb_release(struct inode *inode, struct file *file) 307{ 308 /* there's nothing to do here, actually */ 309 return 0; 310} 311 312static const struct file_operations etb_fops = { 313 .owner = THIS_MODULE, 314 .read = etb_read, 315 .open = etb_open, 316 .release = etb_release, 317}; 318 319static struct miscdevice etb_miscdev = { 320 .name = "tracebuf", 321 .minor = 0, 322 .fops = &etb_fops, 323}; 324 325static int __init etb_probe(struct amba_device *dev, struct amba_id *id) 326{ 327 struct tracectx *t = &tracer; 328 int ret = 0; 329 330 ret = amba_request_regions(dev, NULL); 331 if (ret) 332 goto out; 333 334 t->etb_regs = ioremap_nocache(dev->res.start, resource_size(&dev->res)); 335 if (!t->etb_regs) { 336 ret = -ENOMEM; 337 goto out_release; 338 } 339 340 amba_set_drvdata(dev, t); 341 342 etb_miscdev.parent = &dev->dev; 343 344 ret = misc_register(&etb_miscdev); 345 if (ret) 346 goto out_unmap; 347 348 t->emu_clk = clk_get(&dev->dev, "emu_src_ck"); 349 if (IS_ERR(t->emu_clk)) { 350 dev_dbg(&dev->dev, "Failed to obtain emu_src_ck.\n"); 351 return -EFAULT; 352 } 353 354 clk_enable(t->emu_clk); 355 356 etb_unlock(t); 357 t->etb_bufsz = etb_readl(t, ETBR_DEPTH); 358 dev_dbg(&dev->dev, "Size: %x\n", t->etb_bufsz); 359 360 /* make sure trace capture is disabled */ 361 etb_writel(t, 0, ETBR_CTRL); 362 etb_writel(t, 0x1000, ETBR_FORMATTERCTRL); 363 etb_lock(t); 364 365 dev_dbg(&dev->dev, "ETB AMBA driver initialized.\n"); 366 367out: 368 return ret; 369 370out_unmap: 371 amba_set_drvdata(dev, NULL); 372 iounmap(t->etb_regs); 373 374out_release: 375 amba_release_regions(dev); 376 377 return ret; 378} 379 380static int etb_remove(struct amba_device *dev) 381{ 382 struct tracectx *t = amba_get_drvdata(dev); 383 384 amba_set_drvdata(dev, NULL); 385 386 iounmap(t->etb_regs); 387 t->etb_regs = NULL; 388 389 clk_disable(t->emu_clk); 390 clk_put(t->emu_clk); 391 392 amba_release_regions(dev); 393 394 return 0; 395} 396 397static struct amba_id etb_ids[] = { 398 { 399 .id = 0x0003b907, 400 .mask = 0x0007ffff, 401 }, 402 { 0, 0 }, 403}; 404 405static struct amba_driver etb_driver = { 406 .drv = { 407 .name = "etb", 408 .owner = THIS_MODULE, 409 }, 410 .probe = etb_probe, 411 .remove = etb_remove, 412 .id_table = etb_ids, 413}; 414 415/* use a sysfs file "trace_running" to start/stop tracing */ 416static ssize_t trace_running_show(struct kobject *kobj, 417 struct kobj_attribute *attr, 418 char *buf) 419{ 420 return sprintf(buf, "%x\n", trace_isrunning(&tracer)); 421} 422 423static ssize_t trace_running_store(struct kobject *kobj, 424 struct kobj_attribute *attr, 425 const char *buf, size_t n) 426{ 427 unsigned int value; 428 int ret; 429 430 if (sscanf(buf, "%u", &value) != 1) 431 return -EINVAL; 432 433 mutex_lock(&tracer.mutex); 434 ret = value ? trace_start(&tracer) : trace_stop(&tracer); 435 mutex_unlock(&tracer.mutex); 436 437 return ret ? : n; 438} 439 440static struct kobj_attribute trace_running_attr = 441 __ATTR(trace_running, 0644, trace_running_show, trace_running_store); 442 443static ssize_t trace_info_show(struct kobject *kobj, 444 struct kobj_attribute *attr, 445 char *buf) 446{ 447 u32 etb_wa, etb_ra, etb_st, etb_fc, etm_ctrl, etm_st; 448 int datalen; 449 450 etb_unlock(&tracer); 451 datalen = etb_getdatalen(&tracer); 452 etb_wa = etb_readl(&tracer, ETBR_WRITEADDR); 453 etb_ra = etb_readl(&tracer, ETBR_READADDR); 454 etb_st = etb_readl(&tracer, ETBR_STATUS); 455 etb_fc = etb_readl(&tracer, ETBR_FORMATTERCTRL); 456 etb_lock(&tracer); 457 458 etm_unlock(&tracer); 459 etm_ctrl = etm_readl(&tracer, ETMR_CTRL); 460 etm_st = etm_readl(&tracer, ETMR_STATUS); 461 etm_lock(&tracer); 462 463 return sprintf(buf, "Trace buffer len: %d\nComparator pairs: %d\n" 464 "ETBR_WRITEADDR:\t%08x\n" 465 "ETBR_READADDR:\t%08x\n" 466 "ETBR_STATUS:\t%08x\n" 467 "ETBR_FORMATTERCTRL:\t%08x\n" 468 "ETMR_CTRL:\t%08x\n" 469 "ETMR_STATUS:\t%08x\n", 470 datalen, 471 tracer.ncmppairs, 472 etb_wa, 473 etb_ra, 474 etb_st, 475 etb_fc, 476 etm_ctrl, 477 etm_st 478 ); 479} 480 481static struct kobj_attribute trace_info_attr = 482 __ATTR(trace_info, 0444, trace_info_show, NULL); 483 484static ssize_t trace_mode_show(struct kobject *kobj, 485 struct kobj_attribute *attr, 486 char *buf) 487{ 488 return sprintf(buf, "%d %d\n", 489 !!(tracer.flags & TRACER_CYCLE_ACC), 490 tracer.etm_portsz); 491} 492 493static ssize_t trace_mode_store(struct kobject *kobj, 494 struct kobj_attribute *attr, 495 const char *buf, size_t n) 496{ 497 unsigned int cycacc, portsz; 498 499 if (sscanf(buf, "%u %u", &cycacc, &portsz) != 2) 500 return -EINVAL; 501 502 mutex_lock(&tracer.mutex); 503 if (cycacc) 504 tracer.flags |= TRACER_CYCLE_ACC; 505 else 506 tracer.flags &= ~TRACER_CYCLE_ACC; 507 508 tracer.etm_portsz = portsz & 0x0f; 509 mutex_unlock(&tracer.mutex); 510 511 return n; 512} 513 514static struct kobj_attribute trace_mode_attr = 515 __ATTR(trace_mode, 0644, trace_mode_show, trace_mode_store); 516 517static int __init etm_probe(struct amba_device *dev, struct amba_id *id) 518{ 519 struct tracectx *t = &tracer; 520 int ret = 0; 521 522 if (t->etm_regs) { 523 dev_dbg(&dev->dev, "ETM already initialized\n"); 524 ret = -EBUSY; 525 goto out; 526 } 527 528 ret = amba_request_regions(dev, NULL); 529 if (ret) 530 goto out; 531 532 t->etm_regs = ioremap_nocache(dev->res.start, resource_size(&dev->res)); 533 if (!t->etm_regs) { 534 ret = -ENOMEM; 535 goto out_release; 536 } 537 538 amba_set_drvdata(dev, t); 539 540 mutex_init(&t->mutex); 541 t->dev = &dev->dev; 542 t->flags = TRACER_CYCLE_ACC; 543 t->etm_portsz = 1; 544 545 etm_unlock(t); 546 (void)etm_readl(t, ETMMR_PDSR); 547 /* dummy first read */ 548 (void)etm_readl(&tracer, ETMMR_OSSRR); 549 550 t->ncmppairs = etm_readl(t, ETMR_CONFCODE) & 0xf; 551 etm_writel(t, 0x440, ETMR_CTRL); 552 etm_lock(t); 553 554 ret = sysfs_create_file(&dev->dev.kobj, 555 &trace_running_attr.attr); 556 if (ret) 557 goto out_unmap; 558 559 /* failing to create any of these two is not fatal */ 560 ret = sysfs_create_file(&dev->dev.kobj, &trace_info_attr.attr); 561 if (ret) 562 dev_dbg(&dev->dev, "Failed to create trace_info in sysfs\n"); 563 564 ret = sysfs_create_file(&dev->dev.kobj, &trace_mode_attr.attr); 565 if (ret) 566 dev_dbg(&dev->dev, "Failed to create trace_mode in sysfs\n"); 567 568 dev_dbg(t->dev, "ETM AMBA driver initialized.\n"); 569 570out: 571 return ret; 572 573out_unmap: 574 amba_set_drvdata(dev, NULL); 575 iounmap(t->etm_regs); 576 577out_release: 578 amba_release_regions(dev); 579 580 return ret; 581} 582 583static int etm_remove(struct amba_device *dev) 584{ 585 struct tracectx *t = amba_get_drvdata(dev); 586 587 amba_set_drvdata(dev, NULL); 588 589 iounmap(t->etm_regs); 590 t->etm_regs = NULL; 591 592 amba_release_regions(dev); 593 594 sysfs_remove_file(&dev->dev.kobj, &trace_running_attr.attr); 595 sysfs_remove_file(&dev->dev.kobj, &trace_info_attr.attr); 596 sysfs_remove_file(&dev->dev.kobj, &trace_mode_attr.attr); 597 598 return 0; 599} 600 601static struct amba_id etm_ids[] = { 602 { 603 .id = 0x0003b921, 604 .mask = 0x0007ffff, 605 }, 606 { 0, 0 }, 607}; 608 609static struct amba_driver etm_driver = { 610 .drv = { 611 .name = "etm", 612 .owner = THIS_MODULE, 613 }, 614 .probe = etm_probe, 615 .remove = etm_remove, 616 .id_table = etm_ids, 617}; 618 619static int __init etm_init(void) 620{ 621 int retval; 622 623 retval = amba_driver_register(&etb_driver); 624 if (retval) { 625 printk(KERN_ERR "Failed to register etb\n"); 626 return retval; 627 } 628 629 retval = amba_driver_register(&etm_driver); 630 if (retval) { 631 amba_driver_unregister(&etb_driver); 632 printk(KERN_ERR "Failed to probe etm\n"); 633 return retval; 634 } 635 636 /* not being able to install this handler is not fatal */ 637 (void)register_sysrq_key('v', &sysrq_etm_op); 638 639 return 0; 640} 641 642device_initcall(etm_init); 643