/*
 * DMA driver for Xilinx Video DMA Engine
 *
 * Copyright (C) 2010-2014 Xilinx, Inc. All rights reserved.
 *
 * Based on the Freescale DMA driver.
 *
 * Description:
 * The AXI Video Direct Memory Access (AXI VDMA) core is a soft Xilinx IP
 * core that provides high-bandwidth direct memory access between memory
 * and AXI4-Stream type video target peripherals. The core provides efficient
 * two dimensional DMA operations with independent asynchronous read (S2MM)
 * and write (MM2S) channel operation. It can be configured to have either
 * one channel or two channels. If configured as two channels, one is to
 * transmit to the video device (MM2S) and another is to receive from the
 * video device (S2MM). Initialization, status, interrupt and management
 * registers are accessed through an AXI4-Lite slave interface.
 *
 * The AXI Direct Memory Access (AXI DMA) core is a soft Xilinx IP core that
 * provides high-bandwidth one dimensional direct memory access between memory
 * and AXI4-Stream target peripherals. It supports one receive and one
 * transmit channel, both of them optional at synthesis time.
 *
 * The AXI CDMA, is a soft IP, which provides high-bandwidth Direct Memory
 * Access (DMA) between a memory-mapped source address and a memory-mapped
 * destination address.
 *
 * 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/iopoll.h>
#include <linux/module.h>
#include <linux/of_address.h>
#include <linux/of_dma.h>
#include <linux/of_platform.h>
#include <linux/of_irq.h>
#include <linux/slab.h>
#include <linux/clk.h>
#include <linux/io-64-nonatomic-lo-hi.h>

#include "../dmaengine.h"

/* Register/Descriptor Offsets */
#define XILINX_DMA_MM2S_CTRL_OFFSET             0x0000
#define XILINX_DMA_S2MM_CTRL_OFFSET             0x0030
#define XILINX_VDMA_MM2S_DESC_OFFSET            0x0050
#define XILINX_VDMA_S2MM_DESC_OFFSET            0x00a0

/* Control Registers */
#define XILINX_DMA_REG_DMACR                    0x0000
#define XILINX_DMA_DMACR_DELAY_MAX              0xff
#define XILINX_DMA_DMACR_DELAY_SHIFT            24
#define XILINX_DMA_DMACR_FRAME_COUNT_MAX        0xff
#define XILINX_DMA_DMACR_FRAME_COUNT_SHIFT      16
#define XILINX_DMA_DMACR_ERR_IRQ                BIT(14)
#define XILINX_DMA_DMACR_DLY_CNT_IRQ            BIT(13)
#define XILINX_DMA_DMACR_FRM_CNT_IRQ            BIT(12)
#define XILINX_DMA_DMACR_MASTER_SHIFT           8
#define XILINX_DMA_DMACR_FSYNCSRC_SHIFT 5
#define XILINX_DMA_DMACR_FRAMECNT_EN            BIT(4)
#define XILINX_DMA_DMACR_GENLOCK_EN             BIT(3)
#define XILINX_DMA_DMACR_RESET                  BIT(2)
#define XILINX_DMA_DMACR_CIRC_EN                BIT(1)
#define XILINX_DMA_DMACR_RUNSTOP                BIT(0)
#define XILINX_DMA_DMACR_FSYNCSRC_MASK          GENMASK(6, 5)
#define XILINX_DMA_DMACR_DELAY_MASK             GENMASK(31, 24)
#define XILINX_DMA_DMACR_FRAME_COUNT_MASK       GENMASK(23, 16)
#define XILINX_DMA_DMACR_MASTER_MASK            GENMASK(11, 8)

#define XILINX_DMA_REG_DMASR                    0x0004
#define XILINX_DMA_DMASR_EOL_LATE_ERR           BIT(15)
#define XILINX_DMA_DMASR_ERR_IRQ                BIT(14)
#define XILINX_DMA_DMASR_DLY_CNT_IRQ            BIT(13)
#define XILINX_DMA_DMASR_FRM_CNT_IRQ            BIT(12)
#define XILINX_DMA_DMASR_SOF_LATE_ERR           BIT(11)
#define XILINX_DMA_DMASR_SG_DEC_ERR             BIT(10)
#define XILINX_DMA_DMASR_SG_SLV_ERR             BIT(9)
#define XILINX_DMA_DMASR_EOF_EARLY_ERR          BIT(8)
#define XILINX_DMA_DMASR_SOF_EARLY_ERR          BIT(7)
#define XILINX_DMA_DMASR_DMA_DEC_ERR            BIT(6)
#define XILINX_DMA_DMASR_DMA_SLAVE_ERR          BIT(5)
#define XILINX_DMA_DMASR_DMA_INT_ERR            BIT(4)
#define XILINX_DMA_DMASR_IDLE                   BIT(1)
#define XILINX_DMA_DMASR_HALTED         BIT(0)
#define XILINX_DMA_DMASR_DELAY_MASK             GENMASK(31, 24)
#define XILINX_DMA_DMASR_FRAME_COUNT_MASK       GENMASK(23, 16)

#define XILINX_DMA_REG_CURDESC                  0x0008
#define XILINX_DMA_REG_TAILDESC         0x0010
#define XILINX_DMA_REG_REG_INDEX                0x0014
#define XILINX_DMA_REG_FRMSTORE         0x0018
#define XILINX_DMA_REG_THRESHOLD                0x001c
#define XILINX_DMA_REG_FRMPTR_STS               0x0024
#define XILINX_DMA_REG_PARK_PTR         0x0028
#define XILINX_DMA_PARK_PTR_WR_REF_SHIFT        8
#define XILINX_DMA_PARK_PTR_WR_REF_MASK         GENMASK(12, 8)
#define XILINX_DMA_PARK_PTR_RD_REF_SHIFT        0
#define XILINX_DMA_PARK_PTR_RD_REF_MASK         GENMASK(4, 0)
#define XILINX_DMA_REG_VDMA_VERSION             0x002c

/* Register Direct Mode Registers */
#define XILINX_DMA_REG_VSIZE                    0x0000
#define XILINX_DMA_REG_HSIZE                    0x0004

#define XILINX_DMA_REG_FRMDLY_STRIDE            0x0008
#define XILINX_DMA_FRMDLY_STRIDE_FRMDLY_SHIFT   24
#define XILINX_DMA_FRMDLY_STRIDE_STRIDE_SHIFT   0

#define XILINX_VDMA_REG_START_ADDRESS(n)        (0x000c + 4 * (n))
#define XILINX_VDMA_REG_START_ADDRESS_64(n)     (0x000c + 8 * (n))

#define XILINX_VDMA_REG_ENABLE_VERTICAL_FLIP    0x00ec
#define XILINX_VDMA_ENABLE_VERTICAL_FLIP        BIT(0)

/* HW specific definitions */
#define XILINX_DMA_MAX_CHANS_PER_DEVICE 0x2

#define XILINX_DMA_DMAXR_ALL_IRQ_MASK   \
                (XILINX_DMA_DMASR_FRM_CNT_IRQ | \
                 XILINX_DMA_DMASR_DLY_CNT_IRQ | \
                 XILINX_DMA_DMASR_ERR_IRQ)

#define XILINX_DMA_DMASR_ALL_ERR_MASK   \
                (XILINX_DMA_DMASR_EOL_LATE_ERR | \
                 XILINX_DMA_DMASR_SOF_LATE_ERR | \
                 XILINX_DMA_DMASR_SG_DEC_ERR | \
                 XILINX_DMA_DMASR_SG_SLV_ERR | \
                 XILINX_DMA_DMASR_EOF_EARLY_ERR | \
                 XILINX_DMA_DMASR_SOF_EARLY_ERR | \
                 XILINX_DMA_DMASR_DMA_DEC_ERR | \
                 XILINX_DMA_DMASR_DMA_SLAVE_ERR | \
                 XILINX_DMA_DMASR_DMA_INT_ERR)

/*
 * Recoverable errors are DMA Internal error, SOF Early, EOF Early
 * and SOF Late. They are only recoverable when C_FLUSH_ON_FSYNC
 * is enabled in the h/w system.
 */
#define XILINX_DMA_DMASR_ERR_RECOVER_MASK       \
                (XILINX_DMA_DMASR_SOF_LATE_ERR | \
                 XILINX_DMA_DMASR_EOF_EARLY_ERR | \
                 XILINX_DMA_DMASR_SOF_EARLY_ERR | \
                 XILINX_DMA_DMASR_DMA_INT_ERR)

/* Axi VDMA Flush on Fsync bits */
#define XILINX_DMA_FLUSH_S2MM           3
#define XILINX_DMA_FLUSH_MM2S           2
#define XILINX_DMA_FLUSH_BOTH           1

/* Delay loop counter to prevent hardware failure */
#define XILINX_DMA_LOOP_COUNT           1000000

/* AXI DMA Specific Registers/Offsets */
#define XILINX_DMA_REG_SRCDSTADDR       0x18
#define XILINX_DMA_REG_BTT              0x28

/* AXI DMA Specific Masks/Bit fields */
#define XILINX_DMA_MAX_TRANS_LEN_MIN    8
#define XILINX_DMA_MAX_TRANS_LEN_MAX    23
#define XILINX_DMA_V2_MAX_TRANS_LEN_MAX 26
#define XILINX_DMA_CR_COALESCE_MAX      GENMASK(23, 16)
#define XILINX_DMA_CR_CYCLIC_BD_EN_MASK BIT(4)
#define XILINX_DMA_CR_COALESCE_SHIFT    16
#define XILINX_DMA_BD_SOP               BIT(27)
#define XILINX_DMA_BD_EOP               BIT(26)
#define XILINX_DMA_COALESCE_MAX         255
#define XILINX_DMA_NUM_DESCS            255
#define XILINX_DMA_NUM_APP_WORDS        5

/* AXI CDMA Specific Registers/Offsets */
#define XILINX_CDMA_REG_SRCADDR         0x18
#define XILINX_CDMA_REG_DSTADDR         0x20

/* AXI CDMA Specific Masks */
#define XILINX_CDMA_CR_SGMODE          BIT(3)

#define xilinx_prep_dma_addr_t(addr)    \
        ((dma_addr_t)((u64)addr##_##msb << 32 | (addr)))
/**
 * struct xilinx_vdma_desc_hw - Hardware Descriptor
 * @next_desc: Next Descriptor Pointer @0x00
 * @pad1: Reserved @0x04
 * @buf_addr: Buffer address @0x08
 * @buf_addr_msb: MSB of Buffer address @0x0C
 * @vsize: Vertical Size @0x10
 * @hsize: Horizontal Size @0x14
 * @stride: Number of bytes between the first
 *          pixels of each horizontal line @0x18
 */
struct xilinx_vdma_desc_hw {
        u32 next_desc;
        u32 pad1;
        u32 buf_addr;
        u32 buf_addr_msb;
        u32 vsize;
        u32 hsize;
        u32 stride;
} __aligned(64);

/**
 * struct xilinx_axidma_desc_hw - Hardware Descriptor for AXI DMA
 * @next_desc: Next Descriptor Pointer @0x00
 * @next_desc_msb: MSB of Next Descriptor Pointer @0x04
 * @buf_addr: Buffer address @0x08
 * @buf_addr_msb: MSB of Buffer address @0x0C
 * @reserved1: Reserved @0x10
 * @reserved2: Reserved @0x14
 * @control: Control field @0x18
 * @status: Status field @0x1C
 * @app: APP Fields @0x20 - 0x30
 */
struct xilinx_axidma_desc_hw {
        u32 next_desc;
        u32 next_desc_msb;
        u32 buf_addr;
        u32 buf_addr_msb;
        u32 reserved1;
        u32 reserved2;
        u32 control;
        u32 status;
        u32 app[XILINX_DMA_NUM_APP_WORDS];
} __aligned(64);

/**
 * struct xilinx_cdma_desc_hw - Hardware Descriptor
 * @next_desc: Next Descriptor Pointer @0x00
 * @next_desc_msb: Next Descriptor Pointer MSB @0x04
 * @src_addr: Source address @0x08
 * @src_addr_msb: Source address MSB @0x0C
 * @dest_addr: Destination address @0x10
 * @dest_addr_msb: Destination address MSB @0x14
 * @control: Control field @0x18
 * @status: Status field @0x1C
 */
struct xilinx_cdma_desc_hw {
        u32 next_desc;
        u32 next_desc_msb;
        u32 src_addr;
        u32 src_addr_msb;
        u32 dest_addr;
        u32 dest_addr_msb;
        u32 control;
        u32 status;
} __aligned(64);

/**
 * struct xilinx_vdma_tx_segment - Descriptor segment
 * @hw: Hardware descriptor
 * @node: Node in the descriptor segments list
 * @phys: Physical address of segment
 */
struct xilinx_vdma_tx_segment {
        struct xilinx_vdma_desc_hw hw;
        struct list_head node;
        dma_addr_t phys;
} __aligned(64);

/**
 * struct xilinx_axidma_tx_segment - Descriptor segment
 * @hw: Hardware descriptor
 * @node: Node in the descriptor segments list
 * @phys: Physical address of segment
 */
struct xilinx_axidma_tx_segment {
        struct xilinx_axidma_desc_hw hw;
        struct list_head node;
        dma_addr_t phys;
} __aligned(64);

/**
 * struct xilinx_cdma_tx_segment - Descriptor segment
 * @hw: Hardware descriptor
 * @node: Node in the descriptor segments list
 * @phys: Physical address of segment
 */
struct xilinx_cdma_tx_segment {
        struct xilinx_cdma_desc_hw hw;
        struct list_head node;
        dma_addr_t phys;
} __aligned(64);

/**
 * struct xilinx_dma_tx_descriptor - Per Transaction structure
 * @async_tx: Async transaction descriptor
 * @segments: TX segments list
 * @node: Node in the channel descriptors list
 * @cyclic: Check for cyclic transfers.
 */
struct xilinx_dma_tx_descriptor {
        struct dma_async_tx_descriptor async_tx;
        struct list_head segments;
        struct list_head node;
        bool cyclic;
};

/**
 * struct xilinx_dma_chan - Driver specific DMA channel structure
 * @xdev: Driver specific device structure
 * @ctrl_offset: Control registers offset
 * @desc_offset: TX descriptor registers offset
 * @lock: Descriptor operation lock
 * @pending_list: Descriptors waiting
 * @active_list: Descriptors ready to submit
 * @done_list: Complete descriptors
 * @free_seg_list: Free descriptors
 * @common: DMA common channel
 * @desc_pool: Descriptors pool
 * @dev: The dma device
 * @irq: Channel IRQ
 * @id: Channel ID
 * @direction: Transfer direction
 * @num_frms: Number of frames
 * @has_sg: Support scatter transfers
 * @cyclic: Check for cyclic transfers.
 * @genlock: Support genlock mode
 * @err: Channel has errors
 * @idle: Check for channel idle
 * @tasklet: Cleanup work after irq
 * @config: Device configuration info
 * @flush_on_fsync: Flush on Frame sync
 * @desc_pendingcount: Descriptor pending count
 * @ext_addr: Indicates 64 bit addressing is supported by dma channel
 * @desc_submitcount: Descriptor h/w submitted count
 * @residue: Residue for AXI DMA
 * @seg_v: Statically allocated segments base
 * @seg_p: Physical allocated segments base
 * @cyclic_seg_v: Statically allocated segment base for cyclic transfers
 * @cyclic_seg_p: Physical allocated segments base for cyclic dma
 * @start_transfer: Differentiate b/w DMA IP's transfer
 * @stop_transfer: Differentiate b/w DMA IP's quiesce
 * @has_vflip: S2MM vertical flip
 */
struct xilinx_dma_chan {
        struct xilinx_dma_device *xdev;
        u32 ctrl_offset;
        u32 desc_offset;
        spinlock_t lock;
        struct list_head pending_list;
        struct list_head active_list;
        struct list_head done_list;
        struct list_head free_seg_list;
        struct dma_chan common;
        struct dma_pool *desc_pool;
        struct device *dev;
        int irq;
        int id;
        enum dma_transfer_direction direction;
        int num_frms;
        bool has_sg;
        bool cyclic;
        bool genlock;
        bool err;
        bool idle;
        struct tasklet_struct tasklet;
        struct xilinx_vdma_config config;
        bool flush_on_fsync;
        u32 desc_pendingcount;
        bool ext_addr;
        u32 desc_submitcount;
        u32 residue;
        struct xilinx_axidma_tx_segment *seg_v;
        dma_addr_t seg_p;
        struct xilinx_axidma_tx_segment *cyclic_seg_v;
        dma_addr_t cyclic_seg_p;
        void (*start_transfer)(struct xilinx_dma_chan *chan);
        int (*stop_transfer)(struct xilinx_dma_chan *chan);
        bool has_vflip;
};

/**
 * enum xdma_ip_type - DMA IP type.
 *
 * @XDMA_TYPE_AXIDMA: Axi dma ip.
 * @XDMA_TYPE_CDMA: Axi cdma ip.
 * @XDMA_TYPE_VDMA: Axi vdma ip.
 *
 */
enum xdma_ip_type {
        XDMA_TYPE_AXIDMA = 0,
        XDMA_TYPE_CDMA,
        XDMA_TYPE_VDMA,
};

struct xilinx_dma_config {
        enum xdma_ip_type dmatype;
        int (*clk_init)(struct platform_device *pdev, struct clk **axi_clk,
                        struct clk **tx_clk, struct clk **txs_clk,
                        struct clk **rx_clk, struct clk **rxs_clk);
};

/**
 * struct xilinx_dma_device - DMA device structure
 * @regs: I/O mapped base address
 * @dev: Device Structure
 * @common: DMA device structure
 * @chan: Driver specific DMA channel
 * @has_sg: Specifies whether Scatter-Gather is present or not
 * @flush_on_fsync: Flush on frame sync
 * @ext_addr: Indicates 64 bit addressing is supported by dma device
 * @pdev: Platform device structure pointer
 * @dma_config: DMA config structure
 * @axi_clk: DMA Axi4-lite interace clock
 * @tx_clk: DMA mm2s clock
 * @txs_clk: DMA mm2s stream clock
 * @rx_clk: DMA s2mm clock
 * @rxs_clk: DMA s2mm stream clock
 * @nr_channels: Number of channels DMA device supports
 * @chan_id: DMA channel identifier
 * @max_buffer_len: Max buffer length
 */
struct xilinx_dma_device {
        void __iomem *regs;
        struct device *dev;
        struct dma_device common;
        struct xilinx_dma_chan *chan[XILINX_DMA_MAX_CHANS_PER_DEVICE];
        bool has_sg;
        u32 flush_on_fsync;
        bool ext_addr;
        struct platform_device  *pdev;
        const struct xilinx_dma_config *dma_config;
        struct clk *axi_clk;
        struct clk *tx_clk;
        struct clk *txs_clk;
        struct clk *rx_clk;
        struct clk *rxs_clk;
        u32 nr_channels;
        u32 chan_id;
        u32 max_buffer_len;
};

/* Macros */
#define to_xilinx_chan(chan) \
        container_of(chan, struct xilinx_dma_chan, common)
#define to_dma_tx_descriptor(tx) \
        container_of(tx, struct xilinx_dma_tx_descriptor, async_tx)
#define xilinx_dma_poll_timeout(chan, reg, val, cond, delay_us, timeout_us) \
        readl_poll_timeout(chan->xdev->regs + chan->ctrl_offset + reg, val, \
                           cond, delay_us, timeout_us)

/* IO accessors */
static inline u32 dma_read(struct xilinx_dma_chan *chan, u32 reg)
{
        return ioread32(chan->xdev->regs + reg);
}

static inline void dma_write(struct xilinx_dma_chan *chan, u32 reg, u32 value)
{
        iowrite32(value, chan->xdev->regs + reg);
}

static inline void vdma_desc_write(struct xilinx_dma_chan *chan, u32 reg,
                                   u32 value)
{
        dma_write(chan, chan->desc_offset + reg, value);
}

static inline u32 dma_ctrl_read(struct xilinx_dma_chan *chan, u32 reg)
{
        return dma_read(chan, chan->ctrl_offset + reg);
}

static inline void dma_ctrl_write(struct xilinx_dma_chan *chan, u32 reg,
                                   u32 value)
{
        dma_write(chan, chan->ctrl_offset + reg, value);
}

static inline void dma_ctrl_clr(struct xilinx_dma_chan *chan, u32 reg,
                                 u32 clr)
{
        dma_ctrl_write(chan, reg, dma_ctrl_read(chan, reg) & ~clr);
}

static inline void dma_ctrl_set(struct xilinx_dma_chan *chan, u32 reg,
                                 u32 set)
{
        dma_ctrl_write(chan, reg, dma_ctrl_read(chan, reg) | set);
}

/**
 * vdma_desc_write_64 - 64-bit descriptor write
 * @chan: Driver specific VDMA channel
 * @reg: Register to write
 * @value_lsb: lower address of the descriptor.
 * @value_msb: upper address of the descriptor.
 *
 * Since vdma driver is trying to write to a register offset which is not a
 * multiple of 64 bits(ex : 0x5c), we are writing as two separate 32 bits
 * instead of a single 64 bit register write.
 */
static inline void vdma_desc_write_64(struct xilinx_dma_chan *chan, u32 reg,
                                      u32 value_lsb, u32 value_msb)
{
        /* Write the lsb 32 bits*/
        writel(value_lsb, chan->xdev->regs + chan->desc_offset + reg);

        /* Write the msb 32 bits */
        writel(value_msb, chan->xdev->regs + chan->desc_offset + reg + 4);
}

static inline void dma_writeq(struct xilinx_dma_chan *chan, u32 reg, u64 value)
{
        lo_hi_writeq(value, chan->xdev->regs + chan->ctrl_offset + reg);
}

static inline void xilinx_write(struct xilinx_dma_chan *chan, u32 reg,
                                dma_addr_t addr)
{
        if (chan->ext_addr)
                dma_writeq(chan, reg, addr);
        else
                dma_ctrl_write(chan, reg, addr);
}

static inline void xilinx_axidma_buf(struct xilinx_dma_chan *chan,
                                     struct xilinx_axidma_desc_hw *hw,
                                     dma_addr_t buf_addr, size_t sg_used,
                                     size_t period_len)
{
        if (chan->ext_addr) {
                hw->buf_addr = lower_32_bits(buf_addr + sg_used + period_len);
                hw->buf_addr_msb = upper_32_bits(buf_addr + sg_used +
                                                 period_len);
        } else {
                hw->buf_addr = buf_addr + sg_used + period_len;
        }
}

/* -----------------------------------------------------------------------------
 * Descriptors and segments alloc and free
 */

/**
 * xilinx_vdma_alloc_tx_segment - Allocate transaction segment
 * @chan: Driver specific DMA channel
 *
 * Return: The allocated segment on success and NULL on failure.
 */
static struct xilinx_vdma_tx_segment *
xilinx_vdma_alloc_tx_segment(struct xilinx_dma_chan *chan)
{
        struct xilinx_vdma_tx_segment *segment;
        dma_addr_t phys;

        segment = dma_pool_zalloc(chan->desc_pool, GFP_ATOMIC, &phys);
        if (!segment)
                return NULL;

        segment->phys = phys;

        return segment;
}

/**
 * xilinx_cdma_alloc_tx_segment - Allocate transaction segment
 * @chan: Driver specific DMA channel
 *
 * Return: The allocated segment on success and NULL on failure.
 */
static struct xilinx_cdma_tx_segment *
xilinx_cdma_alloc_tx_segment(struct xilinx_dma_chan *chan)
{
        struct xilinx_cdma_tx_segment *segment;
        dma_addr_t phys;

        segment = dma_pool_zalloc(chan->desc_pool, GFP_ATOMIC, &phys);
        if (!segment)
                return NULL;

        segment->phys = phys;

        return segment;
}

/**
 * xilinx_axidma_alloc_tx_segment - Allocate transaction segment
 * @chan: Driver specific DMA channel
 *
 * Return: The allocated segment on success and NULL on failure.
 */
static struct xilinx_axidma_tx_segment *
xilinx_axidma_alloc_tx_segment(struct xilinx_dma_chan *chan)
{
        struct xilinx_axidma_tx_segment *segment = NULL;
        unsigned long flags;

        spin_lock_irqsave(&chan->lock, flags);
        if (!list_empty(&chan->free_seg_list)) {
                segment = list_first_entry(&chan->free_seg_list,
                                           struct xilinx_axidma_tx_segment,
                                           node);
                list_del(&segment->node);
        }
        spin_unlock_irqrestore(&chan->lock, flags);

        return segment;
}

static void xilinx_dma_clean_hw_desc(struct xilinx_axidma_desc_hw *hw)
{
        u32 next_desc = hw->next_desc;
        u32 next_desc_msb = hw->next_desc_msb;

        memset(hw, 0, sizeof(struct xilinx_axidma_desc_hw));

        hw->next_desc = next_desc;
        hw->next_desc_msb = next_desc_msb;
}

/**
 * xilinx_dma_free_tx_segment - Free transaction segment
 * @chan: Driver specific DMA channel
 * @segment: DMA transaction segment
 */
static void xilinx_dma_free_tx_segment(struct xilinx_dma_chan *chan,
                                struct xilinx_axidma_tx_segment *segment)
{
        xilinx_dma_clean_hw_desc(&segment->hw);

        list_add_tail(&segment->node, &chan->free_seg_list);
}

/**
 * xilinx_cdma_free_tx_segment - Free transaction segment
 * @chan: Driver specific DMA channel
 * @segment: DMA transaction segment
 */
static void xilinx_cdma_free_tx_segment(struct xilinx_dma_chan *chan,
                                struct xilinx_cdma_tx_segment *segment)
{
        dma_pool_free(chan->desc_pool, segment, segment->phys);
}

/**
 * xilinx_vdma_free_tx_segment - Free transaction segment
 * @chan: Driver specific DMA channel
 * @segment: DMA transaction segment
 */
static void xilinx_vdma_free_tx_segment(struct xilinx_dma_chan *chan,
                                        struct xilinx_vdma_tx_segment *segment)
{
        dma_pool_free(chan->desc_pool, segment, segment->phys);
}

/**
 * xilinx_dma_tx_descriptor - Allocate transaction descriptor
 * @chan: Driver specific DMA channel
 *
 * Return: The allocated descriptor on success and NULL on failure.
 */
static struct xilinx_dma_tx_descriptor *
xilinx_dma_alloc_tx_descriptor(struct xilinx_dma_chan *chan)
{
        struct xilinx_dma_tx_descriptor *desc;

        desc = kzalloc(sizeof(*desc), GFP_KERNEL);
        if (!desc)
                return NULL;

        INIT_LIST_HEAD(&desc->segments);

        return desc;
}

/**
 * xilinx_dma_free_tx_descriptor - Free transaction descriptor
 * @chan: Driver specific DMA channel
 * @desc: DMA transaction descriptor
 */
static void
xilinx_dma_free_tx_descriptor(struct xilinx_dma_chan *chan,
                               struct xilinx_dma_tx_descriptor *desc)
{
        struct xilinx_vdma_tx_segment *segment, *next;
        struct xilinx_cdma_tx_segment *cdma_segment, *cdma_next;
        struct xilinx_axidma_tx_segment *axidma_segment, *axidma_next;

        if (!desc)
                return;

        if (chan->xdev->dma_config->dmatype == XDMA_TYPE_VDMA) {
                list_for_each_entry_safe(segment, next, &desc->segments, node) {
                        list_del(&segment->node);
                        xilinx_vdma_free_tx_segment(chan, segment);
                }
        } else if (chan->xdev->dma_config->dmatype == XDMA_TYPE_CDMA) {
                list_for_each_entry_safe(cdma_segment, cdma_next,
                                         &desc->segments, node) {
                        list_del(&cdma_segment->node);
                        xilinx_cdma_free_tx_segment(chan, cdma_segment);
                }
        } else {
                list_for_each_entry_safe(axidma_segment, axidma_next,
                                         &desc->segments, node) {
                        list_del(&axidma_segment->node);
                        xilinx_dma_free_tx_segment(chan, axidma_segment);
                }
        }

        kfree(desc);
}

/* Required functions */

/**
 * xilinx_dma_free_desc_list - Free descriptors list
 * @chan: Driver specific DMA channel
 * @list: List to parse and delete the descriptor
 */
static void xilinx_dma_free_desc_list(struct xilinx_dma_chan *chan,
                                        struct list_head *list)
{
        struct xilinx_dma_tx_descriptor *desc, *next;

        list_for_each_entry_safe(desc, next, list, node) {
                list_del(&desc->node);
                xilinx_dma_free_tx_descriptor(chan, desc);
        }
}

/**
 * xilinx_dma_free_descriptors - Free channel descriptors
 * @chan: Driver specific DMA channel
 */
static void xilinx_dma_free_descriptors(struct xilinx_dma_chan *chan)
{
        unsigned long flags;

        spin_lock_irqsave(&chan->lock, flags);

        xilinx_dma_free_desc_list(chan, &chan->pending_list);
        xilinx_dma_free_desc_list(chan, &chan->done_list);
        xilinx_dma_free_desc_list(chan, &chan->active_list);

        spin_unlock_irqrestore(&chan->lock, flags);
}

/**
 * xilinx_dma_free_chan_resources - Free channel resources
 * @dchan: DMA channel
 */
static void xilinx_dma_free_chan_resources(struct dma_chan *dchan)
{
        struct xilinx_dma_chan *chan = to_xilinx_chan(dchan);
        unsigned long flags;

        dev_dbg(chan->dev, "Free all channel resources.\n");

        xilinx_dma_free_descriptors(chan);

        if (chan->xdev->dma_config->dmatype == XDMA_TYPE_AXIDMA) {
                spin_lock_irqsave(&chan->lock, flags);
                INIT_LIST_HEAD(&chan->free_seg_list);
                spin_unlock_irqrestore(&chan->lock, flags);

                /* Free memory that is allocated for BD */
                dma_free_coherent(chan->dev, sizeof(*chan->seg_v) *
                                  XILINX_DMA_NUM_DESCS, chan->seg_v,
                                  chan->seg_p);

                /* Free Memory that is allocated for cyclic DMA Mode */
                dma_free_coherent(chan->dev, sizeof(*chan->cyclic_seg_v),
                                  chan->cyclic_seg_v, chan->cyclic_seg_p);
        }

        if (chan->xdev->dma_config->dmatype != XDMA_TYPE_AXIDMA) {
                dma_pool_destroy(chan->desc_pool);
                chan->desc_pool = NULL;
        }
}

/**
 * xilinx_dma_chan_handle_cyclic - Cyclic dma callback
 * @chan: Driver specific dma channel
 * @desc: dma transaction descriptor
 * @flags: flags for spin lock
 */
static void xilinx_dma_chan_handle_cyclic(struct xilinx_dma_chan *chan,
                                          struct xilinx_dma_tx_descriptor *desc,
                                          unsigned long *flags)
{
        dma_async_tx_callback callback;
        void *callback_param;

        callback = desc->async_tx.callback;
        callback_param = desc->async_tx.callback_param;
        if (callback) {
                spin_unlock_irqrestore(&chan->lock, *flags);
                callback(callback_param);
                spin_lock_irqsave(&chan->lock, *flags);
        }
}

/**
 * xilinx_dma_chan_desc_cleanup - Clean channel descriptors
 * @chan: Driver specific DMA channel
 */
static void xilinx_dma_chan_desc_cleanup(struct xilinx_dma_chan *chan)
{
        struct xilinx_dma_tx_descriptor *desc, *next;
        unsigned long flags;

        spin_lock_irqsave(&chan->lock, flags);

        list_for_each_entry_safe(desc, next, &chan->done_list, node) {
                struct dmaengine_desc_callback cb;

                if (desc->cyclic) {
                        xilinx_dma_chan_handle_cyclic(chan, desc, &flags);
                        break;
                }

                /* Remove from the list of running transactions */
                list_del(&desc->node);

                /* Run the link descriptor callback function */
                dmaengine_desc_get_callback(&desc->async_tx, &cb);
                if (dmaengine_desc_callback_valid(&cb)) {
                        spin_unlock_irqrestore(&chan->lock, flags);
                        dmaengine_desc_callback_invoke(&cb, NULL);
                        spin_lock_irqsave(&chan->lock, flags);
                }

                /* Run any dependencies, then free the descriptor */
                dma_run_dependencies(&desc->async_tx);
                xilinx_dma_free_tx_descriptor(chan, desc);
        }

        spin_unlock_irqrestore(&chan->lock, flags);
}

/**
 * xilinx_dma_do_tasklet - Schedule completion tasklet
 * @data: Pointer to the Xilinx DMA channel structure
 */
static void xilinx_dma_do_tasklet(unsigned long data)
{
        struct xilinx_dma_chan *chan = (struct xilinx_dma_chan *)data;

        xilinx_dma_chan_desc_cleanup(chan);
}

/**
 * xilinx_dma_alloc_chan_resources - Allocate channel resources
 * @dchan: DMA channel
 *
 * Return: '0' on success and failure value on error
 */
static int xilinx_dma_alloc_chan_resources(struct dma_chan *dchan)
{
        struct xilinx_dma_chan *chan = to_xilinx_chan(dchan);
        int i;

        /* Has this channel already been allocated? */
        if (chan->desc_pool)
                return 0;

        /*
         * We need the descriptor to be aligned to 64bytes
         * for meeting Xilinx VDMA specification requirement.
         */
        if (chan->xdev->dma_config->dmatype == XDMA_TYPE_AXIDMA) {
                /* Allocate the buffer descriptors. */
                chan->seg_v = dma_zalloc_coherent(chan->dev,
                                                  sizeof(*chan->seg_v) *
                                                  XILINX_DMA_NUM_DESCS,
                                                  &chan->seg_p, GFP_KERNEL);
                if (!chan->seg_v) {
                        dev_err(chan->dev,
                                "unable to allocate channel %d descriptors\n",
                                chan->id);
                        return -ENOMEM;
                }
                /*
                 * For cyclic DMA mode we need to program the tail Descriptor
                 * register with a value which is not a part of the BD chain
                 * so allocating a desc segment during channel allocation for
                 * programming tail descriptor.
                 */
                chan->cyclic_seg_v = dma_zalloc_coherent(chan->dev,
                                        sizeof(*chan->cyclic_seg_v),
                                        &chan->cyclic_seg_p, GFP_KERNEL);
                if (!chan->cyclic_seg_v) {
                        dev_err(chan->dev,
                                "unable to allocate desc segment for cyclic DMA\n");
                        dma_free_coherent(chan->dev, sizeof(*chan->seg_v) *
                                XILINX_DMA_NUM_DESCS, chan->seg_v,
                                chan->seg_p);
                        return -ENOMEM;
                }
                chan->cyclic_seg_v->phys = chan->cyclic_seg_p;

                for (i = 0; i < XILINX_DMA_NUM_DESCS; i++) {
                        chan->seg_v[i].hw.next_desc =
                        lower_32_bits(chan->seg_p + sizeof(*chan->seg_v) *
                                ((i + 1) % XILINX_DMA_NUM_DESCS));
                        chan->seg_v[i].hw.next_desc_msb =
                        upper_32_bits(chan->seg_p + sizeof(*chan->seg_v) *
                                ((i + 1) % XILINX_DMA_NUM_DESCS));
                        chan->seg_v[i].phys = chan->seg_p +
                                sizeof(*chan->seg_v) * i;
                        list_add_tail(&chan->seg_v[i].node,
                                      &chan->free_seg_list);
                }
        } else if (chan->xdev->dma_config->dmatype == XDMA_TYPE_CDMA) {
                chan->desc_pool = dma_pool_create("xilinx_cdma_desc_pool",
                                   chan->dev,
                                   sizeof(struct xilinx_cdma_tx_segment),
                                   __alignof__(struct xilinx_cdma_tx_segment),
                                   0);
        } else {
                chan->desc_pool = dma_pool_create("xilinx_vdma_desc_pool",
                                     chan->dev,
                                     sizeof(struct xilinx_vdma_tx_segment),
                                     __alignof__(struct xilinx_vdma_tx_segment),
                                     0);
        }

        if (!chan->desc_pool &&
            (chan->xdev->dma_config->dmatype != XDMA_TYPE_AXIDMA)) {
                dev_err(chan->dev,
                        "unable to allocate channel %d descriptor pool\n",
                        chan->id);
                return -ENOMEM;
        }

        dma_cookie_init(dchan);

        if (chan->xdev->dma_config->dmatype == XDMA_TYPE_AXIDMA) {
                /* For AXI DMA resetting once channel will reset the
                 * other channel as well so enable the interrupts here.
                 */
                dma_ctrl_set(chan, XILINX_DMA_REG_DMACR,
                              XILINX_DMA_DMAXR_ALL_IRQ_MASK);
        }

        if ((chan->xdev->dma_config->dmatype == XDMA_TYPE_CDMA) && chan->has_sg)
                dma_ctrl_set(chan, XILINX_DMA_REG_DMACR,
                             XILINX_CDMA_CR_SGMODE);

        return 0;
}

/**
 * xilinx_dma_tx_status - Get DMA transaction status
 * @dchan: DMA channel
 * @cookie: Transaction identifier
 * @txstate: Transaction state
 *
 * Return: DMA transaction status
 */
static enum dma_status xilinx_dma_tx_status(struct dma_chan *dchan,
                                        dma_cookie_t cookie,
                                        struct dma_tx_state *txstate)
{
        struct xilinx_dma_chan *chan = to_xilinx_chan(dchan);
        struct xilinx_dma_tx_descriptor *desc;
        struct xilinx_axidma_tx_segment *segment;
        struct xilinx_axidma_desc_hw *hw;
        enum dma_status ret;
        unsigned long flags;
        u32 residue = 0;

        ret = dma_cookie_status(dchan, cookie, txstate);
        if (ret == DMA_COMPLETE || !txstate)
                return ret;

        if (chan->xdev->dma_config->dmatype == XDMA_TYPE_AXIDMA) {
                spin_lock_irqsave(&chan->lock, flags);

                desc = list_last_entry(&chan->active_list,
                                       struct xilinx_dma_tx_descriptor, node);
                if (chan->has_sg) {
                        list_for_each_entry(segment, &desc->segments, node) {
                                hw = &segment->hw;
                                residue += (hw->control - hw->status) &
                                           chan->xdev->max_buffer_len;
                        }
                }
                spin_unlock_irqrestore(&chan->lock, flags);

                chan->residue = residue;
                dma_set_residue(txstate, chan->residue);
        }

        return ret;
}

/**
 * xilinx_dma_stop_transfer - Halt DMA channel
 * @chan: Driver specific DMA channel

 *
 * Return: '0' on success and failure value on error
 */
static int xilinx_dma_stop_transfer(struct xilinx_dma_chan *chan)
{
        u32 val;

        dma_ctrl_clr(chan, XILINX_DMA_REG_DMACR, XILINX_DMA_DMACR_RUNSTOP);

        /* Wait for the hardware to halt */
        return xilinx_dma_poll_timeout(chan, XILINX_DMA_REG_DMASR, val,
                                       val & XILINX_DMA_DMASR_HALTED, 0,
                                       XILINX_DMA_LOOP_COUNT);
}

/**
 * xilinx_cdma_stop_transfer - Wait for the current transfer to complete
 * @chan: Driver specific DMA channel
 *
 * Return: '0' on success and failure value on error
 */
static int xilinx_cdma_stop_transfer(struct xilinx_dma_chan *chan)
{
        u32 val;

        return xilinx_dma_poll_timeout(chan, XILINX_DMA_REG_DMASR, val,
                                       val & XILINX_DMA_DMASR_IDLE, 0,
                                       XILINX_DMA_LOOP_COUNT);
}

/**
 * xilinx_dma_start - Start DMA channel
 * @chan: Driver specific DMA channel
 */
static void xilinx_dma_start(struct xilinx_dma_chan *chan)
{
        int err;
        u32 val;

        dma_ctrl_set(chan, XILINX_DMA_REG_DMACR, XILINX_DMA_DMACR_RUNSTOP);

        /* Wait for the hardware to start */
        err = xilinx_dma_poll_timeout(chan, XILINX_DMA_REG_DMASR, val,
                                      !(val & XILINX_DMA_DMASR_HALTED), 0,
                                      XILINX_DMA_LOOP_COUNT);

        if (err) {
                dev_err(chan->dev, "Cannot start channel %p: %x\n",
                        chan, dma_ctrl_read(chan, XILINX_DMA_REG_DMASR));

                chan->err = true;
        }
}

/**
 * xilinx_vdma_start_transfer - Starts VDMA transfer
 * @chan: Driver specific channel struct pointer
 */
static void xilinx_vdma_start_transfer(struct xilinx_dma_chan *chan)
{
        struct xilinx_vdma_config *config = &chan->config;
        struct xilinx_dma_tx_descriptor *desc, *tail_desc;
        u32 reg, j;
        struct xilinx_vdma_tx_segment *tail_segment;

        /* This function was invoked with lock held */
        if (chan->err)
                return;

        if (!chan->idle)
                return;

        if (list_empty(&chan->pending_list))
                return;

        desc = list_first_entry(&chan->pending_list,
                                struct xilinx_dma_tx_descriptor, node);
        tail_desc = list_last_entry(&chan->pending_list,
                                    struct xilinx_dma_tx_descriptor, node);

        tail_segment = list_last_entry(&tail_desc->segments,
                                       struct xilinx_vdma_tx_segment, node);

        /*
         * If hardware is idle, then all descriptors on the running lists are
         * done, start new transfers
         */
        if (chan->has_sg)
                dma_ctrl_write(chan, XILINX_DMA_REG_CURDESC,
                                desc->async_tx.phys);

        /* Configure the hardware using info in the config structure */
        if (chan->has_vflip) {
                reg = dma_read(chan, XILINX_VDMA_REG_ENABLE_VERTICAL_FLIP);
                reg &= ~XILINX_VDMA_ENABLE_VERTICAL_FLIP;
                reg |= config->vflip_en;
                dma_write(chan, XILINX_VDMA_REG_ENABLE_VERTICAL_FLIP,
                          reg);
        }

        reg = dma_ctrl_read(chan, XILINX_DMA_REG_DMACR);

        if (config->frm_cnt_en)
                reg |= XILINX_DMA_DMACR_FRAMECNT_EN;
        else
                reg &= ~XILINX_DMA_DMACR_FRAMECNT_EN;

        /*
         * With SG, start with circular mode, so that BDs can be fetched.
         * In direct register mode, if not parking, enable circular mode
         */
        if (chan->has_sg || !config->park)
                reg |= XILINX_DMA_DMACR_CIRC_EN;

        if (config->park)
                reg &= ~XILINX_DMA_DMACR_CIRC_EN;

        dma_ctrl_write(chan, XILINX_DMA_REG_DMACR, reg);

        j = chan->desc_submitcount;
        reg = dma_read(chan, XILINX_DMA_REG_PARK_PTR);
        if (chan->direction == DMA_MEM_TO_DEV) {
                reg &= ~XILINX_DMA_PARK_PTR_RD_REF_MASK;
                reg |= j << XILINX_DMA_PARK_PTR_RD_REF_SHIFT;
        } else {
                reg &= ~XILINX_DMA_PARK_PTR_WR_REF_MASK;
                reg |= j << XILINX_DMA_PARK_PTR_WR_REF_SHIFT;
        }
        dma_write(chan, XILINX_DMA_REG_PARK_PTR, reg);

        /* Start the hardware */
        xilinx_dma_start(chan);

        if (chan->err)
                return;

        /* Start the transfer */
        if (chan->has_sg) {
                dma_ctrl_write(chan, XILINX_DMA_REG_TAILDESC,
                                tail_segment->phys);
                list_splice_tail_init(&chan->pending_list, &chan->active_list);
                chan->desc_pendingcount = 0;
        } else {
                struct xilinx_vdma_tx_segment *segment, *last = NULL;
                int i = 0;

                if (chan->desc_submitcount < chan->num_frms)
                        i = chan->desc_submitcount;

                list_for_each_entry(segment, &desc->segments, node) {
                        if (chan->ext_addr)
                                vdma_desc_write_64(chan,
                                        XILINX_VDMA_REG_START_ADDRESS_64(i++),
                                        segment->hw.buf_addr,
                                        segment->hw.buf_addr_msb);
                        else
                                vdma_desc_write(chan,
                                        XILINX_VDMA_REG_START_ADDRESS(i++),
                                        segment->hw.buf_addr);

                        last = segment;
                }

                if (!last)
                        return;

                /* HW expects these parameters to be same for one transaction */
                vdma_desc_write(chan, XILINX_DMA_REG_HSIZE, last->hw.hsize);
                vdma_desc_write(chan, XILINX_DMA_REG_FRMDLY_STRIDE,
                                last->hw.stride);
                vdma_desc_write(chan, XILINX_DMA_REG_VSIZE, last->hw.vsize);

                chan->desc_submitcount++;
                chan->desc_pendingcount--;
                list_del(&desc->node);
                list_add_tail(&desc->node, &chan->active_list);
                if (chan->desc_submitcount == chan->num_frms)
                        chan->desc_submitcount = 0;
        }

        chan->idle = false;
}

/**
 * xilinx_cdma_start_transfer - Starts cdma transfer
 * @chan: Driver specific channel struct pointer
 */
static void xilinx_cdma_start_transfer(struct xilinx_dma_chan *chan)
{
        struct xilinx_dma_tx_descriptor *head_desc, *tail_desc;
        struct xilinx_cdma_tx_segment *tail_segment;
        u32 ctrl_reg = dma_read(chan, XILINX_DMA_REG_DMACR);

        if (chan->err)
                return;

        if (!chan->idle)
                return;

        if (list_empty(&chan->pending_list))
                return;

        head_desc = list_first_entry(&chan->pending_list,
                                     struct xilinx_dma_tx_descriptor, node);
        tail_desc = list_last_entry(&chan->pending_list,
                                    struct xilinx_dma_tx_descriptor, node);
        tail_segment = list_last_entry(&tail_desc->segments,
                                       struct xilinx_cdma_tx_segment, node);

        if (chan->desc_pendingcount <= XILINX_DMA_COALESCE_MAX) {
                ctrl_reg &= ~XILINX_DMA_CR_COALESCE_MAX;
                ctrl_reg |= chan->desc_pendingcount <<
                                XILINX_DMA_CR_COALESCE_SHIFT;
                dma_ctrl_write(chan, XILINX_DMA_REG_DMACR, ctrl_reg);
        }

        if (chan->has_sg) {
                dma_ctrl_clr(chan, XILINX_DMA_REG_DMACR,
                             XILINX_CDMA_CR_SGMODE);

                dma_ctrl_set(chan, XILINX_DMA_REG_DMACR,
                             XILINX_CDMA_CR_SGMODE);

                xilinx_write(chan, XILINX_DMA_REG_CURDESC,
                             head_desc->async_tx.phys);

                /* Update tail ptr register which will start the transfer */
                xilinx_write(chan, XILINX_DMA_REG_TAILDESC,
                             tail_segment->phys);
        } else {
                /* In simple mode */
                struct xilinx_cdma_tx_segment *segment;
                struct xilinx_cdma_desc_hw *hw;

                segment = list_first_entry(&head_desc->segments,
                                           struct xilinx_cdma_tx_segment,
                                           node);

                hw = &segment->hw;

                xilinx_write(chan, XILINX_CDMA_REG_SRCADDR,
                             xilinx_prep_dma_addr_t(hw->src_addr));
                xilinx_write(chan, XILINX_CDMA_REG_DSTADDR,
                             xilinx_prep_dma_addr_t(hw->dest_addr));

                /* Start the transfer */
                dma_ctrl_write(chan, XILINX_DMA_REG_BTT,
                                hw->control & chan->xdev->max_buffer_len);
        }

        list_splice_tail_init(&chan->pending_list, &chan->active_list);
        chan->desc_pendingcount = 0;
        chan->idle = false;
}

/**
 * xilinx_dma_start_transfer - Starts DMA transfer
 * @chan: Driver specific channel struct pointer
 */
static void xilinx_dma_start_transfer(struct xilinx_dma_chan *chan)
{
        struct xilinx_dma_tx_descriptor *head_desc, *tail_desc;
        struct xilinx_axidma_tx_segment *tail_segment;
        u32 reg;

        if (chan->err)
                return;

        if (!chan->idle)
                return;

        if (list_empty(&chan->pending_list))
                return;

        head_desc = list_first_entry(&chan->pending_list,
                                     struct xilinx_dma_tx_descriptor, node);
        tail_desc = list_last_entry(&chan->pending_list,
                                    struct xilinx_dma_tx_descriptor, node);
        tail_segment = list_last_entry(&tail_desc->segments,
                                       struct xilinx_axidma_tx_segment, node);

        reg = dma_ctrl_read(chan, XILINX_DMA_REG_DMACR);

        if (chan->desc_pendingcount <= XILINX_DMA_COALESCE_MAX) {
                reg &= ~XILINX_DMA_CR_COALESCE_MAX;
                reg |= chan->desc_pendingcount <<
                                  XILINX_DMA_CR_COALESCE_SHIFT;
                dma_ctrl_write(chan, XILINX_DMA_REG_DMACR, reg);
        }

        if (chan->has_sg)
                xilinx_write(chan, XILINX_DMA_REG_CURDESC,
                             head_desc->async_tx.phys);

        xilinx_dma_start(chan);

        if (chan->err)
                return;

        /* Start the transfer */
        if (chan->has_sg) {
                if (chan->cyclic)
                        xilinx_write(chan, XILINX_DMA_REG_TAILDESC,
                                     chan->cyclic_seg_v->phys);
                else
                        xilinx_write(chan, XILINX_DMA_REG_TAILDESC,
                                     tail_segment->phys);
        } else {
                struct xilinx_axidma_tx_segment *segment;
                struct xilinx_axidma_desc_hw *hw;

                segment = list_first_entry(&head_desc->segments,
                                           struct xilinx_axidma_tx_segment,
                                           node);
                hw = &segment->hw;

                xilinx_write(chan, XILINX_DMA_REG_SRCDSTADDR,
                             xilinx_prep_dma_addr_t(hw->buf_addr));

                /* Start the transfer */
                dma_ctrl_write(chan, XILINX_DMA_REG_BTT,
                               hw->control & chan->xdev->max_buffer_len);
        }

        list_splice_tail_init(&chan->pending_list, &chan->active_list);
        chan->desc_pendingcount = 0;
        chan->idle = false;
}

/**
 * xilinx_dma_issue_pending - Issue pending transactions
 * @dchan: DMA channel
 */
static void xilinx_dma_issue_pending(struct dma_chan *dchan)
{
        struct xilinx_dma_chan *chan = to_xilinx_chan(dchan);
        unsigned long flags;

        spin_lock_irqsave(&chan->lock, flags);
        chan->start_transfer(chan);
        spin_unlock_irqrestore(&chan->lock, flags);
}

/**
 * xilinx_dma_complete_descriptor - Mark the active descriptor as complete
 * @chan : xilinx DMA channel
 *
 * CONTEXT: hardirq
 */
static void xilinx_dma_complete_descriptor(struct xilinx_dma_chan *chan)
{
        struct xilinx_dma_tx_descriptor *desc, *next;

        /* This function was invoked with lock held */
        if (list_empty(&chan->active_list))
                return;

        list_for_each_entry_safe(desc, next, &chan->active_list, node) {
                list_del(&desc->node);
                if (!desc->cyclic)
                        dma_cookie_complete(&desc->async_tx);
                list_add_tail(&desc->node, &chan->done_list);
        }
}

/**
 * xilinx_dma_reset - Reset DMA channel
 * @chan: Driver specific DMA channel
 *
 * Return: '0' on success and failure value on error
 */
static int xilinx_dma_reset(struct xilinx_dma_chan *chan)
{
        int err;
        u32 tmp;

        dma_ctrl_set(chan, XILINX_DMA_REG_DMACR, XILINX_DMA_DMACR_RESET);

        /* Wait for the hardware to finish reset */
        err = xilinx_dma_poll_timeout(chan, XILINX_DMA_REG_DMACR, tmp,
                                      !(tmp & XILINX_DMA_DMACR_RESET), 0,
                                      XILINX_DMA_LOOP_COUNT);

        if (err) {
                dev_err(chan->dev, "reset timeout, cr %x, sr %x\n",
                        dma_ctrl_read(chan, XILINX_DMA_REG_DMACR),
                        dma_ctrl_read(chan, XILINX_DMA_REG_DMASR));
                return -ETIMEDOUT;
        }

        chan->err = false;
        chan->idle = true;
        chan->desc_submitcount = 0;

        return err;
}

/**
 * xilinx_dma_chan_reset - Reset DMA channel and enable interrupts
 * @chan: Driver specific DMA channel
 *
 * Return: '0' on success and failure value on error
 */
static int xilinx_dma_chan_reset(struct xilinx_dma_chan *chan)
{
        int err;

        /* Reset VDMA */
        err = xilinx_dma_reset(chan);
        if (err)
                return err;

        /* Enable interrupts */
        dma_ctrl_set(chan, XILINX_DMA_REG_DMACR,
                      XILINX_DMA_DMAXR_ALL_IRQ_MASK);

        return 0;
}

/**
 * xilinx_dma_irq_handler - DMA Interrupt handler
 * @irq: IRQ number
 * @data: Pointer to the Xilinx DMA channel structure
 *
 * Return: IRQ_HANDLED/IRQ_NONE
 */
static irqreturn_t xilinx_dma_irq_handler(int irq, void *data)
{
        struct xilinx_dma_chan *chan = data;
        u32 status;

        /* Read the status and ack the interrupts. */
        status = dma_ctrl_read(chan, XILINX_DMA_REG_DMASR);
        if (!(status & XILINX_DMA_DMAXR_ALL_IRQ_MASK))
                return IRQ_NONE;

        dma_ctrl_write(chan, XILINX_DMA_REG_DMASR,
                        status & XILINX_DMA_DMAXR_ALL_IRQ_MASK);

        if (status & XILINX_DMA_DMASR_ERR_IRQ) {
                /*
                 * An error occurred. If C_FLUSH_ON_FSYNC is enabled and the
                 * error is recoverable, ignore it. Otherwise flag the error.
                 *
                 * Only recoverable errors can be cleared in the DMASR register,
                 * make sure not to write to other error bits to 1.
                 */
                u32 errors = status & XILINX_DMA_DMASR_ALL_ERR_MASK;

                dma_ctrl_write(chan, XILINX_DMA_REG_DMASR,
                                errors & XILINX_DMA_DMASR_ERR_RECOVER_MASK);

                if (!chan->flush_on_fsync ||
                    (errors & ~XILINX_DMA_DMASR_ERR_RECOVER_MASK)) {
                        dev_err(chan->dev,
                                "Channel %p has errors %x, cdr %x tdr %x\n",
                                chan, errors,
                                dma_ctrl_read(chan, XILINX_DMA_REG_CURDESC),
                                dma_ctrl_read(chan, XILINX_DMA_REG_TAILDESC));
                        chan->err = true;
                }
        }

        if (status & XILINX_DMA_DMASR_DLY_CNT_IRQ) {
                /*
                 * Device takes too long to do the transfer when user requires
                 * responsiveness.
                 */
                dev_dbg(chan->dev, "Inter-packet latency too long\n");
        }

        if (status & XILINX_DMA_DMASR_FRM_CNT_IRQ) {
                spin_lock(&chan->lock);
                xilinx_dma_complete_descriptor(chan);
                chan->idle = true;
                chan->start_transfer(chan);
                spin_unlock(&chan->lock);
        }

        tasklet_schedule(&chan->tasklet);
        return IRQ_HANDLED;
}

/**
 * append_desc_queue - Queuing descriptor
 * @chan: Driver specific dma channel
 * @desc: dma transaction descriptor
 */
static void append_desc_queue(struct xilinx_dma_chan *chan,
                              struct xilinx_dma_tx_descriptor *desc)
{
        struct xilinx_vdma_tx_segment *tail_segment;
        struct xilinx_dma_tx_descriptor *tail_desc;
        struct xilinx_axidma_tx_segment *axidma_tail_segment;
        struct xilinx_cdma_tx_segment *cdma_tail_segment;

        if (list_empty(&chan->pending_list))
                goto append;

        /*
         * Add the hardware descriptor to the chain of hardware descriptors
         * that already exists in memory.
         */
        tail_desc = list_last_entry(&chan->pending_list,
                                    struct xilinx_dma_tx_descriptor, node);
        if (chan->xdev->dma_config->dmatype == XDMA_TYPE_VDMA) {
                tail_segment = list_last_entry(&tail_desc->segments,
                                               struct xilinx_vdma_tx_segment,
                                               node);
                tail_segment->hw.next_desc = (u32)desc->async_tx.phys;
        } else if (chan->xdev->dma_config->dmatype == XDMA_TYPE_CDMA) {
                cdma_tail_segment = list_last_entry(&tail_desc->segments,
                                                struct xilinx_cdma_tx_segment,
                                                node);
                cdma_tail_segment->hw.next_desc = (u32)desc->async_tx.phys;
        } else {
                axidma_tail_segment = list_last_entry(&tail_desc->segments,
                                               struct xilinx_axidma_tx_segment,
                                               node);
                axidma_tail_segment->hw.next_desc = (u32)desc->async_tx.phys;
        }

        /*
         * Add the software descriptor and all children to the list
         * of pending transactions
         */
append:
        list_add_tail(&desc->node, &chan->pending_list);
        chan->desc_pendingcount++;

        if (chan->has_sg && (chan->xdev->dma_config->dmatype == XDMA_TYPE_VDMA)
            && unlikely(chan->desc_pendingcount > chan->num_frms)) {
                dev_dbg(chan->dev, "desc pendingcount is too high\n");
                chan->desc_pendingcount = chan->num_frms;
        }
}

/**
 * xilinx_dma_tx_submit - Submit DMA transaction
 * @tx: Async transaction descriptor
 *
 * Return: cookie value on success and failure value on error
 */
static dma_cookie_t xilinx_dma_tx_submit(struct dma_async_tx_descriptor *tx)
{
        struct xilinx_dma_tx_descriptor *desc = to_dma_tx_descriptor(tx);
        struct xilinx_dma_chan *chan = to_xilinx_chan(tx->chan);
        dma_cookie_t cookie;
        unsigned long flags;
        int err;

        if (chan->cyclic) {
                xilinx_dma_free_tx_descriptor(chan, desc);
                return -EBUSY;
        }

        if (chan->err) {
                /*
                 * If reset fails, need to hard reset the system.
                 * Channel is no longer functional
                 */
                err = xilinx_dma_chan_reset(chan);
                if (err < 0)
                        return err;
        }

        spin_lock_irqsave(&chan->lock, flags);

        cookie = dma_cookie_assign(tx);

        /* Put this transaction onto the tail of the pending queue */
        append_desc_queue(chan, desc);

        if (desc->cyclic)
                chan->cyclic = true;

        spin_unlock_irqrestore(&chan->lock, flags);

        return cookie;
}

/**
 * xilinx_vdma_dma_prep_interleaved - prepare a descriptor for a
 *      DMA_SLAVE transaction
 * @dchan: DMA channel
 * @xt: Interleaved template pointer
 * @flags: transfer ack flags
 *
 * Return: Async transaction descriptor on success and NULL on failure
 */
static struct dma_async_tx_descriptor *
xilinx_vdma_dma_prep_interleaved(struct dma_chan *dchan,
                                 struct dma_interleaved_template *xt,
                                 unsigned long flags)
{
        struct xilinx_dma_chan *chan = to_xilinx_chan(dchan);
        struct xilinx_dma_tx_descriptor *desc;
        struct xilinx_vdma_tx_segment *segment;
        struct xilinx_vdma_desc_hw *hw;

        if (!is_slave_direction(xt->dir))
                return NULL;

        if (!xt->numf || !xt->sgl[0].size)
                return NULL;

        if (xt->frame_size != 1)
                return NULL;

        /* Allocate a transaction descriptor. */
        desc = xilinx_dma_alloc_tx_descriptor(chan);
        if (!desc)
                return NULL;

        dma_async_tx_descriptor_init(&desc->async_tx, &chan->common);
        desc->async_tx.tx_submit = xilinx_dma_tx_submit;
        async_tx_ack(&desc->async_tx);

        /* Allocate the link descriptor from DMA pool */
        segment = xilinx_vdma_alloc_tx_segment(chan);
        if (!segment)
                goto error;

        /* Fill in the hardware descriptor */
        hw = &segment->hw;
        hw->vsize = xt->numf;
        hw->hsize = xt->sgl[0].size;
        hw->stride = (xt->sgl[0].icg + xt->sgl[0].size) <<
                        XILINX_DMA_FRMDLY_STRIDE_STRIDE_SHIFT;
        hw->stride |= chan->config.frm_dly <<
                        XILINX_DMA_FRMDLY_STRIDE_FRMDLY_SHIFT;

        if (xt->dir != DMA_MEM_TO_DEV) {
                if (chan->ext_addr) {
                        hw->buf_addr = lower_32_bits(xt->dst_start);
                        hw->buf_addr_msb = upper_32_bits(xt->dst_start);
                } else {
                        hw->buf_addr = xt->dst_start;
                }
        } else {
                if (chan->ext_addr) {
                        hw->buf_addr = lower_32_bits(xt->src_start);
                        hw->buf_addr_msb = upper_32_bits(xt->src_start);
                } else {
                        hw->buf_addr = xt->src_start;
                }
        }

        /* Insert the segment into the descriptor segments list. */
        list_add_tail(&segment->node, &desc->segments);

        /* Link the last hardware descriptor with the first. */
        segment = list_first_entry(&desc->segments,
                                   struct xilinx_vdma_tx_segment, node);
        desc->async_tx.phys = segment->phys;

        return &desc->async_tx;

error:
        xilinx_dma_free_tx_descriptor(chan, desc);
        return NULL;
}

/**
 * xilinx_cdma_prep_memcpy - prepare descriptors for a memcpy transaction
 * @dchan: DMA channel
 * @dma_dst: destination address
 * @dma_src: source address
 * @len: transfer length
 * @flags: transfer ack flags
 *
 * Return: Async transaction descriptor on success and NULL on failure
 */
static struct dma_async_tx_descriptor *
xilinx_cdma_prep_memcpy(struct dma_chan *dchan, dma_addr_t dma_dst,
                        dma_addr_t dma_src, size_t len, unsigned long flags)
{
        struct xilinx_dma_chan *chan = to_xilinx_chan(dchan);
        struct xilinx_dma_tx_descriptor *desc;
        struct xilinx_cdma_tx_segment *segment;
        struct xilinx_cdma_desc_hw *hw;

        if (!len || len > chan->xdev->max_buffer_len)
                return NULL;

        desc = xilinx_dma_alloc_tx_descriptor(chan);
        if (!desc)
                return NULL;

        dma_async_tx_descriptor_init(&desc->async_tx, &chan->common);
        desc->async_tx.tx_submit = xilinx_dma_tx_submit;

        /* Allocate the link descriptor from DMA pool */
        segment = xilinx_cdma_alloc_tx_segment(chan);
        if (!segment)
                goto error;

        hw = &segment->hw;
        hw->control = len;
        hw->src_addr = dma_src;
        hw->dest_addr = dma_dst;
        if (chan->ext_addr) {
                hw->src_addr_msb = upper_32_bits(dma_src);
                hw->dest_addr_msb = upper_32_bits(dma_dst);
        }

        /* Insert the segment into the descriptor segments list. */
        list_add_tail(&segment->node, &desc->segments);

        desc->async_tx.phys = segment->phys;
        hw->next_desc = segment->phys;

        return &desc->async_tx;

error:
        xilinx_dma_free_tx_descriptor(chan, desc);
        return NULL;
}

/**
 * xilinx_cdma_prep_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 *xilinx_cdma_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 xilinx_dma_chan *chan = to_xilinx_chan(dchan);
        struct xilinx_dma_tx_descriptor *desc;
        struct xilinx_cdma_tx_segment *segment, *prev = NULL;
        struct xilinx_cdma_desc_hw *hw;
        size_t len, dst_avail, src_avail;
        dma_addr_t dma_dst, dma_src;

        if (unlikely(dst_sg_len == 0 || src_sg_len == 0))
                return NULL;

        if (unlikely(dst_sg == NULL || src_sg == NULL))
                return NULL;

        desc = xilinx_dma_alloc_tx_descriptor(chan);
        if (!desc)
                return NULL;

        dma_async_tx_descriptor_init(&desc->async_tx, &chan->common);
        desc->async_tx.tx_submit = xilinx_dma_tx_submit;

        dst_avail = sg_dma_len(dst_sg);
        src_avail = sg_dma_len(src_sg);
        /*
         * loop until there is either no more source or no more destination
         * scatterlist entry
         */
        while (true) {
                len = min_t(size_t, src_avail, dst_avail);
                len = min_t(size_t, len, chan->xdev->max_buffer_len);
                if (len == 0)
                        goto fetch;

                /* Allocate the link descriptor from DMA pool */
                segment = xilinx_cdma_alloc_tx_segment(chan);
                if (!segment)
                        goto error;

                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;
                hw = &segment->hw;
                hw->control = len;
                hw->src_addr = dma_src;
                hw->dest_addr = dma_dst;
                if (chan->ext_addr) {
                        hw->src_addr_msb = upper_32_bits(dma_src);
                        hw->dest_addr_msb = upper_32_bits(dma_dst);
                }

                if (prev)
                        prev->hw.next_desc = segment->phys;

                prev = segment;
                dst_avail -= len;
                src_avail -= len;
                list_add_tail(&segment->node, &desc->segments);

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);
                }
        }

        /* Link the last hardware descriptor with the first. */
        segment = list_first_entry(&desc->segments,
                                struct xilinx_cdma_tx_segment, node);
        desc->async_tx.phys = segment->phys;
        prev->hw.next_desc = segment->phys;

        return &desc->async_tx;

error:
        xilinx_dma_free_tx_descriptor(chan, desc);
        return NULL;
}

/**
 * xilinx_dma_prep_slave_sg - prepare descriptors for a DMA_SLAVE transaction
 * @dchan: DMA channel
 * @sgl: scatterlist to transfer to/from
 * @sg_len: number of entries in @scatterlist
 * @direction: DMA direction
 * @flags: transfer ack flags
 * @context: APP words of the descriptor
 *
 * Return: Async transaction descriptor on success and NULL on failure
 */
static struct dma_async_tx_descriptor *xilinx_dma_prep_slave_sg(
        struct dma_chan *dchan, struct scatterlist *sgl, unsigned int sg_len,
        enum dma_transfer_direction direction, unsigned long flags,
        void *context)
{
        struct xilinx_dma_chan *chan = to_xilinx_chan(dchan);
        struct xilinx_dma_tx_descriptor *desc;
        struct xilinx_axidma_tx_segment *segment = NULL;
        u32 *app_w = (u32 *)context;
        struct scatterlist *sg;
        size_t copy;
        size_t sg_used;
        unsigned int i;

        if (!is_slave_direction(direction))
                return NULL;

        /* Allocate a transaction descriptor. */
        desc = xilinx_dma_alloc_tx_descriptor(chan);
        if (!desc)
                return NULL;

        dma_async_tx_descriptor_init(&desc->async_tx, &chan->common);
        desc->async_tx.tx_submit = xilinx_dma_tx_submit;

        /* Build transactions using information in the scatter gather list */
        for_each_sg(sgl, sg, sg_len, i) {
                sg_used = 0;

                /* Loop until the entire scatterlist entry is used */
                while (sg_used < sg_dma_len(sg)) {
                        struct xilinx_axidma_desc_hw *hw;

                        /* Get a free segment */
                        segment = xilinx_axidma_alloc_tx_segment(chan);
                        if (!segment)
                                goto error;

                        /*
                         * Calculate the maximum number of bytes to transfer,
                         * making sure it is less than the hw limit
                         */
                        copy = min_t(size_t, sg_dma_len(sg) - sg_used,
                                     chan->xdev->max_buffer_len);
                        hw = &segment->hw;

                        /* Fill in the descriptor */
                        xilinx_axidma_buf(chan, hw, sg_dma_address(sg),
                                          sg_used, 0);

                        hw->control = copy;

                        if (chan->direction == DMA_MEM_TO_DEV) {
                                if (app_w)
                                        memcpy(hw->app, app_w, sizeof(u32) *
                                               XILINX_DMA_NUM_APP_WORDS);
                        }

                        sg_used += copy;

                        /*
                         * Insert the segment into the descriptor segments
                         * list.
                         */
                        list_add_tail(&segment->node, &desc->segments);
                }
        }

        segment = list_first_entry(&desc->segments,
                                   struct xilinx_axidma_tx_segment, node);
        desc->async_tx.phys = segment->phys;

        /* For the last DMA_MEM_TO_DEV transfer, set EOP */
        if (chan->direction == DMA_MEM_TO_DEV) {
                segment->hw.control |= XILINX_DMA_BD_SOP;
                segment = list_last_entry(&desc->segments,
                                          struct xilinx_axidma_tx_segment,
                                          node);
                segment->hw.control |= XILINX_DMA_BD_EOP;
        }

        return &desc->async_tx;

error:
        xilinx_dma_free_tx_descriptor(chan, desc);
        return NULL;
}

/**
 * xilinx_dma_prep_dma_cyclic - prepare descriptors for a DMA_SLAVE transaction
 * @dchan: DMA channel
 * @buf_addr: Physical address of the buffer
 * @buf_len: Total length of the cyclic buffers
 * @period_len: length of individual cyclic buffer
 * @direction: DMA direction
 * @flags: transfer ack flags
 *
 * Return: Async transaction descriptor on success and NULL on failure
 */
static struct dma_async_tx_descriptor *xilinx_dma_prep_dma_cyclic(
        struct dma_chan *dchan, dma_addr_t buf_addr, size_t buf_len,
        size_t period_len, enum dma_transfer_direction direction,
        unsigned long flags)
{
        struct xilinx_dma_chan *chan = to_xilinx_chan(dchan);
        struct xilinx_dma_tx_descriptor *desc;
        struct xilinx_axidma_tx_segment *segment, *head_segment, *prev = NULL;
        size_t copy, sg_used;
        unsigned int num_periods;
        int i;
        u32 reg;

        if (!period_len)
                return NULL;

        num_periods = buf_len / period_len;

        if (!num_periods)
                return NULL;

        if (!is_slave_direction(direction))
                return NULL;

        /* Allocate a transaction descriptor. */
        desc = xilinx_dma_alloc_tx_descriptor(chan);
        if (!desc)
                return NULL;

        chan->direction = direction;
        dma_async_tx_descriptor_init(&desc->async_tx, &chan->common);
        desc->async_tx.tx_submit = xilinx_dma_tx_submit;

        for (i = 0; i < num_periods; ++i) {
                sg_used = 0;

                while (sg_used < period_len) {
                        struct xilinx_axidma_desc_hw *hw;

                        /* Get a free segment */
                        segment = xilinx_axidma_alloc_tx_segment(chan);
                        if (!segment)
                                goto error;

                        /*
                         * Calculate the maximum number of bytes to transfer,
                         * making sure it is less than the hw limit
                         */
                        copy = min_t(size_t, period_len - sg_used,
                                     chan->xdev->max_buffer_len);
                        hw = &segment->hw;
                        xilinx_axidma_buf(chan, hw, buf_addr, sg_used,
                                          period_len * i);
                        hw->control = copy;

                        if (prev)
                                prev->hw.next_desc = segment->phys;

                        prev = segment;
                        sg_used += copy;

                        /*
                         * Insert the segment into the descriptor segments
                         * list.
                         */
                        list_add_tail(&segment->node, &desc->segments);
                }
        }

        head_segment = list_first_entry(&desc->segments,
                                   struct xilinx_axidma_tx_segment, node);
        desc->async_tx.phys = head_segment->phys;

        desc->cyclic = true;
        reg = dma_ctrl_read(chan, XILINX_DMA_REG_DMACR);
        reg |= XILINX_DMA_CR_CYCLIC_BD_EN_MASK;
        dma_ctrl_write(chan, XILINX_DMA_REG_DMACR, reg);

        segment = list_last_entry(&desc->segments,
                                  struct xilinx_axidma_tx_segment,
                                  node);
        segment->hw.next_desc = (u32) head_segment->phys;

        /* For the last DMA_MEM_TO_DEV transfer, set EOP */
        if (direction == DMA_MEM_TO_DEV) {
                head_segment->hw.control |= XILINX_DMA_BD_SOP;
                segment->hw.control |= XILINX_DMA_BD_EOP;
        }

        return &desc->async_tx;

error:
        xilinx_dma_free_tx_descriptor(chan, desc);
        return NULL;
}

/**
 * xilinx_dma_terminate_all - Halt the channel and free descriptors
 * @dchan: Driver specific DMA Channel pointer
 *
 * Return: '0' always.
 */
static int xilinx_dma_terminate_all(struct dma_chan *dchan)
{
        struct xilinx_dma_chan *chan = to_xilinx_chan(dchan);
        u32 reg;
        int err;

        if (!chan->cyclic) {
                err = chan->stop_transfer(chan);
                if (err) {
                        dev_err(chan->dev, "Cannot stop channel %p: %x\n",
                                chan, dma_ctrl_read(chan,
                                XILINX_DMA_REG_DMASR));
                        chan->err = true;
                }
        }

        xilinx_dma_chan_reset(chan);
        /* Remove and free all of the descriptors in the lists */
        xilinx_dma_free_descriptors(chan);
        chan->idle = true;

        if (chan->cyclic) {
                reg = dma_ctrl_read(chan, XILINX_DMA_REG_DMACR);
                reg &= ~XILINX_DMA_CR_CYCLIC_BD_EN_MASK;
                dma_ctrl_write(chan, XILINX_DMA_REG_DMACR, reg);
                chan->cyclic = false;
        }

        if ((chan->xdev->dma_config->dmatype == XDMA_TYPE_CDMA) && chan->has_sg)
                dma_ctrl_clr(chan, XILINX_DMA_REG_DMACR,
                             XILINX_CDMA_CR_SGMODE);

        return 0;
}

/**
 * xilinx_dma_channel_set_config - Configure VDMA channel
 * Run-time configuration for Axi VDMA, supports:
 * . halt the channel
 * . configure interrupt coalescing and inter-packet delay threshold
 * . start/stop parking
 * . enable genlock
 *
 * @dchan: DMA channel
 * @cfg: VDMA device configuration pointer
 *
 * Return: '0' on success and failure value on error
 */
int xilinx_vdma_channel_set_config(struct dma_chan *dchan,
                                        struct xilinx_vdma_config *cfg)
{
        struct xilinx_dma_chan *chan = to_xilinx_chan(dchan);
        u32 dmacr;

        if (cfg->reset)
                return xilinx_dma_chan_reset(chan);

        dmacr = dma_ctrl_read(chan, XILINX_DMA_REG_DMACR);

        chan->config.frm_dly = cfg->frm_dly;
        chan->config.park = cfg->park;

        /* genlock settings */
        chan->config.gen_lock = cfg->gen_lock;
        chan->config.master = cfg->master;

        dmacr &= ~XILINX_DMA_DMACR_GENLOCK_EN;
        if (cfg->gen_lock && chan->genlock) {
                dmacr |= XILINX_DMA_DMACR_GENLOCK_EN;
                dmacr &= ~XILINX_DMA_DMACR_MASTER_MASK;
                dmacr |= cfg->master << XILINX_DMA_DMACR_MASTER_SHIFT;
        }

        chan->config.frm_cnt_en = cfg->frm_cnt_en;
        chan->config.vflip_en = cfg->vflip_en;

        if (cfg->park)
                chan->config.park_frm = cfg->park_frm;
        else
                chan->config.park_frm = -1;

        chan->config.coalesc = cfg->coalesc;
        chan->config.delay = cfg->delay;

        if (cfg->coalesc <= XILINX_DMA_DMACR_FRAME_COUNT_MAX) {
                dmacr &= ~XILINX_DMA_DMACR_FRAME_COUNT_MASK;
                dmacr |= cfg->coalesc << XILINX_DMA_DMACR_FRAME_COUNT_SHIFT;
                chan->config.coalesc = cfg->coalesc;
        }

        if (cfg->delay <= XILINX_DMA_DMACR_DELAY_MAX) {
                dmacr &= ~XILINX_DMA_DMACR_DELAY_MASK;
                dmacr |= cfg->delay << XILINX_DMA_DMACR_DELAY_SHIFT;
                chan->config.delay = cfg->delay;
        }

        /* FSync Source selection */
        dmacr &= ~XILINX_DMA_DMACR_FSYNCSRC_MASK;
        dmacr |= cfg->ext_fsync << XILINX_DMA_DMACR_FSYNCSRC_SHIFT;

        dma_ctrl_write(chan, XILINX_DMA_REG_DMACR, dmacr);

        return 0;
}
EXPORT_SYMBOL(xilinx_vdma_channel_set_config);

/* -----------------------------------------------------------------------------
 * Probe and remove
 */

/**
 * xilinx_dma_chan_remove - Per Channel remove function
 * @chan: Driver specific DMA channel
 */
static void xilinx_dma_chan_remove(struct xilinx_dma_chan *chan)
{
        /* Disable all interrupts */
        dma_ctrl_clr(chan, XILINX_DMA_REG_DMACR,
                      XILINX_DMA_DMAXR_ALL_IRQ_MASK);

        if (chan->irq > 0)
                free_irq(chan->irq, chan);

        tasklet_kill(&chan->tasklet);

        list_del(&chan->common.device_node);
}

static int axidma_clk_init(struct platform_device *pdev, struct clk **axi_clk,
                            struct clk **tx_clk, struct clk **rx_clk,
                            struct clk **sg_clk, struct clk **tmp_clk)
{
        int err;

        *tmp_clk = NULL;

        *axi_clk = devm_clk_get(&pdev->dev, "s_axi_lite_aclk");
        if (IS_ERR(*axi_clk)) {
                err = PTR_ERR(*axi_clk);
                dev_err(&pdev->dev, "failed to get axi_aclk (%d)\n", err);
                return err;
        }

        *tx_clk = devm_clk_get(&pdev->dev, "m_axi_mm2s_aclk");
        if (IS_ERR(*tx_clk))
                *tx_clk = NULL;

        *rx_clk = devm_clk_get(&pdev->dev, "m_axi_s2mm_aclk");
        if (IS_ERR(*rx_clk))
                *rx_clk = NULL;

        *sg_clk = devm_clk_get(&pdev->dev, "m_axi_sg_aclk");
        if (IS_ERR(*sg_clk))
                *sg_clk = NULL;

        err = clk_prepare_enable(*axi_clk);
        if (err) {
                dev_err(&pdev->dev, "failed to enable axi_clk (%d)\n", err);
                return err;
        }

        err = clk_prepare_enable(*tx_clk);
        if (err) {
                dev_err(&pdev->dev, "failed to enable tx_clk (%d)\n", err);
                goto err_disable_axiclk;
        }

        err = clk_prepare_enable(*rx_clk);
        if (err) {
                dev_err(&pdev->dev, "failed to enable rx_clk (%d)\n", err);
                goto err_disable_txclk;
        }

        err = clk_prepare_enable(*sg_clk);
        if (err) {
                dev_err(&pdev->dev, "failed to enable sg_clk (%d)\n", err);
                goto err_disable_rxclk;
        }

        return 0;

err_disable_rxclk:
        clk_disable_unprepare(*rx_clk);
err_disable_txclk:
        clk_disable_unprepare(*tx_clk);
err_disable_axiclk:
        clk_disable_unprepare(*axi_clk);

        return err;
}

static int axicdma_clk_init(struct platform_device *pdev, struct clk **axi_clk,
                            struct clk **dev_clk, struct clk **tmp_clk,
                            struct clk **tmp1_clk, struct clk **tmp2_clk)
{
        int err;

        *tmp_clk = NULL;
        *tmp1_clk = NULL;
        *tmp2_clk = NULL;

        *axi_clk = devm_clk_get(&pdev->dev, "s_axi_lite_aclk");
        if (IS_ERR(*axi_clk)) {
                err = PTR_ERR(*axi_clk);
                dev_err(&pdev->dev, "failed to get axi_clk (%d)\n", err);
                return err;
        }

        *dev_clk = devm_clk_get(&pdev->dev, "m_axi_aclk");
        if (IS_ERR(*dev_clk)) {
                err = PTR_ERR(*dev_clk);
                dev_err(&pdev->dev, "failed to get dev_clk (%d)\n", err);
                return err;
        }

        err = clk_prepare_enable(*axi_clk);
        if (err) {
                dev_err(&pdev->dev, "failed to enable axi_clk (%d)\n", err);
                return err;
        }

        err = clk_prepare_enable(*dev_clk);
        if (err) {
                dev_err(&pdev->dev, "failed to enable dev_clk (%d)\n", err);
                goto err_disable_axiclk;
        }

        return 0;

err_disable_axiclk:
        clk_disable_unprepare(*axi_clk);

        return err;
}

static int axivdma_clk_init(struct platform_device *pdev, struct clk **axi_clk,
                            struct clk **tx_clk, struct clk **txs_clk,
                            struct clk **rx_clk, struct clk **rxs_clk)
{
        int err;

        *axi_clk = devm_clk_get(&pdev->dev, "s_axi_lite_aclk");
        if (IS_ERR(*axi_clk)) {
                err = PTR_ERR(*axi_clk);
                dev_err(&pdev->dev, "failed to get axi_aclk (%d)\n", err);
                return err;
        }

        *tx_clk = devm_clk_get(&pdev->dev, "m_axi_mm2s_aclk");
        if (IS_ERR(*tx_clk))
                *tx_clk = NULL;

        *txs_clk = devm_clk_get(&pdev->dev, "m_axis_mm2s_aclk");
        if (IS_ERR(*txs_clk))
                *txs_clk = NULL;

        *rx_clk = devm_clk_get(&pdev->dev, "m_axi_s2mm_aclk");
        if (IS_ERR(*rx_clk))
                *rx_clk = NULL;

        *rxs_clk = devm_clk_get(&pdev->dev, "s_axis_s2mm_aclk");
        if (IS_ERR(*rxs_clk))
                *rxs_clk = NULL;

        err = clk_prepare_enable(*axi_clk);
        if (err) {
                dev_err(&pdev->dev, "failed to enable axi_clk (%d)\n", err);
                return err;
        }

        err = clk_prepare_enable(*tx_clk);
        if (err) {
                dev_err(&pdev->dev, "failed to enable tx_clk (%d)\n", err);
                goto err_disable_axiclk;
        }

        err = clk_prepare_enable(*txs_clk);
        if (err) {
                dev_err(&pdev->dev, "failed to enable txs_clk (%d)\n", err);
                goto err_disable_txclk;
        }

        err = clk_prepare_enable(*rx_clk);
        if (err) {
                dev_err(&pdev->dev, "failed to enable rx_clk (%d)\n", err);
                goto err_disable_txsclk;
        }

        err = clk_prepare_enable(*rxs_clk);
        if (err) {
                dev_err(&pdev->dev, "failed to enable rxs_clk (%d)\n", err);
                goto err_disable_rxclk;
        }

        return 0;

err_disable_rxclk:
        clk_disable_unprepare(*rx_clk);
err_disable_txsclk:
        clk_disable_unprepare(*txs_clk);
err_disable_txclk:
        clk_disable_unprepare(*tx_clk);
err_disable_axiclk:
        clk_disable_unprepare(*axi_clk);

        return err;
}

static void xdma_disable_allclks(struct xilinx_dma_device *xdev)
{
        clk_disable_unprepare(xdev->rxs_clk);
        clk_disable_unprepare(xdev->rx_clk);
        clk_disable_unprepare(xdev->txs_clk);
        clk_disable_unprepare(xdev->tx_clk);
        clk_disable_unprepare(xdev->axi_clk);
}

/**
 * xilinx_dma_chan_probe - Per Channel Probing
 * It get channel features from the device tree entry and
 * initialize special channel handling routines
 *
 * @xdev: Driver specific device structure
 * @node: Device node
 * @chan_id: DMA Channel id
 *
 * Return: '0' on success and failure value on error
 */
static int xilinx_dma_chan_probe(struct xilinx_dma_device *xdev,
                                  struct device_node *node, int chan_id)
{
        struct xilinx_dma_chan *chan;
        bool has_dre = false;
        u32 value, width;
        int err;

        /* Allocate and initialize the channel structure */
        chan = devm_kzalloc(xdev->dev, sizeof(*chan), GFP_KERNEL);
        if (!chan)
                return -ENOMEM;

        chan->dev = xdev->dev;
        chan->xdev = xdev;
        chan->has_sg = xdev->has_sg;
        chan->desc_pendingcount = 0x0;
        chan->ext_addr = xdev->ext_addr;
        /* This variable ensures that descriptors are not
         * Submitted when dma engine is in progress. This variable is
         * Added to avoid polling for a bit in the status register to
         * Know dma state in the driver hot path.
         */
        chan->idle = true;

        spin_lock_init(&chan->lock);
        INIT_LIST_HEAD(&chan->pending_list);
        INIT_LIST_HEAD(&chan->done_list);
        INIT_LIST_HEAD(&chan->active_list);
        INIT_LIST_HEAD(&chan->free_seg_list);

        /* Retrieve the channel properties from the device tree */
        has_dre = of_property_read_bool(node, "xlnx,include-dre");

        chan->genlock = of_property_read_bool(node, "xlnx,genlock-mode");

        err = of_property_read_u32(node, "xlnx,datawidth", &value);
        if (err) {
                dev_err(xdev->dev, "missing xlnx,datawidth property\n");
                return err;
        }
        width = value >> 3; /* Convert bits to bytes */

        /* If data width is greater than 8 bytes, DRE is not in hw */
        if (width > 8)
                has_dre = false;

        if (!has_dre)
                xdev->common.copy_align = fls(width - 1);

        if (of_device_is_compatible(node, "xlnx,axi-vdma-mm2s-channel") ||
            of_device_is_compatible(node, "xlnx,axi-dma-mm2s-channel") ||
            of_device_is_compatible(node, "xlnx,axi-cdma-channel")) {
                chan->direction = DMA_MEM_TO_DEV;
                chan->id = chan_id;
                xdev->common.directions = BIT(DMA_MEM_TO_DEV);

                chan->ctrl_offset = XILINX_DMA_MM2S_CTRL_OFFSET;
                if (xdev->dma_config->dmatype == XDMA_TYPE_VDMA) {
                        chan->desc_offset = XILINX_VDMA_MM2S_DESC_OFFSET;
                        chan->config.park = 1;

                        if (xdev->flush_on_fsync == XILINX_DMA_FLUSH_BOTH ||
                            xdev->flush_on_fsync == XILINX_DMA_FLUSH_MM2S)
                                chan->flush_on_fsync = true;
                }
        } else if (of_device_is_compatible(node,
                                           "xlnx,axi-vdma-s2mm-channel") ||
                   of_device_is_compatible(node,
                                           "xlnx,axi-dma-s2mm-channel")) {
                chan->direction = DMA_DEV_TO_MEM;
                chan->id = chan_id;
                xdev->common.directions |= BIT(DMA_DEV_TO_MEM);
                chan->has_vflip = of_property_read_bool(node,
                                        "xlnx,enable-vert-flip");
                if (chan->has_vflip) {
                        chan->config.vflip_en = dma_read(chan,
                                XILINX_VDMA_REG_ENABLE_VERTICAL_FLIP) &
                                XILINX_VDMA_ENABLE_VERTICAL_FLIP;
                }

                chan->ctrl_offset = XILINX_DMA_S2MM_CTRL_OFFSET;
                if (xdev->dma_config->dmatype == XDMA_TYPE_VDMA) {
                        chan->desc_offset = XILINX_VDMA_S2MM_DESC_OFFSET;
                        chan->config.park = 1;

                        if (xdev->flush_on_fsync == XILINX_DMA_FLUSH_BOTH ||
                            xdev->flush_on_fsync == XILINX_DMA_FLUSH_S2MM)
                                chan->flush_on_fsync = true;
                }
        } else {
                dev_err(xdev->dev, "Invalid channel compatible node\n");
                return -EINVAL;
        }

        /* Request the interrupt */
        chan->irq = irq_of_parse_and_map(node, 0);
        err = request_irq(chan->irq, xilinx_dma_irq_handler, IRQF_SHARED,
                          "xilinx-dma-controller", chan);
        if (err) {
                dev_err(xdev->dev, "unable to request IRQ %d\n", chan->irq);
                return err;
        }

        if (xdev->dma_config->dmatype == XDMA_TYPE_AXIDMA) {
                chan->start_transfer = xilinx_dma_start_transfer;
                chan->stop_transfer = xilinx_dma_stop_transfer;
        } else if (xdev->dma_config->dmatype == XDMA_TYPE_CDMA) {
                chan->start_transfer = xilinx_cdma_start_transfer;
                chan->stop_transfer = xilinx_cdma_stop_transfer;
        } else {
                chan->start_transfer = xilinx_vdma_start_transfer;
                chan->stop_transfer = xilinx_dma_stop_transfer;
        }

        /* Initialize the tasklet */
        tasklet_init(&chan->tasklet, xilinx_dma_do_tasklet,
                        (unsigned long)chan);

        /*
         * Initialize the DMA channel and add it to the DMA engine channels
         * list.
         */
        chan->common.device = &xdev->common;

        list_add_tail(&chan->common.device_node, &xdev->common.channels);
        xdev->chan[chan->id] = chan;

        /* Reset the channel */
        err = xilinx_dma_chan_reset(chan);
        if (err < 0) {
                dev_err(xdev->dev, "Reset channel failed\n");
                return err;
        }

        return 0;
}

/**
 * xilinx_dma_child_probe - Per child node probe
 * It get number of dma-channels per child node from
 * device-tree and initializes all the channels.
 *
 * @xdev: Driver specific device structure
 * @node: Device node
 *
 * Return: 0 always.
 */
static int xilinx_dma_child_probe(struct xilinx_dma_device *xdev,
                                    struct device_node *node)
{
        int i, nr_channels = 1;

        for (i = 0; i < nr_channels; i++)
                xilinx_dma_chan_probe(xdev, node, xdev->chan_id++);

        xdev->nr_channels += nr_channels;

        return 0;
}

/**
 * of_dma_xilinx_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_dma_xilinx_xlate(struct of_phandle_args *dma_spec,
                                                struct of_dma *ofdma)
{
        struct xilinx_dma_device *xdev = ofdma->of_dma_data;
        int chan_id = dma_spec->args[0];

        if (chan_id >= xdev->nr_channels || !xdev->chan[chan_id])
                return NULL;

        return dma_get_slave_channel(&xdev->chan[chan_id]->common);
}

static const struct xilinx_dma_config axidma_config = {
        .dmatype = XDMA_TYPE_AXIDMA,
        .clk_init = axidma_clk_init,
};

static const struct xilinx_dma_config axicdma_config = {
        .dmatype = XDMA_TYPE_CDMA,
        .clk_init = axicdma_clk_init,
};

static const struct xilinx_dma_config axivdma_config = {
        .dmatype = XDMA_TYPE_VDMA,
        .clk_init = axivdma_clk_init,
};

static const struct of_device_id xilinx_dma_of_ids[] = {
        { .compatible = "xlnx,axi-dma-1.00.a", .data = &axidma_config },
        { .compatible = "xlnx,axi-cdma-1.00.a", .data = &axicdma_config },
        { .compatible = "xlnx,axi-vdma-1.00.a", .data = &axivdma_config },
        {}
};
MODULE_DEVICE_TABLE(of, xilinx_dma_of_ids);

/**
 * xilinx_dma_probe - Driver probe function
 * @pdev: Pointer to the platform_device structure
 *
 * Return: '0' on success and failure value on error
 */
static int xilinx_dma_probe(struct platform_device *pdev)
{
        int (*clk_init)(struct platform_device *, struct clk **, struct clk **,
                        struct clk **, struct clk **, struct clk **)
                                        = axivdma_clk_init;
        struct device_node *node = pdev->dev.of_node;
        struct xilinx_dma_device *xdev;
        struct device_node *child, *np = pdev->dev.of_node;
        struct resource *io;
        u32 num_frames, addr_width, len_width;
        int i, err;

        /* Allocate and initialize the DMA engine structure */
        xdev = devm_kzalloc(&pdev->dev, sizeof(*xdev), GFP_KERNEL);
        if (!xdev)
                return -ENOMEM;

        xdev->dev = &pdev->dev;
        if (np) {
                const struct of_device_id *match;

                match = of_match_node(xilinx_dma_of_ids, np);
                if (match && match->data) {
                        xdev->dma_config = match->data;
                        clk_init = xdev->dma_config->clk_init;
                }
        }

        err = clk_init(pdev, &xdev->axi_clk, &xdev->tx_clk, &xdev->txs_clk,
                       &xdev->rx_clk, &xdev->rxs_clk);
        if (err)
                return err;

        /* Request and map I/O memory */
        io = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        xdev->regs = devm_ioremap_resource(&pdev->dev, io);
        if (IS_ERR(xdev->regs))
                return PTR_ERR(xdev->regs);

        /* Retrieve the DMA engine properties from the device tree */
        xdev->has_sg = of_property_read_bool(node, "xlnx,include-sg");
        xdev->max_buffer_len = GENMASK(XILINX_DMA_MAX_TRANS_LEN_MAX - 1, 0);

        if (xdev->dma_config->dmatype == XDMA_TYPE_AXIDMA) {
                if (!of_property_read_u32(node, "xlnx,sg-length-width",
                                          &len_width)) {
                        if (len_width < XILINX_DMA_MAX_TRANS_LEN_MIN ||
                            len_width > XILINX_DMA_V2_MAX_TRANS_LEN_MAX) {
                                dev_warn(xdev->dev,
                                         "invalid xlnx,sg-length-width property value using default width\n");
                        } else {
                                if (len_width > XILINX_DMA_MAX_TRANS_LEN_MAX)
                                        dev_warn(xdev->dev, "Please ensure that IP supports buffer length > 23 bits\n");

                                xdev->max_buffer_len = GENMASK(len_width - 1, 0);
                        }
                }
        }

        if (xdev->dma_config->dmatype == XDMA_TYPE_VDMA) {
                err = of_property_read_u32(node, "xlnx,num-fstores",
                                           &num_frames);
                if (err < 0) {
                        dev_err(xdev->dev,
                                "missing xlnx,num-fstores property\n");
                        return err;
                }

                err = of_property_read_u32(node, "xlnx,flush-fsync",
                                           &xdev->flush_on_fsync);
                if (err < 0)
                        dev_warn(xdev->dev,
                                 "missing xlnx,flush-fsync property\n");
        }

        err = of_property_read_u32(node, "xlnx,addrwidth", &addr_width);
        if (err < 0)
                dev_warn(xdev->dev, "missing xlnx,addrwidth property\n");

        if (addr_width > 32)
                xdev->ext_addr = true;
        else
                xdev->ext_addr = false;

        /* Set the dma mask bits */
        dma_set_mask(xdev->dev, DMA_BIT_MASK(addr_width));

        /* Initialize the DMA engine */
        xdev->common.dev = &pdev->dev;

        INIT_LIST_HEAD(&xdev->common.channels);
        if (!(xdev->dma_config->dmatype == XDMA_TYPE_CDMA)) {
                dma_cap_set(DMA_SLAVE, xdev->common.cap_mask);
                dma_cap_set(DMA_PRIVATE, xdev->common.cap_mask);
        }

        xdev->common.dst_addr_widths = BIT(addr_width / 8);
        xdev->common.src_addr_widths = BIT(addr_width / 8);
        xdev->common.device_alloc_chan_resources =
                                xilinx_dma_alloc_chan_resources;
        xdev->common.device_free_chan_resources =
                                xilinx_dma_free_chan_resources;
        xdev->common.device_terminate_all = xilinx_dma_terminate_all;
        xdev->common.device_tx_status = xilinx_dma_tx_status;
        xdev->common.device_issue_pending = xilinx_dma_issue_pending;
        if (xdev->dma_config->dmatype == XDMA_TYPE_AXIDMA) {
                dma_cap_set(DMA_CYCLIC, xdev->common.cap_mask);
                xdev->common.device_prep_slave_sg = xilinx_dma_prep_slave_sg;
                xdev->common.device_prep_dma_cyclic =
                                          xilinx_dma_prep_dma_cyclic;
                /* Residue calculation is supported by only AXI DMA */
                xdev->common.residue_granularity =
                                          DMA_RESIDUE_GRANULARITY_SEGMENT;
        } else if (xdev->dma_config->dmatype == XDMA_TYPE_CDMA) {
                dma_cap_set(DMA_MEMCPY, xdev->common.cap_mask);
                dma_cap_set(DMA_SG, xdev->common.cap_mask);
                xdev->common.device_prep_dma_memcpy = xilinx_cdma_prep_memcpy;
                xdev->common.device_prep_dma_sg = xilinx_cdma_prep_sg;
        } else {
                xdev->common.device_prep_interleaved_dma =
                                xilinx_vdma_dma_prep_interleaved;
        }

        platform_set_drvdata(pdev, xdev);

        /* Initialize the channels */
        for_each_child_of_node(node, child) {
                err = xilinx_dma_child_probe(xdev, child);
                if (err < 0)
                        goto disable_clks;
        }

        if (xdev->dma_config->dmatype == XDMA_TYPE_VDMA) {
                for (i = 0; i < xdev->nr_channels; i++)
                        if (xdev->chan[i])
                                xdev->chan[i]->num_frms = num_frames;
        }

        /* Register the DMA engine with the core */
        dma_async_device_register(&xdev->common);

        err = of_dma_controller_register(node, of_dma_xilinx_xlate,
                                         xdev);
        if (err < 0) {
                dev_err(&pdev->dev, "Unable to register DMA to DT\n");
                dma_async_device_unregister(&xdev->common);
                goto error;
        }

        if (xdev->dma_config->dmatype == XDMA_TYPE_AXIDMA)
                dev_info(&pdev->dev, "Xilinx AXI DMA Engine Driver Probed!!\n");
        else if (xdev->dma_config->dmatype == XDMA_TYPE_CDMA)
                dev_info(&pdev->dev, "Xilinx AXI CDMA Engine Driver Probed!!\n");
        else
                dev_info(&pdev->dev, "Xilinx AXI VDMA Engine Driver Probed!!\n");

        return 0;

disable_clks:
        xdma_disable_allclks(xdev);
error:
        for (i = 0; i < xdev->nr_channels; i++)
                if (xdev->chan[i])
                        xilinx_dma_chan_remove(xdev->chan[i]);

        return err;
}

/**
 * xilinx_dma_remove - Driver remove function
 * @pdev: Pointer to the platform_device structure
 *
 * Return: Always '0'
 */
static int xilinx_dma_remove(struct platform_device *pdev)
{
        struct xilinx_dma_device *xdev = platform_get_drvdata(pdev);
        int i;

        of_dma_controller_free(pdev->dev.of_node);

        dma_async_device_unregister(&xdev->common);

        for (i = 0; i < xdev->nr_channels; i++)
                if (xdev->chan[i])
                        xilinx_dma_chan_remove(xdev->chan[i]);

        xdma_disable_allclks(xdev);

        return 0;
}

static struct platform_driver xilinx_vdma_driver = {
        .driver = {
                .name = "xilinx-vdma",
                .of_match_table = xilinx_dma_of_ids,
        },
        .probe = xilinx_dma_probe,
        .remove = xilinx_dma_remove,
};

module_platform_driver(xilinx_vdma_driver);

MODULE_AUTHOR("Xilinx, Inc.");
MODULE_DESCRIPTION("Xilinx VDMA driver");
MODULE_LICENSE("GPL v2");