drivers/dma/dmatest.c

   1 /*
   2  * DMA Engine test module
   3  *
   4  * Copyright (C) 2007 Atmel Corporation
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  */
  10 #include <linux/delay.h>
  11 #include <linux/dmaengine.h>
  12 #include <linux/init.h>
  13 #include <linux/kthread.h>
  14 #include <linux/module.h>
  15 #include <linux/moduleparam.h>
  16 #include <linux/random.h>
  17 #include <linux/wait.h>
  18
  19 static unsigned int test_buf_size = 16384;
  20 module_param(test_buf_size, uint, S_IRUGO);
  21 MODULE_PARM_DESC(test_buf_size, "Size of the memcpy test buffer");
  22
  23 static char test_channel[20];
  24 module_param_string(channel, test_channel, sizeof(test_channel), S_IRUGO);
  25 MODULE_PARM_DESC(channel, "Bus ID of the channel to test (default: any)");
  26
  27 static char test_device[20];
  28 module_param_string(device, test_device, sizeof(test_device), S_IRUGO);
  29 MODULE_PARM_DESC(device, "Bus ID of the DMA Engine to test (default: any)");
  30
  31 static unsigned int threads_per_chan = 1;
  32 module_param(threads_per_chan, uint, S_IRUGO);
  33 MODULE_PARM_DESC(threads_per_chan,
  34                 "Number of threads to start per channel (default: 1)");
  35
  36 static unsigned int max_channels;
  37 module_param(max_channels, uint, S_IRUGO);
  38 MODULE_PARM_DESC(max_channels,
  39                 "Maximum number of channels to use (default: all)");
  40
  41 static unsigned int iterations;
  42 module_param(iterations, uint, S_IRUGO);
  43 MODULE_PARM_DESC(iterations,
  44                 "Iterations before stopping test (default: infinite)");
  45
  46 static unsigned int xor_sources = 3;
  47 module_param(xor_sources, uint, S_IRUGO);
  48 MODULE_PARM_DESC(xor_sources,
  49                 "Number of xor source buffers (default: 3)");
  50
  51 static unsigned int pq_sources = 3;
  52 module_param(pq_sources, uint, S_IRUGO);
  53 MODULE_PARM_DESC(pq_sources,
  54                 "Number of p+q source buffers (default: 3)");
  55
  56 /*
  57  * Initialization patterns. All bytes in the source buffer has bit 7
  58  * set, all bytes in the destination buffer has bit 7 cleared.
  59  *
  60  * Bit 6 is set for all bytes which are to be copied by the DMA
  61  * engine. Bit 5 is set for all bytes which are to be overwritten by
  62  * the DMA engine.
  63  *
  64  * The remaining bits are the inverse of a counter which increments by
  65  * one for each byte address.
  66  */
  67 #define PATTERN_SRC             0x80
  68 #define PATTERN_DST             0x00
  69 #define PATTERN_COPY            0x40
  70 #define PATTERN_OVERWRITE       0x20
  71 #define PATTERN_COUNT_MASK      0x1f
  72
  73 struct dmatest_thread {
  74         struct list_head        node;
  75         struct task_struct      *task;
  76         struct dma_chan         *chan;
  77         u8                      **srcs;
  78         u8                      **dsts;
  79         enum dma_transaction_type type;
  80 };
  81
  82 struct dmatest_chan {
  83         struct list_head        node;
  84         struct dma_chan         *chan;
  85         struct list_head        threads;
  86 };
  87
  88 /*
  89  * These are protected by dma_list_mutex since they're only used by
  90  * the DMA filter function callback
  91  */
  92 static LIST_HEAD(dmatest_channels);
  93 static unsigned int nr_channels;
  94
  95 static bool dmatest_match_channel(struct dma_chan *chan)
  96 {
  97         if (test_channel[0] == '\0')
  98                 return true;
  99         return strcmp(dma_chan_name(chan), test_channel) == 0;
 100 }
 101
 102 static bool dmatest_match_device(struct dma_device *device)
 103 {
 104         if (test_device[0] == '\0')
 105                 return true;
 106         return strcmp(dev_name(device->dev), test_device) == 0;
 107 }
 108
 109 static unsigned long dmatest_random(void)
 110 {
 111         unsigned long buf;
 112
 113         get_random_bytes(&buf, sizeof(buf));
 114         return buf;
 115 }
 116
 117 static void dmatest_init_srcs(u8 **bufs, unsigned int start, unsigned int len)
 118 {
 119         unsigned int i;
 120         u8 *buf;
 121
 122         for (; (buf = *bufs); bufs++) {
 123                 for (i = 0; i < start; i++)
 124                         buf[i] = PATTERN_SRC | (~i & PATTERN_COUNT_MASK);
 125                 for ( ; i < start + len; i++)
 126                         buf[i] = PATTERN_SRC | PATTERN_COPY
 127                                 | (~i & PATTERN_COUNT_MASK);
 128                 for ( ; i < test_buf_size; i++)
 129                         buf[i] = PATTERN_SRC | (~i & PATTERN_COUNT_MASK);
 130                 buf++;
 131         }
 132 }
 133
 134 static void dmatest_init_dsts(u8 **bufs, unsigned int start, unsigned int len)
 135 {
 136         unsigned int i;
 137         u8 *buf;
 138
 139         for (; (buf = *bufs); bufs++) {
 140                 for (i = 0; i < start; i++)
 141                         buf[i] = PATTERN_DST | (~i & PATTERN_COUNT_MASK);
 142                 for ( ; i < start + len; i++)
 143                         buf[i] = PATTERN_DST | PATTERN_OVERWRITE
 144                                 | (~i & PATTERN_COUNT_MASK);
 145                 for ( ; i < test_buf_size; i++)
 146                         buf[i] = PATTERN_DST | (~i & PATTERN_COUNT_MASK);
 147         }
 148 }
 149
 150 static void dmatest_mismatch(u8 actual, u8 pattern, unsigned int index,
 151                 unsigned int counter, bool is_srcbuf)
 152 {
 153         u8              diff = actual ^ pattern;
 154         u8              expected = pattern | (~counter & PATTERN_COUNT_MASK);
 155         const char      *thread_name = current->comm;
 156
 157         if (is_srcbuf)
 158                 pr_warning("%s: srcbuf[0x%x] overwritten!"
 159                                 " Expected %02x, got %02x\n",
 160                                 thread_name, index, expected, actual);
 161         else if ((pattern & PATTERN_COPY)
 162                         && (diff & (PATTERN_COPY | PATTERN_OVERWRITE)))
 163                 pr_warning("%s: dstbuf[0x%x] not copied!"
 164                                 " Expected %02x, got %02x\n",
 165                                 thread_name, index, expected, actual);
 166         else if (diff & PATTERN_SRC)
 167                 pr_warning("%s: dstbuf[0x%x] was copied!"
 168                                 " Expected %02x, got %02x\n",
 169                                 thread_name, index, expected, actual);
 170         else
 171                 pr_warning("%s: dstbuf[0x%x] mismatch!"
 172                                 " Expected %02x, got %02x\n",
 173                                 thread_name, index, expected, actual);
 174 }
 175
 176 static unsigned int dmatest_verify(u8 **bufs, unsigned int start,
 177                 unsigned int end, unsigned int counter, u8 pattern,
 178                 bool is_srcbuf)
 179 {
 180         unsigned int i;
 181         unsigned int error_count = 0;
 182         u8 actual;
 183         u8 expected;
 184         u8 *buf;
 185         unsigned int counter_orig = counter;
 186
 187         for (; (buf = *bufs); bufs++) {
 188                 counter = counter_orig;
 189                 for (i = start; i < end; i++) {
 190                         actual = buf[i];
 191                         expected = pattern | (~counter & PATTERN_COUNT_MASK);
 192                         if (actual != expected) {
 193                                 if (error_count < 32)
 194                                         dmatest_mismatch(actual, pattern, i,
 195                                                          counter, is_srcbuf);
 196                                 error_count++;
 197                         }
 198                         counter++;
 199                 }
 200         }
 201
 202         if (error_count > 32)
 203                 pr_warning("%s: %u errors suppressed\n",
 204                         current->comm, error_count - 32);
 205
 206         return error_count;
 207 }
 208
 209 static void dmatest_callback(void *completion)
 210 {
 211         complete(completion);
 212 }
 213
 214 /*
 215  * This function repeatedly tests DMA transfers of various lengths and
 216  * offsets for a given operation type until it is told to exit by
 217  * kthread_stop(). There may be multiple threads running this function
 218  * in parallel for a single channel, and there may be multiple channels
 219  * being tested in parallel.
 220  *
 221  * Before each test, the source and destination buffer is initialized
 222  * with a known pattern. This pattern is different depending on
 223  * whether it's in an area which is supposed to be copied or
 224  * overwritten, and different in the source and destination buffers.
 225  * So if the DMA engine doesn't copy exactly what we tell it to copy,
 226  * we'll notice.
 227  */
 228 static int dmatest_func(void *data)
 229 {
 230         struct dmatest_thread   *thread = data;
 231         struct dma_chan         *chan;
 232         const char              *thread_name;
 233         unsigned int            src_off, dst_off, len;
 234         unsigned int            error_count;
 235         unsigned int            failed_tests = 0;
 236         unsigned int            total_tests = 0;
 237         dma_cookie_t            cookie;
 238         enum dma_status         status;
 239         enum dma_ctrl_flags     flags;
 240         u8                      pq_coefs[pq_sources];
 241         int                     ret;
 242         int                     src_cnt;
 243         int                     dst_cnt;
 244         int                     i;
 245
 246         thread_name = current->comm;
 247
 248         ret = -ENOMEM;
 249
 250         smp_rmb();
 251         chan = thread->chan;
 252         if (thread->type == DMA_MEMCPY)
 253                 src_cnt = dst_cnt = 1;
 254         else if (thread->type == DMA_XOR) {
 255                 src_cnt = xor_sources | 1; /* force odd to ensure dst = src */
 256                 dst_cnt = 1;
 257         } else if (thread->type == DMA_PQ) {
 258                 src_cnt = pq_sources | 1; /* force odd to ensure dst = src */
 259                 dst_cnt = 2;
 260                 for (i = 0; i < pq_sources; i++)
 261                         pq_coefs[i] = 1;
 262         } else
 263                 goto err_srcs;
 264
 265         thread->srcs = kcalloc(src_cnt+1, sizeof(u8 *), GFP_KERNEL);
 266         if (!thread->srcs)
 267                 goto err_srcs;
 268         for (i = 0; i < src_cnt; i++) {
 269                 thread->srcs[i] = kmalloc(test_buf_size, GFP_KERNEL);
 270                 if (!thread->srcs[i])
 271                         goto err_srcbuf;
 272         }
 273         thread->srcs[i] = NULL;
 274
 275         thread->dsts = kcalloc(dst_cnt+1, sizeof(u8 *), GFP_KERNEL);
 276         if (!thread->dsts)
 277                 goto err_dsts;
 278         for (i = 0; i < dst_cnt; i++) {
 279                 thread->dsts[i] = kmalloc(test_buf_size, GFP_KERNEL);
 280                 if (!thread->dsts[i])
 281                         goto err_dstbuf;
 282         }
 283         thread->dsts[i] = NULL;
 284
 285         set_user_nice(current, 10);
 286
 287         flags = DMA_CTRL_ACK | DMA_COMPL_SKIP_DEST_UNMAP | DMA_PREP_INTERRUPT;
 288
 289         while (!kthread_should_stop()
 290                && !(iterations && total_tests >= iterations)) {
 291                 struct dma_device *dev = chan->device;
 292                 struct dma_async_tx_descriptor *tx = NULL;
 293                 dma_addr_t dma_srcs[src_cnt];
 294                 dma_addr_t dma_dsts[dst_cnt];
 295                 struct completion cmp;
 296                 unsigned long tmo = msecs_to_jiffies(3000);
 297                 u8 align = 0;
 298
 299                 total_tests++;
 300
 301                 len = dmatest_random() % test_buf_size + 1;
 302                 src_off = dmatest_random() % (test_buf_size - len + 1);
 303                 dst_off = dmatest_random() % (test_buf_size - len + 1);
 304
 305                 /* honor alignment restrictions */
 306                 if (thread->type == DMA_MEMCPY)
 307                         align = dev->copy_align;
 308                 else if (thread->type == DMA_XOR)
 309                         align = dev->xor_align;
 310                 else if (thread->type == DMA_PQ)
 311                         align = dev->pq_align;
 312
 313                 len = (len >> align) << align;
 314                 src_off = (src_off >> align) << align;
 315                 dst_off = (dst_off >> align) << align;
 316
 317                 dmatest_init_srcs(thread->srcs, src_off, len);
 318                 dmatest_init_dsts(thread->dsts, dst_off, len);
 319
 320                 for (i = 0; i < src_cnt; i++) {
 321                         u8 *buf = thread->srcs[i] + src_off;
 322
 323                         dma_srcs[i] = dma_map_single(dev->dev, buf, len,
 324                                                      DMA_TO_DEVICE);
 325                 }
 326                 /* map with DMA_BIDIRECTIONAL to force writeback/invalidate */
 327                 for (i = 0; i < dst_cnt; i++) {
 328                         dma_dsts[i] = dma_map_single(dev->dev, thread->dsts[i],
 329                                                      test_buf_size,
 330                                                      DMA_BIDIRECTIONAL);
 331                 }
 332
 333
 334                 if (thread->type == DMA_MEMCPY)
 335                         tx = dev->device_prep_dma_memcpy(chan,
 336                                                          dma_dsts[0] + dst_off,
 337                                                          dma_srcs[0], len,
 338                                                          flags);
 339                 else if (thread->type == DMA_XOR)
 340                         tx = dev->device_prep_dma_xor(chan,
 341                                                       dma_dsts[0] + dst_off,
 342                                                       dma_srcs, xor_sources,
 343                                                       len, flags);
 344                 else if (thread->type == DMA_PQ) {
 345                         dma_addr_t dma_pq[dst_cnt];
 346
 347                         for (i = 0; i < dst_cnt; i++)
 348                                 dma_pq[i] = dma_dsts[i] + dst_off;
 349                         tx = dev->device_prep_dma_pq(chan, dma_pq, dma_srcs,
 350                                                      pq_sources, pq_coefs,
 351                                                      len, flags);
 352                 }
 353
 354                 if (!tx) {
 355                         for (i = 0; i < src_cnt; i++)
 356                                 dma_unmap_single(dev->dev, dma_srcs[i], len,
 357                                                  DMA_TO_DEVICE);
 358                         for (i = 0; i < dst_cnt; i++)
 359                                 dma_unmap_single(dev->dev, dma_dsts[i],
 360                                                  test_buf_size,
 361                                                  DMA_BIDIRECTIONAL);
 362                         pr_warning("%s: #%u: prep error with src_off=0x%x "
 363                                         "dst_off=0x%x len=0x%x\n",
 364                                         thread_name, total_tests - 1,
 365                                         src_off, dst_off, len);
 366                         msleep(100);
 367                         failed_tests++;
 368                         continue;
 369                 }
 370
 371                 init_completion(&cmp);
 372                 tx->callback = dmatest_callback;
 373                 tx->callback_param = &cmp;
 374                 cookie = tx->tx_submit(tx);
 375
 376                 if (dma_submit_error(cookie)) {
 377                         pr_warning("%s: #%u: submit error %d with src_off=0x%x "
 378                                         "dst_off=0x%x len=0x%x\n",
 379                                         thread_name, total_tests - 1, cookie,
 380                                         src_off, dst_off, len);
 381                         msleep(100);
 382                         failed_tests++;
 383                         continue;
 384                 }
 385                 dma_async_issue_pending(chan);
 386
 387                 tmo = wait_for_completion_timeout(&cmp, tmo);
 388                 status = dma_async_is_tx_complete(chan, cookie, NULL, NULL);
 389
 390                 if (tmo == 0) {
 391                         pr_warning("%s: #%u: test timed out\n",
 392                                    thread_name, total_tests - 1);
 393                         failed_tests++;
 394                         continue;
 395                 } else if (status != DMA_SUCCESS) {
 396                         pr_warning("%s: #%u: got completion callback,"
 397                                    " but status is \'%s\'\n",
 398                                    thread_name, total_tests - 1,
 399                                    status == DMA_ERROR ? "error" : "in progress");
 400                         failed_tests++;
 401                         continue;
 402                 }
 403
 404                 /* Unmap by myself (see DMA_COMPL_SKIP_DEST_UNMAP above) */
 405                 for (i = 0; i < dst_cnt; i++)
 406                         dma_unmap_single(dev->dev, dma_dsts[i], test_buf_size,
 407                                          DMA_BIDIRECTIONAL);
 408
 409                 error_count = 0;
 410
 411                 pr_debug("%s: verifying source buffer...\n", thread_name);
 412                 error_count += dmatest_verify(thread->srcs, 0, src_off,
 413                                 0, PATTERN_SRC, true);
 414                 error_count += dmatest_verify(thread->srcs, src_off,
 415                                 src_off + len, src_off,
 416                                 PATTERN_SRC | PATTERN_COPY, true);
 417                 error_count += dmatest_verify(thread->srcs, src_off + len,
 418                                 test_buf_size, src_off + len,
 419                                 PATTERN_SRC, true);
 420
 421                 pr_debug("%s: verifying dest buffer...\n",
 422                                 thread->task->comm);
 423                 error_count += dmatest_verify(thread->dsts, 0, dst_off,
 424                                 0, PATTERN_DST, false);
 425                 error_count += dmatest_verify(thread->dsts, dst_off,
 426                                 dst_off + len, src_off,
 427                                 PATTERN_SRC | PATTERN_COPY, false);
 428                 error_count += dmatest_verify(thread->dsts, dst_off + len,
 429                                 test_buf_size, dst_off + len,
 430                                 PATTERN_DST, false);
 431
 432                 if (error_count) {
 433                         pr_warning("%s: #%u: %u errors with "
 434                                 "src_off=0x%x dst_off=0x%x len=0x%x\n",
 435                                 thread_name, total_tests - 1, error_count,
 436                                 src_off, dst_off, len);
 437                         failed_tests++;
 438                 } else {
 439                         pr_debug("%s: #%u: No errors with "
 440                                 "src_off=0x%x dst_off=0x%x len=0x%x\n",
 441                                 thread_name, total_tests - 1,
 442                                 src_off, dst_off, len);
 443                 }
 444         }
 445
 446         ret = 0;
 447         for (i = 0; thread->dsts[i]; i++)
 448                 kfree(thread->dsts[i]);
 449 err_dstbuf:
 450         kfree(thread->dsts);
 451 err_dsts:
 452         for (i = 0; thread->srcs[i]; i++)
 453                 kfree(thread->srcs[i]);
 454 err_srcbuf:
 455         kfree(thread->srcs);
 456 err_srcs:
 457         pr_notice("%s: terminating after %u tests, %u failures (status %d)\n",
 458                         thread_name, total_tests, failed_tests, ret);
 459
 460         if (iterations > 0)
 461                 while (!kthread_should_stop()) {
 462                         DECLARE_WAIT_QUEUE_HEAD(wait_dmatest_exit);
 463                         interruptible_sleep_on(&wait_dmatest_exit);
 464                 }
 465
 466         return ret;
 467 }
 468
 469 static void dmatest_cleanup_channel(struct dmatest_chan *dtc)
 470 {
 471         struct dmatest_thread   *thread;
 472         struct dmatest_thread   *_thread;
 473         int                     ret;
 474
 475         list_for_each_entry_safe(thread, _thread, &dtc->threads, node) {
 476                 ret = kthread_stop(thread->task);
 477                 pr_debug("dmatest: thread %s exited with status %d\n",
 478                                 thread->task->comm, ret);
 479                 list_del(&thread->node);
 480                 kfree(thread);
 481         }
 482         kfree(dtc);
 483 }
 484
 485 static int dmatest_add_threads(struct dmatest_chan *dtc, enum dma_transaction_type type)
 486 {
 487         struct dmatest_thread *thread;
 488         struct dma_chan *chan = dtc->chan;
 489         char *op;
 490         unsigned int i;
 491
 492         if (type == DMA_MEMCPY)
 493                 op = "copy";
 494         else if (type == DMA_XOR)
 495                 op = "xor";
 496         else if (type == DMA_PQ)
 497                 op = "pq";
 498         else
 499                 return -EINVAL;
 500
 501         for (i = 0; i < threads_per_chan; i++) {
 502                 thread = kzalloc(sizeof(struct dmatest_thread), GFP_KERNEL);
 503                 if (!thread) {
 504                         pr_warning("dmatest: No memory for %s-%s%u\n",
 505                                    dma_chan_name(chan), op, i);
 506
 507                         break;
 508                 }
 509                 thread->chan = dtc->chan;
 510                 thread->type = type;
 511                 smp_wmb();
 512                 thread->task = kthread_run(dmatest_func, thread, "%s-%s%u",
 513                                 dma_chan_name(chan), op, i);
 514                 if (IS_ERR(thread->task)) {
 515                         pr_warning("dmatest: Failed to run thread %s-%s%u\n",
 516                                         dma_chan_name(chan), op, i);
 517                         kfree(thread);
 518                         break;
 519                 }
 520
 521                 /* srcbuf and dstbuf are allocated by the thread itself */
 522
 523                 list_add_tail(&thread->node, &dtc->threads);
 524         }
 525
 526         return i;
 527 }
 528
 529 static int dmatest_add_channel(struct dma_chan *chan)
 530 {
 531         struct dmatest_chan     *dtc;
 532         struct dma_device       *dma_dev = chan->device;
 533         unsigned int            thread_count = 0;
 534         unsigned int            cnt;
 535
 536         dtc = kmalloc(sizeof(struct dmatest_chan), GFP_KERNEL);
 537         if (!dtc) {
 538                 pr_warning("dmatest: No memory for %s\n", dma_chan_name(chan));
 539                 return -ENOMEM;
 540         }
 541
 542         dtc->chan = chan;
 543         INIT_LIST_HEAD(&dtc->threads);
 544
 545         if (dma_has_cap(DMA_MEMCPY, dma_dev->cap_mask)) {
 546                 cnt = dmatest_add_threads(dtc, DMA_MEMCPY);
 547                 thread_count += cnt > 0 ? cnt : 0;
 548         }
 549         if (dma_has_cap(DMA_XOR, dma_dev->cap_mask)) {
 550                 cnt = dmatest_add_threads(dtc, DMA_XOR);
 551                 thread_count += cnt > 0 ? cnt : 0;
 552         }
 553         if (dma_has_cap(DMA_PQ, dma_dev->cap_mask)) {
 554                 cnt = dmatest_add_threads(dtc, DMA_PQ);
 555                 thread_count += cnt > 0 ?: 0;
 556         }
 557
 558         pr_info("dmatest: Started %u threads using %s\n",
 559                 thread_count, dma_chan_name(chan));
 560
 561         list_add_tail(&dtc->node, &dmatest_channels);
 562         nr_channels++;
 563
 564         return 0;
 565 }
 566
 567 static bool filter(struct dma_chan *chan, void *param)
 568 {
 569         if (!dmatest_match_channel(chan) || !dmatest_match_device(chan->device))
 570                 return false;
 571         else
 572                 return true;
 573 }
 574
 575 static int __init dmatest_init(void)
 576 {
 577         dma_cap_mask_t mask;
 578         struct dma_chan *chan;
 579         int err = 0;
 580
 581         dma_cap_zero(mask);
 582         dma_cap_set(DMA_MEMCPY, mask);
 583         for (;;) {
 584                 chan = dma_request_channel(mask, filter, NULL);
 585                 if (chan) {
 586                         err = dmatest_add_channel(chan);
 587                         if (err) {
 588                                 dma_release_channel(chan);
 589                                 break; /* add_channel failed, punt */
 590                         }
 591                 } else
 592                         break; /* no more channels available */
 593                 if (max_channels && nr_channels >= max_channels)
 594                         break; /* we have all we need */
 595         }
 596
 597         return err;
 598 }
 599 /* when compiled-in wait for drivers to load first */
 600 late_initcall(dmatest_init);
 601
 602 static void __exit dmatest_exit(void)
 603 {
 604         struct dmatest_chan *dtc, *_dtc;
 605         struct dma_chan *chan;
 606
 607         list_for_each_entry_safe(dtc, _dtc, &dmatest_channels, node) {
 608                 list_del(&dtc->node);
 609                 chan = dtc->chan;
 610                 dmatest_cleanup_channel(dtc);
 611                 pr_debug("dmatest: dropped channel %s\n",
 612                          dma_chan_name(chan));
 613                 dma_release_channel(chan);
 614         }
 615 }
 616 module_exit(dmatest_exit);
 617
 618 MODULE_AUTHOR("Haavard Skinnemoen <hskinnemoen@atmel.com>");
 619 MODULE_LICENSE("GPL v2");