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   1/*
   2 * Copyright (C) 2013-2014 Allwinner Tech Co., Ltd
   3 * Author: Sugar <shuge@allwinnertech.com>
   4 *
   5 * Copyright (C) 2014 Maxime Ripard
   6 * Maxime Ripard <maxime.ripard@free-electrons.com>
   7 *
   8 * This program is free software; you can redistribute it and/or modify
   9 * it under the terms of the GNU General Public License as published by
  10 * the Free Software Foundation; either version 2 of the License, or
  11 * (at your option) any later version.
  12 */
  13
  14#include <linux/clk.h>
  15#include <linux/delay.h>
  16#include <linux/dmaengine.h>
  17#include <linux/dmapool.h>
  18#include <linux/interrupt.h>
  19#include <linux/module.h>
  20#include <linux/of_dma.h>
  21#include <linux/of_device.h>
  22#include <linux/platform_device.h>
  23#include <linux/reset.h>
  24#include <linux/slab.h>
  25#include <linux/types.h>
  26
  27#include "virt-dma.h"
  28
  29/*
  30 * Common registers
  31 */
  32#define DMA_IRQ_EN(x)		((x) * 0x04)
  33#define DMA_IRQ_HALF			BIT(0)
  34#define DMA_IRQ_PKG			BIT(1)
  35#define DMA_IRQ_QUEUE			BIT(2)
  36
  37#define DMA_IRQ_CHAN_NR			8
  38#define DMA_IRQ_CHAN_WIDTH		4
  39
  40
  41#define DMA_IRQ_STAT(x)		((x) * 0x04 + 0x10)
  42
  43#define DMA_STAT		0x30
  44
  45/*
  46 * sun8i specific registers
  47 */
  48#define SUN8I_DMA_GATE		0x20
  49#define SUN8I_DMA_GATE_ENABLE	0x4
  50
  51/*
  52 * Channels specific registers
  53 */
  54#define DMA_CHAN_ENABLE		0x00
  55#define DMA_CHAN_ENABLE_START		BIT(0)
  56#define DMA_CHAN_ENABLE_STOP		0
  57
  58#define DMA_CHAN_PAUSE		0x04
  59#define DMA_CHAN_PAUSE_PAUSE		BIT(1)
  60#define DMA_CHAN_PAUSE_RESUME		0
  61
  62#define DMA_CHAN_LLI_ADDR	0x08
  63
  64#define DMA_CHAN_CUR_CFG	0x0c
  65#define DMA_CHAN_CFG_SRC_DRQ(x)		((x) & 0x1f)
  66#define DMA_CHAN_CFG_SRC_IO_MODE	BIT(5)
  67#define DMA_CHAN_CFG_SRC_LINEAR_MODE	(0 << 5)
  68#define DMA_CHAN_CFG_SRC_BURST(x)	(((x) & 0x3) << 7)
  69#define DMA_CHAN_CFG_SRC_WIDTH(x)	(((x) & 0x3) << 9)
  70
  71#define DMA_CHAN_CFG_DST_DRQ(x)		(DMA_CHAN_CFG_SRC_DRQ(x) << 16)
  72#define DMA_CHAN_CFG_DST_IO_MODE	(DMA_CHAN_CFG_SRC_IO_MODE << 16)
  73#define DMA_CHAN_CFG_DST_LINEAR_MODE	(DMA_CHAN_CFG_SRC_LINEAR_MODE << 16)
  74#define DMA_CHAN_CFG_DST_BURST(x)	(DMA_CHAN_CFG_SRC_BURST(x) << 16)
  75#define DMA_CHAN_CFG_DST_WIDTH(x)	(DMA_CHAN_CFG_SRC_WIDTH(x) << 16)
  76
  77#define DMA_CHAN_CUR_SRC	0x10
  78
  79#define DMA_CHAN_CUR_DST	0x14
  80
  81#define DMA_CHAN_CUR_CNT	0x18
  82
  83#define DMA_CHAN_CUR_PARA	0x1c
  84
  85
  86/*
  87 * Various hardware related defines
  88 */
  89#define LLI_LAST_ITEM	0xfffff800
  90#define NORMAL_WAIT	8
  91#define DRQ_SDRAM	1
  92
  93/*
  94 * Hardware channels / ports representation
  95 *
  96 * The hardware is used in several SoCs, with differing numbers
  97 * of channels and endpoints. This structure ties those numbers
  98 * to a certain compatible string.
  99 */
 100struct sun6i_dma_config {
 101	u32 nr_max_channels;
 102	u32 nr_max_requests;
 103	u32 nr_max_vchans;
 104};
 105
 106/*
 107 * Hardware representation of the LLI
 108 *
 109 * The hardware will be fed the physical address of this structure,
 110 * and read its content in order to start the transfer.
 111 */
 112struct sun6i_dma_lli {
 113	u32			cfg;
 114	u32			src;
 115	u32			dst;
 116	u32			len;
 117	u32			para;
 118	u32			p_lli_next;
 119
 120	/*
 121	 * This field is not used by the DMA controller, but will be
 122	 * used by the CPU to go through the list (mostly for dumping
 123	 * or freeing it).
 124	 */
 125	struct sun6i_dma_lli	*v_lli_next;
 126};
 127
 128
 129struct sun6i_desc {
 130	struct virt_dma_desc	vd;
 131	dma_addr_t		p_lli;
 132	struct sun6i_dma_lli	*v_lli;
 133};
 134
 135struct sun6i_pchan {
 136	u32			idx;
 137	void __iomem		*base;
 138	struct sun6i_vchan	*vchan;
 139	struct sun6i_desc	*desc;
 140	struct sun6i_desc	*done;
 141};
 142
 143struct sun6i_vchan {
 144	struct virt_dma_chan	vc;
 145	struct list_head	node;
 146	struct dma_slave_config	cfg;
 147	struct sun6i_pchan	*phy;
 148	u8			port;
 149	u8			irq_type;
 150	bool			cyclic;
 151};
 152
 153struct sun6i_dma_dev {
 154	struct dma_device	slave;
 155	void __iomem		*base;
 156	struct clk		*clk;
 157	int			irq;
 158	spinlock_t		lock;
 159	struct reset_control	*rstc;
 160	struct tasklet_struct	task;
 161	atomic_t		tasklet_shutdown;
 162	struct list_head	pending;
 163	struct dma_pool		*pool;
 164	struct sun6i_pchan	*pchans;
 165	struct sun6i_vchan	*vchans;
 166	const struct sun6i_dma_config *cfg;
 167};
 168
 169static struct device *chan2dev(struct dma_chan *chan)
 170{
 171	return &chan->dev->device;
 172}
 173
 174static inline struct sun6i_dma_dev *to_sun6i_dma_dev(struct dma_device *d)
 175{
 176	return container_of(d, struct sun6i_dma_dev, slave);
 177}
 178
 179static inline struct sun6i_vchan *to_sun6i_vchan(struct dma_chan *chan)
 180{
 181	return container_of(chan, struct sun6i_vchan, vc.chan);
 182}
 183
 184static inline struct sun6i_desc *
 185to_sun6i_desc(struct dma_async_tx_descriptor *tx)
 186{
 187	return container_of(tx, struct sun6i_desc, vd.tx);
 188}
 189
 190static inline void sun6i_dma_dump_com_regs(struct sun6i_dma_dev *sdev)
 191{
 192	dev_dbg(sdev->slave.dev, "Common register:\n"
 193		"\tmask0(%04x): 0x%08x\n"
 194		"\tmask1(%04x): 0x%08x\n"
 195		"\tpend0(%04x): 0x%08x\n"
 196		"\tpend1(%04x): 0x%08x\n"
 197		"\tstats(%04x): 0x%08x\n",
 198		DMA_IRQ_EN(0), readl(sdev->base + DMA_IRQ_EN(0)),
 199		DMA_IRQ_EN(1), readl(sdev->base + DMA_IRQ_EN(1)),
 200		DMA_IRQ_STAT(0), readl(sdev->base + DMA_IRQ_STAT(0)),
 201		DMA_IRQ_STAT(1), readl(sdev->base + DMA_IRQ_STAT(1)),
 202		DMA_STAT, readl(sdev->base + DMA_STAT));
 203}
 204
 205static inline void sun6i_dma_dump_chan_regs(struct sun6i_dma_dev *sdev,
 206					    struct sun6i_pchan *pchan)
 207{
 208	phys_addr_t reg = virt_to_phys(pchan->base);
 209
 210	dev_dbg(sdev->slave.dev, "Chan %d reg: %pa\n"
 211		"\t___en(%04x): \t0x%08x\n"
 212		"\tpause(%04x): \t0x%08x\n"
 213		"\tstart(%04x): \t0x%08x\n"
 214		"\t__cfg(%04x): \t0x%08x\n"
 215		"\t__src(%04x): \t0x%08x\n"
 216		"\t__dst(%04x): \t0x%08x\n"
 217		"\tcount(%04x): \t0x%08x\n"
 218		"\t_para(%04x): \t0x%08x\n\n",
 219		pchan->idx, &reg,
 220		DMA_CHAN_ENABLE,
 221		readl(pchan->base + DMA_CHAN_ENABLE),
 222		DMA_CHAN_PAUSE,
 223		readl(pchan->base + DMA_CHAN_PAUSE),
 224		DMA_CHAN_LLI_ADDR,
 225		readl(pchan->base + DMA_CHAN_LLI_ADDR),
 226		DMA_CHAN_CUR_CFG,
 227		readl(pchan->base + DMA_CHAN_CUR_CFG),
 228		DMA_CHAN_CUR_SRC,
 229		readl(pchan->base + DMA_CHAN_CUR_SRC),
 230		DMA_CHAN_CUR_DST,
 231		readl(pchan->base + DMA_CHAN_CUR_DST),
 232		DMA_CHAN_CUR_CNT,
 233		readl(pchan->base + DMA_CHAN_CUR_CNT),
 234		DMA_CHAN_CUR_PARA,
 235		readl(pchan->base + DMA_CHAN_CUR_PARA));
 236}
 237
 238static inline s8 convert_burst(u32 maxburst)
 239{
 240	switch (maxburst) {
 241	case 1:
 242		return 0;
 243	case 8:
 244		return 2;
 245	default:
 246		return -EINVAL;
 247	}
 248}
 249
 250static inline s8 convert_buswidth(enum dma_slave_buswidth addr_width)
 251{
 252	if ((addr_width < DMA_SLAVE_BUSWIDTH_1_BYTE) ||
 253	    (addr_width > DMA_SLAVE_BUSWIDTH_4_BYTES))
 254		return -EINVAL;
 255
 256	return addr_width >> 1;
 257}
 258
 259static size_t sun6i_get_chan_size(struct sun6i_pchan *pchan)
 260{
 261	struct sun6i_desc *txd = pchan->desc;
 262	struct sun6i_dma_lli *lli;
 263	size_t bytes;
 264	dma_addr_t pos;
 265
 266	pos = readl(pchan->base + DMA_CHAN_LLI_ADDR);
 267	bytes = readl(pchan->base + DMA_CHAN_CUR_CNT);
 268
 269	if (pos == LLI_LAST_ITEM)
 270		return bytes;
 271
 272	for (lli = txd->v_lli; lli; lli = lli->v_lli_next) {
 273		if (lli->p_lli_next == pos) {
 274			for (lli = lli->v_lli_next; lli; lli = lli->v_lli_next)
 275				bytes += lli->len;
 276			break;
 277		}
 278	}
 279
 280	return bytes;
 281}
 282
 283static void *sun6i_dma_lli_add(struct sun6i_dma_lli *prev,
 284			       struct sun6i_dma_lli *next,
 285			       dma_addr_t next_phy,
 286			       struct sun6i_desc *txd)
 287{
 288	if ((!prev && !txd) || !next)
 289		return NULL;
 290
 291	if (!prev) {
 292		txd->p_lli = next_phy;
 293		txd->v_lli = next;
 294	} else {
 295		prev->p_lli_next = next_phy;
 296		prev->v_lli_next = next;
 297	}
 298
 299	next->p_lli_next = LLI_LAST_ITEM;
 300	next->v_lli_next = NULL;
 301
 302	return next;
 303}
 304
 305static inline void sun6i_dma_dump_lli(struct sun6i_vchan *vchan,
 306				      struct sun6i_dma_lli *lli)
 307{
 308	phys_addr_t p_lli = virt_to_phys(lli);
 309
 310	dev_dbg(chan2dev(&vchan->vc.chan),
 311		"\n\tdesc:   p - %pa v - 0x%p\n"
 312		"\t\tc - 0x%08x s - 0x%08x d - 0x%08x\n"
 313		"\t\tl - 0x%08x p - 0x%08x n - 0x%08x\n",
 314		&p_lli, lli,
 315		lli->cfg, lli->src, lli->dst,
 316		lli->len, lli->para, lli->p_lli_next);
 317}
 318
 319static void sun6i_dma_free_desc(struct virt_dma_desc *vd)
 320{
 321	struct sun6i_desc *txd = to_sun6i_desc(&vd->tx);
 322	struct sun6i_dma_dev *sdev = to_sun6i_dma_dev(vd->tx.chan->device);
 323	struct sun6i_dma_lli *v_lli, *v_next;
 324	dma_addr_t p_lli, p_next;
 325
 326	if (unlikely(!txd))
 327		return;
 328
 329	p_lli = txd->p_lli;
 330	v_lli = txd->v_lli;
 331
 332	while (v_lli) {
 333		v_next = v_lli->v_lli_next;
 334		p_next = v_lli->p_lli_next;
 335
 336		dma_pool_free(sdev->pool, v_lli, p_lli);
 337
 338		v_lli = v_next;
 339		p_lli = p_next;
 340	}
 341
 342	kfree(txd);
 343}
 344
 345static int sun6i_dma_start_desc(struct sun6i_vchan *vchan)
 346{
 347	struct sun6i_dma_dev *sdev = to_sun6i_dma_dev(vchan->vc.chan.device);
 348	struct virt_dma_desc *desc = vchan_next_desc(&vchan->vc);
 349	struct sun6i_pchan *pchan = vchan->phy;
 350	u32 irq_val, irq_reg, irq_offset;
 351
 352	if (!pchan)
 353		return -EAGAIN;
 354
 355	if (!desc) {
 356		pchan->desc = NULL;
 357		pchan->done = NULL;
 358		return -EAGAIN;
 359	}
 360
 361	list_del(&desc->node);
 362
 363	pchan->desc = to_sun6i_desc(&desc->tx);
 364	pchan->done = NULL;
 365
 366	sun6i_dma_dump_lli(vchan, pchan->desc->v_lli);
 367
 368	irq_reg = pchan->idx / DMA_IRQ_CHAN_NR;
 369	irq_offset = pchan->idx % DMA_IRQ_CHAN_NR;
 370
 371	vchan->irq_type = vchan->cyclic ? DMA_IRQ_PKG : DMA_IRQ_QUEUE;
 372
 373	irq_val = readl(sdev->base + DMA_IRQ_EN(irq_reg));
 374	irq_val &= ~((DMA_IRQ_HALF | DMA_IRQ_PKG | DMA_IRQ_QUEUE) <<
 375			(irq_offset * DMA_IRQ_CHAN_WIDTH));
 376	irq_val |= vchan->irq_type << (irq_offset * DMA_IRQ_CHAN_WIDTH);
 377	writel(irq_val, sdev->base + DMA_IRQ_EN(irq_reg));
 378
 379	writel(pchan->desc->p_lli, pchan->base + DMA_CHAN_LLI_ADDR);
 380	writel(DMA_CHAN_ENABLE_START, pchan->base + DMA_CHAN_ENABLE);
 381
 382	sun6i_dma_dump_com_regs(sdev);
 383	sun6i_dma_dump_chan_regs(sdev, pchan);
 384
 385	return 0;
 386}
 387
 388static void sun6i_dma_tasklet(unsigned long data)
 389{
 390	struct sun6i_dma_dev *sdev = (struct sun6i_dma_dev *)data;
 391	const struct sun6i_dma_config *cfg = sdev->cfg;
 392	struct sun6i_vchan *vchan;
 393	struct sun6i_pchan *pchan;
 394	unsigned int pchan_alloc = 0;
 395	unsigned int pchan_idx;
 396
 397	list_for_each_entry(vchan, &sdev->slave.channels, vc.chan.device_node) {
 398		spin_lock_irq(&vchan->vc.lock);
 399
 400		pchan = vchan->phy;
 401
 402		if (pchan && pchan->done) {
 403			if (sun6i_dma_start_desc(vchan)) {
 404				/*
 405				 * No current txd associated with this channel
 406				 */
 407				dev_dbg(sdev->slave.dev, "pchan %u: free\n",
 408					pchan->idx);
 409
 410				/* Mark this channel free */
 411				vchan->phy = NULL;
 412				pchan->vchan = NULL;
 413			}
 414		}
 415		spin_unlock_irq(&vchan->vc.lock);
 416	}
 417
 418	spin_lock_irq(&sdev->lock);
 419	for (pchan_idx = 0; pchan_idx < cfg->nr_max_channels; pchan_idx++) {
 420		pchan = &sdev->pchans[pchan_idx];
 421
 422		if (pchan->vchan || list_empty(&sdev->pending))
 423			continue;
 424
 425		vchan = list_first_entry(&sdev->pending,
 426					 struct sun6i_vchan, node);
 427
 428		/* Remove from pending channels */
 429		list_del_init(&vchan->node);
 430		pchan_alloc |= BIT(pchan_idx);
 431
 432		/* Mark this channel allocated */
 433		pchan->vchan = vchan;
 434		vchan->phy = pchan;
 435		dev_dbg(sdev->slave.dev, "pchan %u: alloc vchan %p\n",
 436			pchan->idx, &vchan->vc);
 437	}
 438	spin_unlock_irq(&sdev->lock);
 439
 440	for (pchan_idx = 0; pchan_idx < cfg->nr_max_channels; pchan_idx++) {
 441		if (!(pchan_alloc & BIT(pchan_idx)))
 442			continue;
 443
 444		pchan = sdev->pchans + pchan_idx;
 445		vchan = pchan->vchan;
 446		if (vchan) {
 447			spin_lock_irq(&vchan->vc.lock);
 448			sun6i_dma_start_desc(vchan);
 449			spin_unlock_irq(&vchan->vc.lock);
 450		}
 451	}
 452}
 453
 454static irqreturn_t sun6i_dma_interrupt(int irq, void *dev_id)
 455{
 456	struct sun6i_dma_dev *sdev = dev_id;
 457	struct sun6i_vchan *vchan;
 458	struct sun6i_pchan *pchan;
 459	int i, j, ret = IRQ_NONE;
 460	u32 status;
 461
 462	for (i = 0; i < sdev->cfg->nr_max_channels / DMA_IRQ_CHAN_NR; i++) {
 463		status = readl(sdev->base + DMA_IRQ_STAT(i));
 464		if (!status)
 465			continue;
 466
 467		dev_dbg(sdev->slave.dev, "DMA irq status %s: 0x%x\n",
 468			i ? "high" : "low", status);
 469
 470		writel(status, sdev->base + DMA_IRQ_STAT(i));
 471
 472		for (j = 0; (j < DMA_IRQ_CHAN_NR) && status; j++) {
 473			pchan = sdev->pchans + j;
 474			vchan = pchan->vchan;
 475			if (vchan && (status & vchan->irq_type)) {
 476				if (vchan->cyclic) {
 477					vchan_cyclic_callback(&pchan->desc->vd);
 478				} else {
 479					spin_lock(&vchan->vc.lock);
 480					vchan_cookie_complete(&pchan->desc->vd);
 481					pchan->done = pchan->desc;
 482					spin_unlock(&vchan->vc.lock);
 483				}
 484			}
 485
 486			status = status >> DMA_IRQ_CHAN_WIDTH;
 487		}
 488
 489		if (!atomic_read(&sdev->tasklet_shutdown))
 490			tasklet_schedule(&sdev->task);
 491		ret = IRQ_HANDLED;
 492	}
 493
 494	return ret;
 495}
 496
 497static int set_config(struct sun6i_dma_dev *sdev,
 498			struct dma_slave_config *sconfig,
 499			enum dma_transfer_direction direction,
 500			u32 *p_cfg)
 501{
 502	s8 src_width, dst_width, src_burst, dst_burst;
 503
 504	switch (direction) {
 505	case DMA_MEM_TO_DEV:
 506		src_burst = convert_burst(sconfig->src_maxburst ?
 507					sconfig->src_maxburst : 8);
 508		src_width = convert_buswidth(sconfig->src_addr_width !=
 509						DMA_SLAVE_BUSWIDTH_UNDEFINED ?
 510				sconfig->src_addr_width :
 511				DMA_SLAVE_BUSWIDTH_4_BYTES);
 512		dst_burst = convert_burst(sconfig->dst_maxburst);
 513		dst_width = convert_buswidth(sconfig->dst_addr_width);
 514		break;
 515	case DMA_DEV_TO_MEM:
 516		src_burst = convert_burst(sconfig->src_maxburst);
 517		src_width = convert_buswidth(sconfig->src_addr_width);
 518		dst_burst = convert_burst(sconfig->dst_maxburst ?
 519					sconfig->dst_maxburst : 8);
 520		dst_width = convert_buswidth(sconfig->dst_addr_width !=
 521						DMA_SLAVE_BUSWIDTH_UNDEFINED ?
 522				sconfig->dst_addr_width :
 523				DMA_SLAVE_BUSWIDTH_4_BYTES);
 524		break;
 525	default:
 526		return -EINVAL;
 527	}
 528
 529	if (src_burst < 0)
 530		return src_burst;
 531	if (src_width < 0)
 532		return src_width;
 533	if (dst_burst < 0)
 534		return dst_burst;
 535	if (dst_width < 0)
 536		return dst_width;
 537
 538	*p_cfg = DMA_CHAN_CFG_SRC_BURST(src_burst) |
 539		DMA_CHAN_CFG_SRC_WIDTH(src_width) |
 540		DMA_CHAN_CFG_DST_BURST(dst_burst) |
 541		DMA_CHAN_CFG_DST_WIDTH(dst_width);
 542
 543	return 0;
 544}
 545
 546static struct dma_async_tx_descriptor *sun6i_dma_prep_dma_memcpy(
 547		struct dma_chan *chan, dma_addr_t dest, dma_addr_t src,
 548		size_t len, unsigned long flags)
 549{
 550	struct sun6i_dma_dev *sdev = to_sun6i_dma_dev(chan->device);
 551	struct sun6i_vchan *vchan = to_sun6i_vchan(chan);
 552	struct sun6i_dma_lli *v_lli;
 553	struct sun6i_desc *txd;
 554	dma_addr_t p_lli;
 555	s8 burst, width;
 556
 557	dev_dbg(chan2dev(chan),
 558		"%s; chan: %d, dest: %pad, src: %pad, len: %zu. flags: 0x%08lx\n",
 559		__func__, vchan->vc.chan.chan_id, &dest, &src, len, flags);
 560
 561	if (!len)
 562		return NULL;
 563
 564	txd = kzalloc(sizeof(*txd), GFP_NOWAIT);
 565	if (!txd)
 566		return NULL;
 567
 568	v_lli = dma_pool_alloc(sdev->pool, GFP_NOWAIT, &p_lli);
 569	if (!v_lli) {
 570		dev_err(sdev->slave.dev, "Failed to alloc lli memory\n");
 571		goto err_txd_free;
 572	}
 573
 574	v_lli->src = src;
 575	v_lli->dst = dest;
 576	v_lli->len = len;
 577	v_lli->para = NORMAL_WAIT;
 578
 579	burst = convert_burst(8);
 580	width = convert_buswidth(DMA_SLAVE_BUSWIDTH_4_BYTES);
 581	v_lli->cfg = DMA_CHAN_CFG_SRC_DRQ(DRQ_SDRAM) |
 582		DMA_CHAN_CFG_DST_DRQ(DRQ_SDRAM) |
 583		DMA_CHAN_CFG_DST_LINEAR_MODE |
 584		DMA_CHAN_CFG_SRC_LINEAR_MODE |
 585		DMA_CHAN_CFG_SRC_BURST(burst) |
 586		DMA_CHAN_CFG_SRC_WIDTH(width) |
 587		DMA_CHAN_CFG_DST_BURST(burst) |
 588		DMA_CHAN_CFG_DST_WIDTH(width);
 589
 590	sun6i_dma_lli_add(NULL, v_lli, p_lli, txd);
 591
 592	sun6i_dma_dump_lli(vchan, v_lli);
 593
 594	return vchan_tx_prep(&vchan->vc, &txd->vd, flags);
 595
 596err_txd_free:
 597	kfree(txd);
 598	return NULL;
 599}
 600
 601static struct dma_async_tx_descriptor *sun6i_dma_prep_slave_sg(
 602		struct dma_chan *chan, struct scatterlist *sgl,
 603		unsigned int sg_len, enum dma_transfer_direction dir,
 604		unsigned long flags, void *context)
 605{
 606	struct sun6i_dma_dev *sdev = to_sun6i_dma_dev(chan->device);
 607	struct sun6i_vchan *vchan = to_sun6i_vchan(chan);
 608	struct dma_slave_config *sconfig = &vchan->cfg;
 609	struct sun6i_dma_lli *v_lli, *prev = NULL;
 610	struct sun6i_desc *txd;
 611	struct scatterlist *sg;
 612	dma_addr_t p_lli;
 613	u32 lli_cfg;
 614	int i, ret;
 615
 616	if (!sgl)
 617		return NULL;
 618
 619	ret = set_config(sdev, sconfig, dir, &lli_cfg);
 620	if (ret) {
 621		dev_err(chan2dev(chan), "Invalid DMA configuration\n");
 622		return NULL;
 623	}
 624
 625	txd = kzalloc(sizeof(*txd), GFP_NOWAIT);
 626	if (!txd)
 627		return NULL;
 628
 629	for_each_sg(sgl, sg, sg_len, i) {
 630		v_lli = dma_pool_alloc(sdev->pool, GFP_NOWAIT, &p_lli);
 631		if (!v_lli)
 632			goto err_lli_free;
 633
 634		v_lli->len = sg_dma_len(sg);
 635		v_lli->para = NORMAL_WAIT;
 636
 637		if (dir == DMA_MEM_TO_DEV) {
 638			v_lli->src = sg_dma_address(sg);
 639			v_lli->dst = sconfig->dst_addr;
 640			v_lli->cfg = lli_cfg |
 641				DMA_CHAN_CFG_DST_IO_MODE |
 642				DMA_CHAN_CFG_SRC_LINEAR_MODE |
 643				DMA_CHAN_CFG_SRC_DRQ(DRQ_SDRAM) |
 644				DMA_CHAN_CFG_DST_DRQ(vchan->port);
 645
 646			dev_dbg(chan2dev(chan),
 647				"%s; chan: %d, dest: %pad, src: %pad, len: %u. flags: 0x%08lx\n",
 648				__func__, vchan->vc.chan.chan_id,
 649				&sconfig->dst_addr, &sg_dma_address(sg),
 650				sg_dma_len(sg), flags);
 651
 652		} else {
 653			v_lli->src = sconfig->src_addr;
 654			v_lli->dst = sg_dma_address(sg);
 655			v_lli->cfg = lli_cfg |
 656				DMA_CHAN_CFG_DST_LINEAR_MODE |
 657				DMA_CHAN_CFG_SRC_IO_MODE |
 658				DMA_CHAN_CFG_DST_DRQ(DRQ_SDRAM) |
 659				DMA_CHAN_CFG_SRC_DRQ(vchan->port);
 660
 661			dev_dbg(chan2dev(chan),
 662				"%s; chan: %d, dest: %pad, src: %pad, len: %u. flags: 0x%08lx\n",
 663				__func__, vchan->vc.chan.chan_id,
 664				&sg_dma_address(sg), &sconfig->src_addr,
 665				sg_dma_len(sg), flags);
 666		}
 667
 668		prev = sun6i_dma_lli_add(prev, v_lli, p_lli, txd);
 669	}
 670
 671	dev_dbg(chan2dev(chan), "First: %pad\n", &txd->p_lli);
 672	for (prev = txd->v_lli; prev; prev = prev->v_lli_next)
 673		sun6i_dma_dump_lli(vchan, prev);
 674
 675	return vchan_tx_prep(&vchan->vc, &txd->vd, flags);
 676
 677err_lli_free:
 678	for (prev = txd->v_lli; prev; prev = prev->v_lli_next)
 679		dma_pool_free(sdev->pool, prev, virt_to_phys(prev));
 680	kfree(txd);
 681	return NULL;
 682}
 683
 684static struct dma_async_tx_descriptor *sun6i_dma_prep_dma_cyclic(
 685					struct dma_chan *chan,
 686					dma_addr_t buf_addr,
 687					size_t buf_len,
 688					size_t period_len,
 689					enum dma_transfer_direction dir,
 690					unsigned long flags)
 691{
 692	struct sun6i_dma_dev *sdev = to_sun6i_dma_dev(chan->device);
 693	struct sun6i_vchan *vchan = to_sun6i_vchan(chan);
 694	struct dma_slave_config *sconfig = &vchan->cfg;
 695	struct sun6i_dma_lli *v_lli, *prev = NULL;
 696	struct sun6i_desc *txd;
 697	dma_addr_t p_lli;
 698	u32 lli_cfg;
 699	unsigned int i, periods = buf_len / period_len;
 700	int ret;
 701
 702	ret = set_config(sdev, sconfig, dir, &lli_cfg);
 703	if (ret) {
 704		dev_err(chan2dev(chan), "Invalid DMA configuration\n");
 705		return NULL;
 706	}
 707
 708	txd = kzalloc(sizeof(*txd), GFP_NOWAIT);
 709	if (!txd)
 710		return NULL;
 711
 712	for (i = 0; i < periods; i++) {
 713		v_lli = dma_pool_alloc(sdev->pool, GFP_NOWAIT, &p_lli);
 714		if (!v_lli) {
 715			dev_err(sdev->slave.dev, "Failed to alloc lli memory\n");
 716			goto err_lli_free;
 717		}
 718
 719		v_lli->len = period_len;
 720		v_lli->para = NORMAL_WAIT;
 721
 722		if (dir == DMA_MEM_TO_DEV) {
 723			v_lli->src = buf_addr + period_len * i;
 724			v_lli->dst = sconfig->dst_addr;
 725			v_lli->cfg = lli_cfg |
 726				DMA_CHAN_CFG_DST_IO_MODE |
 727				DMA_CHAN_CFG_SRC_LINEAR_MODE |
 728				DMA_CHAN_CFG_SRC_DRQ(DRQ_SDRAM) |
 729				DMA_CHAN_CFG_DST_DRQ(vchan->port);
 730		} else {
 731			v_lli->src = sconfig->src_addr;
 732			v_lli->dst = buf_addr + period_len * i;
 733			v_lli->cfg = lli_cfg |
 734				DMA_CHAN_CFG_DST_LINEAR_MODE |
 735				DMA_CHAN_CFG_SRC_IO_MODE |
 736				DMA_CHAN_CFG_DST_DRQ(DRQ_SDRAM) |
 737				DMA_CHAN_CFG_SRC_DRQ(vchan->port);
 738		}
 739
 740		prev = sun6i_dma_lli_add(prev, v_lli, p_lli, txd);
 741	}
 742
 743	prev->p_lli_next = txd->p_lli;		/* cyclic list */
 744
 745	vchan->cyclic = true;
 746
 747	return vchan_tx_prep(&vchan->vc, &txd->vd, flags);
 748
 749err_lli_free:
 750	for (prev = txd->v_lli; prev; prev = prev->v_lli_next)
 751		dma_pool_free(sdev->pool, prev, virt_to_phys(prev));
 752	kfree(txd);
 753	return NULL;
 754}
 755
 756static int sun6i_dma_config(struct dma_chan *chan,
 757			    struct dma_slave_config *config)
 758{
 759	struct sun6i_vchan *vchan = to_sun6i_vchan(chan);
 760
 761	memcpy(&vchan->cfg, config, sizeof(*config));
 762
 763	return 0;
 764}
 765
 766static int sun6i_dma_pause(struct dma_chan *chan)
 767{
 768	struct sun6i_dma_dev *sdev = to_sun6i_dma_dev(chan->device);
 769	struct sun6i_vchan *vchan = to_sun6i_vchan(chan);
 770	struct sun6i_pchan *pchan = vchan->phy;
 771
 772	dev_dbg(chan2dev(chan), "vchan %p: pause\n", &vchan->vc);
 773
 774	if (pchan) {
 775		writel(DMA_CHAN_PAUSE_PAUSE,
 776		       pchan->base + DMA_CHAN_PAUSE);
 777	} else {
 778		spin_lock(&sdev->lock);
 779		list_del_init(&vchan->node);
 780		spin_unlock(&sdev->lock);
 781	}
 782
 783	return 0;
 784}
 785
 786static int sun6i_dma_resume(struct dma_chan *chan)
 787{
 788	struct sun6i_dma_dev *sdev = to_sun6i_dma_dev(chan->device);
 789	struct sun6i_vchan *vchan = to_sun6i_vchan(chan);
 790	struct sun6i_pchan *pchan = vchan->phy;
 791	unsigned long flags;
 792
 793	dev_dbg(chan2dev(chan), "vchan %p: resume\n", &vchan->vc);
 794
 795	spin_lock_irqsave(&vchan->vc.lock, flags);
 796
 797	if (pchan) {
 798		writel(DMA_CHAN_PAUSE_RESUME,
 799		       pchan->base + DMA_CHAN_PAUSE);
 800	} else if (!list_empty(&vchan->vc.desc_issued)) {
 801		spin_lock(&sdev->lock);
 802		list_add_tail(&vchan->node, &sdev->pending);
 803		spin_unlock(&sdev->lock);
 804	}
 805
 806	spin_unlock_irqrestore(&vchan->vc.lock, flags);
 807
 808	return 0;
 809}
 810
 811static int sun6i_dma_terminate_all(struct dma_chan *chan)
 812{
 813	struct sun6i_dma_dev *sdev = to_sun6i_dma_dev(chan->device);
 814	struct sun6i_vchan *vchan = to_sun6i_vchan(chan);
 815	struct sun6i_pchan *pchan = vchan->phy;
 816	unsigned long flags;
 817	LIST_HEAD(head);
 818
 819	spin_lock(&sdev->lock);
 820	list_del_init(&vchan->node);
 821	spin_unlock(&sdev->lock);
 822
 823	spin_lock_irqsave(&vchan->vc.lock, flags);
 824
 825	if (vchan->cyclic) {
 826		vchan->cyclic = false;
 827		if (pchan && pchan->desc) {
 828			struct virt_dma_desc *vd = &pchan->desc->vd;
 829			struct virt_dma_chan *vc = &vchan->vc;
 830
 831			list_add_tail(&vd->node, &vc->desc_completed);
 832		}
 833	}
 834
 835	vchan_get_all_descriptors(&vchan->vc, &head);
 836
 837	if (pchan) {
 838		writel(DMA_CHAN_ENABLE_STOP, pchan->base + DMA_CHAN_ENABLE);
 839		writel(DMA_CHAN_PAUSE_RESUME, pchan->base + DMA_CHAN_PAUSE);
 840
 841		vchan->phy = NULL;
 842		pchan->vchan = NULL;
 843		pchan->desc = NULL;
 844		pchan->done = NULL;
 845	}
 846
 847	spin_unlock_irqrestore(&vchan->vc.lock, flags);
 848
 849	vchan_dma_desc_free_list(&vchan->vc, &head);
 850
 851	return 0;
 852}
 853
 854static enum dma_status sun6i_dma_tx_status(struct dma_chan *chan,
 855					   dma_cookie_t cookie,
 856					   struct dma_tx_state *state)
 857{
 858	struct sun6i_vchan *vchan = to_sun6i_vchan(chan);
 859	struct sun6i_pchan *pchan = vchan->phy;
 860	struct sun6i_dma_lli *lli;
 861	struct virt_dma_desc *vd;
 862	struct sun6i_desc *txd;
 863	enum dma_status ret;
 864	unsigned long flags;
 865	size_t bytes = 0;
 866
 867	ret = dma_cookie_status(chan, cookie, state);
 868	if (ret == DMA_COMPLETE || !state)
 869		return ret;
 870
 871	spin_lock_irqsave(&vchan->vc.lock, flags);
 872
 873	vd = vchan_find_desc(&vchan->vc, cookie);
 874	txd = to_sun6i_desc(&vd->tx);
 875
 876	if (vd) {
 877		for (lli = txd->v_lli; lli != NULL; lli = lli->v_lli_next)
 878			bytes += lli->len;
 879	} else if (!pchan || !pchan->desc) {
 880		bytes = 0;
 881	} else {
 882		bytes = sun6i_get_chan_size(pchan);
 883	}
 884
 885	spin_unlock_irqrestore(&vchan->vc.lock, flags);
 886
 887	dma_set_residue(state, bytes);
 888
 889	return ret;
 890}
 891
 892static void sun6i_dma_issue_pending(struct dma_chan *chan)
 893{
 894	struct sun6i_dma_dev *sdev = to_sun6i_dma_dev(chan->device);
 895	struct sun6i_vchan *vchan = to_sun6i_vchan(chan);
 896	unsigned long flags;
 897
 898	spin_lock_irqsave(&vchan->vc.lock, flags);
 899
 900	if (vchan_issue_pending(&vchan->vc)) {
 901		spin_lock(&sdev->lock);
 902
 903		if (!vchan->phy && list_empty(&vchan->node)) {
 904			list_add_tail(&vchan->node, &sdev->pending);
 905			tasklet_schedule(&sdev->task);
 906			dev_dbg(chan2dev(chan), "vchan %p: issued\n",
 907				&vchan->vc);
 908		}
 909
 910		spin_unlock(&sdev->lock);
 911	} else {
 912		dev_dbg(chan2dev(chan), "vchan %p: nothing to issue\n",
 913			&vchan->vc);
 914	}
 915
 916	spin_unlock_irqrestore(&vchan->vc.lock, flags);
 917}
 918
 919static void sun6i_dma_free_chan_resources(struct dma_chan *chan)
 920{
 921	struct sun6i_dma_dev *sdev = to_sun6i_dma_dev(chan->device);
 922	struct sun6i_vchan *vchan = to_sun6i_vchan(chan);
 923	unsigned long flags;
 924
 925	spin_lock_irqsave(&sdev->lock, flags);
 926	list_del_init(&vchan->node);
 927	spin_unlock_irqrestore(&sdev->lock, flags);
 928
 929	vchan_free_chan_resources(&vchan->vc);
 930}
 931
 932static struct dma_chan *sun6i_dma_of_xlate(struct of_phandle_args *dma_spec,
 933					   struct of_dma *ofdma)
 934{
 935	struct sun6i_dma_dev *sdev = ofdma->of_dma_data;
 936	struct sun6i_vchan *vchan;
 937	struct dma_chan *chan;
 938	u8 port = dma_spec->args[0];
 939
 940	if (port > sdev->cfg->nr_max_requests)
 941		return NULL;
 942
 943	chan = dma_get_any_slave_channel(&sdev->slave);
 944	if (!chan)
 945		return NULL;
 946
 947	vchan = to_sun6i_vchan(chan);
 948	vchan->port = port;
 949
 950	return chan;
 951}
 952
 953static inline void sun6i_kill_tasklet(struct sun6i_dma_dev *sdev)
 954{
 955	/* Disable all interrupts from DMA */
 956	writel(0, sdev->base + DMA_IRQ_EN(0));
 957	writel(0, sdev->base + DMA_IRQ_EN(1));
 958
 959	/* Prevent spurious interrupts from scheduling the tasklet */
 960	atomic_inc(&sdev->tasklet_shutdown);
 961
 962	/* Make sure we won't have any further interrupts */
 963	devm_free_irq(sdev->slave.dev, sdev->irq, sdev);
 964
 965	/* Actually prevent the tasklet from being scheduled */
 966	tasklet_kill(&sdev->task);
 967}
 968
 969static inline void sun6i_dma_free(struct sun6i_dma_dev *sdev)
 970{
 971	int i;
 972
 973	for (i = 0; i < sdev->cfg->nr_max_vchans; i++) {
 974		struct sun6i_vchan *vchan = &sdev->vchans[i];
 975
 976		list_del(&vchan->vc.chan.device_node);
 977		tasklet_kill(&vchan->vc.task);
 978	}
 979}
 980
 981/*
 982 * For A31:
 983 *
 984 * There's 16 physical channels that can work in parallel.
 985 *
 986 * However we have 30 different endpoints for our requests.
 987 *
 988 * Since the channels are able to handle only an unidirectional
 989 * transfer, we need to allocate more virtual channels so that
 990 * everyone can grab one channel.
 991 *
 992 * Some devices can't work in both direction (mostly because it
 993 * wouldn't make sense), so we have a bit fewer virtual channels than
 994 * 2 channels per endpoints.
 995 */
 996
 997static struct sun6i_dma_config sun6i_a31_dma_cfg = {
 998	.nr_max_channels = 16,
 999	.nr_max_requests = 30,
1000	.nr_max_vchans   = 53,
1001};
1002
1003/*
1004 * The A23 only has 8 physical channels, a maximum DRQ port id of 24,
1005 * and a total of 37 usable source and destination endpoints.
1006 */
1007
1008static struct sun6i_dma_config sun8i_a23_dma_cfg = {
1009	.nr_max_channels = 8,
1010	.nr_max_requests = 24,
1011	.nr_max_vchans   = 37,
1012};
1013
1014static struct sun6i_dma_config sun8i_a83t_dma_cfg = {
1015	.nr_max_channels = 8,
1016	.nr_max_requests = 28,
1017	.nr_max_vchans   = 39,
1018};
1019
1020/*
1021 * The H3 has 12 physical channels, a maximum DRQ port id of 27,
1022 * and a total of 34 usable source and destination endpoints.
1023 */
1024
1025static struct sun6i_dma_config sun8i_h3_dma_cfg = {
1026	.nr_max_channels = 12,
1027	.nr_max_requests = 27,
1028	.nr_max_vchans   = 34,
1029};
1030
1031static const struct of_device_id sun6i_dma_match[] = {
1032	{ .compatible = "allwinner,sun6i-a31-dma", .data = &sun6i_a31_dma_cfg },
1033	{ .compatible = "allwinner,sun8i-a23-dma", .data = &sun8i_a23_dma_cfg },
1034	{ .compatible = "allwinner,sun8i-a83t-dma", .data = &sun8i_a83t_dma_cfg },
1035	{ .compatible = "allwinner,sun8i-h3-dma", .data = &sun8i_h3_dma_cfg },
1036	{ /* sentinel */ }
1037};
1038MODULE_DEVICE_TABLE(of, sun6i_dma_match);
1039
1040static int sun6i_dma_probe(struct platform_device *pdev)
1041{
1042	const struct of_device_id *device;
1043	struct sun6i_dma_dev *sdc;
1044	struct resource *res;
1045	int ret, i;
1046
1047	sdc = devm_kzalloc(&pdev->dev, sizeof(*sdc), GFP_KERNEL);
1048	if (!sdc)
1049		return -ENOMEM;
1050
1051	device = of_match_device(sun6i_dma_match, &pdev->dev);
1052	if (!device)
1053		return -ENODEV;
1054	sdc->cfg = device->data;
1055
1056	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1057	sdc->base = devm_ioremap_resource(&pdev->dev, res);
1058	if (IS_ERR(sdc->base))
1059		return PTR_ERR(sdc->base);
1060
1061	sdc->irq = platform_get_irq(pdev, 0);
1062	if (sdc->irq < 0) {
1063		dev_err(&pdev->dev, "Cannot claim IRQ\n");
1064		return sdc->irq;
1065	}
1066
1067	sdc->clk = devm_clk_get(&pdev->dev, NULL);
1068	if (IS_ERR(sdc->clk)) {
1069		dev_err(&pdev->dev, "No clock specified\n");
1070		return PTR_ERR(sdc->clk);
1071	}
1072
1073	sdc->rstc = devm_reset_control_get(&pdev->dev, NULL);
1074	if (IS_ERR(sdc->rstc)) {
1075		dev_err(&pdev->dev, "No reset controller specified\n");
1076		return PTR_ERR(sdc->rstc);
1077	}
1078
1079	sdc->pool = dmam_pool_create(dev_name(&pdev->dev), &pdev->dev,
1080				     sizeof(struct sun6i_dma_lli), 4, 0);
1081	if (!sdc->pool) {
1082		dev_err(&pdev->dev, "No memory for descriptors dma pool\n");
1083		return -ENOMEM;
1084	}
1085
1086	platform_set_drvdata(pdev, sdc);
1087	INIT_LIST_HEAD(&sdc->pending);
1088	spin_lock_init(&sdc->lock);
1089
1090	dma_cap_set(DMA_PRIVATE, sdc->slave.cap_mask);
1091	dma_cap_set(DMA_MEMCPY, sdc->slave.cap_mask);
1092	dma_cap_set(DMA_SLAVE, sdc->slave.cap_mask);
1093	dma_cap_set(DMA_CYCLIC, sdc->slave.cap_mask);
1094
1095	INIT_LIST_HEAD(&sdc->slave.channels);
1096	sdc->slave.device_free_chan_resources	= sun6i_dma_free_chan_resources;
1097	sdc->slave.device_tx_status		= sun6i_dma_tx_status;
1098	sdc->slave.device_issue_pending		= sun6i_dma_issue_pending;
1099	sdc->slave.device_prep_slave_sg		= sun6i_dma_prep_slave_sg;
1100	sdc->slave.device_prep_dma_memcpy	= sun6i_dma_prep_dma_memcpy;
1101	sdc->slave.device_prep_dma_cyclic	= sun6i_dma_prep_dma_cyclic;
1102	sdc->slave.copy_align			= DMAENGINE_ALIGN_4_BYTES;
1103	sdc->slave.device_config		= sun6i_dma_config;
1104	sdc->slave.device_pause			= sun6i_dma_pause;
1105	sdc->slave.device_resume		= sun6i_dma_resume;
1106	sdc->slave.device_terminate_all		= sun6i_dma_terminate_all;
1107	sdc->slave.src_addr_widths		= BIT(DMA_SLAVE_BUSWIDTH_1_BYTE) |
1108						  BIT(DMA_SLAVE_BUSWIDTH_2_BYTES) |
1109						  BIT(DMA_SLAVE_BUSWIDTH_4_BYTES);
1110	sdc->slave.dst_addr_widths		= BIT(DMA_SLAVE_BUSWIDTH_1_BYTE) |
1111						  BIT(DMA_SLAVE_BUSWIDTH_2_BYTES) |
1112						  BIT(DMA_SLAVE_BUSWIDTH_4_BYTES);
1113	sdc->slave.directions			= BIT(DMA_DEV_TO_MEM) |
1114						  BIT(DMA_MEM_TO_DEV);
1115	sdc->slave.residue_granularity		= DMA_RESIDUE_GRANULARITY_BURST;
1116	sdc->slave.dev = &pdev->dev;
1117
1118	sdc->pchans = devm_kcalloc(&pdev->dev, sdc->cfg->nr_max_channels,
1119				   sizeof(struct sun6i_pchan), GFP_KERNEL);
1120	if (!sdc->pchans)
1121		return -ENOMEM;
1122
1123	sdc->vchans = devm_kcalloc(&pdev->dev, sdc->cfg->nr_max_vchans,
1124				   sizeof(struct sun6i_vchan), GFP_KERNEL);
1125	if (!sdc->vchans)
1126		return -ENOMEM;
1127
1128	tasklet_init(&sdc->task, sun6i_dma_tasklet, (unsigned long)sdc);
1129
1130	for (i = 0; i < sdc->cfg->nr_max_channels; i++) {
1131		struct sun6i_pchan *pchan = &sdc->pchans[i];
1132
1133		pchan->idx = i;
1134		pchan->base = sdc->base + 0x100 + i * 0x40;
1135	}
1136
1137	for (i = 0; i < sdc->cfg->nr_max_vchans; i++) {
1138		struct sun6i_vchan *vchan = &sdc->vchans[i];
1139
1140		INIT_LIST_HEAD(&vchan->node);
1141		vchan->vc.desc_free = sun6i_dma_free_desc;
1142		vchan_init(&vchan->vc, &sdc->slave);
1143	}
1144
1145	ret = reset_control_deassert(sdc->rstc);
1146	if (ret) {
1147		dev_err(&pdev->dev, "Couldn't deassert the device from reset\n");
1148		goto err_chan_free;
1149	}
1150
1151	ret = clk_prepare_enable(sdc->clk);
1152	if (ret) {
1153		dev_err(&pdev->dev, "Couldn't enable the clock\n");
1154		goto err_reset_assert;
1155	}
1156
1157	ret = devm_request_irq(&pdev->dev, sdc->irq, sun6i_dma_interrupt, 0,
1158			       dev_name(&pdev->dev), sdc);
1159	if (ret) {
1160		dev_err(&pdev->dev, "Cannot request IRQ\n");
1161		goto err_clk_disable;
1162	}
1163
1164	ret = dma_async_device_register(&sdc->slave);
1165	if (ret) {
1166		dev_warn(&pdev->dev, "Failed to register DMA engine device\n");
1167		goto err_irq_disable;
1168	}
1169
1170	ret = of_dma_controller_register(pdev->dev.of_node, sun6i_dma_of_xlate,
1171					 sdc);
1172	if (ret) {
1173		dev_err(&pdev->dev, "of_dma_controller_register failed\n");
1174		goto err_dma_unregister;
1175	}
1176
1177	/*
1178	 * sun8i variant requires us to toggle a dma gating register,
1179	 * as seen in Allwinner's SDK. This register is not documented
1180	 * in the A23 user manual.
1181	 */
1182	if (of_device_is_compatible(pdev->dev.of_node,
1183				    "allwinner,sun8i-a23-dma"))
1184		writel(SUN8I_DMA_GATE_ENABLE, sdc->base + SUN8I_DMA_GATE);
1185
1186	return 0;
1187
1188err_dma_unregister:
1189	dma_async_device_unregister(&sdc->slave);
1190err_irq_disable:
1191	sun6i_kill_tasklet(sdc);
1192err_clk_disable:
1193	clk_disable_unprepare(sdc->clk);
1194err_reset_assert:
1195	reset_control_assert(sdc->rstc);
1196err_chan_free:
1197	sun6i_dma_free(sdc);
1198	return ret;
1199}
1200
1201static int sun6i_dma_remove(struct platform_device *pdev)
1202{
1203	struct sun6i_dma_dev *sdc = platform_get_drvdata(pdev);
1204
1205	of_dma_controller_free(pdev->dev.of_node);
1206	dma_async_device_unregister(&sdc->slave);
1207
1208	sun6i_kill_tasklet(sdc);
1209
1210	clk_disable_unprepare(sdc->clk);
1211	reset_control_assert(sdc->rstc);
1212
1213	sun6i_dma_free(sdc);
1214
1215	return 0;
1216}
1217
1218static struct platform_driver sun6i_dma_driver = {
1219	.probe		= sun6i_dma_probe,
1220	.remove		= sun6i_dma_remove,
1221	.driver = {
1222		.name		= "sun6i-dma",
1223		.of_match_table	= sun6i_dma_match,
1224	},
1225};
1226module_platform_driver(sun6i_dma_driver);
1227
1228MODULE_DESCRIPTION("Allwinner A31 DMA Controller Driver");
1229MODULE_AUTHOR("Sugar <shuge@allwinnertech.com>");
1230MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com>");
1231MODULE_LICENSE("GPL");