Linux-libre 4.3.2-gnu

1 files changed, 691 insertions, 0 deletions

diff --git a/drivers/dma/dma-axi-dmac.c b/drivers/dma/dma-axi-dmac.c
new file mode 100644
index 000000000..5b2395e7e
--- /dev/null
+++ b/drivers/dma/dma-axi-dmac.c
@@ -0,0 +1,691 @@
+/*
+ * Driver for the Analog Devices AXI-DMAC core
+ *
+ * Copyright 2013-2015 Analog Devices Inc.
+ *  Author: Lars-Peter Clausen <lars@metafoo.de>
+ *
+ * Licensed under the GPL-2.
+ */
+
+#include <linux/clk.h>
+#include <linux/device.h>
+#include <linux/dma-mapping.h>
+#include <linux/dmaengine.h>
+#include <linux/err.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_dma.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+
+#include <dt-bindings/dma/axi-dmac.h>
+
+#include "dmaengine.h"
+#include "virt-dma.h"
+
+/*
+ * The AXI-DMAC is a soft IP core that is used in FPGA designs. The core has
+ * various instantiation parameters which decided the exact feature set support
+ * by the core.
+ *
+ * Each channel of the core has a source interface and a destination interface.
+ * The number of channels and the type of the channel interfaces is selected at
+ * configuration time. A interface can either be a connected to a central memory
+ * interconnect, which allows access to system memory, or it can be connected to
+ * a dedicated bus which is directly connected to a data port on a peripheral.
+ * Given that those are configuration options of the core that are selected when
+ * it is instantiated this means that they can not be changed by software at
+ * runtime. By extension this means that each channel is uni-directional. It can
+ * either be device to memory or memory to device, but not both. Also since the
+ * device side is a dedicated data bus only connected to a single peripheral
+ * there is no address than can or needs to be configured for the device side.
+ */
+
+#define AXI_DMAC_REG_IRQ_MASK		0x80
+#define AXI_DMAC_REG_IRQ_PENDING	0x84
+#define AXI_DMAC_REG_IRQ_SOURCE		0x88
+
+#define AXI_DMAC_REG_CTRL		0x400
+#define AXI_DMAC_REG_TRANSFER_ID	0x404
+#define AXI_DMAC_REG_START_TRANSFER	0x408
+#define AXI_DMAC_REG_FLAGS		0x40c
+#define AXI_DMAC_REG_DEST_ADDRESS	0x410
+#define AXI_DMAC_REG_SRC_ADDRESS	0x414
+#define AXI_DMAC_REG_X_LENGTH		0x418
+#define AXI_DMAC_REG_Y_LENGTH		0x41c
+#define AXI_DMAC_REG_DEST_STRIDE	0x420
+#define AXI_DMAC_REG_SRC_STRIDE		0x424
+#define AXI_DMAC_REG_TRANSFER_DONE	0x428
+#define AXI_DMAC_REG_ACTIVE_TRANSFER_ID 0x42c
+#define AXI_DMAC_REG_STATUS		0x430
+#define AXI_DMAC_REG_CURRENT_SRC_ADDR	0x434
+#define AXI_DMAC_REG_CURRENT_DEST_ADDR	0x438
+
+#define AXI_DMAC_CTRL_ENABLE		BIT(0)
+#define AXI_DMAC_CTRL_PAUSE		BIT(1)
+
+#define AXI_DMAC_IRQ_SOT		BIT(0)
+#define AXI_DMAC_IRQ_EOT		BIT(1)
+
+#define AXI_DMAC_FLAG_CYCLIC		BIT(0)
+
+struct axi_dmac_sg {
+	dma_addr_t src_addr;
+	dma_addr_t dest_addr;
+	unsigned int x_len;
+	unsigned int y_len;
+	unsigned int dest_stride;
+	unsigned int src_stride;
+	unsigned int id;
+};
+
+struct axi_dmac_desc {
+	struct virt_dma_desc vdesc;
+	bool cyclic;
+
+	unsigned int num_submitted;
+	unsigned int num_completed;
+	unsigned int num_sgs;
+	struct axi_dmac_sg sg[];
+};
+
+struct axi_dmac_chan {
+	struct virt_dma_chan vchan;
+
+	struct axi_dmac_desc *next_desc;
+	struct list_head active_descs;
+	enum dma_transfer_direction direction;
+
+	unsigned int src_width;
+	unsigned int dest_width;
+	unsigned int src_type;
+	unsigned int dest_type;
+
+	unsigned int max_length;
+	unsigned int align_mask;
+
+	bool hw_cyclic;
+	bool hw_2d;
+};
+
+struct axi_dmac {
+	void __iomem *base;
+	int irq;
+
+	struct clk *clk;
+
+	struct dma_device dma_dev;
+	struct axi_dmac_chan chan;
+
+	struct device_dma_parameters dma_parms;
+};
+
+static struct axi_dmac *chan_to_axi_dmac(struct axi_dmac_chan *chan)
+{
+	return container_of(chan->vchan.chan.device, struct axi_dmac,
+		dma_dev);
+}
+
+static struct axi_dmac_chan *to_axi_dmac_chan(struct dma_chan *c)
+{
+	return container_of(c, struct axi_dmac_chan, vchan.chan);
+}
+
+static struct axi_dmac_desc *to_axi_dmac_desc(struct virt_dma_desc *vdesc)
+{
+	return container_of(vdesc, struct axi_dmac_desc, vdesc);
+}
+
+static void axi_dmac_write(struct axi_dmac *axi_dmac, unsigned int reg,
+	unsigned int val)
+{
+	writel(val, axi_dmac->base + reg);
+}
+
+static int axi_dmac_read(struct axi_dmac *axi_dmac, unsigned int reg)
+{
+	return readl(axi_dmac->base + reg);
+}
+
+static int axi_dmac_src_is_mem(struct axi_dmac_chan *chan)
+{
+	return chan->src_type == AXI_DMAC_BUS_TYPE_AXI_MM;
+}
+
+static int axi_dmac_dest_is_mem(struct axi_dmac_chan *chan)
+{
+	return chan->dest_type == AXI_DMAC_BUS_TYPE_AXI_MM;
+}
+
+static bool axi_dmac_check_len(struct axi_dmac_chan *chan, unsigned int len)
+{
+	if (len == 0 || len > chan->max_length)
+		return false;
+	if ((len & chan->align_mask) != 0) /* Not aligned */
+		return false;
+	return true;
+}
+
+static bool axi_dmac_check_addr(struct axi_dmac_chan *chan, dma_addr_t addr)
+{
+	if ((addr & chan->align_mask) != 0) /* Not aligned */
+		return false;
+	return true;
+}
+
+static void axi_dmac_start_transfer(struct axi_dmac_chan *chan)
+{
+	struct axi_dmac *dmac = chan_to_axi_dmac(chan);
+	struct virt_dma_desc *vdesc;
+	struct axi_dmac_desc *desc;
+	struct axi_dmac_sg *sg;
+	unsigned int flags = 0;
+	unsigned int val;
+
+	val = axi_dmac_read(dmac, AXI_DMAC_REG_START_TRANSFER);
+	if (val) /* Queue is full, wait for the next SOT IRQ */
+		return;
+
+	desc = chan->next_desc;
+
+	if (!desc) {
+		vdesc = vchan_next_desc(&chan->vchan);
+		if (!vdesc)
+			return;
+		list_move_tail(&vdesc->node, &chan->active_descs);
+		desc = to_axi_dmac_desc(vdesc);
+	}
+	sg = &desc->sg[desc->num_submitted];
+
+	desc->num_submitted++;
+	if (desc->num_submitted == desc->num_sgs)
+		chan->next_desc = NULL;
+	else
+		chan->next_desc = desc;
+
+	sg->id = axi_dmac_read(dmac, AXI_DMAC_REG_TRANSFER_ID);
+
+	if (axi_dmac_dest_is_mem(chan)) {
+		axi_dmac_write(dmac, AXI_DMAC_REG_DEST_ADDRESS, sg->dest_addr);
+		axi_dmac_write(dmac, AXI_DMAC_REG_DEST_STRIDE, sg->dest_stride);
+	}
+
+	if (axi_dmac_src_is_mem(chan)) {
+		axi_dmac_write(dmac, AXI_DMAC_REG_SRC_ADDRESS, sg->src_addr);
+		axi_dmac_write(dmac, AXI_DMAC_REG_SRC_STRIDE, sg->src_stride);
+	}
+
+	/*
+	 * If the hardware supports cyclic transfers and there is no callback to
+	 * call, enable hw cyclic mode to avoid unnecessary interrupts.
+	 */
+	if (chan->hw_cyclic && desc->cyclic && !desc->vdesc.tx.callback)
+		flags |= AXI_DMAC_FLAG_CYCLIC;
+
+	axi_dmac_write(dmac, AXI_DMAC_REG_X_LENGTH, sg->x_len - 1);
+	axi_dmac_write(dmac, AXI_DMAC_REG_Y_LENGTH, sg->y_len - 1);
+	axi_dmac_write(dmac, AXI_DMAC_REG_FLAGS, flags);
+	axi_dmac_write(dmac, AXI_DMAC_REG_START_TRANSFER, 1);
+}
+
+static struct axi_dmac_desc *axi_dmac_active_desc(struct axi_dmac_chan *chan)
+{
+	return list_first_entry_or_null(&chan->active_descs,
+		struct axi_dmac_desc, vdesc.node);
+}
+
+static void axi_dmac_transfer_done(struct axi_dmac_chan *chan,
+	unsigned int completed_transfers)
+{
+	struct axi_dmac_desc *active;
+	struct axi_dmac_sg *sg;
+
+	active = axi_dmac_active_desc(chan);
+	if (!active)
+		return;
+
+	if (active->cyclic) {
+		vchan_cyclic_callback(&active->vdesc);
+	} else {
+		do {
+			sg = &active->sg[active->num_completed];
+			if (!(BIT(sg->id) & completed_transfers))
+				break;
+			active->num_completed++;
+			if (active->num_completed == active->num_sgs) {
+				list_del(&active->vdesc.node);
+				vchan_cookie_complete(&active->vdesc);
+				active = axi_dmac_active_desc(chan);
+			}
+		} while (active);
+	}
+}
+
+static irqreturn_t axi_dmac_interrupt_handler(int irq, void *devid)
+{
+	struct axi_dmac *dmac = devid;
+	unsigned int pending;
+
+	pending = axi_dmac_read(dmac, AXI_DMAC_REG_IRQ_PENDING);
+	axi_dmac_write(dmac, AXI_DMAC_REG_IRQ_PENDING, pending);
+
+	spin_lock(&dmac->chan.vchan.lock);
+	/* One or more transfers have finished */
+	if (pending & AXI_DMAC_IRQ_EOT) {
+		unsigned int completed;
+
+		completed = axi_dmac_read(dmac, AXI_DMAC_REG_TRANSFER_DONE);
+		axi_dmac_transfer_done(&dmac->chan, completed);
+	}
+	/* Space has become available in the descriptor queue */
+	if (pending & AXI_DMAC_IRQ_SOT)
+		axi_dmac_start_transfer(&dmac->chan);
+	spin_unlock(&dmac->chan.vchan.lock);
+
+	return IRQ_HANDLED;
+}
+
+static int axi_dmac_terminate_all(struct dma_chan *c)
+{
+	struct axi_dmac_chan *chan = to_axi_dmac_chan(c);
+	struct axi_dmac *dmac = chan_to_axi_dmac(chan);
+	unsigned long flags;
+	LIST_HEAD(head);
+
+	spin_lock_irqsave(&chan->vchan.lock, flags);
+	axi_dmac_write(dmac, AXI_DMAC_REG_CTRL, 0);
+	chan->next_desc = NULL;
+	vchan_get_all_descriptors(&chan->vchan, &head);
+	list_splice_tail_init(&chan->active_descs, &head);
+	spin_unlock_irqrestore(&chan->vchan.lock, flags);
+
+	vchan_dma_desc_free_list(&chan->vchan, &head);
+
+	return 0;
+}
+
+static void axi_dmac_issue_pending(struct dma_chan *c)
+{
+	struct axi_dmac_chan *chan = to_axi_dmac_chan(c);
+	struct axi_dmac *dmac = chan_to_axi_dmac(chan);
+	unsigned long flags;
+
+	axi_dmac_write(dmac, AXI_DMAC_REG_CTRL, AXI_DMAC_CTRL_ENABLE);
+
+	spin_lock_irqsave(&chan->vchan.lock, flags);
+	if (vchan_issue_pending(&chan->vchan))
+		axi_dmac_start_transfer(chan);
+	spin_unlock_irqrestore(&chan->vchan.lock, flags);
+}
+
+static struct axi_dmac_desc *axi_dmac_alloc_desc(unsigned int num_sgs)
+{
+	struct axi_dmac_desc *desc;
+
+	desc = kzalloc(sizeof(struct axi_dmac_desc) +
+		sizeof(struct axi_dmac_sg) * num_sgs, GFP_NOWAIT);
+	if (!desc)
+		return NULL;
+
+	desc->num_sgs = num_sgs;
+
+	return desc;
+}
+
+static struct dma_async_tx_descriptor *axi_dmac_prep_slave_sg(
+	struct dma_chan *c, struct scatterlist *sgl,
+	unsigned int sg_len, enum dma_transfer_direction direction,
+	unsigned long flags, void *context)
+{
+	struct axi_dmac_chan *chan = to_axi_dmac_chan(c);
+	struct axi_dmac_desc *desc;
+	struct scatterlist *sg;
+	unsigned int i;
+
+	if (direction != chan->direction)
+		return NULL;
+
+	desc = axi_dmac_alloc_desc(sg_len);
+	if (!desc)
+		return NULL;
+
+	for_each_sg(sgl, sg, sg_len, i) {
+		if (!axi_dmac_check_addr(chan, sg_dma_address(sg)) ||
+		    !axi_dmac_check_len(chan, sg_dma_len(sg))) {
+			kfree(desc);
+			return NULL;
+		}
+
+		if (direction == DMA_DEV_TO_MEM)
+			desc->sg[i].dest_addr = sg_dma_address(sg);
+		else
+			desc->sg[i].src_addr = sg_dma_address(sg);
+		desc->sg[i].x_len = sg_dma_len(sg);
+		desc->sg[i].y_len = 1;
+	}
+
+	desc->cyclic = false;
+
+	return vchan_tx_prep(&chan->vchan, &desc->vdesc, flags);
+}
+
+static struct dma_async_tx_descriptor *axi_dmac_prep_dma_cyclic(
+	struct dma_chan *c, dma_addr_t buf_addr, size_t buf_len,
+	size_t period_len, enum dma_transfer_direction direction,
+	unsigned long flags)
+{
+	struct axi_dmac_chan *chan = to_axi_dmac_chan(c);
+	struct axi_dmac_desc *desc;
+	unsigned int num_periods, i;
+
+	if (direction != chan->direction)
+		return NULL;
+
+	if (!axi_dmac_check_len(chan, buf_len) ||
+	    !axi_dmac_check_addr(chan, buf_addr))
+		return NULL;
+
+	if (period_len == 0 || buf_len % period_len)
+		return NULL;
+
+	num_periods = buf_len / period_len;
+
+	desc = axi_dmac_alloc_desc(num_periods);
+	if (!desc)
+		return NULL;
+
+	for (i = 0; i < num_periods; i++) {
+		if (direction == DMA_DEV_TO_MEM)
+			desc->sg[i].dest_addr = buf_addr;
+		else
+			desc->sg[i].src_addr = buf_addr;
+		desc->sg[i].x_len = period_len;
+		desc->sg[i].y_len = 1;
+		buf_addr += period_len;
+	}
+
+	desc->cyclic = true;
+
+	return vchan_tx_prep(&chan->vchan, &desc->vdesc, flags);
+}
+
+static struct dma_async_tx_descriptor *axi_dmac_prep_interleaved(
+	struct dma_chan *c, struct dma_interleaved_template *xt,
+	unsigned long flags)
+{
+	struct axi_dmac_chan *chan = to_axi_dmac_chan(c);
+	struct axi_dmac_desc *desc;
+	size_t dst_icg, src_icg;
+
+	if (xt->frame_size != 1)
+		return NULL;
+
+	if (xt->dir != chan->direction)
+		return NULL;
+
+	if (axi_dmac_src_is_mem(chan)) {
+		if (!xt->src_inc || !axi_dmac_check_addr(chan, xt->src_start))
+			return NULL;
+	}
+
+	if (axi_dmac_dest_is_mem(chan)) {
+		if (!xt->dst_inc || !axi_dmac_check_addr(chan, xt->dst_start))
+			return NULL;
+	}
+
+	dst_icg = dmaengine_get_dst_icg(xt, &xt->sgl[0]);
+	src_icg = dmaengine_get_src_icg(xt, &xt->sgl[0]);
+
+	if (chan->hw_2d) {
+		if (!axi_dmac_check_len(chan, xt->sgl[0].size) ||
+		    !axi_dmac_check_len(chan, xt->numf))
+			return NULL;
+		if (xt->sgl[0].size + dst_icg > chan->max_length ||
+		    xt->sgl[0].size + src_icg > chan->max_length)
+			return NULL;
+	} else {
+		if (dst_icg != 0 || src_icg != 0)
+			return NULL;
+		if (chan->max_length / xt->sgl[0].size < xt->numf)
+			return NULL;
+		if (!axi_dmac_check_len(chan, xt->sgl[0].size * xt->numf))
+			return NULL;
+	}
+
+	desc = axi_dmac_alloc_desc(1);
+	if (!desc)
+		return NULL;
+
+	if (axi_dmac_src_is_mem(chan)) {
+		desc->sg[0].src_addr = xt->src_start;
+		desc->sg[0].src_stride = xt->sgl[0].size + src_icg;
+	}
+
+	if (axi_dmac_dest_is_mem(chan)) {
+		desc->sg[0].dest_addr = xt->dst_start;
+		desc->sg[0].dest_stride = xt->sgl[0].size + dst_icg;
+	}
+
+	if (chan->hw_2d) {
+		desc->sg[0].x_len = xt->sgl[0].size;
+		desc->sg[0].y_len = xt->numf;
+	} else {
+		desc->sg[0].x_len = xt->sgl[0].size * xt->numf;
+		desc->sg[0].y_len = 1;
+	}
+
+	return vchan_tx_prep(&chan->vchan, &desc->vdesc, flags);
+}
+
+static void axi_dmac_free_chan_resources(struct dma_chan *c)
+{
+	vchan_free_chan_resources(to_virt_chan(c));
+}
+
+static void axi_dmac_desc_free(struct virt_dma_desc *vdesc)
+{
+	kfree(container_of(vdesc, struct axi_dmac_desc, vdesc));
+}
+
+/*
+ * The configuration stored in the devicetree matches the configuration
+ * parameters of the peripheral instance and allows the driver to know which
+ * features are implemented and how it should behave.
+ */
+static int axi_dmac_parse_chan_dt(struct device_node *of_chan,
+	struct axi_dmac_chan *chan)
+{
+	u32 val;
+	int ret;
+
+	ret = of_property_read_u32(of_chan, "reg", &val);
+	if (ret)
+		return ret;
+
+	/* We only support 1 channel for now */
+	if (val != 0)
+		return -EINVAL;
+
+	ret = of_property_read_u32(of_chan, "adi,source-bus-type", &val);
+	if (ret)
+		return ret;
+	if (val > AXI_DMAC_BUS_TYPE_FIFO)
+		return -EINVAL;
+	chan->src_type = val;
+
+	ret = of_property_read_u32(of_chan, "adi,destination-bus-type", &val);
+	if (ret)
+		return ret;
+	if (val > AXI_DMAC_BUS_TYPE_FIFO)
+		return -EINVAL;
+	chan->dest_type = val;
+
+	ret = of_property_read_u32(of_chan, "adi,source-bus-width", &val);
+	if (ret)
+		return ret;
+	chan->src_width = val / 8;
+
+	ret = of_property_read_u32(of_chan, "adi,destination-bus-width", &val);
+	if (ret)
+		return ret;
+	chan->dest_width = val / 8;
+
+	ret = of_property_read_u32(of_chan, "adi,length-width", &val);
+	if (ret)
+		return ret;
+
+	if (val >= 32)
+		chan->max_length = UINT_MAX;
+	else
+		chan->max_length = (1ULL << val) - 1;
+
+	chan->align_mask = max(chan->dest_width, chan->src_width) - 1;
+
+	if (axi_dmac_dest_is_mem(chan) && axi_dmac_src_is_mem(chan))
+		chan->direction = DMA_MEM_TO_MEM;
+	else if (!axi_dmac_dest_is_mem(chan) && axi_dmac_src_is_mem(chan))
+		chan->direction = DMA_MEM_TO_DEV;
+	else if (axi_dmac_dest_is_mem(chan) && !axi_dmac_src_is_mem(chan))
+		chan->direction = DMA_DEV_TO_MEM;
+	else
+		chan->direction = DMA_DEV_TO_DEV;
+
+	chan->hw_cyclic = of_property_read_bool(of_chan, "adi,cyclic");
+	chan->hw_2d = of_property_read_bool(of_chan, "adi,2d");
+
+	return 0;
+}
+
+static int axi_dmac_probe(struct platform_device *pdev)
+{
+	struct device_node *of_channels, *of_chan;
+	struct dma_device *dma_dev;
+	struct axi_dmac *dmac;
+	struct resource *res;
+	int ret;
+
+	dmac = devm_kzalloc(&pdev->dev, sizeof(*dmac), GFP_KERNEL);
+	if (!dmac)
+		return -ENOMEM;
+
+	dmac->irq = platform_get_irq(pdev, 0);
+	if (dmac->irq <= 0)
+		return -EINVAL;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	dmac->base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(dmac->base))
+		return PTR_ERR(dmac->base);
+
+	dmac->clk = devm_clk_get(&pdev->dev, NULL);
+	if (IS_ERR(dmac->clk))
+		return PTR_ERR(dmac->clk);
+
+	INIT_LIST_HEAD(&dmac->chan.active_descs);
+
+	of_channels = of_get_child_by_name(pdev->dev.of_node, "adi,channels");
+	if (of_channels == NULL)
+		return -ENODEV;
+
+	for_each_child_of_node(of_channels, of_chan) {
+		ret = axi_dmac_parse_chan_dt(of_chan, &dmac->chan);
+		if (ret) {
+			of_node_put(of_chan);
+			of_node_put(of_channels);
+			return -EINVAL;
+		}
+	}
+	of_node_put(of_channels);
+
+	pdev->dev.dma_parms = &dmac->dma_parms;
+	dma_set_max_seg_size(&pdev->dev, dmac->chan.max_length);
+
+	dma_dev = &dmac->dma_dev;
+	dma_cap_set(DMA_SLAVE, dma_dev->cap_mask);
+	dma_cap_set(DMA_CYCLIC, dma_dev->cap_mask);
+	dma_dev->device_free_chan_resources = axi_dmac_free_chan_resources;
+	dma_dev->device_tx_status = dma_cookie_status;
+	dma_dev->device_issue_pending = axi_dmac_issue_pending;
+	dma_dev->device_prep_slave_sg = axi_dmac_prep_slave_sg;
+	dma_dev->device_prep_dma_cyclic = axi_dmac_prep_dma_cyclic;
+	dma_dev->device_prep_interleaved_dma = axi_dmac_prep_interleaved;
+	dma_dev->device_terminate_all = axi_dmac_terminate_all;
+	dma_dev->dev = &pdev->dev;
+	dma_dev->chancnt = 1;
+	dma_dev->src_addr_widths = BIT(dmac->chan.src_width);
+	dma_dev->dst_addr_widths = BIT(dmac->chan.dest_width);
+	dma_dev->directions = BIT(dmac->chan.direction);
+	dma_dev->residue_granularity = DMA_RESIDUE_GRANULARITY_DESCRIPTOR;
+	INIT_LIST_HEAD(&dma_dev->channels);
+
+	dmac->chan.vchan.desc_free = axi_dmac_desc_free;
+	vchan_init(&dmac->chan.vchan, dma_dev);
+
+	ret = clk_prepare_enable(dmac->clk);
+	if (ret < 0)
+		return ret;
+
+	axi_dmac_write(dmac, AXI_DMAC_REG_IRQ_MASK, 0x00);
+
+	ret = dma_async_device_register(dma_dev);
+	if (ret)
+		goto err_clk_disable;
+
+	ret = of_dma_controller_register(pdev->dev.of_node,
+		of_dma_xlate_by_chan_id, dma_dev);
+	if (ret)
+		goto err_unregister_device;
+
+	ret = request_irq(dmac->irq, axi_dmac_interrupt_handler, 0,
+		dev_name(&pdev->dev), dmac);
+	if (ret)
+		goto err_unregister_of;
+
+	platform_set_drvdata(pdev, dmac);
+
+	return 0;
+
+err_unregister_of:
+	of_dma_controller_free(pdev->dev.of_node);
+err_unregister_device:
+	dma_async_device_unregister(&dmac->dma_dev);
+err_clk_disable:
+	clk_disable_unprepare(dmac->clk);
+
+	return ret;
+}
+
+static int axi_dmac_remove(struct platform_device *pdev)
+{
+	struct axi_dmac *dmac = platform_get_drvdata(pdev);
+
+	of_dma_controller_free(pdev->dev.of_node);
+	free_irq(dmac->irq, dmac);
+	tasklet_kill(&dmac->chan.vchan.task);
+	dma_async_device_unregister(&dmac->dma_dev);
+	clk_disable_unprepare(dmac->clk);
+
+	return 0;
+}
+
+static const struct of_device_id axi_dmac_of_match_table[] = {
+	{ .compatible = "adi,axi-dmac-1.00.a" },
+	{ },
+};
+
+static struct platform_driver axi_dmac_driver = {
+	.driver = {
+		.name = "dma-axi-dmac",
+		.of_match_table = axi_dmac_of_match_table,
+	},
+	.probe = axi_dmac_probe,
+	.remove = axi_dmac_remove,
+};
+module_platform_driver(axi_dmac_driver);
+
+MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
+MODULE_DESCRIPTION("DMA controller driver for the AXI-DMAC controller");
+MODULE_LICENSE("GPL v2");