arch/arm/kernel/etm.c

   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
  30 MODULE_LICENSE("GPL");
  31 MODULE_AUTHOR("Alexander Shishkin");
  32
  33 static struct tracectx tracer;
  34
  35 static inline bool trace_isrunning(struct tracectx *t)
  36 {
  37         return !!(t->flags & TRACER_RUNNING);
  38 }
  39
  40 static 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
  72 static 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
 129 static 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
 169 static 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 */
 193 static 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
 233 static void sysrq_etm_dump(int key, struct tty_struct *tty)
 234 {
 235         dev_dbg(tracer.dev, "Dumping ETB buffer\n");
 236         etm_dump();
 237 }
 238
 239 static struct sysrq_key_op sysrq_etm_op = {
 240         .handler = sysrq_etm_dump,
 241         .help_msg = "ETM buffer dump",
 242         .action_msg = "etm",
 243 };
 244
 245 static 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
 255 static 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
 300 out:
 301         mutex_unlock(&t->mutex);
 302
 303         return length;
 304 }
 305
 306 static int etb_release(struct inode *inode, struct file *file)
 307 {
 308         /* there's nothing to do here, actually */
 309         return 0;
 310 }
 311
 312 static const struct file_operations etb_fops = {
 313         .owner = THIS_MODULE,
 314         .read = etb_read,
 315         .open = etb_open,
 316         .release = etb_release,
 317 };
 318
 319 static struct miscdevice etb_miscdev = {
 320         .name = "tracebuf",
 321         .minor = 0,
 322         .fops = &etb_fops,
 323 };
 324
 325 static 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
 367 out:
 368         return ret;
 369
 370 out_unmap:
 371         amba_set_drvdata(dev, NULL);
 372         iounmap(t->etb_regs);
 373
 374 out_release:
 375         amba_release_regions(dev);
 376
 377         return ret;
 378 }
 379
 380 static 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
 397 static struct amba_id etb_ids[] = {
 398         {
 399                 .id     = 0x0003b907,
 400                 .mask   = 0x0007ffff,
 401         },
 402         { 0, 0 },
 403 };
 404
 405 static 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 */
 416 static 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
 423 static 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
 440 static struct kobj_attribute trace_running_attr =
 441         __ATTR(trace_running, 0644, trace_running_show, trace_running_store);
 442
 443 static 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
 481 static struct kobj_attribute trace_info_attr =
 482         __ATTR(trace_info, 0444, trace_info_show, NULL);
 483
 484 static 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
 493 static 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
 514 static struct kobj_attribute trace_mode_attr =
 515         __ATTR(trace_mode, 0644, trace_mode_show, trace_mode_store);
 516
 517 static 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         ret = etm_readl(t, CSCR_PRSR);
 547
 548         t->ncmppairs = etm_readl(t, ETMR_CONFCODE) & 0xf;
 549         etm_writel(t, 0x440, ETMR_CTRL);
 550         etm_lock(t);
 551
 552         ret = sysfs_create_file(&dev->dev.kobj,
 553                         &trace_running_attr.attr);
 554         if (ret)
 555                 goto out_unmap;
 556
 557         /* failing to create any of these two is not fatal */
 558         ret = sysfs_create_file(&dev->dev.kobj, &trace_info_attr.attr);
 559         if (ret)
 560                 dev_dbg(&dev->dev, "Failed to create trace_info in sysfs\n");
 561
 562         ret = sysfs_create_file(&dev->dev.kobj, &trace_mode_attr.attr);
 563         if (ret)
 564                 dev_dbg(&dev->dev, "Failed to create trace_mode in sysfs\n");
 565
 566         dev_dbg(t->dev, "ETM AMBA driver initialized.\n");
 567
 568 out:
 569         return ret;
 570
 571 out_unmap:
 572         amba_set_drvdata(dev, NULL);
 573         iounmap(t->etm_regs);
 574
 575 out_release:
 576         amba_release_regions(dev);
 577
 578         return ret;
 579 }
 580
 581 static int etm_remove(struct amba_device *dev)
 582 {
 583         struct tracectx *t = amba_get_drvdata(dev);
 584
 585         amba_set_drvdata(dev, NULL);
 586
 587         iounmap(t->etm_regs);
 588         t->etm_regs = NULL;
 589
 590         amba_release_regions(dev);
 591
 592         sysfs_remove_file(&dev->dev.kobj, &trace_running_attr.attr);
 593         sysfs_remove_file(&dev->dev.kobj, &trace_info_attr.attr);
 594         sysfs_remove_file(&dev->dev.kobj, &trace_mode_attr.attr);
 595
 596         return 0;
 597 }
 598
 599 static struct amba_id etm_ids[] = {
 600         {
 601                 .id     = 0x0003b921,
 602                 .mask   = 0x0007ffff,
 603         },
 604         { 0, 0 },
 605 };
 606
 607 static struct amba_driver etm_driver = {
 608         .drv            = {
 609                 .name   = "etm",
 610                 .owner  = THIS_MODULE,
 611         },
 612         .probe          = etm_probe,
 613         .remove         = etm_remove,
 614         .id_table       = etm_ids,
 615 };
 616
 617 static int __init etm_init(void)
 618 {
 619         int retval;
 620
 621         retval = amba_driver_register(&etb_driver);
 622         if (retval) {
 623                 printk(KERN_ERR "Failed to register etb\n");
 624                 return retval;
 625         }
 626
 627         retval = amba_driver_register(&etm_driver);
 628         if (retval) {
 629                 amba_driver_unregister(&etb_driver);
 630                 printk(KERN_ERR "Failed to probe etm\n");
 631                 return retval;
 632         }
 633
 634         /* not being able to install this handler is not fatal */
 635         (void)register_sysrq_key('v', &sysrq_etm_op);
 636
 637         return 0;
 638 }
 639
 640 device_initcall(etm_init);
 641