Adding upstream version 6.1.76.upstream/6.1.76

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 2052 insertions, 0 deletions

diff --git a/drivers/dma/sh/rcar-dmac.c b/drivers/dma/sh/rcar-dmac.c
new file mode 100644
index 000000000..641d689d1
--- /dev/null
+++ b/drivers/dma/sh/rcar-dmac.c
@@ -0,0 +1,2052 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Renesas R-Car Gen2/Gen3 DMA Controller Driver
+ *
+ * Copyright (C) 2014-2019 Renesas Electronics Inc.
+ *
+ * Author: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
+ */
+
+#include <linux/delay.h>
+#include <linux/dma-mapping.h>
+#include <linux/dmaengine.h>
+#include <linux/interrupt.h>
+#include <linux/list.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/of.h>
+#include <linux/of_dma.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+
+#include "../dmaengine.h"
+
+/*
+ * struct rcar_dmac_xfer_chunk - Descriptor for a hardware transfer
+ * @node: entry in the parent's chunks list
+ * @src_addr: device source address
+ * @dst_addr: device destination address
+ * @size: transfer size in bytes
+ */
+struct rcar_dmac_xfer_chunk {
+	struct list_head node;
+
+	dma_addr_t src_addr;
+	dma_addr_t dst_addr;
+	u32 size;
+};
+
+/*
+ * struct rcar_dmac_hw_desc - Hardware descriptor for a transfer chunk
+ * @sar: value of the SAR register (source address)
+ * @dar: value of the DAR register (destination address)
+ * @tcr: value of the TCR register (transfer count)
+ */
+struct rcar_dmac_hw_desc {
+	u32 sar;
+	u32 dar;
+	u32 tcr;
+	u32 reserved;
+} __attribute__((__packed__));
+
+/*
+ * struct rcar_dmac_desc - R-Car Gen2 DMA Transfer Descriptor
+ * @async_tx: base DMA asynchronous transaction descriptor
+ * @direction: direction of the DMA transfer
+ * @xfer_shift: log2 of the transfer size
+ * @chcr: value of the channel configuration register for this transfer
+ * @node: entry in the channel's descriptors lists
+ * @chunks: list of transfer chunks for this transfer
+ * @running: the transfer chunk being currently processed
+ * @nchunks: number of transfer chunks for this transfer
+ * @hwdescs.use: whether the transfer descriptor uses hardware descriptors
+ * @hwdescs.mem: hardware descriptors memory for the transfer
+ * @hwdescs.dma: device address of the hardware descriptors memory
+ * @hwdescs.size: size of the hardware descriptors in bytes
+ * @size: transfer size in bytes
+ * @cyclic: when set indicates that the DMA transfer is cyclic
+ */
+struct rcar_dmac_desc {
+	struct dma_async_tx_descriptor async_tx;
+	enum dma_transfer_direction direction;
+	unsigned int xfer_shift;
+	u32 chcr;
+
+	struct list_head node;
+	struct list_head chunks;
+	struct rcar_dmac_xfer_chunk *running;
+	unsigned int nchunks;
+
+	struct {
+		bool use;
+		struct rcar_dmac_hw_desc *mem;
+		dma_addr_t dma;
+		size_t size;
+	} hwdescs;
+
+	unsigned int size;
+	bool cyclic;
+};
+
+#define to_rcar_dmac_desc(d)	container_of(d, struct rcar_dmac_desc, async_tx)
+
+/*
+ * struct rcar_dmac_desc_page - One page worth of descriptors
+ * @node: entry in the channel's pages list
+ * @descs: array of DMA descriptors
+ * @chunks: array of transfer chunk descriptors
+ */
+struct rcar_dmac_desc_page {
+	struct list_head node;
+
+	union {
+		DECLARE_FLEX_ARRAY(struct rcar_dmac_desc, descs);
+		DECLARE_FLEX_ARRAY(struct rcar_dmac_xfer_chunk, chunks);
+	};
+};
+
+#define RCAR_DMAC_DESCS_PER_PAGE					\
+	((PAGE_SIZE - offsetof(struct rcar_dmac_desc_page, descs)) /	\
+	sizeof(struct rcar_dmac_desc))
+#define RCAR_DMAC_XFER_CHUNKS_PER_PAGE					\
+	((PAGE_SIZE - offsetof(struct rcar_dmac_desc_page, chunks)) /	\
+	sizeof(struct rcar_dmac_xfer_chunk))
+
+/*
+ * struct rcar_dmac_chan_slave - Slave configuration
+ * @slave_addr: slave memory address
+ * @xfer_size: size (in bytes) of hardware transfers
+ */
+struct rcar_dmac_chan_slave {
+	phys_addr_t slave_addr;
+	unsigned int xfer_size;
+};
+
+/*
+ * struct rcar_dmac_chan_map - Map of slave device phys to dma address
+ * @addr: slave dma address
+ * @dir: direction of mapping
+ * @slave: slave configuration that is mapped
+ */
+struct rcar_dmac_chan_map {
+	dma_addr_t addr;
+	enum dma_data_direction dir;
+	struct rcar_dmac_chan_slave slave;
+};
+
+/*
+ * struct rcar_dmac_chan - R-Car Gen2 DMA Controller Channel
+ * @chan: base DMA channel object
+ * @iomem: channel I/O memory base
+ * @index: index of this channel in the controller
+ * @irq: channel IRQ
+ * @src: slave memory address and size on the source side
+ * @dst: slave memory address and size on the destination side
+ * @mid_rid: hardware MID/RID for the DMA client using this channel
+ * @lock: protects the channel CHCR register and the desc members
+ * @desc.free: list of free descriptors
+ * @desc.pending: list of pending descriptors (submitted with tx_submit)
+ * @desc.active: list of active descriptors (activated with issue_pending)
+ * @desc.done: list of completed descriptors
+ * @desc.wait: list of descriptors waiting for an ack
+ * @desc.running: the descriptor being processed (a member of the active list)
+ * @desc.chunks_free: list of free transfer chunk descriptors
+ * @desc.pages: list of pages used by allocated descriptors
+ */
+struct rcar_dmac_chan {
+	struct dma_chan chan;
+	void __iomem *iomem;
+	unsigned int index;
+	int irq;
+
+	struct rcar_dmac_chan_slave src;
+	struct rcar_dmac_chan_slave dst;
+	struct rcar_dmac_chan_map map;
+	int mid_rid;
+
+	spinlock_t lock;
+
+	struct {
+		struct list_head free;
+		struct list_head pending;
+		struct list_head active;
+		struct list_head done;
+		struct list_head wait;
+		struct rcar_dmac_desc *running;
+
+		struct list_head chunks_free;
+
+		struct list_head pages;
+	} desc;
+};
+
+#define to_rcar_dmac_chan(c)	container_of(c, struct rcar_dmac_chan, chan)
+
+/*
+ * struct rcar_dmac - R-Car Gen2 DMA Controller
+ * @engine: base DMA engine object
+ * @dev: the hardware device
+ * @dmac_base: remapped base register block
+ * @chan_base: remapped channel register block (optional)
+ * @n_channels: number of available channels
+ * @channels: array of DMAC channels
+ * @channels_mask: bitfield of which DMA channels are managed by this driver
+ * @modules: bitmask of client modules in use
+ */
+struct rcar_dmac {
+	struct dma_device engine;
+	struct device *dev;
+	void __iomem *dmac_base;
+	void __iomem *chan_base;
+
+	unsigned int n_channels;
+	struct rcar_dmac_chan *channels;
+	u32 channels_mask;
+
+	DECLARE_BITMAP(modules, 256);
+};
+
+#define to_rcar_dmac(d)		container_of(d, struct rcar_dmac, engine)
+
+#define for_each_rcar_dmac_chan(i, dmac, chan)						\
+	for (i = 0, chan = &(dmac)->channels[0]; i < (dmac)->n_channels; i++, chan++)	\
+		if (!((dmac)->channels_mask & BIT(i))) continue; else
+
+/*
+ * struct rcar_dmac_of_data - This driver's OF data
+ * @chan_offset_base: DMAC channels base offset
+ * @chan_offset_stride: DMAC channels offset stride
+ */
+struct rcar_dmac_of_data {
+	u32 chan_offset_base;
+	u32 chan_offset_stride;
+};
+
+/* -----------------------------------------------------------------------------
+ * Registers
+ */
+
+#define RCAR_DMAISTA			0x0020
+#define RCAR_DMASEC			0x0030
+#define RCAR_DMAOR			0x0060
+#define RCAR_DMAOR_PRI_FIXED		(0 << 8)
+#define RCAR_DMAOR_PRI_ROUND_ROBIN	(3 << 8)
+#define RCAR_DMAOR_AE			(1 << 2)
+#define RCAR_DMAOR_DME			(1 << 0)
+#define RCAR_DMACHCLR			0x0080	/* Not on R-Car Gen4 */
+#define RCAR_DMADPSEC			0x00a0
+
+#define RCAR_DMASAR			0x0000
+#define RCAR_DMADAR			0x0004
+#define RCAR_DMATCR			0x0008
+#define RCAR_DMATCR_MASK		0x00ffffff
+#define RCAR_DMATSR			0x0028
+#define RCAR_DMACHCR			0x000c
+#define RCAR_DMACHCR_CAE		(1 << 31)
+#define RCAR_DMACHCR_CAIE		(1 << 30)
+#define RCAR_DMACHCR_DPM_DISABLED	(0 << 28)
+#define RCAR_DMACHCR_DPM_ENABLED	(1 << 28)
+#define RCAR_DMACHCR_DPM_REPEAT		(2 << 28)
+#define RCAR_DMACHCR_DPM_INFINITE	(3 << 28)
+#define RCAR_DMACHCR_RPT_SAR		(1 << 27)
+#define RCAR_DMACHCR_RPT_DAR		(1 << 26)
+#define RCAR_DMACHCR_RPT_TCR		(1 << 25)
+#define RCAR_DMACHCR_DPB		(1 << 22)
+#define RCAR_DMACHCR_DSE		(1 << 19)
+#define RCAR_DMACHCR_DSIE		(1 << 18)
+#define RCAR_DMACHCR_TS_1B		((0 << 20) | (0 << 3))
+#define RCAR_DMACHCR_TS_2B		((0 << 20) | (1 << 3))
+#define RCAR_DMACHCR_TS_4B		((0 << 20) | (2 << 3))
+#define RCAR_DMACHCR_TS_16B		((0 << 20) | (3 << 3))
+#define RCAR_DMACHCR_TS_32B		((1 << 20) | (0 << 3))
+#define RCAR_DMACHCR_TS_64B		((1 << 20) | (1 << 3))
+#define RCAR_DMACHCR_TS_8B		((1 << 20) | (3 << 3))
+#define RCAR_DMACHCR_DM_FIXED		(0 << 14)
+#define RCAR_DMACHCR_DM_INC		(1 << 14)
+#define RCAR_DMACHCR_DM_DEC		(2 << 14)
+#define RCAR_DMACHCR_SM_FIXED		(0 << 12)
+#define RCAR_DMACHCR_SM_INC		(1 << 12)
+#define RCAR_DMACHCR_SM_DEC		(2 << 12)
+#define RCAR_DMACHCR_RS_AUTO		(4 << 8)
+#define RCAR_DMACHCR_RS_DMARS		(8 << 8)
+#define RCAR_DMACHCR_IE			(1 << 2)
+#define RCAR_DMACHCR_TE			(1 << 1)
+#define RCAR_DMACHCR_DE			(1 << 0)
+#define RCAR_DMATCRB			0x0018
+#define RCAR_DMATSRB			0x0038
+#define RCAR_DMACHCRB			0x001c
+#define RCAR_DMACHCRB_DCNT(n)		((n) << 24)
+#define RCAR_DMACHCRB_DPTR_MASK		(0xff << 16)
+#define RCAR_DMACHCRB_DPTR_SHIFT	16
+#define RCAR_DMACHCRB_DRST		(1 << 15)
+#define RCAR_DMACHCRB_DTS		(1 << 8)
+#define RCAR_DMACHCRB_SLM_NORMAL	(0 << 4)
+#define RCAR_DMACHCRB_SLM_CLK(n)	((8 | (n)) << 4)
+#define RCAR_DMACHCRB_PRI(n)		((n) << 0)
+#define RCAR_DMARS			0x0040
+#define RCAR_DMABUFCR			0x0048
+#define RCAR_DMABUFCR_MBU(n)		((n) << 16)
+#define RCAR_DMABUFCR_ULB(n)		((n) << 0)
+#define RCAR_DMADPBASE			0x0050
+#define RCAR_DMADPBASE_MASK		0xfffffff0
+#define RCAR_DMADPBASE_SEL		(1 << 0)
+#define RCAR_DMADPCR			0x0054
+#define RCAR_DMADPCR_DIPT(n)		((n) << 24)
+#define RCAR_DMAFIXSAR			0x0010
+#define RCAR_DMAFIXDAR			0x0014
+#define RCAR_DMAFIXDPBASE		0x0060
+
+/* For R-Car Gen4 */
+#define RCAR_GEN4_DMACHCLR		0x0100
+
+/* Hardcode the MEMCPY transfer size to 4 bytes. */
+#define RCAR_DMAC_MEMCPY_XFER_SIZE	4
+
+/* -----------------------------------------------------------------------------
+ * Device access
+ */
+
+static void rcar_dmac_write(struct rcar_dmac *dmac, u32 reg, u32 data)
+{
+	if (reg == RCAR_DMAOR)
+		writew(data, dmac->dmac_base + reg);
+	else
+		writel(data, dmac->dmac_base + reg);
+}
+
+static u32 rcar_dmac_read(struct rcar_dmac *dmac, u32 reg)
+{
+	if (reg == RCAR_DMAOR)
+		return readw(dmac->dmac_base + reg);
+	else
+		return readl(dmac->dmac_base + reg);
+}
+
+static u32 rcar_dmac_chan_read(struct rcar_dmac_chan *chan, u32 reg)
+{
+	if (reg == RCAR_DMARS)
+		return readw(chan->iomem + reg);
+	else
+		return readl(chan->iomem + reg);
+}
+
+static void rcar_dmac_chan_write(struct rcar_dmac_chan *chan, u32 reg, u32 data)
+{
+	if (reg == RCAR_DMARS)
+		writew(data, chan->iomem + reg);
+	else
+		writel(data, chan->iomem + reg);
+}
+
+static void rcar_dmac_chan_clear(struct rcar_dmac *dmac,
+				 struct rcar_dmac_chan *chan)
+{
+	if (dmac->chan_base)
+		rcar_dmac_chan_write(chan, RCAR_GEN4_DMACHCLR, 1);
+	else
+		rcar_dmac_write(dmac, RCAR_DMACHCLR, BIT(chan->index));
+}
+
+static void rcar_dmac_chan_clear_all(struct rcar_dmac *dmac)
+{
+	struct rcar_dmac_chan *chan;
+	unsigned int i;
+
+	if (dmac->chan_base) {
+		for_each_rcar_dmac_chan(i, dmac, chan)
+			rcar_dmac_chan_write(chan, RCAR_GEN4_DMACHCLR, 1);
+	} else {
+		rcar_dmac_write(dmac, RCAR_DMACHCLR, dmac->channels_mask);
+	}
+}
+
+/* -----------------------------------------------------------------------------
+ * Initialization and configuration
+ */
+
+static bool rcar_dmac_chan_is_busy(struct rcar_dmac_chan *chan)
+{
+	u32 chcr = rcar_dmac_chan_read(chan, RCAR_DMACHCR);
+
+	return !!(chcr & (RCAR_DMACHCR_DE | RCAR_DMACHCR_TE));
+}
+
+static void rcar_dmac_chan_start_xfer(struct rcar_dmac_chan *chan)
+{
+	struct rcar_dmac_desc *desc = chan->desc.running;
+	u32 chcr = desc->chcr;
+
+	WARN_ON_ONCE(rcar_dmac_chan_is_busy(chan));
+
+	if (chan->mid_rid >= 0)
+		rcar_dmac_chan_write(chan, RCAR_DMARS, chan->mid_rid);
+
+	if (desc->hwdescs.use) {
+		struct rcar_dmac_xfer_chunk *chunk =
+			list_first_entry(&desc->chunks,
+					 struct rcar_dmac_xfer_chunk, node);
+
+		dev_dbg(chan->chan.device->dev,
+			"chan%u: queue desc %p: %u@%pad\n",
+			chan->index, desc, desc->nchunks, &desc->hwdescs.dma);
+
+#ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT
+		rcar_dmac_chan_write(chan, RCAR_DMAFIXSAR,
+				     chunk->src_addr >> 32);
+		rcar_dmac_chan_write(chan, RCAR_DMAFIXDAR,
+				     chunk->dst_addr >> 32);
+		rcar_dmac_chan_write(chan, RCAR_DMAFIXDPBASE,
+				     desc->hwdescs.dma >> 32);
+#endif
+		rcar_dmac_chan_write(chan, RCAR_DMADPBASE,
+				     (desc->hwdescs.dma & 0xfffffff0) |
+				     RCAR_DMADPBASE_SEL);
+		rcar_dmac_chan_write(chan, RCAR_DMACHCRB,
+				     RCAR_DMACHCRB_DCNT(desc->nchunks - 1) |
+				     RCAR_DMACHCRB_DRST);
+
+		/*
+		 * Errata: When descriptor memory is accessed through an IOMMU
+		 * the DMADAR register isn't initialized automatically from the
+		 * first descriptor at beginning of transfer by the DMAC like it
+		 * should. Initialize it manually with the destination address
+		 * of the first chunk.
+		 */
+		rcar_dmac_chan_write(chan, RCAR_DMADAR,
+				     chunk->dst_addr & 0xffffffff);
+
+		/*
+		 * Program the descriptor stage interrupt to occur after the end
+		 * of the first stage.
+		 */
+		rcar_dmac_chan_write(chan, RCAR_DMADPCR, RCAR_DMADPCR_DIPT(1));
+
+		chcr |= RCAR_DMACHCR_RPT_SAR | RCAR_DMACHCR_RPT_DAR
+		     |  RCAR_DMACHCR_RPT_TCR | RCAR_DMACHCR_DPB;
+
+		/*
+		 * If the descriptor isn't cyclic enable normal descriptor mode
+		 * and the transfer completion interrupt.
+		 */
+		if (!desc->cyclic)
+			chcr |= RCAR_DMACHCR_DPM_ENABLED | RCAR_DMACHCR_IE;
+		/*
+		 * If the descriptor is cyclic and has a callback enable the
+		 * descriptor stage interrupt in infinite repeat mode.
+		 */
+		else if (desc->async_tx.callback)
+			chcr |= RCAR_DMACHCR_DPM_INFINITE | RCAR_DMACHCR_DSIE;
+		/*
+		 * Otherwise just select infinite repeat mode without any
+		 * interrupt.
+		 */
+		else
+			chcr |= RCAR_DMACHCR_DPM_INFINITE;
+	} else {
+		struct rcar_dmac_xfer_chunk *chunk = desc->running;
+
+		dev_dbg(chan->chan.device->dev,
+			"chan%u: queue chunk %p: %u@%pad -> %pad\n",
+			chan->index, chunk, chunk->size, &chunk->src_addr,
+			&chunk->dst_addr);
+
+#ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT
+		rcar_dmac_chan_write(chan, RCAR_DMAFIXSAR,
+				     chunk->src_addr >> 32);
+		rcar_dmac_chan_write(chan, RCAR_DMAFIXDAR,
+				     chunk->dst_addr >> 32);
+#endif
+		rcar_dmac_chan_write(chan, RCAR_DMASAR,
+				     chunk->src_addr & 0xffffffff);
+		rcar_dmac_chan_write(chan, RCAR_DMADAR,
+				     chunk->dst_addr & 0xffffffff);
+		rcar_dmac_chan_write(chan, RCAR_DMATCR,
+				     chunk->size >> desc->xfer_shift);
+
+		chcr |= RCAR_DMACHCR_DPM_DISABLED | RCAR_DMACHCR_IE;
+	}
+
+	rcar_dmac_chan_write(chan, RCAR_DMACHCR,
+			     chcr | RCAR_DMACHCR_DE | RCAR_DMACHCR_CAIE);
+}
+
+static int rcar_dmac_init(struct rcar_dmac *dmac)
+{
+	u16 dmaor;
+
+	/* Clear all channels and enable the DMAC globally. */
+	rcar_dmac_chan_clear_all(dmac);
+	rcar_dmac_write(dmac, RCAR_DMAOR,
+			RCAR_DMAOR_PRI_FIXED | RCAR_DMAOR_DME);
+
+	dmaor = rcar_dmac_read(dmac, RCAR_DMAOR);
+	if ((dmaor & (RCAR_DMAOR_AE | RCAR_DMAOR_DME)) != RCAR_DMAOR_DME) {
+		dev_warn(dmac->dev, "DMAOR initialization failed.\n");
+		return -EIO;
+	}
+
+	return 0;
+}
+
+/* -----------------------------------------------------------------------------
+ * Descriptors submission
+ */
+
+static dma_cookie_t rcar_dmac_tx_submit(struct dma_async_tx_descriptor *tx)
+{
+	struct rcar_dmac_chan *chan = to_rcar_dmac_chan(tx->chan);
+	struct rcar_dmac_desc *desc = to_rcar_dmac_desc(tx);
+	unsigned long flags;
+	dma_cookie_t cookie;
+
+	spin_lock_irqsave(&chan->lock, flags);
+
+	cookie = dma_cookie_assign(tx);
+
+	dev_dbg(chan->chan.device->dev, "chan%u: submit #%d@%p\n",
+		chan->index, tx->cookie, desc);
+
+	list_add_tail(&desc->node, &chan->desc.pending);
+	desc->running = list_first_entry(&desc->chunks,
+					 struct rcar_dmac_xfer_chunk, node);
+
+	spin_unlock_irqrestore(&chan->lock, flags);
+
+	return cookie;
+}
+
+/* -----------------------------------------------------------------------------
+ * Descriptors allocation and free
+ */
+
+/*
+ * rcar_dmac_desc_alloc - Allocate a page worth of DMA descriptors
+ * @chan: the DMA channel
+ * @gfp: allocation flags
+ */
+static int rcar_dmac_desc_alloc(struct rcar_dmac_chan *chan, gfp_t gfp)
+{
+	struct rcar_dmac_desc_page *page;
+	unsigned long flags;
+	LIST_HEAD(list);
+	unsigned int i;
+
+	page = (void *)get_zeroed_page(gfp);
+	if (!page)
+		return -ENOMEM;
+
+	for (i = 0; i < RCAR_DMAC_DESCS_PER_PAGE; ++i) {
+		struct rcar_dmac_desc *desc = &page->descs[i];
+
+		dma_async_tx_descriptor_init(&desc->async_tx, &chan->chan);
+		desc->async_tx.tx_submit = rcar_dmac_tx_submit;
+		INIT_LIST_HEAD(&desc->chunks);
+
+		list_add_tail(&desc->node, &list);
+	}
+
+	spin_lock_irqsave(&chan->lock, flags);
+	list_splice_tail(&list, &chan->desc.free);
+	list_add_tail(&page->node, &chan->desc.pages);
+	spin_unlock_irqrestore(&chan->lock, flags);
+
+	return 0;
+}
+
+/*
+ * rcar_dmac_desc_put - Release a DMA transfer descriptor
+ * @chan: the DMA channel
+ * @desc: the descriptor
+ *
+ * Put the descriptor and its transfer chunk descriptors back in the channel's
+ * free descriptors lists. The descriptor's chunks list will be reinitialized to
+ * an empty list as a result.
+ *
+ * The descriptor must have been removed from the channel's lists before calling
+ * this function.
+ */
+static void rcar_dmac_desc_put(struct rcar_dmac_chan *chan,
+			       struct rcar_dmac_desc *desc)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&chan->lock, flags);
+	list_splice_tail_init(&desc->chunks, &chan->desc.chunks_free);
+	list_add(&desc->node, &chan->desc.free);
+	spin_unlock_irqrestore(&chan->lock, flags);
+}
+
+static void rcar_dmac_desc_recycle_acked(struct rcar_dmac_chan *chan)
+{
+	struct rcar_dmac_desc *desc, *_desc;
+	unsigned long flags;
+	LIST_HEAD(list);
+
+	/*
+	 * We have to temporarily move all descriptors from the wait list to a
+	 * local list as iterating over the wait list, even with
+	 * list_for_each_entry_safe, isn't safe if we release the channel lock
+	 * around the rcar_dmac_desc_put() call.
+	 */
+	spin_lock_irqsave(&chan->lock, flags);
+	list_splice_init(&chan->desc.wait, &list);
+	spin_unlock_irqrestore(&chan->lock, flags);
+
+	list_for_each_entry_safe(desc, _desc, &list, node) {
+		if (async_tx_test_ack(&desc->async_tx)) {
+			list_del(&desc->node);
+			rcar_dmac_desc_put(chan, desc);
+		}
+	}
+
+	if (list_empty(&list))
+		return;
+
+	/* Put the remaining descriptors back in the wait list. */
+	spin_lock_irqsave(&chan->lock, flags);
+	list_splice(&list, &chan->desc.wait);
+	spin_unlock_irqrestore(&chan->lock, flags);
+}
+
+/*
+ * rcar_dmac_desc_get - Allocate a descriptor for a DMA transfer
+ * @chan: the DMA channel
+ *
+ * Locking: This function must be called in a non-atomic context.
+ *
+ * Return: A pointer to the allocated descriptor or NULL if no descriptor can
+ * be allocated.
+ */
+static struct rcar_dmac_desc *rcar_dmac_desc_get(struct rcar_dmac_chan *chan)
+{
+	struct rcar_dmac_desc *desc;
+	unsigned long flags;
+	int ret;
+
+	/* Recycle acked descriptors before attempting allocation. */
+	rcar_dmac_desc_recycle_acked(chan);
+
+	spin_lock_irqsave(&chan->lock, flags);
+
+	while (list_empty(&chan->desc.free)) {
+		/*
+		 * No free descriptors, allocate a page worth of them and try
+		 * again, as someone else could race us to get the newly
+		 * allocated descriptors. If the allocation fails return an
+		 * error.
+		 */
+		spin_unlock_irqrestore(&chan->lock, flags);
+		ret = rcar_dmac_desc_alloc(chan, GFP_NOWAIT);
+		if (ret < 0)
+			return NULL;
+		spin_lock_irqsave(&chan->lock, flags);
+	}
+
+	desc = list_first_entry(&chan->desc.free, struct rcar_dmac_desc, node);
+	list_del(&desc->node);
+
+	spin_unlock_irqrestore(&chan->lock, flags);
+
+	return desc;
+}
+
+/*
+ * rcar_dmac_xfer_chunk_alloc - Allocate a page worth of transfer chunks
+ * @chan: the DMA channel
+ * @gfp: allocation flags
+ */
+static int rcar_dmac_xfer_chunk_alloc(struct rcar_dmac_chan *chan, gfp_t gfp)
+{
+	struct rcar_dmac_desc_page *page;
+	unsigned long flags;
+	LIST_HEAD(list);
+	unsigned int i;
+
+	page = (void *)get_zeroed_page(gfp);
+	if (!page)
+		return -ENOMEM;
+
+	for (i = 0; i < RCAR_DMAC_XFER_CHUNKS_PER_PAGE; ++i) {
+		struct rcar_dmac_xfer_chunk *chunk = &page->chunks[i];
+
+		list_add_tail(&chunk->node, &list);
+	}
+
+	spin_lock_irqsave(&chan->lock, flags);
+	list_splice_tail(&list, &chan->desc.chunks_free);
+	list_add_tail(&page->node, &chan->desc.pages);
+	spin_unlock_irqrestore(&chan->lock, flags);
+
+	return 0;
+}
+
+/*
+ * rcar_dmac_xfer_chunk_get - Allocate a transfer chunk for a DMA transfer
+ * @chan: the DMA channel
+ *
+ * Locking: This function must be called in a non-atomic context.
+ *
+ * Return: A pointer to the allocated transfer chunk descriptor or NULL if no
+ * descriptor can be allocated.
+ */
+static struct rcar_dmac_xfer_chunk *
+rcar_dmac_xfer_chunk_get(struct rcar_dmac_chan *chan)
+{
+	struct rcar_dmac_xfer_chunk *chunk;
+	unsigned long flags;
+	int ret;
+
+	spin_lock_irqsave(&chan->lock, flags);
+
+	while (list_empty(&chan->desc.chunks_free)) {
+		/*
+		 * No free descriptors, allocate a page worth of them and try
+		 * again, as someone else could race us to get the newly
+		 * allocated descriptors. If the allocation fails return an
+		 * error.
+		 */
+		spin_unlock_irqrestore(&chan->lock, flags);
+		ret = rcar_dmac_xfer_chunk_alloc(chan, GFP_NOWAIT);
+		if (ret < 0)
+			return NULL;
+		spin_lock_irqsave(&chan->lock, flags);
+	}
+
+	chunk = list_first_entry(&chan->desc.chunks_free,
+				 struct rcar_dmac_xfer_chunk, node);
+	list_del(&chunk->node);
+
+	spin_unlock_irqrestore(&chan->lock, flags);
+
+	return chunk;
+}
+
+static void rcar_dmac_realloc_hwdesc(struct rcar_dmac_chan *chan,
+				     struct rcar_dmac_desc *desc, size_t size)
+{
+	/*
+	 * dma_alloc_coherent() allocates memory in page size increments. To
+	 * avoid reallocating the hardware descriptors when the allocated size
+	 * wouldn't change align the requested size to a multiple of the page
+	 * size.
+	 */
+	size = PAGE_ALIGN(size);
+
+	if (desc->hwdescs.size == size)
+		return;
+
+	if (desc->hwdescs.mem) {
+		dma_free_coherent(chan->chan.device->dev, desc->hwdescs.size,
+				  desc->hwdescs.mem, desc->hwdescs.dma);
+		desc->hwdescs.mem = NULL;
+		desc->hwdescs.size = 0;
+	}
+
+	if (!size)
+		return;
+
+	desc->hwdescs.mem = dma_alloc_coherent(chan->chan.device->dev, size,
+					       &desc->hwdescs.dma, GFP_NOWAIT);
+	if (!desc->hwdescs.mem)
+		return;
+
+	desc->hwdescs.size = size;
+}
+
+static int rcar_dmac_fill_hwdesc(struct rcar_dmac_chan *chan,
+				 struct rcar_dmac_desc *desc)
+{
+	struct rcar_dmac_xfer_chunk *chunk;
+	struct rcar_dmac_hw_desc *hwdesc;
+
+	rcar_dmac_realloc_hwdesc(chan, desc, desc->nchunks * sizeof(*hwdesc));
+
+	hwdesc = desc->hwdescs.mem;
+	if (!hwdesc)
+		return -ENOMEM;
+
+	list_for_each_entry(chunk, &desc->chunks, node) {
+		hwdesc->sar = chunk->src_addr;
+		hwdesc->dar = chunk->dst_addr;
+		hwdesc->tcr = chunk->size >> desc->xfer_shift;
+		hwdesc++;
+	}
+
+	return 0;
+}
+
+/* -----------------------------------------------------------------------------
+ * Stop and reset
+ */
+static void rcar_dmac_chcr_de_barrier(struct rcar_dmac_chan *chan)
+{
+	u32 chcr;
+	unsigned int i;
+
+	/*
+	 * Ensure that the setting of the DE bit is actually 0 after
+	 * clearing it.
+	 */
+	for (i = 0; i < 1024; i++) {
+		chcr = rcar_dmac_chan_read(chan, RCAR_DMACHCR);
+		if (!(chcr & RCAR_DMACHCR_DE))
+			return;
+		udelay(1);
+	}
+
+	dev_err(chan->chan.device->dev, "CHCR DE check error\n");
+}
+
+static void rcar_dmac_clear_chcr_de(struct rcar_dmac_chan *chan)
+{
+	u32 chcr = rcar_dmac_chan_read(chan, RCAR_DMACHCR);
+
+	/* set DE=0 and flush remaining data */
+	rcar_dmac_chan_write(chan, RCAR_DMACHCR, (chcr & ~RCAR_DMACHCR_DE));
+
+	/* make sure all remaining data was flushed */
+	rcar_dmac_chcr_de_barrier(chan);
+}
+
+static void rcar_dmac_chan_halt(struct rcar_dmac_chan *chan)
+{
+	u32 chcr = rcar_dmac_chan_read(chan, RCAR_DMACHCR);
+
+	chcr &= ~(RCAR_DMACHCR_DSE | RCAR_DMACHCR_DSIE | RCAR_DMACHCR_IE |
+		  RCAR_DMACHCR_TE | RCAR_DMACHCR_DE |
+		  RCAR_DMACHCR_CAE | RCAR_DMACHCR_CAIE);
+	rcar_dmac_chan_write(chan, RCAR_DMACHCR, chcr);
+	rcar_dmac_chcr_de_barrier(chan);
+}
+
+static void rcar_dmac_chan_reinit(struct rcar_dmac_chan *chan)
+{
+	struct rcar_dmac_desc *desc, *_desc;
+	unsigned long flags;
+	LIST_HEAD(descs);
+
+	spin_lock_irqsave(&chan->lock, flags);
+
+	/* Move all non-free descriptors to the local lists. */
+	list_splice_init(&chan->desc.pending, &descs);
+	list_splice_init(&chan->desc.active, &descs);
+	list_splice_init(&chan->desc.done, &descs);
+	list_splice_init(&chan->desc.wait, &descs);
+
+	chan->desc.running = NULL;
+
+	spin_unlock_irqrestore(&chan->lock, flags);
+
+	list_for_each_entry_safe(desc, _desc, &descs, node) {
+		list_del(&desc->node);
+		rcar_dmac_desc_put(chan, desc);
+	}
+}
+
+static void rcar_dmac_stop_all_chan(struct rcar_dmac *dmac)
+{
+	struct rcar_dmac_chan *chan;
+	unsigned int i;
+
+	/* Stop all channels. */
+	for_each_rcar_dmac_chan(i, dmac, chan) {
+		/* Stop and reinitialize the channel. */
+		spin_lock_irq(&chan->lock);
+		rcar_dmac_chan_halt(chan);
+		spin_unlock_irq(&chan->lock);
+	}
+}
+
+static int rcar_dmac_chan_pause(struct dma_chan *chan)
+{
+	unsigned long flags;
+	struct rcar_dmac_chan *rchan = to_rcar_dmac_chan(chan);
+
+	spin_lock_irqsave(&rchan->lock, flags);
+	rcar_dmac_clear_chcr_de(rchan);
+	spin_unlock_irqrestore(&rchan->lock, flags);
+
+	return 0;
+}
+
+/* -----------------------------------------------------------------------------
+ * Descriptors preparation
+ */
+
+static void rcar_dmac_chan_configure_desc(struct rcar_dmac_chan *chan,
+					  struct rcar_dmac_desc *desc)
+{
+	static const u32 chcr_ts[] = {
+		RCAR_DMACHCR_TS_1B, RCAR_DMACHCR_TS_2B,
+		RCAR_DMACHCR_TS_4B, RCAR_DMACHCR_TS_8B,
+		RCAR_DMACHCR_TS_16B, RCAR_DMACHCR_TS_32B,
+		RCAR_DMACHCR_TS_64B,
+	};
+
+	unsigned int xfer_size;
+	u32 chcr;
+
+	switch (desc->direction) {
+	case DMA_DEV_TO_MEM:
+		chcr = RCAR_DMACHCR_DM_INC | RCAR_DMACHCR_SM_FIXED
+		     | RCAR_DMACHCR_RS_DMARS;
+		xfer_size = chan->src.xfer_size;
+		break;
+
+	case DMA_MEM_TO_DEV:
+		chcr = RCAR_DMACHCR_DM_FIXED | RCAR_DMACHCR_SM_INC
+		     | RCAR_DMACHCR_RS_DMARS;
+		xfer_size = chan->dst.xfer_size;
+		break;
+
+	case DMA_MEM_TO_MEM:
+	default:
+		chcr = RCAR_DMACHCR_DM_INC | RCAR_DMACHCR_SM_INC
+		     | RCAR_DMACHCR_RS_AUTO;
+		xfer_size = RCAR_DMAC_MEMCPY_XFER_SIZE;
+		break;
+	}
+
+	desc->xfer_shift = ilog2(xfer_size);
+	desc->chcr = chcr | chcr_ts[desc->xfer_shift];
+}
+
+/*
+ * rcar_dmac_chan_prep_sg - prepare transfer descriptors from an SG list
+ *
+ * Common routine for public (MEMCPY) and slave DMA. The MEMCPY case is also
+ * converted to scatter-gather to guarantee consistent locking and a correct
+ * list manipulation. For slave DMA direction carries the usual meaning, and,
+ * logically, the SG list is RAM and the addr variable contains slave address,
+ * e.g., the FIFO I/O register. For MEMCPY direction equals DMA_MEM_TO_MEM
+ * and the SG list contains only one element and points at the source buffer.
+ */
+static struct dma_async_tx_descriptor *
+rcar_dmac_chan_prep_sg(struct rcar_dmac_chan *chan, struct scatterlist *sgl,
+		       unsigned int sg_len, dma_addr_t dev_addr,
+		       enum dma_transfer_direction dir, unsigned long dma_flags,
+		       bool cyclic)
+{
+	struct rcar_dmac_xfer_chunk *chunk;
+	struct rcar_dmac_desc *desc;
+	struct scatterlist *sg;
+	unsigned int nchunks = 0;
+	unsigned int max_chunk_size;
+	unsigned int full_size = 0;
+	bool cross_boundary = false;
+	unsigned int i;
+#ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT
+	u32 high_dev_addr;
+	u32 high_mem_addr;
+#endif
+
+	desc = rcar_dmac_desc_get(chan);
+	if (!desc)
+		return NULL;
+
+	desc->async_tx.flags = dma_flags;
+	desc->async_tx.cookie = -EBUSY;
+
+	desc->cyclic = cyclic;
+	desc->direction = dir;
+
+	rcar_dmac_chan_configure_desc(chan, desc);
+
+	max_chunk_size = RCAR_DMATCR_MASK << desc->xfer_shift;
+
+	/*
+	 * Allocate and fill the transfer chunk descriptors. We own the only
+	 * reference to the DMA descriptor, there's no need for locking.
+	 */
+	for_each_sg(sgl, sg, sg_len, i) {
+		dma_addr_t mem_addr = sg_dma_address(sg);
+		unsigned int len = sg_dma_len(sg);
+
+		full_size += len;
+
+#ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT
+		if (i == 0) {
+			high_dev_addr = dev_addr >> 32;
+			high_mem_addr = mem_addr >> 32;
+		}
+
+		if ((dev_addr >> 32 != high_dev_addr) ||
+		    (mem_addr >> 32 != high_mem_addr))
+			cross_boundary = true;
+#endif
+		while (len) {
+			unsigned int size = min(len, max_chunk_size);
+
+#ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT
+			/*
+			 * Prevent individual transfers from crossing 4GB
+			 * boundaries.
+			 */
+			if (dev_addr >> 32 != (dev_addr + size - 1) >> 32) {
+				size = ALIGN(dev_addr, 1ULL << 32) - dev_addr;
+				cross_boundary = true;
+			}
+			if (mem_addr >> 32 != (mem_addr + size - 1) >> 32) {
+				size = ALIGN(mem_addr, 1ULL << 32) - mem_addr;
+				cross_boundary = true;
+			}
+#endif
+
+			chunk = rcar_dmac_xfer_chunk_get(chan);
+			if (!chunk) {
+				rcar_dmac_desc_put(chan, desc);
+				return NULL;
+			}
+
+			if (dir == DMA_DEV_TO_MEM) {
+				chunk->src_addr = dev_addr;
+				chunk->dst_addr = mem_addr;
+			} else {
+				chunk->src_addr = mem_addr;
+				chunk->dst_addr = dev_addr;
+			}
+
+			chunk->size = size;
+
+			dev_dbg(chan->chan.device->dev,
+				"chan%u: chunk %p/%p sgl %u@%p, %u/%u %pad -> %pad\n",
+				chan->index, chunk, desc, i, sg, size, len,
+				&chunk->src_addr, &chunk->dst_addr);
+
+			mem_addr += size;
+			if (dir == DMA_MEM_TO_MEM)
+				dev_addr += size;
+
+			len -= size;
+
+			list_add_tail(&chunk->node, &desc->chunks);
+			nchunks++;
+		}
+	}
+
+	desc->nchunks = nchunks;
+	desc->size = full_size;
+
+	/*
+	 * Use hardware descriptor lists if possible when more than one chunk
+	 * needs to be transferred (otherwise they don't make much sense).
+	 *
+	 * Source/Destination address should be located in same 4GiB region
+	 * in the 40bit address space when it uses Hardware descriptor,
+	 * and cross_boundary is checking it.
+	 */
+	desc->hwdescs.use = !cross_boundary && nchunks > 1;
+	if (desc->hwdescs.use) {
+		if (rcar_dmac_fill_hwdesc(chan, desc) < 0)
+			desc->hwdescs.use = false;
+	}
+
+	return &desc->async_tx;
+}
+
+/* -----------------------------------------------------------------------------
+ * DMA engine operations
+ */
+
+static int rcar_dmac_alloc_chan_resources(struct dma_chan *chan)
+{
+	struct rcar_dmac_chan *rchan = to_rcar_dmac_chan(chan);
+	int ret;
+
+	INIT_LIST_HEAD(&rchan->desc.chunks_free);
+	INIT_LIST_HEAD(&rchan->desc.pages);
+
+	/* Preallocate descriptors. */
+	ret = rcar_dmac_xfer_chunk_alloc(rchan, GFP_KERNEL);
+	if (ret < 0)
+		return -ENOMEM;
+
+	ret = rcar_dmac_desc_alloc(rchan, GFP_KERNEL);
+	if (ret < 0)
+		return -ENOMEM;
+
+	return pm_runtime_get_sync(chan->device->dev);
+}
+
+static void rcar_dmac_free_chan_resources(struct dma_chan *chan)
+{
+	struct rcar_dmac_chan *rchan = to_rcar_dmac_chan(chan);
+	struct rcar_dmac *dmac = to_rcar_dmac(chan->device);
+	struct rcar_dmac_chan_map *map = &rchan->map;
+	struct rcar_dmac_desc_page *page, *_page;
+	struct rcar_dmac_desc *desc;
+	LIST_HEAD(list);
+
+	/* Protect against ISR */
+	spin_lock_irq(&rchan->lock);
+	rcar_dmac_chan_halt(rchan);
+	spin_unlock_irq(&rchan->lock);
+
+	/*
+	 * Now no new interrupts will occur, but one might already be
+	 * running. Wait for it to finish before freeing resources.
+	 */
+	synchronize_irq(rchan->irq);
+
+	if (rchan->mid_rid >= 0) {
+		/* The caller is holding dma_list_mutex */
+		clear_bit(rchan->mid_rid, dmac->modules);
+		rchan->mid_rid = -EINVAL;
+	}
+
+	list_splice_init(&rchan->desc.free, &list);
+	list_splice_init(&rchan->desc.pending, &list);
+	list_splice_init(&rchan->desc.active, &list);
+	list_splice_init(&rchan->desc.done, &list);
+	list_splice_init(&rchan->desc.wait, &list);
+
+	rchan->desc.running = NULL;
+
+	list_for_each_entry(desc, &list, node)
+		rcar_dmac_realloc_hwdesc(rchan, desc, 0);
+
+	list_for_each_entry_safe(page, _page, &rchan->desc.pages, node) {
+		list_del(&page->node);
+		free_page((unsigned long)page);
+	}
+
+	/* Remove slave mapping if present. */
+	if (map->slave.xfer_size) {
+		dma_unmap_resource(chan->device->dev, map->addr,
+				   map->slave.xfer_size, map->dir, 0);
+		map->slave.xfer_size = 0;
+	}
+
+	pm_runtime_put(chan->device->dev);
+}
+
+static struct dma_async_tx_descriptor *
+rcar_dmac_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dma_dest,
+			  dma_addr_t dma_src, size_t len, unsigned long flags)
+{
+	struct rcar_dmac_chan *rchan = to_rcar_dmac_chan(chan);
+	struct scatterlist sgl;
+
+	if (!len)
+		return NULL;
+
+	sg_init_table(&sgl, 1);
+	sg_set_page(&sgl, pfn_to_page(PFN_DOWN(dma_src)), len,
+		    offset_in_page(dma_src));
+	sg_dma_address(&sgl) = dma_src;
+	sg_dma_len(&sgl) = len;
+
+	return rcar_dmac_chan_prep_sg(rchan, &sgl, 1, dma_dest,
+				      DMA_MEM_TO_MEM, flags, false);
+}
+
+static int rcar_dmac_map_slave_addr(struct dma_chan *chan,
+				    enum dma_transfer_direction dir)
+{
+	struct rcar_dmac_chan *rchan = to_rcar_dmac_chan(chan);
+	struct rcar_dmac_chan_map *map = &rchan->map;
+	phys_addr_t dev_addr;
+	size_t dev_size;
+	enum dma_data_direction dev_dir;
+
+	if (dir == DMA_DEV_TO_MEM) {
+		dev_addr = rchan->src.slave_addr;
+		dev_size = rchan->src.xfer_size;
+		dev_dir = DMA_TO_DEVICE;
+	} else {
+		dev_addr = rchan->dst.slave_addr;
+		dev_size = rchan->dst.xfer_size;
+		dev_dir = DMA_FROM_DEVICE;
+	}
+
+	/* Reuse current map if possible. */
+	if (dev_addr == map->slave.slave_addr &&
+	    dev_size == map->slave.xfer_size &&
+	    dev_dir == map->dir)
+		return 0;
+
+	/* Remove old mapping if present. */
+	if (map->slave.xfer_size)
+		dma_unmap_resource(chan->device->dev, map->addr,
+				   map->slave.xfer_size, map->dir, 0);
+	map->slave.xfer_size = 0;
+
+	/* Create new slave address map. */
+	map->addr = dma_map_resource(chan->device->dev, dev_addr, dev_size,
+				     dev_dir, 0);
+
+	if (dma_mapping_error(chan->device->dev, map->addr)) {
+		dev_err(chan->device->dev,
+			"chan%u: failed to map %zx@%pap", rchan->index,
+			dev_size, &dev_addr);
+		return -EIO;
+	}
+
+	dev_dbg(chan->device->dev, "chan%u: map %zx@%pap to %pad dir: %s\n",
+		rchan->index, dev_size, &dev_addr, &map->addr,
+		dev_dir == DMA_TO_DEVICE ? "DMA_TO_DEVICE" : "DMA_FROM_DEVICE");
+
+	map->slave.slave_addr = dev_addr;
+	map->slave.xfer_size = dev_size;
+	map->dir = dev_dir;
+
+	return 0;
+}
+
+static struct dma_async_tx_descriptor *
+rcar_dmac_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
+			unsigned int sg_len, enum dma_transfer_direction dir,
+			unsigned long flags, void *context)
+{
+	struct rcar_dmac_chan *rchan = to_rcar_dmac_chan(chan);
+
+	/* Someone calling slave DMA on a generic channel? */
+	if (rchan->mid_rid < 0 || !sg_len || !sg_dma_len(sgl)) {
+		dev_warn(chan->device->dev,
+			 "%s: bad parameter: len=%d, id=%d\n",
+			 __func__, sg_len, rchan->mid_rid);
+		return NULL;
+	}
+
+	if (rcar_dmac_map_slave_addr(chan, dir))
+		return NULL;
+
+	return rcar_dmac_chan_prep_sg(rchan, sgl, sg_len, rchan->map.addr,
+				      dir, flags, false);
+}
+
+#define RCAR_DMAC_MAX_SG_LEN	32
+
+static struct dma_async_tx_descriptor *
+rcar_dmac_prep_dma_cyclic(struct dma_chan *chan, dma_addr_t buf_addr,
+			  size_t buf_len, size_t period_len,
+			  enum dma_transfer_direction dir, unsigned long flags)
+{
+	struct rcar_dmac_chan *rchan = to_rcar_dmac_chan(chan);
+	struct dma_async_tx_descriptor *desc;
+	struct scatterlist *sgl;
+	unsigned int sg_len;
+	unsigned int i;
+
+	/* Someone calling slave DMA on a generic channel? */
+	if (rchan->mid_rid < 0 || buf_len < period_len) {
+		dev_warn(chan->device->dev,
+			"%s: bad parameter: buf_len=%zu, period_len=%zu, id=%d\n",
+			__func__, buf_len, period_len, rchan->mid_rid);
+		return NULL;
+	}
+
+	if (rcar_dmac_map_slave_addr(chan, dir))
+		return NULL;
+
+	sg_len = buf_len / period_len;
+	if (sg_len > RCAR_DMAC_MAX_SG_LEN) {
+		dev_err(chan->device->dev,
+			"chan%u: sg length %d exceeds limit %d",
+			rchan->index, sg_len, RCAR_DMAC_MAX_SG_LEN);
+		return NULL;
+	}
+
+	/*
+	 * Allocate the sg list dynamically as it would consume too much stack
+	 * space.
+	 */
+	sgl = kmalloc_array(sg_len, sizeof(*sgl), GFP_NOWAIT);
+	if (!sgl)
+		return NULL;
+
+	sg_init_table(sgl, sg_len);
+
+	for (i = 0; i < sg_len; ++i) {
+		dma_addr_t src = buf_addr + (period_len * i);
+
+		sg_set_page(&sgl[i], pfn_to_page(PFN_DOWN(src)), period_len,
+			    offset_in_page(src));
+		sg_dma_address(&sgl[i]) = src;
+		sg_dma_len(&sgl[i]) = period_len;
+	}
+
+	desc = rcar_dmac_chan_prep_sg(rchan, sgl, sg_len, rchan->map.addr,
+				      dir, flags, true);
+
+	kfree(sgl);
+	return desc;
+}
+
+static int rcar_dmac_device_config(struct dma_chan *chan,
+				   struct dma_slave_config *cfg)
+{
+	struct rcar_dmac_chan *rchan = to_rcar_dmac_chan(chan);
+
+	/*
+	 * We could lock this, but you shouldn't be configuring the
+	 * channel, while using it...
+	 */
+	rchan->src.slave_addr = cfg->src_addr;
+	rchan->dst.slave_addr = cfg->dst_addr;
+	rchan->src.xfer_size = cfg->src_addr_width;
+	rchan->dst.xfer_size = cfg->dst_addr_width;
+
+	return 0;
+}
+
+static int rcar_dmac_chan_terminate_all(struct dma_chan *chan)
+{
+	struct rcar_dmac_chan *rchan = to_rcar_dmac_chan(chan);
+	unsigned long flags;
+
+	spin_lock_irqsave(&rchan->lock, flags);
+	rcar_dmac_chan_halt(rchan);
+	spin_unlock_irqrestore(&rchan->lock, flags);
+
+	/*
+	 * FIXME: No new interrupt can occur now, but the IRQ thread might still
+	 * be running.
+	 */
+
+	rcar_dmac_chan_reinit(rchan);
+
+	return 0;
+}
+
+static unsigned int rcar_dmac_chan_get_residue(struct rcar_dmac_chan *chan,
+					       dma_cookie_t cookie)
+{
+	struct rcar_dmac_desc *desc = chan->desc.running;
+	struct rcar_dmac_xfer_chunk *running = NULL;
+	struct rcar_dmac_xfer_chunk *chunk;
+	enum dma_status status;
+	unsigned int residue = 0;
+	unsigned int dptr = 0;
+	unsigned int chcrb;
+	unsigned int tcrb;
+	unsigned int i;
+
+	if (!desc)
+		return 0;
+
+	/*
+	 * If the cookie corresponds to a descriptor that has been completed
+	 * there is no residue. The same check has already been performed by the
+	 * caller but without holding the channel lock, so the descriptor could
+	 * now be complete.
+	 */
+	status = dma_cookie_status(&chan->chan, cookie, NULL);
+	if (status == DMA_COMPLETE)
+		return 0;
+
+	/*
+	 * If the cookie doesn't correspond to the currently running transfer
+	 * then the descriptor hasn't been processed yet, and the residue is
+	 * equal to the full descriptor size.
+	 * Also, a client driver is possible to call this function before
+	 * rcar_dmac_isr_channel_thread() runs. In this case, the "desc.running"
+	 * will be the next descriptor, and the done list will appear. So, if
+	 * the argument cookie matches the done list's cookie, we can assume
+	 * the residue is zero.
+	 */
+	if (cookie != desc->async_tx.cookie) {
+		list_for_each_entry(desc, &chan->desc.done, node) {
+			if (cookie == desc->async_tx.cookie)
+				return 0;
+		}
+		list_for_each_entry(desc, &chan->desc.pending, node) {
+			if (cookie == desc->async_tx.cookie)
+				return desc->size;
+		}
+		list_for_each_entry(desc, &chan->desc.active, node) {
+			if (cookie == desc->async_tx.cookie)
+				return desc->size;
+		}
+
+		/*
+		 * No descriptor found for the cookie, there's thus no residue.
+		 * This shouldn't happen if the calling driver passes a correct
+		 * cookie value.
+		 */
+		WARN(1, "No descriptor for cookie!");
+		return 0;
+	}
+
+	/*
+	 * We need to read two registers.
+	 * Make sure the control register does not skip to next chunk
+	 * while reading the counter.
+	 * Trying it 3 times should be enough: Initial read, retry, retry
+	 * for the paranoid.
+	 */
+	for (i = 0; i < 3; i++) {
+		chcrb = rcar_dmac_chan_read(chan, RCAR_DMACHCRB) &
+					    RCAR_DMACHCRB_DPTR_MASK;
+		tcrb = rcar_dmac_chan_read(chan, RCAR_DMATCRB);
+		/* Still the same? */
+		if (chcrb == (rcar_dmac_chan_read(chan, RCAR_DMACHCRB) &
+			      RCAR_DMACHCRB_DPTR_MASK))
+			break;
+	}
+	WARN_ONCE(i >= 3, "residue might be not continuous!");
+
+	/*
+	 * In descriptor mode the descriptor running pointer is not maintained
+	 * by the interrupt handler, find the running descriptor from the
+	 * descriptor pointer field in the CHCRB register. In non-descriptor
+	 * mode just use the running descriptor pointer.
+	 */
+	if (desc->hwdescs.use) {
+		dptr = chcrb >> RCAR_DMACHCRB_DPTR_SHIFT;
+		if (dptr == 0)
+			dptr = desc->nchunks;
+		dptr--;
+		WARN_ON(dptr >= desc->nchunks);
+	} else {
+		running = desc->running;
+	}
+
+	/* Compute the size of all chunks still to be transferred. */
+	list_for_each_entry_reverse(chunk, &desc->chunks, node) {
+		if (chunk == running || ++dptr == desc->nchunks)
+			break;
+
+		residue += chunk->size;
+	}
+
+	/* Add the residue for the current chunk. */
+	residue += tcrb << desc->xfer_shift;
+
+	return residue;
+}
+
+static enum dma_status rcar_dmac_tx_status(struct dma_chan *chan,
+					   dma_cookie_t cookie,
+					   struct dma_tx_state *txstate)
+{
+	struct rcar_dmac_chan *rchan = to_rcar_dmac_chan(chan);
+	enum dma_status status;
+	unsigned long flags;
+	unsigned int residue;
+	bool cyclic;
+
+	status = dma_cookie_status(chan, cookie, txstate);
+	if (status == DMA_COMPLETE || !txstate)
+		return status;
+
+	spin_lock_irqsave(&rchan->lock, flags);
+	residue = rcar_dmac_chan_get_residue(rchan, cookie);
+	cyclic = rchan->desc.running ? rchan->desc.running->cyclic : false;
+	spin_unlock_irqrestore(&rchan->lock, flags);
+
+	/* if there's no residue, the cookie is complete */
+	if (!residue && !cyclic)
+		return DMA_COMPLETE;
+
+	dma_set_residue(txstate, residue);
+
+	return status;
+}
+
+static void rcar_dmac_issue_pending(struct dma_chan *chan)
+{
+	struct rcar_dmac_chan *rchan = to_rcar_dmac_chan(chan);
+	unsigned long flags;
+
+	spin_lock_irqsave(&rchan->lock, flags);
+
+	if (list_empty(&rchan->desc.pending))
+		goto done;
+
+	/* Append the pending list to the active list. */
+	list_splice_tail_init(&rchan->desc.pending, &rchan->desc.active);
+
+	/*
+	 * If no transfer is running pick the first descriptor from the active
+	 * list and start the transfer.
+	 */
+	if (!rchan->desc.running) {
+		struct rcar_dmac_desc *desc;
+
+		desc = list_first_entry(&rchan->desc.active,
+					struct rcar_dmac_desc, node);
+		rchan->desc.running = desc;
+
+		rcar_dmac_chan_start_xfer(rchan);
+	}
+
+done:
+	spin_unlock_irqrestore(&rchan->lock, flags);
+}
+
+static void rcar_dmac_device_synchronize(struct dma_chan *chan)
+{
+	struct rcar_dmac_chan *rchan = to_rcar_dmac_chan(chan);
+
+	synchronize_irq(rchan->irq);
+}
+
+/* -----------------------------------------------------------------------------
+ * IRQ handling
+ */
+
+static irqreturn_t rcar_dmac_isr_desc_stage_end(struct rcar_dmac_chan *chan)
+{
+	struct rcar_dmac_desc *desc = chan->desc.running;
+	unsigned int stage;
+
+	if (WARN_ON(!desc || !desc->cyclic)) {
+		/*
+		 * This should never happen, there should always be a running
+		 * cyclic descriptor when a descriptor stage end interrupt is
+		 * triggered. Warn and return.
+		 */
+		return IRQ_NONE;
+	}
+
+	/* Program the interrupt pointer to the next stage. */
+	stage = (rcar_dmac_chan_read(chan, RCAR_DMACHCRB) &
+		 RCAR_DMACHCRB_DPTR_MASK) >> RCAR_DMACHCRB_DPTR_SHIFT;
+	rcar_dmac_chan_write(chan, RCAR_DMADPCR, RCAR_DMADPCR_DIPT(stage));
+
+	return IRQ_WAKE_THREAD;
+}
+
+static irqreturn_t rcar_dmac_isr_transfer_end(struct rcar_dmac_chan *chan)
+{
+	struct rcar_dmac_desc *desc = chan->desc.running;
+	irqreturn_t ret = IRQ_WAKE_THREAD;
+
+	if (WARN_ON_ONCE(!desc)) {
+		/*
+		 * This should never happen, there should always be a running
+		 * descriptor when a transfer end interrupt is triggered. Warn
+		 * and return.
+		 */
+		return IRQ_NONE;
+	}
+
+	/*
+	 * The transfer end interrupt isn't generated for each chunk when using
+	 * descriptor mode. Only update the running chunk pointer in
+	 * non-descriptor mode.
+	 */
+	if (!desc->hwdescs.use) {
+		/*
+		 * If we haven't completed the last transfer chunk simply move
+		 * to the next one. Only wake the IRQ thread if the transfer is
+		 * cyclic.
+		 */
+		if (!list_is_last(&desc->running->node, &desc->chunks)) {
+			desc->running = list_next_entry(desc->running, node);
+			if (!desc->cyclic)
+				ret = IRQ_HANDLED;
+			goto done;
+		}
+
+		/*
+		 * We've completed the last transfer chunk. If the transfer is
+		 * cyclic, move back to the first one.
+		 */
+		if (desc->cyclic) {
+			desc->running =
+				list_first_entry(&desc->chunks,
+						 struct rcar_dmac_xfer_chunk,
+						 node);
+			goto done;
+		}
+	}
+
+	/* The descriptor is complete, move it to the done list. */
+	list_move_tail(&desc->node, &chan->desc.done);
+
+	/* Queue the next descriptor, if any. */
+	if (!list_empty(&chan->desc.active))
+		chan->desc.running = list_first_entry(&chan->desc.active,
+						      struct rcar_dmac_desc,
+						      node);
+	else
+		chan->desc.running = NULL;
+
+done:
+	if (chan->desc.running)
+		rcar_dmac_chan_start_xfer(chan);
+
+	return ret;
+}
+
+static irqreturn_t rcar_dmac_isr_channel(int irq, void *dev)
+{
+	u32 mask = RCAR_DMACHCR_DSE | RCAR_DMACHCR_TE;
+	struct rcar_dmac_chan *chan = dev;
+	irqreturn_t ret = IRQ_NONE;
+	bool reinit = false;
+	u32 chcr;
+
+	spin_lock(&chan->lock);
+
+	chcr = rcar_dmac_chan_read(chan, RCAR_DMACHCR);
+	if (chcr & RCAR_DMACHCR_CAE) {
+		struct rcar_dmac *dmac = to_rcar_dmac(chan->chan.device);
+
+		/*
+		 * We don't need to call rcar_dmac_chan_halt()
+		 * because channel is already stopped in error case.
+		 * We need to clear register and check DE bit as recovery.
+		 */
+		rcar_dmac_chan_clear(dmac, chan);
+		rcar_dmac_chcr_de_barrier(chan);
+		reinit = true;
+		goto spin_lock_end;
+	}
+
+	if (chcr & RCAR_DMACHCR_TE)
+		mask |= RCAR_DMACHCR_DE;
+	rcar_dmac_chan_write(chan, RCAR_DMACHCR, chcr & ~mask);
+	if (mask & RCAR_DMACHCR_DE)
+		rcar_dmac_chcr_de_barrier(chan);
+
+	if (chcr & RCAR_DMACHCR_DSE)
+		ret |= rcar_dmac_isr_desc_stage_end(chan);
+
+	if (chcr & RCAR_DMACHCR_TE)
+		ret |= rcar_dmac_isr_transfer_end(chan);
+
+spin_lock_end:
+	spin_unlock(&chan->lock);
+
+	if (reinit) {
+		dev_err(chan->chan.device->dev, "Channel Address Error\n");
+
+		rcar_dmac_chan_reinit(chan);
+		ret = IRQ_HANDLED;
+	}
+
+	return ret;
+}
+
+static irqreturn_t rcar_dmac_isr_channel_thread(int irq, void *dev)
+{
+	struct rcar_dmac_chan *chan = dev;
+	struct rcar_dmac_desc *desc;
+	struct dmaengine_desc_callback cb;
+
+	spin_lock_irq(&chan->lock);
+
+	/* For cyclic transfers notify the user after every chunk. */
+	if (chan->desc.running && chan->desc.running->cyclic) {
+		desc = chan->desc.running;
+		dmaengine_desc_get_callback(&desc->async_tx, &cb);
+
+		if (dmaengine_desc_callback_valid(&cb)) {
+			spin_unlock_irq(&chan->lock);
+			dmaengine_desc_callback_invoke(&cb, NULL);
+			spin_lock_irq(&chan->lock);
+		}
+	}
+
+	/*
+	 * Call the callback function for all descriptors on the done list and
+	 * move them to the ack wait list.
+	 */
+	while (!list_empty(&chan->desc.done)) {
+		desc = list_first_entry(&chan->desc.done, struct rcar_dmac_desc,
+					node);
+		dma_cookie_complete(&desc->async_tx);
+		list_del(&desc->node);
+
+		dmaengine_desc_get_callback(&desc->async_tx, &cb);
+		if (dmaengine_desc_callback_valid(&cb)) {
+			spin_unlock_irq(&chan->lock);
+			/*
+			 * We own the only reference to this descriptor, we can
+			 * safely dereference it without holding the channel
+			 * lock.
+			 */
+			dmaengine_desc_callback_invoke(&cb, NULL);
+			spin_lock_irq(&chan->lock);
+		}
+
+		list_add_tail(&desc->node, &chan->desc.wait);
+	}
+
+	spin_unlock_irq(&chan->lock);
+
+	/* Recycle all acked descriptors. */
+	rcar_dmac_desc_recycle_acked(chan);
+
+	return IRQ_HANDLED;
+}
+
+/* -----------------------------------------------------------------------------
+ * OF xlate and channel filter
+ */
+
+static bool rcar_dmac_chan_filter(struct dma_chan *chan, void *arg)
+{
+	struct rcar_dmac *dmac = to_rcar_dmac(chan->device);
+	struct of_phandle_args *dma_spec = arg;
+
+	/*
+	 * FIXME: Using a filter on OF platforms is a nonsense. The OF xlate
+	 * function knows from which device it wants to allocate a channel from,
+	 * and would be perfectly capable of selecting the channel it wants.
+	 * Forcing it to call dma_request_channel() and iterate through all
+	 * channels from all controllers is just pointless.
+	 */
+	if (chan->device->device_config != rcar_dmac_device_config)
+		return false;
+
+	return !test_and_set_bit(dma_spec->args[0], dmac->modules);
+}
+
+static struct dma_chan *rcar_dmac_of_xlate(struct of_phandle_args *dma_spec,
+					   struct of_dma *ofdma)
+{
+	struct rcar_dmac_chan *rchan;
+	struct dma_chan *chan;
+	dma_cap_mask_t mask;
+
+	if (dma_spec->args_count != 1)
+		return NULL;
+
+	/* Only slave DMA channels can be allocated via DT */
+	dma_cap_zero(mask);
+	dma_cap_set(DMA_SLAVE, mask);
+
+	chan = __dma_request_channel(&mask, rcar_dmac_chan_filter, dma_spec,
+				     ofdma->of_node);
+	if (!chan)
+		return NULL;
+
+	rchan = to_rcar_dmac_chan(chan);
+	rchan->mid_rid = dma_spec->args[0];
+
+	return chan;
+}
+
+/* -----------------------------------------------------------------------------
+ * Power management
+ */
+
+#ifdef CONFIG_PM
+static int rcar_dmac_runtime_suspend(struct device *dev)
+{
+	return 0;
+}
+
+static int rcar_dmac_runtime_resume(struct device *dev)
+{
+	struct rcar_dmac *dmac = dev_get_drvdata(dev);
+
+	return rcar_dmac_init(dmac);
+}
+#endif
+
+static const struct dev_pm_ops rcar_dmac_pm = {
+	/*
+	 * TODO for system sleep/resume:
+	 *   - Wait for the current transfer to complete and stop the device,
+	 *   - Resume transfers, if any.
+	 */
+	SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
+				      pm_runtime_force_resume)
+	SET_RUNTIME_PM_OPS(rcar_dmac_runtime_suspend, rcar_dmac_runtime_resume,
+			   NULL)
+};
+
+/* -----------------------------------------------------------------------------
+ * Probe and remove
+ */
+
+static int rcar_dmac_chan_probe(struct rcar_dmac *dmac,
+				struct rcar_dmac_chan *rchan)
+{
+	struct platform_device *pdev = to_platform_device(dmac->dev);
+	struct dma_chan *chan = &rchan->chan;
+	char pdev_irqname[5];
+	char *irqname;
+	int ret;
+
+	rchan->mid_rid = -EINVAL;
+
+	spin_lock_init(&rchan->lock);
+
+	INIT_LIST_HEAD(&rchan->desc.free);
+	INIT_LIST_HEAD(&rchan->desc.pending);
+	INIT_LIST_HEAD(&rchan->desc.active);
+	INIT_LIST_HEAD(&rchan->desc.done);
+	INIT_LIST_HEAD(&rchan->desc.wait);
+
+	/* Request the channel interrupt. */
+	sprintf(pdev_irqname, "ch%u", rchan->index);
+	rchan->irq = platform_get_irq_byname(pdev, pdev_irqname);
+	if (rchan->irq < 0)
+		return -ENODEV;
+
+	irqname = devm_kasprintf(dmac->dev, GFP_KERNEL, "%s:%u",
+				 dev_name(dmac->dev), rchan->index);
+	if (!irqname)
+		return -ENOMEM;
+
+	/*
+	 * Initialize the DMA engine channel and add it to the DMA engine
+	 * channels list.
+	 */
+	chan->device = &dmac->engine;
+	dma_cookie_init(chan);
+
+	list_add_tail(&chan->device_node, &dmac->engine.channels);
+
+	ret = devm_request_threaded_irq(dmac->dev, rchan->irq,
+					rcar_dmac_isr_channel,
+					rcar_dmac_isr_channel_thread, 0,
+					irqname, rchan);
+	if (ret) {
+		dev_err(dmac->dev, "failed to request IRQ %u (%d)\n",
+			rchan->irq, ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+#define RCAR_DMAC_MAX_CHANNELS	32
+
+static int rcar_dmac_parse_of(struct device *dev, struct rcar_dmac *dmac)
+{
+	struct device_node *np = dev->of_node;
+	int ret;
+
+	ret = of_property_read_u32(np, "dma-channels", &dmac->n_channels);
+	if (ret < 0) {
+		dev_err(dev, "unable to read dma-channels property\n");
+		return ret;
+	}
+
+	/* The hardware and driver don't support more than 32 bits in CHCLR */
+	if (dmac->n_channels <= 0 ||
+	    dmac->n_channels >= RCAR_DMAC_MAX_CHANNELS) {
+		dev_err(dev, "invalid number of channels %u\n",
+			dmac->n_channels);
+		return -EINVAL;
+	}
+
+	/*
+	 * If the driver is unable to read dma-channel-mask property,
+	 * the driver assumes that it can use all channels.
+	 */
+	dmac->channels_mask = GENMASK(dmac->n_channels - 1, 0);
+	of_property_read_u32(np, "dma-channel-mask", &dmac->channels_mask);
+
+	/* If the property has out-of-channel mask, this driver clears it */
+	dmac->channels_mask &= GENMASK(dmac->n_channels - 1, 0);
+
+	return 0;
+}
+
+static int rcar_dmac_probe(struct platform_device *pdev)
+{
+	const enum dma_slave_buswidth widths = DMA_SLAVE_BUSWIDTH_1_BYTE |
+		DMA_SLAVE_BUSWIDTH_2_BYTES | DMA_SLAVE_BUSWIDTH_4_BYTES |
+		DMA_SLAVE_BUSWIDTH_8_BYTES | DMA_SLAVE_BUSWIDTH_16_BYTES |
+		DMA_SLAVE_BUSWIDTH_32_BYTES | DMA_SLAVE_BUSWIDTH_64_BYTES;
+	const struct rcar_dmac_of_data *data;
+	struct rcar_dmac_chan *chan;
+	struct dma_device *engine;
+	void __iomem *chan_base;
+	struct rcar_dmac *dmac;
+	unsigned int i;
+	int ret;
+
+	data = of_device_get_match_data(&pdev->dev);
+	if (!data)
+		return -EINVAL;
+
+	dmac = devm_kzalloc(&pdev->dev, sizeof(*dmac), GFP_KERNEL);
+	if (!dmac)
+		return -ENOMEM;
+
+	dmac->dev = &pdev->dev;
+	platform_set_drvdata(pdev, dmac);
+	ret = dma_set_max_seg_size(dmac->dev, RCAR_DMATCR_MASK);
+	if (ret)
+		return ret;
+
+	ret = dma_set_mask_and_coherent(dmac->dev, DMA_BIT_MASK(40));
+	if (ret)
+		return ret;
+
+	ret = rcar_dmac_parse_of(&pdev->dev, dmac);
+	if (ret < 0)
+		return ret;
+
+	/*
+	 * A still unconfirmed hardware bug prevents the IPMMU microTLB 0 to be
+	 * flushed correctly, resulting in memory corruption. DMAC 0 channel 0
+	 * is connected to microTLB 0 on currently supported platforms, so we
+	 * can't use it with the IPMMU. As the IOMMU API operates at the device
+	 * level we can't disable it selectively, so ignore channel 0 for now if
+	 * the device is part of an IOMMU group.
+	 */
+	if (device_iommu_mapped(&pdev->dev))
+		dmac->channels_mask &= ~BIT(0);
+
+	dmac->channels = devm_kcalloc(&pdev->dev, dmac->n_channels,
+				      sizeof(*dmac->channels), GFP_KERNEL);
+	if (!dmac->channels)
+		return -ENOMEM;
+
+	/* Request resources. */
+	dmac->dmac_base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(dmac->dmac_base))
+		return PTR_ERR(dmac->dmac_base);
+
+	if (!data->chan_offset_base) {
+		dmac->chan_base = devm_platform_ioremap_resource(pdev, 1);
+		if (IS_ERR(dmac->chan_base))
+			return PTR_ERR(dmac->chan_base);
+
+		chan_base = dmac->chan_base;
+	} else {
+		chan_base = dmac->dmac_base + data->chan_offset_base;
+	}
+
+	for_each_rcar_dmac_chan(i, dmac, chan) {
+		chan->index = i;
+		chan->iomem = chan_base + i * data->chan_offset_stride;
+	}
+
+	/* Enable runtime PM and initialize the device. */
+	pm_runtime_enable(&pdev->dev);
+	ret = pm_runtime_resume_and_get(&pdev->dev);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "runtime PM get sync failed (%d)\n", ret);
+		goto err_pm_disable;
+	}
+
+	ret = rcar_dmac_init(dmac);
+	pm_runtime_put(&pdev->dev);
+
+	if (ret) {
+		dev_err(&pdev->dev, "failed to reset device\n");
+		goto err_pm_disable;
+	}
+
+	/* Initialize engine */
+	engine = &dmac->engine;
+
+	dma_cap_set(DMA_MEMCPY, engine->cap_mask);
+	dma_cap_set(DMA_SLAVE, engine->cap_mask);
+
+	engine->dev		= &pdev->dev;
+	engine->copy_align	= ilog2(RCAR_DMAC_MEMCPY_XFER_SIZE);
+
+	engine->src_addr_widths	= widths;
+	engine->dst_addr_widths	= widths;
+	engine->directions	= BIT(DMA_MEM_TO_DEV) | BIT(DMA_DEV_TO_MEM);
+	engine->residue_granularity = DMA_RESIDUE_GRANULARITY_BURST;
+
+	engine->device_alloc_chan_resources	= rcar_dmac_alloc_chan_resources;
+	engine->device_free_chan_resources	= rcar_dmac_free_chan_resources;
+	engine->device_prep_dma_memcpy		= rcar_dmac_prep_dma_memcpy;
+	engine->device_prep_slave_sg		= rcar_dmac_prep_slave_sg;
+	engine->device_prep_dma_cyclic		= rcar_dmac_prep_dma_cyclic;
+	engine->device_config			= rcar_dmac_device_config;
+	engine->device_pause			= rcar_dmac_chan_pause;
+	engine->device_terminate_all		= rcar_dmac_chan_terminate_all;
+	engine->device_tx_status		= rcar_dmac_tx_status;
+	engine->device_issue_pending		= rcar_dmac_issue_pending;
+	engine->device_synchronize		= rcar_dmac_device_synchronize;
+
+	INIT_LIST_HEAD(&engine->channels);
+
+	for_each_rcar_dmac_chan(i, dmac, chan) {
+		ret = rcar_dmac_chan_probe(dmac, chan);
+		if (ret < 0)
+			goto err_pm_disable;
+	}
+
+	/* Register the DMAC as a DMA provider for DT. */
+	ret = of_dma_controller_register(pdev->dev.of_node, rcar_dmac_of_xlate,
+					 NULL);
+	if (ret < 0)
+		goto err_pm_disable;
+
+	/*
+	 * Register the DMA engine device.
+	 *
+	 * Default transfer size of 32 bytes requires 32-byte alignment.
+	 */
+	ret = dma_async_device_register(engine);
+	if (ret < 0)
+		goto err_dma_free;
+
+	return 0;
+
+err_dma_free:
+	of_dma_controller_free(pdev->dev.of_node);
+err_pm_disable:
+	pm_runtime_disable(&pdev->dev);
+	return ret;
+}
+
+static int rcar_dmac_remove(struct platform_device *pdev)
+{
+	struct rcar_dmac *dmac = platform_get_drvdata(pdev);
+
+	of_dma_controller_free(pdev->dev.of_node);
+	dma_async_device_unregister(&dmac->engine);
+
+	pm_runtime_disable(&pdev->dev);
+
+	return 0;
+}
+
+static void rcar_dmac_shutdown(struct platform_device *pdev)
+{
+	struct rcar_dmac *dmac = platform_get_drvdata(pdev);
+
+	rcar_dmac_stop_all_chan(dmac);
+}
+
+static const struct rcar_dmac_of_data rcar_dmac_data = {
+	.chan_offset_base	= 0x8000,
+	.chan_offset_stride	= 0x80,
+};
+
+static const struct rcar_dmac_of_data rcar_gen4_dmac_data = {
+	.chan_offset_base	= 0x0,
+	.chan_offset_stride	= 0x1000,
+};
+
+static const struct of_device_id rcar_dmac_of_ids[] = {
+	{
+		.compatible = "renesas,rcar-dmac",
+		.data = &rcar_dmac_data,
+	}, {
+		.compatible = "renesas,rcar-gen4-dmac",
+		.data = &rcar_gen4_dmac_data,
+	}, {
+		.compatible = "renesas,dmac-r8a779a0",
+		.data = &rcar_gen4_dmac_data,
+	},
+	{ /* Sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, rcar_dmac_of_ids);
+
+static struct platform_driver rcar_dmac_driver = {
+	.driver		= {
+		.pm	= &rcar_dmac_pm,
+		.name	= "rcar-dmac",
+		.of_match_table = rcar_dmac_of_ids,
+	},
+	.probe		= rcar_dmac_probe,
+	.remove		= rcar_dmac_remove,
+	.shutdown	= rcar_dmac_shutdown,
+};
+
+module_platform_driver(rcar_dmac_driver);
+
+MODULE_DESCRIPTION("R-Car Gen2 DMA Controller Driver");
+MODULE_AUTHOR("Laurent Pinchart <laurent.pinchart@ideasonboard.com>");
+MODULE_LICENSE("GPL v2");