Adding upstream version 6.1.76.upstream/6.1.76

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

1 files changed, 845 insertions, 0 deletions

diff --git a/drivers/dma/mxs-dma.c b/drivers/dma/mxs-dma.c
new file mode 100644
index 000000000..dc147cc24
--- /dev/null
+++ b/drivers/dma/mxs-dma.c
@@ -0,0 +1,845 @@
+// SPDX-License-Identifier: GPL-2.0
+//
+// Copyright 2011 Freescale Semiconductor, Inc. All Rights Reserved.
+//
+// Refer to drivers/dma/imx-sdma.c
+
+#include <linux/init.h>
+#include <linux/types.h>
+#include <linux/mm.h>
+#include <linux/interrupt.h>
+#include <linux/clk.h>
+#include <linux/wait.h>
+#include <linux/sched.h>
+#include <linux/semaphore.h>
+#include <linux/device.h>
+#include <linux/dma-mapping.h>
+#include <linux/slab.h>
+#include <linux/platform_device.h>
+#include <linux/dmaengine.h>
+#include <linux/delay.h>
+#include <linux/module.h>
+#include <linux/stmp_device.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/of_dma.h>
+#include <linux/list.h>
+#include <linux/dma/mxs-dma.h>
+
+#include <asm/irq.h>
+
+#include "dmaengine.h"
+
+/*
+ * NOTE: The term "PIO" throughout the mxs-dma implementation means
+ * PIO mode of mxs apbh-dma and apbx-dma.  With this working mode,
+ * dma can program the controller registers of peripheral devices.
+ */
+
+#define dma_is_apbh(mxs_dma)	((mxs_dma)->type == MXS_DMA_APBH)
+#define apbh_is_old(mxs_dma)	((mxs_dma)->dev_id == IMX23_DMA)
+
+#define HW_APBHX_CTRL0				0x000
+#define BM_APBH_CTRL0_APB_BURST8_EN		(1 << 29)
+#define BM_APBH_CTRL0_APB_BURST_EN		(1 << 28)
+#define BP_APBH_CTRL0_RESET_CHANNEL		16
+#define HW_APBHX_CTRL1				0x010
+#define HW_APBHX_CTRL2				0x020
+#define HW_APBHX_CHANNEL_CTRL			0x030
+#define BP_APBHX_CHANNEL_CTRL_RESET_CHANNEL	16
+/*
+ * The offset of NXTCMDAR register is different per both dma type and version,
+ * while stride for each channel is all the same 0x70.
+ */
+#define HW_APBHX_CHn_NXTCMDAR(d, n) \
+	(((dma_is_apbh(d) && apbh_is_old(d)) ? 0x050 : 0x110) + (n) * 0x70)
+#define HW_APBHX_CHn_SEMA(d, n) \
+	(((dma_is_apbh(d) && apbh_is_old(d)) ? 0x080 : 0x140) + (n) * 0x70)
+#define HW_APBHX_CHn_BAR(d, n) \
+	(((dma_is_apbh(d) && apbh_is_old(d)) ? 0x070 : 0x130) + (n) * 0x70)
+#define HW_APBX_CHn_DEBUG1(d, n) (0x150 + (n) * 0x70)
+
+/*
+ * ccw bits definitions
+ *
+ * COMMAND:		0..1	(2)
+ * CHAIN:		2	(1)
+ * IRQ:			3	(1)
+ * NAND_LOCK:		4	(1) - not implemented
+ * NAND_WAIT4READY:	5	(1) - not implemented
+ * DEC_SEM:		6	(1)
+ * WAIT4END:		7	(1)
+ * HALT_ON_TERMINATE:	8	(1)
+ * TERMINATE_FLUSH:	9	(1)
+ * RESERVED:		10..11	(2)
+ * PIO_NUM:		12..15	(4)
+ */
+#define BP_CCW_COMMAND		0
+#define BM_CCW_COMMAND		(3 << 0)
+#define CCW_CHAIN		(1 << 2)
+#define CCW_IRQ			(1 << 3)
+#define CCW_WAIT4RDY		(1 << 5)
+#define CCW_DEC_SEM		(1 << 6)
+#define CCW_WAIT4END		(1 << 7)
+#define CCW_HALT_ON_TERM	(1 << 8)
+#define CCW_TERM_FLUSH		(1 << 9)
+#define BP_CCW_PIO_NUM		12
+#define BM_CCW_PIO_NUM		(0xf << 12)
+
+#define BF_CCW(value, field)	(((value) << BP_CCW_##field) & BM_CCW_##field)
+
+#define MXS_DMA_CMD_NO_XFER	0
+#define MXS_DMA_CMD_WRITE	1
+#define MXS_DMA_CMD_READ	2
+#define MXS_DMA_CMD_DMA_SENSE	3	/* not implemented */
+
+struct mxs_dma_ccw {
+	u32		next;
+	u16		bits;
+	u16		xfer_bytes;
+#define MAX_XFER_BYTES	0xff00
+	u32		bufaddr;
+#define MXS_PIO_WORDS	16
+	u32		pio_words[MXS_PIO_WORDS];
+};
+
+#define CCW_BLOCK_SIZE	(4 * PAGE_SIZE)
+#define NUM_CCW	(int)(CCW_BLOCK_SIZE / sizeof(struct mxs_dma_ccw))
+
+struct mxs_dma_chan {
+	struct mxs_dma_engine		*mxs_dma;
+	struct dma_chan			chan;
+	struct dma_async_tx_descriptor	desc;
+	struct tasklet_struct		tasklet;
+	unsigned int			chan_irq;
+	struct mxs_dma_ccw		*ccw;
+	dma_addr_t			ccw_phys;
+	int				desc_count;
+	enum dma_status			status;
+	unsigned int			flags;
+	bool				reset;
+#define MXS_DMA_SG_LOOP			(1 << 0)
+#define MXS_DMA_USE_SEMAPHORE		(1 << 1)
+};
+
+#define MXS_DMA_CHANNELS		16
+#define MXS_DMA_CHANNELS_MASK		0xffff
+
+enum mxs_dma_devtype {
+	MXS_DMA_APBH,
+	MXS_DMA_APBX,
+};
+
+enum mxs_dma_id {
+	IMX23_DMA,
+	IMX28_DMA,
+};
+
+struct mxs_dma_engine {
+	enum mxs_dma_id			dev_id;
+	enum mxs_dma_devtype		type;
+	void __iomem			*base;
+	struct clk			*clk;
+	struct dma_device		dma_device;
+	struct mxs_dma_chan		mxs_chans[MXS_DMA_CHANNELS];
+	struct platform_device		*pdev;
+	unsigned int			nr_channels;
+};
+
+struct mxs_dma_type {
+	enum mxs_dma_id id;
+	enum mxs_dma_devtype type;
+};
+
+static struct mxs_dma_type mxs_dma_types[] = {
+	{
+		.id = IMX23_DMA,
+		.type = MXS_DMA_APBH,
+	}, {
+		.id = IMX23_DMA,
+		.type = MXS_DMA_APBX,
+	}, {
+		.id = IMX28_DMA,
+		.type = MXS_DMA_APBH,
+	}, {
+		.id = IMX28_DMA,
+		.type = MXS_DMA_APBX,
+	}
+};
+
+static const struct of_device_id mxs_dma_dt_ids[] = {
+	{ .compatible = "fsl,imx23-dma-apbh", .data = &mxs_dma_types[0], },
+	{ .compatible = "fsl,imx23-dma-apbx", .data = &mxs_dma_types[1], },
+	{ .compatible = "fsl,imx28-dma-apbh", .data = &mxs_dma_types[2], },
+	{ .compatible = "fsl,imx28-dma-apbx", .data = &mxs_dma_types[3], },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, mxs_dma_dt_ids);
+
+static struct mxs_dma_chan *to_mxs_dma_chan(struct dma_chan *chan)
+{
+	return container_of(chan, struct mxs_dma_chan, chan);
+}
+
+static void mxs_dma_reset_chan(struct dma_chan *chan)
+{
+	struct mxs_dma_chan *mxs_chan = to_mxs_dma_chan(chan);
+	struct mxs_dma_engine *mxs_dma = mxs_chan->mxs_dma;
+	int chan_id = mxs_chan->chan.chan_id;
+
+	/*
+	 * mxs dma channel resets can cause a channel stall. To recover from a
+	 * channel stall, we have to reset the whole DMA engine. To avoid this,
+	 * we use cyclic DMA with semaphores, that are enhanced in
+	 * mxs_dma_int_handler. To reset the channel, we can simply stop writing
+	 * into the semaphore counter.
+	 */
+	if (mxs_chan->flags & MXS_DMA_USE_SEMAPHORE &&
+			mxs_chan->flags & MXS_DMA_SG_LOOP) {
+		mxs_chan->reset = true;
+	} else if (dma_is_apbh(mxs_dma) && apbh_is_old(mxs_dma)) {
+		writel(1 << (chan_id + BP_APBH_CTRL0_RESET_CHANNEL),
+			mxs_dma->base + HW_APBHX_CTRL0 + STMP_OFFSET_REG_SET);
+	} else {
+		unsigned long elapsed = 0;
+		const unsigned long max_wait = 50000; /* 50ms */
+		void __iomem *reg_dbg1 = mxs_dma->base +
+				HW_APBX_CHn_DEBUG1(mxs_dma, chan_id);
+
+		/*
+		 * On i.MX28 APBX, the DMA channel can stop working if we reset
+		 * the channel while it is in READ_FLUSH (0x08) state.
+		 * We wait here until we leave the state. Then we trigger the
+		 * reset. Waiting a maximum of 50ms, the kernel shouldn't crash
+		 * because of this.
+		 */
+		while ((readl(reg_dbg1) & 0xf) == 0x8 && elapsed < max_wait) {
+			udelay(100);
+			elapsed += 100;
+		}
+
+		if (elapsed >= max_wait)
+			dev_err(&mxs_chan->mxs_dma->pdev->dev,
+					"Failed waiting for the DMA channel %d to leave state READ_FLUSH, trying to reset channel in READ_FLUSH state now\n",
+					chan_id);
+
+		writel(1 << (chan_id + BP_APBHX_CHANNEL_CTRL_RESET_CHANNEL),
+			mxs_dma->base + HW_APBHX_CHANNEL_CTRL + STMP_OFFSET_REG_SET);
+	}
+
+	mxs_chan->status = DMA_COMPLETE;
+}
+
+static void mxs_dma_enable_chan(struct dma_chan *chan)
+{
+	struct mxs_dma_chan *mxs_chan = to_mxs_dma_chan(chan);
+	struct mxs_dma_engine *mxs_dma = mxs_chan->mxs_dma;
+	int chan_id = mxs_chan->chan.chan_id;
+
+	/* set cmd_addr up */
+	writel(mxs_chan->ccw_phys,
+		mxs_dma->base + HW_APBHX_CHn_NXTCMDAR(mxs_dma, chan_id));
+
+	/* write 1 to SEMA to kick off the channel */
+	if (mxs_chan->flags & MXS_DMA_USE_SEMAPHORE &&
+			mxs_chan->flags & MXS_DMA_SG_LOOP) {
+		/* A cyclic DMA consists of at least 2 segments, so initialize
+		 * the semaphore with 2 so we have enough time to add 1 to the
+		 * semaphore if we need to */
+		writel(2, mxs_dma->base + HW_APBHX_CHn_SEMA(mxs_dma, chan_id));
+	} else {
+		writel(1, mxs_dma->base + HW_APBHX_CHn_SEMA(mxs_dma, chan_id));
+	}
+	mxs_chan->reset = false;
+}
+
+static void mxs_dma_disable_chan(struct dma_chan *chan)
+{
+	struct mxs_dma_chan *mxs_chan = to_mxs_dma_chan(chan);
+
+	mxs_chan->status = DMA_COMPLETE;
+}
+
+static int mxs_dma_pause_chan(struct dma_chan *chan)
+{
+	struct mxs_dma_chan *mxs_chan = to_mxs_dma_chan(chan);
+	struct mxs_dma_engine *mxs_dma = mxs_chan->mxs_dma;
+	int chan_id = mxs_chan->chan.chan_id;
+
+	/* freeze the channel */
+	if (dma_is_apbh(mxs_dma) && apbh_is_old(mxs_dma))
+		writel(1 << chan_id,
+			mxs_dma->base + HW_APBHX_CTRL0 + STMP_OFFSET_REG_SET);
+	else
+		writel(1 << chan_id,
+			mxs_dma->base + HW_APBHX_CHANNEL_CTRL + STMP_OFFSET_REG_SET);
+
+	mxs_chan->status = DMA_PAUSED;
+	return 0;
+}
+
+static int mxs_dma_resume_chan(struct dma_chan *chan)
+{
+	struct mxs_dma_chan *mxs_chan = to_mxs_dma_chan(chan);
+	struct mxs_dma_engine *mxs_dma = mxs_chan->mxs_dma;
+	int chan_id = mxs_chan->chan.chan_id;
+
+	/* unfreeze the channel */
+	if (dma_is_apbh(mxs_dma) && apbh_is_old(mxs_dma))
+		writel(1 << chan_id,
+			mxs_dma->base + HW_APBHX_CTRL0 + STMP_OFFSET_REG_CLR);
+	else
+		writel(1 << chan_id,
+			mxs_dma->base + HW_APBHX_CHANNEL_CTRL + STMP_OFFSET_REG_CLR);
+
+	mxs_chan->status = DMA_IN_PROGRESS;
+	return 0;
+}
+
+static dma_cookie_t mxs_dma_tx_submit(struct dma_async_tx_descriptor *tx)
+{
+	return dma_cookie_assign(tx);
+}
+
+static void mxs_dma_tasklet(struct tasklet_struct *t)
+{
+	struct mxs_dma_chan *mxs_chan = from_tasklet(mxs_chan, t, tasklet);
+
+	dmaengine_desc_get_callback_invoke(&mxs_chan->desc, NULL);
+}
+
+static int mxs_dma_irq_to_chan(struct mxs_dma_engine *mxs_dma, int irq)
+{
+	int i;
+
+	for (i = 0; i != mxs_dma->nr_channels; ++i)
+		if (mxs_dma->mxs_chans[i].chan_irq == irq)
+			return i;
+
+	return -EINVAL;
+}
+
+static irqreturn_t mxs_dma_int_handler(int irq, void *dev_id)
+{
+	struct mxs_dma_engine *mxs_dma = dev_id;
+	struct mxs_dma_chan *mxs_chan;
+	u32 completed;
+	u32 err;
+	int chan = mxs_dma_irq_to_chan(mxs_dma, irq);
+
+	if (chan < 0)
+		return IRQ_NONE;
+
+	/* completion status */
+	completed = readl(mxs_dma->base + HW_APBHX_CTRL1);
+	completed = (completed >> chan) & 0x1;
+
+	/* Clear interrupt */
+	writel((1 << chan),
+			mxs_dma->base + HW_APBHX_CTRL1 + STMP_OFFSET_REG_CLR);
+
+	/* error status */
+	err = readl(mxs_dma->base + HW_APBHX_CTRL2);
+	err &= (1 << (MXS_DMA_CHANNELS + chan)) | (1 << chan);
+
+	/*
+	 * error status bit is in the upper 16 bits, error irq bit in the lower
+	 * 16 bits. We transform it into a simpler error code:
+	 * err: 0x00 = no error, 0x01 = TERMINATION, 0x02 = BUS_ERROR
+	 */
+	err = (err >> (MXS_DMA_CHANNELS + chan)) + (err >> chan);
+
+	/* Clear error irq */
+	writel((1 << chan),
+			mxs_dma->base + HW_APBHX_CTRL2 + STMP_OFFSET_REG_CLR);
+
+	/*
+	 * When both completion and error of termination bits set at the
+	 * same time, we do not take it as an error.  IOW, it only becomes
+	 * an error we need to handle here in case of either it's a bus
+	 * error or a termination error with no completion. 0x01 is termination
+	 * error, so we can subtract err & completed to get the real error case.
+	 */
+	err -= err & completed;
+
+	mxs_chan = &mxs_dma->mxs_chans[chan];
+
+	if (err) {
+		dev_dbg(mxs_dma->dma_device.dev,
+			"%s: error in channel %d\n", __func__,
+			chan);
+		mxs_chan->status = DMA_ERROR;
+		mxs_dma_reset_chan(&mxs_chan->chan);
+	} else if (mxs_chan->status != DMA_COMPLETE) {
+		if (mxs_chan->flags & MXS_DMA_SG_LOOP) {
+			mxs_chan->status = DMA_IN_PROGRESS;
+			if (mxs_chan->flags & MXS_DMA_USE_SEMAPHORE)
+				writel(1, mxs_dma->base +
+					HW_APBHX_CHn_SEMA(mxs_dma, chan));
+		} else {
+			mxs_chan->status = DMA_COMPLETE;
+		}
+	}
+
+	if (mxs_chan->status == DMA_COMPLETE) {
+		if (mxs_chan->reset)
+			return IRQ_HANDLED;
+		dma_cookie_complete(&mxs_chan->desc);
+	}
+
+	/* schedule tasklet on this channel */
+	tasklet_schedule(&mxs_chan->tasklet);
+
+	return IRQ_HANDLED;
+}
+
+static int mxs_dma_alloc_chan_resources(struct dma_chan *chan)
+{
+	struct mxs_dma_chan *mxs_chan = to_mxs_dma_chan(chan);
+	struct mxs_dma_engine *mxs_dma = mxs_chan->mxs_dma;
+	int ret;
+
+	mxs_chan->ccw = dma_alloc_coherent(mxs_dma->dma_device.dev,
+					   CCW_BLOCK_SIZE,
+					   &mxs_chan->ccw_phys, GFP_KERNEL);
+	if (!mxs_chan->ccw) {
+		ret = -ENOMEM;
+		goto err_alloc;
+	}
+
+	ret = request_irq(mxs_chan->chan_irq, mxs_dma_int_handler,
+			  0, "mxs-dma", mxs_dma);
+	if (ret)
+		goto err_irq;
+
+	ret = clk_prepare_enable(mxs_dma->clk);
+	if (ret)
+		goto err_clk;
+
+	mxs_dma_reset_chan(chan);
+
+	dma_async_tx_descriptor_init(&mxs_chan->desc, chan);
+	mxs_chan->desc.tx_submit = mxs_dma_tx_submit;
+
+	/* the descriptor is ready */
+	async_tx_ack(&mxs_chan->desc);
+
+	return 0;
+
+err_clk:
+	free_irq(mxs_chan->chan_irq, mxs_dma);
+err_irq:
+	dma_free_coherent(mxs_dma->dma_device.dev, CCW_BLOCK_SIZE,
+			mxs_chan->ccw, mxs_chan->ccw_phys);
+err_alloc:
+	return ret;
+}
+
+static void mxs_dma_free_chan_resources(struct dma_chan *chan)
+{
+	struct mxs_dma_chan *mxs_chan = to_mxs_dma_chan(chan);
+	struct mxs_dma_engine *mxs_dma = mxs_chan->mxs_dma;
+
+	mxs_dma_disable_chan(chan);
+
+	free_irq(mxs_chan->chan_irq, mxs_dma);
+
+	dma_free_coherent(mxs_dma->dma_device.dev, CCW_BLOCK_SIZE,
+			mxs_chan->ccw, mxs_chan->ccw_phys);
+
+	clk_disable_unprepare(mxs_dma->clk);
+}
+
+/*
+ * How to use the flags for ->device_prep_slave_sg() :
+ *    [1] If there is only one DMA command in the DMA chain, the code should be:
+ *            ......
+ *            ->device_prep_slave_sg(DMA_CTRL_ACK);
+ *            ......
+ *    [2] If there are two DMA commands in the DMA chain, the code should be
+ *            ......
+ *            ->device_prep_slave_sg(0);
+ *            ......
+ *            ->device_prep_slave_sg(DMA_CTRL_ACK);
+ *            ......
+ *    [3] If there are more than two DMA commands in the DMA chain, the code
+ *        should be:
+ *            ......
+ *            ->device_prep_slave_sg(0);                                // First
+ *            ......
+ *            ->device_prep_slave_sg(DMA_CTRL_ACK]);
+ *            ......
+ *            ->device_prep_slave_sg(DMA_CTRL_ACK); // Last
+ *            ......
+ */
+static struct dma_async_tx_descriptor *mxs_dma_prep_slave_sg(
+		struct dma_chan *chan, struct scatterlist *sgl,
+		unsigned int sg_len, enum dma_transfer_direction direction,
+		unsigned long flags, void *context)
+{
+	struct mxs_dma_chan *mxs_chan = to_mxs_dma_chan(chan);
+	struct mxs_dma_engine *mxs_dma = mxs_chan->mxs_dma;
+	struct mxs_dma_ccw *ccw;
+	struct scatterlist *sg;
+	u32 i, j;
+	u32 *pio;
+	int idx = 0;
+
+	if (mxs_chan->status == DMA_IN_PROGRESS)
+		idx = mxs_chan->desc_count;
+
+	if (sg_len + idx > NUM_CCW) {
+		dev_err(mxs_dma->dma_device.dev,
+				"maximum number of sg exceeded: %d > %d\n",
+				sg_len, NUM_CCW);
+		goto err_out;
+	}
+
+	mxs_chan->status = DMA_IN_PROGRESS;
+	mxs_chan->flags = 0;
+
+	/*
+	 * If the sg is prepared with append flag set, the sg
+	 * will be appended to the last prepared sg.
+	 */
+	if (idx) {
+		BUG_ON(idx < 1);
+		ccw = &mxs_chan->ccw[idx - 1];
+		ccw->next = mxs_chan->ccw_phys + sizeof(*ccw) * idx;
+		ccw->bits |= CCW_CHAIN;
+		ccw->bits &= ~CCW_IRQ;
+		ccw->bits &= ~CCW_DEC_SEM;
+	} else {
+		idx = 0;
+	}
+
+	if (direction == DMA_TRANS_NONE) {
+		ccw = &mxs_chan->ccw[idx++];
+		pio = (u32 *) sgl;
+
+		for (j = 0; j < sg_len;)
+			ccw->pio_words[j++] = *pio++;
+
+		ccw->bits = 0;
+		ccw->bits |= CCW_IRQ;
+		ccw->bits |= CCW_DEC_SEM;
+		if (flags & MXS_DMA_CTRL_WAIT4END)
+			ccw->bits |= CCW_WAIT4END;
+		ccw->bits |= CCW_HALT_ON_TERM;
+		ccw->bits |= CCW_TERM_FLUSH;
+		ccw->bits |= BF_CCW(sg_len, PIO_NUM);
+		ccw->bits |= BF_CCW(MXS_DMA_CMD_NO_XFER, COMMAND);
+		if (flags & MXS_DMA_CTRL_WAIT4RDY)
+			ccw->bits |= CCW_WAIT4RDY;
+	} else {
+		for_each_sg(sgl, sg, sg_len, i) {
+			if (sg_dma_len(sg) > MAX_XFER_BYTES) {
+				dev_err(mxs_dma->dma_device.dev, "maximum bytes for sg entry exceeded: %d > %d\n",
+						sg_dma_len(sg), MAX_XFER_BYTES);
+				goto err_out;
+			}
+
+			ccw = &mxs_chan->ccw[idx++];
+
+			ccw->next = mxs_chan->ccw_phys + sizeof(*ccw) * idx;
+			ccw->bufaddr = sg->dma_address;
+			ccw->xfer_bytes = sg_dma_len(sg);
+
+			ccw->bits = 0;
+			ccw->bits |= CCW_CHAIN;
+			ccw->bits |= CCW_HALT_ON_TERM;
+			ccw->bits |= CCW_TERM_FLUSH;
+			ccw->bits |= BF_CCW(direction == DMA_DEV_TO_MEM ?
+					MXS_DMA_CMD_WRITE : MXS_DMA_CMD_READ,
+					COMMAND);
+
+			if (i + 1 == sg_len) {
+				ccw->bits &= ~CCW_CHAIN;
+				ccw->bits |= CCW_IRQ;
+				ccw->bits |= CCW_DEC_SEM;
+				if (flags & MXS_DMA_CTRL_WAIT4END)
+					ccw->bits |= CCW_WAIT4END;
+			}
+		}
+	}
+	mxs_chan->desc_count = idx;
+
+	return &mxs_chan->desc;
+
+err_out:
+	mxs_chan->status = DMA_ERROR;
+	return NULL;
+}
+
+static struct dma_async_tx_descriptor *mxs_dma_prep_dma_cyclic(
+		struct dma_chan *chan, dma_addr_t dma_addr, size_t buf_len,
+		size_t period_len, enum dma_transfer_direction direction,
+		unsigned long flags)
+{
+	struct mxs_dma_chan *mxs_chan = to_mxs_dma_chan(chan);
+	struct mxs_dma_engine *mxs_dma = mxs_chan->mxs_dma;
+	u32 num_periods = buf_len / period_len;
+	u32 i = 0, buf = 0;
+
+	if (mxs_chan->status == DMA_IN_PROGRESS)
+		return NULL;
+
+	mxs_chan->status = DMA_IN_PROGRESS;
+	mxs_chan->flags |= MXS_DMA_SG_LOOP;
+	mxs_chan->flags |= MXS_DMA_USE_SEMAPHORE;
+
+	if (num_periods > NUM_CCW) {
+		dev_err(mxs_dma->dma_device.dev,
+				"maximum number of sg exceeded: %d > %d\n",
+				num_periods, NUM_CCW);
+		goto err_out;
+	}
+
+	if (period_len > MAX_XFER_BYTES) {
+		dev_err(mxs_dma->dma_device.dev,
+				"maximum period size exceeded: %zu > %d\n",
+				period_len, MAX_XFER_BYTES);
+		goto err_out;
+	}
+
+	while (buf < buf_len) {
+		struct mxs_dma_ccw *ccw = &mxs_chan->ccw[i];
+
+		if (i + 1 == num_periods)
+			ccw->next = mxs_chan->ccw_phys;
+		else
+			ccw->next = mxs_chan->ccw_phys + sizeof(*ccw) * (i + 1);
+
+		ccw->bufaddr = dma_addr;
+		ccw->xfer_bytes = period_len;
+
+		ccw->bits = 0;
+		ccw->bits |= CCW_CHAIN;
+		ccw->bits |= CCW_IRQ;
+		ccw->bits |= CCW_HALT_ON_TERM;
+		ccw->bits |= CCW_TERM_FLUSH;
+		ccw->bits |= CCW_DEC_SEM;
+		ccw->bits |= BF_CCW(direction == DMA_DEV_TO_MEM ?
+				MXS_DMA_CMD_WRITE : MXS_DMA_CMD_READ, COMMAND);
+
+		dma_addr += period_len;
+		buf += period_len;
+
+		i++;
+	}
+	mxs_chan->desc_count = i;
+
+	return &mxs_chan->desc;
+
+err_out:
+	mxs_chan->status = DMA_ERROR;
+	return NULL;
+}
+
+static int mxs_dma_terminate_all(struct dma_chan *chan)
+{
+	mxs_dma_reset_chan(chan);
+	mxs_dma_disable_chan(chan);
+
+	return 0;
+}
+
+static enum dma_status mxs_dma_tx_status(struct dma_chan *chan,
+			dma_cookie_t cookie, struct dma_tx_state *txstate)
+{
+	struct mxs_dma_chan *mxs_chan = to_mxs_dma_chan(chan);
+	struct mxs_dma_engine *mxs_dma = mxs_chan->mxs_dma;
+	u32 residue = 0;
+
+	if (mxs_chan->status == DMA_IN_PROGRESS &&
+			mxs_chan->flags & MXS_DMA_SG_LOOP) {
+		struct mxs_dma_ccw *last_ccw;
+		u32 bar;
+
+		last_ccw = &mxs_chan->ccw[mxs_chan->desc_count - 1];
+		residue = last_ccw->xfer_bytes + last_ccw->bufaddr;
+
+		bar = readl(mxs_dma->base +
+				HW_APBHX_CHn_BAR(mxs_dma, chan->chan_id));
+		residue -= bar;
+	}
+
+	dma_set_tx_state(txstate, chan->completed_cookie, chan->cookie,
+			residue);
+
+	return mxs_chan->status;
+}
+
+static int mxs_dma_init(struct mxs_dma_engine *mxs_dma)
+{
+	int ret;
+
+	ret = clk_prepare_enable(mxs_dma->clk);
+	if (ret)
+		return ret;
+
+	ret = stmp_reset_block(mxs_dma->base);
+	if (ret)
+		goto err_out;
+
+	/* enable apbh burst */
+	if (dma_is_apbh(mxs_dma)) {
+		writel(BM_APBH_CTRL0_APB_BURST_EN,
+			mxs_dma->base + HW_APBHX_CTRL0 + STMP_OFFSET_REG_SET);
+		writel(BM_APBH_CTRL0_APB_BURST8_EN,
+			mxs_dma->base + HW_APBHX_CTRL0 + STMP_OFFSET_REG_SET);
+	}
+
+	/* enable irq for all the channels */
+	writel(MXS_DMA_CHANNELS_MASK << MXS_DMA_CHANNELS,
+		mxs_dma->base + HW_APBHX_CTRL1 + STMP_OFFSET_REG_SET);
+
+err_out:
+	clk_disable_unprepare(mxs_dma->clk);
+	return ret;
+}
+
+struct mxs_dma_filter_param {
+	unsigned int chan_id;
+};
+
+static bool mxs_dma_filter_fn(struct dma_chan *chan, void *fn_param)
+{
+	struct mxs_dma_filter_param *param = fn_param;
+	struct mxs_dma_chan *mxs_chan = to_mxs_dma_chan(chan);
+	struct mxs_dma_engine *mxs_dma = mxs_chan->mxs_dma;
+	int chan_irq;
+
+	if (chan->chan_id != param->chan_id)
+		return false;
+
+	chan_irq = platform_get_irq(mxs_dma->pdev, param->chan_id);
+	if (chan_irq < 0)
+		return false;
+
+	mxs_chan->chan_irq = chan_irq;
+
+	return true;
+}
+
+static struct dma_chan *mxs_dma_xlate(struct of_phandle_args *dma_spec,
+			       struct of_dma *ofdma)
+{
+	struct mxs_dma_engine *mxs_dma = ofdma->of_dma_data;
+	dma_cap_mask_t mask = mxs_dma->dma_device.cap_mask;
+	struct mxs_dma_filter_param param;
+
+	if (dma_spec->args_count != 1)
+		return NULL;
+
+	param.chan_id = dma_spec->args[0];
+
+	if (param.chan_id >= mxs_dma->nr_channels)
+		return NULL;
+
+	return __dma_request_channel(&mask, mxs_dma_filter_fn, &param,
+				     ofdma->of_node);
+}
+
+static int mxs_dma_probe(struct platform_device *pdev)
+{
+	struct device_node *np = pdev->dev.of_node;
+	const struct mxs_dma_type *dma_type;
+	struct mxs_dma_engine *mxs_dma;
+	struct resource *iores;
+	int ret, i;
+
+	mxs_dma = devm_kzalloc(&pdev->dev, sizeof(*mxs_dma), GFP_KERNEL);
+	if (!mxs_dma)
+		return -ENOMEM;
+
+	ret = of_property_read_u32(np, "dma-channels", &mxs_dma->nr_channels);
+	if (ret) {
+		dev_err(&pdev->dev, "failed to read dma-channels\n");
+		return ret;
+	}
+
+	dma_type = (struct mxs_dma_type *)of_device_get_match_data(&pdev->dev);
+	mxs_dma->type = dma_type->type;
+	mxs_dma->dev_id = dma_type->id;
+
+	iores = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	mxs_dma->base = devm_ioremap_resource(&pdev->dev, iores);
+	if (IS_ERR(mxs_dma->base))
+		return PTR_ERR(mxs_dma->base);
+
+	mxs_dma->clk = devm_clk_get(&pdev->dev, NULL);
+	if (IS_ERR(mxs_dma->clk))
+		return PTR_ERR(mxs_dma->clk);
+
+	dma_cap_set(DMA_SLAVE, mxs_dma->dma_device.cap_mask);
+	dma_cap_set(DMA_CYCLIC, mxs_dma->dma_device.cap_mask);
+
+	INIT_LIST_HEAD(&mxs_dma->dma_device.channels);
+
+	/* Initialize channel parameters */
+	for (i = 0; i < MXS_DMA_CHANNELS; i++) {
+		struct mxs_dma_chan *mxs_chan = &mxs_dma->mxs_chans[i];
+
+		mxs_chan->mxs_dma = mxs_dma;
+		mxs_chan->chan.device = &mxs_dma->dma_device;
+		dma_cookie_init(&mxs_chan->chan);
+
+		tasklet_setup(&mxs_chan->tasklet, mxs_dma_tasklet);
+
+
+		/* Add the channel to mxs_chan list */
+		list_add_tail(&mxs_chan->chan.device_node,
+			&mxs_dma->dma_device.channels);
+	}
+
+	ret = mxs_dma_init(mxs_dma);
+	if (ret)
+		return ret;
+
+	mxs_dma->pdev = pdev;
+	mxs_dma->dma_device.dev = &pdev->dev;
+
+	/* mxs_dma gets 65535 bytes maximum sg size */
+	dma_set_max_seg_size(mxs_dma->dma_device.dev, MAX_XFER_BYTES);
+
+	mxs_dma->dma_device.device_alloc_chan_resources = mxs_dma_alloc_chan_resources;
+	mxs_dma->dma_device.device_free_chan_resources = mxs_dma_free_chan_resources;
+	mxs_dma->dma_device.device_tx_status = mxs_dma_tx_status;
+	mxs_dma->dma_device.device_prep_slave_sg = mxs_dma_prep_slave_sg;
+	mxs_dma->dma_device.device_prep_dma_cyclic = mxs_dma_prep_dma_cyclic;
+	mxs_dma->dma_device.device_pause = mxs_dma_pause_chan;
+	mxs_dma->dma_device.device_resume = mxs_dma_resume_chan;
+	mxs_dma->dma_device.device_terminate_all = mxs_dma_terminate_all;
+	mxs_dma->dma_device.src_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_4_BYTES);
+	mxs_dma->dma_device.dst_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_4_BYTES);
+	mxs_dma->dma_device.directions = BIT(DMA_DEV_TO_MEM) | BIT(DMA_MEM_TO_DEV);
+	mxs_dma->dma_device.residue_granularity = DMA_RESIDUE_GRANULARITY_BURST;
+	mxs_dma->dma_device.device_issue_pending = mxs_dma_enable_chan;
+
+	ret = dmaenginem_async_device_register(&mxs_dma->dma_device);
+	if (ret) {
+		dev_err(mxs_dma->dma_device.dev, "unable to register\n");
+		return ret;
+	}
+
+	ret = of_dma_controller_register(np, mxs_dma_xlate, mxs_dma);
+	if (ret) {
+		dev_err(mxs_dma->dma_device.dev,
+			"failed to register controller\n");
+	}
+
+	dev_info(mxs_dma->dma_device.dev, "initialized\n");
+
+	return 0;
+}
+
+static struct platform_driver mxs_dma_driver = {
+	.driver		= {
+		.name	= "mxs-dma",
+		.of_match_table = mxs_dma_dt_ids,
+	},
+	.probe = mxs_dma_probe,
+};
+
+builtin_platform_driver(mxs_dma_driver);