dmaengine: Add Xilinx zynqmp dma engine driver support

Added the driver for zynqmp dma engine used in Zynq
UltraScale+ MPSoC. This dma controller supports memory to memory
and I/O to I/O buffer transfers.

Signed-off-by: Kedareswara rao Appana <appanad@xilinx.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

2 files changed, 1146 insertions, 0 deletions

diff --git a/drivers/dma/xilinx/Makefile b/drivers/dma/xilinx/Makefile
index af9e69a41f8f..9e91f8f5b087 100644
--- a/drivers/dma/xilinx/Makefile
+++ b/drivers/dma/xilinx/Makefile
@@ -1 +1,2 @@
 obj-$(CONFIG_XILINX_DMA) += xilinx_dma.o
+obj-$(CONFIG_XILINX_ZYNQMP_DMA) += zynqmp_dma.o
diff --git a/drivers/dma/xilinx/zynqmp_dma.c b/drivers/dma/xilinx/zynqmp_dma.c
new file mode 100644
index 000000000000..59bc1f730a48
--- /dev/null
+++ b/drivers/dma/xilinx/zynqmp_dma.c
@@ -0,0 +1,1145 @@
+/*
+ * DMA driver for Xilinx ZynqMP DMA Engine
+ *
+ * Copyright (C) 2016 Xilinx, Inc. All rights reserved.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#include <linux/bitops.h>
+#include <linux/dmapool.h>
+#include <linux/dma/xilinx_dma.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of_address.h>
+#include <linux/of_dma.h>
+#include <linux/of_irq.h>
+#include <linux/of_platform.h>
+#include <linux/slab.h>
+#include <linux/clk.h>
+#include <linux/io-64-nonatomic-lo-hi.h>
+
+#include "../dmaengine.h"
+
+/* Register Offsets */
+#define ZYNQMP_DMA_ISR			0x100
+#define ZYNQMP_DMA_IMR			0x104
+#define ZYNQMP_DMA_IER			0x108
+#define ZYNQMP_DMA_IDS			0x10C
+#define ZYNQMP_DMA_CTRL0		0x110
+#define ZYNQMP_DMA_CTRL1		0x114
+#define ZYNQMP_DMA_DATA_ATTR		0x120
+#define ZYNQMP_DMA_DSCR_ATTR		0x124
+#define ZYNQMP_DMA_SRC_DSCR_WRD0	0x128
+#define ZYNQMP_DMA_SRC_DSCR_WRD1	0x12C
+#define ZYNQMP_DMA_SRC_DSCR_WRD2	0x130
+#define ZYNQMP_DMA_SRC_DSCR_WRD3	0x134
+#define ZYNQMP_DMA_DST_DSCR_WRD0	0x138
+#define ZYNQMP_DMA_DST_DSCR_WRD1	0x13C
+#define ZYNQMP_DMA_DST_DSCR_WRD2	0x140
+#define ZYNQMP_DMA_DST_DSCR_WRD3	0x144
+#define ZYNQMP_DMA_SRC_START_LSB	0x158
+#define ZYNQMP_DMA_SRC_START_MSB	0x15C
+#define ZYNQMP_DMA_DST_START_LSB	0x160
+#define ZYNQMP_DMA_DST_START_MSB	0x164
+#define ZYNQMP_DMA_RATE_CTRL		0x18C
+#define ZYNQMP_DMA_IRQ_SRC_ACCT		0x190
+#define ZYNQMP_DMA_IRQ_DST_ACCT		0x194
+#define ZYNQMP_DMA_CTRL2		0x200
+
+/* Interrupt registers bit field definitions */
+#define ZYNQMP_DMA_DONE			BIT(10)
+#define ZYNQMP_DMA_AXI_WR_DATA		BIT(9)
+#define ZYNQMP_DMA_AXI_RD_DATA		BIT(8)
+#define ZYNQMP_DMA_AXI_RD_DST_DSCR	BIT(7)
+#define ZYNQMP_DMA_AXI_RD_SRC_DSCR	BIT(6)
+#define ZYNQMP_DMA_IRQ_DST_ACCT_ERR	BIT(5)
+#define ZYNQMP_DMA_IRQ_SRC_ACCT_ERR	BIT(4)
+#define ZYNQMP_DMA_BYTE_CNT_OVRFL	BIT(3)
+#define ZYNQMP_DMA_DST_DSCR_DONE	BIT(2)
+#define ZYNQMP_DMA_INV_APB		BIT(0)
+
+/* Control 0 register bit field definitions */
+#define ZYNQMP_DMA_OVR_FETCH		BIT(7)
+#define ZYNQMP_DMA_POINT_TYPE_SG	BIT(6)
+#define ZYNQMP_DMA_RATE_CTRL_EN		BIT(3)
+
+/* Control 1 register bit field definitions */
+#define ZYNQMP_DMA_SRC_ISSUE		GENMASK(4, 0)
+
+/* Data Attribute register bit field definitions */
+#define ZYNQMP_DMA_ARBURST		GENMASK(27, 26)
+#define ZYNQMP_DMA_ARCACHE		GENMASK(25, 22)
+#define ZYNQMP_DMA_ARCACHE_OFST		22
+#define ZYNQMP_DMA_ARQOS		GENMASK(21, 18)
+#define ZYNQMP_DMA_ARQOS_OFST		18
+#define ZYNQMP_DMA_ARLEN		GENMASK(17, 14)
+#define ZYNQMP_DMA_ARLEN_OFST		14
+#define ZYNQMP_DMA_AWBURST		GENMASK(13, 12)
+#define ZYNQMP_DMA_AWCACHE		GENMASK(11, 8)
+#define ZYNQMP_DMA_AWCACHE_OFST		8
+#define ZYNQMP_DMA_AWQOS		GENMASK(7, 4)
+#define ZYNQMP_DMA_AWQOS_OFST		4
+#define ZYNQMP_DMA_AWLEN		GENMASK(3, 0)
+#define ZYNQMP_DMA_AWLEN_OFST		0
+
+/* Descriptor Attribute register bit field definitions */
+#define ZYNQMP_DMA_AXCOHRNT		BIT(8)
+#define ZYNQMP_DMA_AXCACHE		GENMASK(7, 4)
+#define ZYNQMP_DMA_AXCACHE_OFST		4
+#define ZYNQMP_DMA_AXQOS		GENMASK(3, 0)
+#define ZYNQMP_DMA_AXQOS_OFST		0
+
+/* Control register 2 bit field definitions */
+#define ZYNQMP_DMA_ENABLE		BIT(0)
+
+/* Buffer Descriptor definitions */
+#define ZYNQMP_DMA_DESC_CTRL_STOP	0x10
+#define ZYNQMP_DMA_DESC_CTRL_COMP_INT	0x4
+#define ZYNQMP_DMA_DESC_CTRL_SIZE_256	0x2
+#define ZYNQMP_DMA_DESC_CTRL_COHRNT	0x1
+
+/* Interrupt Mask specific definitions */
+#define ZYNQMP_DMA_INT_ERR	(ZYNQMP_DMA_AXI_RD_DATA | \
+				ZYNQMP_DMA_AXI_WR_DATA | \
+				ZYNQMP_DMA_AXI_RD_DST_DSCR | \
+				ZYNQMP_DMA_AXI_RD_SRC_DSCR | \
+				ZYNQMP_DMA_INV_APB)
+#define ZYNQMP_DMA_INT_OVRFL	(ZYNQMP_DMA_BYTE_CNT_OVRFL | \
+				ZYNQMP_DMA_IRQ_SRC_ACCT_ERR | \
+				ZYNQMP_DMA_IRQ_DST_ACCT_ERR)
+#define ZYNQMP_DMA_INT_DONE	(ZYNQMP_DMA_DONE | ZYNQMP_DMA_DST_DSCR_DONE)
+#define ZYNQMP_DMA_INT_EN_DEFAULT_MASK	(ZYNQMP_DMA_INT_DONE | \
+					ZYNQMP_DMA_INT_ERR | \
+					ZYNQMP_DMA_INT_OVRFL | \
+					ZYNQMP_DMA_DST_DSCR_DONE)
+
+/* Max number of descriptors per channel */
+#define ZYNQMP_DMA_NUM_DESCS	32
+
+/* Max transfer size per descriptor */
+#define ZYNQMP_DMA_MAX_TRANS_LEN	0x40000000
+
+/* Reset values for data attributes */
+#define ZYNQMP_DMA_AXCACHE_VAL		0xF
+#define ZYNQMP_DMA_ARLEN_RST_VAL	0xF
+#define ZYNQMP_DMA_AWLEN_RST_VAL	0xF
+
+#define ZYNQMP_DMA_SRC_ISSUE_RST_VAL	0x1F
+
+#define ZYNQMP_DMA_IDS_DEFAULT_MASK	0xFFF
+
+/* Bus width in bits */
+#define ZYNQMP_DMA_BUS_WIDTH_64		64
+#define ZYNQMP_DMA_BUS_WIDTH_128	128
+
+#define ZYNQMP_DMA_DESC_SIZE(chan)	(chan->desc_size)
+
+#define to_chan(chan)		container_of(chan, struct zynqmp_dma_chan, \
+					     common)
+#define tx_to_desc(tx)		container_of(tx, struct zynqmp_dma_desc_sw, \
+					     async_tx)
+
+/**
+ * struct zynqmp_dma_desc_ll - Hw linked list descriptor
+ * @addr: Buffer address
+ * @size: Size of the buffer
+ * @ctrl: Control word
+ * @nxtdscraddr: Next descriptor base address
+ * @rsvd: Reserved field and for Hw internal use.
+ */
+struct zynqmp_dma_desc_ll {
+	u64 addr;
+	u32 size;
+	u32 ctrl;
+	u64 nxtdscraddr;
+	u64 rsvd;
+}; __aligned(64)
+
+/**
+ * struct zynqmp_dma_desc_sw - Per Transaction structure
+ * @src: Source address for simple mode dma
+ * @dst: Destination address for simple mode dma
+ * @len: Transfer length for simple mode dma
+ * @node: Node in the channel descriptor list
+ * @tx_list: List head for the current transfer
+ * @async_tx: Async transaction descriptor
+ * @src_v: Virtual address of the src descriptor
+ * @src_p: Physical address of the src descriptor
+ * @dst_v: Virtual address of the dst descriptor
+ * @dst_p: Physical address of the dst descriptor
+ */
+struct zynqmp_dma_desc_sw {
+	u64 src;
+	u64 dst;
+	u32 len;
+	struct list_head node;
+	struct list_head tx_list;
+	struct dma_async_tx_descriptor async_tx;
+	struct zynqmp_dma_desc_ll *src_v;
+	dma_addr_t src_p;
+	struct zynqmp_dma_desc_ll *dst_v;
+	dma_addr_t dst_p;
+};
+
+/**
+ * struct zynqmp_dma_chan - Driver specific DMA channel structure
+ * @zdev: Driver specific device structure
+ * @regs: Control registers offset
+ * @lock: Descriptor operation lock
+ * @pending_list: Descriptors waiting
+ * @free_list: Descriptors free
+ * @active_list: Descriptors active
+ * @sw_desc_pool: SW descriptor pool
+ * @done_list: Complete descriptors
+ * @common: DMA common channel
+ * @desc_pool_v: Statically allocated descriptor base
+ * @desc_pool_p: Physical allocated descriptor base
+ * @desc_free_cnt: Descriptor available count
+ * @dev: The dma device
+ * @irq: Channel IRQ
+ * @is_dmacoherent: Tells whether dma operations are coherent or not
+ * @tasklet: Cleanup work after irq
+ * @idle : Channel status;
+ * @desc_size: Size of the low level descriptor
+ * @err: Channel has errors
+ * @bus_width: Bus width
+ * @src_burst_len: Source burst length
+ * @dst_burst_len: Dest burst length
+ * @clk_main: Pointer to main clock
+ * @clk_apb: Pointer to apb clock
+ */
+struct zynqmp_dma_chan {
+	struct zynqmp_dma_device *zdev;
+	void __iomem *regs;
+	spinlock_t lock;
+	struct list_head pending_list;
+	struct list_head free_list;
+	struct list_head active_list;
+	struct zynqmp_dma_desc_sw *sw_desc_pool;
+	struct list_head done_list;
+	struct dma_chan common;
+	void *desc_pool_v;
+	dma_addr_t desc_pool_p;
+	u32 desc_free_cnt;
+	struct device *dev;
+	int irq;
+	bool is_dmacoherent;
+	struct tasklet_struct tasklet;
+	bool idle;
+	u32 desc_size;
+	bool err;
+	u32 bus_width;
+	u32 src_burst_len;
+	u32 dst_burst_len;
+	struct clk *clk_main;
+	struct clk *clk_apb;
+};
+
+/**
+ * struct zynqmp_dma_device - DMA device structure
+ * @dev: Device Structure
+ * @common: DMA device structure
+ * @chan: Driver specific DMA channel
+ */
+struct zynqmp_dma_device {
+	struct device *dev;
+	struct dma_device common;
+	struct zynqmp_dma_chan *chan;
+};
+
+static inline void zynqmp_dma_writeq(struct zynqmp_dma_chan *chan, u32 reg,
+				     u64 value)
+{
+	lo_hi_writeq(value, chan->regs + reg);
+}
+
+/**
+ * zynqmp_dma_update_desc_to_ctrlr - Updates descriptor to the controller
+ * @chan: ZynqMP DMA DMA channel pointer
+ * @desc: Transaction descriptor pointer
+ */
+static void zynqmp_dma_update_desc_to_ctrlr(struct zynqmp_dma_chan *chan,
+				      struct zynqmp_dma_desc_sw *desc)
+{
+	dma_addr_t addr;
+
+	addr = desc->src_p;
+	zynqmp_dma_writeq(chan, ZYNQMP_DMA_SRC_START_LSB, addr);
+	addr = desc->dst_p;
+	zynqmp_dma_writeq(chan, ZYNQMP_DMA_DST_START_LSB, addr);
+}
+
+/**
+ * zynqmp_dma_desc_config_eod - Mark the descriptor as end descriptor
+ * @chan: ZynqMP DMA channel pointer
+ * @desc: Hw descriptor pointer
+ */
+static void zynqmp_dma_desc_config_eod(struct zynqmp_dma_chan *chan,
+				       void *desc)
+{
+	struct zynqmp_dma_desc_ll *hw = (struct zynqmp_dma_desc_ll *)desc;
+
+	hw->ctrl |= ZYNQMP_DMA_DESC_CTRL_STOP;
+	hw++;
+	hw->ctrl |= ZYNQMP_DMA_DESC_CTRL_COMP_INT | ZYNQMP_DMA_DESC_CTRL_STOP;
+}
+
+/**
+ * zynqmp_dma_config_sg_ll_desc - Configure the linked list descriptor
+ * @chan: ZynqMP DMA channel pointer
+ * @sdesc: Hw descriptor pointer
+ * @src: Source buffer address
+ * @dst: Destination buffer address
+ * @len: Transfer length
+ * @prev: Previous hw descriptor pointer
+ */
+static void zynqmp_dma_config_sg_ll_desc(struct zynqmp_dma_chan *chan,
+				   struct zynqmp_dma_desc_ll *sdesc,
+				   dma_addr_t src, dma_addr_t dst, size_t len,
+				   struct zynqmp_dma_desc_ll *prev)
+{
+	struct zynqmp_dma_desc_ll *ddesc = sdesc + 1;
+
+	sdesc->size = ddesc->size = len;
+	sdesc->addr = src;
+	ddesc->addr = dst;
+
+	sdesc->ctrl = ddesc->ctrl = ZYNQMP_DMA_DESC_CTRL_SIZE_256;
+	if (chan->is_dmacoherent) {
+		sdesc->ctrl |= ZYNQMP_DMA_DESC_CTRL_COHRNT;
+		ddesc->ctrl |= ZYNQMP_DMA_DESC_CTRL_COHRNT;
+	}
+
+	if (prev) {
+		dma_addr_t addr = chan->desc_pool_p +
+			    ((dma_addr_t)sdesc - (dma_addr_t)chan->desc_pool_v);
+		ddesc = prev + 1;
+		prev->nxtdscraddr = addr;
+		ddesc->nxtdscraddr = addr + ZYNQMP_DMA_DESC_SIZE(chan);
+	}
+}
+
+/**
+ * zynqmp_dma_init - Initialize the channel
+ * @chan: ZynqMP DMA channel pointer
+ */
+static void zynqmp_dma_init(struct zynqmp_dma_chan *chan)
+{
+	u32 val;
+
+	writel(ZYNQMP_DMA_IDS_DEFAULT_MASK, chan->regs + ZYNQMP_DMA_IDS);
+	val = readl(chan->regs + ZYNQMP_DMA_ISR);
+	writel(val, chan->regs + ZYNQMP_DMA_ISR);
+
+	if (chan->is_dmacoherent) {
+		val = ZYNQMP_DMA_AXCOHRNT;
+		val = (val & ~ZYNQMP_DMA_AXCACHE) |
+			(ZYNQMP_DMA_AXCACHE_VAL << ZYNQMP_DMA_AXCACHE_OFST);
+		writel(val, chan->regs + ZYNQMP_DMA_DSCR_ATTR);
+	}
+
+	val = readl(chan->regs + ZYNQMP_DMA_DATA_ATTR);
+	if (chan->is_dmacoherent) {
+		val = (val & ~ZYNQMP_DMA_ARCACHE) |
+			(ZYNQMP_DMA_AXCACHE_VAL << ZYNQMP_DMA_ARCACHE_OFST);
+		val = (val & ~ZYNQMP_DMA_AWCACHE) |
+			(ZYNQMP_DMA_AXCACHE_VAL << ZYNQMP_DMA_AWCACHE_OFST);
+	}
+	writel(val, chan->regs + ZYNQMP_DMA_DATA_ATTR);
+
+	/* Clearing the interrupt account rgisters */
+	val = readl(chan->regs + ZYNQMP_DMA_IRQ_SRC_ACCT);
+	val = readl(chan->regs + ZYNQMP_DMA_IRQ_DST_ACCT);
+
+	chan->idle = true;
+}
+
+/**
+ * zynqmp_dma_tx_submit - Submit DMA transaction
+ * @tx: Async transaction descriptor pointer
+ *
+ * Return: cookie value
+ */
+static dma_cookie_t zynqmp_dma_tx_submit(struct dma_async_tx_descriptor *tx)
+{
+	struct zynqmp_dma_chan *chan = to_chan(tx->chan);
+	struct zynqmp_dma_desc_sw *desc, *new;
+	dma_cookie_t cookie;
+
+	new = tx_to_desc(tx);
+	spin_lock_bh(&chan->lock);
+	cookie = dma_cookie_assign(tx);
+
+	if (!list_empty(&chan->pending_list)) {
+		desc = list_last_entry(&chan->pending_list,
+				     struct zynqmp_dma_desc_sw, node);
+		if (!list_empty(&desc->tx_list))
+			desc = list_last_entry(&desc->tx_list,
+					       struct zynqmp_dma_desc_sw, node);
+		desc->src_v->nxtdscraddr = new->src_p;
+		desc->src_v->ctrl &= ~ZYNQMP_DMA_DESC_CTRL_STOP;
+		desc->dst_v->nxtdscraddr = new->dst_p;
+		desc->dst_v->ctrl &= ~ZYNQMP_DMA_DESC_CTRL_STOP;
+	}
+
+	list_add_tail(&new->node, &chan->pending_list);
+	spin_unlock_bh(&chan->lock);
+
+	return cookie;
+}
+
+/**
+ * zynqmp_dma_get_descriptor - Get the sw descriptor from the pool
+ * @chan: ZynqMP DMA channel pointer
+ *
+ * Return: The sw descriptor
+ */
+static struct zynqmp_dma_desc_sw *
+zynqmp_dma_get_descriptor(struct zynqmp_dma_chan *chan)
+{
+	struct zynqmp_dma_desc_sw *desc;
+
+	spin_lock_bh(&chan->lock);
+	desc = list_first_entry(&chan->free_list,
+				struct zynqmp_dma_desc_sw, node);
+	list_del(&desc->node);
+	spin_unlock_bh(&chan->lock);
+
+	INIT_LIST_HEAD(&desc->tx_list);
+	/* Clear the src and dst descriptor memory */
+	memset((void *)desc->src_v, 0, ZYNQMP_DMA_DESC_SIZE(chan));
+	memset((void *)desc->dst_v, 0, ZYNQMP_DMA_DESC_SIZE(chan));
+
+	return desc;
+}
+
+/**
+ * zynqmp_dma_free_descriptor - Issue pending transactions
+ * @chan: ZynqMP DMA channel pointer
+ * @sdesc: Transaction descriptor pointer
+ */
+static void zynqmp_dma_free_descriptor(struct zynqmp_dma_chan *chan,
+				 struct zynqmp_dma_desc_sw *sdesc)
+{
+	struct zynqmp_dma_desc_sw *child, *next;
+
+	chan->desc_free_cnt++;
+	list_add_tail(&sdesc->node, &chan->free_list);
+	list_for_each_entry_safe(child, next, &sdesc->tx_list, node) {
+		chan->desc_free_cnt++;
+		list_move_tail(&child->node, &chan->free_list);
+	}
+}
+
+/**
+ * zynqmp_dma_free_desc_list - Free descriptors list
+ * @chan: ZynqMP DMA channel pointer
+ * @list: List to parse and delete the descriptor
+ */
+static void zynqmp_dma_free_desc_list(struct zynqmp_dma_chan *chan,
+				      struct list_head *list)
+{
+	struct zynqmp_dma_desc_sw *desc, *next;
+
+	list_for_each_entry_safe(desc, next, list, node)
+		zynqmp_dma_free_descriptor(chan, desc);
+}
+
+/**
+ * zynqmp_dma_alloc_chan_resources - Allocate channel resources
+ * @dchan: DMA channel
+ *
+ * Return: Number of descriptors on success and failure value on error
+ */
+static int zynqmp_dma_alloc_chan_resources(struct dma_chan *dchan)
+{
+	struct zynqmp_dma_chan *chan = to_chan(dchan);
+	struct zynqmp_dma_desc_sw *desc;
+	int i;
+
+	chan->sw_desc_pool = kzalloc(sizeof(*desc) * ZYNQMP_DMA_NUM_DESCS,
+				     GFP_KERNEL);
+	if (!chan->sw_desc_pool)
+		return -ENOMEM;
+
+	chan->idle = true;
+	chan->desc_free_cnt = ZYNQMP_DMA_NUM_DESCS;
+
+	INIT_LIST_HEAD(&chan->free_list);
+
+	for (i = 0; i < ZYNQMP_DMA_NUM_DESCS; i++) {
+		desc = chan->sw_desc_pool + i;
+		dma_async_tx_descriptor_init(&desc->async_tx, &chan->common);
+		desc->async_tx.tx_submit = zynqmp_dma_tx_submit;
+		list_add_tail(&desc->node, &chan->free_list);
+	}
+
+	chan->desc_pool_v = dma_zalloc_coherent(chan->dev,
+				(2 * chan->desc_size * ZYNQMP_DMA_NUM_DESCS),
+				&chan->desc_pool_p, GFP_KERNEL);
+	if (!chan->desc_pool_v)
+		return -ENOMEM;
+
+	for (i = 0; i < ZYNQMP_DMA_NUM_DESCS; i++) {
+		desc = chan->sw_desc_pool + i;
+		desc->src_v = (struct zynqmp_dma_desc_ll *) (chan->desc_pool_v +
+					(i * ZYNQMP_DMA_DESC_SIZE(chan) * 2));
+		desc->dst_v = (struct zynqmp_dma_desc_ll *) (desc->src_v + 1);
+		desc->src_p = chan->desc_pool_p +
+				(i * ZYNQMP_DMA_DESC_SIZE(chan) * 2);
+		desc->dst_p = desc->src_p + ZYNQMP_DMA_DESC_SIZE(chan);
+	}
+
+	return ZYNQMP_DMA_NUM_DESCS;
+}
+
+/**
+ * zynqmp_dma_start - Start DMA channel
+ * @chan: ZynqMP DMA channel pointer
+ */
+static void zynqmp_dma_start(struct zynqmp_dma_chan *chan)
+{
+	writel(ZYNQMP_DMA_INT_EN_DEFAULT_MASK, chan->regs + ZYNQMP_DMA_IER);
+	chan->idle = false;
+	writel(ZYNQMP_DMA_ENABLE, chan->regs + ZYNQMP_DMA_CTRL2);
+}
+
+/**
+ * zynqmp_dma_handle_ovfl_int - Process the overflow interrupt
+ * @chan: ZynqMP DMA channel pointer
+ * @status: Interrupt status value
+ */
+static void zynqmp_dma_handle_ovfl_int(struct zynqmp_dma_chan *chan, u32 status)
+{
+	u32 val;
+
+	if (status & ZYNQMP_DMA_IRQ_DST_ACCT_ERR)
+		val = readl(chan->regs + ZYNQMP_DMA_IRQ_DST_ACCT);
+	if (status & ZYNQMP_DMA_IRQ_SRC_ACCT_ERR)
+		val = readl(chan->regs + ZYNQMP_DMA_IRQ_SRC_ACCT);
+}
+
+static void zynqmp_dma_config(struct zynqmp_dma_chan *chan)
+{
+	u32 val;
+
+	val = readl(chan->regs + ZYNQMP_DMA_CTRL0);
+	val |= ZYNQMP_DMA_POINT_TYPE_SG;
+	writel(val, chan->regs + ZYNQMP_DMA_CTRL0);
+
+	val = readl(chan->regs + ZYNQMP_DMA_DATA_ATTR);
+	val = (val & ~ZYNQMP_DMA_ARLEN) |
+		(chan->src_burst_len << ZYNQMP_DMA_ARLEN_OFST);
+	val = (val & ~ZYNQMP_DMA_AWLEN) |
+		(chan->dst_burst_len << ZYNQMP_DMA_AWLEN_OFST);
+	writel(val, chan->regs + ZYNQMP_DMA_DATA_ATTR);
+}
+
+/**
+ * zynqmp_dma_device_config - Zynqmp dma device configuration
+ * @dchan: DMA channel
+ * @config: DMA device config
+ */
+static int zynqmp_dma_device_config(struct dma_chan *dchan,
+				    struct dma_slave_config *config)
+{
+	struct zynqmp_dma_chan *chan = to_chan(dchan);
+
+	chan->src_burst_len = config->src_maxburst;
+	chan->dst_burst_len = config->dst_maxburst;
+
+	return 0;
+}
+
+/**
+ * zynqmp_dma_start_transfer - Initiate the new transfer
+ * @chan: ZynqMP DMA channel pointer
+ */
+static void zynqmp_dma_start_transfer(struct zynqmp_dma_chan *chan)
+{
+	struct zynqmp_dma_desc_sw *desc;
+
+	if (!chan->idle)
+		return;
+
+	zynqmp_dma_config(chan);
+
+	desc = list_first_entry_or_null(&chan->pending_list,
+					struct zynqmp_dma_desc_sw, node);
+	if (!desc)
+		return;
+
+	list_splice_tail_init(&chan->pending_list, &chan->active_list);
+	zynqmp_dma_update_desc_to_ctrlr(chan, desc);
+	zynqmp_dma_start(chan);
+}
+
+
+/**
+ * zynqmp_dma_chan_desc_cleanup - Cleanup the completed descriptors
+ * @chan: ZynqMP DMA channel
+ */
+static void zynqmp_dma_chan_desc_cleanup(struct zynqmp_dma_chan *chan)
+{
+	struct zynqmp_dma_desc_sw *desc, *next;
+
+	list_for_each_entry_safe(desc, next, &chan->done_list, node) {
+		dma_async_tx_callback callback;
+		void *callback_param;
+
+		list_del(&desc->node);
+
+		callback = desc->async_tx.callback;
+		callback_param = desc->async_tx.callback_param;
+		if (callback) {
+			spin_unlock(&chan->lock);
+			callback(callback_param);
+			spin_lock(&chan->lock);
+		}
+
+		/* Run any dependencies, then free the descriptor */
+		zynqmp_dma_free_descriptor(chan, desc);
+	}
+}
+
+/**
+ * zynqmp_dma_complete_descriptor - Mark the active descriptor as complete
+ * @chan: ZynqMP DMA channel pointer
+ */
+static void zynqmp_dma_complete_descriptor(struct zynqmp_dma_chan *chan)
+{
+	struct zynqmp_dma_desc_sw *desc;
+
+	desc = list_first_entry_or_null(&chan->active_list,
+					struct zynqmp_dma_desc_sw, node);
+	if (!desc)
+		return;
+	list_del(&desc->node);
+	dma_cookie_complete(&desc->async_tx);
+	list_add_tail(&desc->node, &chan->done_list);
+}
+
+/**
+ * zynqmp_dma_issue_pending - Issue pending transactions
+ * @dchan: DMA channel pointer
+ */
+static void zynqmp_dma_issue_pending(struct dma_chan *dchan)
+{
+	struct zynqmp_dma_chan *chan = to_chan(dchan);
+
+	spin_lock_bh(&chan->lock);
+	zynqmp_dma_start_transfer(chan);
+	spin_unlock_bh(&chan->lock);
+}
+
+/**
+ * zynqmp_dma_free_descriptors - Free channel descriptors
+ * @dchan: DMA channel pointer
+ */
+static void zynqmp_dma_free_descriptors(struct zynqmp_dma_chan *chan)
+{
+	zynqmp_dma_free_desc_list(chan, &chan->active_list);
+	zynqmp_dma_free_desc_list(chan, &chan->pending_list);
+	zynqmp_dma_free_desc_list(chan, &chan->done_list);
+}
+
+/**
+ * zynqmp_dma_free_chan_resources - Free channel resources
+ * @dchan: DMA channel pointer
+ */
+static void zynqmp_dma_free_chan_resources(struct dma_chan *dchan)
+{
+	struct zynqmp_dma_chan *chan = to_chan(dchan);
+
+	spin_lock_bh(&chan->lock);
+	zynqmp_dma_free_descriptors(chan);
+	spin_unlock_bh(&chan->lock);
+	dma_free_coherent(chan->dev,
+		(2 * ZYNQMP_DMA_DESC_SIZE(chan) * ZYNQMP_DMA_NUM_DESCS),
+		chan->desc_pool_v, chan->desc_pool_p);
+	kfree(chan->sw_desc_pool);
+}
+
+/**
+ * zynqmp_dma_reset - Reset the channel
+ * @chan: ZynqMP DMA channel pointer
+ */
+static void zynqmp_dma_reset(struct zynqmp_dma_chan *chan)
+{
+	writel(ZYNQMP_DMA_IDS_DEFAULT_MASK, chan->regs + ZYNQMP_DMA_IDS);
+
+	zynqmp_dma_complete_descriptor(chan);
+	zynqmp_dma_chan_desc_cleanup(chan);
+	zynqmp_dma_free_descriptors(chan);
+	zynqmp_dma_init(chan);
+}
+
+/**
+ * zynqmp_dma_irq_handler - ZynqMP DMA Interrupt handler
+ * @irq: IRQ number
+ * @data: Pointer to the ZynqMP DMA channel structure
+ *
+ * Return: IRQ_HANDLED/IRQ_NONE
+ */
+static irqreturn_t zynqmp_dma_irq_handler(int irq, void *data)
+{
+	struct zynqmp_dma_chan *chan = (struct zynqmp_dma_chan *)data;
+	u32 isr, imr, status;
+	irqreturn_t ret = IRQ_NONE;
+
+	isr = readl(chan->regs + ZYNQMP_DMA_ISR);
+	imr = readl(chan->regs + ZYNQMP_DMA_IMR);
+	status = isr & ~imr;
+
+	writel(isr, chan->regs + ZYNQMP_DMA_ISR);
+	if (status & ZYNQMP_DMA_INT_DONE) {
+		tasklet_schedule(&chan->tasklet);
+		ret = IRQ_HANDLED;
+	}
+
+	if (status & ZYNQMP_DMA_DONE)
+		chan->idle = true;
+
+	if (status & ZYNQMP_DMA_INT_ERR) {
+		chan->err = true;
+		tasklet_schedule(&chan->tasklet);
+		dev_err(chan->dev, "Channel %p has errors\n", chan);
+		ret = IRQ_HANDLED;
+	}
+
+	if (status & ZYNQMP_DMA_INT_OVRFL) {
+		zynqmp_dma_handle_ovfl_int(chan, status);
+		dev_info(chan->dev, "Channel %p overflow interrupt\n", chan);
+		ret = IRQ_HANDLED;
+	}
+
+	return ret;
+}
+
+/**
+ * zynqmp_dma_do_tasklet - Schedule completion tasklet
+ * @data: Pointer to the ZynqMP DMA channel structure
+ */
+static void zynqmp_dma_do_tasklet(unsigned long data)
+{
+	struct zynqmp_dma_chan *chan = (struct zynqmp_dma_chan *)data;
+	u32 count;
+
+	spin_lock(&chan->lock);
+
+	if (chan->err) {
+		zynqmp_dma_reset(chan);
+		chan->err = false;
+		goto unlock;
+	}
+
+	count = readl(chan->regs + ZYNQMP_DMA_IRQ_DST_ACCT);
+
+	while (count) {
+		zynqmp_dma_complete_descriptor(chan);
+		zynqmp_dma_chan_desc_cleanup(chan);
+		count--;
+	}
+
+	if (chan->idle)
+		zynqmp_dma_start_transfer(chan);
+
+unlock:
+	spin_unlock(&chan->lock);
+}
+
+/**
+ * zynqmp_dma_device_terminate_all - Aborts all transfers on a channel
+ * @dchan: DMA channel pointer
+ *
+ * Return: Always '0'
+ */
+static int zynqmp_dma_device_terminate_all(struct dma_chan *dchan)
+{
+	struct zynqmp_dma_chan *chan = to_chan(dchan);
+
+	spin_lock_bh(&chan->lock);
+	writel(ZYNQMP_DMA_IDS_DEFAULT_MASK, chan->regs + ZYNQMP_DMA_IDS);
+	zynqmp_dma_free_descriptors(chan);
+	spin_unlock_bh(&chan->lock);
+
+	return 0;
+}
+
+/**
+ * zynqmp_dma_prep_memcpy - prepare descriptors for memcpy transaction
+ * @dchan: DMA channel
+ * @dma_dst: Destination buffer address
+ * @dma_src: Source buffer address
+ * @len: Transfer length
+ * @flags: transfer ack flags
+ *
+ * Return: Async transaction descriptor on success and NULL on failure
+ */
+static struct dma_async_tx_descriptor *zynqmp_dma_prep_memcpy(
+				struct dma_chan *dchan, dma_addr_t dma_dst,
+				dma_addr_t dma_src, size_t len, ulong flags)
+{
+	struct zynqmp_dma_chan *chan;
+	struct zynqmp_dma_desc_sw *new, *first = NULL;
+	void *desc = NULL, *prev = NULL;
+	size_t copy;
+	u32 desc_cnt;
+
+	chan = to_chan(dchan);
+
+	if (len > ZYNQMP_DMA_MAX_TRANS_LEN)
+		return NULL;
+
+	desc_cnt = DIV_ROUND_UP(len, ZYNQMP_DMA_MAX_TRANS_LEN);
+
+	spin_lock_bh(&chan->lock);
+	if (desc_cnt > chan->desc_free_cnt) {
+		spin_unlock_bh(&chan->lock);
+		dev_dbg(chan->dev, "chan %p descs are not available\n", chan);
+		return NULL;
+	}
+	chan->desc_free_cnt = chan->desc_free_cnt - desc_cnt;
+	spin_unlock_bh(&chan->lock);
+
+	do {
+		/* Allocate and populate the descriptor */
+		new = zynqmp_dma_get_descriptor(chan);
+
+		copy = min_t(size_t, len, ZYNQMP_DMA_MAX_TRANS_LEN);
+		desc = (struct zynqmp_dma_desc_ll *)new->src_v;
+		zynqmp_dma_config_sg_ll_desc(chan, desc, dma_src,
+					     dma_dst, copy, prev);
+		prev = desc;
+		len -= copy;
+		dma_src += copy;
+		dma_dst += copy;
+		if (!first)
+			first = new;
+		else
+			list_add_tail(&new->node, &first->tx_list);
+	} while (len);
+
+	zynqmp_dma_desc_config_eod(chan, desc);
+	async_tx_ack(&first->async_tx);
+	first->async_tx.flags = flags;
+	return &first->async_tx;
+}
+
+/**
+ * zynqmp_dma_prep_slave_sg - prepare descriptors for a memory sg transaction
+ * @dchan: DMA channel
+ * @dst_sg: Destination scatter list
+ * @dst_sg_len: Number of entries in destination scatter list
+ * @src_sg: Source scatter list
+ * @src_sg_len: Number of entries in source scatter list
+ * @flags: transfer ack flags
+ *
+ * Return: Async transaction descriptor on success and NULL on failure
+ */
+static struct dma_async_tx_descriptor *zynqmp_dma_prep_sg(
+			struct dma_chan *dchan, struct scatterlist *dst_sg,
+			unsigned int dst_sg_len, struct scatterlist *src_sg,
+			unsigned int src_sg_len, unsigned long flags)
+{
+	struct zynqmp_dma_desc_sw *new, *first = NULL;
+	struct zynqmp_dma_chan *chan = to_chan(dchan);
+	void *desc = NULL, *prev = NULL;
+	size_t len, dst_avail, src_avail;
+	dma_addr_t dma_dst, dma_src;
+	u32 desc_cnt = 0, i;
+	struct scatterlist *sg;
+
+	for_each_sg(src_sg, sg, src_sg_len, i)
+		desc_cnt += DIV_ROUND_UP(sg_dma_len(sg),
+					 ZYNQMP_DMA_MAX_TRANS_LEN);
+
+	spin_lock_bh(&chan->lock);
+	if (desc_cnt > chan->desc_free_cnt) {
+		spin_unlock_bh(&chan->lock);
+		dev_dbg(chan->dev, "chan %p descs are not available\n", chan);
+		return NULL;
+	}
+	chan->desc_free_cnt = chan->desc_free_cnt - desc_cnt;
+	spin_unlock_bh(&chan->lock);
+
+	dst_avail = sg_dma_len(dst_sg);
+	src_avail = sg_dma_len(src_sg);
+
+	/* Run until we are out of scatterlist entries */
+	while (true) {
+		/* Allocate and populate the descriptor */
+		new = zynqmp_dma_get_descriptor(chan);
+		desc = (struct zynqmp_dma_desc_ll *)new->src_v;
+		len = min_t(size_t, src_avail, dst_avail);
+		len = min_t(size_t, len, ZYNQMP_DMA_MAX_TRANS_LEN);
+		if (len == 0)
+			goto fetch;
+		dma_dst = sg_dma_address(dst_sg) + sg_dma_len(dst_sg) -
+			dst_avail;
+		dma_src = sg_dma_address(src_sg) + sg_dma_len(src_sg) -
+			src_avail;
+
+		zynqmp_dma_config_sg_ll_desc(chan, desc, dma_src, dma_dst,
+					     len, prev);
+		prev = desc;
+		dst_avail -= len;
+		src_avail -= len;
+
+		if (!first)
+			first = new;
+		else
+			list_add_tail(&new->node, &first->tx_list);
+fetch:
+		/* Fetch the next dst scatterlist entry */
+		if (dst_avail == 0) {
+			if (dst_sg_len == 0)
+				break;
+			dst_sg = sg_next(dst_sg);
+			if (dst_sg == NULL)
+				break;
+			dst_sg_len--;
+			dst_avail = sg_dma_len(dst_sg);
+		}
+		/* Fetch the next src scatterlist entry */
+		if (src_avail == 0) {
+			if (src_sg_len == 0)
+				break;
+			src_sg = sg_next(src_sg);
+			if (src_sg == NULL)
+				break;
+			src_sg_len--;
+			src_avail = sg_dma_len(src_sg);
+		}
+	}
+
+	zynqmp_dma_desc_config_eod(chan, desc);
+	first->async_tx.flags = flags;
+	return &first->async_tx;
+}
+
+/**
+ * zynqmp_dma_chan_remove - Channel remove function
+ * @chan: ZynqMP DMA channel pointer
+ */
+static void zynqmp_dma_chan_remove(struct zynqmp_dma_chan *chan)
+{
+	if (!chan)
+		return;
+
+	devm_free_irq(chan->zdev->dev, chan->irq, chan);
+	tasklet_kill(&chan->tasklet);
+	list_del(&chan->common.device_node);
+	clk_disable_unprepare(chan->clk_apb);
+	clk_disable_unprepare(chan->clk_main);
+}
+
+/**
+ * zynqmp_dma_chan_probe - Per Channel Probing
+ * @zdev: Driver specific device structure
+ * @pdev: Pointer to the platform_device structure
+ *
+ * Return: '0' on success and failure value on error
+ */
+static int zynqmp_dma_chan_probe(struct zynqmp_dma_device *zdev,
+			   struct platform_device *pdev)
+{
+	struct zynqmp_dma_chan *chan;
+	struct resource *res;
+	struct device_node *node = pdev->dev.of_node;
+	int err;
+
+	chan = devm_kzalloc(zdev->dev, sizeof(*chan), GFP_KERNEL);
+	if (!chan)
+		return -ENOMEM;
+	chan->dev = zdev->dev;
+	chan->zdev = zdev;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	chan->regs = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(chan->regs))
+		return PTR_ERR(chan->regs);
+
+	chan->bus_width = ZYNQMP_DMA_BUS_WIDTH_64;
+	chan->dst_burst_len = ZYNQMP_DMA_AWLEN_RST_VAL;
+	chan->src_burst_len = ZYNQMP_DMA_ARLEN_RST_VAL;
+	err = of_property_read_u32(node, "xlnx,bus-width", &chan->bus_width);
+	if ((err < 0) && ((chan->bus_width != ZYNQMP_DMA_BUS_WIDTH_64) ||
+			  (chan->bus_width != ZYNQMP_DMA_BUS_WIDTH_128))) {
+		dev_err(zdev->dev, "invalid bus-width value");
+		return err;
+	}
+
+	chan->is_dmacoherent =  of_property_read_bool(node, "dma-coherent");
+	zdev->chan = chan;
+	tasklet_init(&chan->tasklet, zynqmp_dma_do_tasklet, (ulong)chan);
+	spin_lock_init(&chan->lock);
+	INIT_LIST_HEAD(&chan->active_list);
+	INIT_LIST_HEAD(&chan->pending_list);
+	INIT_LIST_HEAD(&chan->done_list);
+	INIT_LIST_HEAD(&chan->free_list);
+
+	dma_cookie_init(&chan->common);
+	chan->common.device = &zdev->common;
+	list_add_tail(&chan->common.device_node, &zdev->common.channels);
+
+	zynqmp_dma_init(chan);
+	chan->irq = platform_get_irq(pdev, 0);
+	if (chan->irq < 0)
+		return -ENXIO;
+	err = devm_request_irq(&pdev->dev, chan->irq, zynqmp_dma_irq_handler, 0,
+			       "zynqmp-dma", chan);
+	if (err)
+		return err;
+	chan->clk_main = devm_clk_get(&pdev->dev, "clk_main");
+	if (IS_ERR(chan->clk_main)) {
+		dev_err(&pdev->dev, "main clock not found.\n");
+		return PTR_ERR(chan->clk_main);
+	}
+
+	chan->clk_apb = devm_clk_get(&pdev->dev, "clk_apb");
+	if (IS_ERR(chan->clk_apb)) {
+		dev_err(&pdev->dev, "apb clock not found.\n");
+		return PTR_ERR(chan->clk_apb);
+	}
+
+	err = clk_prepare_enable(chan->clk_main);
+	if (err) {
+		dev_err(&pdev->dev, "Unable to enable main clock.\n");
+		return err;
+	}
+
+	err = clk_prepare_enable(chan->clk_apb);
+	if (err) {
+		clk_disable_unprepare(chan->clk_main);
+		dev_err(&pdev->dev, "Unable to enable apb clock.\n");
+		return err;
+	}
+
+	chan->desc_size = sizeof(struct zynqmp_dma_desc_ll);
+	chan->idle = true;
+	return 0;
+}
+
+/**
+ * of_zynqmp_dma_xlate - Translation function
+ * @dma_spec: Pointer to DMA specifier as found in the device tree
+ * @ofdma: Pointer to DMA controller data
+ *
+ * Return: DMA channel pointer on success and NULL on error
+ */
+static struct dma_chan *of_zynqmp_dma_xlate(struct of_phandle_args *dma_spec,
+					    struct of_dma *ofdma)
+{
+	struct zynqmp_dma_device *zdev = ofdma->of_dma_data;
+
+	return dma_get_slave_channel(&zdev->chan->common);
+}
+
+/**
+ * zynqmp_dma_probe - Driver probe function
+ * @pdev: Pointer to the platform_device structure
+ *
+ * Return: '0' on success and failure value on error
+ */
+static int zynqmp_dma_probe(struct platform_device *pdev)
+{
+	struct zynqmp_dma_device *zdev;
+	struct dma_device *p;
+	int ret;
+
+	zdev = devm_kzalloc(&pdev->dev, sizeof(*zdev), GFP_KERNEL);
+	if (!zdev)
+		return -ENOMEM;
+
+	zdev->dev = &pdev->dev;
+	INIT_LIST_HEAD(&zdev->common.channels);
+
+	dma_set_mask(&pdev->dev, DMA_BIT_MASK(44));
+	dma_cap_set(DMA_SG, zdev->common.cap_mask);
+	dma_cap_set(DMA_MEMCPY, zdev->common.cap_mask);
+
+	p = &zdev->common;
+	p->device_prep_dma_sg = zynqmp_dma_prep_sg;
+	p->device_prep_dma_memcpy = zynqmp_dma_prep_memcpy;
+	p->device_terminate_all = zynqmp_dma_device_terminate_all;
+	p->device_issue_pending = zynqmp_dma_issue_pending;
+	p->device_alloc_chan_resources = zynqmp_dma_alloc_chan_resources;
+	p->device_free_chan_resources = zynqmp_dma_free_chan_resources;
+	p->device_tx_status = dma_cookie_status;
+	p->device_config = zynqmp_dma_device_config;
+	p->dev = &pdev->dev;
+
+	platform_set_drvdata(pdev, zdev);
+
+	ret = zynqmp_dma_chan_probe(zdev, pdev);
+	if (ret) {
+		dev_err(&pdev->dev, "Probing channel failed\n");
+		goto free_chan_resources;
+	}
+
+	p->dst_addr_widths = BIT(zdev->chan->bus_width / 8);
+	p->src_addr_widths = BIT(zdev->chan->bus_width / 8);
+
+	dma_async_device_register(&zdev->common);
+
+	ret = of_dma_controller_register(pdev->dev.of_node,
+					 of_zynqmp_dma_xlate, zdev);
+	if (ret) {
+		dev_err(&pdev->dev, "Unable to register DMA to DT\n");
+		dma_async_device_unregister(&zdev->common);
+		goto free_chan_resources;
+	}
+
+	dev_info(&pdev->dev, "ZynqMP DMA driver Probe success\n");
+
+	return 0;
+
+free_chan_resources:
+	zynqmp_dma_chan_remove(zdev->chan);
+	return ret;
+}
+
+/**
+ * zynqmp_dma_remove - Driver remove function
+ * @pdev: Pointer to the platform_device structure
+ *
+ * Return: Always '0'
+ */
+static int zynqmp_dma_remove(struct platform_device *pdev)
+{
+	struct zynqmp_dma_device *zdev = platform_get_drvdata(pdev);
+
+	of_dma_controller_free(pdev->dev.of_node);
+	dma_async_device_unregister(&zdev->common);
+
+	zynqmp_dma_chan_remove(zdev->chan);
+
+	return 0;
+}
+
+static const struct of_device_id zynqmp_dma_of_match[] = {
+	{ .compatible = "xlnx,zynqmp-dma-1.0", },
+	{}
+};
+MODULE_DEVICE_TABLE(of, zynqmp_dma_of_match);
+
+static struct platform_driver zynqmp_dma_driver = {
+	.driver = {
+		.name = "xilinx-zynqmp-dma",
+		.of_match_table = zynqmp_dma_of_match,
+	},
+	.probe = zynqmp_dma_probe,
+	.remove = zynqmp_dma_remove,
+};
+
+module_platform_driver(zynqmp_dma_driver);
+
+MODULE_AUTHOR("Xilinx, Inc.");
+MODULE_DESCRIPTION("Xilinx ZynqMP DMA driver");