/*
 * Xilinx DPDMA Engine driver
 *
 *  Copyright (C) 2015 Xilinx, Inc.
 *
 *  Author: Hyun Woo Kwon <hyun.kwon@xilinx.com>
 *
 * This software is licensed under the terms of the GNU General Public
 * License version 2, as published by the Free Software Foundation, and
 * may be copied, distributed, and modified under those terms.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#include <linux/bitops.h>
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/dmaengine.h>
#include <linux/dmapool.h>
#include <linux/gfp.h>
#include <linux/interrupt.h>
#include <linux/irqreturn.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_dma.h>
#include <linux/platform_device.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/types.h>
#include <linux/wait.h>

#include "../dmaengine.h"

/* DPDMA registers */
#define XILINX_DPDMA_ERR_CTRL                           0x0
#define XILINX_DPDMA_ISR                                0x4
#define XILINX_DPDMA_IMR                                0x8
#define XILINX_DPDMA_IEN                                0xc
#define XILINX_DPDMA_IDS                                0x10
#define XILINX_DPDMA_INTR_DESC_DONE_MASK                (0x3f << 0)
#define XILINX_DPDMA_INTR_DESC_DONE_SHIFT               0
#define XILINX_DPDMA_INTR_NO_OSTAND_MASK                (0x3f << 6)
#define XILINX_DPDMA_INTR_NO_OSTAND_SHIFT               6
#define XILINX_DPDMA_INTR_AXI_ERR_MASK                  (0x3f << 12)
#define XILINX_DPDMA_INTR_AXI_ERR_SHIFT                 12
#define XILINX_DPDMA_INTR_DESC_ERR_MASK                 (0x3f << 18)
#define XILINX_DPDMA_INTR_DESC_ERR_SHIFT                16
#define XILINX_DPDMA_INTR_WR_CMD_FIFO_FULL              BIT(24)
#define XILINX_DPDMA_INTR_WR_DATA_FIFO_FULL             BIT(25)
#define XILINX_DPDMA_INTR_AXI_4K_CROSS                  BIT(26)
#define XILINX_DPDMA_INTR_VSYNC                         BIT(27)
#define XILINX_DPDMA_INTR_CHAN_ERR_MASK                 0x41000
#define XILINX_DPDMA_INTR_CHAN_ERR                      0xfff000
#define XILINX_DPDMA_INTR_GLOBAL_ERR                    0x7000000
#define XILINX_DPDMA_INTR_ERR_ALL                       0x7fff000
#define XILINX_DPDMA_INTR_CHAN_MASK                     0x41041
#define XILINX_DPDMA_INTR_GLOBAL_MASK                   0xf00000
#define XILINX_DPDMA_INTR_ALL                           0xfffffff
#define XILINX_DPDMA_EISR                               0x14
#define XILINX_DPDMA_EIMR                               0x18
#define XILINX_DPDMA_EIEN                               0x1c
#define XILINX_DPDMA_EIDS                               0x20
#define XILINX_DPDMA_EINTR_INV_APB                      BIT(0)
#define XILINX_DPDMA_EINTR_RD_AXI_ERR_MASK              (0x3f << 1)
#define XILINX_DPDMA_EINTR_RD_AXI_ERR_SHIFT             1
#define XILINX_DPDMA_EINTR_PRE_ERR_MASK                 (0x3f << 7)
#define XILINX_DPDMA_EINTR_PRE_ERR_SHIFT                7
#define XILINX_DPDMA_EINTR_CRC_ERR_MASK                 (0x3f << 13)
#define XILINX_DPDMA_EINTR_CRC_ERR_SHIFT                13
#define XILINX_DPDMA_EINTR_WR_AXI_ERR_MASK              (0x3f << 19)
#define XILINX_DPDMA_EINTR_WR_AXI_ERR_SHIFT             19
#define XILINX_DPDMA_EINTR_DESC_DONE_ERR_MASK           (0x3f << 25)
#define XILINX_DPDMA_EINTR_DESC_DONE_ERR_SHIFT          25
#define XILINX_DPDMA_EINTR_RD_CMD_FIFO_FULL             BIT(32)
#define XILINX_DPDMA_EINTR_CHAN_ERR_MASK                0x2082082
#define XILINX_DPDMA_EINTR_CHAN_ERR                     0x7ffffffe
#define XILINX_DPDMA_EINTR_GLOBAL_ERR                   0x80000001
#define XILINX_DPDMA_EINTR_ALL                          0xffffffff
#define XILINX_DPDMA_CNTL                               0x100
#define XILINX_DPDMA_GBL                                0x104
#define XILINX_DPDMA_GBL_TRIG_SHIFT                     0
#define XILINX_DPDMA_GBL_RETRIG_SHIFT                   6
#define XILINX_DPDMA_ALC0_CNTL                          0x108
#define XILINX_DPDMA_ALC0_STATUS                        0x10c
#define XILINX_DPDMA_ALC0_MAX                           0x110
#define XILINX_DPDMA_ALC0_MIN                           0x114
#define XILINX_DPDMA_ALC0_ACC                           0x118
#define XILINX_DPDMA_ALC0_ACC_TRAN                      0x11c
#define XILINX_DPDMA_ALC1_CNTL                          0x120
#define XILINX_DPDMA_ALC1_STATUS                        0x124
#define XILINX_DPDMA_ALC1_MAX                           0x128
#define XILINX_DPDMA_ALC1_MIN                           0x12c
#define XILINX_DPDMA_ALC1_ACC                           0x130
#define XILINX_DPDMA_ALC1_ACC_TRAN                      0x134

/* Channel register */
#define XILINX_DPDMA_CH_BASE                            0x200
#define XILINX_DPDMA_CH_OFFSET                          0x100
#define XILINX_DPDMA_CH_DESC_START_ADDRE                0x0
#define XILINX_DPDMA_CH_DESC_START_ADDR                 0x4
#define XILINX_DPDMA_CH_DESC_NEXT_ADDRE                 0x8
#define XILINX_DPDMA_CH_DESC_NEXT_ADDR                  0xc
#define XILINX_DPDMA_CH_PYLD_CUR_ADDRE                  0x10
#define XILINX_DPDMA_CH_PYLD_CUR_ADDR                   0x14
#define XILINX_DPDMA_CH_CNTL                            0x18
#define XILINX_DPDMA_CH_CNTL_ENABLE                     BIT(0)
#define XILINX_DPDMA_CH_CNTL_PAUSE                      BIT(1)
#define XILINX_DPDMA_CH_CNTL_QOS_DSCR_WR_SHIFT          2
#define XILINX_DPDMA_CH_CNTL_QOS_DSCR_RD_SHIFT          6
#define XILINX_DPDMA_CH_CNTL_QOS_DATA_RD_SHIFT          10
#define XILINX_DPDMA_CH_CNTL_QOS_VID_CLASS              11
#define XILINX_DPDMA_CH_STATUS                          0x1c
#define XILINX_DPDMA_CH_STATUS_OTRAN_CNT_MASK           (0xf << 21)
#define XILINX_DPDMA_CH_STATUS_OTRAN_CNT_SHIFT          21
#define XILINX_DPDMA_CH_VDO                             0x20
#define XILINX_DPDMA_CH_PYLD_SZ                         0x24
#define XILINX_DPDMA_CH_DESC_ID                         0x28

/* DPDMA descriptor fields */
#define XILINX_DPDMA_DESC_CONTROL_PREEMBLE              (0xa5)
#define XILINX_DPDMA_DESC_CONTROL_COMPLETE_INTR         BIT(8)
#define XILINX_DPDMA_DESC_CONTROL_DESC_UPDATE           BIT(9)
#define XILINX_DPDMA_DESC_CONTROL_IGNORE_DONE           BIT(10)
#define XILINX_DPDMA_DESC_CONTROL_FRAG_MODE             BIT(18)
#define XILINX_DPDMA_DESC_CONTROL_LAST                  BIT(19)
#define XILINX_DPDMA_DESC_CONTROL_ENABLE_CRC            BIT(20)
#define XILINX_DPDMA_DESC_CONTROL_LAST_OF_FRAME         BIT(21)
#define XILINX_DPDMA_DESC_ID_MASK                       (0xffff << 0)
#define XILINX_DPDMA_DESC_ID_SHIFT                      (0)
#define XILINX_DPDMA_DESC_HSIZE_STRIDE_HSIZE_MASK       (0x3ffff << 0)
#define XILINX_DPDMA_DESC_HSIZE_STRIDE_HSIZE_SHIFT      (0)
#define XILINX_DPDMA_DESC_HSIZE_STRIDE_STRIDE_MASK      (0x3fff << 18)
#define XILINX_DPDMA_DESC_HSIZE_STRIDE_STRIDE_SHIFT     (18)
#define XILINX_DPDMA_DESC_ADDR_EXT_ADDR_MASK            (0xfff)
#define XILINX_DPDMA_DESC_ADDR_EXT_ADDR_SHIFT           (16)

#define XILINX_DPDMA_ALIGN_BYTES                        256

#define XILINX_DPDMA_NUM_CHAN                           6
#define XILINX_DPDMA_PAGE_MASK                          ((1 << 12) - 1)
#define XILINX_DPDMA_PAGE_SHIFT                         12

/**
 * struct xilinx_dpdma_hw_desc - DPDMA hardware descriptor
 * @control: control configuration field
 * @desc_id: descriptor ID
 * @xfer_size: transfer size
 * @hsize_stride: horizontal size and stride
 * @timestamp_lsb: LSB of time stamp
 * @timestamp_msb: MSB of time stamp
 * @addr_ext: upper 16 bit of 48 bit address (next_desc and src_addr)
 * @next_desc: next descriptor 32 bit address
 * @src_addr: payload source address (lower 32 bit of 1st 4KB page)
 * @addr_ext_23: upper 16 bit of 48 bit address (src_addr2 and src_addr3)
 * @addr_ext_45: upper 16 bit of 48 bit address (src_addr4 and src_addr5)
 * @src_addr2: payload source address (lower 32 bit of 2nd 4KB page)
 * @src_addr3: payload source address (lower 32 bit of 3rd 4KB page)
 * @src_addr4: payload source address (lower 32 bit of 4th 4KB page)
 * @src_addr5: payload source address (lower 32 bit of 5th 4KB page)
 * @crc: descriptor CRC
 */
struct xilinx_dpdma_hw_desc {
        u32 control;
        u32 desc_id;
        u32 xfer_size;
        u32 hsize_stride;
        u32 timestamp_lsb;
        u32 timestamp_msb;
        u32 addr_ext;
        u32 next_desc;
        u32 src_addr;
        u32 addr_ext_23;
        u32 addr_ext_45;
        u32 src_addr2;
        u32 src_addr3;
        u32 src_addr4;
        u32 src_addr5;
        u32 crc;
} __aligned(XILINX_DPDMA_ALIGN_BYTES);

/**
 * struct xilinx_dpdma_sw_desc - DPDMA software descriptor
 * @hw: DPDMA hardware descriptor
 * @node: list node for software descriptors
 * @phys: physical address of the software descriptor
 */
struct xilinx_dpdma_sw_desc {
        struct xilinx_dpdma_hw_desc hw;
        struct list_head node;
        dma_addr_t phys;
};

/**
 * enum xilinx_dpdma_tx_desc_status - DPDMA tx descriptor status
 * @PREPARED: descriptor is prepared for transaction
 * @ACTIVE: transaction is (being) done successfully
 * @ERRORED: descriptor generates some errors
 */
enum xilinx_dpdma_tx_desc_status {
        PREPARED,
        ACTIVE,
        ERRORED
};

/**
 * struct xilinx_dpdma_tx_desc - DPDMA transaction descriptor
 * @async_tx: DMA async transaction descriptor
 * @descriptors: list of software descriptors
 * @node: list node for transaction descriptors
 * @status: tx descriptor status
 * @done_cnt: number of complete notification to deliver
 */
struct xilinx_dpdma_tx_desc {
        struct dma_async_tx_descriptor async_tx;
        struct list_head descriptors;
        struct list_head node;
        enum xilinx_dpdma_tx_desc_status status;
        unsigned int done_cnt;
};

/**
 * enum xilinx_dpdma_chan_id - DPDMA channel ID
 * @VIDEO0: video 1st channel
 * @VIDEO1: video 2nd channel for multi plane yuv formats
 * @VIDEO2: video 3rd channel for multi plane yuv formats
 * @GRAPHICS: graphics channel
 * @AUDIO0: 1st audio channel
 * @AUDIO1: 2nd audio channel
 */
enum xilinx_dpdma_chan_id {
        VIDEO0,
        VIDEO1,
        VIDEO2,
        GRAPHICS,
        AUDIO0,
        AUDIO1
};

/**
 * enum xilinx_dpdma_chan_status - DPDMA channel status
 * @IDLE: idle state
 * @STREAMING: actively streaming state
 */
enum xilinx_dpdma_chan_status {
        IDLE,
        STREAMING
};

/*
 * DPDMA descriptor placement
 * --------------------------
 * DPDMA descritpor life time is described with following placements:
 *
 * allocated_desc -> submitted_desc -> pending_desc -> active_desc -> done_list
 *
 * Transition is triggered as following:
 *
 * -> allocated_desc : a descriptor allocation
 * allocated_desc -> submitted_desc: a descriptorsubmission
 * submitted_desc -> pending_desc: request to issue pending a descriptor
 * pending_desc -> active_desc: VSYNC intr when a desc is scheduled to DPDMA
 * active_desc -> done_list: VSYNC intr when DPDMA switches to a new desc
 */

/**
 * struct xilinx_dpdma_chan - DPDMA channel
 * @common: generic dma channel structure
 * @reg: register base address
 * @id: channel ID
 * @wait_to_stop: queue to wait for outstanding transacitons before stopping
 * @status: channel status
 * @first_frame: flag for the first frame of stream
 * @video_group: flag if multi-channel operation is needed for video channels
 * @lock: lock to access struct xilinx_dpdma_chan
 * @desc_pool: descriptor allocation pool
 * @done_task: done IRQ bottom half handler
 * @err_task: error IRQ bottom half handler
 * @allocated_desc: allocated descriptor
 * @submitted_desc: submitted descriptor
 * @pending_desc: pending descriptor to be scheduled in next period
 * @active_desc: descriptor that the DPDMA channel is active on
 * @done_list: done descriptor list
 * @xdev: DPDMA device
 */
struct xilinx_dpdma_chan {
        struct dma_chan common;
        void __iomem *reg;
        enum xilinx_dpdma_chan_id id;

        wait_queue_head_t wait_to_stop;
        enum xilinx_dpdma_chan_status status;
        bool first_frame;
        bool video_group;

        spinlock_t lock;
        struct dma_pool *desc_pool;
        struct tasklet_struct done_task;
        struct tasklet_struct err_task;

        struct xilinx_dpdma_tx_desc *allocated_desc;
        struct xilinx_dpdma_tx_desc *submitted_desc;
        struct xilinx_dpdma_tx_desc *pending_desc;
        struct xilinx_dpdma_tx_desc *active_desc;
        struct list_head done_list;

        struct xilinx_dpdma_device *xdev;
};

/**
 * struct xilinx_dpdma_device - DPDMA device
 * @common: generic dma device structure
 * @reg: register base address
 * @dev: generic device structure
 * @axi_clk: axi clock
 * @chan: DPDMA channels
 * @ext_addr: flag for 64 bit system (48 bit addressing)
 * @desc_addr: descriptor addressing callback (32 bit vs 64 bit)
 */
struct xilinx_dpdma_device {
        struct dma_device common;
        void __iomem *reg;
        struct device *dev;

        struct clk *axi_clk;
        struct xilinx_dpdma_chan *chan[XILINX_DPDMA_NUM_CHAN];

        bool ext_addr;
        void (*desc_addr)(struct xilinx_dpdma_sw_desc *sw_desc,
                          struct xilinx_dpdma_sw_desc *prev,
                          dma_addr_t dma_addr[], unsigned int num_src_addr);
};

#define to_dpdma_tx_desc(tx) \
        container_of(tx, struct xilinx_dpdma_tx_desc, async_tx)

#define to_xilinx_chan(chan) \
        container_of(chan, struct xilinx_dpdma_chan, common)

/* IO operations */

static inline u32 dpdma_read(void __iomem *base, u32 offset)
{
        return ioread32(base + offset);
}

static inline void dpdma_write(void __iomem *base, u32 offset, u32 val)
{
        iowrite32(val, base + offset);
}

static inline void dpdma_clr(void __iomem *base, u32 offset, u32 clr)
{
        dpdma_write(base, offset, dpdma_read(base, offset) & ~clr);
}

static inline void dpdma_set(void __iomem *base, u32 offset, u32 set)
{
        dpdma_write(base, offset, dpdma_read(base, offset) | set);
}

/* Xilinx DPDMA descriptor operations */

/**
 * xilinx_dpdma_sw_desc_next_32 - Set 32 bit address of a next sw descriptor
 * @sw_desc: current software descriptor
 * @next: next descriptor
 *
 * Update the current sw descriptor @sw_desc with 32 bit address of the next
 * descriptor @next.
 */
static inline void
xilinx_dpdma_sw_desc_next_32(struct xilinx_dpdma_sw_desc *sw_desc,
                             struct xilinx_dpdma_sw_desc *next)
{
        sw_desc->hw.next_desc = next->phys;
}

/**
 * xilinx_dpdma_sw_desc_addr_32 - Update the sw descriptor with 32 bit address
 * @sw_desc: software descriptor
 * @prev: previous descriptor
 * @dma_addr: array of dma addresses
 * @num_src_addr: number of addresses in @dma_addr
 *
 * Update the descriptor @sw_desc with 32 bit address.
 */
static void xilinx_dpdma_sw_desc_addr_32(struct xilinx_dpdma_sw_desc *sw_desc,
                                         struct xilinx_dpdma_sw_desc *prev,
                                         dma_addr_t dma_addr[],
                                         unsigned int num_src_addr)
{
        struct xilinx_dpdma_hw_desc *hw_desc = &sw_desc->hw;
        unsigned int i;

        hw_desc->src_addr = dma_addr[0];

        if (prev)
                xilinx_dpdma_sw_desc_next_32(prev, sw_desc);

        for (i = 1; i < num_src_addr; i++) {
                u32 *addr = &hw_desc->src_addr2;
                u32 frag_addr;

                frag_addr = dma_addr[i];
                addr[i - 1] = frag_addr;
        }
}

/**
 * xilinx_dpdma_sw_desc_next_64 - Set 64 bit address of a next sw descriptor
 * @sw_desc: current software descriptor
 * @next: next descriptor
 *
 * Update the current sw descriptor @sw_desc with 64 bit address of the next
 * descriptor @next.
 */
static inline void
xilinx_dpdma_sw_desc_next_64(struct xilinx_dpdma_sw_desc *sw_desc,
                             struct xilinx_dpdma_sw_desc *next)
{
        sw_desc->hw.next_desc = (u32)next->phys;
        sw_desc->hw.addr_ext |= ((u64)next->phys >> 32) &
                                XILINX_DPDMA_DESC_ADDR_EXT_ADDR_MASK;
}

/**
 * xilinx_dpdma_sw_desc_addr_64 - Update the sw descriptor with 64 bit address
 * @sw_desc: software descriptor
 * @prev: previous descriptor
 * @dma_addr: array of dma addresses
 * @num_src_addr: number of addresses in @dma_addr
 *
 * Update the descriptor @sw_desc with 64 bit address.
 */
static void xilinx_dpdma_sw_desc_addr_64(struct xilinx_dpdma_sw_desc *sw_desc,
                                         struct xilinx_dpdma_sw_desc *prev,
                                         dma_addr_t dma_addr[],
                                         unsigned int num_src_addr)
{
        struct xilinx_dpdma_hw_desc *hw_desc = &sw_desc->hw;
        unsigned int i;

        hw_desc->src_addr = (u32)dma_addr[0];
        hw_desc->addr_ext |=
                ((u64)dma_addr[0] >> 32) & XILINX_DPDMA_DESC_ADDR_EXT_ADDR_MASK;

        if (prev)
                xilinx_dpdma_sw_desc_next_64(prev, sw_desc);

        for (i = 1; i < num_src_addr; i++) {
                u32 *addr = &hw_desc->src_addr2;
                u32 *addr_ext = &hw_desc->addr_ext_23;
                u64 frag_addr;

                frag_addr = dma_addr[i];
                addr[i] = (u32)frag_addr;

                frag_addr >>= 32;
                frag_addr &= XILINX_DPDMA_DESC_ADDR_EXT_ADDR_MASK;
                frag_addr <<= XILINX_DPDMA_DESC_ADDR_EXT_ADDR_SHIFT * (i % 2);
                addr_ext[i / 2] = frag_addr;
        }
}

/* Xilinx DPDMA channel descriptor operations */

/**
 * xilinx_dpdma_chan_alloc_sw_desc - Allocate a software descriptor
 * @chan: DPDMA channel
 *
 * Allocate a software descriptor from the channel's descriptor pool.
 *
 * Return: a software descriptor or NULL.
 */
static struct xilinx_dpdma_sw_desc *
xilinx_dpdma_chan_alloc_sw_desc(struct xilinx_dpdma_chan *chan)
{
        struct xilinx_dpdma_sw_desc *sw_desc;
        dma_addr_t phys;

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

        memset(sw_desc, 0, sizeof(*sw_desc));
        sw_desc->phys = phys;

        return sw_desc;
}

/**
 * xilinx_dpdma_chan_free_sw_desc - Free a software descriptor
 * @chan: DPDMA channel
 * @sw_desc: software descriptor to free
 *
 * Free a software descriptor from the channel's descriptor pool.
 */
static void
xilinx_dpdma_chan_free_sw_desc(struct xilinx_dpdma_chan *chan,
                               struct xilinx_dpdma_sw_desc *sw_desc)
{
        dma_pool_free(chan->desc_pool, sw_desc, sw_desc->phys);
}

/**
 * xilinx_dpdma_chan_dump_tx_desc - Dump a tx descriptor
 * @chan: DPDMA channel
 * @tx_desc: tx descriptor to dump
 *
 * Dump contents of a tx descriptor
 */
static void xilinx_dpdma_chan_dump_tx_desc(struct xilinx_dpdma_chan *chan,
                                           struct xilinx_dpdma_tx_desc *tx_desc)
{
        struct xilinx_dpdma_sw_desc *sw_desc;
        struct device *dev = chan->xdev->dev;
        unsigned int i = 0;

        dev_dbg(dev, "------- TX descriptor dump start -------\n");
        dev_dbg(dev, "------- channel ID = %d -------\n", chan->id);

        list_for_each_entry(sw_desc, &tx_desc->descriptors, node) {
                struct xilinx_dpdma_hw_desc *hw_desc = &sw_desc->hw;

                dev_dbg(dev, "------- HW descriptor %d -------\n", i++);
                dev_dbg(dev, "descriptor phys: %pad\n", &sw_desc->phys);
                dev_dbg(dev, "control: 0x%08x\n", hw_desc->control);
                dev_dbg(dev, "desc_id: 0x%08x\n", hw_desc->desc_id);
                dev_dbg(dev, "xfer_size: 0x%08x\n", hw_desc->xfer_size);
                dev_dbg(dev, "hsize_stride: 0x%08x\n", hw_desc->hsize_stride);
                dev_dbg(dev, "timestamp_lsb: 0x%08x\n", hw_desc->timestamp_lsb);
                dev_dbg(dev, "timestamp_msb: 0x%08x\n", hw_desc->timestamp_msb);
                dev_dbg(dev, "addr_ext: 0x%08x\n", hw_desc->addr_ext);
                dev_dbg(dev, "next_desc: 0x%08x\n", hw_desc->next_desc);
                dev_dbg(dev, "src_addr: 0x%08x\n", hw_desc->src_addr);
                dev_dbg(dev, "addr_ext_23: 0x%08x\n", hw_desc->addr_ext_23);
                dev_dbg(dev, "addr_ext_45: 0x%08x\n", hw_desc->addr_ext_45);
                dev_dbg(dev, "src_addr2: 0x%08x\n", hw_desc->src_addr2);
                dev_dbg(dev, "src_addr3: 0x%08x\n", hw_desc->src_addr3);
                dev_dbg(dev, "src_addr4: 0x%08x\n", hw_desc->src_addr4);
                dev_dbg(dev, "src_addr5: 0x%08x\n", hw_desc->src_addr5);
                dev_dbg(dev, "crc: 0x%08x\n", hw_desc->crc);
        }

        dev_dbg(dev, "------- TX descriptor dump end -------\n");
}

/**
 * xilinx_dpdma_chan_alloc_tx_desc - Allocate a transaction descriptor
 * @chan: DPDMA channel
 *
 * Allocate a tx descriptor.
 *
 * Return: a tx descriptor or NULL.
 */
static struct xilinx_dpdma_tx_desc *
xilinx_dpdma_chan_alloc_tx_desc(struct xilinx_dpdma_chan *chan)
{
        struct xilinx_dpdma_tx_desc *tx_desc;

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

        INIT_LIST_HEAD(&tx_desc->descriptors);
        tx_desc->status = PREPARED;

        return tx_desc;
}

/**
 * xilinx_dpdma_chan_free_tx_desc - Free a transaction descriptor
 * @chan: DPDMA channel
 * @tx_desc: tx descriptor
 *
 * Free the tx descriptor @tx_desc including its software descriptors.
 */
static void
xilinx_dpdma_chan_free_tx_desc(struct xilinx_dpdma_chan *chan,
                               struct xilinx_dpdma_tx_desc *tx_desc)
{
        struct xilinx_dpdma_sw_desc *sw_desc, *next;

        if (!tx_desc)
                return;

        list_for_each_entry_safe(sw_desc, next, &tx_desc->descriptors, node) {
                list_del(&sw_desc->node);
                xilinx_dpdma_chan_free_sw_desc(chan, sw_desc);
        }

        kfree(tx_desc);
}

/**
 * xilinx_dpdma_chan_submit_tx_desc - Submit a transaction descriptor
 * @chan: DPDMA channel
 * @tx_desc: tx descriptor
 *
 * Submit the tx descriptor @tx_desc to the channel @chan.
 *
 * Return: a cookie assigned to the tx descriptor
 */
static dma_cookie_t
xilinx_dpdma_chan_submit_tx_desc(struct xilinx_dpdma_chan *chan,
                                 struct xilinx_dpdma_tx_desc *tx_desc)
{
        struct xilinx_dpdma_sw_desc *sw_desc;
        dma_cookie_t cookie;
        unsigned long flags;

        spin_lock_irqsave(&chan->lock, flags);

        if (chan->submitted_desc) {
                cookie = chan->submitted_desc->async_tx.cookie;
                goto out_unlock;
        }

        cookie = dma_cookie_assign(&tx_desc->async_tx);

        /* Assign the cookie to descriptors in this transaction */
        /* Only 16 bit will be used, but it should be enough */
        list_for_each_entry(sw_desc, &tx_desc->descriptors, node)
                sw_desc->hw.desc_id = cookie;

        if (tx_desc != chan->allocated_desc)
                dev_err(chan->xdev->dev, "desc != allocated_desc\n");
        else
                chan->allocated_desc = NULL;
        chan->submitted_desc = tx_desc;

        if (chan->id == VIDEO1 || chan->id == VIDEO2) {
                chan->video_group = true;
                chan->xdev->chan[VIDEO0]->video_group = true;
        }

out_unlock:
        spin_unlock_irqrestore(&chan->lock, flags);

        return cookie;
}

/**
 * xilinx_dpdma_chan_free_desc_list - Free a descriptor list
 * @chan: DPDMA channel
 * @list: tx descriptor list
 *
 * Free tx descriptors in the list @list.
 */
static void xilinx_dpdma_chan_free_desc_list(struct xilinx_dpdma_chan *chan,
                                             struct list_head *list)
{
        struct xilinx_dpdma_tx_desc *tx_desc, *next;

        list_for_each_entry_safe(tx_desc, next, list, node) {
                list_del(&tx_desc->node);
                xilinx_dpdma_chan_free_tx_desc(chan, tx_desc);
        }
}

/**
 * xilinx_dpdma_chan_free_all_desc - Free all descriptors of the channel
 * @chan: DPDMA channel
 *
 * Free all descriptors associated with the channel. The channel should be
 * disabled before this function is called, otherwise, this function may
 * result in misbehavior of the system due to remaining outstanding
 * transactions.
 */
static void xilinx_dpdma_chan_free_all_desc(struct xilinx_dpdma_chan *chan)
{
        unsigned long flags;

        spin_lock_irqsave(&chan->lock, flags);

        dev_dbg(chan->xdev->dev, "chan->status = %s\n",
                chan->status == STREAMING ? "STREAMING" : "IDLE");

        xilinx_dpdma_chan_free_tx_desc(chan, chan->allocated_desc);
        chan->allocated_desc = NULL;
        xilinx_dpdma_chan_free_tx_desc(chan, chan->submitted_desc);
        chan->submitted_desc = NULL;
        xilinx_dpdma_chan_free_tx_desc(chan, chan->pending_desc);
        chan->pending_desc = NULL;
        xilinx_dpdma_chan_free_tx_desc(chan, chan->active_desc);
        chan->active_desc = NULL;
        xilinx_dpdma_chan_free_desc_list(chan, &chan->done_list);

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

/**
 * xilinx_dpdma_chan_cleanup_desc - Clean up descriptors
 * @chan: DPDMA channel
 *
 * Trigger the complete callbacks of descriptors with finished transactions.
 * Free descriptors which are no longer in use.
 */
static void xilinx_dpdma_chan_cleanup_desc(struct xilinx_dpdma_chan *chan)
{
        struct xilinx_dpdma_tx_desc *desc;
        dma_async_tx_callback callback;
        void *callback_param;
        unsigned long flags;
        unsigned int cnt, i;

        spin_lock_irqsave(&chan->lock, flags);

        while (!list_empty(&chan->done_list)) {
                desc = list_first_entry(&chan->done_list,
                                        struct xilinx_dpdma_tx_desc, node);
                list_del(&desc->node);

                cnt = desc->done_cnt;
                desc->done_cnt = 0;
                callback = desc->async_tx.callback;
                callback_param = desc->async_tx.callback_param;
                if (callback) {
                        spin_unlock_irqrestore(&chan->lock, flags);
                        for (i = 0; i < cnt; i++)
                                callback(callback_param);
                        spin_lock_irqsave(&chan->lock, flags);
                }

                xilinx_dpdma_chan_free_tx_desc(chan, desc);
        }

        if (chan->active_desc) {
                cnt = chan->active_desc->done_cnt;
                chan->active_desc->done_cnt = 0;
                callback = chan->active_desc->async_tx.callback;
                callback_param = chan->active_desc->async_tx.callback_param;
                if (callback) {
                        spin_unlock_irqrestore(&chan->lock, flags);
                        for (i = 0; i < cnt; i++)
                                callback(callback_param);
                        spin_lock_irqsave(&chan->lock, flags);
                }
        }

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

/**
 * xilinx_dpdma_chan_desc_active - Set the descriptor as active
 * @chan: DPDMA channel
 *
 * Make the pending descriptor @chan->pending_desc as active. This function
 * should be called when the channel starts operating on the pending descriptor.
 */
static void xilinx_dpdma_chan_desc_active(struct xilinx_dpdma_chan *chan)
{
        unsigned long flags;

        spin_lock_irqsave(&chan->lock, flags);

        if (!chan->pending_desc)
                goto out_unlock;

        if (chan->active_desc)
                list_add_tail(&chan->active_desc->node, &chan->done_list);

        chan->active_desc = chan->pending_desc;
        chan->pending_desc = NULL;

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

/**
 * xilinx_dpdma_chan_desc_done_intr - Mark the current descriptor as 'done'
 * @chan: DPDMA channel
 *
 * Mark the current active descriptor @chan->active_desc as 'done'. This
 * function should be called to mark completion of the currently active
 * descriptor.
 */
static void xilinx_dpdma_chan_desc_done_intr(struct xilinx_dpdma_chan *chan)
{
        unsigned long flags;

        spin_lock_irqsave(&chan->lock, flags);

        if (!chan->active_desc) {
                dev_dbg(chan->xdev->dev, "done intr with no active desc\n");
                goto out_unlock;
        }

        chan->active_desc->done_cnt++;
        if (chan->active_desc->status ==  PREPARED) {
                dma_cookie_complete(&chan->active_desc->async_tx);
                chan->active_desc->status = ACTIVE;
        }

out_unlock:
        spin_unlock_irqrestore(&chan->lock, flags);
        tasklet_schedule(&chan->done_task);
}

/**
 * xilinx_dpdma_chan_prep_slave_sg - Prepare a scatter-gather dma descriptor
 * @chan: DPDMA channel
 * @sgl: scatter-gather list
 *
 * Prepare a tx descriptor incudling internal software/hardware descriptors
 * for the given scatter-gather transaction.
 *
 * Return: A dma async tx descriptor on success, or NULL.
 */
static struct dma_async_tx_descriptor *
xilinx_dpdma_chan_prep_slave_sg(struct xilinx_dpdma_chan *chan,
                                struct scatterlist *sgl)
{
        struct xilinx_dpdma_tx_desc *tx_desc;
        struct xilinx_dpdma_sw_desc *sw_desc, *last = NULL;
        struct scatterlist *iter = sgl;
        u32 line_size = 0;

        if (chan->allocated_desc)
                return &chan->allocated_desc->async_tx;

        tx_desc = xilinx_dpdma_chan_alloc_tx_desc(chan);
        if (!tx_desc)
                return NULL;

        while (!sg_is_chain(iter))
                line_size += sg_dma_len(iter++);

        while (sgl) {
                struct xilinx_dpdma_hw_desc *hw_desc;
                dma_addr_t dma_addr[4];
                unsigned int num_pages = 0;

                sw_desc = xilinx_dpdma_chan_alloc_sw_desc(chan);
                if (!sw_desc)
                        goto error;

                while (!sg_is_chain(sgl) && !sg_is_last(sgl)) {
                        dma_addr[num_pages] = sg_dma_address(sgl++);
                        if (!IS_ALIGNED(dma_addr[num_pages++],
                                        XILINX_DPDMA_ALIGN_BYTES)) {
                                dev_err(chan->xdev->dev,
                                        "buffer should be aligned at %d B\n",
                                        XILINX_DPDMA_ALIGN_BYTES);
                                goto error;
                        }
                }

                chan->xdev->desc_addr(sw_desc, last, dma_addr, num_pages);
                hw_desc = &sw_desc->hw;
                hw_desc->xfer_size = line_size;
                hw_desc->hsize_stride =
                        line_size << XILINX_DPDMA_DESC_HSIZE_STRIDE_HSIZE_SHIFT;
                hw_desc->control |= XILINX_DPDMA_DESC_CONTROL_PREEMBLE;
                hw_desc->control |= XILINX_DPDMA_DESC_CONTROL_FRAG_MODE;
                hw_desc->control |= XILINX_DPDMA_DESC_CONTROL_IGNORE_DONE;

                list_add_tail(&sw_desc->node, &tx_desc->descriptors);
                last = sw_desc;
                if (sg_is_last(sgl))
                        break;
                sgl = sg_chain_ptr(sgl);
        }

        sw_desc = list_first_entry(&tx_desc->descriptors,
                                   struct xilinx_dpdma_sw_desc, node);
        if (chan->xdev->ext_addr)
                xilinx_dpdma_sw_desc_next_64(last, sw_desc);
        else
                xilinx_dpdma_sw_desc_next_32(last, sw_desc);
        last->hw.control |= XILINX_DPDMA_DESC_CONTROL_COMPLETE_INTR;
        last->hw.control |= XILINX_DPDMA_DESC_CONTROL_LAST_OF_FRAME;

        chan->allocated_desc = tx_desc;

        return &tx_desc->async_tx;

error:
        xilinx_dpdma_chan_free_tx_desc(chan, tx_desc);

        return NULL;
}

/**
 * xilinx_dpdma_chan_prep_cyclic - Prepare a cyclic dma descriptor
 * @chan: DPDMA channel
 * @buf_addr: buffer address
 * @buf_len: buffer length
 * @period_len: number of periods
 *
 * Prepare a tx descriptor incudling internal software/hardware descriptors
 * for the given cyclic transaction.
 *
 * Return: A dma async tx descriptor on success, or NULL.
 */
static struct dma_async_tx_descriptor *
xilinx_dpdma_chan_prep_cyclic(struct xilinx_dpdma_chan *chan,
                              dma_addr_t buf_addr, size_t buf_len,
                              size_t period_len)
{
        struct xilinx_dpdma_tx_desc *tx_desc;
        struct xilinx_dpdma_sw_desc *sw_desc, *last = NULL;
        unsigned int periods = buf_len / period_len;
        unsigned int i;

        if (chan->allocated_desc)
                return &chan->allocated_desc->async_tx;

        tx_desc = xilinx_dpdma_chan_alloc_tx_desc(chan);
        if (!tx_desc)
                return NULL;

        for (i = 0; i < periods; i++) {
                struct xilinx_dpdma_hw_desc *hw_desc;

                if (!IS_ALIGNED(buf_addr, XILINX_DPDMA_ALIGN_BYTES)) {
                        dev_err(chan->xdev->dev,
                                "buffer should be aligned at %d B\n",
                                XILINX_DPDMA_ALIGN_BYTES);
                        goto error;
                }

                sw_desc = xilinx_dpdma_chan_alloc_sw_desc(chan);
                if (!sw_desc)
                        goto error;

                chan->xdev->desc_addr(sw_desc, last, &buf_addr, 1);
                hw_desc = &sw_desc->hw;
                hw_desc->xfer_size = period_len;
                hw_desc->hsize_stride =
                        period_len <<
                        XILINX_DPDMA_DESC_HSIZE_STRIDE_HSIZE_SHIFT;
                hw_desc->hsize_stride |=
                        period_len <<
                        XILINX_DPDMA_DESC_HSIZE_STRIDE_STRIDE_SHIFT;
                hw_desc->control |= XILINX_DPDMA_DESC_CONTROL_PREEMBLE;
                hw_desc->control |= XILINX_DPDMA_DESC_CONTROL_IGNORE_DONE;
                hw_desc->control |= XILINX_DPDMA_DESC_CONTROL_COMPLETE_INTR;

                list_add_tail(&sw_desc->node, &tx_desc->descriptors);

                buf_addr += period_len;
                last = sw_desc;
        }

        sw_desc = list_first_entry(&tx_desc->descriptors,
                                   struct xilinx_dpdma_sw_desc, node);
        if (chan->xdev->ext_addr)
                xilinx_dpdma_sw_desc_next_64(last, sw_desc);
        else
                xilinx_dpdma_sw_desc_next_32(last, sw_desc);
        last->hw.control |= XILINX_DPDMA_DESC_CONTROL_LAST_OF_FRAME;

        chan->allocated_desc = tx_desc;

        return &tx_desc->async_tx;

error:
        xilinx_dpdma_chan_free_tx_desc(chan, tx_desc);

        return NULL;
}

/**
 * xilinx_dpdma_chan_prep_interleaved - Prepare a interleaved dma descriptor
 * @chan: DPDMA channel
 * @xt: dma interleaved template
 *
 * Prepare a tx descriptor incudling internal software/hardware descriptors
 * based on @xt.
 *
 * Return: A dma async tx descriptor on success, or NULL.
 */
static struct dma_async_tx_descriptor *
xilinx_dpdma_chan_prep_interleaved(struct xilinx_dpdma_chan *chan,
                                   struct dma_interleaved_template *xt)
{
        struct xilinx_dpdma_tx_desc *tx_desc;
        struct xilinx_dpdma_sw_desc *sw_desc;
        struct xilinx_dpdma_hw_desc *hw_desc;
        size_t hsize = xt->sgl[0].size;
        size_t stride = hsize + xt->sgl[0].icg;

        if (!IS_ALIGNED(xt->src_start, XILINX_DPDMA_ALIGN_BYTES)) {
                dev_err(chan->xdev->dev, "buffer should be aligned at %d B\n",
                        XILINX_DPDMA_ALIGN_BYTES);
                return NULL;
        }

        if (chan->allocated_desc)
                return &chan->allocated_desc->async_tx;

        tx_desc = xilinx_dpdma_chan_alloc_tx_desc(chan);
        if (!tx_desc)
                return NULL;

        sw_desc = xilinx_dpdma_chan_alloc_sw_desc(chan);
        if (!sw_desc)
                goto error;

        chan->xdev->desc_addr(sw_desc, sw_desc, &xt->src_start, 1);
        hw_desc = &sw_desc->hw;
        hw_desc->xfer_size = hsize * xt->numf;
        hw_desc->hsize_stride = hsize <<
                                XILINX_DPDMA_DESC_HSIZE_STRIDE_HSIZE_SHIFT;
        hw_desc->hsize_stride |= (stride / 16) <<
                                 XILINX_DPDMA_DESC_HSIZE_STRIDE_STRIDE_SHIFT;
        hw_desc->control |= XILINX_DPDMA_DESC_CONTROL_PREEMBLE;
        hw_desc->control |= XILINX_DPDMA_DESC_CONTROL_COMPLETE_INTR;
        hw_desc->control |= XILINX_DPDMA_DESC_CONTROL_IGNORE_DONE;
        hw_desc->control |= XILINX_DPDMA_DESC_CONTROL_LAST_OF_FRAME;

        list_add_tail(&sw_desc->node, &tx_desc->descriptors);
        chan->allocated_desc = tx_desc;

        return &tx_desc->async_tx;

error:
        xilinx_dpdma_chan_free_tx_desc(chan, tx_desc);

        return NULL;
}

/* Xilinx DPDMA channel operations */

/**
 * xilinx_dpdma_chan_enable - Enable the channel
 * @chan: DPDMA channel
 *
 * Enable the channel and its interrupts. Set the QoS values for video class.
 */
static inline void xilinx_dpdma_chan_enable(struct xilinx_dpdma_chan *chan)
{
        u32 reg;

        reg = XILINX_DPDMA_INTR_CHAN_MASK << chan->id;
        reg |= XILINX_DPDMA_INTR_GLOBAL_MASK;
        dpdma_set(chan->xdev->reg, XILINX_DPDMA_IEN, reg);
        reg = XILINX_DPDMA_EINTR_CHAN_ERR_MASK << chan->id;
        reg |= XILINX_DPDMA_INTR_GLOBAL_ERR;
        dpdma_set(chan->xdev->reg, XILINX_DPDMA_EIEN, reg);

        reg = XILINX_DPDMA_CH_CNTL_ENABLE;
        reg |= XILINX_DPDMA_CH_CNTL_QOS_VID_CLASS <<
               XILINX_DPDMA_CH_CNTL_QOS_DSCR_WR_SHIFT;
        reg |= XILINX_DPDMA_CH_CNTL_QOS_VID_CLASS <<
               XILINX_DPDMA_CH_CNTL_QOS_DSCR_RD_SHIFT;
        reg |= XILINX_DPDMA_CH_CNTL_QOS_VID_CLASS <<
               XILINX_DPDMA_CH_CNTL_QOS_DATA_RD_SHIFT;
        dpdma_set(chan->reg, XILINX_DPDMA_CH_CNTL, reg);
}

/**
 * xilinx_dpdma_chan_disable - Disable the channel
 * @chan: DPDMA channel
 *
 * Disable the channel and its interrupts.
 */
static inline void xilinx_dpdma_chan_disable(struct xilinx_dpdma_chan *chan)
{
        u32 reg;

        reg = XILINX_DPDMA_INTR_CHAN_MASK << chan->id;
        dpdma_clr(chan->xdev->reg, XILINX_DPDMA_IEN, reg);
        reg = XILINX_DPDMA_EINTR_CHAN_ERR_MASK << chan->id;
        dpdma_clr(chan->xdev->reg, XILINX_DPDMA_EIEN, reg);

        dpdma_clr(chan->reg, XILINX_DPDMA_CH_CNTL, XILINX_DPDMA_CH_CNTL_ENABLE);
}

/**
 * xilinx_dpdma_chan_pause - Pause the channel
 * @chan: DPDMA channel
 *
 * Pause the channel.
 */
static inline void xilinx_dpdma_chan_pause(struct xilinx_dpdma_chan *chan)
{
        dpdma_set(chan->reg, XILINX_DPDMA_CH_CNTL, XILINX_DPDMA_CH_CNTL_PAUSE);
}

/**
 * xilinx_dpdma_chan_unpause - Unpause the channel
 * @chan: DPDMA channel
 *
 * Unpause the channel.
 */
static inline void xilinx_dpdma_chan_unpause(struct xilinx_dpdma_chan *chan)
{
        dpdma_clr(chan->reg, XILINX_DPDMA_CH_CNTL, XILINX_DPDMA_CH_CNTL_PAUSE);
}

static u32
xilinx_dpdma_chan_video_group_ready(struct xilinx_dpdma_chan *chan)
{
        struct xilinx_dpdma_device *xdev = chan->xdev;
        u32 i = 0, ret = 0;

        for (i = VIDEO0; i < GRAPHICS; i++) {
                if (xdev->chan[i]->video_group &&
                    xdev->chan[i]->status != STREAMING)
                        return 0;

                if (xdev->chan[i]->video_group)
                        ret |= BIT(i);
        }

        return ret;
}

/**
 * xilinx_dpdma_chan_issue_pending - Issue the pending descriptor
 * @chan: DPDMA channel
 *
 * Issue the first pending descriptor from @chan->submitted_desc. If the channel
 * is already streaming, the channel is re-triggered with the pending
 * descriptor.
 */
static void xilinx_dpdma_chan_issue_pending(struct xilinx_dpdma_chan *chan)
{
        struct xilinx_dpdma_device *xdev = chan->xdev;
        struct xilinx_dpdma_sw_desc *sw_desc;
        unsigned long flags;
        u32 reg, channels;

        spin_lock_irqsave(&chan->lock, flags);

        if (!chan->submitted_desc || chan->pending_desc)
                goto out_unlock;

        chan->pending_desc = chan->submitted_desc;
        chan->submitted_desc = NULL;

        sw_desc = list_first_entry(&chan->pending_desc->descriptors,
                                   struct xilinx_dpdma_sw_desc, node);
        dpdma_write(chan->reg, XILINX_DPDMA_CH_DESC_START_ADDR,
                    (u32)sw_desc->phys);
        if (xdev->ext_addr)
                dpdma_write(chan->reg, XILINX_DPDMA_CH_DESC_START_ADDRE,
                            ((u64)sw_desc->phys >> 32) &
                            XILINX_DPDMA_DESC_ADDR_EXT_ADDR_MASK);

        if (chan->first_frame) {
                chan->first_frame = false;
                if (chan->video_group) {
                        channels = xilinx_dpdma_chan_video_group_ready(chan);
                        if (!channels)
                                goto out_unlock;
                        reg = channels << XILINX_DPDMA_GBL_TRIG_SHIFT;
                } else {
                        reg = 1 << (XILINX_DPDMA_GBL_TRIG_SHIFT + chan->id);
                }
        } else {
                if (chan->video_group) {
                        channels = xilinx_dpdma_chan_video_group_ready(chan);
                        if (!channels)
                                goto out_unlock;
                        reg = channels << XILINX_DPDMA_GBL_RETRIG_SHIFT;
                } else {
                        reg = 1 << (XILINX_DPDMA_GBL_RETRIG_SHIFT + chan->id);
                }
        }

        dpdma_write(xdev->reg, XILINX_DPDMA_GBL, reg);

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

/**
 * xilinx_dpdma_chan_start - Start the channel
 * @chan: DPDMA channel
 *
 * Start the channel by enabling interrupts and triggering the channel.
 * If the channel is enabled already or there's no pending descriptor, this
 * function won't do anything on the channel.
 */
static void xilinx_dpdma_chan_start(struct xilinx_dpdma_chan *chan)
{
        unsigned long flags;

        spin_lock_irqsave(&chan->lock, flags);

        if (!chan->submitted_desc || chan->status == STREAMING)
                goto out_unlock;

        xilinx_dpdma_chan_unpause(chan);
        xilinx_dpdma_chan_enable(chan);
        chan->first_frame = true;
        chan->status = STREAMING;

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

/**
 * xilinx_dpdma_chan_ostand - Number of outstanding transactions
 * @chan: DPDMA channel
 *
 * Read and return the number of outstanding transactions from register.
 *
 * Return: Number of outstanding transactions from the status register.
 */
static inline u32 xilinx_dpdma_chan_ostand(struct xilinx_dpdma_chan *chan)
{
        return dpdma_read(chan->reg, XILINX_DPDMA_CH_STATUS) >>
               XILINX_DPDMA_CH_STATUS_OTRAN_CNT_SHIFT &
               XILINX_DPDMA_CH_STATUS_OTRAN_CNT_MASK;
}

/**
 * xilinx_dpdma_chan_no_ostand - Notify no outstanding transaction event
 * @chan: DPDMA channel
 *
 * Notify waiters for no outstanding event, so waiters can stop the channel
 * safely. This function is supposed to be called when 'no oustanding' interrupt
 * is generated. The 'no outstanding' interrupt is disabled and should be
 * re-enabled when this event is handled. If the channel status register still
 * shows some number of outstanding transactions, the interrupt remains enabled.
 *
 * Return: 0 on success. On failure, -EWOULDBLOCK if there's still outstanding
 * transaction(s).
 */
static int xilinx_dpdma_chan_notify_no_ostand(struct xilinx_dpdma_chan *chan)
{
        u32 cnt;

        cnt = xilinx_dpdma_chan_ostand(chan);
        if (cnt) {
                dev_dbg(chan->xdev->dev, "%d outstanding transactions\n", cnt);
                return -EWOULDBLOCK;
        }

        /* Disable 'no oustanding' interrupt */
        dpdma_write(chan->xdev->reg, XILINX_DPDMA_IDS,
                    1 << (XILINX_DPDMA_INTR_NO_OSTAND_SHIFT + chan->id));
        wake_up(&chan->wait_to_stop);

        return 0;
}

/**
 * xilinx_dpdma_chan_wait_no_ostand - Wait for the oustanding transaction intr
 * @chan: DPDMA channel
 *
 * Wait for the no outstanding transaction interrupt. This functions can sleep
 * for 50ms.
 *
 * Return: 0 on success. On failure, -ETIMEOUT for time out, or the error code
 * from wait_event_interruptible_timeout().
 */
static int xilinx_dpdma_chan_wait_no_ostand(struct xilinx_dpdma_chan *chan)
{
        int ret;

        /* Wait for a no outstanding transaction interrupt upto 50msec */
        ret = wait_event_interruptible_timeout(chan->wait_to_stop,
                                               !xilinx_dpdma_chan_ostand(chan),
                                               msecs_to_jiffies(50));
        if (ret > 0) {
                dpdma_write(chan->xdev->reg, XILINX_DPDMA_IEN,
                            1 <<
                            (XILINX_DPDMA_INTR_NO_OSTAND_SHIFT + chan->id));
                return 0;
        }

        dev_err(chan->xdev->dev, "not ready to stop: %d trans\n",
                xilinx_dpdma_chan_ostand(chan));

        if (ret == 0)
                return -ETIMEDOUT;

        return ret;
}

/**
 * xilinx_dpdma_chan_poll_no_ostand - Poll the oustanding transaction status reg
 * @chan: DPDMA channel
 *
 * Poll the outstanding transaction status, and return when there's no
 * outstanding transaction. This functions can be used in the interrupt context
 * or where the atomicity is required. Calling thread may wait more than 50ms.
 *
 * Return: 0 on success, or -ETIMEDOUT.
 */
static int xilinx_dpdma_chan_poll_no_ostand(struct xilinx_dpdma_chan *chan)
{
        u32 cnt, loop = 50000;

        /* Poll at least for 50ms (20 fps). */
        do {
                cnt = xilinx_dpdma_chan_ostand(chan);
                udelay(1);
        } while (loop-- > 0 && cnt);

        if (loop) {
                dpdma_write(chan->xdev->reg, XILINX_DPDMA_IEN,
                            1 <<
                            (XILINX_DPDMA_INTR_NO_OSTAND_SHIFT + chan->id));
                return 0;
        }

        dev_err(chan->xdev->dev, "not ready to stop: %d trans\n",
                xilinx_dpdma_chan_ostand(chan));

        return -ETIMEDOUT;
}

/**
 * xilinx_dpdma_chan_stop - Stop the channel
 * @chan: DPDMA channel
 *
 * Stop the channel with the following sequence: 1. Pause, 2. Wait (sleep) for
 * no outstanding transaction interrupt, 3. Disable the channel.
 *
 * Return: 0 on success, or error code from xilinx_dpdma_chan_wait_no_ostand().
 */
static int xilinx_dpdma_chan_stop(struct xilinx_dpdma_chan *chan)
{
        unsigned long flags;
        bool ret;

        xilinx_dpdma_chan_pause(chan);
        ret = xilinx_dpdma_chan_wait_no_ostand(chan);
        if (ret)
                return ret;

        spin_lock_irqsave(&chan->lock, flags);
        xilinx_dpdma_chan_disable(chan);
        chan->status = IDLE;
        spin_unlock_irqrestore(&chan->lock, flags);

        return 0;
}

/**
 * xilinx_dpdma_chan_alloc_resources - Allocate resources for the channel
 * @chan: DPDMA channel
 *
 * Allocate a descriptor pool for the channel.
 *
 * Return: 0 on success, or -ENOMEM if failed to allocate a pool.
 */
static int xilinx_dpdma_chan_alloc_resources(struct xilinx_dpdma_chan *chan)
{
        chan->desc_pool = dma_pool_create(dev_name(chan->xdev->dev),
                                chan->xdev->dev,
                                sizeof(struct xilinx_dpdma_sw_desc),
                                __alignof__(struct xilinx_dpdma_sw_desc), 0);
        if (!chan->desc_pool) {
                dev_err(chan->xdev->dev,
                        "failed to allocate a descriptor pool\n");
                return -ENOMEM;
        }

        return 0;
}

/**
 * xilinx_dpdma_chan_free_resources - Free all resources for the channel
 * @chan: DPDMA channel
 *
 * Free all descriptors and the descriptor pool for the channel.
 */
static void xilinx_dpdma_chan_free_resources(struct xilinx_dpdma_chan *chan)
{
        xilinx_dpdma_chan_free_all_desc(chan);
        dma_pool_destroy(chan->desc_pool);
        chan->desc_pool = NULL;
}

/**
 * xilinx_dpdma_chan_terminate_all - Terminate the channel and descriptors
 * @chan: DPDMA channel
 *
 * Stop the channel and free all associated descriptors.
 *
 * Return: 0 on success, or the error code from xilinx_dpdma_chan_stop().
 */
static int xilinx_dpdma_chan_terminate_all(struct xilinx_dpdma_chan *chan)
{
        struct xilinx_dpdma_device *xdev = chan->xdev;
        int ret;
        unsigned int i;

        if (chan->video_group) {
                for (i = VIDEO0; i < GRAPHICS; i++) {
                        if (xdev->chan[i]->video_group &&
                            xdev->chan[i]->status == STREAMING) {
                                xilinx_dpdma_chan_pause(xdev->chan[i]);
                                xdev->chan[i]->video_group = false;
                        }
                }
        }

        ret = xilinx_dpdma_chan_stop(chan);
        if (ret)
                return ret;

        xilinx_dpdma_chan_free_all_desc(chan);

        return 0;
}

/**
 * xilinx_dpdma_chan_err - Detect any channel error
 * @chan: DPDMA channel
 * @isr: masked Interrupt Status Register
 * @eisr: Error Interrupt Status Register
 *
 * Return: true if any channel error occurs, or false otherwise.
 */
static bool
xilinx_dpdma_chan_err(struct xilinx_dpdma_chan *chan, u32 isr, u32 eisr)
{

        if (!chan)
                return false;

        if (chan->status == STREAMING &&
            ((isr & (XILINX_DPDMA_INTR_CHAN_ERR_MASK << chan->id)) ||
            (eisr & (XILINX_DPDMA_EINTR_CHAN_ERR_MASK << chan->id))))
                return true;

        return false;
}

/**
 * xilinx_dpdma_chan_handle_err - DPDMA channel error handling
 * @chan: DPDMA channel
 *
 * This function is called when any channel error or any global error occurs.
 * The function disables the paused channel by errors and determines
 * if the current active descriptor can be rescheduled depending on
 * the descriptor status.
 */
static void xilinx_dpdma_chan_handle_err(struct xilinx_dpdma_chan *chan)
{
        struct xilinx_dpdma_device *xdev = chan->xdev;
        struct device *dev = xdev->dev;
        unsigned long flags;

        spin_lock_irqsave(&chan->lock, flags);

        dev_dbg(dev, "cur desc addr = 0x%04x%08x\n",
                dpdma_read(chan->reg, XILINX_DPDMA_CH_DESC_START_ADDRE),
                dpdma_read(chan->reg, XILINX_DPDMA_CH_DESC_START_ADDR));
        dev_dbg(dev, "cur payload addr = 0x%04x%08x\n",
                dpdma_read(chan->reg, XILINX_DPDMA_CH_PYLD_CUR_ADDRE),
                dpdma_read(chan->reg, XILINX_DPDMA_CH_PYLD_CUR_ADDR));

        xilinx_dpdma_chan_disable(chan);
        chan->status = IDLE;

        /* Decide if the current descriptor can be rescheduled */
        if (chan->active_desc) {
                switch (chan->active_desc->status) {
                case ACTIVE:
                case PREPARED:
                        xilinx_dpdma_chan_free_tx_desc(chan,
                                                       chan->submitted_desc);
                        chan->submitted_desc = NULL;
                        xilinx_dpdma_chan_free_tx_desc(chan,
                                                       chan->pending_desc);
                        chan->pending_desc = NULL;
                        chan->active_desc->status = ERRORED;
                        chan->submitted_desc = chan->active_desc;
                        break;
                case ERRORED:
                        dev_err(dev, "desc is dropped by unrecoverable err\n");
                        xilinx_dpdma_chan_dump_tx_desc(chan, chan->active_desc);
                        xilinx_dpdma_chan_free_tx_desc(chan, chan->active_desc);
                        break;
                default:
                        break;
                }
                chan->active_desc = NULL;
        }

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

/* DMA tx descriptor */

static dma_cookie_t xilinx_dpdma_tx_submit(struct dma_async_tx_descriptor *tx)
{
        struct xilinx_dpdma_chan *chan = to_xilinx_chan(tx->chan);
        struct xilinx_dpdma_tx_desc *tx_desc = to_dpdma_tx_desc(tx);

        return xilinx_dpdma_chan_submit_tx_desc(chan, tx_desc);
}

/* DMA channel operations */

static struct dma_async_tx_descriptor *
xilinx_dpdma_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_dpdma_chan *chan = to_xilinx_chan(dchan);
        struct dma_async_tx_descriptor *async_tx;

        if (direction != DMA_MEM_TO_DEV)
                return NULL;

        if (!sgl || sg_len < 2)
                return NULL;

        async_tx = xilinx_dpdma_chan_prep_slave_sg(chan, sgl);
        if (!async_tx)
                return NULL;

        dma_async_tx_descriptor_init(async_tx, dchan);
        async_tx->tx_submit = xilinx_dpdma_tx_submit;
        async_tx->flags = flags;
        async_tx_ack(async_tx);

        return async_tx;
}

static struct dma_async_tx_descriptor *
xilinx_dpdma_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_dpdma_chan *chan = to_xilinx_chan(dchan);
        struct dma_async_tx_descriptor *async_tx;

        if (direction != DMA_MEM_TO_DEV)
                return NULL;

        if (buf_len % period_len)
                return NULL;

        async_tx = xilinx_dpdma_chan_prep_cyclic(chan, buf_addr, buf_len,
                                                 period_len);
        if (!async_tx)
                return NULL;

        dma_async_tx_descriptor_init(async_tx, dchan);
        async_tx->tx_submit = xilinx_dpdma_tx_submit;
        async_tx->flags = flags;
        async_tx_ack(async_tx);

        return async_tx;
}

static struct dma_async_tx_descriptor *
xilinx_dpdma_prep_interleaved_dma(struct dma_chan *dchan,
                                  struct dma_interleaved_template *xt,
                                  unsigned long flags)
{
        struct xilinx_dpdma_chan *chan = to_xilinx_chan(dchan);
        struct dma_async_tx_descriptor *async_tx;

        if (xt->dir != DMA_MEM_TO_DEV)
                return NULL;

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

        async_tx = xilinx_dpdma_chan_prep_interleaved(chan, xt);
        if (!async_tx)
                return NULL;

        dma_async_tx_descriptor_init(async_tx, dchan);
        async_tx->tx_submit = xilinx_dpdma_tx_submit;
        async_tx->flags = flags;
        async_tx_ack(async_tx);

        return async_tx;
}

static int xilinx_dpdma_alloc_chan_resources(struct dma_chan *dchan)
{
        struct xilinx_dpdma_chan *chan = to_xilinx_chan(dchan);

        dma_cookie_init(dchan);

        return xilinx_dpdma_chan_alloc_resources(chan);
}

static void xilinx_dpdma_free_chan_resources(struct dma_chan *dchan)
{
        struct xilinx_dpdma_chan *chan = to_xilinx_chan(dchan);

        xilinx_dpdma_chan_free_resources(chan);
}

static enum dma_status xilinx_dpdma_tx_status(struct dma_chan *dchan,
                                              dma_cookie_t cookie,
                                              struct dma_tx_state *txstate)
{
        return dma_cookie_status(dchan, cookie, txstate);
}

static void xilinx_dpdma_issue_pending(struct dma_chan *dchan)
{
        struct xilinx_dpdma_chan *chan = to_xilinx_chan(dchan);

        xilinx_dpdma_chan_start(chan);
        xilinx_dpdma_chan_issue_pending(chan);
}

static int xilinx_dpdma_config(struct dma_chan *dchan,
                               struct dma_slave_config *config)
{
        if (config->direction != DMA_MEM_TO_DEV)
                return -EINVAL;

        return 0;
}

static int xilinx_dpdma_pause(struct dma_chan *dchan)
{
        xilinx_dpdma_chan_pause(to_xilinx_chan(dchan));

        return 0;
}

static int xilinx_dpdma_resume(struct dma_chan *dchan)
{
        xilinx_dpdma_chan_unpause(to_xilinx_chan(dchan));

        return 0;
}

static int xilinx_dpdma_terminate_all(struct dma_chan *dchan)
{
        return xilinx_dpdma_chan_terminate_all(to_xilinx_chan(dchan));
}

/* Xilinx DPDMA device operations */

/**
 * xilinx_dpdma_err - Detect any global error
 * @isr: Interrupt Status Register
 * @eisr: Error Interrupt Status Register
 *
 * Return: True if any global error occurs, or false otherwise.
 */
static bool xilinx_dpdma_err(u32 isr, u32 eisr)
{
        if ((isr & XILINX_DPDMA_INTR_GLOBAL_ERR ||
            eisr & XILINX_DPDMA_EINTR_GLOBAL_ERR))
                return true;

        return false;
}

/**
 * xilinx_dpdma_handle_err_intr - Handle DPDMA error interrupt
 * @xdev: DPDMA device
 * @isr: masked Interrupt Status Register
 * @eisr: Error Interrupt Status Register
 *
 * Handle if any error occurs based on @isr and @eisr. This function disables
 * corresponding error interrupts, and those should be re-enabled once handling
 * is done.
 */
static void xilinx_dpdma_handle_err_intr(struct xilinx_dpdma_device *xdev,
                                         u32 isr, u32 eisr)
{
        bool err = xilinx_dpdma_err(isr, eisr);
        unsigned int i;

        dev_err(xdev->dev, "error intr: isr = 0x%08x, eisr = 0x%08x\n",
                isr, eisr);

        /* Disable channel error interrupts until errors are handled. */
        dpdma_write(xdev->reg, XILINX_DPDMA_IDS,
                    isr & ~XILINX_DPDMA_INTR_GLOBAL_ERR);
        dpdma_write(xdev->reg, XILINX_DPDMA_EIDS,
                    eisr & ~XILINX_DPDMA_EINTR_GLOBAL_ERR);

        for (i = 0; i < XILINX_DPDMA_NUM_CHAN; i++)
                if (err || xilinx_dpdma_chan_err(xdev->chan[i], isr, eisr))
                        tasklet_schedule(&xdev->chan[i]->err_task);
}

/**
 * xilinx_dpdma_handle_vsync_intr - Handle the VSYNC interrupt
 * @xdev: DPDMA device
 *
 * Handle the VSYNC event. At this point, the current frame becomes active,
 * which means the DPDMA actually starts fetching, and the next frame can be
 * scheduled.
 */
static void xilinx_dpdma_handle_vsync_intr(struct xilinx_dpdma_device *xdev)
{
        unsigned int i;

        for (i = 0; i < XILINX_DPDMA_NUM_CHAN; i++) {
                if (xdev->chan[i] &&
                    xdev->chan[i]->status == STREAMING) {
                        xilinx_dpdma_chan_desc_active(xdev->chan[i]);
                        xilinx_dpdma_chan_issue_pending(xdev->chan[i]);
                }
        }
}

/**
 * xilinx_dpdma_enable_intr - Enable interrupts
 * @xdev: DPDMA device
 *
 * Enable interrupts.
 */
static void xilinx_dpdma_enable_intr(struct xilinx_dpdma_device *xdev)
{
        dpdma_write(xdev->reg, XILINX_DPDMA_IEN, XILINX_DPDMA_INTR_ALL);
        dpdma_write(xdev->reg, XILINX_DPDMA_EIEN, XILINX_DPDMA_EINTR_ALL);
}

/**
 * xilinx_dpdma_disable_intr - Disable interrupts
 * @xdev: DPDMA device
 *
 * Disable interrupts.
 */
static void xilinx_dpdma_disable_intr(struct xilinx_dpdma_device *xdev)
{
        dpdma_write(xdev->reg, XILINX_DPDMA_IDS, XILINX_DPDMA_INTR_ERR_ALL);
        dpdma_write(xdev->reg, XILINX_DPDMA_EIDS, XILINX_DPDMA_EINTR_ALL);
}

/* Interrupt handling operations*/

/**
 * xilinx_dpdma_chan_err_task - Per channel tasklet for error handling
 * @data: tasklet data to be casted to DPDMA channel structure
 *
 * Per channel error handling tasklet. This function waits for the outstanding
 * transaction to complete and triggers error handling. After error handling,
 * re-enable channel error interrupts, and restart the channel if needed.
 */
static void xilinx_dpdma_chan_err_task(unsigned long data)
{
        struct xilinx_dpdma_chan *chan = (struct xilinx_dpdma_chan *)data;
        struct xilinx_dpdma_device *xdev = chan->xdev;

        /* Proceed error handling even when polling fails. */
        xilinx_dpdma_chan_poll_no_ostand(chan);

        xilinx_dpdma_chan_handle_err(chan);

        dpdma_write(xdev->reg, XILINX_DPDMA_IEN,
                    XILINX_DPDMA_INTR_CHAN_ERR_MASK << chan->id);
        dpdma_write(xdev->reg, XILINX_DPDMA_EIEN,
                    XILINX_DPDMA_EINTR_CHAN_ERR_MASK << chan->id);

        xilinx_dpdma_chan_start(chan);
        xilinx_dpdma_chan_issue_pending(chan);
}

/**
 * xilinx_dpdma_chan_done_task - Per channel tasklet for done interrupt handling
 * @data: tasklet data to be casted to DPDMA channel structure
 *
 * Per channel done interrupt handling tasklet.
 */
static void xilinx_dpdma_chan_done_task(unsigned long data)
{
        struct xilinx_dpdma_chan *chan = (struct xilinx_dpdma_chan *)data;

        xilinx_dpdma_chan_cleanup_desc(chan);
}

static irqreturn_t xilinx_dpdma_irq_handler(int irq, void *data)
{
        struct xilinx_dpdma_device *xdev = data;
        u32 status, error, i;
        unsigned long masked;

        status = dpdma_read(xdev->reg, XILINX_DPDMA_ISR);
        error = dpdma_read(xdev->reg, XILINX_DPDMA_EISR);
        if (!status && !error)
                return IRQ_NONE;

        dpdma_write(xdev->reg, XILINX_DPDMA_ISR, status);
        dpdma_write(xdev->reg, XILINX_DPDMA_EISR, error);

        if (status & XILINX_DPDMA_INTR_VSYNC)
                xilinx_dpdma_handle_vsync_intr(xdev);

        masked = (status & XILINX_DPDMA_INTR_DESC_DONE_MASK) >>
                 XILINX_DPDMA_INTR_DESC_DONE_SHIFT;
        if (masked)
                for_each_set_bit(i, &masked, XILINX_DPDMA_NUM_CHAN)
                        xilinx_dpdma_chan_desc_done_intr(xdev->chan[i]);

        masked = (status & XILINX_DPDMA_INTR_NO_OSTAND_MASK) >>
                 XILINX_DPDMA_INTR_NO_OSTAND_SHIFT;
        if (masked)
                for_each_set_bit(i, &masked, XILINX_DPDMA_NUM_CHAN)
                        xilinx_dpdma_chan_notify_no_ostand(xdev->chan[i]);

        masked = status & XILINX_DPDMA_INTR_ERR_ALL;
        if (masked || error)
                xilinx_dpdma_handle_err_intr(xdev, masked, error);

        return IRQ_HANDLED;
}

/* Initialization operations */

static struct xilinx_dpdma_chan *
xilinx_dpdma_chan_probe(struct device_node *node,
                        struct xilinx_dpdma_device *xdev)
{
        struct xilinx_dpdma_chan *chan;

        chan = devm_kzalloc(xdev->dev, sizeof(*chan), GFP_KERNEL);
        if (!chan)
                return ERR_PTR(-ENOMEM);

        if (of_device_is_compatible(node, "xlnx,video0")) {
                chan->id = VIDEO0;
        } else if (of_device_is_compatible(node, "xlnx,video1")) {
                chan->id = VIDEO1;
        } else if (of_device_is_compatible(node, "xlnx,video2")) {
                chan->id = VIDEO2;
        } else if (of_device_is_compatible(node, "xlnx,graphics")) {
                chan->id = GRAPHICS;
        } else if (of_device_is_compatible(node, "xlnx,audio0")) {
                chan->id = AUDIO0;
        } else if (of_device_is_compatible(node, "xlnx,audio1")) {
                chan->id = AUDIO1;
        } else {
                dev_err(xdev->dev, "invalid channel compatible string in DT\n");
                return ERR_PTR(-EINVAL);
        }

        chan->reg = xdev->reg + XILINX_DPDMA_CH_BASE + XILINX_DPDMA_CH_OFFSET *
                    chan->id;
        chan->status = IDLE;

        spin_lock_init(&chan->lock);
        INIT_LIST_HEAD(&chan->done_list);
        init_waitqueue_head(&chan->wait_to_stop);

        tasklet_init(&chan->done_task, xilinx_dpdma_chan_done_task,
                     (unsigned long)chan);
        tasklet_init(&chan->err_task, xilinx_dpdma_chan_err_task,
                     (unsigned long)chan);

        chan->common.device = &xdev->common;
        chan->xdev = xdev;

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

        return chan;
}

static void xilinx_dpdma_chan_remove(struct xilinx_dpdma_chan *chan)
{
        tasklet_kill(&chan->err_task);
        tasklet_kill(&chan->done_task);
        list_del(&chan->common.device_node);
}

static struct dma_chan *of_dma_xilinx_xlate(struct of_phandle_args *dma_spec,
                                            struct of_dma *ofdma)
{
        struct xilinx_dpdma_device *xdev = ofdma->of_dma_data;
        uint32_t chan_id = dma_spec->args[0];

        if (chan_id >= XILINX_DPDMA_NUM_CHAN)
                return NULL;

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

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

static int xilinx_dpdma_probe(struct platform_device *pdev)
{
        struct xilinx_dpdma_device *xdev;
        struct xilinx_dpdma_chan *chan;
        struct dma_device *ddev;
        struct resource *res;
        struct device_node *node, *child;
        u32 i, freq;
        int irq, ret;

        xdev = devm_kzalloc(&pdev->dev, sizeof(*xdev), GFP_KERNEL);
        if (!xdev)
                return -ENOMEM;

        xdev->dev = &pdev->dev;
        ddev = &xdev->common;
        ddev->dev = &pdev->dev;
        node = xdev->dev->of_node;

        xdev->axi_clk = devm_clk_get(xdev->dev, "axi_clk");
        if (IS_ERR(xdev->axi_clk))
                return PTR_ERR(xdev->axi_clk);

        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        xdev->reg = devm_ioremap_resource(&pdev->dev, res);
        if (IS_ERR(xdev->reg))
                return PTR_ERR(xdev->reg);

        irq = platform_get_irq(pdev, 0);
        if (irq < 0) {
                dev_err(xdev->dev, "failed to get platform irq\n");
                return irq;
        }

        ret = devm_request_irq(xdev->dev, irq, xilinx_dpdma_irq_handler,
                               IRQF_SHARED, dev_name(xdev->dev), xdev);
        if (ret) {
                dev_err(xdev->dev, "failed to request IRQ\n");
                return ret;
        }

        INIT_LIST_HEAD(&xdev->common.channels);
        dma_cap_set(DMA_SLAVE, ddev->cap_mask);
        dma_cap_set(DMA_PRIVATE, ddev->cap_mask);
        dma_cap_set(DMA_CYCLIC, ddev->cap_mask);
        dma_cap_set(DMA_INTERLEAVE, ddev->cap_mask);
        ddev->copy_align = fls(XILINX_DPDMA_ALIGN_BYTES - 1);

        ddev->device_alloc_chan_resources = xilinx_dpdma_alloc_chan_resources;
        ddev->device_free_chan_resources = xilinx_dpdma_free_chan_resources;
        ddev->device_prep_slave_sg = xilinx_dpdma_prep_slave_sg;
        ddev->device_prep_dma_cyclic = xilinx_dpdma_prep_dma_cyclic;
        ddev->device_prep_interleaved_dma = xilinx_dpdma_prep_interleaved_dma;
        ddev->device_tx_status = xilinx_dpdma_tx_status;
        ddev->device_issue_pending = xilinx_dpdma_issue_pending;
        ddev->device_config = xilinx_dpdma_config;
        ddev->device_pause = xilinx_dpdma_pause;
        ddev->device_resume = xilinx_dpdma_resume;
        ddev->device_terminate_all = xilinx_dpdma_terminate_all;
        ddev->src_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_UNDEFINED);
        ddev->directions = BIT(DMA_MEM_TO_DEV);
        ddev->residue_granularity = DMA_RESIDUE_GRANULARITY_DESCRIPTOR;

        for_each_child_of_node(node, child) {
                chan = xilinx_dpdma_chan_probe(child, xdev);
                if (IS_ERR(chan)) {
                        dev_err(xdev->dev, "failed to probe a channel\n");
                        ret = PTR_ERR(chan);
                        goto error;
                }
        }

        xdev->ext_addr = sizeof(dma_addr_t) > 4;
        if (xdev->ext_addr)
                xdev->desc_addr = xilinx_dpdma_sw_desc_addr_64;
        else
                xdev->desc_addr = xilinx_dpdma_sw_desc_addr_32;

        ret = clk_prepare_enable(xdev->axi_clk);
        if (ret) {
                dev_err(xdev->dev, "failed to enable the axi clock\n");
                goto error;
        }

        ret = of_property_read_u32(node, "xlnx,axi-clock-freq", &freq);
        if (ret < 0) {
                dev_dbg(xdev->dev, "No axi clock freq in DT. Set to 533Mhz\n");
                freq = 533000000;
        }

        ret = clk_set_rate(xdev->axi_clk, freq);
        if (ret) {
                dev_err(xdev->dev, "failed to set the axi clock\n");
                return ret;
        }

        dev_dbg(xdev->dev, "axi clock freq: req = %u act = %lu\n", freq,
                clk_get_rate(xdev->axi_clk));

        ret = dma_async_device_register(ddev);
        if (ret) {
                dev_err(xdev->dev, "failed to enable the axi clock\n");
                goto error_dma_async;
        }

        ret = of_dma_controller_register(xdev->dev->of_node,
                                         of_dma_xilinx_xlate, ddev);
        if (ret) {
                dev_err(xdev->dev, "failed to register DMA to DT DMA helper\n");
                goto error_of_dma;
        }

        xilinx_dpdma_enable_intr(xdev);

        dev_info(&pdev->dev, "Xilinx DPDMA engine is probed\n");

        return 0;

error_of_dma:
        dma_async_device_unregister(ddev);
error_dma_async:
        clk_disable_unprepare(xdev->axi_clk);
error:
        for (i = 0; i < XILINX_DPDMA_NUM_CHAN; i++)
                if (xdev->chan[i])
                        xilinx_dpdma_chan_remove(xdev->chan[i]);

        return ret;
}

static int xilinx_dpdma_remove(struct platform_device *pdev)
{
        struct xilinx_dpdma_device *xdev;
        unsigned int i;

        xdev = platform_get_drvdata(pdev);

        xilinx_dpdma_disable_intr(xdev);
        of_dma_controller_free(pdev->dev.of_node);
        dma_async_device_unregister(&xdev->common);
        clk_disable_unprepare(xdev->axi_clk);

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

        return 0;
}

static const struct of_device_id xilinx_dpdma_of_match[] = {
        { .compatible = "xlnx,dpdma",},
        { /* end of table */ },
};
MODULE_DEVICE_TABLE(of, xilinx_dpdma_of_match);

static struct platform_driver xilinx_dpdma_driver = {
        .probe                  = xilinx_dpdma_probe,
        .remove                 = xilinx_dpdma_remove,
        .driver                 = {
                .name           = "xilinx-dpdma",
                .of_match_table = xilinx_dpdma_of_match,
        },
};

module_platform_driver(xilinx_dpdma_driver);

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