1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 * Driver for the Atmel AHB DMA Controller (aka HDMA or DMAC on AT91 systems)
   4 *
   5 * Copyright (C) 2008 Atmel Corporation
   6 *
   7 * This supports the Atmel AHB DMA Controller found in several Atmel SoCs.
   8 * The only Atmel DMA Controller that is not covered by this driver is the one
   9 * found on AT91SAM9263.
  10 */
  11
  12#include <dt-bindings/dma/at91.h>
  13#include <linux/clk.h>
  14#include <linux/dmaengine.h>
  15#include <linux/dma-mapping.h>
  16#include <linux/dmapool.h>
  17#include <linux/interrupt.h>
  18#include <linux/module.h>
  19#include <linux/platform_device.h>
  20#include <linux/slab.h>
  21#include <linux/of.h>
  22#include <linux/of_device.h>
  23#include <linux/of_dma.h>
  24
  25#include "at_hdmac_regs.h"
  26#include "dmaengine.h"
  27
  28/*
  29 * Glossary
  30 * --------
  31 *
  32 * at_hdmac		: Name of the ATmel AHB DMA Controller
  33 * at_dma_ / atdma	: ATmel DMA controller entity related
  34 * atc_	/ atchan	: ATmel DMA Channel entity related
  35 */
  36
  37#define	ATC_DEFAULT_CFG		(ATC_FIFOCFG_HALFFIFO)
  38#define	ATC_DEFAULT_CTRLB	(ATC_SIF(AT_DMA_MEM_IF) \
  39				|ATC_DIF(AT_DMA_MEM_IF))
  40#define ATC_DMA_BUSWIDTHS\
  41	(BIT(DMA_SLAVE_BUSWIDTH_UNDEFINED) |\
  42	BIT(DMA_SLAVE_BUSWIDTH_1_BYTE) |\
  43	BIT(DMA_SLAVE_BUSWIDTH_2_BYTES) |\
  44	BIT(DMA_SLAVE_BUSWIDTH_4_BYTES))
  45
  46#define ATC_MAX_DSCR_TRIALS	10
  47
  48/*
  49 * Initial number of descriptors to allocate for each channel. This could
  50 * be increased during dma usage.
  51 */
  52static unsigned int init_nr_desc_per_channel = 64;
  53module_param(init_nr_desc_per_channel, uint, 0644);
  54MODULE_PARM_DESC(init_nr_desc_per_channel,
  55		 "initial descriptors per channel (default: 64)");
  56
  57
  58/* prototypes */
  59static dma_cookie_t atc_tx_submit(struct dma_async_tx_descriptor *tx);
  60static void atc_issue_pending(struct dma_chan *chan);
  61
  62
  63/*----------------------------------------------------------------------*/
  64
  65static inline unsigned int atc_get_xfer_width(dma_addr_t src, dma_addr_t dst,
  66						size_t len)
  67{
  68	unsigned int width;
  69
  70	if (!((src | dst  | len) & 3))
  71		width = 2;
  72	else if (!((src | dst | len) & 1))
  73		width = 1;
  74	else
  75		width = 0;
  76
  77	return width;
  78}
  79
  80static struct at_desc *atc_first_active(struct at_dma_chan *atchan)
  81{
  82	return list_first_entry(&atchan->active_list,
  83				struct at_desc, desc_node);
  84}
  85
  86static struct at_desc *atc_first_queued(struct at_dma_chan *atchan)
  87{
  88	return list_first_entry(&atchan->queue,
  89				struct at_desc, desc_node);
  90}
  91
  92/**
  93 * atc_alloc_descriptor - allocate and return an initialized descriptor
  94 * @chan: the channel to allocate descriptors for
  95 * @gfp_flags: GFP allocation flags
  96 *
  97 * Note: The ack-bit is positioned in the descriptor flag at creation time
  98 *       to make initial allocation more convenient. This bit will be cleared
  99 *       and control will be given to client at usage time (during
 100 *       preparation functions).
 101 */
 102static struct at_desc *atc_alloc_descriptor(struct dma_chan *chan,
 103					    gfp_t gfp_flags)
 104{
 105	struct at_desc	*desc = NULL;
 106	struct at_dma	*atdma = to_at_dma(chan->device);
 107	dma_addr_t phys;
 108
 109	desc = dma_pool_zalloc(atdma->dma_desc_pool, gfp_flags, &phys);
 110	if (desc) {
 111		INIT_LIST_HEAD(&desc->tx_list);
 112		dma_async_tx_descriptor_init(&desc->txd, chan);
 113		/* txd.flags will be overwritten in prep functions */
 114		desc->txd.flags = DMA_CTRL_ACK;
 115		desc->txd.tx_submit = atc_tx_submit;
 116		desc->txd.phys = phys;
 117	}
 118
 119	return desc;
 120}
 121
 122/**
 123 * atc_desc_get - get an unused descriptor from free_list
 124 * @atchan: channel we want a new descriptor for
 125 */
 126static struct at_desc *atc_desc_get(struct at_dma_chan *atchan)
 127{
 128	struct at_desc *desc, *_desc;
 129	struct at_desc *ret = NULL;
 130	unsigned long flags;
 131	unsigned int i = 0;
 132
 133	spin_lock_irqsave(&atchan->lock, flags);
 134	list_for_each_entry_safe(desc, _desc, &atchan->free_list, desc_node) {
 135		i++;
 136		if (async_tx_test_ack(&desc->txd)) {
 137			list_del(&desc->desc_node);
 138			ret = desc;
 139			break;
 140		}
 141		dev_dbg(chan2dev(&atchan->chan_common),
 142				"desc %p not ACKed\n", desc);
 143	}
 144	spin_unlock_irqrestore(&atchan->lock, flags);
 145	dev_vdbg(chan2dev(&atchan->chan_common),
 146		"scanned %u descriptors on freelist\n", i);
 147
 148	/* no more descriptor available in initial pool: create one more */
 149	if (!ret)
 150		ret = atc_alloc_descriptor(&atchan->chan_common, GFP_NOWAIT);
 
 
 
 
 
 
 
 
 
 151
 152	return ret;
 153}
 154
 155/**
 156 * atc_desc_put - move a descriptor, including any children, to the free list
 157 * @atchan: channel we work on
 158 * @desc: descriptor, at the head of a chain, to move to free list
 159 */
 160static void atc_desc_put(struct at_dma_chan *atchan, struct at_desc *desc)
 161{
 162	if (desc) {
 163		struct at_desc *child;
 164		unsigned long flags;
 165
 166		spin_lock_irqsave(&atchan->lock, flags);
 167		list_for_each_entry(child, &desc->tx_list, desc_node)
 168			dev_vdbg(chan2dev(&atchan->chan_common),
 169					"moving child desc %p to freelist\n",
 170					child);
 171		list_splice_init(&desc->tx_list, &atchan->free_list);
 172		dev_vdbg(chan2dev(&atchan->chan_common),
 173			 "moving desc %p to freelist\n", desc);
 174		list_add(&desc->desc_node, &atchan->free_list);
 175		spin_unlock_irqrestore(&atchan->lock, flags);
 176	}
 177}
 178
 179/**
 180 * atc_desc_chain - build chain adding a descriptor
 181 * @first: address of first descriptor of the chain
 182 * @prev: address of previous descriptor of the chain
 183 * @desc: descriptor to queue
 184 *
 185 * Called from prep_* functions
 186 */
 187static void atc_desc_chain(struct at_desc **first, struct at_desc **prev,
 188			   struct at_desc *desc)
 189{
 190	if (!(*first)) {
 191		*first = desc;
 192	} else {
 193		/* inform the HW lli about chaining */
 194		(*prev)->lli.dscr = desc->txd.phys;
 195		/* insert the link descriptor to the LD ring */
 196		list_add_tail(&desc->desc_node,
 197				&(*first)->tx_list);
 198	}
 199	*prev = desc;
 200}
 201
 202/**
 203 * atc_dostart - starts the DMA engine for real
 204 * @atchan: the channel we want to start
 205 * @first: first descriptor in the list we want to begin with
 206 *
 207 * Called with atchan->lock held and bh disabled
 208 */
 209static void atc_dostart(struct at_dma_chan *atchan, struct at_desc *first)
 210{
 211	struct at_dma	*atdma = to_at_dma(atchan->chan_common.device);
 212
 213	/* ASSERT:  channel is idle */
 214	if (atc_chan_is_enabled(atchan)) {
 215		dev_err(chan2dev(&atchan->chan_common),
 216			"BUG: Attempted to start non-idle channel\n");
 217		dev_err(chan2dev(&atchan->chan_common),
 218			"  channel: s0x%x d0x%x ctrl0x%x:0x%x l0x%x\n",
 219			channel_readl(atchan, SADDR),
 220			channel_readl(atchan, DADDR),
 221			channel_readl(atchan, CTRLA),
 222			channel_readl(atchan, CTRLB),
 223			channel_readl(atchan, DSCR));
 224
 225		/* The tasklet will hopefully advance the queue... */
 226		return;
 227	}
 228
 229	vdbg_dump_regs(atchan);
 230
 231	channel_writel(atchan, SADDR, 0);
 232	channel_writel(atchan, DADDR, 0);
 233	channel_writel(atchan, CTRLA, 0);
 234	channel_writel(atchan, CTRLB, 0);
 235	channel_writel(atchan, DSCR, first->txd.phys);
 236	channel_writel(atchan, SPIP, ATC_SPIP_HOLE(first->src_hole) |
 237		       ATC_SPIP_BOUNDARY(first->boundary));
 238	channel_writel(atchan, DPIP, ATC_DPIP_HOLE(first->dst_hole) |
 239		       ATC_DPIP_BOUNDARY(first->boundary));
 240	dma_writel(atdma, CHER, atchan->mask);
 241
 242	vdbg_dump_regs(atchan);
 243}
 244
 245/*
 246 * atc_get_desc_by_cookie - get the descriptor of a cookie
 247 * @atchan: the DMA channel
 248 * @cookie: the cookie to get the descriptor for
 249 */
 250static struct at_desc *atc_get_desc_by_cookie(struct at_dma_chan *atchan,
 251						dma_cookie_t cookie)
 252{
 253	struct at_desc *desc, *_desc;
 254
 255	list_for_each_entry_safe(desc, _desc, &atchan->queue, desc_node) {
 256		if (desc->txd.cookie == cookie)
 257			return desc;
 258	}
 259
 260	list_for_each_entry_safe(desc, _desc, &atchan->active_list, desc_node) {
 261		if (desc->txd.cookie == cookie)
 262			return desc;
 263	}
 264
 265	return NULL;
 266}
 267
 268/**
 269 * atc_calc_bytes_left - calculates the number of bytes left according to the
 270 * value read from CTRLA.
 271 *
 272 * @current_len: the number of bytes left before reading CTRLA
 273 * @ctrla: the value of CTRLA
 274 */
 275static inline int atc_calc_bytes_left(int current_len, u32 ctrla)
 276{
 277	u32 btsize = (ctrla & ATC_BTSIZE_MAX);
 278	u32 src_width = ATC_REG_TO_SRC_WIDTH(ctrla);
 279
 280	/*
 281	 * According to the datasheet, when reading the Control A Register
 282	 * (ctrla), the Buffer Transfer Size (btsize) bitfield refers to the
 283	 * number of transfers completed on the Source Interface.
 284	 * So btsize is always a number of source width transfers.
 285	 */
 286	return current_len - (btsize << src_width);
 287}
 288
 289/**
 290 * atc_get_bytes_left - get the number of bytes residue for a cookie
 291 * @chan: DMA channel
 292 * @cookie: transaction identifier to check status of
 293 */
 294static int atc_get_bytes_left(struct dma_chan *chan, dma_cookie_t cookie)
 295{
 296	struct at_dma_chan      *atchan = to_at_dma_chan(chan);
 297	struct at_desc *desc_first = atc_first_active(atchan);
 298	struct at_desc *desc;
 299	int ret;
 300	u32 ctrla, dscr, trials;
 301
 302	/*
 303	 * If the cookie doesn't match to the currently running transfer then
 304	 * we can return the total length of the associated DMA transfer,
 305	 * because it is still queued.
 306	 */
 307	desc = atc_get_desc_by_cookie(atchan, cookie);
 308	if (desc == NULL)
 309		return -EINVAL;
 310	else if (desc != desc_first)
 311		return desc->total_len;
 312
 313	/* cookie matches to the currently running transfer */
 314	ret = desc_first->total_len;
 315
 316	if (desc_first->lli.dscr) {
 317		/* hardware linked list transfer */
 318
 319		/*
 320		 * Calculate the residue by removing the length of the child
 321		 * descriptors already transferred from the total length.
 322		 * To get the current child descriptor we can use the value of
 323		 * the channel's DSCR register and compare it against the value
 324		 * of the hardware linked list structure of each child
 325		 * descriptor.
 326		 *
 327		 * The CTRLA register provides us with the amount of data
 328		 * already read from the source for the current child
 329		 * descriptor. So we can compute a more accurate residue by also
 330		 * removing the number of bytes corresponding to this amount of
 331		 * data.
 332		 *
 333		 * However, the DSCR and CTRLA registers cannot be read both
 334		 * atomically. Hence a race condition may occur: the first read
 335		 * register may refer to one child descriptor whereas the second
 336		 * read may refer to a later child descriptor in the list
 337		 * because of the DMA transfer progression inbetween the two
 338		 * reads.
 339		 *
 340		 * One solution could have been to pause the DMA transfer, read
 341		 * the DSCR and CTRLA then resume the DMA transfer. Nonetheless,
 342		 * this approach presents some drawbacks:
 343		 * - If the DMA transfer is paused, RX overruns or TX underruns
 344		 *   are more likey to occur depending on the system latency.
 345		 *   Taking the USART driver as an example, it uses a cyclic DMA
 346		 *   transfer to read data from the Receive Holding Register
 347		 *   (RHR) to avoid RX overruns since the RHR is not protected
 348		 *   by any FIFO on most Atmel SoCs. So pausing the DMA transfer
 349		 *   to compute the residue would break the USART driver design.
 350		 * - The atc_pause() function masks interrupts but we'd rather
 351		 *   avoid to do so for system latency purpose.
 352		 *
 353		 * Then we'd rather use another solution: the DSCR is read a
 354		 * first time, the CTRLA is read in turn, next the DSCR is read
 355		 * a second time. If the two consecutive read values of the DSCR
 356		 * are the same then we assume both refers to the very same
 357		 * child descriptor as well as the CTRLA value read inbetween
 358		 * does. For cyclic tranfers, the assumption is that a full loop
 359		 * is "not so fast".
 360		 * If the two DSCR values are different, we read again the CTRLA
 361		 * then the DSCR till two consecutive read values from DSCR are
 362		 * equal or till the maxium trials is reach.
 363		 * This algorithm is very unlikely not to find a stable value for
 364		 * DSCR.
 365		 */
 366
 367		dscr = channel_readl(atchan, DSCR);
 368		rmb(); /* ensure DSCR is read before CTRLA */
 369		ctrla = channel_readl(atchan, CTRLA);
 370		for (trials = 0; trials < ATC_MAX_DSCR_TRIALS; ++trials) {
 371			u32 new_dscr;
 372
 373			rmb(); /* ensure DSCR is read after CTRLA */
 374			new_dscr = channel_readl(atchan, DSCR);
 375
 376			/*
 377			 * If the DSCR register value has not changed inside the
 378			 * DMA controller since the previous read, we assume
 379			 * that both the dscr and ctrla values refers to the
 380			 * very same descriptor.
 381			 */
 382			if (likely(new_dscr == dscr))
 383				break;
 384
 385			/*
 386			 * DSCR has changed inside the DMA controller, so the
 387			 * previouly read value of CTRLA may refer to an already
 388			 * processed descriptor hence could be outdated.
 389			 * We need to update ctrla to match the current
 390			 * descriptor.
 391			 */
 392			dscr = new_dscr;
 393			rmb(); /* ensure DSCR is read before CTRLA */
 394			ctrla = channel_readl(atchan, CTRLA);
 395		}
 396		if (unlikely(trials >= ATC_MAX_DSCR_TRIALS))
 397			return -ETIMEDOUT;
 398
 399		/* for the first descriptor we can be more accurate */
 400		if (desc_first->lli.dscr == dscr)
 401			return atc_calc_bytes_left(ret, ctrla);
 402
 403		ret -= desc_first->len;
 404		list_for_each_entry(desc, &desc_first->tx_list, desc_node) {
 405			if (desc->lli.dscr == dscr)
 406				break;
 407
 408			ret -= desc->len;
 409		}
 410
 411		/*
 412		 * For the current descriptor in the chain we can calculate
 413		 * the remaining bytes using the channel's register.
 414		 */
 415		ret = atc_calc_bytes_left(ret, ctrla);
 416	} else {
 417		/* single transfer */
 418		ctrla = channel_readl(atchan, CTRLA);
 419		ret = atc_calc_bytes_left(ret, ctrla);
 420	}
 421
 422	return ret;
 423}
 424
 425/**
 426 * atc_chain_complete - finish work for one transaction chain
 427 * @atchan: channel we work on
 428 * @desc: descriptor at the head of the chain we want do complete
 429 */
 
 430static void
 431atc_chain_complete(struct at_dma_chan *atchan, struct at_desc *desc)
 432{
 433	struct dma_async_tx_descriptor	*txd = &desc->txd;
 434	struct at_dma			*atdma = to_at_dma(atchan->chan_common.device);
 435	unsigned long flags;
 436
 437	dev_vdbg(chan2dev(&atchan->chan_common),
 438		"descriptor %u complete\n", txd->cookie);
 439
 440	spin_lock_irqsave(&atchan->lock, flags);
 441
 442	/* mark the descriptor as complete for non cyclic cases only */
 443	if (!atc_chan_is_cyclic(atchan))
 444		dma_cookie_complete(txd);
 445
 446	/* If the transfer was a memset, free our temporary buffer */
 447	if (desc->memset_buffer) {
 448		dma_pool_free(atdma->memset_pool, desc->memset_vaddr,
 449			      desc->memset_paddr);
 450		desc->memset_buffer = false;
 451	}
 452
 453	/* move children to free_list */
 454	list_splice_init(&desc->tx_list, &atchan->free_list);
 455	/* move myself to free_list */
 456	list_move(&desc->desc_node, &atchan->free_list);
 457
 458	spin_unlock_irqrestore(&atchan->lock, flags);
 459
 460	dma_descriptor_unmap(txd);
 461	/* for cyclic transfers,
 462	 * no need to replay callback function while stopping */
 463	if (!atc_chan_is_cyclic(atchan))
 
 
 
 
 464		dmaengine_desc_get_callback_invoke(txd, NULL);
 
 465
 466	dma_run_dependencies(txd);
 467}
 468
 469/**
 470 * atc_complete_all - finish work for all transactions
 471 * @atchan: channel to complete transactions for
 472 *
 473 * Eventually submit queued descriptors if any
 474 *
 475 * Assume channel is idle while calling this function
 476 * Called with atchan->lock held and bh disabled
 477 */
 478static void atc_complete_all(struct at_dma_chan *atchan)
 479{
 480	struct at_desc *desc, *_desc;
 481	LIST_HEAD(list);
 482	unsigned long flags;
 483
 484	dev_vdbg(chan2dev(&atchan->chan_common), "complete all\n");
 485
 486	spin_lock_irqsave(&atchan->lock, flags);
 487
 488	/*
 489	 * Submit queued descriptors ASAP, i.e. before we go through
 490	 * the completed ones.
 491	 */
 492	if (!list_empty(&atchan->queue))
 493		atc_dostart(atchan, atc_first_queued(atchan));
 494	/* empty active_list now it is completed */
 495	list_splice_init(&atchan->active_list, &list);
 496	/* empty queue list by moving descriptors (if any) to active_list */
 497	list_splice_init(&atchan->queue, &atchan->active_list);
 498
 499	spin_unlock_irqrestore(&atchan->lock, flags);
 500
 501	list_for_each_entry_safe(desc, _desc, &list, desc_node)
 502		atc_chain_complete(atchan, desc);
 503}
 504
 505/**
 506 * atc_advance_work - at the end of a transaction, move forward
 507 * @atchan: channel where the transaction ended
 
 
 508 */
 509static void atc_advance_work(struct at_dma_chan *atchan)
 510{
 511	unsigned long flags;
 512	int ret;
 513
 514	dev_vdbg(chan2dev(&atchan->chan_common), "advance_work\n");
 515
 516	spin_lock_irqsave(&atchan->lock, flags);
 517	ret = atc_chan_is_enabled(atchan);
 518	spin_unlock_irqrestore(&atchan->lock, flags);
 519	if (ret)
 520		return;
 521
 522	if (list_empty(&atchan->active_list) ||
 523	    list_is_singular(&atchan->active_list))
 524		return atc_complete_all(atchan);
 525
 526	atc_chain_complete(atchan, atc_first_active(atchan));
 527
 528	/* advance work */
 529	spin_lock_irqsave(&atchan->lock, flags);
 530	atc_dostart(atchan, atc_first_active(atchan));
 531	spin_unlock_irqrestore(&atchan->lock, flags);
 532}
 533
 534
 535/**
 536 * atc_handle_error - handle errors reported by DMA controller
 537 * @atchan: channel where error occurs
 
 
 538 */
 539static void atc_handle_error(struct at_dma_chan *atchan)
 540{
 541	struct at_desc *bad_desc;
 542	struct at_desc *child;
 543	unsigned long flags;
 544
 545	spin_lock_irqsave(&atchan->lock, flags);
 546	/*
 547	 * The descriptor currently at the head of the active list is
 548	 * broked. Since we don't have any way to report errors, we'll
 549	 * just have to scream loudly and try to carry on.
 550	 */
 551	bad_desc = atc_first_active(atchan);
 552	list_del_init(&bad_desc->desc_node);
 553
 554	/* As we are stopped, take advantage to push queued descriptors
 555	 * in active_list */
 556	list_splice_init(&atchan->queue, atchan->active_list.prev);
 557
 558	/* Try to restart the controller */
 559	if (!list_empty(&atchan->active_list))
 560		atc_dostart(atchan, atc_first_active(atchan));
 561
 562	/*
 563	 * KERN_CRITICAL may seem harsh, but since this only happens
 564	 * when someone submits a bad physical address in a
 565	 * descriptor, we should consider ourselves lucky that the
 566	 * controller flagged an error instead of scribbling over
 567	 * random memory locations.
 568	 */
 569	dev_crit(chan2dev(&atchan->chan_common),
 570			"Bad descriptor submitted for DMA!\n");
 571	dev_crit(chan2dev(&atchan->chan_common),
 572			"  cookie: %d\n", bad_desc->txd.cookie);
 573	atc_dump_lli(atchan, &bad_desc->lli);
 574	list_for_each_entry(child, &bad_desc->tx_list, desc_node)
 575		atc_dump_lli(atchan, &child->lli);
 576
 577	spin_unlock_irqrestore(&atchan->lock, flags);
 578
 579	/* Pretend the descriptor completed successfully */
 580	atc_chain_complete(atchan, bad_desc);
 581}
 582
 583/**
 584 * atc_handle_cyclic - at the end of a period, run callback function
 585 * @atchan: channel used for cyclic operations
 
 
 586 */
 587static void atc_handle_cyclic(struct at_dma_chan *atchan)
 588{
 589	struct at_desc			*first = atc_first_active(atchan);
 590	struct dma_async_tx_descriptor	*txd = &first->txd;
 591
 592	dev_vdbg(chan2dev(&atchan->chan_common),
 593			"new cyclic period llp 0x%08x\n",
 594			channel_readl(atchan, DSCR));
 595
 596	dmaengine_desc_get_callback_invoke(txd, NULL);
 597}
 598
 599/*--  IRQ & Tasklet  ---------------------------------------------------*/
 600
 601static void atc_tasklet(unsigned long data)
 602{
 603	struct at_dma_chan *atchan = (struct at_dma_chan *)data;
 
 604
 
 605	if (test_and_clear_bit(ATC_IS_ERROR, &atchan->status))
 606		return atc_handle_error(atchan);
 607
 608	if (atc_chan_is_cyclic(atchan))
 609		return atc_handle_cyclic(atchan);
 
 610
 611	atc_advance_work(atchan);
 612}
 613
 614static irqreturn_t at_dma_interrupt(int irq, void *dev_id)
 615{
 616	struct at_dma		*atdma = (struct at_dma *)dev_id;
 617	struct at_dma_chan	*atchan;
 618	int			i;
 619	u32			status, pending, imr;
 620	int			ret = IRQ_NONE;
 621
 622	do {
 623		imr = dma_readl(atdma, EBCIMR);
 624		status = dma_readl(atdma, EBCISR);
 625		pending = status & imr;
 626
 627		if (!pending)
 628			break;
 629
 630		dev_vdbg(atdma->dma_common.dev,
 631			"interrupt: status = 0x%08x, 0x%08x, 0x%08x\n",
 632			 status, imr, pending);
 633
 634		for (i = 0; i < atdma->dma_common.chancnt; i++) {
 635			atchan = &atdma->chan[i];
 636			if (pending & (AT_DMA_BTC(i) | AT_DMA_ERR(i))) {
 637				if (pending & AT_DMA_ERR(i)) {
 638					/* Disable channel on AHB error */
 639					dma_writel(atdma, CHDR,
 640						AT_DMA_RES(i) | atchan->mask);
 641					/* Give information to tasklet */
 642					set_bit(ATC_IS_ERROR, &atchan->status);
 643				}
 644				tasklet_schedule(&atchan->tasklet);
 645				ret = IRQ_HANDLED;
 646			}
 647		}
 648
 649	} while (pending);
 650
 651	return ret;
 652}
 653
 654
 655/*--  DMA Engine API  --------------------------------------------------*/
 656
 657/**
 658 * atc_tx_submit - set the prepared descriptor(s) to be executed by the engine
 659 * @tx: descriptor at the head of the transaction chain
 660 *
 661 * Queue chain if DMA engine is working already
 662 *
 663 * Cookie increment and adding to active_list or queue must be atomic
 664 */
 665static dma_cookie_t atc_tx_submit(struct dma_async_tx_descriptor *tx)
 666{
 667	struct at_desc		*desc = txd_to_at_desc(tx);
 668	struct at_dma_chan	*atchan = to_at_dma_chan(tx->chan);
 669	dma_cookie_t		cookie;
 670	unsigned long		flags;
 671
 672	spin_lock_irqsave(&atchan->lock, flags);
 673	cookie = dma_cookie_assign(tx);
 674
 675	if (list_empty(&atchan->active_list)) {
 676		dev_vdbg(chan2dev(tx->chan), "tx_submit: started %u\n",
 677				desc->txd.cookie);
 678		atc_dostart(atchan, desc);
 679		list_add_tail(&desc->desc_node, &atchan->active_list);
 680	} else {
 681		dev_vdbg(chan2dev(tx->chan), "tx_submit: queued %u\n",
 682				desc->txd.cookie);
 683		list_add_tail(&desc->desc_node, &atchan->queue);
 684	}
 685
 686	spin_unlock_irqrestore(&atchan->lock, flags);
 687
 688	return cookie;
 689}
 690
 691/**
 692 * atc_prep_dma_interleaved - prepare memory to memory interleaved operation
 693 * @chan: the channel to prepare operation on
 694 * @xt: Interleaved transfer template
 695 * @flags: tx descriptor status flags
 696 */
 697static struct dma_async_tx_descriptor *
 698atc_prep_dma_interleaved(struct dma_chan *chan,
 699			 struct dma_interleaved_template *xt,
 700			 unsigned long flags)
 701{
 702	struct at_dma_chan	*atchan = to_at_dma_chan(chan);
 703	struct data_chunk	*first;
 704	struct at_desc		*desc = NULL;
 705	size_t			xfer_count;
 706	unsigned int		dwidth;
 707	u32			ctrla;
 708	u32			ctrlb;
 709	size_t			len = 0;
 710	int			i;
 711
 712	if (unlikely(!xt || xt->numf != 1 || !xt->frame_size))
 713		return NULL;
 714
 715	first = xt->sgl;
 716
 717	dev_info(chan2dev(chan),
 718		 "%s: src=%pad, dest=%pad, numf=%d, frame_size=%d, flags=0x%lx\n",
 719		__func__, &xt->src_start, &xt->dst_start, xt->numf,
 720		xt->frame_size, flags);
 721
 722	/*
 723	 * The controller can only "skip" X bytes every Y bytes, so we
 724	 * need to make sure we are given a template that fit that
 725	 * description, ie a template with chunks that always have the
 726	 * same size, with the same ICGs.
 727	 */
 728	for (i = 0; i < xt->frame_size; i++) {
 729		struct data_chunk *chunk = xt->sgl + i;
 730
 731		if ((chunk->size != xt->sgl->size) ||
 732		    (dmaengine_get_dst_icg(xt, chunk) != dmaengine_get_dst_icg(xt, first)) ||
 733		    (dmaengine_get_src_icg(xt, chunk) != dmaengine_get_src_icg(xt, first))) {
 734			dev_err(chan2dev(chan),
 735				"%s: the controller can transfer only identical chunks\n",
 736				__func__);
 737			return NULL;
 738		}
 739
 740		len += chunk->size;
 741	}
 742
 743	dwidth = atc_get_xfer_width(xt->src_start,
 744				    xt->dst_start, len);
 745
 746	xfer_count = len >> dwidth;
 747	if (xfer_count > ATC_BTSIZE_MAX) {
 748		dev_err(chan2dev(chan), "%s: buffer is too big\n", __func__);
 749		return NULL;
 750	}
 751
 752	ctrla = ATC_SRC_WIDTH(dwidth) |
 753		ATC_DST_WIDTH(dwidth);
 754
 755	ctrlb =   ATC_DEFAULT_CTRLB | ATC_IEN
 756		| ATC_SRC_ADDR_MODE_INCR
 757		| ATC_DST_ADDR_MODE_INCR
 758		| ATC_SRC_PIP
 759		| ATC_DST_PIP
 760		| ATC_FC_MEM2MEM;
 761
 762	/* create the transfer */
 763	desc = atc_desc_get(atchan);
 764	if (!desc) {
 765		dev_err(chan2dev(chan),
 766			"%s: couldn't allocate our descriptor\n", __func__);
 767		return NULL;
 768	}
 769
 770	desc->lli.saddr = xt->src_start;
 771	desc->lli.daddr = xt->dst_start;
 772	desc->lli.ctrla = ctrla | xfer_count;
 773	desc->lli.ctrlb = ctrlb;
 774
 775	desc->boundary = first->size >> dwidth;
 776	desc->dst_hole = (dmaengine_get_dst_icg(xt, first) >> dwidth) + 1;
 777	desc->src_hole = (dmaengine_get_src_icg(xt, first) >> dwidth) + 1;
 778
 779	desc->txd.cookie = -EBUSY;
 780	desc->total_len = desc->len = len;
 781
 782	/* set end-of-link to the last link descriptor of list*/
 783	set_desc_eol(desc);
 784
 785	desc->txd.flags = flags; /* client is in control of this ack */
 786
 787	return &desc->txd;
 788}
 789
 790/**
 791 * atc_prep_dma_memcpy - prepare a memcpy operation
 792 * @chan: the channel to prepare operation on
 793 * @dest: operation virtual destination address
 794 * @src: operation virtual source address
 795 * @len: operation length
 796 * @flags: tx descriptor status flags
 797 */
 798static struct dma_async_tx_descriptor *
 799atc_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dest, dma_addr_t src,
 800		size_t len, unsigned long flags)
 801{
 802	struct at_dma_chan	*atchan = to_at_dma_chan(chan);
 803	struct at_desc		*desc = NULL;
 804	struct at_desc		*first = NULL;
 805	struct at_desc		*prev = NULL;
 806	size_t			xfer_count;
 807	size_t			offset;
 808	unsigned int		src_width;
 809	unsigned int		dst_width;
 810	u32			ctrla;
 811	u32			ctrlb;
 812
 813	dev_vdbg(chan2dev(chan), "prep_dma_memcpy: d%pad s%pad l0x%zx f0x%lx\n",
 814			&dest, &src, len, flags);
 815
 816	if (unlikely(!len)) {
 817		dev_dbg(chan2dev(chan), "prep_dma_memcpy: length is zero!\n");
 818		return NULL;
 819	}
 820
 821	ctrlb =   ATC_DEFAULT_CTRLB | ATC_IEN
 822		| ATC_SRC_ADDR_MODE_INCR
 823		| ATC_DST_ADDR_MODE_INCR
 824		| ATC_FC_MEM2MEM;
 825
 826	/*
 827	 * We can be a lot more clever here, but this should take care
 828	 * of the most common optimization.
 829	 */
 830	src_width = dst_width = atc_get_xfer_width(src, dest, len);
 831
 832	ctrla = ATC_SRC_WIDTH(src_width) |
 833		ATC_DST_WIDTH(dst_width);
 834
 835	for (offset = 0; offset < len; offset += xfer_count << src_width) {
 836		xfer_count = min_t(size_t, (len - offset) >> src_width,
 837				ATC_BTSIZE_MAX);
 838
 839		desc = atc_desc_get(atchan);
 840		if (!desc)
 841			goto err_desc_get;
 842
 843		desc->lli.saddr = src + offset;
 844		desc->lli.daddr = dest + offset;
 845		desc->lli.ctrla = ctrla | xfer_count;
 846		desc->lli.ctrlb = ctrlb;
 847
 848		desc->txd.cookie = 0;
 849		desc->len = xfer_count << src_width;
 850
 851		atc_desc_chain(&first, &prev, desc);
 852	}
 853
 854	/* First descriptor of the chain embedds additional information */
 855	first->txd.cookie = -EBUSY;
 856	first->total_len = len;
 857
 858	/* set end-of-link to the last link descriptor of list*/
 859	set_desc_eol(desc);
 860
 861	first->txd.flags = flags; /* client is in control of this ack */
 862
 863	return &first->txd;
 864
 865err_desc_get:
 866	atc_desc_put(atchan, first);
 867	return NULL;
 868}
 869
 870static struct at_desc *atc_create_memset_desc(struct dma_chan *chan,
 871					      dma_addr_t psrc,
 872					      dma_addr_t pdst,
 873					      size_t len)
 874{
 875	struct at_dma_chan *atchan = to_at_dma_chan(chan);
 876	struct at_desc *desc;
 877	size_t xfer_count;
 878
 879	u32 ctrla = ATC_SRC_WIDTH(2) | ATC_DST_WIDTH(2);
 880	u32 ctrlb = ATC_DEFAULT_CTRLB | ATC_IEN |
 881		ATC_SRC_ADDR_MODE_FIXED |
 882		ATC_DST_ADDR_MODE_INCR |
 883		ATC_FC_MEM2MEM;
 884
 885	xfer_count = len >> 2;
 886	if (xfer_count > ATC_BTSIZE_MAX) {
 887		dev_err(chan2dev(chan), "%s: buffer is too big\n",
 888			__func__);
 889		return NULL;
 890	}
 891
 892	desc = atc_desc_get(atchan);
 893	if (!desc) {
 894		dev_err(chan2dev(chan), "%s: can't get a descriptor\n",
 895			__func__);
 896		return NULL;
 897	}
 898
 899	desc->lli.saddr = psrc;
 900	desc->lli.daddr = pdst;
 901	desc->lli.ctrla = ctrla | xfer_count;
 902	desc->lli.ctrlb = ctrlb;
 903
 904	desc->txd.cookie = 0;
 905	desc->len = len;
 906
 907	return desc;
 908}
 909
 910/**
 911 * atc_prep_dma_memset - prepare a memcpy operation
 912 * @chan: the channel to prepare operation on
 913 * @dest: operation virtual destination address
 914 * @value: value to set memory buffer to
 915 * @len: operation length
 916 * @flags: tx descriptor status flags
 917 */
 918static struct dma_async_tx_descriptor *
 919atc_prep_dma_memset(struct dma_chan *chan, dma_addr_t dest, int value,
 920		    size_t len, unsigned long flags)
 921{
 922	struct at_dma		*atdma = to_at_dma(chan->device);
 923	struct at_desc		*desc;
 924	void __iomem		*vaddr;
 925	dma_addr_t		paddr;
 926
 927	dev_vdbg(chan2dev(chan), "%s: d%pad v0x%x l0x%zx f0x%lx\n", __func__,
 928		&dest, value, len, flags);
 929
 930	if (unlikely(!len)) {
 931		dev_dbg(chan2dev(chan), "%s: length is zero!\n", __func__);
 932		return NULL;
 933	}
 934
 935	if (!is_dma_fill_aligned(chan->device, dest, 0, len)) {
 936		dev_dbg(chan2dev(chan), "%s: buffer is not aligned\n",
 937			__func__);
 938		return NULL;
 939	}
 940
 941	vaddr = dma_pool_alloc(atdma->memset_pool, GFP_NOWAIT, &paddr);
 942	if (!vaddr) {
 943		dev_err(chan2dev(chan), "%s: couldn't allocate buffer\n",
 944			__func__);
 945		return NULL;
 946	}
 947	*(u32*)vaddr = value;
 948
 949	desc = atc_create_memset_desc(chan, paddr, dest, len);
 950	if (!desc) {
 951		dev_err(chan2dev(chan), "%s: couldn't get a descriptor\n",
 952			__func__);
 953		goto err_free_buffer;
 954	}
 955
 956	desc->memset_paddr = paddr;
 957	desc->memset_vaddr = vaddr;
 958	desc->memset_buffer = true;
 959
 960	desc->txd.cookie = -EBUSY;
 961	desc->total_len = len;
 962
 963	/* set end-of-link on the descriptor */
 964	set_desc_eol(desc);
 965
 966	desc->txd.flags = flags;
 967
 968	return &desc->txd;
 969
 970err_free_buffer:
 971	dma_pool_free(atdma->memset_pool, vaddr, paddr);
 972	return NULL;
 973}
 974
 975static struct dma_async_tx_descriptor *
 976atc_prep_dma_memset_sg(struct dma_chan *chan,
 977		       struct scatterlist *sgl,
 978		       unsigned int sg_len, int value,
 979		       unsigned long flags)
 980{
 981	struct at_dma_chan	*atchan = to_at_dma_chan(chan);
 982	struct at_dma		*atdma = to_at_dma(chan->device);
 983	struct at_desc		*desc = NULL, *first = NULL, *prev = NULL;
 984	struct scatterlist	*sg;
 985	void __iomem		*vaddr;
 986	dma_addr_t		paddr;
 987	size_t			total_len = 0;
 988	int			i;
 989
 990	dev_vdbg(chan2dev(chan), "%s: v0x%x l0x%zx f0x%lx\n", __func__,
 991		 value, sg_len, flags);
 992
 993	if (unlikely(!sgl || !sg_len)) {
 994		dev_dbg(chan2dev(chan), "%s: scatterlist is empty!\n",
 995			__func__);
 996		return NULL;
 997	}
 998
 999	vaddr = dma_pool_alloc(atdma->memset_pool, GFP_NOWAIT, &paddr);
1000	if (!vaddr) {
1001		dev_err(chan2dev(chan), "%s: couldn't allocate buffer\n",
1002			__func__);
1003		return NULL;
1004	}
1005	*(u32*)vaddr = value;
1006
1007	for_each_sg(sgl, sg, sg_len, i) {
1008		dma_addr_t dest = sg_dma_address(sg);
1009		size_t len = sg_dma_len(sg);
1010
1011		dev_vdbg(chan2dev(chan), "%s: d%pad, l0x%zx\n",
1012			 __func__, &dest, len);
1013
1014		if (!is_dma_fill_aligned(chan->device, dest, 0, len)) {
1015			dev_err(chan2dev(chan), "%s: buffer is not aligned\n",
1016				__func__);
1017			goto err_put_desc;
1018		}
1019
1020		desc = atc_create_memset_desc(chan, paddr, dest, len);
1021		if (!desc)
1022			goto err_put_desc;
1023
1024		atc_desc_chain(&first, &prev, desc);
1025
1026		total_len += len;
1027	}
1028
1029	/*
1030	 * Only set the buffer pointers on the last descriptor to
1031	 * avoid free'ing while we have our transfer still going
1032	 */
1033	desc->memset_paddr = paddr;
1034	desc->memset_vaddr = vaddr;
1035	desc->memset_buffer = true;
1036
1037	first->txd.cookie = -EBUSY;
1038	first->total_len = total_len;
1039
1040	/* set end-of-link on the descriptor */
1041	set_desc_eol(desc);
1042
1043	first->txd.flags = flags;
1044
1045	return &first->txd;
1046
1047err_put_desc:
1048	atc_desc_put(atchan, first);
1049	return NULL;
1050}
1051
1052/**
1053 * atc_prep_slave_sg - prepare descriptors for a DMA_SLAVE transaction
1054 * @chan: DMA channel
1055 * @sgl: scatterlist to transfer to/from
1056 * @sg_len: number of entries in @scatterlist
1057 * @direction: DMA direction
1058 * @flags: tx descriptor status flags
1059 * @context: transaction context (ignored)
1060 */
1061static struct dma_async_tx_descriptor *
1062atc_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
1063		unsigned int sg_len, enum dma_transfer_direction direction,
1064		unsigned long flags, void *context)
1065{
1066	struct at_dma_chan	*atchan = to_at_dma_chan(chan);
1067	struct at_dma_slave	*atslave = chan->private;
1068	struct dma_slave_config	*sconfig = &atchan->dma_sconfig;
1069	struct at_desc		*first = NULL;
1070	struct at_desc		*prev = NULL;
1071	u32			ctrla;
1072	u32			ctrlb;
1073	dma_addr_t		reg;
1074	unsigned int		reg_width;
1075	unsigned int		mem_width;
1076	unsigned int		i;
1077	struct scatterlist	*sg;
1078	size_t			total_len = 0;
1079
1080	dev_vdbg(chan2dev(chan), "prep_slave_sg (%d): %s f0x%lx\n",
1081			sg_len,
1082			direction == DMA_MEM_TO_DEV ? "TO DEVICE" : "FROM DEVICE",
1083			flags);
1084
1085	if (unlikely(!atslave || !sg_len)) {
1086		dev_dbg(chan2dev(chan), "prep_slave_sg: sg length is zero!\n");
1087		return NULL;
1088	}
1089
1090	ctrla =   ATC_SCSIZE(sconfig->src_maxburst)
1091		| ATC_DCSIZE(sconfig->dst_maxburst);
1092	ctrlb = ATC_IEN;
1093
1094	switch (direction) {
1095	case DMA_MEM_TO_DEV:
1096		reg_width = convert_buswidth(sconfig->dst_addr_width);
1097		ctrla |=  ATC_DST_WIDTH(reg_width);
1098		ctrlb |=  ATC_DST_ADDR_MODE_FIXED
1099			| ATC_SRC_ADDR_MODE_INCR
1100			| ATC_FC_MEM2PER
1101			| ATC_SIF(atchan->mem_if) | ATC_DIF(atchan->per_if);
1102		reg = sconfig->dst_addr;
1103		for_each_sg(sgl, sg, sg_len, i) {
1104			struct at_desc	*desc;
1105			u32		len;
1106			u32		mem;
1107
1108			desc = atc_desc_get(atchan);
1109			if (!desc)
1110				goto err_desc_get;
1111
1112			mem = sg_dma_address(sg);
1113			len = sg_dma_len(sg);
1114			if (unlikely(!len)) {
1115				dev_dbg(chan2dev(chan),
1116					"prep_slave_sg: sg(%d) data length is zero\n", i);
1117				goto err;
1118			}
1119			mem_width = 2;
1120			if (unlikely(mem & 3 || len & 3))
1121				mem_width = 0;
1122
1123			desc->lli.saddr = mem;
1124			desc->lli.daddr = reg;
1125			desc->lli.ctrla = ctrla
1126					| ATC_SRC_WIDTH(mem_width)
1127					| len >> mem_width;
1128			desc->lli.ctrlb = ctrlb;
1129			desc->len = len;
1130
1131			atc_desc_chain(&first, &prev, desc);
1132			total_len += len;
1133		}
1134		break;
1135	case DMA_DEV_TO_MEM:
1136		reg_width = convert_buswidth(sconfig->src_addr_width);
1137		ctrla |=  ATC_SRC_WIDTH(reg_width);
1138		ctrlb |=  ATC_DST_ADDR_MODE_INCR
1139			| ATC_SRC_ADDR_MODE_FIXED
1140			| ATC_FC_PER2MEM
1141			| ATC_SIF(atchan->per_if) | ATC_DIF(atchan->mem_if);
1142
1143		reg = sconfig->src_addr;
1144		for_each_sg(sgl, sg, sg_len, i) {
1145			struct at_desc	*desc;
1146			u32		len;
1147			u32		mem;
1148
1149			desc = atc_desc_get(atchan);
1150			if (!desc)
1151				goto err_desc_get;
1152
1153			mem = sg_dma_address(sg);
1154			len = sg_dma_len(sg);
1155			if (unlikely(!len)) {
1156				dev_dbg(chan2dev(chan),
1157					"prep_slave_sg: sg(%d) data length is zero\n", i);
1158				goto err;
1159			}
1160			mem_width = 2;
1161			if (unlikely(mem & 3 || len & 3))
1162				mem_width = 0;
1163
1164			desc->lli.saddr = reg;
1165			desc->lli.daddr = mem;
1166			desc->lli.ctrla = ctrla
1167					| ATC_DST_WIDTH(mem_width)
1168					| len >> reg_width;
1169			desc->lli.ctrlb = ctrlb;
1170			desc->len = len;
1171
1172			atc_desc_chain(&first, &prev, desc);
1173			total_len += len;
1174		}
1175		break;
1176	default:
1177		return NULL;
1178	}
1179
1180	/* set end-of-link to the last link descriptor of list*/
1181	set_desc_eol(prev);
1182
1183	/* First descriptor of the chain embedds additional information */
1184	first->txd.cookie = -EBUSY;
1185	first->total_len = total_len;
1186
1187	/* first link descriptor of list is responsible of flags */
1188	first->txd.flags = flags; /* client is in control of this ack */
1189
1190	return &first->txd;
1191
1192err_desc_get:
1193	dev_err(chan2dev(chan), "not enough descriptors available\n");
1194err:
1195	atc_desc_put(atchan, first);
1196	return NULL;
1197}
1198
1199/*
1200 * atc_dma_cyclic_check_values
1201 * Check for too big/unaligned periods and unaligned DMA buffer
1202 */
1203static int
1204atc_dma_cyclic_check_values(unsigned int reg_width, dma_addr_t buf_addr,
1205		size_t period_len)
1206{
1207	if (period_len > (ATC_BTSIZE_MAX << reg_width))
1208		goto err_out;
1209	if (unlikely(period_len & ((1 << reg_width) - 1)))
1210		goto err_out;
1211	if (unlikely(buf_addr & ((1 << reg_width) - 1)))
1212		goto err_out;
1213
1214	return 0;
1215
1216err_out:
1217	return -EINVAL;
1218}
1219
1220/*
1221 * atc_dma_cyclic_fill_desc - Fill one period descriptor
1222 */
1223static int
1224atc_dma_cyclic_fill_desc(struct dma_chan *chan, struct at_desc *desc,
1225		unsigned int period_index, dma_addr_t buf_addr,
1226		unsigned int reg_width, size_t period_len,
1227		enum dma_transfer_direction direction)
1228{
1229	struct at_dma_chan	*atchan = to_at_dma_chan(chan);
1230	struct dma_slave_config	*sconfig = &atchan->dma_sconfig;
1231	u32			ctrla;
1232
1233	/* prepare common CRTLA value */
1234	ctrla =   ATC_SCSIZE(sconfig->src_maxburst)
1235		| ATC_DCSIZE(sconfig->dst_maxburst)
1236		| ATC_DST_WIDTH(reg_width)
1237		| ATC_SRC_WIDTH(reg_width)
1238		| period_len >> reg_width;
1239
1240	switch (direction) {
1241	case DMA_MEM_TO_DEV:
1242		desc->lli.saddr = buf_addr + (period_len * period_index);
1243		desc->lli.daddr = sconfig->dst_addr;
1244		desc->lli.ctrla = ctrla;
1245		desc->lli.ctrlb = ATC_DST_ADDR_MODE_FIXED
1246				| ATC_SRC_ADDR_MODE_INCR
1247				| ATC_FC_MEM2PER
1248				| ATC_SIF(atchan->mem_if)
1249				| ATC_DIF(atchan->per_if);
1250		desc->len = period_len;
1251		break;
1252
1253	case DMA_DEV_TO_MEM:
1254		desc->lli.saddr = sconfig->src_addr;
1255		desc->lli.daddr = buf_addr + (period_len * period_index);
1256		desc->lli.ctrla = ctrla;
1257		desc->lli.ctrlb = ATC_DST_ADDR_MODE_INCR
1258				| ATC_SRC_ADDR_MODE_FIXED
1259				| ATC_FC_PER2MEM
1260				| ATC_SIF(atchan->per_if)
1261				| ATC_DIF(atchan->mem_if);
1262		desc->len = period_len;
1263		break;
1264
1265	default:
1266		return -EINVAL;
1267	}
1268
1269	return 0;
1270}
1271
1272/**
1273 * atc_prep_dma_cyclic - prepare the cyclic DMA transfer
1274 * @chan: the DMA channel to prepare
1275 * @buf_addr: physical DMA address where the buffer starts
1276 * @buf_len: total number of bytes for the entire buffer
1277 * @period_len: number of bytes for each period
1278 * @direction: transfer direction, to or from device
1279 * @flags: tx descriptor status flags
1280 */
1281static struct dma_async_tx_descriptor *
1282atc_prep_dma_cyclic(struct dma_chan *chan, dma_addr_t buf_addr, size_t buf_len,
1283		size_t period_len, enum dma_transfer_direction direction,
1284		unsigned long flags)
1285{
1286	struct at_dma_chan	*atchan = to_at_dma_chan(chan);
1287	struct at_dma_slave	*atslave = chan->private;
1288	struct dma_slave_config	*sconfig = &atchan->dma_sconfig;
1289	struct at_desc		*first = NULL;
1290	struct at_desc		*prev = NULL;
1291	unsigned long		was_cyclic;
1292	unsigned int		reg_width;
1293	unsigned int		periods = buf_len / period_len;
1294	unsigned int		i;
1295
1296	dev_vdbg(chan2dev(chan), "prep_dma_cyclic: %s buf@%pad - %d (%d/%d)\n",
1297			direction == DMA_MEM_TO_DEV ? "TO DEVICE" : "FROM DEVICE",
1298			&buf_addr,
1299			periods, buf_len, period_len);
1300
1301	if (unlikely(!atslave || !buf_len || !period_len)) {
1302		dev_dbg(chan2dev(chan), "prep_dma_cyclic: length is zero!\n");
1303		return NULL;
1304	}
1305
1306	was_cyclic = test_and_set_bit(ATC_IS_CYCLIC, &atchan->status);
1307	if (was_cyclic) {
1308		dev_dbg(chan2dev(chan), "prep_dma_cyclic: channel in use!\n");
1309		return NULL;
1310	}
1311
1312	if (unlikely(!is_slave_direction(direction)))
1313		goto err_out;
1314
1315	if (direction == DMA_MEM_TO_DEV)
1316		reg_width = convert_buswidth(sconfig->dst_addr_width);
1317	else
1318		reg_width = convert_buswidth(sconfig->src_addr_width);
1319
1320	/* Check for too big/unaligned periods and unaligned DMA buffer */
1321	if (atc_dma_cyclic_check_values(reg_width, buf_addr, period_len))
1322		goto err_out;
1323
1324	/* build cyclic linked list */
1325	for (i = 0; i < periods; i++) {
1326		struct at_desc	*desc;
1327
1328		desc = atc_desc_get(atchan);
1329		if (!desc)
1330			goto err_desc_get;
1331
1332		if (atc_dma_cyclic_fill_desc(chan, desc, i, buf_addr,
1333					     reg_width, period_len, direction))
1334			goto err_desc_get;
1335
1336		atc_desc_chain(&first, &prev, desc);
1337	}
1338
1339	/* lets make a cyclic list */
1340	prev->lli.dscr = first->txd.phys;
1341
1342	/* First descriptor of the chain embedds additional information */
1343	first->txd.cookie = -EBUSY;
1344	first->total_len = buf_len;
1345
1346	return &first->txd;
1347
1348err_desc_get:
1349	dev_err(chan2dev(chan), "not enough descriptors available\n");
1350	atc_desc_put(atchan, first);
1351err_out:
1352	clear_bit(ATC_IS_CYCLIC, &atchan->status);
1353	return NULL;
1354}
1355
1356static int atc_config(struct dma_chan *chan,
1357		      struct dma_slave_config *sconfig)
1358{
1359	struct at_dma_chan	*atchan = to_at_dma_chan(chan);
1360
1361	dev_vdbg(chan2dev(chan), "%s\n", __func__);
1362
1363	/* Check if it is chan is configured for slave transfers */
1364	if (!chan->private)
1365		return -EINVAL;
1366
1367	memcpy(&atchan->dma_sconfig, sconfig, sizeof(*sconfig));
1368
1369	convert_burst(&atchan->dma_sconfig.src_maxburst);
1370	convert_burst(&atchan->dma_sconfig.dst_maxburst);
1371
1372	return 0;
1373}
1374
1375static int atc_pause(struct dma_chan *chan)
1376{
1377	struct at_dma_chan	*atchan = to_at_dma_chan(chan);
1378	struct at_dma		*atdma = to_at_dma(chan->device);
1379	int			chan_id = atchan->chan_common.chan_id;
1380	unsigned long		flags;
1381
1382	dev_vdbg(chan2dev(chan), "%s\n", __func__);
1383
1384	spin_lock_irqsave(&atchan->lock, flags);
1385
1386	dma_writel(atdma, CHER, AT_DMA_SUSP(chan_id));
1387	set_bit(ATC_IS_PAUSED, &atchan->status);
1388
1389	spin_unlock_irqrestore(&atchan->lock, flags);
1390
1391	return 0;
1392}
1393
1394static int atc_resume(struct dma_chan *chan)
1395{
1396	struct at_dma_chan	*atchan = to_at_dma_chan(chan);
1397	struct at_dma		*atdma = to_at_dma(chan->device);
1398	int			chan_id = atchan->chan_common.chan_id;
1399	unsigned long		flags;
1400
1401	dev_vdbg(chan2dev(chan), "%s\n", __func__);
1402
1403	if (!atc_chan_is_paused(atchan))
1404		return 0;
1405
1406	spin_lock_irqsave(&atchan->lock, flags);
1407
1408	dma_writel(atdma, CHDR, AT_DMA_RES(chan_id));
1409	clear_bit(ATC_IS_PAUSED, &atchan->status);
1410
1411	spin_unlock_irqrestore(&atchan->lock, flags);
1412
1413	return 0;
1414}
1415
1416static int atc_terminate_all(struct dma_chan *chan)
1417{
1418	struct at_dma_chan	*atchan = to_at_dma_chan(chan);
1419	struct at_dma		*atdma = to_at_dma(chan->device);
1420	int			chan_id = atchan->chan_common.chan_id;
1421	struct at_desc		*desc, *_desc;
1422	unsigned long		flags;
1423
1424	LIST_HEAD(list);
1425
1426	dev_vdbg(chan2dev(chan), "%s\n", __func__);
1427
1428	/*
1429	 * This is only called when something went wrong elsewhere, so
1430	 * we don't really care about the data. Just disable the
1431	 * channel. We still have to poll the channel enable bit due
1432	 * to AHB/HSB limitations.
1433	 */
1434	spin_lock_irqsave(&atchan->lock, flags);
1435
1436	/* disabling channel: must also remove suspend state */
1437	dma_writel(atdma, CHDR, AT_DMA_RES(chan_id) | atchan->mask);
1438
1439	/* confirm that this channel is disabled */
1440	while (dma_readl(atdma, CHSR) & atchan->mask)
1441		cpu_relax();
1442
1443	/* active_list entries will end up before queued entries */
1444	list_splice_init(&atchan->queue, &list);
1445	list_splice_init(&atchan->active_list, &list);
1446
1447	spin_unlock_irqrestore(&atchan->lock, flags);
1448
1449	/* Flush all pending and queued descriptors */
1450	list_for_each_entry_safe(desc, _desc, &list, desc_node)
1451		atc_chain_complete(atchan, desc);
1452
1453	clear_bit(ATC_IS_PAUSED, &atchan->status);
1454	/* if channel dedicated to cyclic operations, free it */
1455	clear_bit(ATC_IS_CYCLIC, &atchan->status);
1456
 
 
1457	return 0;
1458}
1459
1460/**
1461 * atc_tx_status - poll for transaction completion
1462 * @chan: DMA channel
1463 * @cookie: transaction identifier to check status of
1464 * @txstate: if not %NULL updated with transaction state
1465 *
1466 * If @txstate is passed in, upon return it reflect the driver
1467 * internal state and can be used with dma_async_is_complete() to check
1468 * the status of multiple cookies without re-checking hardware state.
1469 */
1470static enum dma_status
1471atc_tx_status(struct dma_chan *chan,
1472		dma_cookie_t cookie,
1473		struct dma_tx_state *txstate)
1474{
1475	struct at_dma_chan	*atchan = to_at_dma_chan(chan);
1476	unsigned long		flags;
1477	enum dma_status		ret;
1478	int bytes = 0;
1479
1480	ret = dma_cookie_status(chan, cookie, txstate);
1481	if (ret == DMA_COMPLETE)
1482		return ret;
1483	/*
1484	 * There's no point calculating the residue if there's
1485	 * no txstate to store the value.
1486	 */
1487	if (!txstate)
1488		return DMA_ERROR;
1489
1490	spin_lock_irqsave(&atchan->lock, flags);
1491
1492	/*  Get number of bytes left in the active transactions */
1493	bytes = atc_get_bytes_left(chan, cookie);
1494
1495	spin_unlock_irqrestore(&atchan->lock, flags);
1496
1497	if (unlikely(bytes < 0)) {
1498		dev_vdbg(chan2dev(chan), "get residual bytes error\n");
1499		return DMA_ERROR;
1500	} else {
1501		dma_set_residue(txstate, bytes);
1502	}
1503
1504	dev_vdbg(chan2dev(chan), "tx_status %d: cookie = %d residue = %d\n",
1505		 ret, cookie, bytes);
1506
1507	return ret;
1508}
1509
1510/**
1511 * atc_issue_pending - try to finish work
1512 * @chan: target DMA channel
1513 */
1514static void atc_issue_pending(struct dma_chan *chan)
1515{
1516	struct at_dma_chan	*atchan = to_at_dma_chan(chan);
 
1517
1518	dev_vdbg(chan2dev(chan), "issue_pending\n");
1519
1520	/* Not needed for cyclic transfers */
1521	if (atc_chan_is_cyclic(atchan))
1522		return;
1523
 
1524	atc_advance_work(atchan);
 
1525}
1526
1527/**
1528 * atc_alloc_chan_resources - allocate resources for DMA channel
1529 * @chan: allocate descriptor resources for this channel
 
1530 *
1531 * return - the number of allocated descriptors
1532 */
1533static int atc_alloc_chan_resources(struct dma_chan *chan)
1534{
1535	struct at_dma_chan	*atchan = to_at_dma_chan(chan);
1536	struct at_dma		*atdma = to_at_dma(chan->device);
1537	struct at_desc		*desc;
1538	struct at_dma_slave	*atslave;
 
1539	int			i;
1540	u32			cfg;
 
1541
1542	dev_vdbg(chan2dev(chan), "alloc_chan_resources\n");
1543
1544	/* ASSERT:  channel is idle */
1545	if (atc_chan_is_enabled(atchan)) {
1546		dev_dbg(chan2dev(chan), "DMA channel not idle ?\n");
1547		return -EIO;
1548	}
1549
1550	if (!list_empty(&atchan->free_list)) {
1551		dev_dbg(chan2dev(chan), "can't allocate channel resources (channel not freed from a previous use)\n");
1552		return -EIO;
1553	}
1554
1555	cfg = ATC_DEFAULT_CFG;
1556
1557	atslave = chan->private;
1558	if (atslave) {
1559		/*
1560		 * We need controller-specific data to set up slave
1561		 * transfers.
1562		 */
1563		BUG_ON(!atslave->dma_dev || atslave->dma_dev != atdma->dma_common.dev);
1564
1565		/* if cfg configuration specified take it instead of default */
1566		if (atslave->cfg)
1567			cfg = atslave->cfg;
1568	}
1569
 
 
 
 
 
1570	/* Allocate initial pool of descriptors */
1571	for (i = 0; i < init_nr_desc_per_channel; i++) {
1572		desc = atc_alloc_descriptor(chan, GFP_KERNEL);
1573		if (!desc) {
1574			dev_err(atdma->dma_common.dev,
1575				"Only %d initial descriptors\n", i);
1576			break;
1577		}
1578		list_add_tail(&desc->desc_node, &atchan->free_list);
1579	}
1580
 
 
 
1581	dma_cookie_init(chan);
 
1582
1583	/* channel parameters */
1584	channel_writel(atchan, CFG, cfg);
1585
1586	dev_dbg(chan2dev(chan),
1587		"alloc_chan_resources: allocated %d descriptors\n", i);
 
1588
1589	return i;
1590}
1591
1592/**
1593 * atc_free_chan_resources - free all channel resources
1594 * @chan: DMA channel
1595 */
1596static void atc_free_chan_resources(struct dma_chan *chan)
1597{
1598	struct at_dma_chan	*atchan = to_at_dma_chan(chan);
1599	struct at_dma		*atdma = to_at_dma(chan->device);
1600	struct at_desc		*desc, *_desc;
1601	LIST_HEAD(list);
1602
 
 
 
1603	/* ASSERT:  channel is idle */
1604	BUG_ON(!list_empty(&atchan->active_list));
1605	BUG_ON(!list_empty(&atchan->queue));
1606	BUG_ON(atc_chan_is_enabled(atchan));
1607
1608	list_for_each_entry_safe(desc, _desc, &atchan->free_list, desc_node) {
1609		dev_vdbg(chan2dev(chan), "  freeing descriptor %p\n", desc);
1610		list_del(&desc->desc_node);
1611		/* free link descriptor */
1612		dma_pool_free(atdma->dma_desc_pool, desc, desc->txd.phys);
1613	}
1614	list_splice_init(&atchan->free_list, &list);
 
1615	atchan->status = 0;
1616
1617	/*
1618	 * Free atslave allocated in at_dma_xlate()
1619	 */
1620	kfree(chan->private);
1621	chan->private = NULL;
1622
1623	dev_vdbg(chan2dev(chan), "free_chan_resources: done\n");
1624}
1625
1626#ifdef CONFIG_OF
1627static bool at_dma_filter(struct dma_chan *chan, void *slave)
1628{
1629	struct at_dma_slave *atslave = slave;
1630
1631	if (atslave->dma_dev == chan->device->dev) {
1632		chan->private = atslave;
1633		return true;
1634	} else {
1635		return false;
1636	}
1637}
1638
1639static struct dma_chan *at_dma_xlate(struct of_phandle_args *dma_spec,
1640				     struct of_dma *of_dma)
1641{
1642	struct dma_chan *chan;
1643	struct at_dma_chan *atchan;
1644	struct at_dma_slave *atslave;
1645	dma_cap_mask_t mask;
1646	unsigned int per_id;
1647	struct platform_device *dmac_pdev;
1648
1649	if (dma_spec->args_count != 2)
1650		return NULL;
1651
1652	dmac_pdev = of_find_device_by_node(dma_spec->np);
1653	if (!dmac_pdev)
1654		return NULL;
1655
1656	dma_cap_zero(mask);
1657	dma_cap_set(DMA_SLAVE, mask);
1658
1659	atslave = kmalloc(sizeof(*atslave), GFP_KERNEL);
1660	if (!atslave) {
1661		put_device(&dmac_pdev->dev);
1662		return NULL;
1663	}
1664
1665	atslave->cfg = ATC_DST_H2SEL_HW | ATC_SRC_H2SEL_HW;
1666	/*
1667	 * We can fill both SRC_PER and DST_PER, one of these fields will be
1668	 * ignored depending on DMA transfer direction.
1669	 */
1670	per_id = dma_spec->args[1] & AT91_DMA_CFG_PER_ID_MASK;
1671	atslave->cfg |= ATC_DST_PER_MSB(per_id) | ATC_DST_PER(per_id)
1672		     | ATC_SRC_PER_MSB(per_id) | ATC_SRC_PER(per_id);
1673	/*
1674	 * We have to translate the value we get from the device tree since
1675	 * the half FIFO configuration value had to be 0 to keep backward
1676	 * compatibility.
1677	 */
1678	switch (dma_spec->args[1] & AT91_DMA_CFG_FIFOCFG_MASK) {
1679	case AT91_DMA_CFG_FIFOCFG_ALAP:
1680		atslave->cfg |= ATC_FIFOCFG_LARGESTBURST;
1681		break;
1682	case AT91_DMA_CFG_FIFOCFG_ASAP:
1683		atslave->cfg |= ATC_FIFOCFG_ENOUGHSPACE;
1684		break;
1685	case AT91_DMA_CFG_FIFOCFG_HALF:
1686	default:
1687		atslave->cfg |= ATC_FIFOCFG_HALFFIFO;
1688	}
1689	atslave->dma_dev = &dmac_pdev->dev;
1690
1691	chan = dma_request_channel(mask, at_dma_filter, atslave);
1692	if (!chan) {
1693		put_device(&dmac_pdev->dev);
1694		kfree(atslave);
1695		return NULL;
1696	}
1697
1698	atchan = to_at_dma_chan(chan);
1699	atchan->per_if = dma_spec->args[0] & 0xff;
1700	atchan->mem_if = (dma_spec->args[0] >> 16) & 0xff;
1701
1702	return chan;
1703}
1704#else
1705static struct dma_chan *at_dma_xlate(struct of_phandle_args *dma_spec,
1706				     struct of_dma *of_dma)
1707{
1708	return NULL;
1709}
1710#endif
1711
1712/*--  Module Management  -----------------------------------------------*/
1713
1714/* cap_mask is a multi-u32 bitfield, fill it with proper C code. */
1715static struct at_dma_platform_data at91sam9rl_config = {
1716	.nr_channels = 2,
1717};
1718static struct at_dma_platform_data at91sam9g45_config = {
1719	.nr_channels = 8,
1720};
1721
1722#if defined(CONFIG_OF)
1723static const struct of_device_id atmel_dma_dt_ids[] = {
1724	{
1725		.compatible = "atmel,at91sam9rl-dma",
1726		.data = &at91sam9rl_config,
1727	}, {
1728		.compatible = "atmel,at91sam9g45-dma",
1729		.data = &at91sam9g45_config,
1730	}, {
1731		/* sentinel */
1732	}
1733};
1734
1735MODULE_DEVICE_TABLE(of, atmel_dma_dt_ids);
1736#endif
1737
1738static const struct platform_device_id atdma_devtypes[] = {
1739	{
1740		.name = "at91sam9rl_dma",
1741		.driver_data = (unsigned long) &at91sam9rl_config,
1742	}, {
1743		.name = "at91sam9g45_dma",
1744		.driver_data = (unsigned long) &at91sam9g45_config,
1745	}, {
1746		/* sentinel */
1747	}
1748};
1749
1750static inline const struct at_dma_platform_data * __init at_dma_get_driver_data(
1751						struct platform_device *pdev)
1752{
1753	if (pdev->dev.of_node) {
1754		const struct of_device_id *match;
1755		match = of_match_node(atmel_dma_dt_ids, pdev->dev.of_node);
1756		if (match == NULL)
1757			return NULL;
1758		return match->data;
1759	}
1760	return (struct at_dma_platform_data *)
1761			platform_get_device_id(pdev)->driver_data;
1762}
1763
1764/**
1765 * at_dma_off - disable DMA controller
1766 * @atdma: the Atmel HDAMC device
1767 */
1768static void at_dma_off(struct at_dma *atdma)
1769{
1770	dma_writel(atdma, EN, 0);
1771
1772	/* disable all interrupts */
1773	dma_writel(atdma, EBCIDR, -1L);
1774
1775	/* confirm that all channels are disabled */
1776	while (dma_readl(atdma, CHSR) & atdma->all_chan_mask)
1777		cpu_relax();
1778}
1779
1780static int __init at_dma_probe(struct platform_device *pdev)
1781{
1782	struct resource		*io;
1783	struct at_dma		*atdma;
1784	size_t			size;
1785	int			irq;
1786	int			err;
1787	int			i;
1788	const struct at_dma_platform_data *plat_dat;
1789
1790	/* setup platform data for each SoC */
1791	dma_cap_set(DMA_MEMCPY, at91sam9rl_config.cap_mask);
1792	dma_cap_set(DMA_INTERLEAVE, at91sam9g45_config.cap_mask);
1793	dma_cap_set(DMA_MEMCPY, at91sam9g45_config.cap_mask);
1794	dma_cap_set(DMA_MEMSET, at91sam9g45_config.cap_mask);
1795	dma_cap_set(DMA_MEMSET_SG, at91sam9g45_config.cap_mask);
1796	dma_cap_set(DMA_PRIVATE, at91sam9g45_config.cap_mask);
1797	dma_cap_set(DMA_SLAVE, at91sam9g45_config.cap_mask);
1798
1799	/* get DMA parameters from controller type */
1800	plat_dat = at_dma_get_driver_data(pdev);
1801	if (!plat_dat)
1802		return -ENODEV;
1803
1804	io = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1805	if (!io)
1806		return -EINVAL;
1807
1808	irq = platform_get_irq(pdev, 0);
1809	if (irq < 0)
1810		return irq;
1811
1812	size = sizeof(struct at_dma);
1813	size += plat_dat->nr_channels * sizeof(struct at_dma_chan);
1814	atdma = kzalloc(size, GFP_KERNEL);
1815	if (!atdma)
1816		return -ENOMEM;
1817
1818	/* discover transaction capabilities */
1819	atdma->dma_common.cap_mask = plat_dat->cap_mask;
1820	atdma->all_chan_mask = (1 << plat_dat->nr_channels) - 1;
1821
1822	size = resource_size(io);
1823	if (!request_mem_region(io->start, size, pdev->dev.driver->name)) {
1824		err = -EBUSY;
1825		goto err_kfree;
1826	}
1827
1828	atdma->regs = ioremap(io->start, size);
1829	if (!atdma->regs) {
1830		err = -ENOMEM;
1831		goto err_release_r;
1832	}
1833
1834	atdma->clk = clk_get(&pdev->dev, "dma_clk");
1835	if (IS_ERR(atdma->clk)) {
1836		err = PTR_ERR(atdma->clk);
1837		goto err_clk;
1838	}
1839	err = clk_prepare_enable(atdma->clk);
1840	if (err)
1841		goto err_clk_prepare;
1842
1843	/* force dma off, just in case */
1844	at_dma_off(atdma);
1845
1846	err = request_irq(irq, at_dma_interrupt, 0, "at_hdmac", atdma);
1847	if (err)
1848		goto err_irq;
1849
1850	platform_set_drvdata(pdev, atdma);
1851
1852	/* create a pool of consistent memory blocks for hardware descriptors */
1853	atdma->dma_desc_pool = dma_pool_create("at_hdmac_desc_pool",
1854			&pdev->dev, sizeof(struct at_desc),
1855			4 /* word alignment */, 0);
1856	if (!atdma->dma_desc_pool) {
1857		dev_err(&pdev->dev, "No memory for descriptors dma pool\n");
1858		err = -ENOMEM;
1859		goto err_desc_pool_create;
1860	}
1861
1862	/* create a pool of consistent memory blocks for memset blocks */
1863	atdma->memset_pool = dma_pool_create("at_hdmac_memset_pool",
1864					     &pdev->dev, sizeof(int), 4, 0);
1865	if (!atdma->memset_pool) {
1866		dev_err(&pdev->dev, "No memory for memset dma pool\n");
1867		err = -ENOMEM;
1868		goto err_memset_pool_create;
1869	}
1870
1871	/* clear any pending interrupt */
1872	while (dma_readl(atdma, EBCISR))
1873		cpu_relax();
1874
1875	/* initialize channels related values */
1876	INIT_LIST_HEAD(&atdma->dma_common.channels);
1877	for (i = 0; i < plat_dat->nr_channels; i++) {
1878		struct at_dma_chan	*atchan = &atdma->chan[i];
1879
1880		atchan->mem_if = AT_DMA_MEM_IF;
1881		atchan->per_if = AT_DMA_PER_IF;
1882		atchan->chan_common.device = &atdma->dma_common;
1883		dma_cookie_init(&atchan->chan_common);
1884		list_add_tail(&atchan->chan_common.device_node,
1885				&atdma->dma_common.channels);
1886
1887		atchan->ch_regs = atdma->regs + ch_regs(i);
1888		spin_lock_init(&atchan->lock);
1889		atchan->mask = 1 << i;
1890
1891		INIT_LIST_HEAD(&atchan->active_list);
1892		INIT_LIST_HEAD(&atchan->queue);
1893		INIT_LIST_HEAD(&atchan->free_list);
1894
1895		tasklet_init(&atchan->tasklet, atc_tasklet,
1896				(unsigned long)atchan);
1897		atc_enable_chan_irq(atdma, i);
1898	}
1899
1900	/* set base routines */
1901	atdma->dma_common.device_alloc_chan_resources = atc_alloc_chan_resources;
1902	atdma->dma_common.device_free_chan_resources = atc_free_chan_resources;
1903	atdma->dma_common.device_tx_status = atc_tx_status;
1904	atdma->dma_common.device_issue_pending = atc_issue_pending;
1905	atdma->dma_common.dev = &pdev->dev;
1906
1907	/* set prep routines based on capability */
1908	if (dma_has_cap(DMA_INTERLEAVE, atdma->dma_common.cap_mask))
1909		atdma->dma_common.device_prep_interleaved_dma = atc_prep_dma_interleaved;
1910
1911	if (dma_has_cap(DMA_MEMCPY, atdma->dma_common.cap_mask))
1912		atdma->dma_common.device_prep_dma_memcpy = atc_prep_dma_memcpy;
1913
1914	if (dma_has_cap(DMA_MEMSET, atdma->dma_common.cap_mask)) {
1915		atdma->dma_common.device_prep_dma_memset = atc_prep_dma_memset;
1916		atdma->dma_common.device_prep_dma_memset_sg = atc_prep_dma_memset_sg;
1917		atdma->dma_common.fill_align = DMAENGINE_ALIGN_4_BYTES;
1918	}
1919
1920	if (dma_has_cap(DMA_SLAVE, atdma->dma_common.cap_mask)) {
1921		atdma->dma_common.device_prep_slave_sg = atc_prep_slave_sg;
1922		/* controller can do slave DMA: can trigger cyclic transfers */
1923		dma_cap_set(DMA_CYCLIC, atdma->dma_common.cap_mask);
1924		atdma->dma_common.device_prep_dma_cyclic = atc_prep_dma_cyclic;
1925		atdma->dma_common.device_config = atc_config;
1926		atdma->dma_common.device_pause = atc_pause;
1927		atdma->dma_common.device_resume = atc_resume;
1928		atdma->dma_common.device_terminate_all = atc_terminate_all;
1929		atdma->dma_common.src_addr_widths = ATC_DMA_BUSWIDTHS;
1930		atdma->dma_common.dst_addr_widths = ATC_DMA_BUSWIDTHS;
1931		atdma->dma_common.directions = BIT(DMA_DEV_TO_MEM) | BIT(DMA_MEM_TO_DEV);
1932		atdma->dma_common.residue_granularity = DMA_RESIDUE_GRANULARITY_BURST;
1933	}
1934
1935	dma_writel(atdma, EN, AT_DMA_ENABLE);
1936
1937	dev_info(&pdev->dev, "Atmel AHB DMA Controller ( %s%s%s), %d channels\n",
1938	  dma_has_cap(DMA_MEMCPY, atdma->dma_common.cap_mask) ? "cpy " : "",
1939	  dma_has_cap(DMA_MEMSET, atdma->dma_common.cap_mask) ? "set " : "",
1940	  dma_has_cap(DMA_SLAVE, atdma->dma_common.cap_mask)  ? "slave " : "",
1941	  plat_dat->nr_channels);
1942
1943	dma_async_device_register(&atdma->dma_common);
1944
1945	/*
1946	 * Do not return an error if the dmac node is not present in order to
1947	 * not break the existing way of requesting channel with
1948	 * dma_request_channel().
1949	 */
1950	if (pdev->dev.of_node) {
1951		err = of_dma_controller_register(pdev->dev.of_node,
1952						 at_dma_xlate, atdma);
1953		if (err) {
1954			dev_err(&pdev->dev, "could not register of_dma_controller\n");
1955			goto err_of_dma_controller_register;
1956		}
1957	}
1958
1959	return 0;
1960
1961err_of_dma_controller_register:
1962	dma_async_device_unregister(&atdma->dma_common);
1963	dma_pool_destroy(atdma->memset_pool);
1964err_memset_pool_create:
1965	dma_pool_destroy(atdma->dma_desc_pool);
1966err_desc_pool_create:
1967	free_irq(platform_get_irq(pdev, 0), atdma);
1968err_irq:
1969	clk_disable_unprepare(atdma->clk);
1970err_clk_prepare:
1971	clk_put(atdma->clk);
1972err_clk:
1973	iounmap(atdma->regs);
1974	atdma->regs = NULL;
1975err_release_r:
1976	release_mem_region(io->start, size);
1977err_kfree:
1978	kfree(atdma);
1979	return err;
1980}
1981
1982static int at_dma_remove(struct platform_device *pdev)
1983{
1984	struct at_dma		*atdma = platform_get_drvdata(pdev);
1985	struct dma_chan		*chan, *_chan;
1986	struct resource		*io;
1987
1988	at_dma_off(atdma);
1989	if (pdev->dev.of_node)
1990		of_dma_controller_free(pdev->dev.of_node);
1991	dma_async_device_unregister(&atdma->dma_common);
1992
1993	dma_pool_destroy(atdma->memset_pool);
1994	dma_pool_destroy(atdma->dma_desc_pool);
1995	free_irq(platform_get_irq(pdev, 0), atdma);
1996
1997	list_for_each_entry_safe(chan, _chan, &atdma->dma_common.channels,
1998			device_node) {
1999		struct at_dma_chan	*atchan = to_at_dma_chan(chan);
2000
2001		/* Disable interrupts */
2002		atc_disable_chan_irq(atdma, chan->chan_id);
2003
2004		tasklet_kill(&atchan->tasklet);
2005		list_del(&chan->device_node);
2006	}
2007
2008	clk_disable_unprepare(atdma->clk);
2009	clk_put(atdma->clk);
2010
2011	iounmap(atdma->regs);
2012	atdma->regs = NULL;
2013
2014	io = platform_get_resource(pdev, IORESOURCE_MEM, 0);
2015	release_mem_region(io->start, resource_size(io));
2016
2017	kfree(atdma);
2018
2019	return 0;
2020}
2021
2022static void at_dma_shutdown(struct platform_device *pdev)
2023{
2024	struct at_dma	*atdma = platform_get_drvdata(pdev);
2025
2026	at_dma_off(platform_get_drvdata(pdev));
2027	clk_disable_unprepare(atdma->clk);
2028}
2029
2030static int at_dma_prepare(struct device *dev)
2031{
2032	struct at_dma *atdma = dev_get_drvdata(dev);
2033	struct dma_chan *chan, *_chan;
2034
2035	list_for_each_entry_safe(chan, _chan, &atdma->dma_common.channels,
2036			device_node) {
2037		struct at_dma_chan *atchan = to_at_dma_chan(chan);
2038		/* wait for transaction completion (except in cyclic case) */
2039		if (atc_chan_is_enabled(atchan) && !atc_chan_is_cyclic(atchan))
2040			return -EAGAIN;
2041	}
2042	return 0;
2043}
2044
2045static void atc_suspend_cyclic(struct at_dma_chan *atchan)
2046{
2047	struct dma_chan	*chan = &atchan->chan_common;
2048
2049	/* Channel should be paused by user
2050	 * do it anyway even if it is not done already */
2051	if (!atc_chan_is_paused(atchan)) {
2052		dev_warn(chan2dev(chan),
2053		"cyclic channel not paused, should be done by channel user\n");
2054		atc_pause(chan);
2055	}
2056
2057	/* now preserve additional data for cyclic operations */
2058	/* next descriptor address in the cyclic list */
2059	atchan->save_dscr = channel_readl(atchan, DSCR);
2060
2061	vdbg_dump_regs(atchan);
2062}
2063
2064static int at_dma_suspend_noirq(struct device *dev)
2065{
2066	struct at_dma *atdma = dev_get_drvdata(dev);
2067	struct dma_chan *chan, *_chan;
2068
2069	/* preserve data */
2070	list_for_each_entry_safe(chan, _chan, &atdma->dma_common.channels,
2071			device_node) {
2072		struct at_dma_chan *atchan = to_at_dma_chan(chan);
2073
2074		if (atc_chan_is_cyclic(atchan))
2075			atc_suspend_cyclic(atchan);
2076		atchan->save_cfg = channel_readl(atchan, CFG);
2077	}
2078	atdma->save_imr = dma_readl(atdma, EBCIMR);
2079
2080	/* disable DMA controller */
2081	at_dma_off(atdma);
2082	clk_disable_unprepare(atdma->clk);
2083	return 0;
2084}
2085
2086static void atc_resume_cyclic(struct at_dma_chan *atchan)
2087{
2088	struct at_dma	*atdma = to_at_dma(atchan->chan_common.device);
2089
2090	/* restore channel status for cyclic descriptors list:
2091	 * next descriptor in the cyclic list at the time of suspend */
2092	channel_writel(atchan, SADDR, 0);
2093	channel_writel(atchan, DADDR, 0);
2094	channel_writel(atchan, CTRLA, 0);
2095	channel_writel(atchan, CTRLB, 0);
2096	channel_writel(atchan, DSCR, atchan->save_dscr);
2097	dma_writel(atdma, CHER, atchan->mask);
2098
2099	/* channel pause status should be removed by channel user
2100	 * We cannot take the initiative to do it here */
2101
2102	vdbg_dump_regs(atchan);
2103}
2104
2105static int at_dma_resume_noirq(struct device *dev)
2106{
2107	struct at_dma *atdma = dev_get_drvdata(dev);
2108	struct dma_chan *chan, *_chan;
2109
2110	/* bring back DMA controller */
2111	clk_prepare_enable(atdma->clk);
2112	dma_writel(atdma, EN, AT_DMA_ENABLE);
2113
2114	/* clear any pending interrupt */
2115	while (dma_readl(atdma, EBCISR))
2116		cpu_relax();
2117
2118	/* restore saved data */
2119	dma_writel(atdma, EBCIER, atdma->save_imr);
2120	list_for_each_entry_safe(chan, _chan, &atdma->dma_common.channels,
2121			device_node) {
2122		struct at_dma_chan *atchan = to_at_dma_chan(chan);
2123
2124		channel_writel(atchan, CFG, atchan->save_cfg);
2125		if (atc_chan_is_cyclic(atchan))
2126			atc_resume_cyclic(atchan);
2127	}
2128	return 0;
2129}
2130
2131static const struct dev_pm_ops at_dma_dev_pm_ops = {
2132	.prepare = at_dma_prepare,
2133	.suspend_noirq = at_dma_suspend_noirq,
2134	.resume_noirq = at_dma_resume_noirq,
2135};
2136
2137static struct platform_driver at_dma_driver = {
2138	.remove		= at_dma_remove,
2139	.shutdown	= at_dma_shutdown,
2140	.id_table	= atdma_devtypes,
2141	.driver = {
2142		.name	= "at_hdmac",
2143		.pm	= &at_dma_dev_pm_ops,
2144		.of_match_table	= of_match_ptr(atmel_dma_dt_ids),
2145	},
2146};
2147
2148static int __init at_dma_init(void)
2149{
2150	return platform_driver_probe(&at_dma_driver, at_dma_probe);
2151}
2152subsys_initcall(at_dma_init);
2153
2154static void __exit at_dma_exit(void)
2155{
2156	platform_driver_unregister(&at_dma_driver);
2157}
2158module_exit(at_dma_exit);
2159
2160MODULE_DESCRIPTION("Atmel AHB DMA Controller driver");
2161MODULE_AUTHOR("Nicolas Ferre <nicolas.ferre@atmel.com>");
2162MODULE_LICENSE("GPL");
2163MODULE_ALIAS("platform:at_hdmac");