Adding upstream version 5.10.209.upstream/5.10.209

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

5 files changed, 2699 insertions, 0 deletions

diff --git a/drivers/dma/mediatek/Kconfig b/drivers/dma/mediatek/Kconfig
new file mode 100644
index 000000000..7a46a5455
--- /dev/null
+++ b/drivers/dma/mediatek/Kconfig
@@ -0,0 +1,38 @@
+# SPDX-License-Identifier: GPL-2.0-only
+
+config MTK_HSDMA
+	tristate "MediaTek High-Speed DMA controller support"
+	depends on ARCH_MEDIATEK || COMPILE_TEST
+	select DMA_ENGINE
+	select DMA_VIRTUAL_CHANNELS
+	help
+	  Enable support for High-Speed DMA controller on MediaTek
+	  SoCs.
+
+	  This controller provides the channels which is dedicated to
+	  memory-to-memory transfer to offload from CPU through ring-
+	  based descriptor management.
+
+config MTK_CQDMA
+	tristate "MediaTek Command-Queue DMA controller support"
+	depends on ARCH_MEDIATEK || COMPILE_TEST
+	select DMA_ENGINE
+	select DMA_VIRTUAL_CHANNELS
+	select ASYNC_TX_ENABLE_CHANNEL_SWITCH
+	help
+	  Enable support for Command-Queue DMA controller on MediaTek
+	  SoCs.
+
+	  This controller provides the channels which is dedicated to
+	  memory-to-memory transfer to offload from CPU.
+
+config MTK_UART_APDMA
+	tristate "MediaTek SoCs APDMA support for UART"
+	depends on OF && SERIAL_8250_MT6577
+	select DMA_ENGINE
+	select DMA_VIRTUAL_CHANNELS
+	help
+	  Support for the UART DMA engine found on MediaTek MTK SoCs.
+	  When SERIAL_8250_MT6577 is enabled, and if you want to use DMA,
+	  you can enable the config. The DMA engine can only be used
+	  with MediaTek SoCs.
diff --git a/drivers/dma/mediatek/Makefile b/drivers/dma/mediatek/Makefile
new file mode 100644
index 000000000..5ba39a5ed
--- /dev/null
+++ b/drivers/dma/mediatek/Makefile
@@ -0,0 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0-only
+obj-$(CONFIG_MTK_UART_APDMA) += mtk-uart-apdma.o
+obj-$(CONFIG_MTK_HSDMA) += mtk-hsdma.o
+obj-$(CONFIG_MTK_CQDMA) += mtk-cqdma.o
diff --git a/drivers/dma/mediatek/mtk-cqdma.c b/drivers/dma/mediatek/mtk-cqdma.c
new file mode 100644
index 000000000..41ef9f15d
--- /dev/null
+++ b/drivers/dma/mediatek/mtk-cqdma.c
@@ -0,0 +1,942 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2018-2019 MediaTek Inc.
+
+/*
+ * Driver for MediaTek Command-Queue DMA Controller
+ *
+ * Author: Shun-Chih Yu <shun-chih.yu@mediatek.com>
+ *
+ */
+
+#include <linux/bitops.h>
+#include <linux/clk.h>
+#include <linux/dmaengine.h>
+#include <linux/dma-mapping.h>
+#include <linux/err.h>
+#include <linux/iopoll.h>
+#include <linux/interrupt.h>
+#include <linux/list.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/of_dma.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/refcount.h>
+#include <linux/slab.h>
+
+#include "../virt-dma.h"
+
+#define MTK_CQDMA_USEC_POLL		10
+#define MTK_CQDMA_TIMEOUT_POLL		1000
+#define MTK_CQDMA_DMA_BUSWIDTHS		BIT(DMA_SLAVE_BUSWIDTH_4_BYTES)
+#define MTK_CQDMA_ALIGN_SIZE		1
+
+/* The default number of virtual channel */
+#define MTK_CQDMA_NR_VCHANS		32
+
+/* The default number of physical channel */
+#define MTK_CQDMA_NR_PCHANS		3
+
+/* Registers for underlying dma manipulation */
+#define MTK_CQDMA_INT_FLAG		0x0
+#define MTK_CQDMA_INT_EN		0x4
+#define MTK_CQDMA_EN			0x8
+#define MTK_CQDMA_RESET			0xc
+#define MTK_CQDMA_FLUSH			0x14
+#define MTK_CQDMA_SRC			0x1c
+#define MTK_CQDMA_DST			0x20
+#define MTK_CQDMA_LEN1			0x24
+#define MTK_CQDMA_LEN2			0x28
+#define MTK_CQDMA_SRC2			0x60
+#define MTK_CQDMA_DST2			0x64
+
+/* Registers setting */
+#define MTK_CQDMA_EN_BIT		BIT(0)
+#define MTK_CQDMA_INT_FLAG_BIT		BIT(0)
+#define MTK_CQDMA_INT_EN_BIT		BIT(0)
+#define MTK_CQDMA_FLUSH_BIT		BIT(0)
+
+#define MTK_CQDMA_WARM_RST_BIT		BIT(0)
+#define MTK_CQDMA_HARD_RST_BIT		BIT(1)
+
+#define MTK_CQDMA_MAX_LEN		GENMASK(27, 0)
+#define MTK_CQDMA_ADDR_LIMIT		GENMASK(31, 0)
+#define MTK_CQDMA_ADDR2_SHFIT		(32)
+
+/**
+ * struct mtk_cqdma_vdesc - The struct holding info describing virtual
+ *                         descriptor (CVD)
+ * @vd:                    An instance for struct virt_dma_desc
+ * @len:                   The total data size device wants to move
+ * @residue:               The remaining data size device will move
+ * @dest:                  The destination address device wants to move to
+ * @src:                   The source address device wants to move from
+ * @ch:                    The pointer to the corresponding dma channel
+ * @node:                  The lise_head struct to build link-list for VDs
+ * @parent:                The pointer to the parent CVD
+ */
+struct mtk_cqdma_vdesc {
+	struct virt_dma_desc vd;
+	size_t len;
+	size_t residue;
+	dma_addr_t dest;
+	dma_addr_t src;
+	struct dma_chan *ch;
+
+	struct list_head node;
+	struct mtk_cqdma_vdesc *parent;
+};
+
+/**
+ * struct mtk_cqdma_pchan - The struct holding info describing physical
+ *                         channel (PC)
+ * @queue:                 Queue for the PDs issued to this PC
+ * @base:                  The mapped register I/O base of this PC
+ * @irq:                   The IRQ that this PC are using
+ * @refcnt:                Track how many VCs are using this PC
+ * @tasklet:               Tasklet for this PC
+ * @lock:                  Lock protect agaisting multiple VCs access PC
+ */
+struct mtk_cqdma_pchan {
+	struct list_head queue;
+	void __iomem *base;
+	u32 irq;
+
+	refcount_t refcnt;
+
+	struct tasklet_struct tasklet;
+
+	/* lock to protect PC */
+	spinlock_t lock;
+};
+
+/**
+ * struct mtk_cqdma_vchan - The struct holding info describing virtual
+ *                         channel (VC)
+ * @vc:                    An instance for struct virt_dma_chan
+ * @pc:                    The pointer to the underlying PC
+ * @issue_completion:	   The wait for all issued descriptors completited
+ * @issue_synchronize:	   Bool indicating channel synchronization starts
+ */
+struct mtk_cqdma_vchan {
+	struct virt_dma_chan vc;
+	struct mtk_cqdma_pchan *pc;
+	struct completion issue_completion;
+	bool issue_synchronize;
+};
+
+/**
+ * struct mtk_cqdma_device - The struct holding info describing CQDMA
+ *                          device
+ * @ddev:                   An instance for struct dma_device
+ * @clk:                    The clock that device internal is using
+ * @dma_requests:           The number of VCs the device supports to
+ * @dma_channels:           The number of PCs the device supports to
+ * @vc:                     The pointer to all available VCs
+ * @pc:                     The pointer to all the underlying PCs
+ */
+struct mtk_cqdma_device {
+	struct dma_device ddev;
+	struct clk *clk;
+
+	u32 dma_requests;
+	u32 dma_channels;
+	struct mtk_cqdma_vchan *vc;
+	struct mtk_cqdma_pchan **pc;
+};
+
+static struct mtk_cqdma_device *to_cqdma_dev(struct dma_chan *chan)
+{
+	return container_of(chan->device, struct mtk_cqdma_device, ddev);
+}
+
+static struct mtk_cqdma_vchan *to_cqdma_vchan(struct dma_chan *chan)
+{
+	return container_of(chan, struct mtk_cqdma_vchan, vc.chan);
+}
+
+static struct mtk_cqdma_vdesc *to_cqdma_vdesc(struct virt_dma_desc *vd)
+{
+	return container_of(vd, struct mtk_cqdma_vdesc, vd);
+}
+
+static struct device *cqdma2dev(struct mtk_cqdma_device *cqdma)
+{
+	return cqdma->ddev.dev;
+}
+
+static u32 mtk_dma_read(struct mtk_cqdma_pchan *pc, u32 reg)
+{
+	return readl(pc->base + reg);
+}
+
+static void mtk_dma_write(struct mtk_cqdma_pchan *pc, u32 reg, u32 val)
+{
+	writel_relaxed(val, pc->base + reg);
+}
+
+static void mtk_dma_rmw(struct mtk_cqdma_pchan *pc, u32 reg,
+			u32 mask, u32 set)
+{
+	u32 val;
+
+	val = mtk_dma_read(pc, reg);
+	val &= ~mask;
+	val |= set;
+	mtk_dma_write(pc, reg, val);
+}
+
+static void mtk_dma_set(struct mtk_cqdma_pchan *pc, u32 reg, u32 val)
+{
+	mtk_dma_rmw(pc, reg, 0, val);
+}
+
+static void mtk_dma_clr(struct mtk_cqdma_pchan *pc, u32 reg, u32 val)
+{
+	mtk_dma_rmw(pc, reg, val, 0);
+}
+
+static void mtk_cqdma_vdesc_free(struct virt_dma_desc *vd)
+{
+	kfree(to_cqdma_vdesc(vd));
+}
+
+static int mtk_cqdma_poll_engine_done(struct mtk_cqdma_pchan *pc, bool atomic)
+{
+	u32 status = 0;
+
+	if (!atomic)
+		return readl_poll_timeout(pc->base + MTK_CQDMA_EN,
+					  status,
+					  !(status & MTK_CQDMA_EN_BIT),
+					  MTK_CQDMA_USEC_POLL,
+					  MTK_CQDMA_TIMEOUT_POLL);
+
+	return readl_poll_timeout_atomic(pc->base + MTK_CQDMA_EN,
+					 status,
+					 !(status & MTK_CQDMA_EN_BIT),
+					 MTK_CQDMA_USEC_POLL,
+					 MTK_CQDMA_TIMEOUT_POLL);
+}
+
+static int mtk_cqdma_hard_reset(struct mtk_cqdma_pchan *pc)
+{
+	mtk_dma_set(pc, MTK_CQDMA_RESET, MTK_CQDMA_HARD_RST_BIT);
+	mtk_dma_clr(pc, MTK_CQDMA_RESET, MTK_CQDMA_HARD_RST_BIT);
+
+	return mtk_cqdma_poll_engine_done(pc, true);
+}
+
+static void mtk_cqdma_start(struct mtk_cqdma_pchan *pc,
+			    struct mtk_cqdma_vdesc *cvd)
+{
+	/* wait for the previous transaction done */
+	if (mtk_cqdma_poll_engine_done(pc, true) < 0)
+		dev_err(cqdma2dev(to_cqdma_dev(cvd->ch)), "cqdma wait transaction timeout\n");
+
+	/* warm reset the dma engine for the new transaction */
+	mtk_dma_set(pc, MTK_CQDMA_RESET, MTK_CQDMA_WARM_RST_BIT);
+	if (mtk_cqdma_poll_engine_done(pc, true) < 0)
+		dev_err(cqdma2dev(to_cqdma_dev(cvd->ch)), "cqdma warm reset timeout\n");
+
+	/* setup the source */
+	mtk_dma_set(pc, MTK_CQDMA_SRC, cvd->src & MTK_CQDMA_ADDR_LIMIT);
+#ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT
+	mtk_dma_set(pc, MTK_CQDMA_SRC2, cvd->src >> MTK_CQDMA_ADDR2_SHFIT);
+#else
+	mtk_dma_set(pc, MTK_CQDMA_SRC2, 0);
+#endif
+
+	/* setup the destination */
+	mtk_dma_set(pc, MTK_CQDMA_DST, cvd->dest & MTK_CQDMA_ADDR_LIMIT);
+#ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT
+	mtk_dma_set(pc, MTK_CQDMA_DST2, cvd->dest >> MTK_CQDMA_ADDR2_SHFIT);
+#else
+	mtk_dma_set(pc, MTK_CQDMA_DST2, 0);
+#endif
+
+	/* setup the length */
+	mtk_dma_set(pc, MTK_CQDMA_LEN1, cvd->len);
+
+	/* start dma engine */
+	mtk_dma_set(pc, MTK_CQDMA_EN, MTK_CQDMA_EN_BIT);
+}
+
+static void mtk_cqdma_issue_vchan_pending(struct mtk_cqdma_vchan *cvc)
+{
+	struct virt_dma_desc *vd, *vd2;
+	struct mtk_cqdma_pchan *pc = cvc->pc;
+	struct mtk_cqdma_vdesc *cvd;
+	bool trigger_engine = false;
+
+	lockdep_assert_held(&cvc->vc.lock);
+	lockdep_assert_held(&pc->lock);
+
+	list_for_each_entry_safe(vd, vd2, &cvc->vc.desc_issued, node) {
+		/* need to trigger dma engine if PC's queue is empty */
+		if (list_empty(&pc->queue))
+			trigger_engine = true;
+
+		cvd = to_cqdma_vdesc(vd);
+
+		/* add VD into PC's queue */
+		list_add_tail(&cvd->node, &pc->queue);
+
+		/* start the dma engine */
+		if (trigger_engine)
+			mtk_cqdma_start(pc, cvd);
+
+		/* remove VD from list desc_issued */
+		list_del(&vd->node);
+	}
+}
+
+/*
+ * return true if this VC is active,
+ * meaning that there are VDs under processing by the PC
+ */
+static bool mtk_cqdma_is_vchan_active(struct mtk_cqdma_vchan *cvc)
+{
+	struct mtk_cqdma_vdesc *cvd;
+
+	list_for_each_entry(cvd, &cvc->pc->queue, node)
+		if (cvc == to_cqdma_vchan(cvd->ch))
+			return true;
+
+	return false;
+}
+
+/*
+ * return the pointer of the CVD that is just consumed by the PC
+ */
+static struct mtk_cqdma_vdesc
+*mtk_cqdma_consume_work_queue(struct mtk_cqdma_pchan *pc)
+{
+	struct mtk_cqdma_vchan *cvc;
+	struct mtk_cqdma_vdesc *cvd, *ret = NULL;
+
+	/* consume a CVD from PC's queue */
+	cvd = list_first_entry_or_null(&pc->queue,
+				       struct mtk_cqdma_vdesc, node);
+	if (unlikely(!cvd || !cvd->parent))
+		return NULL;
+
+	cvc = to_cqdma_vchan(cvd->ch);
+	ret = cvd;
+
+	/* update residue of the parent CVD */
+	cvd->parent->residue -= cvd->len;
+
+	/* delete CVD from PC's queue */
+	list_del(&cvd->node);
+
+	spin_lock(&cvc->vc.lock);
+
+	/* check whether all the child CVDs completed */
+	if (!cvd->parent->residue) {
+		/* add the parent VD into list desc_completed */
+		vchan_cookie_complete(&cvd->parent->vd);
+
+		/* setup completion if this VC is under synchronization */
+		if (cvc->issue_synchronize && !mtk_cqdma_is_vchan_active(cvc)) {
+			complete(&cvc->issue_completion);
+			cvc->issue_synchronize = false;
+		}
+	}
+
+	spin_unlock(&cvc->vc.lock);
+
+	/* start transaction for next CVD in the queue */
+	cvd = list_first_entry_or_null(&pc->queue,
+				       struct mtk_cqdma_vdesc, node);
+	if (cvd)
+		mtk_cqdma_start(pc, cvd);
+
+	return ret;
+}
+
+static void mtk_cqdma_tasklet_cb(struct tasklet_struct *t)
+{
+	struct mtk_cqdma_pchan *pc = from_tasklet(pc, t, tasklet);
+	struct mtk_cqdma_vdesc *cvd = NULL;
+	unsigned long flags;
+
+	spin_lock_irqsave(&pc->lock, flags);
+	/* consume the queue */
+	cvd = mtk_cqdma_consume_work_queue(pc);
+	spin_unlock_irqrestore(&pc->lock, flags);
+
+	/* submit the next CVD */
+	if (cvd) {
+		dma_run_dependencies(&cvd->vd.tx);
+
+		/*
+		 * free child CVD after completion.
+		 * the parent CVD would be freeed with desc_free by user.
+		 */
+		if (cvd->parent != cvd)
+			kfree(cvd);
+	}
+
+	/* re-enable interrupt before leaving tasklet */
+	enable_irq(pc->irq);
+}
+
+static irqreturn_t mtk_cqdma_irq(int irq, void *devid)
+{
+	struct mtk_cqdma_device *cqdma = devid;
+	irqreturn_t ret = IRQ_NONE;
+	bool schedule_tasklet = false;
+	u32 i;
+
+	/* clear interrupt flags for each PC */
+	for (i = 0; i < cqdma->dma_channels; ++i, schedule_tasklet = false) {
+		spin_lock(&cqdma->pc[i]->lock);
+		if (mtk_dma_read(cqdma->pc[i],
+				 MTK_CQDMA_INT_FLAG) & MTK_CQDMA_INT_FLAG_BIT) {
+			/* clear interrupt */
+			mtk_dma_clr(cqdma->pc[i], MTK_CQDMA_INT_FLAG,
+				    MTK_CQDMA_INT_FLAG_BIT);
+
+			schedule_tasklet = true;
+			ret = IRQ_HANDLED;
+		}
+		spin_unlock(&cqdma->pc[i]->lock);
+
+		if (schedule_tasklet) {
+			/* disable interrupt */
+			disable_irq_nosync(cqdma->pc[i]->irq);
+
+			/* schedule the tasklet to handle the transactions */
+			tasklet_schedule(&cqdma->pc[i]->tasklet);
+		}
+	}
+
+	return ret;
+}
+
+static struct virt_dma_desc *mtk_cqdma_find_active_desc(struct dma_chan *c,
+							dma_cookie_t cookie)
+{
+	struct mtk_cqdma_vchan *cvc = to_cqdma_vchan(c);
+	struct virt_dma_desc *vd;
+	unsigned long flags;
+
+	spin_lock_irqsave(&cvc->pc->lock, flags);
+	list_for_each_entry(vd, &cvc->pc->queue, node)
+		if (vd->tx.cookie == cookie) {
+			spin_unlock_irqrestore(&cvc->pc->lock, flags);
+			return vd;
+		}
+	spin_unlock_irqrestore(&cvc->pc->lock, flags);
+
+	list_for_each_entry(vd, &cvc->vc.desc_issued, node)
+		if (vd->tx.cookie == cookie)
+			return vd;
+
+	return NULL;
+}
+
+static enum dma_status mtk_cqdma_tx_status(struct dma_chan *c,
+					   dma_cookie_t cookie,
+					   struct dma_tx_state *txstate)
+{
+	struct mtk_cqdma_vchan *cvc = to_cqdma_vchan(c);
+	struct mtk_cqdma_vdesc *cvd;
+	struct virt_dma_desc *vd;
+	enum dma_status ret;
+	unsigned long flags;
+	size_t bytes = 0;
+
+	ret = dma_cookie_status(c, cookie, txstate);
+	if (ret == DMA_COMPLETE || !txstate)
+		return ret;
+
+	spin_lock_irqsave(&cvc->vc.lock, flags);
+	vd = mtk_cqdma_find_active_desc(c, cookie);
+	spin_unlock_irqrestore(&cvc->vc.lock, flags);
+
+	if (vd) {
+		cvd = to_cqdma_vdesc(vd);
+		bytes = cvd->residue;
+	}
+
+	dma_set_residue(txstate, bytes);
+
+	return ret;
+}
+
+static void mtk_cqdma_issue_pending(struct dma_chan *c)
+{
+	struct mtk_cqdma_vchan *cvc = to_cqdma_vchan(c);
+	unsigned long pc_flags;
+	unsigned long vc_flags;
+
+	/* acquire PC's lock before VS's lock for lock dependency in tasklet */
+	spin_lock_irqsave(&cvc->pc->lock, pc_flags);
+	spin_lock_irqsave(&cvc->vc.lock, vc_flags);
+
+	if (vchan_issue_pending(&cvc->vc))
+		mtk_cqdma_issue_vchan_pending(cvc);
+
+	spin_unlock_irqrestore(&cvc->vc.lock, vc_flags);
+	spin_unlock_irqrestore(&cvc->pc->lock, pc_flags);
+}
+
+static struct dma_async_tx_descriptor *
+mtk_cqdma_prep_dma_memcpy(struct dma_chan *c, dma_addr_t dest,
+			  dma_addr_t src, size_t len, unsigned long flags)
+{
+	struct mtk_cqdma_vdesc **cvd;
+	struct dma_async_tx_descriptor *tx = NULL, *prev_tx = NULL;
+	size_t i, tlen, nr_vd;
+
+	/*
+	 * In the case that trsanction length is larger than the
+	 * DMA engine supports, a single memcpy transaction needs
+	 * to be separated into several DMA transactions.
+	 * Each DMA transaction would be described by a CVD,
+	 * and the first one is referred as the parent CVD,
+	 * while the others are child CVDs.
+	 * The parent CVD's tx descriptor is the only tx descriptor
+	 * returned to the DMA user, and it should not be completed
+	 * until all the child CVDs completed.
+	 */
+	nr_vd = DIV_ROUND_UP(len, MTK_CQDMA_MAX_LEN);
+	cvd = kcalloc(nr_vd, sizeof(*cvd), GFP_NOWAIT);
+	if (!cvd)
+		return NULL;
+
+	for (i = 0; i < nr_vd; ++i) {
+		cvd[i] = kzalloc(sizeof(*cvd[i]), GFP_NOWAIT);
+		if (!cvd[i]) {
+			for (; i > 0; --i)
+				kfree(cvd[i - 1]);
+			return NULL;
+		}
+
+		/* setup dma channel */
+		cvd[i]->ch = c;
+
+		/* setup sourece, destination, and length */
+		tlen = (len > MTK_CQDMA_MAX_LEN) ? MTK_CQDMA_MAX_LEN : len;
+		cvd[i]->len = tlen;
+		cvd[i]->src = src;
+		cvd[i]->dest = dest;
+
+		/* setup tx descriptor */
+		tx = vchan_tx_prep(to_virt_chan(c), &cvd[i]->vd, flags);
+		tx->next = NULL;
+
+		if (!i) {
+			cvd[0]->residue = len;
+		} else {
+			prev_tx->next = tx;
+			cvd[i]->residue = tlen;
+		}
+
+		cvd[i]->parent = cvd[0];
+
+		/* update the src, dest, len, prev_tx for the next CVD */
+		src += tlen;
+		dest += tlen;
+		len -= tlen;
+		prev_tx = tx;
+	}
+
+	return &cvd[0]->vd.tx;
+}
+
+static void mtk_cqdma_free_inactive_desc(struct dma_chan *c)
+{
+	struct virt_dma_chan *vc = to_virt_chan(c);
+	unsigned long flags;
+	LIST_HEAD(head);
+
+	/*
+	 * set desc_allocated, desc_submitted,
+	 * and desc_issued as the candicates to be freed
+	 */
+	spin_lock_irqsave(&vc->lock, flags);
+	list_splice_tail_init(&vc->desc_allocated, &head);
+	list_splice_tail_init(&vc->desc_submitted, &head);
+	list_splice_tail_init(&vc->desc_issued, &head);
+	spin_unlock_irqrestore(&vc->lock, flags);
+
+	/* free descriptor lists */
+	vchan_dma_desc_free_list(vc, &head);
+}
+
+static void mtk_cqdma_free_active_desc(struct dma_chan *c)
+{
+	struct mtk_cqdma_vchan *cvc = to_cqdma_vchan(c);
+	bool sync_needed = false;
+	unsigned long pc_flags;
+	unsigned long vc_flags;
+
+	/* acquire PC's lock first due to lock dependency in dma ISR */
+	spin_lock_irqsave(&cvc->pc->lock, pc_flags);
+	spin_lock_irqsave(&cvc->vc.lock, vc_flags);
+
+	/* synchronization is required if this VC is active */
+	if (mtk_cqdma_is_vchan_active(cvc)) {
+		cvc->issue_synchronize = true;
+		sync_needed = true;
+	}
+
+	spin_unlock_irqrestore(&cvc->vc.lock, vc_flags);
+	spin_unlock_irqrestore(&cvc->pc->lock, pc_flags);
+
+	/* waiting for the completion of this VC */
+	if (sync_needed)
+		wait_for_completion(&cvc->issue_completion);
+
+	/* free all descriptors in list desc_completed */
+	vchan_synchronize(&cvc->vc);
+
+	WARN_ONCE(!list_empty(&cvc->vc.desc_completed),
+		  "Desc pending still in list desc_completed\n");
+}
+
+static int mtk_cqdma_terminate_all(struct dma_chan *c)
+{
+	/* free descriptors not processed yet by hardware */
+	mtk_cqdma_free_inactive_desc(c);
+
+	/* free descriptors being processed by hardware */
+	mtk_cqdma_free_active_desc(c);
+
+	return 0;
+}
+
+static int mtk_cqdma_alloc_chan_resources(struct dma_chan *c)
+{
+	struct mtk_cqdma_device *cqdma = to_cqdma_dev(c);
+	struct mtk_cqdma_vchan *vc = to_cqdma_vchan(c);
+	struct mtk_cqdma_pchan *pc = NULL;
+	u32 i, min_refcnt = U32_MAX, refcnt;
+	unsigned long flags;
+
+	/* allocate PC with the minimun refcount */
+	for (i = 0; i < cqdma->dma_channels; ++i) {
+		refcnt = refcount_read(&cqdma->pc[i]->refcnt);
+		if (refcnt < min_refcnt) {
+			pc = cqdma->pc[i];
+			min_refcnt = refcnt;
+		}
+	}
+
+	if (!pc)
+		return -ENOSPC;
+
+	spin_lock_irqsave(&pc->lock, flags);
+
+	if (!refcount_read(&pc->refcnt)) {
+		/* allocate PC when the refcount is zero */
+		mtk_cqdma_hard_reset(pc);
+
+		/* enable interrupt for this PC */
+		mtk_dma_set(pc, MTK_CQDMA_INT_EN, MTK_CQDMA_INT_EN_BIT);
+
+		/*
+		 * refcount_inc would complain increment on 0; use-after-free.
+		 * Thus, we need to explicitly set it as 1 initially.
+		 */
+		refcount_set(&pc->refcnt, 1);
+	} else {
+		refcount_inc(&pc->refcnt);
+	}
+
+	spin_unlock_irqrestore(&pc->lock, flags);
+
+	vc->pc = pc;
+
+	return 0;
+}
+
+static void mtk_cqdma_free_chan_resources(struct dma_chan *c)
+{
+	struct mtk_cqdma_vchan *cvc = to_cqdma_vchan(c);
+	unsigned long flags;
+
+	/* free all descriptors in all lists on the VC */
+	mtk_cqdma_terminate_all(c);
+
+	spin_lock_irqsave(&cvc->pc->lock, flags);
+
+	/* PC is not freed until there is no VC mapped to it */
+	if (refcount_dec_and_test(&cvc->pc->refcnt)) {
+		/* start the flush operation and stop the engine */
+		mtk_dma_set(cvc->pc, MTK_CQDMA_FLUSH, MTK_CQDMA_FLUSH_BIT);
+
+		/* wait for the completion of flush operation */
+		if (mtk_cqdma_poll_engine_done(cvc->pc, true) < 0)
+			dev_err(cqdma2dev(to_cqdma_dev(c)), "cqdma flush timeout\n");
+
+		/* clear the flush bit and interrupt flag */
+		mtk_dma_clr(cvc->pc, MTK_CQDMA_FLUSH, MTK_CQDMA_FLUSH_BIT);
+		mtk_dma_clr(cvc->pc, MTK_CQDMA_INT_FLAG,
+			    MTK_CQDMA_INT_FLAG_BIT);
+
+		/* disable interrupt for this PC */
+		mtk_dma_clr(cvc->pc, MTK_CQDMA_INT_EN, MTK_CQDMA_INT_EN_BIT);
+	}
+
+	spin_unlock_irqrestore(&cvc->pc->lock, flags);
+}
+
+static int mtk_cqdma_hw_init(struct mtk_cqdma_device *cqdma)
+{
+	unsigned long flags;
+	int err;
+	u32 i;
+
+	pm_runtime_enable(cqdma2dev(cqdma));
+	pm_runtime_get_sync(cqdma2dev(cqdma));
+
+	err = clk_prepare_enable(cqdma->clk);
+
+	if (err) {
+		pm_runtime_put_sync(cqdma2dev(cqdma));
+		pm_runtime_disable(cqdma2dev(cqdma));
+		return err;
+	}
+
+	/* reset all PCs */
+	for (i = 0; i < cqdma->dma_channels; ++i) {
+		spin_lock_irqsave(&cqdma->pc[i]->lock, flags);
+		if (mtk_cqdma_hard_reset(cqdma->pc[i]) < 0) {
+			dev_err(cqdma2dev(cqdma), "cqdma hard reset timeout\n");
+			spin_unlock_irqrestore(&cqdma->pc[i]->lock, flags);
+
+			clk_disable_unprepare(cqdma->clk);
+			pm_runtime_put_sync(cqdma2dev(cqdma));
+			pm_runtime_disable(cqdma2dev(cqdma));
+			return -EINVAL;
+		}
+		spin_unlock_irqrestore(&cqdma->pc[i]->lock, flags);
+	}
+
+	return 0;
+}
+
+static void mtk_cqdma_hw_deinit(struct mtk_cqdma_device *cqdma)
+{
+	unsigned long flags;
+	u32 i;
+
+	/* reset all PCs */
+	for (i = 0; i < cqdma->dma_channels; ++i) {
+		spin_lock_irqsave(&cqdma->pc[i]->lock, flags);
+		if (mtk_cqdma_hard_reset(cqdma->pc[i]) < 0)
+			dev_err(cqdma2dev(cqdma), "cqdma hard reset timeout\n");
+		spin_unlock_irqrestore(&cqdma->pc[i]->lock, flags);
+	}
+
+	clk_disable_unprepare(cqdma->clk);
+
+	pm_runtime_put_sync(cqdma2dev(cqdma));
+	pm_runtime_disable(cqdma2dev(cqdma));
+}
+
+static const struct of_device_id mtk_cqdma_match[] = {
+	{ .compatible = "mediatek,mt6765-cqdma" },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, mtk_cqdma_match);
+
+static int mtk_cqdma_probe(struct platform_device *pdev)
+{
+	struct mtk_cqdma_device *cqdma;
+	struct mtk_cqdma_vchan *vc;
+	struct dma_device *dd;
+	struct resource *res;
+	int err;
+	u32 i;
+
+	cqdma = devm_kzalloc(&pdev->dev, sizeof(*cqdma), GFP_KERNEL);
+	if (!cqdma)
+		return -ENOMEM;
+
+	dd = &cqdma->ddev;
+
+	cqdma->clk = devm_clk_get(&pdev->dev, "cqdma");
+	if (IS_ERR(cqdma->clk)) {
+		dev_err(&pdev->dev, "No clock for %s\n",
+			dev_name(&pdev->dev));
+		return PTR_ERR(cqdma->clk);
+	}
+
+	dma_cap_set(DMA_MEMCPY, dd->cap_mask);
+
+	dd->copy_align = MTK_CQDMA_ALIGN_SIZE;
+	dd->device_alloc_chan_resources = mtk_cqdma_alloc_chan_resources;
+	dd->device_free_chan_resources = mtk_cqdma_free_chan_resources;
+	dd->device_tx_status = mtk_cqdma_tx_status;
+	dd->device_issue_pending = mtk_cqdma_issue_pending;
+	dd->device_prep_dma_memcpy = mtk_cqdma_prep_dma_memcpy;
+	dd->device_terminate_all = mtk_cqdma_terminate_all;
+	dd->src_addr_widths = MTK_CQDMA_DMA_BUSWIDTHS;
+	dd->dst_addr_widths = MTK_CQDMA_DMA_BUSWIDTHS;
+	dd->directions = BIT(DMA_MEM_TO_MEM);
+	dd->residue_granularity = DMA_RESIDUE_GRANULARITY_SEGMENT;
+	dd->dev = &pdev->dev;
+	INIT_LIST_HEAD(&dd->channels);
+
+	if (pdev->dev.of_node && of_property_read_u32(pdev->dev.of_node,
+						      "dma-requests",
+						      &cqdma->dma_requests)) {
+		dev_info(&pdev->dev,
+			 "Using %u as missing dma-requests property\n",
+			 MTK_CQDMA_NR_VCHANS);
+
+		cqdma->dma_requests = MTK_CQDMA_NR_VCHANS;
+	}
+
+	if (pdev->dev.of_node && of_property_read_u32(pdev->dev.of_node,
+						      "dma-channels",
+						      &cqdma->dma_channels)) {
+		dev_info(&pdev->dev,
+			 "Using %u as missing dma-channels property\n",
+			 MTK_CQDMA_NR_PCHANS);
+
+		cqdma->dma_channels = MTK_CQDMA_NR_PCHANS;
+	}
+
+	cqdma->pc = devm_kcalloc(&pdev->dev, cqdma->dma_channels,
+				 sizeof(*cqdma->pc), GFP_KERNEL);
+	if (!cqdma->pc)
+		return -ENOMEM;
+
+	/* initialization for PCs */
+	for (i = 0; i < cqdma->dma_channels; ++i) {
+		cqdma->pc[i] = devm_kcalloc(&pdev->dev, 1,
+					    sizeof(**cqdma->pc), GFP_KERNEL);
+		if (!cqdma->pc[i])
+			return -ENOMEM;
+
+		INIT_LIST_HEAD(&cqdma->pc[i]->queue);
+		spin_lock_init(&cqdma->pc[i]->lock);
+		refcount_set(&cqdma->pc[i]->refcnt, 0);
+		cqdma->pc[i]->base = devm_platform_ioremap_resource(pdev, i);
+		if (IS_ERR(cqdma->pc[i]->base))
+			return PTR_ERR(cqdma->pc[i]->base);
+
+		/* allocate IRQ resource */
+		res = platform_get_resource(pdev, IORESOURCE_IRQ, i);
+		if (!res) {
+			dev_err(&pdev->dev, "No irq resource for %s\n",
+				dev_name(&pdev->dev));
+			return -EINVAL;
+		}
+		cqdma->pc[i]->irq = res->start;
+
+		err = devm_request_irq(&pdev->dev, cqdma->pc[i]->irq,
+				       mtk_cqdma_irq, 0, dev_name(&pdev->dev),
+				       cqdma);
+		if (err) {
+			dev_err(&pdev->dev,
+				"request_irq failed with err %d\n", err);
+			return -EINVAL;
+		}
+	}
+
+	/* allocate resource for VCs */
+	cqdma->vc = devm_kcalloc(&pdev->dev, cqdma->dma_requests,
+				 sizeof(*cqdma->vc), GFP_KERNEL);
+	if (!cqdma->vc)
+		return -ENOMEM;
+
+	for (i = 0; i < cqdma->dma_requests; i++) {
+		vc = &cqdma->vc[i];
+		vc->vc.desc_free = mtk_cqdma_vdesc_free;
+		vchan_init(&vc->vc, dd);
+		init_completion(&vc->issue_completion);
+	}
+
+	err = dma_async_device_register(dd);
+	if (err)
+		return err;
+
+	err = of_dma_controller_register(pdev->dev.of_node,
+					 of_dma_xlate_by_chan_id, cqdma);
+	if (err) {
+		dev_err(&pdev->dev,
+			"MediaTek CQDMA OF registration failed %d\n", err);
+		goto err_unregister;
+	}
+
+	err = mtk_cqdma_hw_init(cqdma);
+	if (err) {
+		dev_err(&pdev->dev,
+			"MediaTek CQDMA HW initialization failed %d\n", err);
+		goto err_unregister;
+	}
+
+	platform_set_drvdata(pdev, cqdma);
+
+	/* initialize tasklet for each PC */
+	for (i = 0; i < cqdma->dma_channels; ++i)
+		tasklet_setup(&cqdma->pc[i]->tasklet, mtk_cqdma_tasklet_cb);
+
+	dev_info(&pdev->dev, "MediaTek CQDMA driver registered\n");
+
+	return 0;
+
+err_unregister:
+	dma_async_device_unregister(dd);
+
+	return err;
+}
+
+static int mtk_cqdma_remove(struct platform_device *pdev)
+{
+	struct mtk_cqdma_device *cqdma = platform_get_drvdata(pdev);
+	struct mtk_cqdma_vchan *vc;
+	unsigned long flags;
+	int i;
+
+	/* kill VC task */
+	for (i = 0; i < cqdma->dma_requests; i++) {
+		vc = &cqdma->vc[i];
+
+		list_del(&vc->vc.chan.device_node);
+		tasklet_kill(&vc->vc.task);
+	}
+
+	/* disable interrupt */
+	for (i = 0; i < cqdma->dma_channels; i++) {
+		spin_lock_irqsave(&cqdma->pc[i]->lock, flags);
+		mtk_dma_clr(cqdma->pc[i], MTK_CQDMA_INT_EN,
+			    MTK_CQDMA_INT_EN_BIT);
+		spin_unlock_irqrestore(&cqdma->pc[i]->lock, flags);
+
+		/* Waits for any pending IRQ handlers to complete */
+		synchronize_irq(cqdma->pc[i]->irq);
+
+		tasklet_kill(&cqdma->pc[i]->tasklet);
+	}
+
+	/* disable hardware */
+	mtk_cqdma_hw_deinit(cqdma);
+
+	dma_async_device_unregister(&cqdma->ddev);
+	of_dma_controller_free(pdev->dev.of_node);
+
+	return 0;
+}
+
+static struct platform_driver mtk_cqdma_driver = {
+	.probe = mtk_cqdma_probe,
+	.remove = mtk_cqdma_remove,
+	.driver = {
+		.name           = KBUILD_MODNAME,
+		.of_match_table = mtk_cqdma_match,
+	},
+};
+module_platform_driver(mtk_cqdma_driver);
+
+MODULE_DESCRIPTION("MediaTek CQDMA Controller Driver");
+MODULE_AUTHOR("Shun-Chih Yu <shun-chih.yu@mediatek.com>");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/dma/mediatek/mtk-hsdma.c b/drivers/dma/mediatek/mtk-hsdma.c
new file mode 100644
index 000000000..6ad8afbb9
--- /dev/null
+++ b/drivers/dma/mediatek/mtk-hsdma.c
@@ -0,0 +1,1059 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2017-2018 MediaTek Inc.
+
+/*
+ * Driver for MediaTek High-Speed DMA Controller
+ *
+ * Author: Sean Wang <sean.wang@mediatek.com>
+ *
+ */
+
+#include <linux/bitops.h>
+#include <linux/clk.h>
+#include <linux/dmaengine.h>
+#include <linux/dma-mapping.h>
+#include <linux/err.h>
+#include <linux/iopoll.h>
+#include <linux/list.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/of_dma.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/refcount.h>
+#include <linux/slab.h>
+
+#include "../virt-dma.h"
+
+#define MTK_HSDMA_USEC_POLL		20
+#define MTK_HSDMA_TIMEOUT_POLL		200000
+#define MTK_HSDMA_DMA_BUSWIDTHS		BIT(DMA_SLAVE_BUSWIDTH_4_BYTES)
+
+/* The default number of virtual channel */
+#define MTK_HSDMA_NR_VCHANS		3
+
+/* Only one physical channel supported */
+#define MTK_HSDMA_NR_MAX_PCHANS		1
+
+/* Macro for physical descriptor (PD) manipulation */
+/* The number of PD which must be 2 of power */
+#define MTK_DMA_SIZE			64
+#define MTK_HSDMA_NEXT_DESP_IDX(x, y)	(((x) + 1) & ((y) - 1))
+#define MTK_HSDMA_LAST_DESP_IDX(x, y)	(((x) - 1) & ((y) - 1))
+#define MTK_HSDMA_MAX_LEN		0x3f80
+#define MTK_HSDMA_ALIGN_SIZE		4
+#define MTK_HSDMA_PLEN_MASK		0x3fff
+#define MTK_HSDMA_DESC_PLEN(x)		(((x) & MTK_HSDMA_PLEN_MASK) << 16)
+#define MTK_HSDMA_DESC_PLEN_GET(x)	(((x) >> 16) & MTK_HSDMA_PLEN_MASK)
+
+/* Registers for underlying ring manipulation */
+#define MTK_HSDMA_TX_BASE		0x0
+#define MTK_HSDMA_TX_CNT		0x4
+#define MTK_HSDMA_TX_CPU		0x8
+#define MTK_HSDMA_TX_DMA		0xc
+#define MTK_HSDMA_RX_BASE		0x100
+#define MTK_HSDMA_RX_CNT		0x104
+#define MTK_HSDMA_RX_CPU		0x108
+#define MTK_HSDMA_RX_DMA		0x10c
+
+/* Registers for global setup */
+#define MTK_HSDMA_GLO			0x204
+#define MTK_HSDMA_GLO_MULTI_DMA		BIT(10)
+#define MTK_HSDMA_TX_WB_DDONE		BIT(6)
+#define MTK_HSDMA_BURST_64BYTES		(0x2 << 4)
+#define MTK_HSDMA_GLO_RX_BUSY		BIT(3)
+#define MTK_HSDMA_GLO_RX_DMA		BIT(2)
+#define MTK_HSDMA_GLO_TX_BUSY		BIT(1)
+#define MTK_HSDMA_GLO_TX_DMA		BIT(0)
+#define MTK_HSDMA_GLO_DMA		(MTK_HSDMA_GLO_TX_DMA |	\
+					 MTK_HSDMA_GLO_RX_DMA)
+#define MTK_HSDMA_GLO_BUSY		(MTK_HSDMA_GLO_RX_BUSY | \
+					 MTK_HSDMA_GLO_TX_BUSY)
+#define MTK_HSDMA_GLO_DEFAULT		(MTK_HSDMA_GLO_TX_DMA | \
+					 MTK_HSDMA_GLO_RX_DMA | \
+					 MTK_HSDMA_TX_WB_DDONE | \
+					 MTK_HSDMA_BURST_64BYTES | \
+					 MTK_HSDMA_GLO_MULTI_DMA)
+
+/* Registers for reset */
+#define MTK_HSDMA_RESET			0x208
+#define MTK_HSDMA_RST_TX		BIT(0)
+#define MTK_HSDMA_RST_RX		BIT(16)
+
+/* Registers for interrupt control */
+#define MTK_HSDMA_DLYINT		0x20c
+#define MTK_HSDMA_RXDLY_INT_EN		BIT(15)
+
+/* Interrupt fires when the pending number's more than the specified */
+#define MTK_HSDMA_RXMAX_PINT(x)		(((x) & 0x7f) << 8)
+
+/* Interrupt fires when the pending time's more than the specified in 20 us */
+#define MTK_HSDMA_RXMAX_PTIME(x)	((x) & 0x7f)
+#define MTK_HSDMA_DLYINT_DEFAULT	(MTK_HSDMA_RXDLY_INT_EN | \
+					 MTK_HSDMA_RXMAX_PINT(20) | \
+					 MTK_HSDMA_RXMAX_PTIME(20))
+#define MTK_HSDMA_INT_STATUS		0x220
+#define MTK_HSDMA_INT_ENABLE		0x228
+#define MTK_HSDMA_INT_RXDONE		BIT(16)
+
+enum mtk_hsdma_vdesc_flag {
+	MTK_HSDMA_VDESC_FINISHED	= 0x01,
+};
+
+#define IS_MTK_HSDMA_VDESC_FINISHED(x) ((x) == MTK_HSDMA_VDESC_FINISHED)
+
+/**
+ * struct mtk_hsdma_pdesc - This is the struct holding info describing physical
+ *			    descriptor (PD) and its placement must be kept at
+ *			    4-bytes alignment in little endian order.
+ * @desc1:		    | The control pad used to indicate hardware how to
+ * @desc2:		    | deal with the descriptor such as source and
+ * @desc3:		    | destination address and data length. The maximum
+ * @desc4:		    | data length each pdesc can handle is 0x3f80 bytes
+ */
+struct mtk_hsdma_pdesc {
+	__le32 desc1;
+	__le32 desc2;
+	__le32 desc3;
+	__le32 desc4;
+} __packed __aligned(4);
+
+/**
+ * struct mtk_hsdma_vdesc - This is the struct holding info describing virtual
+ *			    descriptor (VD)
+ * @vd:			    An instance for struct virt_dma_desc
+ * @len:		    The total data size device wants to move
+ * @residue:		    The remaining data size device will move
+ * @dest:		    The destination address device wants to move to
+ * @src:		    The source address device wants to move from
+ */
+struct mtk_hsdma_vdesc {
+	struct virt_dma_desc vd;
+	size_t len;
+	size_t residue;
+	dma_addr_t dest;
+	dma_addr_t src;
+};
+
+/**
+ * struct mtk_hsdma_cb - This is the struct holding extra info required for RX
+ *			 ring to know what relevant VD the the PD is being
+ *			 mapped to.
+ * @vd:			 Pointer to the relevant VD.
+ * @flag:		 Flag indicating what action should be taken when VD
+ *			 is completed.
+ */
+struct mtk_hsdma_cb {
+	struct virt_dma_desc *vd;
+	enum mtk_hsdma_vdesc_flag flag;
+};
+
+/**
+ * struct mtk_hsdma_ring - This struct holds info describing underlying ring
+ *			   space
+ * @txd:		   The descriptor TX ring which describes DMA source
+ *			   information
+ * @rxd:		   The descriptor RX ring which describes DMA
+ *			   destination information
+ * @cb:			   The extra information pointed at by RX ring
+ * @tphys:		   The physical addr of TX ring
+ * @rphys:		   The physical addr of RX ring
+ * @cur_tptr:		   Pointer to the next free descriptor used by the host
+ * @cur_rptr:		   Pointer to the last done descriptor by the device
+ */
+struct mtk_hsdma_ring {
+	struct mtk_hsdma_pdesc *txd;
+	struct mtk_hsdma_pdesc *rxd;
+	struct mtk_hsdma_cb *cb;
+	dma_addr_t tphys;
+	dma_addr_t rphys;
+	u16 cur_tptr;
+	u16 cur_rptr;
+};
+
+/**
+ * struct mtk_hsdma_pchan - This is the struct holding info describing physical
+ *			   channel (PC)
+ * @ring:		   An instance for the underlying ring
+ * @sz_ring:		   Total size allocated for the ring
+ * @nr_free:		   Total number of free rooms in the ring. It would
+ *			   be accessed and updated frequently between IRQ
+ *			   context and user context to reflect whether ring
+ *			   can accept requests from VD.
+ */
+struct mtk_hsdma_pchan {
+	struct mtk_hsdma_ring ring;
+	size_t sz_ring;
+	atomic_t nr_free;
+};
+
+/**
+ * struct mtk_hsdma_vchan - This is the struct holding info describing virtual
+ *			   channel (VC)
+ * @vc:			   An instance for struct virt_dma_chan
+ * @issue_completion:	   The wait for all issued descriptors completited
+ * @issue_synchronize:	   Bool indicating channel synchronization starts
+ * @desc_hw_processing:	   List those descriptors the hardware is processing,
+ *			   which is protected by vc.lock
+ */
+struct mtk_hsdma_vchan {
+	struct virt_dma_chan vc;
+	struct completion issue_completion;
+	bool issue_synchronize;
+	struct list_head desc_hw_processing;
+};
+
+/**
+ * struct mtk_hsdma_soc - This is the struct holding differences among SoCs
+ * @ddone:		  Bit mask for DDONE
+ * @ls0:		  Bit mask for LS0
+ */
+struct mtk_hsdma_soc {
+	__le32 ddone;
+	__le32 ls0;
+};
+
+/**
+ * struct mtk_hsdma_device - This is the struct holding info describing HSDMA
+ *			     device
+ * @ddev:		     An instance for struct dma_device
+ * @base:		     The mapped register I/O base
+ * @clk:		     The clock that device internal is using
+ * @irq:		     The IRQ that device are using
+ * @dma_requests:	     The number of VCs the device supports to
+ * @vc:			     The pointer to all available VCs
+ * @pc:			     The pointer to the underlying PC
+ * @pc_refcnt:		     Track how many VCs are using the PC
+ * @lock:		     Lock protect agaisting multiple VCs access PC
+ * @soc:		     The pointer to area holding differences among
+ *			     vaious platform
+ */
+struct mtk_hsdma_device {
+	struct dma_device ddev;
+	void __iomem *base;
+	struct clk *clk;
+	u32 irq;
+
+	u32 dma_requests;
+	struct mtk_hsdma_vchan *vc;
+	struct mtk_hsdma_pchan *pc;
+	refcount_t pc_refcnt;
+
+	/* Lock used to protect against multiple VCs access PC */
+	spinlock_t lock;
+
+	const struct mtk_hsdma_soc *soc;
+};
+
+static struct mtk_hsdma_device *to_hsdma_dev(struct dma_chan *chan)
+{
+	return container_of(chan->device, struct mtk_hsdma_device, ddev);
+}
+
+static inline struct mtk_hsdma_vchan *to_hsdma_vchan(struct dma_chan *chan)
+{
+	return container_of(chan, struct mtk_hsdma_vchan, vc.chan);
+}
+
+static struct mtk_hsdma_vdesc *to_hsdma_vdesc(struct virt_dma_desc *vd)
+{
+	return container_of(vd, struct mtk_hsdma_vdesc, vd);
+}
+
+static struct device *hsdma2dev(struct mtk_hsdma_device *hsdma)
+{
+	return hsdma->ddev.dev;
+}
+
+static u32 mtk_dma_read(struct mtk_hsdma_device *hsdma, u32 reg)
+{
+	return readl(hsdma->base + reg);
+}
+
+static void mtk_dma_write(struct mtk_hsdma_device *hsdma, u32 reg, u32 val)
+{
+	writel(val, hsdma->base + reg);
+}
+
+static void mtk_dma_rmw(struct mtk_hsdma_device *hsdma, u32 reg,
+			u32 mask, u32 set)
+{
+	u32 val;
+
+	val = mtk_dma_read(hsdma, reg);
+	val &= ~mask;
+	val |= set;
+	mtk_dma_write(hsdma, reg, val);
+}
+
+static void mtk_dma_set(struct mtk_hsdma_device *hsdma, u32 reg, u32 val)
+{
+	mtk_dma_rmw(hsdma, reg, 0, val);
+}
+
+static void mtk_dma_clr(struct mtk_hsdma_device *hsdma, u32 reg, u32 val)
+{
+	mtk_dma_rmw(hsdma, reg, val, 0);
+}
+
+static void mtk_hsdma_vdesc_free(struct virt_dma_desc *vd)
+{
+	kfree(container_of(vd, struct mtk_hsdma_vdesc, vd));
+}
+
+static int mtk_hsdma_busy_wait(struct mtk_hsdma_device *hsdma)
+{
+	u32 status = 0;
+
+	return readl_poll_timeout(hsdma->base + MTK_HSDMA_GLO, status,
+				  !(status & MTK_HSDMA_GLO_BUSY),
+				  MTK_HSDMA_USEC_POLL,
+				  MTK_HSDMA_TIMEOUT_POLL);
+}
+
+static int mtk_hsdma_alloc_pchan(struct mtk_hsdma_device *hsdma,
+				 struct mtk_hsdma_pchan *pc)
+{
+	struct mtk_hsdma_ring *ring = &pc->ring;
+	int err;
+
+	memset(pc, 0, sizeof(*pc));
+
+	/*
+	 * Allocate ring space where [0 ... MTK_DMA_SIZE - 1] is for TX ring
+	 * and [MTK_DMA_SIZE ... 2 * MTK_DMA_SIZE - 1] is for RX ring.
+	 */
+	pc->sz_ring = 2 * MTK_DMA_SIZE * sizeof(*ring->txd);
+	ring->txd = dma_alloc_coherent(hsdma2dev(hsdma), pc->sz_ring,
+				       &ring->tphys, GFP_NOWAIT);
+	if (!ring->txd)
+		return -ENOMEM;
+
+	ring->rxd = &ring->txd[MTK_DMA_SIZE];
+	ring->rphys = ring->tphys + MTK_DMA_SIZE * sizeof(*ring->txd);
+	ring->cur_tptr = 0;
+	ring->cur_rptr = MTK_DMA_SIZE - 1;
+
+	ring->cb = kcalloc(MTK_DMA_SIZE, sizeof(*ring->cb), GFP_NOWAIT);
+	if (!ring->cb) {
+		err = -ENOMEM;
+		goto err_free_dma;
+	}
+
+	atomic_set(&pc->nr_free, MTK_DMA_SIZE - 1);
+
+	/* Disable HSDMA and wait for the completion */
+	mtk_dma_clr(hsdma, MTK_HSDMA_GLO, MTK_HSDMA_GLO_DMA);
+	err = mtk_hsdma_busy_wait(hsdma);
+	if (err)
+		goto err_free_cb;
+
+	/* Reset */
+	mtk_dma_set(hsdma, MTK_HSDMA_RESET,
+		    MTK_HSDMA_RST_TX | MTK_HSDMA_RST_RX);
+	mtk_dma_clr(hsdma, MTK_HSDMA_RESET,
+		    MTK_HSDMA_RST_TX | MTK_HSDMA_RST_RX);
+
+	/* Setup HSDMA initial pointer in the ring */
+	mtk_dma_write(hsdma, MTK_HSDMA_TX_BASE, ring->tphys);
+	mtk_dma_write(hsdma, MTK_HSDMA_TX_CNT, MTK_DMA_SIZE);
+	mtk_dma_write(hsdma, MTK_HSDMA_TX_CPU, ring->cur_tptr);
+	mtk_dma_write(hsdma, MTK_HSDMA_TX_DMA, 0);
+	mtk_dma_write(hsdma, MTK_HSDMA_RX_BASE, ring->rphys);
+	mtk_dma_write(hsdma, MTK_HSDMA_RX_CNT, MTK_DMA_SIZE);
+	mtk_dma_write(hsdma, MTK_HSDMA_RX_CPU, ring->cur_rptr);
+	mtk_dma_write(hsdma, MTK_HSDMA_RX_DMA, 0);
+
+	/* Enable HSDMA */
+	mtk_dma_set(hsdma, MTK_HSDMA_GLO, MTK_HSDMA_GLO_DMA);
+
+	/* Setup delayed interrupt */
+	mtk_dma_write(hsdma, MTK_HSDMA_DLYINT, MTK_HSDMA_DLYINT_DEFAULT);
+
+	/* Enable interrupt */
+	mtk_dma_set(hsdma, MTK_HSDMA_INT_ENABLE, MTK_HSDMA_INT_RXDONE);
+
+	return 0;
+
+err_free_cb:
+	kfree(ring->cb);
+
+err_free_dma:
+	dma_free_coherent(hsdma2dev(hsdma),
+			  pc->sz_ring, ring->txd, ring->tphys);
+	return err;
+}
+
+static void mtk_hsdma_free_pchan(struct mtk_hsdma_device *hsdma,
+				 struct mtk_hsdma_pchan *pc)
+{
+	struct mtk_hsdma_ring *ring = &pc->ring;
+
+	/* Disable HSDMA and then wait for the completion */
+	mtk_dma_clr(hsdma, MTK_HSDMA_GLO, MTK_HSDMA_GLO_DMA);
+	mtk_hsdma_busy_wait(hsdma);
+
+	/* Reset pointer in the ring */
+	mtk_dma_clr(hsdma, MTK_HSDMA_INT_ENABLE, MTK_HSDMA_INT_RXDONE);
+	mtk_dma_write(hsdma, MTK_HSDMA_TX_BASE, 0);
+	mtk_dma_write(hsdma, MTK_HSDMA_TX_CNT, 0);
+	mtk_dma_write(hsdma, MTK_HSDMA_TX_CPU, 0);
+	mtk_dma_write(hsdma, MTK_HSDMA_RX_BASE, 0);
+	mtk_dma_write(hsdma, MTK_HSDMA_RX_CNT, 0);
+	mtk_dma_write(hsdma, MTK_HSDMA_RX_CPU, MTK_DMA_SIZE - 1);
+
+	kfree(ring->cb);
+
+	dma_free_coherent(hsdma2dev(hsdma),
+			  pc->sz_ring, ring->txd, ring->tphys);
+}
+
+static int mtk_hsdma_issue_pending_vdesc(struct mtk_hsdma_device *hsdma,
+					 struct mtk_hsdma_pchan *pc,
+					 struct mtk_hsdma_vdesc *hvd)
+{
+	struct mtk_hsdma_ring *ring = &pc->ring;
+	struct mtk_hsdma_pdesc *txd, *rxd;
+	u16 reserved, prev, tlen, num_sgs;
+	unsigned long flags;
+
+	/* Protect against PC is accessed by multiple VCs simultaneously */
+	spin_lock_irqsave(&hsdma->lock, flags);
+
+	/*
+	 * Reserve rooms, where pc->nr_free is used to track how many free
+	 * rooms in the ring being updated in user and IRQ context.
+	 */
+	num_sgs = DIV_ROUND_UP(hvd->len, MTK_HSDMA_MAX_LEN);
+	reserved = min_t(u16, num_sgs, atomic_read(&pc->nr_free));
+
+	if (!reserved) {
+		spin_unlock_irqrestore(&hsdma->lock, flags);
+		return -ENOSPC;
+	}
+
+	atomic_sub(reserved, &pc->nr_free);
+
+	while (reserved--) {
+		/* Limit size by PD capability for valid data moving */
+		tlen = (hvd->len > MTK_HSDMA_MAX_LEN) ?
+		       MTK_HSDMA_MAX_LEN : hvd->len;
+
+		/*
+		 * Setup PDs using the remaining VD info mapped on those
+		 * reserved rooms. And since RXD is shared memory between the
+		 * host and the device allocated by dma_alloc_coherent call,
+		 * the helper macro WRITE_ONCE can ensure the data written to
+		 * RAM would really happens.
+		 */
+		txd = &ring->txd[ring->cur_tptr];
+		WRITE_ONCE(txd->desc1, hvd->src);
+		WRITE_ONCE(txd->desc2,
+			   hsdma->soc->ls0 | MTK_HSDMA_DESC_PLEN(tlen));
+
+		rxd = &ring->rxd[ring->cur_tptr];
+		WRITE_ONCE(rxd->desc1, hvd->dest);
+		WRITE_ONCE(rxd->desc2, MTK_HSDMA_DESC_PLEN(tlen));
+
+		/* Associate VD, the PD belonged to */
+		ring->cb[ring->cur_tptr].vd = &hvd->vd;
+
+		/* Move forward the pointer of TX ring */
+		ring->cur_tptr = MTK_HSDMA_NEXT_DESP_IDX(ring->cur_tptr,
+							 MTK_DMA_SIZE);
+
+		/* Update VD with remaining data */
+		hvd->src  += tlen;
+		hvd->dest += tlen;
+		hvd->len  -= tlen;
+	}
+
+	/*
+	 * Tagging flag for the last PD for VD will be responsible for
+	 * completing VD.
+	 */
+	if (!hvd->len) {
+		prev = MTK_HSDMA_LAST_DESP_IDX(ring->cur_tptr, MTK_DMA_SIZE);
+		ring->cb[prev].flag = MTK_HSDMA_VDESC_FINISHED;
+	}
+
+	/* Ensure all changes indeed done before we're going on */
+	wmb();
+
+	/*
+	 * Updating into hardware the pointer of TX ring lets HSDMA to take
+	 * action for those pending PDs.
+	 */
+	mtk_dma_write(hsdma, MTK_HSDMA_TX_CPU, ring->cur_tptr);
+
+	spin_unlock_irqrestore(&hsdma->lock, flags);
+
+	return 0;
+}
+
+static void mtk_hsdma_issue_vchan_pending(struct mtk_hsdma_device *hsdma,
+					  struct mtk_hsdma_vchan *hvc)
+{
+	struct virt_dma_desc *vd, *vd2;
+	int err;
+
+	lockdep_assert_held(&hvc->vc.lock);
+
+	list_for_each_entry_safe(vd, vd2, &hvc->vc.desc_issued, node) {
+		struct mtk_hsdma_vdesc *hvd;
+
+		hvd = to_hsdma_vdesc(vd);
+
+		/* Map VD into PC and all VCs shares a single PC */
+		err = mtk_hsdma_issue_pending_vdesc(hsdma, hsdma->pc, hvd);
+
+		/*
+		 * Move VD from desc_issued to desc_hw_processing when entire
+		 * VD is fit into available PDs. Otherwise, the uncompleted
+		 * VDs would stay in list desc_issued and then restart the
+		 * processing as soon as possible once underlying ring space
+		 * got freed.
+		 */
+		if (err == -ENOSPC || hvd->len > 0)
+			break;
+
+		/*
+		 * The extra list desc_hw_processing is used because
+		 * hardware can't provide sufficient information allowing us
+		 * to know what VDs are still working on the underlying ring.
+		 * Through the additional list, it can help us to implement
+		 * terminate_all, residue calculation and such thing needed
+		 * to know detail descriptor status on the hardware.
+		 */
+		list_move_tail(&vd->node, &hvc->desc_hw_processing);
+	}
+}
+
+static void mtk_hsdma_free_rooms_in_ring(struct mtk_hsdma_device *hsdma)
+{
+	struct mtk_hsdma_vchan *hvc;
+	struct mtk_hsdma_pdesc *rxd;
+	struct mtk_hsdma_vdesc *hvd;
+	struct mtk_hsdma_pchan *pc;
+	struct mtk_hsdma_cb *cb;
+	int i = MTK_DMA_SIZE;
+	__le32 desc2;
+	u32 status;
+	u16 next;
+
+	/* Read IRQ status */
+	status = mtk_dma_read(hsdma, MTK_HSDMA_INT_STATUS);
+	if (unlikely(!(status & MTK_HSDMA_INT_RXDONE)))
+		goto rx_done;
+
+	pc = hsdma->pc;
+
+	/*
+	 * Using a fail-safe loop with iterations of up to MTK_DMA_SIZE to
+	 * reclaim these finished descriptors: The most number of PDs the ISR
+	 * can handle at one time shouldn't be more than MTK_DMA_SIZE so we
+	 * take it as limited count instead of just using a dangerous infinite
+	 * poll.
+	 */
+	while (i--) {
+		next = MTK_HSDMA_NEXT_DESP_IDX(pc->ring.cur_rptr,
+					       MTK_DMA_SIZE);
+		rxd = &pc->ring.rxd[next];
+
+		/*
+		 * If MTK_HSDMA_DESC_DDONE is no specified, that means data
+		 * moving for the PD is still under going.
+		 */
+		desc2 = READ_ONCE(rxd->desc2);
+		if (!(desc2 & hsdma->soc->ddone))
+			break;
+
+		cb = &pc->ring.cb[next];
+		if (unlikely(!cb->vd)) {
+			dev_err(hsdma2dev(hsdma), "cb->vd cannot be null\n");
+			break;
+		}
+
+		/* Update residue of VD the associated PD belonged to */
+		hvd = to_hsdma_vdesc(cb->vd);
+		hvd->residue -= MTK_HSDMA_DESC_PLEN_GET(rxd->desc2);
+
+		/* Complete VD until the relevant last PD is finished */
+		if (IS_MTK_HSDMA_VDESC_FINISHED(cb->flag)) {
+			hvc = to_hsdma_vchan(cb->vd->tx.chan);
+
+			spin_lock(&hvc->vc.lock);
+
+			/* Remove VD from list desc_hw_processing */
+			list_del(&cb->vd->node);
+
+			/* Add VD into list desc_completed */
+			vchan_cookie_complete(cb->vd);
+
+			if (hvc->issue_synchronize &&
+			    list_empty(&hvc->desc_hw_processing)) {
+				complete(&hvc->issue_completion);
+				hvc->issue_synchronize = false;
+			}
+			spin_unlock(&hvc->vc.lock);
+
+			cb->flag = 0;
+		}
+
+		cb->vd = 0;
+
+		/*
+		 * Recycle the RXD with the helper WRITE_ONCE that can ensure
+		 * data written into RAM would really happens.
+		 */
+		WRITE_ONCE(rxd->desc1, 0);
+		WRITE_ONCE(rxd->desc2, 0);
+		pc->ring.cur_rptr = next;
+
+		/* Release rooms */
+		atomic_inc(&pc->nr_free);
+	}
+
+	/* Ensure all changes indeed done before we're going on */
+	wmb();
+
+	/* Update CPU pointer for those completed PDs */
+	mtk_dma_write(hsdma, MTK_HSDMA_RX_CPU, pc->ring.cur_rptr);
+
+	/*
+	 * Acking the pending IRQ allows hardware no longer to keep the used
+	 * IRQ line in certain trigger state when software has completed all
+	 * the finished physical descriptors.
+	 */
+	if (atomic_read(&pc->nr_free) >= MTK_DMA_SIZE - 1)
+		mtk_dma_write(hsdma, MTK_HSDMA_INT_STATUS, status);
+
+	/* ASAP handles pending VDs in all VCs after freeing some rooms */
+	for (i = 0; i < hsdma->dma_requests; i++) {
+		hvc = &hsdma->vc[i];
+		spin_lock(&hvc->vc.lock);
+		mtk_hsdma_issue_vchan_pending(hsdma, hvc);
+		spin_unlock(&hvc->vc.lock);
+	}
+
+rx_done:
+	/* All completed PDs are cleaned up, so enable interrupt again */
+	mtk_dma_set(hsdma, MTK_HSDMA_INT_ENABLE, MTK_HSDMA_INT_RXDONE);
+}
+
+static irqreturn_t mtk_hsdma_irq(int irq, void *devid)
+{
+	struct mtk_hsdma_device *hsdma = devid;
+
+	/*
+	 * Disable interrupt until all completed PDs are cleaned up in
+	 * mtk_hsdma_free_rooms call.
+	 */
+	mtk_dma_clr(hsdma, MTK_HSDMA_INT_ENABLE, MTK_HSDMA_INT_RXDONE);
+
+	mtk_hsdma_free_rooms_in_ring(hsdma);
+
+	return IRQ_HANDLED;
+}
+
+static struct virt_dma_desc *mtk_hsdma_find_active_desc(struct dma_chan *c,
+							dma_cookie_t cookie)
+{
+	struct mtk_hsdma_vchan *hvc = to_hsdma_vchan(c);
+	struct virt_dma_desc *vd;
+
+	list_for_each_entry(vd, &hvc->desc_hw_processing, node)
+		if (vd->tx.cookie == cookie)
+			return vd;
+
+	list_for_each_entry(vd, &hvc->vc.desc_issued, node)
+		if (vd->tx.cookie == cookie)
+			return vd;
+
+	return NULL;
+}
+
+static enum dma_status mtk_hsdma_tx_status(struct dma_chan *c,
+					   dma_cookie_t cookie,
+					   struct dma_tx_state *txstate)
+{
+	struct mtk_hsdma_vchan *hvc = to_hsdma_vchan(c);
+	struct mtk_hsdma_vdesc *hvd;
+	struct virt_dma_desc *vd;
+	enum dma_status ret;
+	unsigned long flags;
+	size_t bytes = 0;
+
+	ret = dma_cookie_status(c, cookie, txstate);
+	if (ret == DMA_COMPLETE || !txstate)
+		return ret;
+
+	spin_lock_irqsave(&hvc->vc.lock, flags);
+	vd = mtk_hsdma_find_active_desc(c, cookie);
+	spin_unlock_irqrestore(&hvc->vc.lock, flags);
+
+	if (vd) {
+		hvd = to_hsdma_vdesc(vd);
+		bytes = hvd->residue;
+	}
+
+	dma_set_residue(txstate, bytes);
+
+	return ret;
+}
+
+static void mtk_hsdma_issue_pending(struct dma_chan *c)
+{
+	struct mtk_hsdma_device *hsdma = to_hsdma_dev(c);
+	struct mtk_hsdma_vchan *hvc = to_hsdma_vchan(c);
+	unsigned long flags;
+
+	spin_lock_irqsave(&hvc->vc.lock, flags);
+
+	if (vchan_issue_pending(&hvc->vc))
+		mtk_hsdma_issue_vchan_pending(hsdma, hvc);
+
+	spin_unlock_irqrestore(&hvc->vc.lock, flags);
+}
+
+static struct dma_async_tx_descriptor *
+mtk_hsdma_prep_dma_memcpy(struct dma_chan *c, dma_addr_t dest,
+			  dma_addr_t src, size_t len, unsigned long flags)
+{
+	struct mtk_hsdma_vdesc *hvd;
+
+	hvd = kzalloc(sizeof(*hvd), GFP_NOWAIT);
+	if (!hvd)
+		return NULL;
+
+	hvd->len = len;
+	hvd->residue = len;
+	hvd->src = src;
+	hvd->dest = dest;
+
+	return vchan_tx_prep(to_virt_chan(c), &hvd->vd, flags);
+}
+
+static int mtk_hsdma_free_inactive_desc(struct dma_chan *c)
+{
+	struct virt_dma_chan *vc = to_virt_chan(c);
+	unsigned long flags;
+	LIST_HEAD(head);
+
+	spin_lock_irqsave(&vc->lock, flags);
+	list_splice_tail_init(&vc->desc_allocated, &head);
+	list_splice_tail_init(&vc->desc_submitted, &head);
+	list_splice_tail_init(&vc->desc_issued, &head);
+	spin_unlock_irqrestore(&vc->lock, flags);
+
+	/* At the point, we don't expect users put descriptor into VC again */
+	vchan_dma_desc_free_list(vc, &head);
+
+	return 0;
+}
+
+static void mtk_hsdma_free_active_desc(struct dma_chan *c)
+{
+	struct mtk_hsdma_vchan *hvc = to_hsdma_vchan(c);
+	bool sync_needed = false;
+
+	/*
+	 * Once issue_synchronize is being set, which means once the hardware
+	 * consumes all descriptors for the channel in the ring, the
+	 * synchronization must be be notified immediately it is completed.
+	 */
+	spin_lock(&hvc->vc.lock);
+	if (!list_empty(&hvc->desc_hw_processing)) {
+		hvc->issue_synchronize = true;
+		sync_needed = true;
+	}
+	spin_unlock(&hvc->vc.lock);
+
+	if (sync_needed)
+		wait_for_completion(&hvc->issue_completion);
+	/*
+	 * At the point, we expect that all remaining descriptors in the ring
+	 * for the channel should be all processing done.
+	 */
+	WARN_ONCE(!list_empty(&hvc->desc_hw_processing),
+		  "Desc pending still in list desc_hw_processing\n");
+
+	/* Free all descriptors in list desc_completed */
+	vchan_synchronize(&hvc->vc);
+
+	WARN_ONCE(!list_empty(&hvc->vc.desc_completed),
+		  "Desc pending still in list desc_completed\n");
+}
+
+static int mtk_hsdma_terminate_all(struct dma_chan *c)
+{
+	/*
+	 * Free pending descriptors not processed yet by hardware that have
+	 * previously been submitted to the channel.
+	 */
+	mtk_hsdma_free_inactive_desc(c);
+
+	/*
+	 * However, the DMA engine doesn't provide any way to stop these
+	 * descriptors being processed currently by hardware. The only way is
+	 * to just waiting until these descriptors are all processed completely
+	 * through mtk_hsdma_free_active_desc call.
+	 */
+	mtk_hsdma_free_active_desc(c);
+
+	return 0;
+}
+
+static int mtk_hsdma_alloc_chan_resources(struct dma_chan *c)
+{
+	struct mtk_hsdma_device *hsdma = to_hsdma_dev(c);
+	int err;
+
+	/*
+	 * Since HSDMA has only one PC, the resource for PC is being allocated
+	 * when the first VC is being created and the other VCs would run on
+	 * the same PC.
+	 */
+	if (!refcount_read(&hsdma->pc_refcnt)) {
+		err = mtk_hsdma_alloc_pchan(hsdma, hsdma->pc);
+		if (err)
+			return err;
+		/*
+		 * refcount_inc would complain increment on 0; use-after-free.
+		 * Thus, we need to explicitly set it as 1 initially.
+		 */
+		refcount_set(&hsdma->pc_refcnt, 1);
+	} else {
+		refcount_inc(&hsdma->pc_refcnt);
+	}
+
+	return 0;
+}
+
+static void mtk_hsdma_free_chan_resources(struct dma_chan *c)
+{
+	struct mtk_hsdma_device *hsdma = to_hsdma_dev(c);
+
+	/* Free all descriptors in all lists on the VC */
+	mtk_hsdma_terminate_all(c);
+
+	/* The resource for PC is not freed until all the VCs are destroyed */
+	if (!refcount_dec_and_test(&hsdma->pc_refcnt))
+		return;
+
+	mtk_hsdma_free_pchan(hsdma, hsdma->pc);
+}
+
+static int mtk_hsdma_hw_init(struct mtk_hsdma_device *hsdma)
+{
+	int err;
+
+	pm_runtime_enable(hsdma2dev(hsdma));
+	pm_runtime_get_sync(hsdma2dev(hsdma));
+
+	err = clk_prepare_enable(hsdma->clk);
+	if (err)
+		return err;
+
+	mtk_dma_write(hsdma, MTK_HSDMA_INT_ENABLE, 0);
+	mtk_dma_write(hsdma, MTK_HSDMA_GLO, MTK_HSDMA_GLO_DEFAULT);
+
+	return 0;
+}
+
+static int mtk_hsdma_hw_deinit(struct mtk_hsdma_device *hsdma)
+{
+	mtk_dma_write(hsdma, MTK_HSDMA_GLO, 0);
+
+	clk_disable_unprepare(hsdma->clk);
+
+	pm_runtime_put_sync(hsdma2dev(hsdma));
+	pm_runtime_disable(hsdma2dev(hsdma));
+
+	return 0;
+}
+
+static const struct mtk_hsdma_soc mt7623_soc = {
+	.ddone = BIT(31),
+	.ls0 = BIT(30),
+};
+
+static const struct mtk_hsdma_soc mt7622_soc = {
+	.ddone = BIT(15),
+	.ls0 = BIT(14),
+};
+
+static const struct of_device_id mtk_hsdma_match[] = {
+	{ .compatible = "mediatek,mt7623-hsdma", .data = &mt7623_soc},
+	{ .compatible = "mediatek,mt7622-hsdma", .data = &mt7622_soc},
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, mtk_hsdma_match);
+
+static int mtk_hsdma_probe(struct platform_device *pdev)
+{
+	struct mtk_hsdma_device *hsdma;
+	struct mtk_hsdma_vchan *vc;
+	struct dma_device *dd;
+	struct resource *res;
+	int i, err;
+
+	hsdma = devm_kzalloc(&pdev->dev, sizeof(*hsdma), GFP_KERNEL);
+	if (!hsdma)
+		return -ENOMEM;
+
+	dd = &hsdma->ddev;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	hsdma->base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(hsdma->base))
+		return PTR_ERR(hsdma->base);
+
+	hsdma->soc = of_device_get_match_data(&pdev->dev);
+	if (!hsdma->soc) {
+		dev_err(&pdev->dev, "No device match found\n");
+		return -ENODEV;
+	}
+
+	hsdma->clk = devm_clk_get(&pdev->dev, "hsdma");
+	if (IS_ERR(hsdma->clk)) {
+		dev_err(&pdev->dev, "No clock for %s\n",
+			dev_name(&pdev->dev));
+		return PTR_ERR(hsdma->clk);
+	}
+
+	res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
+	if (!res) {
+		dev_err(&pdev->dev, "No irq resource for %s\n",
+			dev_name(&pdev->dev));
+		return -EINVAL;
+	}
+	hsdma->irq = res->start;
+
+	refcount_set(&hsdma->pc_refcnt, 0);
+	spin_lock_init(&hsdma->lock);
+
+	dma_cap_set(DMA_MEMCPY, dd->cap_mask);
+
+	dd->copy_align = MTK_HSDMA_ALIGN_SIZE;
+	dd->device_alloc_chan_resources = mtk_hsdma_alloc_chan_resources;
+	dd->device_free_chan_resources = mtk_hsdma_free_chan_resources;
+	dd->device_tx_status = mtk_hsdma_tx_status;
+	dd->device_issue_pending = mtk_hsdma_issue_pending;
+	dd->device_prep_dma_memcpy = mtk_hsdma_prep_dma_memcpy;
+	dd->device_terminate_all = mtk_hsdma_terminate_all;
+	dd->src_addr_widths = MTK_HSDMA_DMA_BUSWIDTHS;
+	dd->dst_addr_widths = MTK_HSDMA_DMA_BUSWIDTHS;
+	dd->directions = BIT(DMA_MEM_TO_MEM);
+	dd->residue_granularity = DMA_RESIDUE_GRANULARITY_SEGMENT;
+	dd->dev = &pdev->dev;
+	INIT_LIST_HEAD(&dd->channels);
+
+	hsdma->dma_requests = MTK_HSDMA_NR_VCHANS;
+	if (pdev->dev.of_node && of_property_read_u32(pdev->dev.of_node,
+						      "dma-requests",
+						      &hsdma->dma_requests)) {
+		dev_info(&pdev->dev,
+			 "Using %u as missing dma-requests property\n",
+			 MTK_HSDMA_NR_VCHANS);
+	}
+
+	hsdma->pc = devm_kcalloc(&pdev->dev, MTK_HSDMA_NR_MAX_PCHANS,
+				 sizeof(*hsdma->pc), GFP_KERNEL);
+	if (!hsdma->pc)
+		return -ENOMEM;
+
+	hsdma->vc = devm_kcalloc(&pdev->dev, hsdma->dma_requests,
+				 sizeof(*hsdma->vc), GFP_KERNEL);
+	if (!hsdma->vc)
+		return -ENOMEM;
+
+	for (i = 0; i < hsdma->dma_requests; i++) {
+		vc = &hsdma->vc[i];
+		vc->vc.desc_free = mtk_hsdma_vdesc_free;
+		vchan_init(&vc->vc, dd);
+		init_completion(&vc->issue_completion);
+		INIT_LIST_HEAD(&vc->desc_hw_processing);
+	}
+
+	err = dma_async_device_register(dd);
+	if (err)
+		return err;
+
+	err = of_dma_controller_register(pdev->dev.of_node,
+					 of_dma_xlate_by_chan_id, hsdma);
+	if (err) {
+		dev_err(&pdev->dev,
+			"MediaTek HSDMA OF registration failed %d\n", err);
+		goto err_unregister;
+	}
+
+	mtk_hsdma_hw_init(hsdma);
+
+	err = devm_request_irq(&pdev->dev, hsdma->irq,
+			       mtk_hsdma_irq, 0,
+			       dev_name(&pdev->dev), hsdma);
+	if (err) {
+		dev_err(&pdev->dev,
+			"request_irq failed with err %d\n", err);
+		goto err_free;
+	}
+
+	platform_set_drvdata(pdev, hsdma);
+
+	dev_info(&pdev->dev, "MediaTek HSDMA driver registered\n");
+
+	return 0;
+
+err_free:
+	mtk_hsdma_hw_deinit(hsdma);
+	of_dma_controller_free(pdev->dev.of_node);
+err_unregister:
+	dma_async_device_unregister(dd);
+
+	return err;
+}
+
+static int mtk_hsdma_remove(struct platform_device *pdev)
+{
+	struct mtk_hsdma_device *hsdma = platform_get_drvdata(pdev);
+	struct mtk_hsdma_vchan *vc;
+	int i;
+
+	/* Kill VC task */
+	for (i = 0; i < hsdma->dma_requests; i++) {
+		vc = &hsdma->vc[i];
+
+		list_del(&vc->vc.chan.device_node);
+		tasklet_kill(&vc->vc.task);
+	}
+
+	/* Disable DMA interrupt */
+	mtk_dma_write(hsdma, MTK_HSDMA_INT_ENABLE, 0);
+
+	/* Waits for any pending IRQ handlers to complete */
+	synchronize_irq(hsdma->irq);
+
+	/* Disable hardware */
+	mtk_hsdma_hw_deinit(hsdma);
+
+	dma_async_device_unregister(&hsdma->ddev);
+	of_dma_controller_free(pdev->dev.of_node);
+
+	return 0;
+}
+
+static struct platform_driver mtk_hsdma_driver = {
+	.probe		= mtk_hsdma_probe,
+	.remove		= mtk_hsdma_remove,
+	.driver = {
+		.name		= KBUILD_MODNAME,
+		.of_match_table	= mtk_hsdma_match,
+	},
+};
+module_platform_driver(mtk_hsdma_driver);
+
+MODULE_DESCRIPTION("MediaTek High-Speed DMA Controller Driver");
+MODULE_AUTHOR("Sean Wang <sean.wang@mediatek.com>");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/dma/mediatek/mtk-uart-apdma.c b/drivers/dma/mediatek/mtk-uart-apdma.c
new file mode 100644
index 000000000..0acf6a92a
--- /dev/null
+++ b/drivers/dma/mediatek/mtk-uart-apdma.c
@@ -0,0 +1,656 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * MediaTek UART APDMA driver.
+ *
+ * Copyright (c) 2019 MediaTek Inc.
+ * Author: Long Cheng <long.cheng@mediatek.com>
+ */
+
+#include <linux/clk.h>
+#include <linux/dmaengine.h>
+#include <linux/dma-mapping.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/iopoll.h>
+#include <linux/kernel.h>
+#include <linux/list.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/of_dma.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+
+#include "../virt-dma.h"
+
+/* The default number of virtual channel */
+#define MTK_UART_APDMA_NR_VCHANS	8
+
+#define VFF_EN_B		BIT(0)
+#define VFF_STOP_B		BIT(0)
+#define VFF_FLUSH_B		BIT(0)
+#define VFF_4G_EN_B		BIT(0)
+/* rx valid size >=  vff thre */
+#define VFF_RX_INT_EN_B		(BIT(0) | BIT(1))
+/* tx left size >= vff thre */
+#define VFF_TX_INT_EN_B		BIT(0)
+#define VFF_WARM_RST_B		BIT(0)
+#define VFF_RX_INT_CLR_B	(BIT(0) | BIT(1))
+#define VFF_TX_INT_CLR_B	0
+#define VFF_STOP_CLR_B		0
+#define VFF_EN_CLR_B		0
+#define VFF_INT_EN_CLR_B	0
+#define VFF_4G_SUPPORT_CLR_B	0
+
+/*
+ * interrupt trigger level for tx
+ * if threshold is n, no polling is required to start tx.
+ * otherwise need polling VFF_FLUSH.
+ */
+#define VFF_TX_THRE(n)		(n)
+/* interrupt trigger level for rx */
+#define VFF_RX_THRE(n)		((n) * 3 / 4)
+
+#define VFF_RING_SIZE	0xffff
+/* invert this bit when wrap ring head again */
+#define VFF_RING_WRAP	0x10000
+
+#define VFF_INT_FLAG		0x00
+#define VFF_INT_EN		0x04
+#define VFF_EN			0x08
+#define VFF_RST			0x0c
+#define VFF_STOP		0x10
+#define VFF_FLUSH		0x14
+#define VFF_ADDR		0x1c
+#define VFF_LEN			0x24
+#define VFF_THRE		0x28
+#define VFF_WPT			0x2c
+#define VFF_RPT			0x30
+/* TX: the buffer size HW can read. RX: the buffer size SW can read. */
+#define VFF_VALID_SIZE		0x3c
+/* TX: the buffer size SW can write. RX: the buffer size HW can write. */
+#define VFF_LEFT_SIZE		0x40
+#define VFF_DEBUG_STATUS	0x50
+#define VFF_4G_SUPPORT		0x54
+
+struct mtk_uart_apdmadev {
+	struct dma_device ddev;
+	struct clk *clk;
+	bool support_33bits;
+	unsigned int dma_requests;
+};
+
+struct mtk_uart_apdma_desc {
+	struct virt_dma_desc vd;
+
+	dma_addr_t addr;
+	unsigned int avail_len;
+};
+
+struct mtk_chan {
+	struct virt_dma_chan vc;
+	struct dma_slave_config	cfg;
+	struct mtk_uart_apdma_desc *desc;
+	enum dma_transfer_direction dir;
+
+	void __iomem *base;
+	unsigned int irq;
+
+	unsigned int rx_status;
+};
+
+static inline struct mtk_uart_apdmadev *
+to_mtk_uart_apdma_dev(struct dma_device *d)
+{
+	return container_of(d, struct mtk_uart_apdmadev, ddev);
+}
+
+static inline struct mtk_chan *to_mtk_uart_apdma_chan(struct dma_chan *c)
+{
+	return container_of(c, struct mtk_chan, vc.chan);
+}
+
+static inline struct mtk_uart_apdma_desc *to_mtk_uart_apdma_desc
+	(struct dma_async_tx_descriptor *t)
+{
+	return container_of(t, struct mtk_uart_apdma_desc, vd.tx);
+}
+
+static void mtk_uart_apdma_write(struct mtk_chan *c,
+			       unsigned int reg, unsigned int val)
+{
+	writel(val, c->base + reg);
+}
+
+static unsigned int mtk_uart_apdma_read(struct mtk_chan *c, unsigned int reg)
+{
+	return readl(c->base + reg);
+}
+
+static void mtk_uart_apdma_desc_free(struct virt_dma_desc *vd)
+{
+	kfree(container_of(vd, struct mtk_uart_apdma_desc, vd));
+}
+
+static void mtk_uart_apdma_start_tx(struct mtk_chan *c)
+{
+	struct mtk_uart_apdmadev *mtkd =
+				to_mtk_uart_apdma_dev(c->vc.chan.device);
+	struct mtk_uart_apdma_desc *d = c->desc;
+	unsigned int wpt, vff_sz;
+
+	vff_sz = c->cfg.dst_port_window_size;
+	if (!mtk_uart_apdma_read(c, VFF_LEN)) {
+		mtk_uart_apdma_write(c, VFF_ADDR, d->addr);
+		mtk_uart_apdma_write(c, VFF_LEN, vff_sz);
+		mtk_uart_apdma_write(c, VFF_THRE, VFF_TX_THRE(vff_sz));
+		mtk_uart_apdma_write(c, VFF_WPT, 0);
+		mtk_uart_apdma_write(c, VFF_INT_FLAG, VFF_TX_INT_CLR_B);
+
+		if (mtkd->support_33bits)
+			mtk_uart_apdma_write(c, VFF_4G_SUPPORT, VFF_4G_EN_B);
+	}
+
+	mtk_uart_apdma_write(c, VFF_EN, VFF_EN_B);
+	if (mtk_uart_apdma_read(c, VFF_EN) != VFF_EN_B)
+		dev_err(c->vc.chan.device->dev, "Enable TX fail\n");
+
+	if (!mtk_uart_apdma_read(c, VFF_LEFT_SIZE)) {
+		mtk_uart_apdma_write(c, VFF_INT_EN, VFF_TX_INT_EN_B);
+		return;
+	}
+
+	wpt = mtk_uart_apdma_read(c, VFF_WPT);
+
+	wpt += c->desc->avail_len;
+	if ((wpt & VFF_RING_SIZE) == vff_sz)
+		wpt = (wpt & VFF_RING_WRAP) ^ VFF_RING_WRAP;
+
+	/* Let DMA start moving data */
+	mtk_uart_apdma_write(c, VFF_WPT, wpt);
+
+	/* HW auto set to 0 when left size >= threshold */
+	mtk_uart_apdma_write(c, VFF_INT_EN, VFF_TX_INT_EN_B);
+	if (!mtk_uart_apdma_read(c, VFF_FLUSH))
+		mtk_uart_apdma_write(c, VFF_FLUSH, VFF_FLUSH_B);
+}
+
+static void mtk_uart_apdma_start_rx(struct mtk_chan *c)
+{
+	struct mtk_uart_apdmadev *mtkd =
+				to_mtk_uart_apdma_dev(c->vc.chan.device);
+	struct mtk_uart_apdma_desc *d = c->desc;
+	unsigned int vff_sz;
+
+	vff_sz = c->cfg.src_port_window_size;
+	if (!mtk_uart_apdma_read(c, VFF_LEN)) {
+		mtk_uart_apdma_write(c, VFF_ADDR, d->addr);
+		mtk_uart_apdma_write(c, VFF_LEN, vff_sz);
+		mtk_uart_apdma_write(c, VFF_THRE, VFF_RX_THRE(vff_sz));
+		mtk_uart_apdma_write(c, VFF_RPT, 0);
+		mtk_uart_apdma_write(c, VFF_INT_FLAG, VFF_RX_INT_CLR_B);
+
+		if (mtkd->support_33bits)
+			mtk_uart_apdma_write(c, VFF_4G_SUPPORT, VFF_4G_EN_B);
+	}
+
+	mtk_uart_apdma_write(c, VFF_INT_EN, VFF_RX_INT_EN_B);
+	mtk_uart_apdma_write(c, VFF_EN, VFF_EN_B);
+	if (mtk_uart_apdma_read(c, VFF_EN) != VFF_EN_B)
+		dev_err(c->vc.chan.device->dev, "Enable RX fail\n");
+}
+
+static void mtk_uart_apdma_tx_handler(struct mtk_chan *c)
+{
+	mtk_uart_apdma_write(c, VFF_INT_FLAG, VFF_TX_INT_CLR_B);
+	mtk_uart_apdma_write(c, VFF_INT_EN, VFF_INT_EN_CLR_B);
+	mtk_uart_apdma_write(c, VFF_EN, VFF_EN_CLR_B);
+}
+
+static void mtk_uart_apdma_rx_handler(struct mtk_chan *c)
+{
+	struct mtk_uart_apdma_desc *d = c->desc;
+	unsigned int len, wg, rg;
+	int cnt;
+
+	mtk_uart_apdma_write(c, VFF_INT_FLAG, VFF_RX_INT_CLR_B);
+
+	if (!mtk_uart_apdma_read(c, VFF_VALID_SIZE))
+		return;
+
+	mtk_uart_apdma_write(c, VFF_EN, VFF_EN_CLR_B);
+	mtk_uart_apdma_write(c, VFF_INT_EN, VFF_INT_EN_CLR_B);
+
+	len = c->cfg.src_port_window_size;
+	rg = mtk_uart_apdma_read(c, VFF_RPT);
+	wg = mtk_uart_apdma_read(c, VFF_WPT);
+	cnt = (wg & VFF_RING_SIZE) - (rg & VFF_RING_SIZE);
+
+	/*
+	 * The buffer is ring buffer. If wrap bit different,
+	 * represents the start of the next cycle for WPT
+	 */
+	if ((rg ^ wg) & VFF_RING_WRAP)
+		cnt += len;
+
+	c->rx_status = d->avail_len - cnt;
+	mtk_uart_apdma_write(c, VFF_RPT, wg);
+}
+
+static void mtk_uart_apdma_chan_complete_handler(struct mtk_chan *c)
+{
+	struct mtk_uart_apdma_desc *d = c->desc;
+
+	if (d) {
+		list_del(&d->vd.node);
+		vchan_cookie_complete(&d->vd);
+		c->desc = NULL;
+	}
+}
+
+static irqreturn_t mtk_uart_apdma_irq_handler(int irq, void *dev_id)
+{
+	struct dma_chan *chan = (struct dma_chan *)dev_id;
+	struct mtk_chan *c = to_mtk_uart_apdma_chan(chan);
+	unsigned long flags;
+
+	spin_lock_irqsave(&c->vc.lock, flags);
+	if (c->dir == DMA_DEV_TO_MEM)
+		mtk_uart_apdma_rx_handler(c);
+	else if (c->dir == DMA_MEM_TO_DEV)
+		mtk_uart_apdma_tx_handler(c);
+	mtk_uart_apdma_chan_complete_handler(c);
+	spin_unlock_irqrestore(&c->vc.lock, flags);
+
+	return IRQ_HANDLED;
+}
+
+static int mtk_uart_apdma_alloc_chan_resources(struct dma_chan *chan)
+{
+	struct mtk_uart_apdmadev *mtkd = to_mtk_uart_apdma_dev(chan->device);
+	struct mtk_chan *c = to_mtk_uart_apdma_chan(chan);
+	unsigned int status;
+	int ret;
+
+	ret = pm_runtime_resume_and_get(mtkd->ddev.dev);
+	if (ret < 0) {
+		pm_runtime_put_noidle(chan->device->dev);
+		return ret;
+	}
+
+	mtk_uart_apdma_write(c, VFF_ADDR, 0);
+	mtk_uart_apdma_write(c, VFF_THRE, 0);
+	mtk_uart_apdma_write(c, VFF_LEN, 0);
+	mtk_uart_apdma_write(c, VFF_RST, VFF_WARM_RST_B);
+
+	ret = readx_poll_timeout(readl, c->base + VFF_EN,
+			  status, !status, 10, 100);
+	if (ret)
+		goto err_pm;
+
+	ret = request_irq(c->irq, mtk_uart_apdma_irq_handler,
+			  IRQF_TRIGGER_NONE, KBUILD_MODNAME, chan);
+	if (ret < 0) {
+		dev_err(chan->device->dev, "Can't request dma IRQ\n");
+		ret = -EINVAL;
+		goto err_pm;
+	}
+
+	if (mtkd->support_33bits)
+		mtk_uart_apdma_write(c, VFF_4G_SUPPORT, VFF_4G_SUPPORT_CLR_B);
+
+err_pm:
+	pm_runtime_put_noidle(mtkd->ddev.dev);
+	return ret;
+}
+
+static void mtk_uart_apdma_free_chan_resources(struct dma_chan *chan)
+{
+	struct mtk_uart_apdmadev *mtkd = to_mtk_uart_apdma_dev(chan->device);
+	struct mtk_chan *c = to_mtk_uart_apdma_chan(chan);
+
+	free_irq(c->irq, chan);
+
+	tasklet_kill(&c->vc.task);
+
+	vchan_free_chan_resources(&c->vc);
+
+	pm_runtime_put_sync(mtkd->ddev.dev);
+}
+
+static enum dma_status mtk_uart_apdma_tx_status(struct dma_chan *chan,
+					 dma_cookie_t cookie,
+					 struct dma_tx_state *txstate)
+{
+	struct mtk_chan *c = to_mtk_uart_apdma_chan(chan);
+	enum dma_status ret;
+
+	ret = dma_cookie_status(chan, cookie, txstate);
+	if (!txstate)
+		return ret;
+
+	dma_set_residue(txstate, c->rx_status);
+
+	return ret;
+}
+
+/*
+ * dmaengine_prep_slave_single will call the function. and sglen is 1.
+ * 8250 uart using one ring buffer, and deal with one sg.
+ */
+static struct dma_async_tx_descriptor *mtk_uart_apdma_prep_slave_sg
+	(struct dma_chan *chan, struct scatterlist *sgl,
+	unsigned int sglen, enum dma_transfer_direction dir,
+	unsigned long tx_flags, void *context)
+{
+	struct mtk_chan *c = to_mtk_uart_apdma_chan(chan);
+	struct mtk_uart_apdma_desc *d;
+
+	if (!is_slave_direction(dir) || sglen != 1)
+		return NULL;
+
+	/* Now allocate and setup the descriptor */
+	d = kzalloc(sizeof(*d), GFP_NOWAIT);
+	if (!d)
+		return NULL;
+
+	d->avail_len = sg_dma_len(sgl);
+	d->addr = sg_dma_address(sgl);
+	c->dir = dir;
+
+	return vchan_tx_prep(&c->vc, &d->vd, tx_flags);
+}
+
+static void mtk_uart_apdma_issue_pending(struct dma_chan *chan)
+{
+	struct mtk_chan *c = to_mtk_uart_apdma_chan(chan);
+	struct virt_dma_desc *vd;
+	unsigned long flags;
+
+	spin_lock_irqsave(&c->vc.lock, flags);
+	if (vchan_issue_pending(&c->vc) && !c->desc) {
+		vd = vchan_next_desc(&c->vc);
+		c->desc = to_mtk_uart_apdma_desc(&vd->tx);
+
+		if (c->dir == DMA_DEV_TO_MEM)
+			mtk_uart_apdma_start_rx(c);
+		else if (c->dir == DMA_MEM_TO_DEV)
+			mtk_uart_apdma_start_tx(c);
+	}
+
+	spin_unlock_irqrestore(&c->vc.lock, flags);
+}
+
+static int mtk_uart_apdma_slave_config(struct dma_chan *chan,
+				   struct dma_slave_config *config)
+{
+	struct mtk_chan *c = to_mtk_uart_apdma_chan(chan);
+
+	memcpy(&c->cfg, config, sizeof(*config));
+
+	return 0;
+}
+
+static int mtk_uart_apdma_terminate_all(struct dma_chan *chan)
+{
+	struct mtk_chan *c = to_mtk_uart_apdma_chan(chan);
+	unsigned long flags;
+	unsigned int status;
+	LIST_HEAD(head);
+	int ret;
+
+	mtk_uart_apdma_write(c, VFF_FLUSH, VFF_FLUSH_B);
+
+	ret = readx_poll_timeout(readl, c->base + VFF_FLUSH,
+			  status, status != VFF_FLUSH_B, 10, 100);
+	if (ret)
+		dev_err(c->vc.chan.device->dev, "flush: fail, status=0x%x\n",
+			mtk_uart_apdma_read(c, VFF_DEBUG_STATUS));
+
+	/*
+	 * Stop need 3 steps.
+	 * 1. set stop to 1
+	 * 2. wait en to 0
+	 * 3. set stop as 0
+	 */
+	mtk_uart_apdma_write(c, VFF_STOP, VFF_STOP_B);
+	ret = readx_poll_timeout(readl, c->base + VFF_EN,
+			  status, !status, 10, 100);
+	if (ret)
+		dev_err(c->vc.chan.device->dev, "stop: fail, status=0x%x\n",
+			mtk_uart_apdma_read(c, VFF_DEBUG_STATUS));
+
+	mtk_uart_apdma_write(c, VFF_STOP, VFF_STOP_CLR_B);
+	mtk_uart_apdma_write(c, VFF_INT_EN, VFF_INT_EN_CLR_B);
+
+	if (c->dir == DMA_DEV_TO_MEM)
+		mtk_uart_apdma_write(c, VFF_INT_FLAG, VFF_RX_INT_CLR_B);
+	else if (c->dir == DMA_MEM_TO_DEV)
+		mtk_uart_apdma_write(c, VFF_INT_FLAG, VFF_TX_INT_CLR_B);
+
+	synchronize_irq(c->irq);
+
+	spin_lock_irqsave(&c->vc.lock, flags);
+	vchan_get_all_descriptors(&c->vc, &head);
+	spin_unlock_irqrestore(&c->vc.lock, flags);
+
+	vchan_dma_desc_free_list(&c->vc, &head);
+
+	return 0;
+}
+
+static int mtk_uart_apdma_device_pause(struct dma_chan *chan)
+{
+	struct mtk_chan *c = to_mtk_uart_apdma_chan(chan);
+	unsigned long flags;
+
+	spin_lock_irqsave(&c->vc.lock, flags);
+
+	mtk_uart_apdma_write(c, VFF_EN, VFF_EN_CLR_B);
+	mtk_uart_apdma_write(c, VFF_INT_EN, VFF_INT_EN_CLR_B);
+
+	spin_unlock_irqrestore(&c->vc.lock, flags);
+	synchronize_irq(c->irq);
+
+	return 0;
+}
+
+static void mtk_uart_apdma_free(struct mtk_uart_apdmadev *mtkd)
+{
+	while (!list_empty(&mtkd->ddev.channels)) {
+		struct mtk_chan *c = list_first_entry(&mtkd->ddev.channels,
+			struct mtk_chan, vc.chan.device_node);
+
+		list_del(&c->vc.chan.device_node);
+		tasklet_kill(&c->vc.task);
+	}
+}
+
+static const struct of_device_id mtk_uart_apdma_match[] = {
+	{ .compatible = "mediatek,mt6577-uart-dma", },
+	{ /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(of, mtk_uart_apdma_match);
+
+static int mtk_uart_apdma_probe(struct platform_device *pdev)
+{
+	struct device_node *np = pdev->dev.of_node;
+	struct mtk_uart_apdmadev *mtkd;
+	int bit_mask = 32, rc;
+	struct mtk_chan *c;
+	unsigned int i;
+
+	mtkd = devm_kzalloc(&pdev->dev, sizeof(*mtkd), GFP_KERNEL);
+	if (!mtkd)
+		return -ENOMEM;
+
+	mtkd->clk = devm_clk_get(&pdev->dev, NULL);
+	if (IS_ERR(mtkd->clk)) {
+		dev_err(&pdev->dev, "No clock specified\n");
+		rc = PTR_ERR(mtkd->clk);
+		return rc;
+	}
+
+	if (of_property_read_bool(np, "mediatek,dma-33bits"))
+		mtkd->support_33bits = true;
+
+	if (mtkd->support_33bits)
+		bit_mask = 33;
+
+	rc = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(bit_mask));
+	if (rc)
+		return rc;
+
+	dma_cap_set(DMA_SLAVE, mtkd->ddev.cap_mask);
+	mtkd->ddev.device_alloc_chan_resources =
+				mtk_uart_apdma_alloc_chan_resources;
+	mtkd->ddev.device_free_chan_resources =
+				mtk_uart_apdma_free_chan_resources;
+	mtkd->ddev.device_tx_status = mtk_uart_apdma_tx_status;
+	mtkd->ddev.device_issue_pending = mtk_uart_apdma_issue_pending;
+	mtkd->ddev.device_prep_slave_sg = mtk_uart_apdma_prep_slave_sg;
+	mtkd->ddev.device_config = mtk_uart_apdma_slave_config;
+	mtkd->ddev.device_pause = mtk_uart_apdma_device_pause;
+	mtkd->ddev.device_terminate_all = mtk_uart_apdma_terminate_all;
+	mtkd->ddev.src_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_1_BYTE);
+	mtkd->ddev.dst_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_1_BYTE);
+	mtkd->ddev.directions = BIT(DMA_DEV_TO_MEM) | BIT(DMA_MEM_TO_DEV);
+	mtkd->ddev.residue_granularity = DMA_RESIDUE_GRANULARITY_SEGMENT;
+	mtkd->ddev.dev = &pdev->dev;
+	INIT_LIST_HEAD(&mtkd->ddev.channels);
+
+	mtkd->dma_requests = MTK_UART_APDMA_NR_VCHANS;
+	if (of_property_read_u32(np, "dma-requests", &mtkd->dma_requests)) {
+		dev_info(&pdev->dev,
+			 "Using %u as missing dma-requests property\n",
+			 MTK_UART_APDMA_NR_VCHANS);
+	}
+
+	for (i = 0; i < mtkd->dma_requests; i++) {
+		c = devm_kzalloc(mtkd->ddev.dev, sizeof(*c), GFP_KERNEL);
+		if (!c) {
+			rc = -ENODEV;
+			goto err_no_dma;
+		}
+
+		c->base = devm_platform_ioremap_resource(pdev, i);
+		if (IS_ERR(c->base)) {
+			rc = PTR_ERR(c->base);
+			goto err_no_dma;
+		}
+		c->vc.desc_free = mtk_uart_apdma_desc_free;
+		vchan_init(&c->vc, &mtkd->ddev);
+
+		rc = platform_get_irq(pdev, i);
+		if (rc < 0)
+			goto err_no_dma;
+		c->irq = rc;
+	}
+
+	pm_runtime_enable(&pdev->dev);
+	pm_runtime_set_active(&pdev->dev);
+
+	rc = dma_async_device_register(&mtkd->ddev);
+	if (rc)
+		goto rpm_disable;
+
+	platform_set_drvdata(pdev, mtkd);
+
+	/* Device-tree DMA controller registration */
+	rc = of_dma_controller_register(np, of_dma_xlate_by_chan_id, mtkd);
+	if (rc)
+		goto dma_remove;
+
+	return rc;
+
+dma_remove:
+	dma_async_device_unregister(&mtkd->ddev);
+rpm_disable:
+	pm_runtime_disable(&pdev->dev);
+err_no_dma:
+	mtk_uart_apdma_free(mtkd);
+	return rc;
+}
+
+static int mtk_uart_apdma_remove(struct platform_device *pdev)
+{
+	struct mtk_uart_apdmadev *mtkd = platform_get_drvdata(pdev);
+
+	of_dma_controller_free(pdev->dev.of_node);
+
+	mtk_uart_apdma_free(mtkd);
+
+	dma_async_device_unregister(&mtkd->ddev);
+
+	pm_runtime_disable(&pdev->dev);
+
+	return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int mtk_uart_apdma_suspend(struct device *dev)
+{
+	struct mtk_uart_apdmadev *mtkd = dev_get_drvdata(dev);
+
+	if (!pm_runtime_suspended(dev))
+		clk_disable_unprepare(mtkd->clk);
+
+	return 0;
+}
+
+static int mtk_uart_apdma_resume(struct device *dev)
+{
+	int ret;
+	struct mtk_uart_apdmadev *mtkd = dev_get_drvdata(dev);
+
+	if (!pm_runtime_suspended(dev)) {
+		ret = clk_prepare_enable(mtkd->clk);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+#endif /* CONFIG_PM_SLEEP */
+
+#ifdef CONFIG_PM
+static int mtk_uart_apdma_runtime_suspend(struct device *dev)
+{
+	struct mtk_uart_apdmadev *mtkd = dev_get_drvdata(dev);
+
+	clk_disable_unprepare(mtkd->clk);
+
+	return 0;
+}
+
+static int mtk_uart_apdma_runtime_resume(struct device *dev)
+{
+	struct mtk_uart_apdmadev *mtkd = dev_get_drvdata(dev);
+
+	return clk_prepare_enable(mtkd->clk);
+}
+#endif /* CONFIG_PM */
+
+static const struct dev_pm_ops mtk_uart_apdma_pm_ops = {
+	SET_SYSTEM_SLEEP_PM_OPS(mtk_uart_apdma_suspend, mtk_uart_apdma_resume)
+	SET_RUNTIME_PM_OPS(mtk_uart_apdma_runtime_suspend,
+			   mtk_uart_apdma_runtime_resume, NULL)
+};
+
+static struct platform_driver mtk_uart_apdma_driver = {
+	.probe	= mtk_uart_apdma_probe,
+	.remove	= mtk_uart_apdma_remove,
+	.driver = {
+		.name		= KBUILD_MODNAME,
+		.pm		= &mtk_uart_apdma_pm_ops,
+		.of_match_table = of_match_ptr(mtk_uart_apdma_match),
+	},
+};
+
+module_platform_driver(mtk_uart_apdma_driver);
+
+MODULE_DESCRIPTION("MediaTek UART APDMA Controller Driver");
+MODULE_AUTHOR("Long Cheng <long.cheng@mediatek.com>");
+MODULE_LICENSE("GPL v2");