dmaengine: zxdma: Support ZTE ZX296702 dma

Add ZTE ZX296702 dma controller support. Only
device tree probe is support currently.
Signed-off-by: Jun Nie <jun.nie@linaro.org>
Reviewed-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

drivers/dma/Kconfig

@@ -458,6 +458,13 @@ config XGENE_DMA
 	select ASYNC_TX_ENABLE_CHANNEL_SWITCH
 	help
 	  Enable support for the APM X-Gene SoC DMA engine.
+config ZX_DMA
+	tristate "ZTE ZX296702 DMA support"
+	depends on ARCH_ZX
+	select DMA_ENGINE
+	select DMA_VIRTUAL_CHANNELS
+	help
+	  Support the DMA engine for ZTE ZX296702 platform devices.
 
 config DMA_ENGINE
 	bool

drivers/dma/Makefile

@@ -56,3 +56,4 @@ obj-$(CONFIG_NBPFAXI_DMA) += nbpfaxi.o
 obj-$(CONFIG_DMA_SUN6I) += sun6i-dma.o
 obj-$(CONFIG_IMG_MDC_DMA) += img-mdc-dma.o
 obj-$(CONFIG_XGENE_DMA) += xgene-dma.o
+obj-$(CONFIG_ZX_DMA) += zx296702_dma.o

drivers/dma/zx296702_dma.c

+/*
+ * Copyright 2015 Linaro.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#include <linux/sched.h>
+#include <linux/device.h>
+#include <linux/dmaengine.h>
+#include <linux/dma-mapping.h>
+#include <linux/dmapool.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/of_device.h>
+#include <linux/of.h>
+#include <linux/clk.h>
+#include <linux/of_dma.h>
+
+#include "virt-dma.h"
+
+#define DRIVER_NAME		"zx-dma"
+#define DMA_ALIGN		4
+#define DMA_MAX_SIZE		(0x10000 - PAGE_SIZE)
+#define LLI_BLOCK_SIZE		(4 * PAGE_SIZE)
+
+#define REG_ZX_SRC_ADDR			0x00
+#define REG_ZX_DST_ADDR			0x04
+#define REG_ZX_TX_X_COUNT		0x08
+#define REG_ZX_TX_ZY_COUNT		0x0c
+#define REG_ZX_SRC_ZY_STEP		0x10
+#define REG_ZX_DST_ZY_STEP		0x14
+#define REG_ZX_LLI_ADDR			0x1c
+#define REG_ZX_CTRL			0x20
+#define REG_ZX_TC_IRQ			0x800
+#define REG_ZX_SRC_ERR_IRQ		0x804
+#define REG_ZX_DST_ERR_IRQ		0x808
+#define REG_ZX_CFG_ERR_IRQ		0x80c
+#define REG_ZX_TC_IRQ_RAW		0x810
+#define REG_ZX_SRC_ERR_IRQ_RAW		0x814
+#define REG_ZX_DST_ERR_IRQ_RAW		0x818
+#define REG_ZX_CFG_ERR_IRQ_RAW		0x81c
+#define REG_ZX_STATUS			0x820
+#define REG_ZX_DMA_GRP_PRIO		0x824
+#define REG_ZX_DMA_ARB			0x828
+
+#define ZX_FORCE_CLOSE			BIT(31)
+#define ZX_DST_BURST_WIDTH(x)		(((x) & 0x7) << 13)
+#define ZX_MAX_BURST_LEN		16
+#define ZX_SRC_BURST_LEN(x)		(((x) & 0xf) << 9)
+#define ZX_SRC_BURST_WIDTH(x)		(((x) & 0x7) << 6)
+#define ZX_IRQ_ENABLE_ALL		(3 << 4)
+#define ZX_DST_FIFO_MODE		BIT(3)
+#define ZX_SRC_FIFO_MODE		BIT(2)
+#define ZX_SOFT_REQ			BIT(1)
+#define ZX_CH_ENABLE			BIT(0)
+
+#define ZX_DMA_BUSWIDTHS \
+	(BIT(DMA_SLAVE_BUSWIDTH_UNDEFINED) | \
+	BIT(DMA_SLAVE_BUSWIDTH_1_BYTE) | \
+	BIT(DMA_SLAVE_BUSWIDTH_2_BYTES) | \
+	BIT(DMA_SLAVE_BUSWIDTH_4_BYTES) | \
+	BIT(DMA_SLAVE_BUSWIDTH_8_BYTES))
+
+enum zx_dma_burst_width {
+	ZX_DMA_WIDTH_8BIT	= 0,
+	ZX_DMA_WIDTH_16BIT	= 1,
+	ZX_DMA_WIDTH_32BIT	= 2,
+	ZX_DMA_WIDTH_64BIT	= 3,
+};
+
+struct zx_desc_hw {
+	u32 saddr;
+	u32 daddr;
+	u32 src_x;
+	u32 src_zy;
+	u32 src_zy_step;
+	u32 dst_zy_step;
+	u32 reserved1;
+	u32 lli;
+	u32 ctr;
+	u32 reserved[7]; /* pack as hardware registers region size */
+} __aligned(32);
+
+struct zx_dma_desc_sw {
+	struct virt_dma_desc	vd;
+	dma_addr_t		desc_hw_lli;
+	size_t			desc_num;
+	size_t			size;
+	struct zx_desc_hw	*desc_hw;
+};
+
+struct zx_dma_phy;
+
+struct zx_dma_chan {
+	struct dma_slave_config slave_cfg;
+	int			id; /* Request phy chan id */
+	u32			ccfg;
+	struct virt_dma_chan	vc;
+	struct zx_dma_phy	*phy;
+	struct list_head	node;
+	dma_addr_t		dev_addr;
+	enum dma_status		status;
+};
+
+struct zx_dma_phy {
+	u32			idx;
+	void __iomem		*base;
+	struct zx_dma_chan	*vchan;
+	struct zx_dma_desc_sw	*ds_run;
+	struct zx_dma_desc_sw	*ds_done;
+};
+
+struct zx_dma_dev {
+	struct dma_device	slave;
+	void __iomem		*base;
+	spinlock_t		lock; /* lock for ch and phy */
+	struct list_head	chan_pending;
+	struct zx_dma_phy	*phy;
+	struct zx_dma_chan	*chans;
+	struct clk		*clk;
+	struct dma_pool		*pool;
+	u32			dma_channels;
+	u32			dma_requests;
+};
+
+#define to_zx_dma(dmadev) container_of(dmadev, struct zx_dma_dev, slave)
+
+static struct zx_dma_chan *to_zx_chan(struct dma_chan *chan)
+{
+	return container_of(chan, struct zx_dma_chan, vc.chan);
+}
+
+static void zx_dma_terminate_chan(struct zx_dma_phy *phy, struct zx_dma_dev *d)
+{
+	u32 val = 0;
+
+	val = readl_relaxed(phy->base + REG_ZX_CTRL);
+	val &= ~ZX_CH_ENABLE;
+	writel_relaxed(val, phy->base + REG_ZX_CTRL);
+
+	val = 0x1 << phy->idx;
+	writel_relaxed(val, d->base + REG_ZX_TC_IRQ_RAW);
+	writel_relaxed(val, d->base + REG_ZX_SRC_ERR_IRQ_RAW);
+	writel_relaxed(val, d->base + REG_ZX_DST_ERR_IRQ_RAW);
+	writel_relaxed(val, d->base + REG_ZX_CFG_ERR_IRQ_RAW);
+}
+
+static void zx_dma_set_desc(struct zx_dma_phy *phy, struct zx_desc_hw *hw)
+{
+	writel_relaxed(hw->saddr, phy->base + REG_ZX_SRC_ADDR);
+	writel_relaxed(hw->daddr, phy->base + REG_ZX_DST_ADDR);
+	writel_relaxed(hw->src_x, phy->base + REG_ZX_TX_X_COUNT);
+	writel_relaxed(0, phy->base + REG_ZX_TX_ZY_COUNT);
+	writel_relaxed(0, phy->base + REG_ZX_SRC_ZY_STEP);
+	writel_relaxed(0, phy->base + REG_ZX_DST_ZY_STEP);
+	writel_relaxed(hw->lli, phy->base + REG_ZX_LLI_ADDR);
+	writel_relaxed(hw->ctr, phy->base + REG_ZX_CTRL);
+}
+
+static u32 zx_dma_get_curr_lli(struct zx_dma_phy *phy)
+{
+	return readl_relaxed(phy->base + REG_ZX_LLI_ADDR);
+}
+
+static u32 zx_dma_get_chan_stat(struct zx_dma_dev *d)
+{
+	return readl_relaxed(d->base + REG_ZX_STATUS);
+}
+
+static void zx_dma_init_state(struct zx_dma_dev *d)
+{
+	/* set same priority */
+	writel_relaxed(0x0, d->base + REG_ZX_DMA_ARB);
+	/* clear all irq */
+	writel_relaxed(0xffffffff, d->base + REG_ZX_TC_IRQ_RAW);
+	writel_relaxed(0xffffffff, d->base + REG_ZX_SRC_ERR_IRQ_RAW);
+	writel_relaxed(0xffffffff, d->base + REG_ZX_DST_ERR_IRQ_RAW);
+	writel_relaxed(0xffffffff, d->base + REG_ZX_CFG_ERR_IRQ_RAW);
+}
+
+static int zx_dma_start_txd(struct zx_dma_chan *c)
+{
+	struct zx_dma_dev *d = to_zx_dma(c->vc.chan.device);
+	struct virt_dma_desc *vd = vchan_next_desc(&c->vc);
+
+	if (!c->phy)
+		return -EAGAIN;
+
+	if (BIT(c->phy->idx) & zx_dma_get_chan_stat(d))
+		return -EAGAIN;
+
+	if (vd) {
+		struct zx_dma_desc_sw *ds =
+			container_of(vd, struct zx_dma_desc_sw, vd);
+		/*
+		 * fetch and remove request from vc->desc_issued
+		 * so vc->desc_issued only contains desc pending
+		 */
+		list_del(&ds->vd.node);
+		c->phy->ds_run = ds;
+		c->phy->ds_done = NULL;
+		/* start dma */
+		zx_dma_set_desc(c->phy, ds->desc_hw);
+		return 0;
+	}
+	c->phy->ds_done = NULL;
+	c->phy->ds_run = NULL;
+	return -EAGAIN;
+}
+
+static void zx_dma_task(struct zx_dma_dev *d)
+{
+	struct zx_dma_phy *p;
+	struct zx_dma_chan *c, *cn;
+	unsigned pch, pch_alloc = 0;
+	unsigned long flags;
+
+	/* check new dma request of running channel in vc->desc_issued */
+	list_for_each_entry_safe(c, cn, &d->slave.channels,
+				 vc.chan.device_node) {
+		spin_lock_irqsave(&c->vc.lock, flags);
+		p = c->phy;
+		if (p && p->ds_done && zx_dma_start_txd(c)) {
+			/* No current txd associated with this channel */
+			dev_dbg(d->slave.dev, "pchan %u: free\n", p->idx);
+			/* Mark this channel free */
+			c->phy = NULL;
+			p->vchan = NULL;
+		}
+		spin_unlock_irqrestore(&c->vc.lock, flags);
+	}
+
+	/* check new channel request in d->chan_pending */
+	spin_lock_irqsave(&d->lock, flags);
+	while (!list_empty(&d->chan_pending)) {
+		c = list_first_entry(&d->chan_pending,
+				     struct zx_dma_chan, node);
+		p = &d->phy[c->id];
+		if (!p->vchan) {
+			/* remove from d->chan_pending */
+			list_del_init(&c->node);
+			pch_alloc |= 1 << c->id;
+			/* Mark this channel allocated */
+			p->vchan = c;
+			c->phy = p;
+		} else {
+			dev_dbg(d->slave.dev, "pchan %u: busy!\n", c->id);
+		}
+	}
+	spin_unlock_irqrestore(&d->lock, flags);
+
+	for (pch = 0; pch < d->dma_channels; pch++) {
+		if (pch_alloc & (1 << pch)) {
+			p = &d->phy[pch];
+			c = p->vchan;
+			if (c) {
+				spin_lock_irqsave(&c->vc.lock, flags);
+				zx_dma_start_txd(c);
+				spin_unlock_irqrestore(&c->vc.lock, flags);
+			}
+		}
+	}
+}
+
+static irqreturn_t zx_dma_int_handler(int irq, void *dev_id)
+{
+	struct zx_dma_dev *d = (struct zx_dma_dev *)dev_id;
+	struct zx_dma_phy *p;
+	struct zx_dma_chan *c;
+	u32 tc = readl_relaxed(d->base + REG_ZX_TC_IRQ);
+	u32 serr = readl_relaxed(d->base + REG_ZX_SRC_ERR_IRQ);
+	u32 derr = readl_relaxed(d->base + REG_ZX_DST_ERR_IRQ);
+	u32 cfg = readl_relaxed(d->base + REG_ZX_CFG_ERR_IRQ);
+	u32 i, irq_chan = 0;
+
+	while (tc) {
+		i = __ffs(tc);
+		tc &= ~BIT(i);
+		p = &d->phy[i];
+		c = p->vchan;
+		if (c) {
+			unsigned long flags;
+
+			spin_lock_irqsave(&c->vc.lock, flags);
+			vchan_cookie_complete(&p->ds_run->vd);
+			p->ds_done = p->ds_run;
+			spin_unlock_irqrestore(&c->vc.lock, flags);
+		}
+		irq_chan |= BIT(i);
+	}
+
+	if (serr || derr || cfg)
+		dev_warn(d->slave.dev, "DMA ERR src 0x%x, dst 0x%x, cfg 0x%x\n",
+			 serr, derr, cfg);
+
+	writel_relaxed(irq_chan, d->base + REG_ZX_TC_IRQ_RAW);
+	writel_relaxed(serr, d->base + REG_ZX_SRC_ERR_IRQ_RAW);
+	writel_relaxed(derr, d->base + REG_ZX_DST_ERR_IRQ_RAW);
+	writel_relaxed(cfg, d->base + REG_ZX_CFG_ERR_IRQ_RAW);
+
+	if (irq_chan) {
+		zx_dma_task(d);
+		return IRQ_HANDLED;
+	} else {
+		return IRQ_NONE;
+	}
+}
+
+static void zx_dma_free_chan_resources(struct dma_chan *chan)
+{
+	struct zx_dma_chan *c = to_zx_chan(chan);
+	struct zx_dma_dev *d = to_zx_dma(chan->device);
+	unsigned long flags;
+
+	spin_lock_irqsave(&d->lock, flags);
+	list_del_init(&c->node);
+	spin_unlock_irqrestore(&d->lock, flags);
+
+	vchan_free_chan_resources(&c->vc);
+	c->ccfg = 0;
+}
+
+static enum dma_status zx_dma_tx_status(struct dma_chan *chan,
+					dma_cookie_t cookie,
+					struct dma_tx_state *state)
+{
+	struct zx_dma_chan *c = to_zx_chan(chan);
+	struct zx_dma_phy *p;
+	struct virt_dma_desc *vd;
+	unsigned long flags;
+	enum dma_status ret;
+	size_t bytes = 0;
+
+	ret = dma_cookie_status(&c->vc.chan, cookie, state);
+	if (ret == DMA_COMPLETE || !state)
+		return ret;
+
+	spin_lock_irqsave(&c->vc.lock, flags);
+	p = c->phy;
+	ret = c->status;
+
+	/*
+	 * If the cookie is on our issue queue, then the residue is
+	 * its total size.
+	 */
+	vd = vchan_find_desc(&c->vc, cookie);
+	if (vd) {
+		bytes = container_of(vd, struct zx_dma_desc_sw, vd)->size;
+	} else if ((!p) || (!p->ds_run)) {
+		bytes = 0;
+	} else {
+		struct zx_dma_desc_sw *ds = p->ds_run;
+		u32 clli = 0, index = 0;
+
+		bytes = 0;
+		clli = zx_dma_get_curr_lli(p);
+		index = (clli - ds->desc_hw_lli) / sizeof(struct zx_desc_hw);
+		for (; index < ds->desc_num; index++) {
+			bytes += ds->desc_hw[index].src_x;
+			/* end of lli */
+			if (!ds->desc_hw[index].lli)
+				break;
+		}
+	}
+	spin_unlock_irqrestore(&c->vc.lock, flags);
+	dma_set_residue(state, bytes);
+	return ret;
+}
+
+static void zx_dma_issue_pending(struct dma_chan *chan)
+{
+	struct zx_dma_chan *c = to_zx_chan(chan);
+	struct zx_dma_dev *d = to_zx_dma(chan->device);
+	unsigned long flags;
+	int issue = 0;
+
+	spin_lock_irqsave(&c->vc.lock, flags);
+	/* add request to vc->desc_issued */
+	if (vchan_issue_pending(&c->vc)) {
+		spin_lock(&d->lock);
+		if (!c->phy && list_empty(&c->node)) {
+			/* if new channel, add chan_pending */
+			list_add_tail(&c->node, &d->chan_pending);
+			issue = 1;
+			dev_dbg(d->slave.dev, "vchan %p: issued\n", &c->vc);
+		}
+		spin_unlock(&d->lock);
+	} else {
+		dev_dbg(d->slave.dev, "vchan %p: nothing to issue\n", &c->vc);
+	}
+	spin_unlock_irqrestore(&c->vc.lock, flags);
+
+	if (issue)
+		zx_dma_task(d);
+}
+
+static void zx_dma_fill_desc(struct zx_dma_desc_sw *ds, dma_addr_t dst,
+			     dma_addr_t src, size_t len, u32 num, u32 ccfg)
+{
+	if ((num + 1) < ds->desc_num)
+		ds->desc_hw[num].lli = ds->desc_hw_lli + (num + 1) *
+			sizeof(struct zx_desc_hw);
+	ds->desc_hw[num].saddr = src;
+	ds->desc_hw[num].daddr = dst;
+	ds->desc_hw[num].src_x = len;
+	ds->desc_hw[num].ctr = ccfg;
+}
+
+static struct zx_dma_desc_sw *zx_alloc_desc_resource(int num,
+						     struct dma_chan *chan)
+{
+	struct zx_dma_chan *c = to_zx_chan(chan);
+	struct zx_dma_desc_sw *ds;
+	struct zx_dma_dev *d = to_zx_dma(chan->device);
+	int lli_limit = LLI_BLOCK_SIZE / sizeof(struct zx_desc_hw);
+
+	if (num > lli_limit) {
+		dev_dbg(chan->device->dev, "vch %p: sg num %d exceed max %d\n",
+			&c->vc, num, lli_limit);
+		return NULL;
+	}
+
+	ds = kzalloc(sizeof(*ds), GFP_ATOMIC);
+	if (!ds)
+		return NULL;
+
+	ds->desc_hw = dma_pool_alloc(d->pool, GFP_NOWAIT, &ds->desc_hw_lli);
+	if (!ds->desc_hw) {
+		dev_dbg(chan->device->dev, "vch %p: dma alloc fail\n", &c->vc);
+		kfree(ds);
+		return NULL;
+	}
+	memset(ds->desc_hw, sizeof(struct zx_desc_hw) * num, 0);
+	ds->desc_num = num;
+	return ds;
+}
+
+static enum zx_dma_burst_width zx_dma_burst_width(enum dma_slave_buswidth width)
+{
+	switch (width) {
+	case DMA_SLAVE_BUSWIDTH_1_BYTE:
+	case DMA_SLAVE_BUSWIDTH_2_BYTES:
+	case DMA_SLAVE_BUSWIDTH_4_BYTES:
+	case DMA_SLAVE_BUSWIDTH_8_BYTES:
+		return ffs(width) - 1;
+	default:
+		return ZX_DMA_WIDTH_32BIT;
+	}
+}
+
+static int zx_pre_config(struct zx_dma_chan *c, enum dma_transfer_direction dir)
+{
+	struct dma_slave_config *cfg = &c->slave_cfg;
+	enum zx_dma_burst_width src_width;
+	enum zx_dma_burst_width dst_width;
+	u32 maxburst = 0;
+
+	switch (dir) {
+	case DMA_MEM_TO_MEM:
+		c->ccfg = ZX_CH_ENABLE | ZX_SOFT_REQ
+			| ZX_SRC_BURST_LEN(ZX_MAX_BURST_LEN - 1)
+			| ZX_SRC_BURST_WIDTH(ZX_DMA_WIDTH_32BIT)
+			| ZX_DST_BURST_WIDTH(ZX_DMA_WIDTH_32BIT);
+		break;
+	case DMA_MEM_TO_DEV:
+		c->dev_addr = cfg->dst_addr;
+		/* dst len is calculated from src width, len and dst width.
+		 * We need make sure dst len not exceed MAX LEN.
+		 */
+		dst_width = zx_dma_burst_width(cfg->dst_addr_width);
+		maxburst = cfg->dst_maxburst * cfg->dst_addr_width
+				/ DMA_SLAVE_BUSWIDTH_8_BYTES;
+		maxburst = maxburst < ZX_MAX_BURST_LEN ?
+				maxburst : ZX_MAX_BURST_LEN;
+		c->ccfg = ZX_DST_FIFO_MODE | ZX_CH_ENABLE
+			| ZX_SRC_BURST_LEN(maxburst - 1)
+			| ZX_SRC_BURST_WIDTH(ZX_DMA_WIDTH_64BIT)
+			| ZX_DST_BURST_WIDTH(dst_width);
+		break;
+	case DMA_DEV_TO_MEM:
+		c->dev_addr = cfg->src_addr;
+		src_width = zx_dma_burst_width(cfg->src_addr_width);
+		maxburst = cfg->src_maxburst;
+		maxburst = maxburst < ZX_MAX_BURST_LEN ?
+				maxburst : ZX_MAX_BURST_LEN;
+		c->ccfg = ZX_SRC_FIFO_MODE | ZX_CH_ENABLE
+			| ZX_SRC_BURST_LEN(maxburst - 1)
+			| ZX_SRC_BURST_WIDTH(src_width)
+			| ZX_DST_BURST_WIDTH(ZX_DMA_WIDTH_64BIT);
+		break;
+	default:
+		return -EINVAL;
+	}
+	return 0;
+}
+
+static struct dma_async_tx_descriptor *zx_dma_prep_memcpy(
+	struct dma_chan *chan,	dma_addr_t dst, dma_addr_t src,
+	size_t len, unsigned long flags)
+{
+	struct zx_dma_chan *c = to_zx_chan(chan);
+	struct zx_dma_desc_sw *ds;
+	size_t copy = 0;
+	int num = 0;
+
+	if (!len)
+		return NULL;
+
+	if (zx_pre_config(c, DMA_MEM_TO_MEM))
+		return NULL;
+
+	num = DIV_ROUND_UP(len, DMA_MAX_SIZE);
+
+	ds = zx_alloc_desc_resource(num, chan);
+	if (!ds)
+		return NULL;
+
+	ds->size = len;
+	num = 0;
+
+	do {
+		copy = min_t(size_t, len, DMA_MAX_SIZE);
+		zx_dma_fill_desc(ds, dst, src, copy, num++, c->ccfg);
+
+		src += copy;
+		dst += copy;
+		len -= copy;
+	} while (len);
+
+	ds->desc_hw[num - 1].lli = 0;	/* end of link */
+	ds->desc_hw[num - 1].ctr |= ZX_IRQ_ENABLE_ALL;
+	return vchan_tx_prep(&c->vc, &ds->vd, flags);
+}
+
+static struct dma_async_tx_descriptor *zx_dma_prep_slave_sg(
+	struct dma_chan *chan, struct scatterlist *sgl, unsigned int sglen,
+	enum dma_transfer_direction dir, unsigned long flags, void *context)
+{
+	struct zx_dma_chan *c = to_zx_chan(chan);
+	struct zx_dma_desc_sw *ds;
+	size_t len, avail, total = 0;
+	struct scatterlist *sg;
+	dma_addr_t addr, src = 0, dst = 0;
+	int num = sglen, i;
+
+	if (!sgl)
+		return NULL;
+
+	if (zx_pre_config(c, dir))
+		return NULL;
+
+	for_each_sg(sgl, sg, sglen, i) {
+		avail = sg_dma_len(sg);
+		if (avail > DMA_MAX_SIZE)
+			num += DIV_ROUND_UP(avail, DMA_MAX_SIZE) - 1;
+	}
+
+	ds = zx_alloc_desc_resource(num, chan);
+	if (!ds)
+		return NULL;
+
+	num = 0;
+	for_each_sg(sgl, sg, sglen, i) {
+		addr = sg_dma_address(sg);
+		avail = sg_dma_len(sg);
+		total += avail;
+
+		do {
+			len = min_t(size_t, avail, DMA_MAX_SIZE);
+
+			if (dir == DMA_MEM_TO_DEV) {
+				src = addr;
+				dst = c->dev_addr;
+			} else if (dir == DMA_DEV_TO_MEM) {
+				src = c->dev_addr;
+				dst = addr;
+			}
+
+			zx_dma_fill_desc(ds, dst, src, len, num++, c->ccfg);
+
+			addr += len;
+			avail -= len;
+		} while (avail);
+	}
+
+	ds->desc_hw[num - 1].lli = 0;	/* end of link */
+	ds->desc_hw[num - 1].ctr |= ZX_IRQ_ENABLE_ALL;
+	ds->size = total;
+	return vchan_tx_prep(&c->vc, &ds->vd, flags);
+}
+
+static int zx_dma_config(struct dma_chan *chan,
+			 struct dma_slave_config *cfg)
+{
+	struct zx_dma_chan *c = to_zx_chan(chan);
+
+	if (!cfg)
+		return -EINVAL;
+
+	memcpy(&c->slave_cfg, cfg, sizeof(*cfg));
+
+	return 0;
+}
+
+static int zx_dma_terminate_all(struct dma_chan *chan)
+{
+	struct zx_dma_chan *c = to_zx_chan(chan);
+	struct zx_dma_dev *d = to_zx_dma(chan->device);
+	struct zx_dma_phy *p = c->phy;
+	unsigned long flags;
+	LIST_HEAD(head);
+
+	dev_dbg(d->slave.dev, "vchan %p: terminate all\n", &c->vc);
+
+	/* Prevent this channel being scheduled */
+	spin_lock(&d->lock);
+	list_del_init(&c->node);
+	spin_unlock(&d->lock);
+
+	/* Clear the tx descriptor lists */
+	spin_lock_irqsave(&c->vc.lock, flags);
+	vchan_get_all_descriptors(&c->vc, &head);
+	if (p) {
+		/* vchan is assigned to a pchan - stop the channel */
+		zx_dma_terminate_chan(p, d);
+		c->phy = NULL;
+		p->vchan = NULL;
+		p->ds_run = NULL;
+		p->ds_done = NULL;
+	}
+	spin_unlock_irqrestore(&c->vc.lock, flags);
+	vchan_dma_desc_free_list(&c->vc, &head);
+
+	return 0;
+}
+
+static void zx_dma_free_desc(struct virt_dma_desc *vd)
+{
+	struct zx_dma_desc_sw *ds =
+		container_of(vd, struct zx_dma_desc_sw, vd);
+	struct zx_dma_dev *d = to_zx_dma(vd->tx.chan->device);
+
+	dma_pool_free(d->pool, ds->desc_hw, ds->desc_hw_lli);
+	kfree(ds);
+}
+
+static const struct of_device_id zx6702_dma_dt_ids[] = {
+	{ .compatible = "zte,zx296702-dma", },
+	{}
+};
+MODULE_DEVICE_TABLE(of, zx6702_dma_dt_ids);
+
+static struct dma_chan *zx_of_dma_simple_xlate(struct of_phandle_args *dma_spec,
+					       struct of_dma *ofdma)
+{
+	struct zx_dma_dev *d = ofdma->of_dma_data;
+	unsigned int request = dma_spec->args[0];
+	struct dma_chan *chan;
+	struct zx_dma_chan *c;
+
+	if (request > d->dma_requests)
+		return NULL;
+
+	chan = dma_get_any_slave_channel(&d->slave);
+	if (!chan) {
+		dev_err(d->slave.dev, "get channel fail in %s.\n", __func__);
+		return NULL;
+	}
+	c = to_zx_chan(chan);
+	c->id = request;
+	dev_info(d->slave.dev, "zx_dma: pchan %u: alloc vchan %p\n",
+		 c->id, &c->vc);
+	return chan;
+}
+
+static int zx_dma_probe(struct platform_device *op)
+{
+	struct zx_dma_dev *d;
+	struct resource *iores;
+	int i, ret = 0, irq = 0;
+
+	iores = platform_get_resource(op, IORESOURCE_MEM, 0);
+	if (!iores)
+		return -EINVAL;
+
+	d = devm_kzalloc(&op->dev, sizeof(*d), GFP_KERNEL);
+	if (!d)
+		return -ENOMEM;
+
+	d->base = devm_ioremap_resource(&op->dev, iores);
+	if (IS_ERR(d->base))
+		return PTR_ERR(d->base);
+
+	of_property_read_u32((&op->dev)->of_node,
+			     "dma-channels", &d->dma_channels);
+	of_property_read_u32((&op->dev)->of_node,
+			     "dma-requests", &d->dma_requests);
+	if (!d->dma_requests || !d->dma_channels)
+		return -EINVAL;
+
+	d->clk = devm_clk_get(&op->dev, NULL);
+	if (IS_ERR(d->clk)) {
+		dev_err(&op->dev, "no dma clk\n");
+		return PTR_ERR(d->clk);
+	}
+
+	irq = platform_get_irq(op, 0);
+	ret = devm_request_irq(&op->dev, irq, zx_dma_int_handler,
+			       0, DRIVER_NAME, d);
+	if (ret)
+		return ret;
+
+	/* A DMA memory pool for LLIs, align on 32-byte boundary */
+	d->pool = dmam_pool_create(DRIVER_NAME, &op->dev,
+			LLI_BLOCK_SIZE, 32, 0);
+	if (!d->pool)
+		return -ENOMEM;
+
+	/* init phy channel */
+	d->phy = devm_kzalloc(&op->dev,
+		d->dma_channels * sizeof(struct zx_dma_phy), GFP_KERNEL);
+	if (!d->phy)
+		return -ENOMEM;
+
+	for (i = 0; i < d->dma_channels; i++) {
+		struct zx_dma_phy *p = &d->phy[i];
+
+		p->idx = i;
+		p->base = d->base + i * 0x40;
+	}
+
+	INIT_LIST_HEAD(&d->slave.channels);
+	dma_cap_set(DMA_SLAVE, d->slave.cap_mask);
+	dma_cap_set(DMA_MEMCPY, d->slave.cap_mask);
+	dma_cap_set(DMA_PRIVATE, d->slave.cap_mask);
+	d->slave.dev = &op->dev;
+	d->slave.device_free_chan_resources = zx_dma_free_chan_resources;
+	d->slave.device_tx_status = zx_dma_tx_status;
+	d->slave.device_prep_dma_memcpy = zx_dma_prep_memcpy;
+	d->slave.device_prep_slave_sg = zx_dma_prep_slave_sg;
+	d->slave.device_issue_pending = zx_dma_issue_pending;
+	d->slave.device_config = zx_dma_config;
+	d->slave.device_terminate_all = zx_dma_terminate_all;
+	d->slave.copy_align = DMA_ALIGN;
+	d->slave.src_addr_widths = ZX_DMA_BUSWIDTHS;
+	d->slave.dst_addr_widths = ZX_DMA_BUSWIDTHS;
+	d->slave.directions = BIT(DMA_MEM_TO_MEM) | BIT(DMA_MEM_TO_DEV)
+			| BIT(DMA_DEV_TO_MEM);
+	d->slave.residue_granularity = DMA_RESIDUE_GRANULARITY_SEGMENT;
+
+	/* init virtual channel */
+	d->chans = devm_kzalloc(&op->dev,
+		d->dma_requests * sizeof(struct zx_dma_chan), GFP_KERNEL);
+	if (!d->chans)
+		return -ENOMEM;
+
+	for (i = 0; i < d->dma_requests; i++) {
+		struct zx_dma_chan *c = &d->chans[i];
+
+		c->status = DMA_IN_PROGRESS;
+		INIT_LIST_HEAD(&c->node);
+		c->vc.desc_free = zx_dma_free_desc;
+		vchan_init(&c->vc, &d->slave);
+	}
+
+	/* Enable clock before accessing registers */
+	ret = clk_prepare_enable(d->clk);
+	if (ret < 0) {
+		dev_err(&op->dev, "clk_prepare_enable failed: %d\n", ret);
+		goto zx_dma_out;
+	}
+
+	zx_dma_init_state(d);
+
+	spin_lock_init(&d->lock);
+	INIT_LIST_HEAD(&d->chan_pending);
+	platform_set_drvdata(op, d);
+
+	ret = dma_async_device_register(&d->slave);
+	if (ret)
+		goto clk_dis;
+
+	ret = of_dma_controller_register((&op->dev)->of_node,
+					 zx_of_dma_simple_xlate, d);
+	if (ret)
+		goto of_dma_register_fail;
+
+	dev_info(&op->dev, "initialized\n");
+	return 0;
+
+of_dma_register_fail:
+	dma_async_device_unregister(&d->slave);
+clk_dis:
+	clk_disable_unprepare(d->clk);
+zx_dma_out:
+	return ret;
+}
+
+static int zx_dma_remove(struct platform_device *op)
+{
+	struct zx_dma_chan *c, *cn;
+	struct zx_dma_dev *d = platform_get_drvdata(op);
+
+	dma_async_device_unregister(&d->slave);
+	of_dma_controller_free((&op->dev)->of_node);
+
+	list_for_each_entry_safe(c, cn, &d->slave.channels,
+				 vc.chan.device_node) {
+		list_del(&c->vc.chan.device_node);
+	}
+	clk_disable_unprepare(d->clk);
+	dmam_pool_destroy(d->pool);
+
+	return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int zx_dma_suspend_dev(struct device *dev)
+{
+	struct zx_dma_dev *d = dev_get_drvdata(dev);
+	u32 stat = 0;
+
+	stat = zx_dma_get_chan_stat(d);
+	if (stat) {
+		dev_warn(d->slave.dev,
+			 "chan %d is running fail to suspend\n", stat);
+		return -1;
+	}
+	clk_disable_unprepare(d->clk);
+	return 0;
+}
+
+static int zx_dma_resume_dev(struct device *dev)
+{
+	struct zx_dma_dev *d = dev_get_drvdata(dev);
+	int ret = 0;
+
+	ret = clk_prepare_enable(d->clk);
+	if (ret < 0) {
+		dev_err(d->slave.dev, "clk_prepare_enable failed: %d\n", ret);
+		return ret;
+	}
+	zx_dma_init_state(d);
+	return 0;
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(zx_dma_pmops, zx_dma_suspend_dev, zx_dma_resume_dev);
+
+static struct platform_driver zx_pdma_driver = {
+	.driver		= {
+		.name	= DRIVER_NAME,
+		.pm	= &zx_dma_pmops,
+		.of_match_table = zx6702_dma_dt_ids,
+	},
+	.probe		= zx_dma_probe,
+	.remove		= zx_dma_remove,
+};
+
+module_platform_driver(zx_pdma_driver);
+
+MODULE_DESCRIPTION("ZTE ZX296702 DMA Driver");
+MODULE_AUTHOR("Jun Nie jun.nie@linaro.org");
+MODULE_LICENSE("GPL v2");