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 <linux/module.h>
  28 #include <asm/hardware/coresight.h>
  29 #include <asm/sections.h>
  30
  31 MODULE_LICENSE("GPL");
  32 MODULE_AUTHOR("Alexander Shishkin");
  33
  34 /*
  35  * ETM tracer state
  36  */
  37 struct tracectx {
  38         unsigned int    etb_bufsz;
  39         void __iomem    *etb_regs;
  40         void __iomem    *etm_regs;
  41         unsigned long   flags;
  42         int             ncmppairs;
  43         int             etm_portsz;
  44         struct device   *dev;
  45         struct clk      *emu_clk;
  46         struct mutex    mutex;
  47 };
  48
  49 static struct tracectx tracer;
  50
  51 static inline bool trace_isrunning(struct tracectx *t)
  52 {
  53         return !!(t->flags & TRACER_RUNNING);
  54 }
  55
  56 static int etm_setup_address_range(struct tracectx *t, int n,
  57                 unsigned long start, unsigned long end, int exclude, int data)
  58 {
  59         u32 flags = ETMAAT_ARM | ETMAAT_IGNCONTEXTID | ETMAAT_NSONLY | \
  60                     ETMAAT_NOVALCMP;
  61
  62         if (n < 1 || n > t->ncmppairs)
  63                 return -EINVAL;
  64
  65         /* comparators and ranges are numbered starting with 1 as opposed
  66          * to bits in a word */
  67         n--;
  68
  69         if (data)
  70                 flags |= ETMAAT_DLOADSTORE;
  71         else
  72                 flags |= ETMAAT_IEXEC;
  73
  74         /* first comparator for the range */
  75         etm_writel(t, flags, ETMR_COMP_ACC_TYPE(n * 2));
  76         etm_writel(t, start, ETMR_COMP_VAL(n * 2));
  77
  78         /* second comparator is right next to it */
  79         etm_writel(t, flags, ETMR_COMP_ACC_TYPE(n * 2 + 1));
  80         etm_writel(t, end, ETMR_COMP_VAL(n * 2 + 1));
  81
  82         flags = exclude ? ETMTE_INCLEXCL : 0;
  83         etm_writel(t, flags | (1 << n), ETMR_TRACEENCTRL);
  84
  85         return 0;
  86 }
  87
  88 static int trace_start(struct tracectx *t)
  89 {
  90         u32 v;
  91         unsigned long timeout = TRACER_TIMEOUT;
  92
  93         etb_unlock(t);
  94
  95         etb_writel(t, 0, ETBR_FORMATTERCTRL);
  96         etb_writel(t, 1, ETBR_CTRL);
  97
  98         etb_lock(t);
  99
 100         /* configure etm */
 101         v = ETMCTRL_OPTS | ETMCTRL_PROGRAM | ETMCTRL_PORTSIZE(t->etm_portsz);
 102
 103         if (t->flags & TRACER_CYCLE_ACC)
 104                 v |= ETMCTRL_CYCLEACCURATE;
 105
 106         etm_unlock(t);
 107
 108         etm_writel(t, v, ETMR_CTRL);
 109
 110         while (!(etm_readl(t, ETMR_CTRL) & ETMCTRL_PROGRAM) && --timeout)
 111                 ;
 112         if (!timeout) {
 113                 dev_dbg(t->dev, "Waiting for progbit to assert timed out\n");
 114                 etm_lock(t);
 115                 return -EFAULT;
 116         }
 117
 118         etm_setup_address_range(t, 1, (unsigned long)_stext,
 119                         (unsigned long)_etext, 0, 0);
 120         etm_writel(t, 0, ETMR_TRACEENCTRL2);
 121         etm_writel(t, 0, ETMR_TRACESSCTRL);
 122         etm_writel(t, 0x6f, ETMR_TRACEENEVT);
 123
 124         v &= ~ETMCTRL_PROGRAM;
 125         v |= ETMCTRL_PORTSEL;
 126
 127         etm_writel(t, v, ETMR_CTRL);
 128
 129         timeout = TRACER_TIMEOUT;
 130         while (etm_readl(t, ETMR_CTRL) & ETMCTRL_PROGRAM && --timeout)
 131                 ;
 132         if (!timeout) {
 133                 dev_dbg(t->dev, "Waiting for progbit to deassert timed out\n");
 134                 etm_lock(t);
 135                 return -EFAULT;
 136         }
 137
 138         etm_lock(t);
 139
 140         t->flags |= TRACER_RUNNING;
 141
 142         return 0;
 143 }
 144
 145 static int trace_stop(struct tracectx *t)
 146 {
 147         unsigned long timeout = TRACER_TIMEOUT;
 148
 149         etm_unlock(t);
 150
 151         etm_writel(t, 0x440, ETMR_CTRL);
 152         while (!(etm_readl(t, ETMR_CTRL) & ETMCTRL_PROGRAM) && --timeout)
 153                 ;
 154         if (!timeout) {
 155                 dev_dbg(t->dev, "Waiting for progbit to assert timed out\n");
 156                 etm_lock(t);
 157                 return -EFAULT;
 158         }
 159
 160         etm_lock(t);
 161
 162         etb_unlock(t);
 163         etb_writel(t, ETBFF_MANUAL_FLUSH, ETBR_FORMATTERCTRL);
 164
 165         timeout = TRACER_TIMEOUT;
 166         while (etb_readl(t, ETBR_FORMATTERCTRL) &
 167                         ETBFF_MANUAL_FLUSH && --timeout)
 168                 ;
 169         if (!timeout) {
 170                 dev_dbg(t->dev, "Waiting for formatter flush to commence "
 171                                 "timed out\n");
 172                 etb_lock(t);
 173                 return -EFAULT;
 174         }
 175
 176         etb_writel(t, 0, ETBR_CTRL);
 177
 178         etb_lock(t);
 179
 180         t->flags &= ~TRACER_RUNNING;
 181
 182         return 0;
 183 }
 184
 185 static int etb_getdatalen(struct tracectx *t)
 186 {
 187         u32 v;
 188         int rp, wp;
 189
 190         v = etb_readl(t, ETBR_STATUS);
 191
 192         if (v & 1)
 193                 return t->etb_bufsz;
 194
 195         rp = etb_readl(t, ETBR_READADDR);
 196         wp = etb_readl(t, ETBR_WRITEADDR);
 197
 198         if (rp > wp) {
 199                 etb_writel(t, 0, ETBR_READADDR);
 200                 etb_writel(t, 0, ETBR_WRITEADDR);
 201
 202                 return 0;
 203         }
 204
 205         return wp - rp;
 206 }
 207
 208 /* sysrq+v will always stop the running trace and leave it at that */
 209 static void etm_dump(void)
 210 {
 211         struct tracectx *t = &tracer;
 212         u32 first = 0;
 213         int length;
 214
 215         if (!t->etb_regs) {
 216                 printk(KERN_INFO "No tracing hardware found\n");
 217                 return;
 218         }
 219
 220         if (trace_isrunning(t))
 221                 trace_stop(t);
 222
 223         etb_unlock(t);
 224
 225         length = etb_getdatalen(t);
 226
 227         if (length == t->etb_bufsz)
 228                 first = etb_readl(t, ETBR_WRITEADDR);
 229
 230         etb_writel(t, first, ETBR_READADDR);
 231
 232         printk(KERN_INFO "Trace buffer contents length: %d\n", length);
 233         printk(KERN_INFO "--- ETB buffer begin ---\n");
 234         for (; length; length--)
 235                 printk("%08x", cpu_to_be32(etb_readl(t, ETBR_READMEM)));
 236         printk(KERN_INFO "\n--- ETB buffer end ---\n");
 237
 238         /* deassert the overflow bit */
 239         etb_writel(t, 1, ETBR_CTRL);
 240         etb_writel(t, 0, ETBR_CTRL);
 241
 242         etb_writel(t, 0, ETBR_TRIGGERCOUNT);
 243         etb_writel(t, 0, ETBR_READADDR);
 244         etb_writel(t, 0, ETBR_WRITEADDR);
 245
 246         etb_lock(t);
 247 }
 248
 249 static void sysrq_etm_dump(int key)
 250 {
 251         dev_dbg(tracer.dev, "Dumping ETB buffer\n");
 252         etm_dump();
 253 }
 254
 255 static struct sysrq_key_op sysrq_etm_op = {
 256         .handler = sysrq_etm_dump,
 257         .help_msg = "etm-buffer-dump(v)",
 258         .action_msg = "etm",
 259 };
 260
 261 static int etb_open(struct inode *inode, struct file *file)
 262 {
 263         if (!tracer.etb_regs)
 264                 return -ENODEV;
 265
 266         file->private_data = &tracer;
 267
 268         return nonseekable_open(inode, file);
 269 }
 270
 271 static ssize_t etb_read(struct file *file, char __user *data,
 272                 size_t len, loff_t *ppos)
 273 {
 274         int total, i;
 275         long length;
 276         struct tracectx *t = file->private_data;
 277         u32 first = 0;
 278         u32 *buf;
 279
 280         mutex_lock(&t->mutex);
 281
 282         if (trace_isrunning(t)) {
 283                 length = 0;
 284                 goto out;
 285         }
 286
 287         etb_unlock(t);
 288
 289         total = etb_getdatalen(t);
 290         if (total == t->etb_bufsz)
 291                 first = etb_readl(t, ETBR_WRITEADDR);
 292
 293         etb_writel(t, first, ETBR_READADDR);
 294
 295         length = min(total * 4, (int)len);
 296         buf = vmalloc(length);
 297
 298         dev_dbg(t->dev, "ETB buffer length: %d\n", total);
 299         dev_dbg(t->dev, "ETB status reg: %x\n", etb_readl(t, ETBR_STATUS));
 300         for (i = 0; i < length / 4; i++)
 301                 buf[i] = etb_readl(t, ETBR_READMEM);
 302
 303         /* the only way to deassert overflow bit in ETB status is this */
 304         etb_writel(t, 1, ETBR_CTRL);
 305         etb_writel(t, 0, ETBR_CTRL);
 306
 307         etb_writel(t, 0, ETBR_WRITEADDR);
 308         etb_writel(t, 0, ETBR_READADDR);
 309         etb_writel(t, 0, ETBR_TRIGGERCOUNT);
 310
 311         etb_lock(t);
 312
 313         length -= copy_to_user(data, buf, length);
 314         vfree(buf);
 315
 316 out:
 317         mutex_unlock(&t->mutex);
 318
 319         return length;
 320 }
 321
 322 static int etb_release(struct inode *inode, struct file *file)
 323 {
 324         /* there's nothing to do here, actually */
 325         return 0;
 326 }
 327
 328 static const struct file_operations etb_fops = {
 329         .owner = THIS_MODULE,
 330         .read = etb_read,
 331         .open = etb_open,
 332         .release = etb_release,
 333         .llseek = no_llseek,
 334 };
 335
 336 static struct miscdevice etb_miscdev = {
 337         .name = "tracebuf",
 338         .minor = 0,
 339         .fops = &etb_fops,
 340 };
 341
 342 static int etb_probe(struct amba_device *dev, const struct amba_id *id)
 343 {
 344         struct tracectx *t = &tracer;
 345         int ret = 0;
 346
 347         ret = amba_request_regions(dev, NULL);
 348         if (ret)
 349                 goto out;
 350
 351         t->etb_regs = ioremap_nocache(dev->res.start, resource_size(&dev->res));
 352         if (!t->etb_regs) {
 353                 ret = -ENOMEM;
 354                 goto out_release;
 355         }
 356
 357         amba_set_drvdata(dev, t);
 358
 359         etb_miscdev.parent = &dev->dev;
 360
 361         ret = misc_register(&etb_miscdev);
 362         if (ret)
 363                 goto out_unmap;
 364
 365         t->emu_clk = clk_get(&dev->dev, "emu_src_ck");
 366         if (IS_ERR(t->emu_clk)) {
 367                 dev_dbg(&dev->dev, "Failed to obtain emu_src_ck.\n");
 368                 return -EFAULT;
 369         }
 370
 371         clk_enable(t->emu_clk);
 372
 373         etb_unlock(t);
 374         t->etb_bufsz = etb_readl(t, ETBR_DEPTH);
 375         dev_dbg(&dev->dev, "Size: %x\n", t->etb_bufsz);
 376
 377         /* make sure trace capture is disabled */
 378         etb_writel(t, 0, ETBR_CTRL);
 379         etb_writel(t, 0x1000, ETBR_FORMATTERCTRL);
 380         etb_lock(t);
 381
 382         dev_dbg(&dev->dev, "ETB AMBA driver initialized.\n");
 383
 384 out:
 385         return ret;
 386
 387 out_unmap:
 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         iounmap(t->etb_regs);
 401         t->etb_regs = NULL;
 402
 403         clk_disable(t->emu_clk);
 404         clk_put(t->emu_clk);
 405
 406         amba_release_regions(dev);
 407
 408         return 0;
 409 }
 410
 411 static struct amba_id etb_ids[] = {
 412         {
 413                 .id     = 0x0003b907,
 414                 .mask   = 0x0007ffff,
 415         },
 416         { 0, 0 },
 417 };
 418
 419 static struct amba_driver etb_driver = {
 420         .drv            = {
 421                 .name   = "etb",
 422                 .owner  = THIS_MODULE,
 423         },
 424         .probe          = etb_probe,
 425         .remove         = etb_remove,
 426         .id_table       = etb_ids,
 427 };
 428
 429 /* use a sysfs file "trace_running" to start/stop tracing */
 430 static ssize_t trace_running_show(struct kobject *kobj,
 431                                   struct kobj_attribute *attr,
 432                                   char *buf)
 433 {
 434         return sprintf(buf, "%x\n", trace_isrunning(&tracer));
 435 }
 436
 437 static ssize_t trace_running_store(struct kobject *kobj,
 438                                    struct kobj_attribute *attr,
 439                                    const char *buf, size_t n)
 440 {
 441         unsigned int value;
 442         int ret;
 443
 444         if (sscanf(buf, "%u", &value) != 1)
 445                 return -EINVAL;
 446
 447         mutex_lock(&tracer.mutex);
 448         ret = value ? trace_start(&tracer) : trace_stop(&tracer);
 449         mutex_unlock(&tracer.mutex);
 450
 451         return ret ? : n;
 452 }
 453
 454 static struct kobj_attribute trace_running_attr =
 455         __ATTR(trace_running, 0644, trace_running_show, trace_running_store);
 456
 457 static ssize_t trace_info_show(struct kobject *kobj,
 458                                   struct kobj_attribute *attr,
 459                                   char *buf)
 460 {
 461         u32 etb_wa, etb_ra, etb_st, etb_fc, etm_ctrl, etm_st;
 462         int datalen;
 463
 464         etb_unlock(&tracer);
 465         datalen = etb_getdatalen(&tracer);
 466         etb_wa = etb_readl(&tracer, ETBR_WRITEADDR);
 467         etb_ra = etb_readl(&tracer, ETBR_READADDR);
 468         etb_st = etb_readl(&tracer, ETBR_STATUS);
 469         etb_fc = etb_readl(&tracer, ETBR_FORMATTERCTRL);
 470         etb_lock(&tracer);
 471
 472         etm_unlock(&tracer);
 473         etm_ctrl = etm_readl(&tracer, ETMR_CTRL);
 474         etm_st = etm_readl(&tracer, ETMR_STATUS);
 475         etm_lock(&tracer);
 476
 477         return sprintf(buf, "Trace buffer len: %d\nComparator pairs: %d\n"
 478                         "ETBR_WRITEADDR:\t%08x\n"
 479                         "ETBR_READADDR:\t%08x\n"
 480                         "ETBR_STATUS:\t%08x\n"
 481                         "ETBR_FORMATTERCTRL:\t%08x\n"
 482                         "ETMR_CTRL:\t%08x\n"
 483                         "ETMR_STATUS:\t%08x\n",
 484                         datalen,
 485                         tracer.ncmppairs,
 486                         etb_wa,
 487                         etb_ra,
 488                         etb_st,
 489                         etb_fc,
 490                         etm_ctrl,
 491                         etm_st
 492                         );
 493 }
 494
 495 static struct kobj_attribute trace_info_attr =
 496         __ATTR(trace_info, 0444, trace_info_show, NULL);
 497
 498 static ssize_t trace_mode_show(struct kobject *kobj,
 499                                   struct kobj_attribute *attr,
 500                                   char *buf)
 501 {
 502         return sprintf(buf, "%d %d\n",
 503                         !!(tracer.flags & TRACER_CYCLE_ACC),
 504                         tracer.etm_portsz);
 505 }
 506
 507 static ssize_t trace_mode_store(struct kobject *kobj,
 508                                    struct kobj_attribute *attr,
 509                                    const char *buf, size_t n)
 510 {
 511         unsigned int cycacc, portsz;
 512
 513         if (sscanf(buf, "%u %u", &cycacc, &portsz) != 2)
 514                 return -EINVAL;
 515
 516         mutex_lock(&tracer.mutex);
 517         if (cycacc)
 518                 tracer.flags |= TRACER_CYCLE_ACC;
 519         else
 520                 tracer.flags &= ~TRACER_CYCLE_ACC;
 521
 522         tracer.etm_portsz = portsz & 0x0f;
 523         mutex_unlock(&tracer.mutex);
 524
 525         return n;
 526 }
 527
 528 static struct kobj_attribute trace_mode_attr =
 529         __ATTR(trace_mode, 0644, trace_mode_show, trace_mode_store);
 530
 531 static int etm_probe(struct amba_device *dev, const struct amba_id *id)
 532 {
 533         struct tracectx *t = &tracer;
 534         int ret = 0;
 535
 536         if (t->etm_regs) {
 537                 dev_dbg(&dev->dev, "ETM already initialized\n");
 538                 ret = -EBUSY;
 539                 goto out;
 540         }
 541
 542         ret = amba_request_regions(dev, NULL);
 543         if (ret)
 544                 goto out;
 545
 546         t->etm_regs = ioremap_nocache(dev->res.start, resource_size(&dev->res));
 547         if (!t->etm_regs) {
 548                 ret = -ENOMEM;
 549                 goto out_release;
 550         }
 551
 552         amba_set_drvdata(dev, t);
 553
 554         mutex_init(&t->mutex);
 555         t->dev = &dev->dev;
 556         t->flags = TRACER_CYCLE_ACC;
 557         t->etm_portsz = 1;
 558
 559         etm_unlock(t);
 560         (void)etm_readl(t, ETMMR_PDSR);
 561         /* dummy first read */
 562         (void)etm_readl(&tracer, ETMMR_OSSRR);
 563
 564         t->ncmppairs = etm_readl(t, ETMR_CONFCODE) & 0xf;
 565         etm_writel(t, 0x440, ETMR_CTRL);
 566         etm_lock(t);
 567
 568         ret = sysfs_create_file(&dev->dev.kobj,
 569                         &trace_running_attr.attr);
 570         if (ret)
 571                 goto out_unmap;
 572
 573         /* failing to create any of these two is not fatal */
 574         ret = sysfs_create_file(&dev->dev.kobj, &trace_info_attr.attr);
 575         if (ret)
 576                 dev_dbg(&dev->dev, "Failed to create trace_info in sysfs\n");
 577
 578         ret = sysfs_create_file(&dev->dev.kobj, &trace_mode_attr.attr);
 579         if (ret)
 580                 dev_dbg(&dev->dev, "Failed to create trace_mode in sysfs\n");
 581
 582         dev_dbg(t->dev, "ETM AMBA driver initialized.\n");
 583
 584 out:
 585         return ret;
 586
 587 out_unmap:
 588         iounmap(t->etm_regs);
 589
 590 out_release:
 591         amba_release_regions(dev);
 592
 593         return ret;
 594 }
 595
 596 static int etm_remove(struct amba_device *dev)
 597 {
 598         struct tracectx *t = amba_get_drvdata(dev);
 599
 600         iounmap(t->etm_regs);
 601         t->etm_regs = NULL;
 602
 603         amba_release_regions(dev);
 604
 605         sysfs_remove_file(&dev->dev.kobj, &trace_running_attr.attr);
 606         sysfs_remove_file(&dev->dev.kobj, &trace_info_attr.attr);
 607         sysfs_remove_file(&dev->dev.kobj, &trace_mode_attr.attr);
 608
 609         return 0;
 610 }
 611
 612 static struct amba_id etm_ids[] = {
 613         {
 614                 .id     = 0x0003b921,
 615                 .mask   = 0x0007ffff,
 616         },
 617         { 0, 0 },
 618 };
 619
 620 static struct amba_driver etm_driver = {
 621         .drv            = {
 622                 .name   = "etm",
 623                 .owner  = THIS_MODULE,
 624         },
 625         .probe          = etm_probe,
 626         .remove         = etm_remove,
 627         .id_table       = etm_ids,
 628 };
 629
 630 static int __init etm_init(void)
 631 {
 632         int retval;
 633
 634         retval = amba_driver_register(&etb_driver);
 635         if (retval) {
 636                 printk(KERN_ERR "Failed to register etb\n");
 637                 return retval;
 638         }
 639
 640         retval = amba_driver_register(&etm_driver);
 641         if (retval) {
 642                 amba_driver_unregister(&etb_driver);
 643                 printk(KERN_ERR "Failed to probe etm\n");
 644                 return retval;
 645         }
 646
 647         /* not being able to install this handler is not fatal */
 648         (void)register_sysrq_key('v', &sysrq_etm_op);
 649
 650         return 0;
 651 }
 652
 653 device_initcall(etm_init);
 654