drivers/hwtracing/coresight/coresight-tmc-core.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /* Copyright (c) 2012, The Linux Foundation. All rights reserved.
   3  *
   4  * Description: CoreSight Trace Memory Controller driver
   5  */
   6
   7 #include <linux/kernel.h>
   8 #include <linux/init.h>
   9 #include <linux/types.h>
  10 #include <linux/device.h>
  11 #include <linux/idr.h>
  12 #include <linux/io.h>
  13 #include <linux/err.h>
  14 #include <linux/fs.h>
  15 #include <linux/miscdevice.h>
  16 #include <linux/mutex.h>
  17 #include <linux/property.h>
  18 #include <linux/uaccess.h>
  19 #include <linux/slab.h>
  20 #include <linux/dma-mapping.h>
  21 #include <linux/spinlock.h>
  22 #include <linux/pm_runtime.h>
  23 #include <linux/of.h>
  24 #include <linux/coresight.h>
  25 #include <linux/amba/bus.h>
  26
  27 #include "coresight-priv.h"
  28 #include "coresight-tmc.h"
  29
  30 DEFINE_CORESIGHT_DEVLIST(etb_devs, "tmc_etb");
  31 DEFINE_CORESIGHT_DEVLIST(etf_devs, "tmc_etf");
  32 DEFINE_CORESIGHT_DEVLIST(etr_devs, "tmc_etr");
  33
  34 void tmc_wait_for_tmcready(struct tmc_drvdata *drvdata)
  35 {
  36         struct coresight_device *csdev = drvdata->csdev;
  37         struct csdev_access *csa = &csdev->access;
  38
  39         /* Ensure formatter, unformatter and hardware fifo are empty */
  40         if (coresight_timeout(csa, TMC_STS, TMC_STS_TMCREADY_BIT, 1)) {
  41                 dev_err(&csdev->dev,
  42                         "timeout while waiting for TMC to be Ready\n");
  43         }
  44 }
  45
  46 void tmc_flush_and_stop(struct tmc_drvdata *drvdata)
  47 {
  48         struct coresight_device *csdev = drvdata->csdev;
  49         struct csdev_access *csa = &csdev->access;
  50         u32 ffcr;
  51
  52         ffcr = readl_relaxed(drvdata->base + TMC_FFCR);
  53         ffcr |= TMC_FFCR_STOP_ON_FLUSH;
  54         writel_relaxed(ffcr, drvdata->base + TMC_FFCR);
  55         ffcr |= BIT(TMC_FFCR_FLUSHMAN_BIT);
  56         writel_relaxed(ffcr, drvdata->base + TMC_FFCR);
  57         /* Ensure flush completes */
  58         if (coresight_timeout(csa, TMC_FFCR, TMC_FFCR_FLUSHMAN_BIT, 0)) {
  59                 dev_err(&csdev->dev,
  60                 "timeout while waiting for completion of Manual Flush\n");
  61         }
  62
  63         tmc_wait_for_tmcready(drvdata);
  64 }
  65
  66 void tmc_enable_hw(struct tmc_drvdata *drvdata)
  67 {
  68         writel_relaxed(TMC_CTL_CAPT_EN, drvdata->base + TMC_CTL);
  69 }
  70
  71 void tmc_disable_hw(struct tmc_drvdata *drvdata)
  72 {
  73         writel_relaxed(0x0, drvdata->base + TMC_CTL);
  74 }
  75
  76 u32 tmc_get_memwidth_mask(struct tmc_drvdata *drvdata)
  77 {
  78         u32 mask = 0;
  79
  80         /*
  81          * When moving RRP or an offset address forward, the new values must
  82          * be byte-address aligned to the width of the trace memory databus
  83          * _and_ to a frame boundary (16 byte), whichever is the biggest. For
  84          * example, for 32-bit, 64-bit and 128-bit wide trace memory, the four
  85          * LSBs must be 0s. For 256-bit wide trace memory, the five LSBs must
  86          * be 0s.
  87          */
  88         switch (drvdata->memwidth) {
  89         case TMC_MEM_INTF_WIDTH_32BITS:
  90         case TMC_MEM_INTF_WIDTH_64BITS:
  91         case TMC_MEM_INTF_WIDTH_128BITS:
  92                 mask = GENMASK(31, 4);
  93                 break;
  94         case TMC_MEM_INTF_WIDTH_256BITS:
  95                 mask = GENMASK(31, 5);
  96                 break;
  97         }
  98
  99         return mask;
 100 }
 101
 102 static int tmc_read_prepare(struct tmc_drvdata *drvdata)
 103 {
 104         int ret = 0;
 105
 106         switch (drvdata->config_type) {
 107         case TMC_CONFIG_TYPE_ETB:
 108         case TMC_CONFIG_TYPE_ETF:
 109                 ret = tmc_read_prepare_etb(drvdata);
 110                 break;
 111         case TMC_CONFIG_TYPE_ETR:
 112                 ret = tmc_read_prepare_etr(drvdata);
 113                 break;
 114         default:
 115                 ret = -EINVAL;
 116         }
 117
 118         if (!ret)
 119                 dev_dbg(&drvdata->csdev->dev, "TMC read start\n");
 120
 121         return ret;
 122 }
 123
 124 static int tmc_read_unprepare(struct tmc_drvdata *drvdata)
 125 {
 126         int ret = 0;
 127
 128         switch (drvdata->config_type) {
 129         case TMC_CONFIG_TYPE_ETB:
 130         case TMC_CONFIG_TYPE_ETF:
 131                 ret = tmc_read_unprepare_etb(drvdata);
 132                 break;
 133         case TMC_CONFIG_TYPE_ETR:
 134                 ret = tmc_read_unprepare_etr(drvdata);
 135                 break;
 136         default:
 137                 ret = -EINVAL;
 138         }
 139
 140         if (!ret)
 141                 dev_dbg(&drvdata->csdev->dev, "TMC read end\n");
 142
 143         return ret;
 144 }
 145
 146 static int tmc_open(struct inode *inode, struct file *file)
 147 {
 148         int ret;
 149         struct tmc_drvdata *drvdata = container_of(file->private_data,
 150                                                    struct tmc_drvdata, miscdev);
 151
 152         ret = tmc_read_prepare(drvdata);
 153         if (ret)
 154                 return ret;
 155
 156         nonseekable_open(inode, file);
 157
 158         dev_dbg(&drvdata->csdev->dev, "%s: successfully opened\n", __func__);
 159         return 0;
 160 }
 161
 162 static inline ssize_t tmc_get_sysfs_trace(struct tmc_drvdata *drvdata,
 163                                           loff_t pos, size_t len, char **bufpp)
 164 {
 165         switch (drvdata->config_type) {
 166         case TMC_CONFIG_TYPE_ETB:
 167         case TMC_CONFIG_TYPE_ETF:
 168                 return tmc_etb_get_sysfs_trace(drvdata, pos, len, bufpp);
 169         case TMC_CONFIG_TYPE_ETR:
 170                 return tmc_etr_get_sysfs_trace(drvdata, pos, len, bufpp);
 171         }
 172
 173         return -EINVAL;
 174 }
 175
 176 static ssize_t tmc_read(struct file *file, char __user *data, size_t len,
 177                         loff_t *ppos)
 178 {
 179         char *bufp;
 180         ssize_t actual;
 181         struct tmc_drvdata *drvdata = container_of(file->private_data,
 182                                                    struct tmc_drvdata, miscdev);
 183         actual = tmc_get_sysfs_trace(drvdata, *ppos, len, &bufp);
 184         if (actual <= 0)
 185                 return 0;
 186
 187         if (copy_to_user(data, bufp, actual)) {
 188                 dev_dbg(&drvdata->csdev->dev,
 189                         "%s: copy_to_user failed\n", __func__);
 190                 return -EFAULT;
 191         }
 192
 193         *ppos += actual;
 194         dev_dbg(&drvdata->csdev->dev, "%zu bytes copied\n", actual);
 195
 196         return actual;
 197 }
 198
 199 static int tmc_release(struct inode *inode, struct file *file)
 200 {
 201         int ret;
 202         struct tmc_drvdata *drvdata = container_of(file->private_data,
 203                                                    struct tmc_drvdata, miscdev);
 204
 205         ret = tmc_read_unprepare(drvdata);
 206         if (ret)
 207                 return ret;
 208
 209         dev_dbg(&drvdata->csdev->dev, "%s: released\n", __func__);
 210         return 0;
 211 }
 212
 213 static const struct file_operations tmc_fops = {
 214         .owner          = THIS_MODULE,
 215         .open           = tmc_open,
 216         .read           = tmc_read,
 217         .release        = tmc_release,
 218         .llseek         = no_llseek,
 219 };
 220
 221 static enum tmc_mem_intf_width tmc_get_memwidth(u32 devid)
 222 {
 223         enum tmc_mem_intf_width memwidth;
 224
 225         /*
 226          * Excerpt from the TRM:
 227          *
 228          * DEVID::MEMWIDTH[10:8]
 229          * 0x2 Memory interface databus is 32 bits wide.
 230          * 0x3 Memory interface databus is 64 bits wide.
 231          * 0x4 Memory interface databus is 128 bits wide.
 232          * 0x5 Memory interface databus is 256 bits wide.
 233          */
 234         switch (BMVAL(devid, 8, 10)) {
 235         case 0x2:
 236                 memwidth = TMC_MEM_INTF_WIDTH_32BITS;
 237                 break;
 238         case 0x3:
 239                 memwidth = TMC_MEM_INTF_WIDTH_64BITS;
 240                 break;
 241         case 0x4:
 242                 memwidth = TMC_MEM_INTF_WIDTH_128BITS;
 243                 break;
 244         case 0x5:
 245                 memwidth = TMC_MEM_INTF_WIDTH_256BITS;
 246                 break;
 247         default:
 248                 memwidth = 0;
 249         }
 250
 251         return memwidth;
 252 }
 253
 254 #define coresight_tmc_reg(name, offset)                 \
 255         coresight_simple_reg32(struct tmc_drvdata, name, offset)
 256 #define coresight_tmc_reg64(name, lo_off, hi_off)       \
 257         coresight_simple_reg64(struct tmc_drvdata, name, lo_off, hi_off)
 258
 259 coresight_tmc_reg(rsz, TMC_RSZ);
 260 coresight_tmc_reg(sts, TMC_STS);
 261 coresight_tmc_reg(trg, TMC_TRG);
 262 coresight_tmc_reg(ctl, TMC_CTL);
 263 coresight_tmc_reg(ffsr, TMC_FFSR);
 264 coresight_tmc_reg(ffcr, TMC_FFCR);
 265 coresight_tmc_reg(mode, TMC_MODE);
 266 coresight_tmc_reg(pscr, TMC_PSCR);
 267 coresight_tmc_reg(axictl, TMC_AXICTL);
 268 coresight_tmc_reg(authstatus, TMC_AUTHSTATUS);
 269 coresight_tmc_reg(devid, CORESIGHT_DEVID);
 270 coresight_tmc_reg64(rrp, TMC_RRP, TMC_RRPHI);
 271 coresight_tmc_reg64(rwp, TMC_RWP, TMC_RWPHI);
 272 coresight_tmc_reg64(dba, TMC_DBALO, TMC_DBAHI);
 273
 274 static struct attribute *coresight_tmc_mgmt_attrs[] = {
 275         &dev_attr_rsz.attr,
 276         &dev_attr_sts.attr,
 277         &dev_attr_rrp.attr,
 278         &dev_attr_rwp.attr,
 279         &dev_attr_trg.attr,
 280         &dev_attr_ctl.attr,
 281         &dev_attr_ffsr.attr,
 282         &dev_attr_ffcr.attr,
 283         &dev_attr_mode.attr,
 284         &dev_attr_pscr.attr,
 285         &dev_attr_devid.attr,
 286         &dev_attr_dba.attr,
 287         &dev_attr_axictl.attr,
 288         &dev_attr_authstatus.attr,
 289         NULL,
 290 };
 291
 292 static ssize_t trigger_cntr_show(struct device *dev,
 293                                  struct device_attribute *attr, char *buf)
 294 {
 295         struct tmc_drvdata *drvdata = dev_get_drvdata(dev->parent);
 296         unsigned long val = drvdata->trigger_cntr;
 297
 298         return sprintf(buf, "%#lx\n", val);
 299 }
 300
 301 static ssize_t trigger_cntr_store(struct device *dev,
 302                              struct device_attribute *attr,
 303                              const char *buf, size_t size)
 304 {
 305         int ret;
 306         unsigned long val;
 307         struct tmc_drvdata *drvdata = dev_get_drvdata(dev->parent);
 308
 309         ret = kstrtoul(buf, 16, &val);
 310         if (ret)
 311                 return ret;
 312
 313         drvdata->trigger_cntr = val;
 314         return size;
 315 }
 316 static DEVICE_ATTR_RW(trigger_cntr);
 317
 318 static ssize_t buffer_size_show(struct device *dev,
 319                                 struct device_attribute *attr, char *buf)
 320 {
 321         struct tmc_drvdata *drvdata = dev_get_drvdata(dev->parent);
 322
 323         return sprintf(buf, "%#x\n", drvdata->size);
 324 }
 325
 326 static ssize_t buffer_size_store(struct device *dev,
 327                                  struct device_attribute *attr,
 328                                  const char *buf, size_t size)
 329 {
 330         int ret;
 331         unsigned long val;
 332         struct tmc_drvdata *drvdata = dev_get_drvdata(dev->parent);
 333
 334         /* Only permitted for TMC-ETRs */
 335         if (drvdata->config_type != TMC_CONFIG_TYPE_ETR)
 336                 return -EPERM;
 337
 338         ret = kstrtoul(buf, 0, &val);
 339         if (ret)
 340                 return ret;
 341         /* The buffer size should be page aligned */
 342         if (val & (PAGE_SIZE - 1))
 343                 return -EINVAL;
 344         drvdata->size = val;
 345         return size;
 346 }
 347
 348 static DEVICE_ATTR_RW(buffer_size);
 349
 350 static struct attribute *coresight_tmc_attrs[] = {
 351         &dev_attr_trigger_cntr.attr,
 352         &dev_attr_buffer_size.attr,
 353         NULL,
 354 };
 355
 356 static const struct attribute_group coresight_tmc_group = {
 357         .attrs = coresight_tmc_attrs,
 358 };
 359
 360 static const struct attribute_group coresight_tmc_mgmt_group = {
 361         .attrs = coresight_tmc_mgmt_attrs,
 362         .name = "mgmt",
 363 };
 364
 365 static const struct attribute_group *coresight_tmc_groups[] = {
 366         &coresight_tmc_group,
 367         &coresight_tmc_mgmt_group,
 368         NULL,
 369 };
 370
 371 static inline bool tmc_etr_can_use_sg(struct device *dev)
 372 {
 373         return fwnode_property_present(dev->fwnode, "arm,scatter-gather");
 374 }
 375
 376 static inline bool tmc_etr_has_non_secure_access(struct tmc_drvdata *drvdata)
 377 {
 378         u32 auth = readl_relaxed(drvdata->base + TMC_AUTHSTATUS);
 379
 380         return (auth & TMC_AUTH_NSID_MASK) == 0x3;
 381 }
 382
 383 /* Detect and initialise the capabilities of a TMC ETR */
 384 static int tmc_etr_setup_caps(struct device *parent, u32 devid, void *dev_caps)
 385 {
 386         int rc;
 387         u32 dma_mask = 0;
 388         struct tmc_drvdata *drvdata = dev_get_drvdata(parent);
 389
 390         if (!tmc_etr_has_non_secure_access(drvdata))
 391                 return -EACCES;
 392
 393         /* Set the unadvertised capabilities */
 394         tmc_etr_init_caps(drvdata, (u32)(unsigned long)dev_caps);
 395
 396         if (!(devid & TMC_DEVID_NOSCAT) && tmc_etr_can_use_sg(parent))
 397                 tmc_etr_set_cap(drvdata, TMC_ETR_SG);
 398
 399         /* Check if the AXI address width is available */
 400         if (devid & TMC_DEVID_AXIAW_VALID)
 401                 dma_mask = ((devid >> TMC_DEVID_AXIAW_SHIFT) &
 402                                 TMC_DEVID_AXIAW_MASK);
 403
 404         /*
 405          * Unless specified in the device configuration, ETR uses a 40-bit
 406          * AXI master in place of the embedded SRAM of ETB/ETF.
 407          */
 408         switch (dma_mask) {
 409         case 32:
 410         case 40:
 411         case 44:
 412         case 48:
 413         case 52:
 414                 dev_info(parent, "Detected dma mask %dbits\n", dma_mask);
 415                 break;
 416         default:
 417                 dma_mask = 40;
 418         }
 419
 420         rc = dma_set_mask_and_coherent(parent, DMA_BIT_MASK(dma_mask));
 421         if (rc)
 422                 dev_err(parent, "Failed to setup DMA mask: %d\n", rc);
 423         return rc;
 424 }
 425
 426 static u32 tmc_etr_get_default_buffer_size(struct device *dev)
 427 {
 428         u32 size;
 429
 430         if (fwnode_property_read_u32(dev->fwnode, "arm,buffer-size", &size))
 431                 size = SZ_1M;
 432         return size;
 433 }
 434
 435 static u32 tmc_etr_get_max_burst_size(struct device *dev)
 436 {
 437         u32 burst_size;
 438
 439         if (fwnode_property_read_u32(dev->fwnode, "arm,max-burst-size",
 440                                      &burst_size))
 441                 return TMC_AXICTL_WR_BURST_16;
 442
 443         /* Only permissible values are 0 to 15 */
 444         if (burst_size > 0xF)
 445                 burst_size = TMC_AXICTL_WR_BURST_16;
 446
 447         return burst_size;
 448 }
 449
 450 static int tmc_probe(struct amba_device *adev, const struct amba_id *id)
 451 {
 452         int ret = 0;
 453         u32 devid;
 454         void __iomem *base;
 455         struct device *dev = &adev->dev;
 456         struct coresight_platform_data *pdata = NULL;
 457         struct tmc_drvdata *drvdata;
 458         struct resource *res = &adev->res;
 459         struct coresight_desc desc = { 0 };
 460         struct coresight_dev_list *dev_list = NULL;
 461
 462         ret = -ENOMEM;
 463         drvdata = devm_kzalloc(dev, sizeof(*drvdata), GFP_KERNEL);
 464         if (!drvdata)
 465                 goto out;
 466
 467         dev_set_drvdata(dev, drvdata);
 468
 469         /* Validity for the resource is already checked by the AMBA core */
 470         base = devm_ioremap_resource(dev, res);
 471         if (IS_ERR(base)) {
 472                 ret = PTR_ERR(base);
 473                 goto out;
 474         }
 475
 476         drvdata->base = base;
 477         desc.access = CSDEV_ACCESS_IOMEM(base);
 478
 479         spin_lock_init(&drvdata->spinlock);
 480
 481         devid = readl_relaxed(drvdata->base + CORESIGHT_DEVID);
 482         drvdata->config_type = BMVAL(devid, 6, 7);
 483         drvdata->memwidth = tmc_get_memwidth(devid);
 484         /* This device is not associated with a session */
 485         drvdata->pid = -1;
 486
 487         if (drvdata->config_type == TMC_CONFIG_TYPE_ETR) {
 488                 drvdata->size = tmc_etr_get_default_buffer_size(dev);
 489                 drvdata->max_burst_size = tmc_etr_get_max_burst_size(dev);
 490         } else {
 491                 drvdata->size = readl_relaxed(drvdata->base + TMC_RSZ) * 4;
 492         }
 493
 494         desc.dev = dev;
 495         desc.groups = coresight_tmc_groups;
 496
 497         switch (drvdata->config_type) {
 498         case TMC_CONFIG_TYPE_ETB:
 499                 desc.type = CORESIGHT_DEV_TYPE_SINK;
 500                 desc.subtype.sink_subtype = CORESIGHT_DEV_SUBTYPE_SINK_BUFFER;
 501                 desc.ops = &tmc_etb_cs_ops;
 502                 dev_list = &etb_devs;
 503                 break;
 504         case TMC_CONFIG_TYPE_ETR:
 505                 desc.type = CORESIGHT_DEV_TYPE_SINK;
 506                 desc.subtype.sink_subtype = CORESIGHT_DEV_SUBTYPE_SINK_SYSMEM;
 507                 desc.ops = &tmc_etr_cs_ops;
 508                 ret = tmc_etr_setup_caps(dev, devid,
 509                                          coresight_get_uci_data(id));
 510                 if (ret)
 511                         goto out;
 512                 idr_init(&drvdata->idr);
 513                 mutex_init(&drvdata->idr_mutex);
 514                 dev_list = &etr_devs;
 515                 break;
 516         case TMC_CONFIG_TYPE_ETF:
 517                 desc.type = CORESIGHT_DEV_TYPE_LINKSINK;
 518                 desc.subtype.sink_subtype = CORESIGHT_DEV_SUBTYPE_SINK_BUFFER;
 519                 desc.subtype.link_subtype = CORESIGHT_DEV_SUBTYPE_LINK_FIFO;
 520                 desc.ops = &tmc_etf_cs_ops;
 521                 dev_list = &etf_devs;
 522                 break;
 523         default:
 524                 pr_err("%s: Unsupported TMC config\n", desc.name);
 525                 ret = -EINVAL;
 526                 goto out;
 527         }
 528
 529         desc.name = coresight_alloc_device_name(dev_list, dev);
 530         if (!desc.name) {
 531                 ret = -ENOMEM;
 532                 goto out;
 533         }
 534
 535         pdata = coresight_get_platform_data(dev);
 536         if (IS_ERR(pdata)) {
 537                 ret = PTR_ERR(pdata);
 538                 goto out;
 539         }
 540         adev->dev.platform_data = pdata;
 541         desc.pdata = pdata;
 542
 543         drvdata->csdev = coresight_register(&desc);
 544         if (IS_ERR(drvdata->csdev)) {
 545                 ret = PTR_ERR(drvdata->csdev);
 546                 goto out;
 547         }
 548
 549         drvdata->miscdev.name = desc.name;
 550         drvdata->miscdev.minor = MISC_DYNAMIC_MINOR;
 551         drvdata->miscdev.fops = &tmc_fops;
 552         ret = misc_register(&drvdata->miscdev);
 553         if (ret)
 554                 coresight_unregister(drvdata->csdev);
 555         else
 556                 pm_runtime_put(&adev->dev);
 557 out:
 558         return ret;
 559 }
 560
 561 static void tmc_shutdown(struct amba_device *adev)
 562 {
 563         unsigned long flags;
 564         struct tmc_drvdata *drvdata = amba_get_drvdata(adev);
 565
 566         spin_lock_irqsave(&drvdata->spinlock, flags);
 567
 568         if (drvdata->mode == CS_MODE_DISABLED)
 569                 goto out;
 570
 571         if (drvdata->config_type == TMC_CONFIG_TYPE_ETR)
 572                 tmc_etr_disable_hw(drvdata);
 573
 574         /*
 575          * We do not care about coresight unregister here unlike remove
 576          * callback which is required for making coresight modular since
 577          * the system is going down after this.
 578          */
 579 out:
 580         spin_unlock_irqrestore(&drvdata->spinlock, flags);
 581 }
 582
 583 static void tmc_remove(struct amba_device *adev)
 584 {
 585         struct tmc_drvdata *drvdata = dev_get_drvdata(&adev->dev);
 586
 587         /*
 588          * Since misc_open() holds a refcount on the f_ops, which is
 589          * etb fops in this case, device is there until last file
 590          * handler to this device is closed.
 591          */
 592         misc_deregister(&drvdata->miscdev);
 593         coresight_unregister(drvdata->csdev);
 594 }
 595
 596 static const struct amba_id tmc_ids[] = {
 597         CS_AMBA_ID(0x000bb961),
 598         /* Coresight SoC 600 TMC-ETR/ETS */
 599         CS_AMBA_ID_DATA(0x000bb9e8, (unsigned long)CORESIGHT_SOC_600_ETR_CAPS),
 600         /* Coresight SoC 600 TMC-ETB */
 601         CS_AMBA_ID(0x000bb9e9),
 602         /* Coresight SoC 600 TMC-ETF */
 603         CS_AMBA_ID(0x000bb9ea),
 604         { 0, 0},
 605 };
 606
 607 MODULE_DEVICE_TABLE(amba, tmc_ids);
 608
 609 static struct amba_driver tmc_driver = {
 610         .drv = {
 611                 .name   = "coresight-tmc",
 612                 .owner  = THIS_MODULE,
 613                 .suppress_bind_attrs = true,
 614         },
 615         .probe          = tmc_probe,
 616         .shutdown       = tmc_shutdown,
 617         .remove         = tmc_remove,
 618         .id_table       = tmc_ids,
 619 };
 620
 621 module_amba_driver(tmc_driver);
 622
 623 MODULE_AUTHOR("Pratik Patel <[email protected]>");
 624 MODULE_DESCRIPTION("Arm CoreSight Trace Memory Controller driver");
 625 MODULE_LICENSE("GPL v2");