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)
 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         .llseek = no_llseek,
 318 };
 319
 320 static struct miscdevice etb_miscdev = {
 321         .name = "tracebuf",
 322         .minor = 0,
 323         .fops = &etb_fops,
 324 };
 325
 326 static int __init etb_probe(struct amba_device *dev, struct amba_id *id)
 327 {
 328         struct tracectx *t = &tracer;
 329         int ret = 0;
 330
 331         ret = amba_request_regions(dev, NULL);
 332         if (ret)
 333                 goto out;
 334
 335         t->etb_regs = ioremap_nocache(dev->res.start, resource_size(&dev->res));
 336         if (!t->etb_regs) {
 337                 ret = -ENOMEM;
 338                 goto out_release;
 339         }
 340
 341         amba_set_drvdata(dev, t);
 342
 343         etb_miscdev.parent = &dev->dev;
 344
 345         ret = misc_register(&etb_miscdev);
 346         if (ret)
 347                 goto out_unmap;
 348
 349         t->emu_clk = clk_get(&dev->dev, "emu_src_ck");
 350         if (IS_ERR(t->emu_clk)) {
 351                 dev_dbg(&dev->dev, "Failed to obtain emu_src_ck.\n");
 352                 return -EFAULT;
 353         }
 354
 355         clk_enable(t->emu_clk);
 356
 357         etb_unlock(t);
 358         t->etb_bufsz = etb_readl(t, ETBR_DEPTH);
 359         dev_dbg(&dev->dev, "Size: %x\n", t->etb_bufsz);
 360
 361         /* make sure trace capture is disabled */
 362         etb_writel(t, 0, ETBR_CTRL);
 363         etb_writel(t, 0x1000, ETBR_FORMATTERCTRL);
 364         etb_lock(t);
 365
 366         dev_dbg(&dev->dev, "ETB AMBA driver initialized.\n");
 367
 368 out:
 369         return ret;
 370
 371 out_unmap:
 372         amba_set_drvdata(dev, NULL);
 373         iounmap(t->etb_regs);
 374
 375 out_release:
 376         amba_release_regions(dev);
 377
 378         return ret;
 379 }
 380
 381 static int etb_remove(struct amba_device *dev)
 382 {
 383         struct tracectx *t = amba_get_drvdata(dev);
 384
 385         amba_set_drvdata(dev, NULL);
 386
 387         iounmap(t->etb_regs);
 388         t->etb_regs = NULL;
 389
 390         clk_disable(t->emu_clk);
 391         clk_put(t->emu_clk);
 392
 393         amba_release_regions(dev);
 394
 395         return 0;
 396 }
 397
 398 static struct amba_id etb_ids[] = {
 399         {
 400                 .id     = 0x0003b907,
 401                 .mask   = 0x0007ffff,
 402         },
 403         { 0, 0 },
 404 };
 405
 406 static struct amba_driver etb_driver = {
 407         .drv            = {
 408                 .name   = "etb",
 409                 .owner  = THIS_MODULE,
 410         },
 411         .probe          = etb_probe,
 412         .remove         = etb_remove,
 413         .id_table       = etb_ids,
 414 };
 415
 416 /* use a sysfs file "trace_running" to start/stop tracing */
 417 static ssize_t trace_running_show(struct kobject *kobj,
 418                                   struct kobj_attribute *attr,
 419                                   char *buf)
 420 {
 421         return sprintf(buf, "%x\n", trace_isrunning(&tracer));
 422 }
 423
 424 static ssize_t trace_running_store(struct kobject *kobj,
 425                                    struct kobj_attribute *attr,
 426                                    const char *buf, size_t n)
 427 {
 428         unsigned int value;
 429         int ret;
 430
 431         if (sscanf(buf, "%u", &value) != 1)
 432                 return -EINVAL;
 433
 434         mutex_lock(&tracer.mutex);
 435         ret = value ? trace_start(&tracer) : trace_stop(&tracer);
 436         mutex_unlock(&tracer.mutex);
 437
 438         return ret ? : n;
 439 }
 440
 441 static struct kobj_attribute trace_running_attr =
 442         __ATTR(trace_running, 0644, trace_running_show, trace_running_store);
 443
 444 static ssize_t trace_info_show(struct kobject *kobj,
 445                                   struct kobj_attribute *attr,
 446                                   char *buf)
 447 {
 448         u32 etb_wa, etb_ra, etb_st, etb_fc, etm_ctrl, etm_st;
 449         int datalen;
 450
 451         etb_unlock(&tracer);
 452         datalen = etb_getdatalen(&tracer);
 453         etb_wa = etb_readl(&tracer, ETBR_WRITEADDR);
 454         etb_ra = etb_readl(&tracer, ETBR_READADDR);
 455         etb_st = etb_readl(&tracer, ETBR_STATUS);
 456         etb_fc = etb_readl(&tracer, ETBR_FORMATTERCTRL);
 457         etb_lock(&tracer);
 458
 459         etm_unlock(&tracer);
 460         etm_ctrl = etm_readl(&tracer, ETMR_CTRL);
 461         etm_st = etm_readl(&tracer, ETMR_STATUS);
 462         etm_lock(&tracer);
 463
 464         return sprintf(buf, "Trace buffer len: %d\nComparator pairs: %d\n"
 465                         "ETBR_WRITEADDR:\t%08x\n"
 466                         "ETBR_READADDR:\t%08x\n"
 467                         "ETBR_STATUS:\t%08x\n"
 468                         "ETBR_FORMATTERCTRL:\t%08x\n"
 469                         "ETMR_CTRL:\t%08x\n"
 470                         "ETMR_STATUS:\t%08x\n",
 471                         datalen,
 472                         tracer.ncmppairs,
 473                         etb_wa,
 474                         etb_ra,
 475                         etb_st,
 476                         etb_fc,
 477                         etm_ctrl,
 478                         etm_st
 479                         );
 480 }
 481
 482 static struct kobj_attribute trace_info_attr =
 483         __ATTR(trace_info, 0444, trace_info_show, NULL);
 484
 485 static ssize_t trace_mode_show(struct kobject *kobj,
 486                                   struct kobj_attribute *attr,
 487                                   char *buf)
 488 {
 489         return sprintf(buf, "%d %d\n",
 490                         !!(tracer.flags & TRACER_CYCLE_ACC),
 491                         tracer.etm_portsz);
 492 }
 493
 494 static ssize_t trace_mode_store(struct kobject *kobj,
 495                                    struct kobj_attribute *attr,
 496                                    const char *buf, size_t n)
 497 {
 498         unsigned int cycacc, portsz;
 499
 500         if (sscanf(buf, "%u %u", &cycacc, &portsz) != 2)
 501                 return -EINVAL;
 502
 503         mutex_lock(&tracer.mutex);
 504         if (cycacc)
 505                 tracer.flags |= TRACER_CYCLE_ACC;
 506         else
 507                 tracer.flags &= ~TRACER_CYCLE_ACC;
 508
 509         tracer.etm_portsz = portsz & 0x0f;
 510         mutex_unlock(&tracer.mutex);
 511
 512         return n;
 513 }
 514
 515 static struct kobj_attribute trace_mode_attr =
 516         __ATTR(trace_mode, 0644, trace_mode_show, trace_mode_store);
 517
 518 static int __init etm_probe(struct amba_device *dev, struct amba_id *id)
 519 {
 520         struct tracectx *t = &tracer;
 521         int ret = 0;
 522
 523         if (t->etm_regs) {
 524                 dev_dbg(&dev->dev, "ETM already initialized\n");
 525                 ret = -EBUSY;
 526                 goto out;
 527         }
 528
 529         ret = amba_request_regions(dev, NULL);
 530         if (ret)
 531                 goto out;
 532
 533         t->etm_regs = ioremap_nocache(dev->res.start, resource_size(&dev->res));
 534         if (!t->etm_regs) {
 535                 ret = -ENOMEM;
 536                 goto out_release;
 537         }
 538
 539         amba_set_drvdata(dev, t);
 540
 541         mutex_init(&t->mutex);
 542         t->dev = &dev->dev;
 543         t->flags = TRACER_CYCLE_ACC;
 544         t->etm_portsz = 1;
 545
 546         etm_unlock(t);
 547         (void)etm_readl(t, ETMMR_PDSR);
 548         /* dummy first read */
 549         (void)etm_readl(&tracer, ETMMR_OSSRR);
 550
 551         t->ncmppairs = etm_readl(t, ETMR_CONFCODE) & 0xf;
 552         etm_writel(t, 0x440, ETMR_CTRL);
 553         etm_lock(t);
 554
 555         ret = sysfs_create_file(&dev->dev.kobj,
 556                         &trace_running_attr.attr);
 557         if (ret)
 558                 goto out_unmap;
 559
 560         /* failing to create any of these two is not fatal */
 561         ret = sysfs_create_file(&dev->dev.kobj, &trace_info_attr.attr);
 562         if (ret)
 563                 dev_dbg(&dev->dev, "Failed to create trace_info in sysfs\n");
 564
 565         ret = sysfs_create_file(&dev->dev.kobj, &trace_mode_attr.attr);
 566         if (ret)
 567                 dev_dbg(&dev->dev, "Failed to create trace_mode in sysfs\n");
 568
 569         dev_dbg(t->dev, "ETM AMBA driver initialized.\n");
 570
 571 out:
 572         return ret;
 573
 574 out_unmap:
 575         amba_set_drvdata(dev, NULL);
 576         iounmap(t->etm_regs);
 577
 578 out_release:
 579         amba_release_regions(dev);
 580
 581         return ret;
 582 }
 583
 584 static int etm_remove(struct amba_device *dev)
 585 {
 586         struct tracectx *t = amba_get_drvdata(dev);
 587
 588         amba_set_drvdata(dev, NULL);
 589
 590         iounmap(t->etm_regs);
 591         t->etm_regs = NULL;
 592
 593         amba_release_regions(dev);
 594
 595         sysfs_remove_file(&dev->dev.kobj, &trace_running_attr.attr);
 596         sysfs_remove_file(&dev->dev.kobj, &trace_info_attr.attr);
 597         sysfs_remove_file(&dev->dev.kobj, &trace_mode_attr.attr);
 598
 599         return 0;
 600 }
 601
 602 static struct amba_id etm_ids[] = {
 603         {
 604                 .id     = 0x0003b921,
 605                 .mask   = 0x0007ffff,
 606         },
 607         { 0, 0 },
 608 };
 609
 610 static struct amba_driver etm_driver = {
 611         .drv            = {
 612                 .name   = "etm",
 613                 .owner  = THIS_MODULE,
 614         },
 615         .probe          = etm_probe,
 616         .remove         = etm_remove,
 617         .id_table       = etm_ids,
 618 };
 619
 620 static int __init etm_init(void)
 621 {
 622         int retval;
 623
 624         retval = amba_driver_register(&etb_driver);
 625         if (retval) {
 626                 printk(KERN_ERR "Failed to register etb\n");
 627                 return retval;
 628         }
 629
 630         retval = amba_driver_register(&etm_driver);
 631         if (retval) {
 632                 amba_driver_unregister(&etb_driver);
 633                 printk(KERN_ERR "Failed to probe etm\n");
 634                 return retval;
 635         }
 636
 637         /* not being able to install this handler is not fatal */
 638         (void)register_sysrq_key('v', &sysrq_etm_op);
 639
 640         return 0;
 641 }
 642
 643 device_initcall(etm_init);
 644