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[BUS_ID_SIZE];
  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[BUS_ID_SIZE];
  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(nr_channels,
  39                 "Maximum number of channels to use (default: all)");
  40
  41 /*
  42  * Initialization patterns. All bytes in the source buffer has bit 7
  43  * set, all bytes in the destination buffer has bit 7 cleared.
  44  *
  45  * Bit 6 is set for all bytes which are to be copied by the DMA
  46  * engine. Bit 5 is set for all bytes which are to be overwritten by
  47  * the DMA engine.
  48  *
  49  * The remaining bits are the inverse of a counter which increments by
  50  * one for each byte address.
  51  */
  52 #define PATTERN_SRC             0x80
  53 #define PATTERN_DST             0x00
  54 #define PATTERN_COPY            0x40
  55 #define PATTERN_OVERWRITE       0x20
  56 #define PATTERN_COUNT_MASK      0x1f
  57
  58 struct dmatest_thread {
  59         struct list_head        node;
  60         struct task_struct      *task;
  61         struct dma_chan         *chan;
  62         u8                      *srcbuf;
  63         u8                      *dstbuf;
  64 };
  65
  66 struct dmatest_chan {
  67         struct list_head        node;
  68         struct dma_chan         *chan;
  69         struct list_head        threads;
  70 };
  71
  72 /*
  73  * These are protected by dma_list_mutex since they're only used by
  74  * the DMA client event callback
  75  */
  76 static LIST_HEAD(dmatest_channels);
  77 static unsigned int nr_channels;
  78
  79 static bool dmatest_match_channel(struct dma_chan *chan)
  80 {
  81         if (test_channel[0] == '\0')
  82                 return true;
  83         return strcmp(chan->dev.bus_id, test_channel) == 0;
  84 }
  85
  86 static bool dmatest_match_device(struct dma_device *device)
  87 {
  88         if (test_device[0] == '\0')
  89                 return true;
  90         return strcmp(device->dev->bus_id, test_device) == 0;
  91 }
  92
  93 static unsigned long dmatest_random(void)
  94 {
  95         unsigned long buf;
  96
  97         get_random_bytes(&buf, sizeof(buf));
  98         return buf;
  99 }
 100
 101 static void dmatest_init_srcbuf(u8 *buf, unsigned int start, unsigned int len)
 102 {
 103         unsigned int i;
 104
 105         for (i = 0; i < start; i++)
 106                 buf[i] = PATTERN_SRC | (~i & PATTERN_COUNT_MASK);
 107         for ( ; i < start + len; i++)
 108                 buf[i] = PATTERN_SRC | PATTERN_COPY
 109                         | (~i & PATTERN_COUNT_MASK);;
 110         for ( ; i < test_buf_size; i++)
 111                 buf[i] = PATTERN_SRC | (~i & PATTERN_COUNT_MASK);
 112 }
 113
 114 static void dmatest_init_dstbuf(u8 *buf, unsigned int start, unsigned int len)
 115 {
 116         unsigned int i;
 117
 118         for (i = 0; i < start; i++)
 119                 buf[i] = PATTERN_DST | (~i & PATTERN_COUNT_MASK);
 120         for ( ; i < start + len; i++)
 121                 buf[i] = PATTERN_DST | PATTERN_OVERWRITE
 122                         | (~i & PATTERN_COUNT_MASK);
 123         for ( ; i < test_buf_size; i++)
 124                 buf[i] = PATTERN_DST | (~i & PATTERN_COUNT_MASK);
 125 }
 126
 127 static void dmatest_mismatch(u8 actual, u8 pattern, unsigned int index,
 128                 unsigned int counter, bool is_srcbuf)
 129 {
 130         u8              diff = actual ^ pattern;
 131         u8              expected = pattern | (~counter & PATTERN_COUNT_MASK);
 132         const char      *thread_name = current->comm;
 133
 134         if (is_srcbuf)
 135                 pr_warning("%s: srcbuf[0x%x] overwritten!"
 136                                 " Expected %02x, got %02x\n",
 137                                 thread_name, index, expected, actual);
 138         else if ((pattern & PATTERN_COPY)
 139                         && (diff & (PATTERN_COPY | PATTERN_OVERWRITE)))
 140                 pr_warning("%s: dstbuf[0x%x] not copied!"
 141                                 " Expected %02x, got %02x\n",
 142                                 thread_name, index, expected, actual);
 143         else if (diff & PATTERN_SRC)
 144                 pr_warning("%s: dstbuf[0x%x] was copied!"
 145                                 " Expected %02x, got %02x\n",
 146                                 thread_name, index, expected, actual);
 147         else
 148                 pr_warning("%s: dstbuf[0x%x] mismatch!"
 149                                 " Expected %02x, got %02x\n",
 150                                 thread_name, index, expected, actual);
 151 }
 152
 153 static unsigned int dmatest_verify(u8 *buf, unsigned int start,
 154                 unsigned int end, unsigned int counter, u8 pattern,
 155                 bool is_srcbuf)
 156 {
 157         unsigned int i;
 158         unsigned int error_count = 0;
 159         u8 actual;
 160
 161         for (i = start; i < end; i++) {
 162                 actual = buf[i];
 163                 if (actual != (pattern | (~counter & PATTERN_COUNT_MASK))) {
 164                         if (error_count < 32)
 165                                 dmatest_mismatch(actual, pattern, i, counter,
 166                                                 is_srcbuf);
 167                         error_count++;
 168                 }
 169                 counter++;
 170         }
 171
 172         if (error_count > 32)
 173                 pr_warning("%s: %u errors suppressed\n",
 174                         current->comm, error_count - 32);
 175
 176         return error_count;
 177 }
 178
 179 /*
 180  * This function repeatedly tests DMA transfers of various lengths and
 181  * offsets until it is told to exit by kthread_stop(). There may be
 182  * multiple threads running this function in parallel for a single
 183  * channel, and there may be multiple channels being tested in
 184  * parallel.
 185  *
 186  * Before each test, the source and destination buffer is initialized
 187  * with a known pattern. This pattern is different depending on
 188  * whether it's in an area which is supposed to be copied or
 189  * overwritten, and different in the source and destination buffers.
 190  * So if the DMA engine doesn't copy exactly what we tell it to copy,
 191  * we'll notice.
 192  */
 193 static int dmatest_func(void *data)
 194 {
 195         struct dmatest_thread   *thread = data;
 196         struct dma_chan         *chan;
 197         const char              *thread_name;
 198         unsigned int            src_off, dst_off, len;
 199         unsigned int            error_count;
 200         unsigned int            failed_tests = 0;
 201         unsigned int            total_tests = 0;
 202         dma_cookie_t            cookie;
 203         enum dma_status         status;
 204         int                     ret;
 205
 206         thread_name = current->comm;
 207
 208         ret = -ENOMEM;
 209         thread->srcbuf = kmalloc(test_buf_size, GFP_KERNEL);
 210         if (!thread->srcbuf)
 211                 goto err_srcbuf;
 212         thread->dstbuf = kmalloc(test_buf_size, GFP_KERNEL);
 213         if (!thread->dstbuf)
 214                 goto err_dstbuf;
 215
 216         smp_rmb();
 217         chan = thread->chan;
 218         dma_chan_get(chan);
 219
 220         while (!kthread_should_stop()) {
 221                 total_tests++;
 222
 223                 len = dmatest_random() % test_buf_size + 1;
 224                 src_off = dmatest_random() % (test_buf_size - len + 1);
 225                 dst_off = dmatest_random() % (test_buf_size - len + 1);
 226
 227                 dmatest_init_srcbuf(thread->srcbuf, src_off, len);
 228                 dmatest_init_dstbuf(thread->dstbuf, dst_off, len);
 229
 230                 cookie = dma_async_memcpy_buf_to_buf(chan,
 231                                 thread->dstbuf + dst_off,
 232                                 thread->srcbuf + src_off,
 233                                 len);
 234                 if (dma_submit_error(cookie)) {
 235                         pr_warning("%s: #%u: submit error %d with src_off=0x%x "
 236                                         "dst_off=0x%x len=0x%x\n",
 237                                         thread_name, total_tests - 1, cookie,
 238                                         src_off, dst_off, len);
 239                         msleep(100);
 240                         failed_tests++;
 241                         continue;
 242                 }
 243                 dma_async_memcpy_issue_pending(chan);
 244
 245                 do {
 246                         msleep(1);
 247                         status = dma_async_memcpy_complete(
 248                                         chan, cookie, NULL, NULL);
 249                 } while (status == DMA_IN_PROGRESS);
 250
 251                 if (status == DMA_ERROR) {
 252                         pr_warning("%s: #%u: error during copy\n",
 253                                         thread_name, total_tests - 1);
 254                         failed_tests++;
 255                         continue;
 256                 }
 257
 258                 error_count = 0;
 259
 260                 pr_debug("%s: verifying source buffer...\n", thread_name);
 261                 error_count += dmatest_verify(thread->srcbuf, 0, src_off,
 262                                 0, PATTERN_SRC, true);
 263                 error_count += dmatest_verify(thread->srcbuf, src_off,
 264                                 src_off + len, src_off,
 265                                 PATTERN_SRC | PATTERN_COPY, true);
 266                 error_count += dmatest_verify(thread->srcbuf, src_off + len,
 267                                 test_buf_size, src_off + len,
 268                                 PATTERN_SRC, true);
 269
 270                 pr_debug("%s: verifying dest buffer...\n",
 271                                 thread->task->comm);
 272                 error_count += dmatest_verify(thread->dstbuf, 0, dst_off,
 273                                 0, PATTERN_DST, false);
 274                 error_count += dmatest_verify(thread->dstbuf, dst_off,
 275                                 dst_off + len, src_off,
 276                                 PATTERN_SRC | PATTERN_COPY, false);
 277                 error_count += dmatest_verify(thread->dstbuf, dst_off + len,
 278                                 test_buf_size, dst_off + len,
 279                                 PATTERN_DST, false);
 280
 281                 if (error_count) {
 282                         pr_warning("%s: #%u: %u errors with "
 283                                 "src_off=0x%x dst_off=0x%x len=0x%x\n",
 284                                 thread_name, total_tests - 1, error_count,
 285                                 src_off, dst_off, len);
 286                         failed_tests++;
 287                 } else {
 288                         pr_debug("%s: #%u: No errors with "
 289                                 "src_off=0x%x dst_off=0x%x len=0x%x\n",
 290                                 thread_name, total_tests - 1,
 291                                 src_off, dst_off, len);
 292                 }
 293         }
 294
 295         ret = 0;
 296         dma_chan_put(chan);
 297         kfree(thread->dstbuf);
 298 err_dstbuf:
 299         kfree(thread->srcbuf);
 300 err_srcbuf:
 301         pr_notice("%s: terminating after %u tests, %u failures (status %d)\n",
 302                         thread_name, total_tests, failed_tests, ret);
 303         return ret;
 304 }
 305
 306 static void dmatest_cleanup_channel(struct dmatest_chan *dtc)
 307 {
 308         struct dmatest_thread   *thread;
 309         struct dmatest_thread   *_thread;
 310         int                     ret;
 311
 312         list_for_each_entry_safe(thread, _thread, &dtc->threads, node) {
 313                 ret = kthread_stop(thread->task);
 314                 pr_debug("dmatest: thread %s exited with status %d\n",
 315                                 thread->task->comm, ret);
 316                 list_del(&thread->node);
 317                 kfree(thread);
 318         }
 319         kfree(dtc);
 320 }
 321
 322 static enum dma_state_client dmatest_add_channel(struct dma_chan *chan)
 323 {
 324         struct dmatest_chan     *dtc;
 325         struct dmatest_thread   *thread;
 326         unsigned int            i;
 327
 328         dtc = kmalloc(sizeof(struct dmatest_chan), GFP_ATOMIC);
 329         if (!dtc) {
 330                 pr_warning("dmatest: No memory for %s\n", chan->dev.bus_id);
 331                 return DMA_NAK;
 332         }
 333
 334         dtc->chan = chan;
 335         INIT_LIST_HEAD(&dtc->threads);
 336
 337         for (i = 0; i < threads_per_chan; i++) {
 338                 thread = kzalloc(sizeof(struct dmatest_thread), GFP_KERNEL);
 339                 if (!thread) {
 340                         pr_warning("dmatest: No memory for %s-test%u\n",
 341                                         chan->dev.bus_id, i);
 342                         break;
 343                 }
 344                 thread->chan = dtc->chan;
 345                 smp_wmb();
 346                 thread->task = kthread_run(dmatest_func, thread, "%s-test%u",
 347                                 chan->dev.bus_id, i);
 348                 if (IS_ERR(thread->task)) {
 349                         pr_warning("dmatest: Failed to run thread %s-test%u\n",
 350                                         chan->dev.bus_id, i);
 351                         kfree(thread);
 352                         break;
 353                 }
 354
 355                 /* srcbuf and dstbuf are allocated by the thread itself */
 356
 357                 list_add_tail(&thread->node, &dtc->threads);
 358         }
 359
 360         pr_info("dmatest: Started %u threads using %s\n", i, chan->dev.bus_id);
 361
 362         list_add_tail(&dtc->node, &dmatest_channels);
 363         nr_channels++;
 364
 365         return DMA_ACK;
 366 }
 367
 368 static enum dma_state_client dmatest_remove_channel(struct dma_chan *chan)
 369 {
 370         struct dmatest_chan     *dtc, *_dtc;
 371
 372         list_for_each_entry_safe(dtc, _dtc, &dmatest_channels, node) {
 373                 if (dtc->chan == chan) {
 374                         list_del(&dtc->node);
 375                         dmatest_cleanup_channel(dtc);
 376                         pr_debug("dmatest: lost channel %s\n",
 377                                         chan->dev.bus_id);
 378                         return DMA_ACK;
 379                 }
 380         }
 381
 382         return DMA_DUP;
 383 }
 384
 385 /*
 386  * Start testing threads as new channels are assigned to us, and kill
 387  * them when the channels go away.
 388  *
 389  * When we unregister the client, all channels are removed so this
 390  * will also take care of cleaning things up when the module is
 391  * unloaded.
 392  */
 393 static enum dma_state_client
 394 dmatest_event(struct dma_client *client, struct dma_chan *chan,
 395                 enum dma_state state)
 396 {
 397         enum dma_state_client   ack = DMA_NAK;
 398
 399         switch (state) {
 400         case DMA_RESOURCE_AVAILABLE:
 401                 if (!dmatest_match_channel(chan)
 402                                 || !dmatest_match_device(chan->device))
 403                         ack = DMA_DUP;
 404                 else if (max_channels && nr_channels >= max_channels)
 405                         ack = DMA_NAK;
 406                 else
 407                         ack = dmatest_add_channel(chan);
 408                 break;
 409
 410         case DMA_RESOURCE_REMOVED:
 411                 ack = dmatest_remove_channel(chan);
 412                 break;
 413
 414         default:
 415                 pr_info("dmatest: Unhandled event %u (%s)\n",
 416                                 state, chan->dev.bus_id);
 417                 break;
 418         }
 419
 420         return ack;
 421 }
 422
 423 static struct dma_client dmatest_client = {
 424         .event_callback = dmatest_event,
 425 };
 426
 427 static int __init dmatest_init(void)
 428 {
 429         dma_cap_set(DMA_MEMCPY, dmatest_client.cap_mask);
 430         dma_async_client_register(&dmatest_client);
 431         dma_async_client_chan_request(&dmatest_client);
 432
 433         return 0;
 434 }
 435 module_init(dmatest_init);
 436
 437 static void __exit dmatest_exit(void)
 438 {
 439         dma_async_client_unregister(&dmatest_client);
 440 }
 441 module_exit(dmatest_exit);
 442
 443 MODULE_AUTHOR("Haavard Skinnemoen <hskinnemoen@atmel.com>");
 444 MODULE_LICENSE("GPL v2");