drivers/dma/sh/shdma-base.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Dmaengine driver base library for DMA controllers, found on SH-based SoCs
   4  *
   5  * extracted from shdma.c
   6  *
   7  * Copyright (C) 2011-2012 Guennadi Liakhovetski <g.liakhovetski@gmx.de>
   8  * Copyright (C) 2009 Nobuhiro Iwamatsu <iwamatsu.nobuhiro@renesas.com>
   9  * Copyright (C) 2009 Renesas Solutions, Inc. All rights reserved.
  10  * Copyright (C) 2007 Freescale Semiconductor, Inc. All rights reserved.
  11  */
  12
  13 #include <linux/delay.h>
  14 #include <linux/shdma-base.h>
  15 #include <linux/dmaengine.h>
  16 #include <linux/init.h>
  17 #include <linux/interrupt.h>
  18 #include <linux/module.h>
  19 #include <linux/pm_runtime.h>
  20 #include <linux/slab.h>
  21 #include <linux/spinlock.h>
  22
  23 #include "../dmaengine.h"
  24
  25 /* DMA descriptor control */
  26 enum shdma_desc_status {
  27         DESC_IDLE,
  28         DESC_PREPARED,
  29         DESC_SUBMITTED,
  30         DESC_COMPLETED, /* completed, have to call callback */
  31         DESC_WAITING,   /* callback called, waiting for ack / re-submit */
  32 };
  33
  34 #define NR_DESCS_PER_CHANNEL 32
  35
  36 #define to_shdma_chan(c) container_of(c, struct shdma_chan, dma_chan)
  37 #define to_shdma_dev(d) container_of(d, struct shdma_dev, dma_dev)
  38
  39 /*
  40  * For slave DMA we assume, that there is a finite number of DMA slaves in the
  41  * system, and that each such slave can only use a finite number of channels.
  42  * We use slave channel IDs to make sure, that no such slave channel ID is
  43  * allocated more than once.
  44  */
  45 static unsigned int slave_num = 256;
  46 module_param(slave_num, uint, 0444);
  47
  48 /* A bitmask with slave_num bits */
  49 static unsigned long *shdma_slave_used;
  50
  51 /* Called under spin_lock_irq(&schan->chan_lock") */
  52 static void shdma_chan_xfer_ld_queue(struct shdma_chan *schan)
  53 {
  54         struct shdma_dev *sdev = to_shdma_dev(schan->dma_chan.device);
  55         const struct shdma_ops *ops = sdev->ops;
  56         struct shdma_desc *sdesc;
  57
  58         /* DMA work check */
  59         if (ops->channel_busy(schan))
  60                 return;
  61
  62         /* Find the first not transferred descriptor */
  63         list_for_each_entry(sdesc, &schan->ld_queue, node)
  64                 if (sdesc->mark == DESC_SUBMITTED) {
  65                         ops->start_xfer(schan, sdesc);
  66                         break;
  67                 }
  68 }
  69
  70 static dma_cookie_t shdma_tx_submit(struct dma_async_tx_descriptor *tx)
  71 {
  72         struct shdma_desc *chunk, *c, *desc =
  73                 container_of(tx, struct shdma_desc, async_tx);
  74         struct shdma_chan *schan = to_shdma_chan(tx->chan);
  75         dma_async_tx_callback callback = tx->callback;
  76         dma_cookie_t cookie;
  77         bool power_up;
  78
  79         spin_lock_irq(&schan->chan_lock);
  80
  81         power_up = list_empty(&schan->ld_queue);
  82
  83         cookie = dma_cookie_assign(tx);
  84
  85         /* Mark all chunks of this descriptor as submitted, move to the queue */
  86         list_for_each_entry_safe(chunk, c, desc->node.prev, node) {
  87                 /*
  88                  * All chunks are on the global ld_free, so, we have to find
  89                  * the end of the chain ourselves
  90                  */
  91                 if (chunk != desc && (chunk->mark == DESC_IDLE ||
  92                                       chunk->async_tx.cookie > 0 ||
  93                                       chunk->async_tx.cookie == -EBUSY ||
  94                                       &chunk->node == &schan->ld_free))
  95                         break;
  96                 chunk->mark = DESC_SUBMITTED;
  97                 if (chunk->chunks == 1) {
  98                         chunk->async_tx.callback = callback;
  99                         chunk->async_tx.callback_param = tx->callback_param;
 100                 } else {
 101                         /* Callback goes to the last chunk */
 102                         chunk->async_tx.callback = NULL;
 103                 }
 104                 chunk->cookie = cookie;
 105                 list_move_tail(&chunk->node, &schan->ld_queue);
 106
 107                 dev_dbg(schan->dev, "submit #%d@%p on %d\n",
 108                         tx->cookie, &chunk->async_tx, schan->id);
 109         }
 110
 111         if (power_up) {
 112                 int ret;
 113                 schan->pm_state = SHDMA_PM_BUSY;
 114
 115                 ret = pm_runtime_get(schan->dev);
 116
 117                 spin_unlock_irq(&schan->chan_lock);
 118                 if (ret < 0)
 119                         dev_err(schan->dev, "%s(): GET = %d\n", __func__, ret);
 120
 121                 pm_runtime_barrier(schan->dev);
 122
 123                 spin_lock_irq(&schan->chan_lock);
 124
 125                 /* Have we been reset, while waiting? */
 126                 if (schan->pm_state != SHDMA_PM_ESTABLISHED) {
 127                         struct shdma_dev *sdev =
 128                                 to_shdma_dev(schan->dma_chan.device);
 129                         const struct shdma_ops *ops = sdev->ops;
 130                         dev_dbg(schan->dev, "Bring up channel %d\n",
 131                                 schan->id);
 132                         /*
 133                          * TODO: .xfer_setup() might fail on some platforms.
 134                          * Make it int then, on error remove chunks from the
 135                          * queue again
 136                          */
 137                         ops->setup_xfer(schan, schan->slave_id);
 138
 139                         if (schan->pm_state == SHDMA_PM_PENDING)
 140                                 shdma_chan_xfer_ld_queue(schan);
 141                         schan->pm_state = SHDMA_PM_ESTABLISHED;
 142                 }
 143         } else {
 144                 /*
 145                  * Tell .device_issue_pending() not to run the queue, interrupts
 146                  * will do it anyway
 147                  */
 148                 schan->pm_state = SHDMA_PM_PENDING;
 149         }
 150
 151         spin_unlock_irq(&schan->chan_lock);
 152
 153         return cookie;
 154 }
 155
 156 /* Called with desc_lock held */
 157 static struct shdma_desc *shdma_get_desc(struct shdma_chan *schan)
 158 {
 159         struct shdma_desc *sdesc;
 160
 161         list_for_each_entry(sdesc, &schan->ld_free, node)
 162                 if (sdesc->mark != DESC_PREPARED) {
 163                         BUG_ON(sdesc->mark != DESC_IDLE);
 164                         list_del(&sdesc->node);
 165                         return sdesc;
 166                 }
 167
 168         return NULL;
 169 }
 170
 171 static int shdma_setup_slave(struct shdma_chan *schan, dma_addr_t slave_addr)
 172 {
 173         struct shdma_dev *sdev = to_shdma_dev(schan->dma_chan.device);
 174         const struct shdma_ops *ops = sdev->ops;
 175         int ret, match;
 176
 177         if (schan->dev->of_node) {
 178                 match = schan->hw_req;
 179                 ret = ops->set_slave(schan, match, slave_addr, true);
 180                 if (ret < 0)
 181                         return ret;
 182         } else {
 183                 match = schan->real_slave_id;
 184         }
 185
 186         if (schan->real_slave_id < 0 || schan->real_slave_id >= slave_num)
 187                 return -EINVAL;
 188
 189         if (test_and_set_bit(schan->real_slave_id, shdma_slave_used))
 190                 return -EBUSY;
 191
 192         ret = ops->set_slave(schan, match, slave_addr, false);
 193         if (ret < 0) {
 194                 clear_bit(schan->real_slave_id, shdma_slave_used);
 195                 return ret;
 196         }
 197
 198         schan->slave_id = schan->real_slave_id;
 199
 200         return 0;
 201 }
 202
 203 static int shdma_alloc_chan_resources(struct dma_chan *chan)
 204 {
 205         struct shdma_chan *schan = to_shdma_chan(chan);
 206         struct shdma_dev *sdev = to_shdma_dev(schan->dma_chan.device);
 207         const struct shdma_ops *ops = sdev->ops;
 208         struct shdma_desc *desc;
 209         struct shdma_slave *slave = chan->private;
 210         int ret, i;
 211
 212         /*
 213          * This relies on the guarantee from dmaengine that alloc_chan_resources
 214          * never runs concurrently with itself or free_chan_resources.
 215          */
 216         if (slave) {
 217                 /* Legacy mode: .private is set in filter */
 218                 schan->real_slave_id = slave->slave_id;
 219                 ret = shdma_setup_slave(schan, 0);
 220                 if (ret < 0)
 221                         goto esetslave;
 222         } else {
 223                 /* Normal mode: real_slave_id was set by filter */
 224                 schan->slave_id = -EINVAL;
 225         }
 226
 227         schan->desc = kcalloc(NR_DESCS_PER_CHANNEL,
 228                               sdev->desc_size, GFP_KERNEL);
 229         if (!schan->desc) {
 230                 ret = -ENOMEM;
 231                 goto edescalloc;
 232         }
 233         schan->desc_num = NR_DESCS_PER_CHANNEL;
 234
 235         for (i = 0; i < NR_DESCS_PER_CHANNEL; i++) {
 236                 desc = ops->embedded_desc(schan->desc, i);
 237                 dma_async_tx_descriptor_init(&desc->async_tx,
 238                                              &schan->dma_chan);
 239                 desc->async_tx.tx_submit = shdma_tx_submit;
 240                 desc->mark = DESC_IDLE;
 241
 242                 list_add(&desc->node, &schan->ld_free);
 243         }
 244
 245         return NR_DESCS_PER_CHANNEL;
 246
 247 edescalloc:
 248         if (slave)
 249 esetslave:
 250                 clear_bit(slave->slave_id, shdma_slave_used);
 251         chan->private = NULL;
 252         return ret;
 253 }
 254
 255 /*
 256  * This is the standard shdma filter function to be used as a replacement to the
 257  * "old" method, using the .private pointer.
 258  * You always have to pass a valid slave id as the argument, old drivers that
 259  * pass ERR_PTR(-EINVAL) as a filter parameter and set it up in dma_slave_config
 260  * need to be updated so we can remove the slave_id field from dma_slave_config.
 261  * parameter. If this filter is used, the slave driver, after calling
 262  * dma_request_channel(), will also have to call dmaengine_slave_config() with
 263  * .direction, and either .src_addr or .dst_addr set.
 264  *
 265  * NOTE: this filter doesn't support multiple DMAC drivers with the DMA_SLAVE
 266  * capability! If this becomes a requirement, hardware glue drivers, using this
 267  * services would have to provide their own filters, which first would check
 268  * the device driver, similar to how other DMAC drivers, e.g., sa11x0-dma.c, do
 269  * this, and only then, in case of a match, call this common filter.
 270  * NOTE 2: This filter function is also used in the DT case by shdma_of_xlate().
 271  * In that case the MID-RID value is used for slave channel filtering and is
 272  * passed to this function in the "arg" parameter.
 273  */
 274 bool shdma_chan_filter(struct dma_chan *chan, void *arg)
 275 {
 276         struct shdma_chan *schan;
 277         struct shdma_dev *sdev;
 278         int slave_id = (long)arg;
 279         int ret;
 280
 281         /* Only support channels handled by this driver. */
 282         if (chan->device->device_alloc_chan_resources !=
 283             shdma_alloc_chan_resources)
 284                 return false;
 285
 286         schan = to_shdma_chan(chan);
 287         sdev = to_shdma_dev(chan->device);
 288
 289         /*
 290          * For DT, the schan->slave_id field is generated by the
 291          * set_slave function from the slave ID that is passed in
 292          * from xlate. For the non-DT case, the slave ID is
 293          * directly passed into the filter function by the driver
 294          */
 295         if (schan->dev->of_node) {
 296                 ret = sdev->ops->set_slave(schan, slave_id, 0, true);
 297                 if (ret < 0)
 298                         return false;
 299
 300                 schan->real_slave_id = schan->slave_id;
 301                 return true;
 302         }
 303
 304         if (slave_id < 0) {
 305                 /* No slave requested - arbitrary channel */
 306                 dev_warn(sdev->dma_dev.dev, "invalid slave ID passed to dma_request_slave\n");
 307                 return true;
 308         }
 309
 310         if (slave_id >= slave_num)
 311                 return false;
 312
 313         ret = sdev->ops->set_slave(schan, slave_id, 0, true);
 314         if (ret < 0)
 315                 return false;
 316
 317         schan->real_slave_id = slave_id;
 318
 319         return true;
 320 }
 321 EXPORT_SYMBOL(shdma_chan_filter);
 322
 323 static dma_async_tx_callback __ld_cleanup(struct shdma_chan *schan, bool all)
 324 {
 325         struct shdma_desc *desc, *_desc;
 326         /* Is the "exposed" head of a chain acked? */
 327         bool head_acked = false;
 328         dma_cookie_t cookie = 0;
 329         dma_async_tx_callback callback = NULL;
 330         struct dmaengine_desc_callback cb;
 331         unsigned long flags;
 332         LIST_HEAD(cyclic_list);
 333
 334         memset(&cb, 0, sizeof(cb));
 335         spin_lock_irqsave(&schan->chan_lock, flags);
 336         list_for_each_entry_safe(desc, _desc, &schan->ld_queue, node) {
 337                 struct dma_async_tx_descriptor *tx = &desc->async_tx;
 338
 339                 BUG_ON(tx->cookie > 0 && tx->cookie != desc->cookie);
 340                 BUG_ON(desc->mark != DESC_SUBMITTED &&
 341                        desc->mark != DESC_COMPLETED &&
 342                        desc->mark != DESC_WAITING);
 343
 344                 /*
 345                  * queue is ordered, and we use this loop to (1) clean up all
 346                  * completed descriptors, and to (2) update descriptor flags of
 347                  * any chunks in a (partially) completed chain
 348                  */
 349                 if (!all && desc->mark == DESC_SUBMITTED &&
 350                     desc->cookie != cookie)
 351                         break;
 352
 353                 if (tx->cookie > 0)
 354                         cookie = tx->cookie;
 355
 356                 if (desc->mark == DESC_COMPLETED && desc->chunks == 1) {
 357                         if (schan->dma_chan.completed_cookie != desc->cookie - 1)
 358                                 dev_dbg(schan->dev,
 359                                         "Completing cookie %d, expected %d\n",
 360                                         desc->cookie,
 361                                         schan->dma_chan.completed_cookie + 1);
 362                         schan->dma_chan.completed_cookie = desc->cookie;
 363                 }
 364
 365                 /* Call callback on the last chunk */
 366                 if (desc->mark == DESC_COMPLETED && tx->callback) {
 367                         desc->mark = DESC_WAITING;
 368                         dmaengine_desc_get_callback(tx, &cb);
 369                         callback = tx->callback;
 370                         dev_dbg(schan->dev, "descriptor #%d@%p on %d callback\n",
 371                                 tx->cookie, tx, schan->id);
 372                         BUG_ON(desc->chunks != 1);
 373                         break;
 374                 }
 375
 376                 if (tx->cookie > 0 || tx->cookie == -EBUSY) {
 377                         if (desc->mark == DESC_COMPLETED) {
 378                                 BUG_ON(tx->cookie < 0);
 379                                 desc->mark = DESC_WAITING;
 380                         }
 381                         head_acked = async_tx_test_ack(tx);
 382                 } else {
 383                         switch (desc->mark) {
 384                         case DESC_COMPLETED:
 385                                 desc->mark = DESC_WAITING;
 386                                 fallthrough;
 387                         case DESC_WAITING:
 388                                 if (head_acked)
 389                                         async_tx_ack(&desc->async_tx);
 390                         }
 391                 }
 392
 393                 dev_dbg(schan->dev, "descriptor %p #%d completed.\n",
 394                         tx, tx->cookie);
 395
 396                 if (((desc->mark == DESC_COMPLETED ||
 397                       desc->mark == DESC_WAITING) &&
 398                      async_tx_test_ack(&desc->async_tx)) || all) {
 399
 400                         if (all || !desc->cyclic) {
 401                                 /* Remove from ld_queue list */
 402                                 desc->mark = DESC_IDLE;
 403                                 list_move(&desc->node, &schan->ld_free);
 404                         } else {
 405                                 /* reuse as cyclic */
 406                                 desc->mark = DESC_SUBMITTED;
 407                                 list_move_tail(&desc->node, &cyclic_list);
 408                         }
 409
 410                         if (list_empty(&schan->ld_queue)) {
 411                                 dev_dbg(schan->dev, "Bring down channel %d\n", schan->id);
 412                                 pm_runtime_put(schan->dev);
 413                                 schan->pm_state = SHDMA_PM_ESTABLISHED;
 414                         } else if (schan->pm_state == SHDMA_PM_PENDING) {
 415                                 shdma_chan_xfer_ld_queue(schan);
 416                         }
 417                 }
 418         }
 419
 420         if (all && !callback)
 421                 /*
 422                  * Terminating and the loop completed normally: forgive
 423                  * uncompleted cookies
 424                  */
 425                 schan->dma_chan.completed_cookie = schan->dma_chan.cookie;
 426
 427         list_splice_tail(&cyclic_list, &schan->ld_queue);
 428
 429         spin_unlock_irqrestore(&schan->chan_lock, flags);
 430
 431         dmaengine_desc_callback_invoke(&cb, NULL);
 432
 433         return callback;
 434 }
 435
 436 /*
 437  * shdma_chan_ld_cleanup - Clean up link descriptors
 438  *
 439  * Clean up the ld_queue of DMA channel.
 440  */
 441 static void shdma_chan_ld_cleanup(struct shdma_chan *schan, bool all)
 442 {
 443         while (__ld_cleanup(schan, all))
 444                 ;
 445 }
 446
 447 /*
 448  * shdma_free_chan_resources - Free all resources of the channel.
 449  */
 450 static void shdma_free_chan_resources(struct dma_chan *chan)
 451 {
 452         struct shdma_chan *schan = to_shdma_chan(chan);
 453         struct shdma_dev *sdev = to_shdma_dev(chan->device);
 454         const struct shdma_ops *ops = sdev->ops;
 455         LIST_HEAD(list);
 456
 457         /* Protect against ISR */
 458         spin_lock_irq(&schan->chan_lock);
 459         ops->halt_channel(schan);
 460         spin_unlock_irq(&schan->chan_lock);
 461
 462         /* Now no new interrupts will occur */
 463
 464         /* Prepared and not submitted descriptors can still be on the queue */
 465         if (!list_empty(&schan->ld_queue))
 466                 shdma_chan_ld_cleanup(schan, true);
 467
 468         if (schan->slave_id >= 0) {
 469                 /* The caller is holding dma_list_mutex */
 470                 clear_bit(schan->slave_id, shdma_slave_used);
 471                 chan->private = NULL;
 472         }
 473
 474         schan->real_slave_id = 0;
 475
 476         spin_lock_irq(&schan->chan_lock);
 477
 478         list_splice_init(&schan->ld_free, &list);
 479         schan->desc_num = 0;
 480
 481         spin_unlock_irq(&schan->chan_lock);
 482
 483         kfree(schan->desc);
 484 }
 485
 486 /**
 487  * shdma_add_desc - get, set up and return one transfer descriptor
 488  * @schan:      DMA channel
 489  * @flags:      DMA transfer flags
 490  * @dst:        destination DMA address, incremented when direction equals
 491  *              DMA_DEV_TO_MEM or DMA_MEM_TO_MEM
 492  * @src:        source DMA address, incremented when direction equals
 493  *              DMA_MEM_TO_DEV or DMA_MEM_TO_MEM
 494  * @len:        DMA transfer length
 495  * @first:      if NULL, set to the current descriptor and cookie set to -EBUSY
 496  * @direction:  needed for slave DMA to decide which address to keep constant,
 497  *              equals DMA_MEM_TO_MEM for MEMCPY
 498  * Returns 0 or an error
 499  * Locks: called with desc_lock held
 500  */
 501 static struct shdma_desc *shdma_add_desc(struct shdma_chan *schan,
 502         unsigned long flags, dma_addr_t *dst, dma_addr_t *src, size_t *len,
 503         struct shdma_desc **first, enum dma_transfer_direction direction)
 504 {
 505         struct shdma_dev *sdev = to_shdma_dev(schan->dma_chan.device);
 506         const struct shdma_ops *ops = sdev->ops;
 507         struct shdma_desc *new;
 508         size_t copy_size = *len;
 509
 510         if (!copy_size)
 511                 return NULL;
 512
 513         /* Allocate the link descriptor from the free list */
 514         new = shdma_get_desc(schan);
 515         if (!new) {
 516                 dev_err(schan->dev, "No free link descriptor available\n");
 517                 return NULL;
 518         }
 519
 520         ops->desc_setup(schan, new, *src, *dst, &copy_size);
 521
 522         if (!*first) {
 523                 /* First desc */
 524                 new->async_tx.cookie = -EBUSY;
 525                 *first = new;
 526         } else {
 527                 /* Other desc - invisible to the user */
 528                 new->async_tx.cookie = -EINVAL;
 529         }
 530
 531         dev_dbg(schan->dev,
 532                 "chaining (%zu/%zu)@%pad -> %pad with %p, cookie %d\n",
 533                 copy_size, *len, src, dst, &new->async_tx,
 534                 new->async_tx.cookie);
 535
 536         new->mark = DESC_PREPARED;
 537         new->async_tx.flags = flags;
 538         new->direction = direction;
 539         new->partial = 0;
 540
 541         *len -= copy_size;
 542         if (direction == DMA_MEM_TO_MEM || direction == DMA_MEM_TO_DEV)
 543                 *src += copy_size;
 544         if (direction == DMA_MEM_TO_MEM || direction == DMA_DEV_TO_MEM)
 545                 *dst += copy_size;
 546
 547         return new;
 548 }
 549
 550 /*
 551  * shdma_prep_sg - prepare transfer descriptors from an SG list
 552  *
 553  * Common routine for public (MEMCPY) and slave DMA. The MEMCPY case is also
 554  * converted to scatter-gather to guarantee consistent locking and a correct
 555  * list manipulation. For slave DMA direction carries the usual meaning, and,
 556  * logically, the SG list is RAM and the addr variable contains slave address,
 557  * e.g., the FIFO I/O register. For MEMCPY direction equals DMA_MEM_TO_MEM
 558  * and the SG list contains only one element and points at the source buffer.
 559  */
 560 static struct dma_async_tx_descriptor *shdma_prep_sg(struct shdma_chan *schan,
 561         struct scatterlist *sgl, unsigned int sg_len, dma_addr_t *addr,
 562         enum dma_transfer_direction direction, unsigned long flags, bool cyclic)
 563 {
 564         struct scatterlist *sg;
 565         struct shdma_desc *first = NULL, *new = NULL /* compiler... */;
 566         LIST_HEAD(tx_list);
 567         int chunks = 0;
 568         unsigned long irq_flags;
 569         int i;
 570
 571         for_each_sg(sgl, sg, sg_len, i)
 572                 chunks += DIV_ROUND_UP(sg_dma_len(sg), schan->max_xfer_len);
 573
 574         /* Have to lock the whole loop to protect against concurrent release */
 575         spin_lock_irqsave(&schan->chan_lock, irq_flags);
 576
 577         /*
 578          * Chaining:
 579          * first descriptor is what user is dealing with in all API calls, its
 580          *      cookie is at first set to -EBUSY, at tx-submit to a positive
 581          *      number
 582          * if more than one chunk is needed further chunks have cookie = -EINVAL
 583          * the last chunk, if not equal to the first, has cookie = -ENOSPC
 584          * all chunks are linked onto the tx_list head with their .node heads
 585          *      only during this function, then they are immediately spliced
 586          *      back onto the free list in form of a chain
 587          */
 588         for_each_sg(sgl, sg, sg_len, i) {
 589                 dma_addr_t sg_addr = sg_dma_address(sg);
 590                 size_t len = sg_dma_len(sg);
 591
 592                 if (!len)
 593                         goto err_get_desc;
 594
 595                 do {
 596                         dev_dbg(schan->dev, "Add SG #%d@%p[%zu], dma %pad\n",
 597                                 i, sg, len, &sg_addr);
 598
 599                         if (direction == DMA_DEV_TO_MEM)
 600                                 new = shdma_add_desc(schan, flags,
 601                                                 &sg_addr, addr, &len, &first,
 602                                                 direction);
 603                         else
 604                                 new = shdma_add_desc(schan, flags,
 605                                                 addr, &sg_addr, &len, &first,
 606                                                 direction);
 607                         if (!new)
 608                                 goto err_get_desc;
 609
 610                         new->cyclic = cyclic;
 611                         if (cyclic)
 612                                 new->chunks = 1;
 613                         else
 614                                 new->chunks = chunks--;
 615                         list_add_tail(&new->node, &tx_list);
 616                 } while (len);
 617         }
 618
 619         if (new != first)
 620                 new->async_tx.cookie = -ENOSPC;
 621
 622         /* Put them back on the free list, so, they don't get lost */
 623         list_splice_tail(&tx_list, &schan->ld_free);
 624
 625         spin_unlock_irqrestore(&schan->chan_lock, irq_flags);
 626
 627         return &first->async_tx;
 628
 629 err_get_desc:
 630         list_for_each_entry(new, &tx_list, node)
 631                 new->mark = DESC_IDLE;
 632         list_splice(&tx_list, &schan->ld_free);
 633
 634         spin_unlock_irqrestore(&schan->chan_lock, irq_flags);
 635
 636         return NULL;
 637 }
 638
 639 static struct dma_async_tx_descriptor *shdma_prep_memcpy(
 640         struct dma_chan *chan, dma_addr_t dma_dest, dma_addr_t dma_src,
 641         size_t len, unsigned long flags)
 642 {
 643         struct shdma_chan *schan = to_shdma_chan(chan);
 644         struct scatterlist sg;
 645
 646         if (!chan || !len)
 647                 return NULL;
 648
 649         BUG_ON(!schan->desc_num);
 650
 651         sg_init_table(&sg, 1);
 652         sg_set_page(&sg, pfn_to_page(PFN_DOWN(dma_src)), len,
 653                     offset_in_page(dma_src));
 654         sg_dma_address(&sg) = dma_src;
 655         sg_dma_len(&sg) = len;
 656
 657         return shdma_prep_sg(schan, &sg, 1, &dma_dest, DMA_MEM_TO_MEM,
 658                              flags, false);
 659 }
 660
 661 static struct dma_async_tx_descriptor *shdma_prep_slave_sg(
 662         struct dma_chan *chan, struct scatterlist *sgl, unsigned int sg_len,
 663         enum dma_transfer_direction direction, unsigned long flags, void *context)
 664 {
 665         struct shdma_chan *schan = to_shdma_chan(chan);
 666         struct shdma_dev *sdev = to_shdma_dev(schan->dma_chan.device);
 667         const struct shdma_ops *ops = sdev->ops;
 668         int slave_id = schan->slave_id;
 669         dma_addr_t slave_addr;
 670
 671         if (!chan)
 672                 return NULL;
 673
 674         BUG_ON(!schan->desc_num);
 675
 676         /* Someone calling slave DMA on a generic channel? */
 677         if (slave_id < 0 || !sg_len) {
 678                 dev_warn(schan->dev, "%s: bad parameter: len=%d, id=%d\n",
 679                          __func__, sg_len, slave_id);
 680                 return NULL;
 681         }
 682
 683         slave_addr = ops->slave_addr(schan);
 684
 685         return shdma_prep_sg(schan, sgl, sg_len, &slave_addr,
 686                              direction, flags, false);
 687 }
 688
 689 #define SHDMA_MAX_SG_LEN 32
 690
 691 static struct dma_async_tx_descriptor *shdma_prep_dma_cyclic(
 692         struct dma_chan *chan, dma_addr_t buf_addr, size_t buf_len,
 693         size_t period_len, enum dma_transfer_direction direction,
 694         unsigned long flags)
 695 {
 696         struct shdma_chan *schan = to_shdma_chan(chan);
 697         struct shdma_dev *sdev = to_shdma_dev(schan->dma_chan.device);
 698         struct dma_async_tx_descriptor *desc;
 699         const struct shdma_ops *ops = sdev->ops;
 700         unsigned int sg_len = buf_len / period_len;
 701         int slave_id = schan->slave_id;
 702         dma_addr_t slave_addr;
 703         struct scatterlist *sgl;
 704         int i;
 705
 706         if (!chan)
 707                 return NULL;
 708
 709         BUG_ON(!schan->desc_num);
 710
 711         if (sg_len > SHDMA_MAX_SG_LEN) {
 712                 dev_err(schan->dev, "sg length %d exceeds limit %d",
 713                                 sg_len, SHDMA_MAX_SG_LEN);
 714                 return NULL;
 715         }
 716
 717         /* Someone calling slave DMA on a generic channel? */
 718         if (slave_id < 0 || (buf_len < period_len)) {
 719                 dev_warn(schan->dev,
 720                         "%s: bad parameter: buf_len=%zu, period_len=%zu, id=%d\n",
 721                         __func__, buf_len, period_len, slave_id);
 722                 return NULL;
 723         }
 724
 725         slave_addr = ops->slave_addr(schan);
 726
 727         /*
 728          * Allocate the sg list dynamically as it would consumer too much stack
 729          * space.
 730          */
 731         sgl = kcalloc(sg_len, sizeof(*sgl), GFP_KERNEL);
 732         if (!sgl)
 733                 return NULL;
 734
 735         sg_init_table(sgl, sg_len);
 736
 737         for (i = 0; i < sg_len; i++) {
 738                 dma_addr_t src = buf_addr + (period_len * i);
 739
 740                 sg_set_page(&sgl[i], pfn_to_page(PFN_DOWN(src)), period_len,
 741                             offset_in_page(src));
 742                 sg_dma_address(&sgl[i]) = src;
 743                 sg_dma_len(&sgl[i]) = period_len;
 744         }
 745
 746         desc = shdma_prep_sg(schan, sgl, sg_len, &slave_addr,
 747                              direction, flags, true);
 748
 749         kfree(sgl);
 750         return desc;
 751 }
 752
 753 static int shdma_terminate_all(struct dma_chan *chan)
 754 {
 755         struct shdma_chan *schan = to_shdma_chan(chan);
 756         struct shdma_dev *sdev = to_shdma_dev(chan->device);
 757         const struct shdma_ops *ops = sdev->ops;
 758         unsigned long flags;
 759
 760         spin_lock_irqsave(&schan->chan_lock, flags);
 761         ops->halt_channel(schan);
 762
 763         if (ops->get_partial && !list_empty(&schan->ld_queue)) {
 764                 /* Record partial transfer */
 765                 struct shdma_desc *desc = list_first_entry(&schan->ld_queue,
 766                                                            struct shdma_desc, node);
 767                 desc->partial = ops->get_partial(schan, desc);
 768         }
 769
 770         spin_unlock_irqrestore(&schan->chan_lock, flags);
 771
 772         shdma_chan_ld_cleanup(schan, true);
 773
 774         return 0;
 775 }
 776
 777 static int shdma_config(struct dma_chan *chan,
 778                         struct dma_slave_config *config)
 779 {
 780         struct shdma_chan *schan = to_shdma_chan(chan);
 781
 782         /*
 783          * So far only .slave_id is used, but the slave drivers are
 784          * encouraged to also set a transfer direction and an address.
 785          */
 786         if (!config)
 787                 return -EINVAL;
 788
 789         /*
 790          * overriding the slave_id through dma_slave_config is deprecated,
 791          * but possibly some out-of-tree drivers still do it.
 792          */
 793         if (WARN_ON_ONCE(config->slave_id &&
 794                          config->slave_id != schan->real_slave_id))
 795                 schan->real_slave_id = config->slave_id;
 796
 797         /*
 798          * We could lock this, but you shouldn't be configuring the
 799          * channel, while using it...
 800          */
 801         return shdma_setup_slave(schan,
 802                                  config->direction == DMA_DEV_TO_MEM ?
 803                                  config->src_addr : config->dst_addr);
 804 }
 805
 806 static void shdma_issue_pending(struct dma_chan *chan)
 807 {
 808         struct shdma_chan *schan = to_shdma_chan(chan);
 809
 810         spin_lock_irq(&schan->chan_lock);
 811         if (schan->pm_state == SHDMA_PM_ESTABLISHED)
 812                 shdma_chan_xfer_ld_queue(schan);
 813         else
 814                 schan->pm_state = SHDMA_PM_PENDING;
 815         spin_unlock_irq(&schan->chan_lock);
 816 }
 817
 818 static enum dma_status shdma_tx_status(struct dma_chan *chan,
 819                                         dma_cookie_t cookie,
 820                                         struct dma_tx_state *txstate)
 821 {
 822         struct shdma_chan *schan = to_shdma_chan(chan);
 823         enum dma_status status;
 824         unsigned long flags;
 825
 826         shdma_chan_ld_cleanup(schan, false);
 827
 828         spin_lock_irqsave(&schan->chan_lock, flags);
 829
 830         status = dma_cookie_status(chan, cookie, txstate);
 831
 832         /*
 833          * If we don't find cookie on the queue, it has been aborted and we have
 834          * to report error
 835          */
 836         if (status != DMA_COMPLETE) {
 837                 struct shdma_desc *sdesc;
 838                 status = DMA_ERROR;
 839                 list_for_each_entry(sdesc, &schan->ld_queue, node)
 840                         if (sdesc->cookie == cookie) {
 841                                 status = DMA_IN_PROGRESS;
 842                                 break;
 843                         }
 844         }
 845
 846         spin_unlock_irqrestore(&schan->chan_lock, flags);
 847
 848         return status;
 849 }
 850
 851 /* Called from error IRQ or NMI */
 852 bool shdma_reset(struct shdma_dev *sdev)
 853 {
 854         const struct shdma_ops *ops = sdev->ops;
 855         struct shdma_chan *schan;
 856         unsigned int handled = 0;
 857         int i;
 858
 859         /* Reset all channels */
 860         shdma_for_each_chan(schan, sdev, i) {
 861                 struct shdma_desc *sdesc;
 862                 LIST_HEAD(dl);
 863
 864                 if (!schan)
 865                         continue;
 866
 867                 spin_lock(&schan->chan_lock);
 868
 869                 /* Stop the channel */
 870                 ops->halt_channel(schan);
 871
 872                 list_splice_init(&schan->ld_queue, &dl);
 873
 874                 if (!list_empty(&dl)) {
 875                         dev_dbg(schan->dev, "Bring down channel %d\n", schan->id);
 876                         pm_runtime_put(schan->dev);
 877                 }
 878                 schan->pm_state = SHDMA_PM_ESTABLISHED;
 879
 880                 spin_unlock(&schan->chan_lock);
 881
 882                 /* Complete all  */
 883                 list_for_each_entry(sdesc, &dl, node) {
 884                         struct dma_async_tx_descriptor *tx = &sdesc->async_tx;
 885
 886                         sdesc->mark = DESC_IDLE;
 887                         dmaengine_desc_get_callback_invoke(tx, NULL);
 888                 }
 889
 890                 spin_lock(&schan->chan_lock);
 891                 list_splice(&dl, &schan->ld_free);
 892                 spin_unlock(&schan->chan_lock);
 893
 894                 handled++;
 895         }
 896
 897         return !!handled;
 898 }
 899 EXPORT_SYMBOL(shdma_reset);
 900
 901 static irqreturn_t chan_irq(int irq, void *dev)
 902 {
 903         struct shdma_chan *schan = dev;
 904         const struct shdma_ops *ops =
 905                 to_shdma_dev(schan->dma_chan.device)->ops;
 906         irqreturn_t ret;
 907
 908         spin_lock(&schan->chan_lock);
 909
 910         ret = ops->chan_irq(schan, irq) ? IRQ_WAKE_THREAD : IRQ_NONE;
 911
 912         spin_unlock(&schan->chan_lock);
 913
 914         return ret;
 915 }
 916
 917 static irqreturn_t chan_irqt(int irq, void *dev)
 918 {
 919         struct shdma_chan *schan = dev;
 920         const struct shdma_ops *ops =
 921                 to_shdma_dev(schan->dma_chan.device)->ops;
 922         struct shdma_desc *sdesc;
 923
 924         spin_lock_irq(&schan->chan_lock);
 925         list_for_each_entry(sdesc, &schan->ld_queue, node) {
 926                 if (sdesc->mark == DESC_SUBMITTED &&
 927                     ops->desc_completed(schan, sdesc)) {
 928                         dev_dbg(schan->dev, "done #%d@%p\n",
 929                                 sdesc->async_tx.cookie, &sdesc->async_tx);
 930                         sdesc->mark = DESC_COMPLETED;
 931                         break;
 932                 }
 933         }
 934         /* Next desc */
 935         shdma_chan_xfer_ld_queue(schan);
 936         spin_unlock_irq(&schan->chan_lock);
 937
 938         shdma_chan_ld_cleanup(schan, false);
 939
 940         return IRQ_HANDLED;
 941 }
 942
 943 int shdma_request_irq(struct shdma_chan *schan, int irq,
 944                            unsigned long flags, const char *name)
 945 {
 946         int ret = devm_request_threaded_irq(schan->dev, irq, chan_irq,
 947                                             chan_irqt, flags, name, schan);
 948
 949         schan->irq = ret < 0 ? ret : irq;
 950
 951         return ret;
 952 }
 953 EXPORT_SYMBOL(shdma_request_irq);
 954
 955 void shdma_chan_probe(struct shdma_dev *sdev,
 956                            struct shdma_chan *schan, int id)
 957 {
 958         schan->pm_state = SHDMA_PM_ESTABLISHED;
 959
 960         /* reference struct dma_device */
 961         schan->dma_chan.device = &sdev->dma_dev;
 962         dma_cookie_init(&schan->dma_chan);
 963
 964         schan->dev = sdev->dma_dev.dev;
 965         schan->id = id;
 966
 967         if (!schan->max_xfer_len)
 968                 schan->max_xfer_len = PAGE_SIZE;
 969
 970         spin_lock_init(&schan->chan_lock);
 971
 972         /* Init descripter manage list */
 973         INIT_LIST_HEAD(&schan->ld_queue);
 974         INIT_LIST_HEAD(&schan->ld_free);
 975
 976         /* Add the channel to DMA device channel list */
 977         list_add_tail(&schan->dma_chan.device_node,
 978                         &sdev->dma_dev.channels);
 979         sdev->schan[id] = schan;
 980 }
 981 EXPORT_SYMBOL(shdma_chan_probe);
 982
 983 void shdma_chan_remove(struct shdma_chan *schan)
 984 {
 985         list_del(&schan->dma_chan.device_node);
 986 }
 987 EXPORT_SYMBOL(shdma_chan_remove);
 988
 989 int shdma_init(struct device *dev, struct shdma_dev *sdev,
 990                     int chan_num)
 991 {
 992         struct dma_device *dma_dev = &sdev->dma_dev;
 993
 994         /*
 995          * Require all call-backs for now, they can trivially be made optional
 996          * later as required
 997          */
 998         if (!sdev->ops ||
 999             !sdev->desc_size ||
1000             !sdev->ops->embedded_desc ||
1001             !sdev->ops->start_xfer ||
1002             !sdev->ops->setup_xfer ||
1003             !sdev->ops->set_slave ||
1004             !sdev->ops->desc_setup ||
1005             !sdev->ops->slave_addr ||
1006             !sdev->ops->channel_busy ||
1007             !sdev->ops->halt_channel ||
1008             !sdev->ops->desc_completed)
1009                 return -EINVAL;
1010
1011         sdev->schan = kcalloc(chan_num, sizeof(*sdev->schan), GFP_KERNEL);
1012         if (!sdev->schan)
1013                 return -ENOMEM;
1014
1015         INIT_LIST_HEAD(&dma_dev->channels);
1016
1017         /* Common and MEMCPY operations */
1018         dma_dev->device_alloc_chan_resources
1019                 = shdma_alloc_chan_resources;
1020         dma_dev->device_free_chan_resources = shdma_free_chan_resources;
1021         dma_dev->device_prep_dma_memcpy = shdma_prep_memcpy;
1022         dma_dev->device_tx_status = shdma_tx_status;
1023         dma_dev->device_issue_pending = shdma_issue_pending;
1024
1025         /* Compulsory for DMA_SLAVE fields */
1026         dma_dev->device_prep_slave_sg = shdma_prep_slave_sg;
1027         dma_dev->device_prep_dma_cyclic = shdma_prep_dma_cyclic;
1028         dma_dev->device_config = shdma_config;
1029         dma_dev->device_terminate_all = shdma_terminate_all;
1030
1031         dma_dev->dev = dev;
1032
1033         return 0;
1034 }
1035 EXPORT_SYMBOL(shdma_init);
1036
1037 void shdma_cleanup(struct shdma_dev *sdev)
1038 {
1039         kfree(sdev->schan);
1040 }
1041 EXPORT_SYMBOL(shdma_cleanup);
1042
1043 static int __init shdma_enter(void)
1044 {
1045         shdma_slave_used = kcalloc(DIV_ROUND_UP(slave_num, BITS_PER_LONG),
1046                                    sizeof(long),
1047                                    GFP_KERNEL);
1048         if (!shdma_slave_used)
1049                 return -ENOMEM;
1050         return 0;
1051 }
1052 module_init(shdma_enter);
1053
1054 static void __exit shdma_exit(void)
1055 {
1056         kfree(shdma_slave_used);
1057 }
1058 module_exit(shdma_exit);
1059
1060 MODULE_LICENSE("GPL v2");
1061 MODULE_DESCRIPTION("SH-DMA driver base library");
1062 MODULE_AUTHOR("Guennadi Liakhovetski <g.liakhovetski@gmx.de>");