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 /*
  34  * ETM tracer state
  35  */
  36 struct tracectx {
  37         unsigned int    etb_bufsz;
  38         void __iomem    *etb_regs;
  39         void __iomem    *etm_regs;
  40         unsigned long   flags;
  41         int             ncmppairs;
  42         int             etm_portsz;
  43         struct device   *dev;
  44         struct clk      *emu_clk;
  45         struct mutex    mutex;
  46 };
  47
  48 static struct tracectx tracer;
  49
  50 static inline bool trace_isrunning(struct tracectx *t)
  51 {
  52         return !!(t->flags & TRACER_RUNNING);
  53 }
  54
  55 static int etm_setup_address_range(struct tracectx *t, int n,
  56                 unsigned long start, unsigned long end, int exclude, int data)
  57 {
  58         u32 flags = ETMAAT_ARM | ETMAAT_IGNCONTEXTID | ETMAAT_NSONLY | \
  59                     ETMAAT_NOVALCMP;
  60
  61         if (n < 1 || n > t->ncmppairs)
  62                 return -EINVAL;
  63
  64         /* comparators and ranges are numbered starting with 1 as opposed
  65          * to bits in a word */
  66         n--;
  67
  68         if (data)
  69                 flags |= ETMAAT_DLOADSTORE;
  70         else
  71                 flags |= ETMAAT_IEXEC;
  72
  73         /* first comparator for the range */
  74         etm_writel(t, flags, ETMR_COMP_ACC_TYPE(n * 2));
  75         etm_writel(t, start, ETMR_COMP_VAL(n * 2));
  76
  77         /* second comparator is right next to it */
  78         etm_writel(t, flags, ETMR_COMP_ACC_TYPE(n * 2 + 1));
  79         etm_writel(t, end, ETMR_COMP_VAL(n * 2 + 1));
  80
  81         flags = exclude ? ETMTE_INCLEXCL : 0;
  82         etm_writel(t, flags | (1 << n), ETMR_TRACEENCTRL);
  83
  84         return 0;
  85 }
  86
  87 static int trace_start(struct tracectx *t)
  88 {
  89         u32 v;
  90         unsigned long timeout = TRACER_TIMEOUT;
  91
  92         etb_unlock(t);
  93
  94         etb_writel(t, 0, ETBR_FORMATTERCTRL);
  95         etb_writel(t, 1, ETBR_CTRL);
  96
  97         etb_lock(t);
  98
  99         /* configure etm */
 100         v = ETMCTRL_OPTS | ETMCTRL_PROGRAM | ETMCTRL_PORTSIZE(t->etm_portsz);
 101
 102         if (t->flags & TRACER_CYCLE_ACC)
 103                 v |= ETMCTRL_CYCLEACCURATE;
 104
 105         etm_unlock(t);
 106
 107         etm_writel(t, v, ETMR_CTRL);
 108
 109         while (!(etm_readl(t, ETMR_CTRL) & ETMCTRL_PROGRAM) && --timeout)
 110                 ;
 111         if (!timeout) {
 112                 dev_dbg(t->dev, "Waiting for progbit to assert timed out\n");
 113                 etm_lock(t);
 114                 return -EFAULT;
 115         }
 116
 117         etm_setup_address_range(t, 1, (unsigned long)_stext,
 118                         (unsigned long)_etext, 0, 0);
 119         etm_writel(t, 0, ETMR_TRACEENCTRL2);
 120         etm_writel(t, 0, ETMR_TRACESSCTRL);
 121         etm_writel(t, 0x6f, ETMR_TRACEENEVT);
 122
 123         v &= ~ETMCTRL_PROGRAM;
 124         v |= ETMCTRL_PORTSEL;
 125
 126         etm_writel(t, v, ETMR_CTRL);
 127
 128         timeout = TRACER_TIMEOUT;
 129         while (etm_readl(t, ETMR_CTRL) & ETMCTRL_PROGRAM && --timeout)
 130                 ;
 131         if (!timeout) {
 132                 dev_dbg(t->dev, "Waiting for progbit to deassert timed out\n");
 133                 etm_lock(t);
 134                 return -EFAULT;
 135         }
 136
 137         etm_lock(t);
 138
 139         t->flags |= TRACER_RUNNING;
 140
 141         return 0;
 142 }
 143
 144 static int trace_stop(struct tracectx *t)
 145 {
 146         unsigned long timeout = TRACER_TIMEOUT;
 147
 148         etm_unlock(t);
 149
 150         etm_writel(t, 0x440, ETMR_CTRL);
 151         while (!(etm_readl(t, ETMR_CTRL) & ETMCTRL_PROGRAM) && --timeout)
 152                 ;
 153         if (!timeout) {
 154                 dev_dbg(t->dev, "Waiting for progbit to assert timed out\n");
 155                 etm_lock(t);
 156                 return -EFAULT;
 157         }
 158
 159         etm_lock(t);
 160
 161         etb_unlock(t);
 162         etb_writel(t, ETBFF_MANUAL_FLUSH, ETBR_FORMATTERCTRL);
 163
 164         timeout = TRACER_TIMEOUT;
 165         while (etb_readl(t, ETBR_FORMATTERCTRL) &
 166                         ETBFF_MANUAL_FLUSH && --timeout)
 167                 ;
 168         if (!timeout) {
 169                 dev_dbg(t->dev, "Waiting for formatter flush to commence "
 170                                 "timed out\n");
 171                 etb_lock(t);
 172                 return -EFAULT;
 173         }
 174
 175         etb_writel(t, 0, ETBR_CTRL);
 176
 177         etb_lock(t);
 178
 179         t->flags &= ~TRACER_RUNNING;
 180
 181         return 0;
 182 }
 183
 184 static int etb_getdatalen(struct tracectx *t)
 185 {
 186         u32 v;
 187         int rp, wp;
 188
 189         v = etb_readl(t, ETBR_STATUS);
 190
 191         if (v & 1)
 192                 return t->etb_bufsz;
 193
 194         rp = etb_readl(t, ETBR_READADDR);
 195         wp = etb_readl(t, ETBR_WRITEADDR);
 196
 197         if (rp > wp) {
 198                 etb_writel(t, 0, ETBR_READADDR);
 199                 etb_writel(t, 0, ETBR_WRITEADDR);
 200
 201                 return 0;
 202         }
 203
 204         return wp - rp;
 205 }
 206
 207 /* sysrq+v will always stop the running trace and leave it at that */
 208 static void etm_dump(void)
 209 {
 210         struct tracectx *t = &tracer;
 211         u32 first = 0;
 212         int length;
 213
 214         if (!t->etb_regs) {
 215                 printk(KERN_INFO "No tracing hardware found\n");
 216                 return;
 217         }
 218
 219         if (trace_isrunning(t))
 220                 trace_stop(t);
 221
 222         etb_unlock(t);
 223
 224         length = etb_getdatalen(t);
 225
 226         if (length == t->etb_bufsz)
 227                 first = etb_readl(t, ETBR_WRITEADDR);
 228
 229         etb_writel(t, first, ETBR_READADDR);
 230
 231         printk(KERN_INFO "Trace buffer contents length: %d\n", length);
 232         printk(KERN_INFO "--- ETB buffer begin ---\n");
 233         for (; length; length--)
 234                 printk("%08x", cpu_to_be32(etb_readl(t, ETBR_READMEM)));
 235         printk(KERN_INFO "\n--- ETB buffer end ---\n");
 236
 237         /* deassert the overflow bit */
 238         etb_writel(t, 1, ETBR_CTRL);
 239         etb_writel(t, 0, ETBR_CTRL);
 240
 241         etb_writel(t, 0, ETBR_TRIGGERCOUNT);
 242         etb_writel(t, 0, ETBR_READADDR);
 243         etb_writel(t, 0, ETBR_WRITEADDR);
 244
 245         etb_lock(t);
 246 }
 247
 248 static void sysrq_etm_dump(int key)
 249 {
 250         dev_dbg(tracer.dev, "Dumping ETB buffer\n");
 251         etm_dump();
 252 }
 253
 254 static struct sysrq_key_op sysrq_etm_op = {
 255         .handler = sysrq_etm_dump,
 256         .help_msg = "ETM buffer dump",
 257         .action_msg = "etm",
 258 };
 259
 260 static int etb_open(struct inode *inode, struct file *file)
 261 {
 262         if (!tracer.etb_regs)
 263                 return -ENODEV;
 264
 265         file->private_data = &tracer;
 266
 267         return nonseekable_open(inode, file);
 268 }
 269
 270 static ssize_t etb_read(struct file *file, char __user *data,
 271                 size_t len, loff_t *ppos)
 272 {
 273         int total, i;
 274         long length;
 275         struct tracectx *t = file->private_data;
 276         u32 first = 0;
 277         u32 *buf;
 278
 279         mutex_lock(&t->mutex);
 280
 281         if (trace_isrunning(t)) {
 282                 length = 0;
 283                 goto out;
 284         }
 285
 286         etb_unlock(t);
 287
 288         total = etb_getdatalen(t);
 289         if (total == t->etb_bufsz)
 290                 first = etb_readl(t, ETBR_WRITEADDR);
 291
 292         etb_writel(t, first, ETBR_READADDR);
 293
 294         length = min(total * 4, (int)len);
 295         buf = vmalloc(length);
 296
 297         dev_dbg(t->dev, "ETB buffer length: %d\n", total);
 298         dev_dbg(t->dev, "ETB status reg: %x\n", etb_readl(t, ETBR_STATUS));
 299         for (i = 0; i < length / 4; i++)
 300                 buf[i] = etb_readl(t, ETBR_READMEM);
 301
 302         /* the only way to deassert overflow bit in ETB status is this */
 303         etb_writel(t, 1, ETBR_CTRL);
 304         etb_writel(t, 0, ETBR_CTRL);
 305
 306         etb_writel(t, 0, ETBR_WRITEADDR);
 307         etb_writel(t, 0, ETBR_READADDR);
 308         etb_writel(t, 0, ETBR_TRIGGERCOUNT);
 309
 310         etb_lock(t);
 311
 312         length -= copy_to_user(data, buf, length);
 313         vfree(buf);
 314
 315 out:
 316         mutex_unlock(&t->mutex);
 317
 318         return length;
 319 }
 320
 321 static int etb_release(struct inode *inode, struct file *file)
 322 {
 323         /* there's nothing to do here, actually */
 324         return 0;
 325 }
 326
 327 static const struct file_operations etb_fops = {
 328         .owner = THIS_MODULE,
 329         .read = etb_read,
 330         .open = etb_open,
 331         .release = etb_release,
 332         .llseek = no_llseek,
 333 };
 334
 335 static struct miscdevice etb_miscdev = {
 336         .name = "tracebuf",
 337         .minor = 0,
 338         .fops = &etb_fops,
 339 };
 340
 341 static int __init etb_probe(struct amba_device *dev, struct amba_id *id)
 342 {
 343         struct tracectx *t = &tracer;
 344         int ret = 0;
 345
 346         ret = amba_request_regions(dev, NULL);
 347         if (ret)
 348                 goto out;
 349
 350         t->etb_regs = ioremap_nocache(dev->res.start, resource_size(&dev->res));
 351         if (!t->etb_regs) {
 352                 ret = -ENOMEM;
 353                 goto out_release;
 354         }
 355
 356         amba_set_drvdata(dev, t);
 357
 358         etb_miscdev.parent = &dev->dev;
 359
 360         ret = misc_register(&etb_miscdev);
 361         if (ret)
 362                 goto out_unmap;
 363
 364         t->emu_clk = clk_get(&dev->dev, "emu_src_ck");
 365         if (IS_ERR(t->emu_clk)) {
 366                 dev_dbg(&dev->dev, "Failed to obtain emu_src_ck.\n");
 367                 return -EFAULT;
 368         }
 369
 370         clk_enable(t->emu_clk);
 371
 372         etb_unlock(t);
 373         t->etb_bufsz = etb_readl(t, ETBR_DEPTH);
 374         dev_dbg(&dev->dev, "Size: %x\n", t->etb_bufsz);
 375
 376         /* make sure trace capture is disabled */
 377         etb_writel(t, 0, ETBR_CTRL);
 378         etb_writel(t, 0x1000, ETBR_FORMATTERCTRL);
 379         etb_lock(t);
 380
 381         dev_dbg(&dev->dev, "ETB AMBA driver initialized.\n");
 382
 383 out:
 384         return ret;
 385
 386 out_unmap:
 387         amba_set_drvdata(dev, NULL);
 388         iounmap(t->etb_regs);
 389
 390 out_release:
 391         amba_release_regions(dev);
 392
 393         return ret;
 394 }
 395
 396 static int etb_remove(struct amba_device *dev)
 397 {
 398         struct tracectx *t = amba_get_drvdata(dev);
 399
 400         amba_set_drvdata(dev, NULL);
 401
 402         iounmap(t->etb_regs);
 403         t->etb_regs = NULL;
 404
 405         clk_disable(t->emu_clk);
 406         clk_put(t->emu_clk);
 407
 408         amba_release_regions(dev);
 409
 410         return 0;
 411 }
 412
 413 static struct amba_id etb_ids[] = {
 414         {
 415                 .id     = 0x0003b907,
 416                 .mask   = 0x0007ffff,
 417         },
 418         { 0, 0 },
 419 };
 420
 421 static struct amba_driver etb_driver = {
 422         .drv            = {
 423                 .name   = "etb",
 424                 .owner  = THIS_MODULE,
 425         },
 426         .probe          = etb_probe,
 427         .remove         = etb_remove,
 428         .id_table       = etb_ids,
 429 };
 430
 431 /* use a sysfs file "trace_running" to start/stop tracing */
 432 static ssize_t trace_running_show(struct kobject *kobj,
 433                                   struct kobj_attribute *attr,
 434                                   char *buf)
 435 {
 436         return sprintf(buf, "%x\n", trace_isrunning(&tracer));
 437 }
 438
 439 static ssize_t trace_running_store(struct kobject *kobj,
 440                                    struct kobj_attribute *attr,
 441                                    const char *buf, size_t n)
 442 {
 443         unsigned int value;
 444         int ret;
 445
 446         if (sscanf(buf, "%u", &value) != 1)
 447                 return -EINVAL;
 448
 449         mutex_lock(&tracer.mutex);
 450         ret = value ? trace_start(&tracer) : trace_stop(&tracer);
 451         mutex_unlock(&tracer.mutex);
 452
 453         return ret ? : n;
 454 }
 455
 456 static struct kobj_attribute trace_running_attr =
 457         __ATTR(trace_running, 0644, trace_running_show, trace_running_store);
 458
 459 static ssize_t trace_info_show(struct kobject *kobj,
 460                                   struct kobj_attribute *attr,
 461                                   char *buf)
 462 {
 463         u32 etb_wa, etb_ra, etb_st, etb_fc, etm_ctrl, etm_st;
 464         int datalen;
 465
 466         etb_unlock(&tracer);
 467         datalen = etb_getdatalen(&tracer);
 468         etb_wa = etb_readl(&tracer, ETBR_WRITEADDR);
 469         etb_ra = etb_readl(&tracer, ETBR_READADDR);
 470         etb_st = etb_readl(&tracer, ETBR_STATUS);
 471         etb_fc = etb_readl(&tracer, ETBR_FORMATTERCTRL);
 472         etb_lock(&tracer);
 473
 474         etm_unlock(&tracer);
 475         etm_ctrl = etm_readl(&tracer, ETMR_CTRL);
 476         etm_st = etm_readl(&tracer, ETMR_STATUS);
 477         etm_lock(&tracer);
 478
 479         return sprintf(buf, "Trace buffer len: %d\nComparator pairs: %d\n"
 480                         "ETBR_WRITEADDR:\t%08x\n"
 481                         "ETBR_READADDR:\t%08x\n"
 482                         "ETBR_STATUS:\t%08x\n"
 483                         "ETBR_FORMATTERCTRL:\t%08x\n"
 484                         "ETMR_CTRL:\t%08x\n"
 485                         "ETMR_STATUS:\t%08x\n",
 486                         datalen,
 487                         tracer.ncmppairs,
 488                         etb_wa,
 489                         etb_ra,
 490                         etb_st,
 491                         etb_fc,
 492                         etm_ctrl,
 493                         etm_st
 494                         );
 495 }
 496
 497 static struct kobj_attribute trace_info_attr =
 498         __ATTR(trace_info, 0444, trace_info_show, NULL);
 499
 500 static ssize_t trace_mode_show(struct kobject *kobj,
 501                                   struct kobj_attribute *attr,
 502                                   char *buf)
 503 {
 504         return sprintf(buf, "%d %d\n",
 505                         !!(tracer.flags & TRACER_CYCLE_ACC),
 506                         tracer.etm_portsz);
 507 }
 508
 509 static ssize_t trace_mode_store(struct kobject *kobj,
 510                                    struct kobj_attribute *attr,
 511                                    const char *buf, size_t n)
 512 {
 513         unsigned int cycacc, portsz;
 514
 515         if (sscanf(buf, "%u %u", &cycacc, &portsz) != 2)
 516                 return -EINVAL;
 517
 518         mutex_lock(&tracer.mutex);
 519         if (cycacc)
 520                 tracer.flags |= TRACER_CYCLE_ACC;
 521         else
 522                 tracer.flags &= ~TRACER_CYCLE_ACC;
 523
 524         tracer.etm_portsz = portsz & 0x0f;
 525         mutex_unlock(&tracer.mutex);
 526
 527         return n;
 528 }
 529
 530 static struct kobj_attribute trace_mode_attr =
 531         __ATTR(trace_mode, 0644, trace_mode_show, trace_mode_store);
 532
 533 static int __init etm_probe(struct amba_device *dev, struct amba_id *id)
 534 {
 535         struct tracectx *t = &tracer;
 536         int ret = 0;
 537
 538         if (t->etm_regs) {
 539                 dev_dbg(&dev->dev, "ETM already initialized\n");
 540                 ret = -EBUSY;
 541                 goto out;
 542         }
 543
 544         ret = amba_request_regions(dev, NULL);
 545         if (ret)
 546                 goto out;
 547
 548         t->etm_regs = ioremap_nocache(dev->res.start, resource_size(&dev->res));
 549         if (!t->etm_regs) {
 550                 ret = -ENOMEM;
 551                 goto out_release;
 552         }
 553
 554         amba_set_drvdata(dev, t);
 555
 556         mutex_init(&t->mutex);
 557         t->dev = &dev->dev;
 558         t->flags = TRACER_CYCLE_ACC;
 559         t->etm_portsz = 1;
 560
 561         etm_unlock(t);
 562         (void)etm_readl(t, ETMMR_PDSR);
 563         /* dummy first read */
 564         (void)etm_readl(&tracer, ETMMR_OSSRR);
 565
 566         t->ncmppairs = etm_readl(t, ETMR_CONFCODE) & 0xf;
 567         etm_writel(t, 0x440, ETMR_CTRL);
 568         etm_lock(t);
 569
 570         ret = sysfs_create_file(&dev->dev.kobj,
 571                         &trace_running_attr.attr);
 572         if (ret)
 573                 goto out_unmap;
 574
 575         /* failing to create any of these two is not fatal */
 576         ret = sysfs_create_file(&dev->dev.kobj, &trace_info_attr.attr);
 577         if (ret)
 578                 dev_dbg(&dev->dev, "Failed to create trace_info in sysfs\n");
 579
 580         ret = sysfs_create_file(&dev->dev.kobj, &trace_mode_attr.attr);
 581         if (ret)
 582                 dev_dbg(&dev->dev, "Failed to create trace_mode in sysfs\n");
 583
 584         dev_dbg(t->dev, "ETM AMBA driver initialized.\n");
 585
 586 out:
 587         return ret;
 588
 589 out_unmap:
 590         amba_set_drvdata(dev, NULL);
 591         iounmap(t->etm_regs);
 592
 593 out_release:
 594         amba_release_regions(dev);
 595
 596         return ret;
 597 }
 598
 599 static int etm_remove(struct amba_device *dev)
 600 {
 601         struct tracectx *t = amba_get_drvdata(dev);
 602
 603         amba_set_drvdata(dev, NULL);
 604
 605         iounmap(t->etm_regs);
 606         t->etm_regs = NULL;
 607
 608         amba_release_regions(dev);
 609
 610         sysfs_remove_file(&dev->dev.kobj, &trace_running_attr.attr);
 611         sysfs_remove_file(&dev->dev.kobj, &trace_info_attr.attr);
 612         sysfs_remove_file(&dev->dev.kobj, &trace_mode_attr.attr);
 613
 614         return 0;
 615 }
 616
 617 static struct amba_id etm_ids[] = {
 618         {
 619                 .id     = 0x0003b921,
 620                 .mask   = 0x0007ffff,
 621         },
 622         { 0, 0 },
 623 };
 624
 625 static struct amba_driver etm_driver = {
 626         .drv            = {
 627                 .name   = "etm",
 628                 .owner  = THIS_MODULE,
 629         },
 630         .probe          = etm_probe,
 631         .remove         = etm_remove,
 632         .id_table       = etm_ids,
 633 };
 634
 635 static int __init etm_init(void)
 636 {
 637         int retval;
 638
 639         retval = amba_driver_register(&etb_driver);
 640         if (retval) {
 641                 printk(KERN_ERR "Failed to register etb\n");
 642                 return retval;
 643         }
 644
 645         retval = amba_driver_register(&etm_driver);
 646         if (retval) {
 647                 amba_driver_unregister(&etb_driver);
 648                 printk(KERN_ERR "Failed to probe etm\n");
 649                 return retval;
 650         }
 651
 652         /* not being able to install this handler is not fatal */
 653         (void)register_sysrq_key('v', &sysrq_etm_op);
 654
 655         return 0;
 656 }
 657
 658 device_initcall(etm_init);
 659