1 files changed, 699 insertions, 0 deletions

diff --git a/drivers/dma/moxart-dma.c b/drivers/dma/moxart-dma.c
new file mode 100644
index 000000000000..3258e484e4f6
--- /dev/null
+++ b/drivers/dma/moxart-dma.c
@@ -0,0 +1,699 @@
+/*
+ * MOXA ART SoCs DMA Engine support.
+ *
+ * Copyright (C) 2013 Jonas Jensen
+ *
+ * Jonas Jensen <jonas.jensen@gmail.com>
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2.  This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#include <linux/dmaengine.h>
+#include <linux/dma-mapping.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/list.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/of_dma.h>
+#include <linux/bitops.h>
+
+#include <asm/cacheflush.h>
+
+#include "dmaengine.h"
+#include "virt-dma.h"
+
+#define APB_DMA_MAX_CHANNEL			4
+
+#define REG_OFF_ADDRESS_SOURCE			0
+#define REG_OFF_ADDRESS_DEST			4
+#define REG_OFF_CYCLES				8
+#define REG_OFF_CTRL				12
+#define REG_OFF_CHAN_SIZE			16
+
+#define APB_DMA_ENABLE				BIT(0)
+#define APB_DMA_FIN_INT_STS			BIT(1)
+#define APB_DMA_FIN_INT_EN			BIT(2)
+#define APB_DMA_BURST_MODE			BIT(3)
+#define APB_DMA_ERR_INT_STS			BIT(4)
+#define APB_DMA_ERR_INT_EN			BIT(5)
+
+/*
+ * Unset: APB
+ * Set:   AHB
+ */
+#define APB_DMA_SOURCE_SELECT			0x40
+#define APB_DMA_DEST_SELECT			0x80
+
+#define APB_DMA_SOURCE				0x100
+#define APB_DMA_DEST				0x1000
+
+#define APB_DMA_SOURCE_MASK			0x700
+#define APB_DMA_DEST_MASK			0x7000
+
+/*
+ * 000: No increment
+ * 001: +1 (Burst=0), +4  (Burst=1)
+ * 010: +2 (Burst=0), +8  (Burst=1)
+ * 011: +4 (Burst=0), +16 (Burst=1)
+ * 101: -1 (Burst=0), -4  (Burst=1)
+ * 110: -2 (Burst=0), -8  (Burst=1)
+ * 111: -4 (Burst=0), -16 (Burst=1)
+ */
+#define APB_DMA_SOURCE_INC_0			0
+#define APB_DMA_SOURCE_INC_1_4			0x100
+#define APB_DMA_SOURCE_INC_2_8			0x200
+#define APB_DMA_SOURCE_INC_4_16			0x300
+#define APB_DMA_SOURCE_DEC_1_4			0x500
+#define APB_DMA_SOURCE_DEC_2_8			0x600
+#define APB_DMA_SOURCE_DEC_4_16			0x700
+#define APB_DMA_DEST_INC_0			0
+#define APB_DMA_DEST_INC_1_4			0x1000
+#define APB_DMA_DEST_INC_2_8			0x2000
+#define APB_DMA_DEST_INC_4_16			0x3000
+#define APB_DMA_DEST_DEC_1_4			0x5000
+#define APB_DMA_DEST_DEC_2_8			0x6000
+#define APB_DMA_DEST_DEC_4_16			0x7000
+
+/*
+ * Request signal select source/destination address for DMA hardware handshake.
+ *
+ * The request line number is a property of the DMA controller itself,
+ * e.g. MMC must always request channels where dma_slave_config->slave_id is 5.
+ *
+ * 0:    No request / Grant signal
+ * 1-15: Request    / Grant signal
+ */
+#define APB_DMA_SOURCE_REQ_NO			0x1000000
+#define APB_DMA_SOURCE_REQ_NO_MASK		0xf000000
+#define APB_DMA_DEST_REQ_NO			0x10000
+#define APB_DMA_DEST_REQ_NO_MASK		0xf0000
+
+#define APB_DMA_DATA_WIDTH			0x100000
+#define APB_DMA_DATA_WIDTH_MASK			0x300000
+/*
+ * Data width of transfer:
+ *
+ * 00: Word
+ * 01: Half
+ * 10: Byte
+ */
+#define APB_DMA_DATA_WIDTH_4			0
+#define APB_DMA_DATA_WIDTH_2			0x100000
+#define APB_DMA_DATA_WIDTH_1			0x200000
+
+#define APB_DMA_CYCLES_MASK			0x00ffffff
+
+#define MOXART_DMA_DATA_TYPE_S8			0x00
+#define MOXART_DMA_DATA_TYPE_S16		0x01
+#define MOXART_DMA_DATA_TYPE_S32		0x02
+
+struct moxart_sg {
+	dma_addr_t addr;
+	uint32_t len;
+};
+
+struct moxart_desc {
+	enum dma_transfer_direction	dma_dir;
+	dma_addr_t			dev_addr;
+	unsigned int			sglen;
+	unsigned int			dma_cycles;
+	struct virt_dma_desc		vd;
+	uint8_t				es;
+	struct moxart_sg		sg[0];
+};
+
+struct moxart_chan {
+	struct virt_dma_chan		vc;
+
+	void __iomem			*base;
+	struct moxart_desc		*desc;
+
+	struct dma_slave_config		cfg;
+
+	bool				allocated;
+	bool				error;
+	int				ch_num;
+	unsigned int			line_reqno;
+	unsigned int			sgidx;
+};
+
+struct moxart_dmadev {
+	struct dma_device		dma_slave;
+	struct moxart_chan		slave_chans[APB_DMA_MAX_CHANNEL];
+};
+
+struct moxart_filter_data {
+	struct moxart_dmadev		*mdc;
+	struct of_phandle_args		*dma_spec;
+};
+
+static const unsigned int es_bytes[] = {
+	[MOXART_DMA_DATA_TYPE_S8] = 1,
+	[MOXART_DMA_DATA_TYPE_S16] = 2,
+	[MOXART_DMA_DATA_TYPE_S32] = 4,
+};
+
+static struct device *chan2dev(struct dma_chan *chan)
+{
+	return &chan->dev->device;
+}
+
+static inline struct moxart_chan *to_moxart_dma_chan(struct dma_chan *c)
+{
+	return container_of(c, struct moxart_chan, vc.chan);
+}
+
+static inline struct moxart_desc *to_moxart_dma_desc(
+	struct dma_async_tx_descriptor *t)
+{
+	return container_of(t, struct moxart_desc, vd.tx);
+}
+
+static void moxart_dma_desc_free(struct virt_dma_desc *vd)
+{
+	kfree(container_of(vd, struct moxart_desc, vd));
+}
+
+static int moxart_terminate_all(struct dma_chan *chan)
+{
+	struct moxart_chan *ch = to_moxart_dma_chan(chan);
+	unsigned long flags;
+	LIST_HEAD(head);
+	u32 ctrl;
+
+	dev_dbg(chan2dev(chan), "%s: ch=%p\n", __func__, ch);
+
+	spin_lock_irqsave(&ch->vc.lock, flags);
+
+	if (ch->desc)
+		ch->desc = NULL;
+
+	ctrl = readl(ch->base + REG_OFF_CTRL);
+	ctrl &= ~(APB_DMA_ENABLE | APB_DMA_FIN_INT_EN | APB_DMA_ERR_INT_EN);
+	writel(ctrl, ch->base + REG_OFF_CTRL);
+
+	vchan_get_all_descriptors(&ch->vc, &head);
+	spin_unlock_irqrestore(&ch->vc.lock, flags);
+	vchan_dma_desc_free_list(&ch->vc, &head);
+
+	return 0;
+}
+
+static int moxart_slave_config(struct dma_chan *chan,
+			       struct dma_slave_config *cfg)
+{
+	struct moxart_chan *ch = to_moxart_dma_chan(chan);
+	u32 ctrl;
+
+	ch->cfg = *cfg;
+
+	ctrl = readl(ch->base + REG_OFF_CTRL);
+	ctrl |= APB_DMA_BURST_MODE;
+	ctrl &= ~(APB_DMA_DEST_MASK | APB_DMA_SOURCE_MASK);
+	ctrl &= ~(APB_DMA_DEST_REQ_NO_MASK | APB_DMA_SOURCE_REQ_NO_MASK);
+
+	switch (ch->cfg.src_addr_width) {
+	case DMA_SLAVE_BUSWIDTH_1_BYTE:
+		ctrl |= APB_DMA_DATA_WIDTH_1;
+		if (ch->cfg.direction != DMA_MEM_TO_DEV)
+			ctrl |= APB_DMA_DEST_INC_1_4;
+		else
+			ctrl |= APB_DMA_SOURCE_INC_1_4;
+		break;
+	case DMA_SLAVE_BUSWIDTH_2_BYTES:
+		ctrl |= APB_DMA_DATA_WIDTH_2;
+		if (ch->cfg.direction != DMA_MEM_TO_DEV)
+			ctrl |= APB_DMA_DEST_INC_2_8;
+		else
+			ctrl |= APB_DMA_SOURCE_INC_2_8;
+		break;
+	case DMA_SLAVE_BUSWIDTH_4_BYTES:
+		ctrl &= ~APB_DMA_DATA_WIDTH;
+		if (ch->cfg.direction != DMA_MEM_TO_DEV)
+			ctrl |= APB_DMA_DEST_INC_4_16;
+		else
+			ctrl |= APB_DMA_SOURCE_INC_4_16;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	if (ch->cfg.direction == DMA_MEM_TO_DEV) {
+		ctrl &= ~APB_DMA_DEST_SELECT;
+		ctrl |= APB_DMA_SOURCE_SELECT;
+		ctrl |= (ch->line_reqno << 16 &
+			 APB_DMA_DEST_REQ_NO_MASK);
+	} else {
+		ctrl |= APB_DMA_DEST_SELECT;
+		ctrl &= ~APB_DMA_SOURCE_SELECT;
+		ctrl |= (ch->line_reqno << 24 &
+			 APB_DMA_SOURCE_REQ_NO_MASK);
+	}
+
+	writel(ctrl, ch->base + REG_OFF_CTRL);
+
+	return 0;
+}
+
+static int moxart_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd,
+			  unsigned long arg)
+{
+	int ret = 0;
+
+	switch (cmd) {
+	case DMA_PAUSE:
+	case DMA_RESUME:
+		return -EINVAL;
+	case DMA_TERMINATE_ALL:
+		moxart_terminate_all(chan);
+		break;
+	case DMA_SLAVE_CONFIG:
+		ret = moxart_slave_config(chan, (struct dma_slave_config *)arg);
+		break;
+	default:
+		ret = -ENOSYS;
+	}
+
+	return ret;
+}
+
+static struct dma_async_tx_descriptor *moxart_prep_slave_sg(
+	struct dma_chan *chan, struct scatterlist *sgl,
+	unsigned int sg_len, enum dma_transfer_direction dir,
+	unsigned long tx_flags, void *context)
+{
+	struct moxart_chan *ch = to_moxart_dma_chan(chan);
+	struct moxart_desc *d;
+	enum dma_slave_buswidth dev_width;
+	dma_addr_t dev_addr;
+	struct scatterlist *sgent;
+	unsigned int es;
+	unsigned int i;
+
+	if (!is_slave_direction(dir)) {
+		dev_err(chan2dev(chan), "%s: invalid DMA direction\n",
+			__func__);
+		return NULL;
+	}
+
+	if (dir == DMA_DEV_TO_MEM) {
+		dev_addr = ch->cfg.src_addr;
+		dev_width = ch->cfg.src_addr_width;
+	} else {
+		dev_addr = ch->cfg.dst_addr;
+		dev_width = ch->cfg.dst_addr_width;
+	}
+
+	switch (dev_width) {
+	case DMA_SLAVE_BUSWIDTH_1_BYTE:
+		es = MOXART_DMA_DATA_TYPE_S8;
+		break;
+	case DMA_SLAVE_BUSWIDTH_2_BYTES:
+		es = MOXART_DMA_DATA_TYPE_S16;
+		break;
+	case DMA_SLAVE_BUSWIDTH_4_BYTES:
+		es = MOXART_DMA_DATA_TYPE_S32;
+		break;
+	default:
+		dev_err(chan2dev(chan), "%s: unsupported data width (%u)\n",
+			__func__, dev_width);
+		return NULL;
+	}
+
+	d = kzalloc(sizeof(*d) + sg_len * sizeof(d->sg[0]), GFP_ATOMIC);
+	if (!d)
+		return NULL;
+
+	d->dma_dir = dir;
+	d->dev_addr = dev_addr;
+	d->es = es;
+
+	for_each_sg(sgl, sgent, sg_len, i) {
+		d->sg[i].addr = sg_dma_address(sgent);
+		d->sg[i].len = sg_dma_len(sgent);
+	}
+
+	d->sglen = sg_len;
+
+	ch->error = 0;
+
+	return vchan_tx_prep(&ch->vc, &d->vd, tx_flags);
+}
+
+static struct dma_chan *moxart_of_xlate(struct of_phandle_args *dma_spec,
+					struct of_dma *ofdma)
+{
+	struct moxart_dmadev *mdc = ofdma->of_dma_data;
+	struct dma_chan *chan;
+	struct moxart_chan *ch;
+
+	chan = dma_get_any_slave_channel(&mdc->dma_slave);
+	if (!chan)
+		return NULL;
+
+	ch = to_moxart_dma_chan(chan);
+	ch->line_reqno = dma_spec->args[0];
+
+	return chan;
+}
+
+static int moxart_alloc_chan_resources(struct dma_chan *chan)
+{
+	struct moxart_chan *ch = to_moxart_dma_chan(chan);
+
+	dev_dbg(chan2dev(chan), "%s: allocating channel #%u\n",
+		__func__, ch->ch_num);
+	ch->allocated = 1;
+
+	return 0;
+}
+
+static void moxart_free_chan_resources(struct dma_chan *chan)
+{
+	struct moxart_chan *ch = to_moxart_dma_chan(chan);
+
+	vchan_free_chan_resources(&ch->vc);
+
+	dev_dbg(chan2dev(chan), "%s: freeing channel #%u\n",
+		__func__, ch->ch_num);
+	ch->allocated = 0;
+}
+
+static void moxart_dma_set_params(struct moxart_chan *ch, dma_addr_t src_addr,
+				  dma_addr_t dst_addr)
+{
+	writel(src_addr, ch->base + REG_OFF_ADDRESS_SOURCE);
+	writel(dst_addr, ch->base + REG_OFF_ADDRESS_DEST);
+}
+
+static void moxart_set_transfer_params(struct moxart_chan *ch, unsigned int len)
+{
+	struct moxart_desc *d = ch->desc;
+	unsigned int sglen_div = es_bytes[d->es];
+
+	d->dma_cycles = len >> sglen_div;
+
+	/*
+	 * There are 4 cycles on 64 bytes copied, i.e. one cycle copies 16
+	 * bytes ( when width is APB_DMAB_DATA_WIDTH_4 ).
+	 */
+	writel(d->dma_cycles, ch->base + REG_OFF_CYCLES);
+
+	dev_dbg(chan2dev(&ch->vc.chan), "%s: set %u DMA cycles (len=%u)\n",
+		__func__, d->dma_cycles, len);
+}
+
+static void moxart_start_dma(struct moxart_chan *ch)
+{
+	u32 ctrl;
+
+	ctrl = readl(ch->base + REG_OFF_CTRL);
+	ctrl |= (APB_DMA_ENABLE | APB_DMA_FIN_INT_EN | APB_DMA_ERR_INT_EN);
+	writel(ctrl, ch->base + REG_OFF_CTRL);
+}
+
+static void moxart_dma_start_sg(struct moxart_chan *ch, unsigned int idx)
+{
+	struct moxart_desc *d = ch->desc;
+	struct moxart_sg *sg = ch->desc->sg + idx;
+
+	if (ch->desc->dma_dir == DMA_MEM_TO_DEV)
+		moxart_dma_set_params(ch, sg->addr, d->dev_addr);
+	else if (ch->desc->dma_dir == DMA_DEV_TO_MEM)
+		moxart_dma_set_params(ch, d->dev_addr, sg->addr);
+
+	moxart_set_transfer_params(ch, sg->len);
+
+	moxart_start_dma(ch);
+}
+
+static void moxart_dma_start_desc(struct dma_chan *chan)
+{
+	struct moxart_chan *ch = to_moxart_dma_chan(chan);
+	struct virt_dma_desc *vd;
+
+	vd = vchan_next_desc(&ch->vc);
+
+	if (!vd) {
+		ch->desc = NULL;
+		return;
+	}
+
+	list_del(&vd->node);
+
+	ch->desc = to_moxart_dma_desc(&vd->tx);
+	ch->sgidx = 0;
+
+	moxart_dma_start_sg(ch, 0);
+}
+
+static void moxart_issue_pending(struct dma_chan *chan)
+{
+	struct moxart_chan *ch = to_moxart_dma_chan(chan);
+	unsigned long flags;
+
+	spin_lock_irqsave(&ch->vc.lock, flags);
+	if (vchan_issue_pending(&ch->vc) && !ch->desc)
+		moxart_dma_start_desc(chan);
+	spin_unlock_irqrestore(&ch->vc.lock, flags);
+}
+
+static size_t moxart_dma_desc_size(struct moxart_desc *d,
+				   unsigned int completed_sgs)
+{
+	unsigned int i;
+	size_t size;
+
+	for (size = i = completed_sgs; i < d->sglen; i++)
+		size += d->sg[i].len;
+
+	return size;
+}
+
+static size_t moxart_dma_desc_size_in_flight(struct moxart_chan *ch)
+{
+	size_t size;
+	unsigned int completed_cycles, cycles;
+
+	size = moxart_dma_desc_size(ch->desc, ch->sgidx);
+	cycles = readl(ch->base + REG_OFF_CYCLES);
+	completed_cycles = (ch->desc->dma_cycles - cycles);
+	size -= completed_cycles << es_bytes[ch->desc->es];
+
+	dev_dbg(chan2dev(&ch->vc.chan), "%s: size=%zu\n", __func__, size);
+
+	return size;
+}
+
+static enum dma_status moxart_tx_status(struct dma_chan *chan,
+					dma_cookie_t cookie,
+					struct dma_tx_state *txstate)
+{
+	struct moxart_chan *ch = to_moxart_dma_chan(chan);
+	struct virt_dma_desc *vd;
+	struct moxart_desc *d;
+	enum dma_status ret;
+	unsigned long flags;
+
+	/*
+	 * dma_cookie_status() assigns initial residue value.
+	 */
+	ret = dma_cookie_status(chan, cookie, txstate);
+
+	spin_lock_irqsave(&ch->vc.lock, flags);
+	vd = vchan_find_desc(&ch->vc, cookie);
+	if (vd) {
+		d = to_moxart_dma_desc(&vd->tx);
+		txstate->residue = moxart_dma_desc_size(d, 0);
+	} else if (ch->desc && ch->desc->vd.tx.cookie == cookie) {
+		txstate->residue = moxart_dma_desc_size_in_flight(ch);
+	}
+	spin_unlock_irqrestore(&ch->vc.lock, flags);
+
+	if (ch->error)
+		return DMA_ERROR;
+
+	return ret;
+}
+
+static void moxart_dma_init(struct dma_device *dma, struct device *dev)
+{
+	dma->device_prep_slave_sg		= moxart_prep_slave_sg;
+	dma->device_alloc_chan_resources	= moxart_alloc_chan_resources;
+	dma->device_free_chan_resources		= moxart_free_chan_resources;
+	dma->device_issue_pending		= moxart_issue_pending;
+	dma->device_tx_status			= moxart_tx_status;
+	dma->device_control			= moxart_control;
+	dma->dev				= dev;
+
+	INIT_LIST_HEAD(&dma->channels);
+}
+
+static irqreturn_t moxart_dma_interrupt(int irq, void *devid)
+{
+	struct moxart_dmadev *mc = devid;
+	struct moxart_chan *ch = &mc->slave_chans[0];
+	unsigned int i;
+	unsigned long flags;
+	u32 ctrl;
+
+	dev_dbg(chan2dev(&ch->vc.chan), "%s\n", __func__);
+
+	for (i = 0; i < APB_DMA_MAX_CHANNEL; i++, ch++) {
+		if (!ch->allocated)
+			continue;
+
+		ctrl = readl(ch->base + REG_OFF_CTRL);
+
+		dev_dbg(chan2dev(&ch->vc.chan), "%s: ch=%p ch->base=%p ctrl=%x\n",
+			__func__, ch, ch->base, ctrl);
+
+		if (ctrl & APB_DMA_FIN_INT_STS) {
+			ctrl &= ~APB_DMA_FIN_INT_STS;
+			if (ch->desc) {
+				spin_lock_irqsave(&ch->vc.lock, flags);
+				if (++ch->sgidx < ch->desc->sglen) {
+					moxart_dma_start_sg(ch, ch->sgidx);
+				} else {
+					vchan_cookie_complete(&ch->desc->vd);
+					moxart_dma_start_desc(&ch->vc.chan);
+				}
+				spin_unlock_irqrestore(&ch->vc.lock, flags);
+			}
+		}
+
+		if (ctrl & APB_DMA_ERR_INT_STS) {
+			ctrl &= ~APB_DMA_ERR_INT_STS;
+			ch->error = 1;
+		}
+
+		writel(ctrl, ch->base + REG_OFF_CTRL);
+	}
+
+	return IRQ_HANDLED;
+}
+
+static int moxart_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct device_node *node = dev->of_node;
+	struct resource *res;
+	static void __iomem *dma_base_addr;
+	int ret, i;
+	unsigned int irq;
+	struct moxart_chan *ch;
+	struct moxart_dmadev *mdc;
+
+	mdc = devm_kzalloc(dev, sizeof(*mdc), GFP_KERNEL);
+	if (!mdc) {
+		dev_err(dev, "can't allocate DMA container\n");
+		return -ENOMEM;
+	}
+
+	irq = irq_of_parse_and_map(node, 0);
+	if (irq == NO_IRQ) {
+		dev_err(dev, "no IRQ resource\n");
+		return -EINVAL;
+	}
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	dma_base_addr = devm_ioremap_resource(dev, res);
+	if (IS_ERR(dma_base_addr))
+		return PTR_ERR(dma_base_addr);
+
+	dma_cap_zero(mdc->dma_slave.cap_mask);
+	dma_cap_set(DMA_SLAVE, mdc->dma_slave.cap_mask);
+	dma_cap_set(DMA_PRIVATE, mdc->dma_slave.cap_mask);
+
+	moxart_dma_init(&mdc->dma_slave, dev);
+
+	ch = &mdc->slave_chans[0];
+	for (i = 0; i < APB_DMA_MAX_CHANNEL; i++, ch++) {
+		ch->ch_num = i;
+		ch->base = dma_base_addr + i * REG_OFF_CHAN_SIZE;
+		ch->allocated = 0;
+
+		ch->vc.desc_free = moxart_dma_desc_free;
+		vchan_init(&ch->vc, &mdc->dma_slave);
+
+		dev_dbg(dev, "%s: chs[%d]: ch->ch_num=%u ch->base=%p\n",
+			__func__, i, ch->ch_num, ch->base);
+	}
+
+	platform_set_drvdata(pdev, mdc);
+
+	ret = devm_request_irq(dev, irq, moxart_dma_interrupt, 0,
+			       "moxart-dma-engine", mdc);
+	if (ret) {
+		dev_err(dev, "devm_request_irq failed\n");
+		return ret;
+	}
+
+	ret = dma_async_device_register(&mdc->dma_slave);
+	if (ret) {
+		dev_err(dev, "dma_async_device_register failed\n");
+		return ret;
+	}
+
+	ret = of_dma_controller_register(node, moxart_of_xlate, mdc);
+	if (ret) {
+		dev_err(dev, "of_dma_controller_register failed\n");
+		dma_async_device_unregister(&mdc->dma_slave);
+		return ret;
+	}
+
+	dev_dbg(dev, "%s: IRQ=%u\n", __func__, irq);
+
+	return 0;
+}
+
+static int moxart_remove(struct platform_device *pdev)
+{
+	struct moxart_dmadev *m = platform_get_drvdata(pdev);
+
+	dma_async_device_unregister(&m->dma_slave);
+
+	if (pdev->dev.of_node)
+		of_dma_controller_free(pdev->dev.of_node);
+
+	return 0;
+}
+
+static const struct of_device_id moxart_dma_match[] = {
+	{ .compatible = "moxa,moxart-dma" },
+	{ }
+};
+
+static struct platform_driver moxart_driver = {
+	.probe	= moxart_probe,
+	.remove	= moxart_remove,
+	.driver = {
+		.name		= "moxart-dma-engine",
+		.owner		= THIS_MODULE,
+		.of_match_table	= moxart_dma_match,
+	},
+};
+
+static int moxart_init(void)
+{
+	return platform_driver_register(&moxart_driver);
+}
+subsys_initcall(moxart_init);
+
+static void __exit moxart_exit(void)
+{
+	platform_driver_unregister(&moxart_driver);
+}
+module_exit(moxart_exit);
+
+MODULE_AUTHOR("Jonas Jensen <jonas.jensen@gmail.com>");
+MODULE_DESCRIPTION("MOXART DMA engine driver");
+MODULE_LICENSE("GPL v2");