Add the rt linux 4.1.3-rt3 as base
[kvmfornfv.git] / kernel / drivers / dma / dma-jz4740.c
diff --git a/kernel/drivers/dma/dma-jz4740.c b/kernel/drivers/dma/dma-jz4740.c
new file mode 100644 (file)
index 0000000..7638b24
--- /dev/null
@@ -0,0 +1,599 @@
+/*
+ *  Copyright (C) 2013, Lars-Peter Clausen <lars@metafoo.de>
+ *  JZ4740 DMAC support
+ *
+ *  This program is free software; you can redistribute it and/or modify it
+ *  under  the terms of the GNU General         Public License as published by the
+ *  Free Software Foundation;  either version 2 of the License, or (at your
+ *  option) any later version.
+ *
+ */
+
+#include <linux/dmaengine.h>
+#include <linux/dma-mapping.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/list.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/irq.h>
+#include <linux/clk.h>
+
+#include <asm/mach-jz4740/dma.h>
+
+#include "virt-dma.h"
+
+#define JZ_DMA_NR_CHANS 6
+
+#define JZ_REG_DMA_SRC_ADDR(x)         (0x00 + (x) * 0x20)
+#define JZ_REG_DMA_DST_ADDR(x)         (0x04 + (x) * 0x20)
+#define JZ_REG_DMA_TRANSFER_COUNT(x)   (0x08 + (x) * 0x20)
+#define JZ_REG_DMA_REQ_TYPE(x)         (0x0C + (x) * 0x20)
+#define JZ_REG_DMA_STATUS_CTRL(x)      (0x10 + (x) * 0x20)
+#define JZ_REG_DMA_CMD(x)              (0x14 + (x) * 0x20)
+#define JZ_REG_DMA_DESC_ADDR(x)                (0x18 + (x) * 0x20)
+
+#define JZ_REG_DMA_CTRL                        0x300
+#define JZ_REG_DMA_IRQ                 0x304
+#define JZ_REG_DMA_DOORBELL            0x308
+#define JZ_REG_DMA_DOORBELL_SET                0x30C
+
+#define JZ_DMA_STATUS_CTRL_NO_DESC             BIT(31)
+#define JZ_DMA_STATUS_CTRL_DESC_INV            BIT(6)
+#define JZ_DMA_STATUS_CTRL_ADDR_ERR            BIT(4)
+#define JZ_DMA_STATUS_CTRL_TRANSFER_DONE       BIT(3)
+#define JZ_DMA_STATUS_CTRL_HALT                        BIT(2)
+#define JZ_DMA_STATUS_CTRL_COUNT_TERMINATE     BIT(1)
+#define JZ_DMA_STATUS_CTRL_ENABLE              BIT(0)
+
+#define JZ_DMA_CMD_SRC_INC                     BIT(23)
+#define JZ_DMA_CMD_DST_INC                     BIT(22)
+#define JZ_DMA_CMD_RDIL_MASK                   (0xf << 16)
+#define JZ_DMA_CMD_SRC_WIDTH_MASK              (0x3 << 14)
+#define JZ_DMA_CMD_DST_WIDTH_MASK              (0x3 << 12)
+#define JZ_DMA_CMD_INTERVAL_LENGTH_MASK                (0x7 << 8)
+#define JZ_DMA_CMD_BLOCK_MODE                  BIT(7)
+#define JZ_DMA_CMD_DESC_VALID                  BIT(4)
+#define JZ_DMA_CMD_DESC_VALID_MODE             BIT(3)
+#define JZ_DMA_CMD_VALID_IRQ_ENABLE            BIT(2)
+#define JZ_DMA_CMD_TRANSFER_IRQ_ENABLE         BIT(1)
+#define JZ_DMA_CMD_LINK_ENABLE                 BIT(0)
+
+#define JZ_DMA_CMD_FLAGS_OFFSET 22
+#define JZ_DMA_CMD_RDIL_OFFSET 16
+#define JZ_DMA_CMD_SRC_WIDTH_OFFSET 14
+#define JZ_DMA_CMD_DST_WIDTH_OFFSET 12
+#define JZ_DMA_CMD_TRANSFER_SIZE_OFFSET 8
+#define JZ_DMA_CMD_MODE_OFFSET 7
+
+#define JZ_DMA_CTRL_PRIORITY_MASK              (0x3 << 8)
+#define JZ_DMA_CTRL_HALT                       BIT(3)
+#define JZ_DMA_CTRL_ADDRESS_ERROR              BIT(2)
+#define JZ_DMA_CTRL_ENABLE                     BIT(0)
+
+enum jz4740_dma_width {
+       JZ4740_DMA_WIDTH_32BIT  = 0,
+       JZ4740_DMA_WIDTH_8BIT   = 1,
+       JZ4740_DMA_WIDTH_16BIT  = 2,
+};
+
+enum jz4740_dma_transfer_size {
+       JZ4740_DMA_TRANSFER_SIZE_4BYTE  = 0,
+       JZ4740_DMA_TRANSFER_SIZE_1BYTE  = 1,
+       JZ4740_DMA_TRANSFER_SIZE_2BYTE  = 2,
+       JZ4740_DMA_TRANSFER_SIZE_16BYTE = 3,
+       JZ4740_DMA_TRANSFER_SIZE_32BYTE = 4,
+};
+
+enum jz4740_dma_flags {
+       JZ4740_DMA_SRC_AUTOINC = 0x2,
+       JZ4740_DMA_DST_AUTOINC = 0x1,
+};
+
+enum jz4740_dma_mode {
+       JZ4740_DMA_MODE_SINGLE  = 0,
+       JZ4740_DMA_MODE_BLOCK   = 1,
+};
+
+struct jz4740_dma_sg {
+       dma_addr_t addr;
+       unsigned int len;
+};
+
+struct jz4740_dma_desc {
+       struct virt_dma_desc vdesc;
+
+       enum dma_transfer_direction direction;
+       bool cyclic;
+
+       unsigned int num_sgs;
+       struct jz4740_dma_sg sg[];
+};
+
+struct jz4740_dmaengine_chan {
+       struct virt_dma_chan vchan;
+       unsigned int id;
+
+       dma_addr_t fifo_addr;
+       unsigned int transfer_shift;
+
+       struct jz4740_dma_desc *desc;
+       unsigned int next_sg;
+};
+
+struct jz4740_dma_dev {
+       struct dma_device ddev;
+       void __iomem *base;
+       struct clk *clk;
+
+       struct jz4740_dmaengine_chan chan[JZ_DMA_NR_CHANS];
+};
+
+static struct jz4740_dma_dev *jz4740_dma_chan_get_dev(
+       struct jz4740_dmaengine_chan *chan)
+{
+       return container_of(chan->vchan.chan.device, struct jz4740_dma_dev,
+               ddev);
+}
+
+static struct jz4740_dmaengine_chan *to_jz4740_dma_chan(struct dma_chan *c)
+{
+       return container_of(c, struct jz4740_dmaengine_chan, vchan.chan);
+}
+
+static struct jz4740_dma_desc *to_jz4740_dma_desc(struct virt_dma_desc *vdesc)
+{
+       return container_of(vdesc, struct jz4740_dma_desc, vdesc);
+}
+
+static inline uint32_t jz4740_dma_read(struct jz4740_dma_dev *dmadev,
+       unsigned int reg)
+{
+       return readl(dmadev->base + reg);
+}
+
+static inline void jz4740_dma_write(struct jz4740_dma_dev *dmadev,
+       unsigned reg, uint32_t val)
+{
+       writel(val, dmadev->base + reg);
+}
+
+static inline void jz4740_dma_write_mask(struct jz4740_dma_dev *dmadev,
+       unsigned int reg, uint32_t val, uint32_t mask)
+{
+       uint32_t tmp;
+
+       tmp = jz4740_dma_read(dmadev, reg);
+       tmp &= ~mask;
+       tmp |= val;
+       jz4740_dma_write(dmadev, reg, tmp);
+}
+
+static struct jz4740_dma_desc *jz4740_dma_alloc_desc(unsigned int num_sgs)
+{
+       return kzalloc(sizeof(struct jz4740_dma_desc) +
+               sizeof(struct jz4740_dma_sg) * num_sgs, GFP_ATOMIC);
+}
+
+static enum jz4740_dma_width jz4740_dma_width(enum dma_slave_buswidth width)
+{
+       switch (width) {
+       case DMA_SLAVE_BUSWIDTH_1_BYTE:
+               return JZ4740_DMA_WIDTH_8BIT;
+       case DMA_SLAVE_BUSWIDTH_2_BYTES:
+               return JZ4740_DMA_WIDTH_16BIT;
+       case DMA_SLAVE_BUSWIDTH_4_BYTES:
+               return JZ4740_DMA_WIDTH_32BIT;
+       default:
+               return JZ4740_DMA_WIDTH_32BIT;
+       }
+}
+
+static enum jz4740_dma_transfer_size jz4740_dma_maxburst(u32 maxburst)
+{
+       if (maxburst <= 1)
+               return JZ4740_DMA_TRANSFER_SIZE_1BYTE;
+       else if (maxburst <= 3)
+               return JZ4740_DMA_TRANSFER_SIZE_2BYTE;
+       else if (maxburst <= 15)
+               return JZ4740_DMA_TRANSFER_SIZE_4BYTE;
+       else if (maxburst <= 31)
+               return JZ4740_DMA_TRANSFER_SIZE_16BYTE;
+
+       return JZ4740_DMA_TRANSFER_SIZE_32BYTE;
+}
+
+static int jz4740_dma_slave_config(struct dma_chan *c,
+                                  struct dma_slave_config *config)
+{
+       struct jz4740_dmaengine_chan *chan = to_jz4740_dma_chan(c);
+       struct jz4740_dma_dev *dmadev = jz4740_dma_chan_get_dev(chan);
+       enum jz4740_dma_width src_width;
+       enum jz4740_dma_width dst_width;
+       enum jz4740_dma_transfer_size transfer_size;
+       enum jz4740_dma_flags flags;
+       uint32_t cmd;
+
+       switch (config->direction) {
+       case DMA_MEM_TO_DEV:
+               flags = JZ4740_DMA_SRC_AUTOINC;
+               transfer_size = jz4740_dma_maxburst(config->dst_maxburst);
+               chan->fifo_addr = config->dst_addr;
+               break;
+       case DMA_DEV_TO_MEM:
+               flags = JZ4740_DMA_DST_AUTOINC;
+               transfer_size = jz4740_dma_maxburst(config->src_maxburst);
+               chan->fifo_addr = config->src_addr;
+               break;
+       default:
+               return -EINVAL;
+       }
+
+       src_width = jz4740_dma_width(config->src_addr_width);
+       dst_width = jz4740_dma_width(config->dst_addr_width);
+
+       switch (transfer_size) {
+       case JZ4740_DMA_TRANSFER_SIZE_2BYTE:
+               chan->transfer_shift = 1;
+               break;
+       case JZ4740_DMA_TRANSFER_SIZE_4BYTE:
+               chan->transfer_shift = 2;
+               break;
+       case JZ4740_DMA_TRANSFER_SIZE_16BYTE:
+               chan->transfer_shift = 4;
+               break;
+       case JZ4740_DMA_TRANSFER_SIZE_32BYTE:
+               chan->transfer_shift = 5;
+               break;
+       default:
+               chan->transfer_shift = 0;
+               break;
+       }
+
+       cmd = flags << JZ_DMA_CMD_FLAGS_OFFSET;
+       cmd |= src_width << JZ_DMA_CMD_SRC_WIDTH_OFFSET;
+       cmd |= dst_width << JZ_DMA_CMD_DST_WIDTH_OFFSET;
+       cmd |= transfer_size << JZ_DMA_CMD_TRANSFER_SIZE_OFFSET;
+       cmd |= JZ4740_DMA_MODE_SINGLE << JZ_DMA_CMD_MODE_OFFSET;
+       cmd |= JZ_DMA_CMD_TRANSFER_IRQ_ENABLE;
+
+       jz4740_dma_write(dmadev, JZ_REG_DMA_CMD(chan->id), cmd);
+       jz4740_dma_write(dmadev, JZ_REG_DMA_STATUS_CTRL(chan->id), 0);
+       jz4740_dma_write(dmadev, JZ_REG_DMA_REQ_TYPE(chan->id),
+               config->slave_id);
+
+       return 0;
+}
+
+static int jz4740_dma_terminate_all(struct dma_chan *c)
+{
+       struct jz4740_dmaengine_chan *chan = to_jz4740_dma_chan(c);
+       struct jz4740_dma_dev *dmadev = jz4740_dma_chan_get_dev(chan);
+       unsigned long flags;
+       LIST_HEAD(head);
+
+       spin_lock_irqsave(&chan->vchan.lock, flags);
+       jz4740_dma_write_mask(dmadev, JZ_REG_DMA_STATUS_CTRL(chan->id), 0,
+                       JZ_DMA_STATUS_CTRL_ENABLE);
+       chan->desc = NULL;
+       vchan_get_all_descriptors(&chan->vchan, &head);
+       spin_unlock_irqrestore(&chan->vchan.lock, flags);
+
+       vchan_dma_desc_free_list(&chan->vchan, &head);
+
+       return 0;
+}
+
+static int jz4740_dma_start_transfer(struct jz4740_dmaengine_chan *chan)
+{
+       struct jz4740_dma_dev *dmadev = jz4740_dma_chan_get_dev(chan);
+       dma_addr_t src_addr, dst_addr;
+       struct virt_dma_desc *vdesc;
+       struct jz4740_dma_sg *sg;
+
+       jz4740_dma_write_mask(dmadev, JZ_REG_DMA_STATUS_CTRL(chan->id), 0,
+                       JZ_DMA_STATUS_CTRL_ENABLE);
+
+       if (!chan->desc) {
+               vdesc = vchan_next_desc(&chan->vchan);
+               if (!vdesc)
+                       return 0;
+               chan->desc = to_jz4740_dma_desc(vdesc);
+               chan->next_sg = 0;
+       }
+
+       if (chan->next_sg == chan->desc->num_sgs)
+               chan->next_sg = 0;
+
+       sg = &chan->desc->sg[chan->next_sg];
+
+       if (chan->desc->direction == DMA_MEM_TO_DEV) {
+               src_addr = sg->addr;
+               dst_addr = chan->fifo_addr;
+       } else {
+               src_addr = chan->fifo_addr;
+               dst_addr = sg->addr;
+       }
+       jz4740_dma_write(dmadev, JZ_REG_DMA_SRC_ADDR(chan->id), src_addr);
+       jz4740_dma_write(dmadev, JZ_REG_DMA_DST_ADDR(chan->id), dst_addr);
+       jz4740_dma_write(dmadev, JZ_REG_DMA_TRANSFER_COUNT(chan->id),
+                       sg->len >> chan->transfer_shift);
+
+       chan->next_sg++;
+
+       jz4740_dma_write_mask(dmadev, JZ_REG_DMA_STATUS_CTRL(chan->id),
+                       JZ_DMA_STATUS_CTRL_NO_DESC | JZ_DMA_STATUS_CTRL_ENABLE,
+                       JZ_DMA_STATUS_CTRL_HALT | JZ_DMA_STATUS_CTRL_NO_DESC |
+                       JZ_DMA_STATUS_CTRL_ENABLE);
+
+       jz4740_dma_write_mask(dmadev, JZ_REG_DMA_CTRL,
+                       JZ_DMA_CTRL_ENABLE,
+                       JZ_DMA_CTRL_HALT | JZ_DMA_CTRL_ENABLE);
+
+       return 0;
+}
+
+static void jz4740_dma_chan_irq(struct jz4740_dmaengine_chan *chan)
+{
+       spin_lock(&chan->vchan.lock);
+       if (chan->desc) {
+               if (chan->desc->cyclic) {
+                       vchan_cyclic_callback(&chan->desc->vdesc);
+               } else {
+                       if (chan->next_sg == chan->desc->num_sgs) {
+                               list_del(&chan->desc->vdesc.node);
+                               vchan_cookie_complete(&chan->desc->vdesc);
+                               chan->desc = NULL;
+                       }
+               }
+       }
+       jz4740_dma_start_transfer(chan);
+       spin_unlock(&chan->vchan.lock);
+}
+
+static irqreturn_t jz4740_dma_irq(int irq, void *devid)
+{
+       struct jz4740_dma_dev *dmadev = devid;
+       uint32_t irq_status;
+       unsigned int i;
+
+       irq_status = readl(dmadev->base + JZ_REG_DMA_IRQ);
+
+       for (i = 0; i < 6; ++i) {
+               if (irq_status & (1 << i)) {
+                       jz4740_dma_write_mask(dmadev,
+                               JZ_REG_DMA_STATUS_CTRL(i), 0,
+                               JZ_DMA_STATUS_CTRL_ENABLE |
+                               JZ_DMA_STATUS_CTRL_TRANSFER_DONE);
+
+                       jz4740_dma_chan_irq(&dmadev->chan[i]);
+               }
+       }
+
+       return IRQ_HANDLED;
+}
+
+static void jz4740_dma_issue_pending(struct dma_chan *c)
+{
+       struct jz4740_dmaengine_chan *chan = to_jz4740_dma_chan(c);
+       unsigned long flags;
+
+       spin_lock_irqsave(&chan->vchan.lock, flags);
+       if (vchan_issue_pending(&chan->vchan) && !chan->desc)
+               jz4740_dma_start_transfer(chan);
+       spin_unlock_irqrestore(&chan->vchan.lock, flags);
+}
+
+static struct dma_async_tx_descriptor *jz4740_dma_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 jz4740_dmaengine_chan *chan = to_jz4740_dma_chan(c);
+       struct jz4740_dma_desc *desc;
+       struct scatterlist *sg;
+       unsigned int i;
+
+       desc = jz4740_dma_alloc_desc(sg_len);
+       if (!desc)
+               return NULL;
+
+       for_each_sg(sgl, sg, sg_len, i) {
+               desc->sg[i].addr = sg_dma_address(sg);
+               desc->sg[i].len = sg_dma_len(sg);
+       }
+
+       desc->num_sgs = sg_len;
+       desc->direction = direction;
+       desc->cyclic = false;
+
+       return vchan_tx_prep(&chan->vchan, &desc->vdesc, flags);
+}
+
+static struct dma_async_tx_descriptor *jz4740_dma_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 jz4740_dmaengine_chan *chan = to_jz4740_dma_chan(c);
+       struct jz4740_dma_desc *desc;
+       unsigned int num_periods, i;
+
+       if (buf_len % period_len)
+               return NULL;
+
+       num_periods = buf_len / period_len;
+
+       desc = jz4740_dma_alloc_desc(num_periods);
+       if (!desc)
+               return NULL;
+
+       for (i = 0; i < num_periods; i++) {
+               desc->sg[i].addr = buf_addr;
+               desc->sg[i].len = period_len;
+               buf_addr += period_len;
+       }
+
+       desc->num_sgs = num_periods;
+       desc->direction = direction;
+       desc->cyclic = true;
+
+       return vchan_tx_prep(&chan->vchan, &desc->vdesc, flags);
+}
+
+static size_t jz4740_dma_desc_residue(struct jz4740_dmaengine_chan *chan,
+       struct jz4740_dma_desc *desc, unsigned int next_sg)
+{
+       struct jz4740_dma_dev *dmadev = jz4740_dma_chan_get_dev(chan);
+       unsigned int residue, count;
+       unsigned int i;
+
+       residue = 0;
+
+       for (i = next_sg; i < desc->num_sgs; i++)
+               residue += desc->sg[i].len;
+
+       if (next_sg != 0) {
+               count = jz4740_dma_read(dmadev,
+                       JZ_REG_DMA_TRANSFER_COUNT(chan->id));
+               residue += count << chan->transfer_shift;
+       }
+
+       return residue;
+}
+
+static enum dma_status jz4740_dma_tx_status(struct dma_chan *c,
+       dma_cookie_t cookie, struct dma_tx_state *state)
+{
+       struct jz4740_dmaengine_chan *chan = to_jz4740_dma_chan(c);
+       struct virt_dma_desc *vdesc;
+       enum dma_status status;
+       unsigned long flags;
+
+       status = dma_cookie_status(c, cookie, state);
+       if (status == DMA_COMPLETE || !state)
+               return status;
+
+       spin_lock_irqsave(&chan->vchan.lock, flags);
+       vdesc = vchan_find_desc(&chan->vchan, cookie);
+       if (cookie == chan->desc->vdesc.tx.cookie) {
+               state->residue = jz4740_dma_desc_residue(chan, chan->desc,
+                               chan->next_sg);
+       } else if (vdesc) {
+               state->residue = jz4740_dma_desc_residue(chan,
+                               to_jz4740_dma_desc(vdesc), 0);
+       } else {
+               state->residue = 0;
+       }
+       spin_unlock_irqrestore(&chan->vchan.lock, flags);
+
+       return status;
+}
+
+static void jz4740_dma_free_chan_resources(struct dma_chan *c)
+{
+       vchan_free_chan_resources(to_virt_chan(c));
+}
+
+static void jz4740_dma_desc_free(struct virt_dma_desc *vdesc)
+{
+       kfree(container_of(vdesc, struct jz4740_dma_desc, vdesc));
+}
+
+#define JZ4740_DMA_BUSWIDTHS (BIT(DMA_SLAVE_BUSWIDTH_1_BYTE) | \
+       BIT(DMA_SLAVE_BUSWIDTH_2_BYTES) | BIT(DMA_SLAVE_BUSWIDTH_4_BYTES))
+
+static int jz4740_dma_probe(struct platform_device *pdev)
+{
+       struct jz4740_dmaengine_chan *chan;
+       struct jz4740_dma_dev *dmadev;
+       struct dma_device *dd;
+       unsigned int i;
+       struct resource *res;
+       int ret;
+       int irq;
+
+       dmadev = devm_kzalloc(&pdev->dev, sizeof(*dmadev), GFP_KERNEL);
+       if (!dmadev)
+               return -EINVAL;
+
+       dd = &dmadev->ddev;
+
+       res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+       dmadev->base = devm_ioremap_resource(&pdev->dev, res);
+       if (IS_ERR(dmadev->base))
+               return PTR_ERR(dmadev->base);
+
+       dmadev->clk = clk_get(&pdev->dev, "dma");
+       if (IS_ERR(dmadev->clk))
+               return PTR_ERR(dmadev->clk);
+
+       clk_prepare_enable(dmadev->clk);
+
+       dma_cap_set(DMA_SLAVE, dd->cap_mask);
+       dma_cap_set(DMA_CYCLIC, dd->cap_mask);
+       dd->device_free_chan_resources = jz4740_dma_free_chan_resources;
+       dd->device_tx_status = jz4740_dma_tx_status;
+       dd->device_issue_pending = jz4740_dma_issue_pending;
+       dd->device_prep_slave_sg = jz4740_dma_prep_slave_sg;
+       dd->device_prep_dma_cyclic = jz4740_dma_prep_dma_cyclic;
+       dd->device_config = jz4740_dma_slave_config;
+       dd->device_terminate_all = jz4740_dma_terminate_all;
+       dd->src_addr_widths = JZ4740_DMA_BUSWIDTHS;
+       dd->dst_addr_widths = JZ4740_DMA_BUSWIDTHS;
+       dd->directions = BIT(DMA_DEV_TO_MEM) | BIT(DMA_MEM_TO_DEV);
+       dd->residue_granularity = DMA_RESIDUE_GRANULARITY_BURST;
+       dd->dev = &pdev->dev;
+       INIT_LIST_HEAD(&dd->channels);
+
+       for (i = 0; i < JZ_DMA_NR_CHANS; i++) {
+               chan = &dmadev->chan[i];
+               chan->id = i;
+               chan->vchan.desc_free = jz4740_dma_desc_free;
+               vchan_init(&chan->vchan, dd);
+       }
+
+       ret = dma_async_device_register(dd);
+       if (ret)
+               return ret;
+
+       irq = platform_get_irq(pdev, 0);
+       ret = request_irq(irq, jz4740_dma_irq, 0, dev_name(&pdev->dev), dmadev);
+       if (ret)
+               goto err_unregister;
+
+       platform_set_drvdata(pdev, dmadev);
+
+       return 0;
+
+err_unregister:
+       dma_async_device_unregister(dd);
+       return ret;
+}
+
+static int jz4740_dma_remove(struct platform_device *pdev)
+{
+       struct jz4740_dma_dev *dmadev = platform_get_drvdata(pdev);
+       int irq = platform_get_irq(pdev, 0);
+
+       free_irq(irq, dmadev);
+       dma_async_device_unregister(&dmadev->ddev);
+       clk_disable_unprepare(dmadev->clk);
+
+       return 0;
+}
+
+static struct platform_driver jz4740_dma_driver = {
+       .probe = jz4740_dma_probe,
+       .remove = jz4740_dma_remove,
+       .driver = {
+               .name = "jz4740-dma",
+       },
+};
+module_platform_driver(jz4740_dma_driver);
+
+MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
+MODULE_DESCRIPTION("JZ4740 DMA driver");
+MODULE_LICENSE("GPL v2");