// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * DMA driver for Xilinx DMA/Bridge Subsystem
 *
 * Copyright (C) 2017-2020 Xilinx, Inc. All rights reserved.
 * Copyright (C) 2022, Advanced Micro Devices, Inc.
 */

/*
 * The DMA/Bridge Subsystem for PCI Express allows for the movement of data
 * between Host memory and the DMA subsystem. It does this by operating on
 * 'descriptors' that contain information about the source, destination and
 * amount of data to transfer. These direct memory transfers can be both in
 * the Host to Card (H2C) and Card to Host (C2H) transfers. The DMA can be
 * configured to have a single AXI4 Master interface shared by all channels
 * or one AXI4-Stream interface for each channel enabled. Memory transfers are
 * specified on a per-channel basis in descriptor linked lists, which the DMA
 * fetches from host memory and processes. Events such as descriptor completion
 * and errors are signaled using interrupts. The core also provides up to 16
 * user interrupt wires that generate interrupts to the host.
 */

#include <linux/mod_devicetable.h>
#include <linux/bitfield.h>
#include <linux/dmapool.h>
#include <linux/regmap.h>
#include <linux/dmaengine.h>
#include <linux/dma/amd_xdma.h>
#include <linux/platform_device.h>
#include <linux/platform_data/amd_xdma.h>
#include <linux/dma-mapping.h>
#include <linux/pci.h>
#include "../virt-dma.h"
#include "xdma-regs.h"

/* mmio regmap config for all XDMA registers */
static const struct regmap_config xdma_regmap_config = {
        .reg_bits = 32,
        .val_bits = 32,
        .reg_stride = 4,
        .max_register = XDMA_MAX_REG_OFFSET,
};

/**
 * struct xdma_desc_block - Descriptor block
 * @virt_addr: Virtual address of block start
 * @dma_addr: DMA address of block start
 */
struct xdma_desc_block {
        void            *virt_addr;
        dma_addr_t      dma_addr;
};

/**
 * struct xdma_chan - Driver specific DMA channel structure
 * @vchan: Virtual channel
 * @xdev_hdl: Pointer to DMA device structure
 * @base: Offset of channel registers
 * @desc_pool: Descriptor pool
 * @busy: Busy flag of the channel
 * @dir: Transferring direction of the channel
 * @cfg: Transferring config of the channel
 * @irq: IRQ assigned to the channel
 */
struct xdma_chan {
        struct virt_dma_chan            vchan;
        void                            *xdev_hdl;
        u32                             base;
        struct dma_pool                 *desc_pool;
        bool                            busy;
        enum dma_transfer_direction     dir;
        struct dma_slave_config         cfg;
        u32                             irq;
        struct completion               last_interrupt;
        bool                            stop_requested;
};

/**
 * struct xdma_desc - DMA desc structure
 * @vdesc: Virtual DMA descriptor
 * @chan: DMA channel pointer
 * @dir: Transferring direction of the request
 * @desc_blocks: Hardware descriptor blocks
 * @dblk_num: Number of hardware descriptor blocks
 * @desc_num: Number of hardware descriptors
 * @completed_desc_num: Completed hardware descriptors
 * @cyclic: Cyclic transfer vs. scatter-gather
 * @interleaved_dma: Interleaved DMA transfer
 * @periods: Number of periods in the cyclic transfer
 * @period_size: Size of a period in bytes in cyclic transfers
 * @frames_left: Number of frames left in interleaved DMA transfer
 * @error: tx error flag
 */
struct xdma_desc {
        struct virt_dma_desc            vdesc;
        struct xdma_chan                *chan;
        enum dma_transfer_direction     dir;
        struct xdma_desc_block          *desc_blocks;
        u32                             dblk_num;
        u32                             desc_num;
        u32                             completed_desc_num;
        bool                            cyclic;
        bool                            interleaved_dma;
        u32                             periods;
        u32                             period_size;
        u32                             frames_left;
        bool                            error;
};

#define XDMA_DEV_STATUS_REG_DMA         BIT(0)
#define XDMA_DEV_STATUS_INIT_MSIX       BIT(1)

/**
 * struct xdma_device - DMA device structure
 * @pdev: Platform device pointer
 * @dma_dev: DMA device structure
 * @rmap: MMIO regmap for DMA registers
 * @h2c_chans: Host to Card channels
 * @c2h_chans: Card to Host channels
 * @h2c_chan_num: Number of H2C channels
 * @c2h_chan_num: Number of C2H channels
 * @irq_start: Start IRQ assigned to device
 * @irq_num: Number of IRQ assigned to device
 * @status: Initialization status
 */
struct xdma_device {
        struct platform_device  *pdev;
        struct dma_device       dma_dev;
        struct regmap           *rmap;
        struct xdma_chan        *h2c_chans;
        struct xdma_chan        *c2h_chans;
        u32                     h2c_chan_num;
        u32                     c2h_chan_num;
        u32                     irq_start;
        u32                     irq_num;
        u32                     status;
};

#define xdma_err(xdev, fmt, args...)                                    \
        dev_err(&(xdev)->pdev->dev, fmt, ##args)
#define XDMA_CHAN_NUM(_xd) ({                                           \
        typeof(_xd) (xd) = (_xd);                                       \
        ((xd)->h2c_chan_num + (xd)->c2h_chan_num); })

/* Get the last desc in a desc block */
static inline void *xdma_blk_last_desc(struct xdma_desc_block *block)
{
        return block->virt_addr + (XDMA_DESC_ADJACENT - 1) * XDMA_DESC_SIZE;
}

/**
 * xdma_link_sg_desc_blocks - Link SG descriptor blocks for DMA transfer
 * @sw_desc: Tx descriptor pointer
 */
static void xdma_link_sg_desc_blocks(struct xdma_desc *sw_desc)
{
        struct xdma_desc_block *block;
        u32 last_blk_desc, desc_control;
        struct xdma_hw_desc *desc;
        int i;

        desc_control = XDMA_DESC_CONTROL(XDMA_DESC_ADJACENT, 0);
        for (i = 1; i < sw_desc->dblk_num; i++) {
                block = &sw_desc->desc_blocks[i - 1];
                desc = xdma_blk_last_desc(block);

                if (!(i & XDMA_DESC_BLOCK_MASK)) {
                        desc->control = cpu_to_le32(XDMA_DESC_CONTROL_LAST);
                        continue;
                }
                desc->control = cpu_to_le32(desc_control);
                desc->next_desc = cpu_to_le64(block[1].dma_addr);
        }

        /* update the last block */
        last_blk_desc = (sw_desc->desc_num - 1) & XDMA_DESC_ADJACENT_MASK;
        if (((sw_desc->dblk_num - 1) & XDMA_DESC_BLOCK_MASK) > 0) {
                block = &sw_desc->desc_blocks[sw_desc->dblk_num - 2];
                desc = xdma_blk_last_desc(block);
                desc_control = XDMA_DESC_CONTROL(last_blk_desc + 1, 0);
                desc->control = cpu_to_le32(desc_control);
        }

        block = &sw_desc->desc_blocks[sw_desc->dblk_num - 1];
        desc = block->virt_addr + last_blk_desc * XDMA_DESC_SIZE;
        desc->control = cpu_to_le32(XDMA_DESC_CONTROL_LAST);
}

/**
 * xdma_link_cyclic_desc_blocks - Link cyclic descriptor blocks for DMA transfer
 * @sw_desc: Tx descriptor pointer
 */
static void xdma_link_cyclic_desc_blocks(struct xdma_desc *sw_desc)
{
        struct xdma_desc_block *block;
        struct xdma_hw_desc *desc;
        int i;

        block = sw_desc->desc_blocks;
        for (i = 0; i < sw_desc->desc_num - 1; i++) {
                desc = block->virt_addr + i * XDMA_DESC_SIZE;
                desc->next_desc = cpu_to_le64(block->dma_addr + ((i + 1) * XDMA_DESC_SIZE));
        }
        desc = block->virt_addr + i * XDMA_DESC_SIZE;
        desc->next_desc = cpu_to_le64(block->dma_addr);
}

static inline struct xdma_chan *to_xdma_chan(struct dma_chan *chan)
{
        return container_of(chan, struct xdma_chan, vchan.chan);
}

static inline struct xdma_desc *to_xdma_desc(struct virt_dma_desc *vdesc)
{
        return container_of(vdesc, struct xdma_desc, vdesc);
}

/**
 * xdma_channel_init - Initialize DMA channel registers
 * @chan: DMA channel pointer
 */
static int xdma_channel_init(struct xdma_chan *chan)
{
        struct xdma_device *xdev = chan->xdev_hdl;
        int ret;

        ret = regmap_write(xdev->rmap, chan->base + XDMA_CHAN_CONTROL_W1C,
                           CHAN_CTRL_NON_INCR_ADDR);
        if (ret)
                return ret;

        ret = regmap_write(xdev->rmap, chan->base + XDMA_CHAN_INTR_ENABLE,
                           CHAN_IM_ALL);
        if (ret)
                return ret;

        return 0;
}

/**
 * xdma_free_desc - Free descriptor
 * @vdesc: Virtual DMA descriptor
 */
static void xdma_free_desc(struct virt_dma_desc *vdesc)
{
        struct xdma_desc *sw_desc;
        int i;

        sw_desc = to_xdma_desc(vdesc);
        for (i = 0; i < sw_desc->dblk_num; i++) {
                if (!sw_desc->desc_blocks[i].virt_addr)
                        break;
                dma_pool_free(sw_desc->chan->desc_pool,
                              sw_desc->desc_blocks[i].virt_addr,
                              sw_desc->desc_blocks[i].dma_addr);
        }
        kfree(sw_desc->desc_blocks);
        kfree(sw_desc);
}

/**
 * xdma_alloc_desc - Allocate descriptor
 * @chan: DMA channel pointer
 * @desc_num: Number of hardware descriptors
 * @cyclic: Whether this is a cyclic transfer
 */
static struct xdma_desc *
xdma_alloc_desc(struct xdma_chan *chan, u32 desc_num, bool cyclic)
{
        struct xdma_desc *sw_desc;
        struct xdma_hw_desc *desc;
        dma_addr_t dma_addr;
        u32 dblk_num;
        u32 control;
        void *addr;
        int i, j;

        sw_desc = kzalloc_obj(*sw_desc, GFP_NOWAIT);
        if (!sw_desc)
                return NULL;

        sw_desc->chan = chan;
        sw_desc->desc_num = desc_num;
        sw_desc->cyclic = cyclic;
        sw_desc->error = false;
        dblk_num = DIV_ROUND_UP(desc_num, XDMA_DESC_ADJACENT);
        sw_desc->desc_blocks = kzalloc_objs(*sw_desc->desc_blocks, dblk_num,
                                            GFP_NOWAIT);
        if (!sw_desc->desc_blocks)
                goto failed;

        if (cyclic)
                control = XDMA_DESC_CONTROL_CYCLIC;
        else
                control = XDMA_DESC_CONTROL(1, 0);

        sw_desc->dblk_num = dblk_num;
        for (i = 0; i < sw_desc->dblk_num; i++) {
                addr = dma_pool_alloc(chan->desc_pool, GFP_NOWAIT, &dma_addr);
                if (!addr)
                        goto failed;

                sw_desc->desc_blocks[i].virt_addr = addr;
                sw_desc->desc_blocks[i].dma_addr = dma_addr;
                for (j = 0, desc = addr; j < XDMA_DESC_ADJACENT; j++)
                        desc[j].control = cpu_to_le32(control);
        }

        if (cyclic)
                xdma_link_cyclic_desc_blocks(sw_desc);
        else
                xdma_link_sg_desc_blocks(sw_desc);

        return sw_desc;

failed:
        xdma_free_desc(&sw_desc->vdesc);
        return NULL;
}

/**
 * xdma_xfer_start - Start DMA transfer
 * @xchan: DMA channel pointer
 */
static int xdma_xfer_start(struct xdma_chan *xchan)
{
        struct virt_dma_desc *vd = vchan_next_desc(&xchan->vchan);
        struct xdma_device *xdev = xchan->xdev_hdl;
        struct xdma_desc_block *block;
        u32 val, completed_blocks;
        struct xdma_desc *desc;
        int ret;

        /*
         * check if there is not any submitted descriptor or channel is busy.
         * vchan lock should be held where this function is called.
         */
        if (!vd || xchan->busy)
                return -EINVAL;

        /* clear run stop bit to get ready for transfer */
        ret = regmap_write(xdev->rmap, xchan->base + XDMA_CHAN_CONTROL_W1C,
                           CHAN_CTRL_RUN_STOP);
        if (ret)
                return ret;

        desc = to_xdma_desc(vd);
        if (desc->dir != xchan->dir) {
                xdma_err(xdev, "incorrect request direction");
                return -EINVAL;
        }

        /* set DMA engine to the first descriptor block */
        completed_blocks = desc->completed_desc_num / XDMA_DESC_ADJACENT;
        block = &desc->desc_blocks[completed_blocks];
        val = lower_32_bits(block->dma_addr);
        ret = regmap_write(xdev->rmap, xchan->base + XDMA_SGDMA_DESC_LO, val);
        if (ret)
                return ret;

        val = upper_32_bits(block->dma_addr);
        ret = regmap_write(xdev->rmap, xchan->base + XDMA_SGDMA_DESC_HI, val);
        if (ret)
                return ret;

        if (completed_blocks + 1 == desc->dblk_num)
                val = (desc->desc_num - 1) & XDMA_DESC_ADJACENT_MASK;
        else
                val = XDMA_DESC_ADJACENT - 1;
        ret = regmap_write(xdev->rmap, xchan->base + XDMA_SGDMA_DESC_ADJ, val);
        if (ret)
                return ret;

        /* kick off DMA transfer */
        ret = regmap_write(xdev->rmap, xchan->base + XDMA_CHAN_CONTROL,
                           CHAN_CTRL_START);
        if (ret)
                return ret;

        xchan->busy = true;
        xchan->stop_requested = false;
        reinit_completion(&xchan->last_interrupt);

        return 0;
}

/**
 * xdma_xfer_stop - Stop DMA transfer
 * @xchan: DMA channel pointer
 */
static int xdma_xfer_stop(struct xdma_chan *xchan)
{
        struct xdma_device *xdev = xchan->xdev_hdl;

        /* clear run stop bit to prevent any further auto-triggering */
        return regmap_write(xdev->rmap, xchan->base + XDMA_CHAN_CONTROL_W1C,
                            CHAN_CTRL_RUN_STOP);
}

/**
 * xdma_alloc_channels - Detect and allocate DMA channels
 * @xdev: DMA device pointer
 * @dir: Channel direction
 */
static int xdma_alloc_channels(struct xdma_device *xdev,
                               enum dma_transfer_direction dir)
{
        struct xdma_platdata *pdata = dev_get_platdata(&xdev->pdev->dev);
        struct xdma_chan **chans, *xchan;
        u32 base, identifier, target;
        u32 *chan_num;
        int i, j, ret;

        if (dir == DMA_MEM_TO_DEV) {
                base = XDMA_CHAN_H2C_OFFSET;
                target = XDMA_CHAN_H2C_TARGET;
                chans = &xdev->h2c_chans;
                chan_num = &xdev->h2c_chan_num;
        } else if (dir == DMA_DEV_TO_MEM) {
                base = XDMA_CHAN_C2H_OFFSET;
                target = XDMA_CHAN_C2H_TARGET;
                chans = &xdev->c2h_chans;
                chan_num = &xdev->c2h_chan_num;
        } else {
                xdma_err(xdev, "invalid direction specified");
                return -EINVAL;
        }

        /* detect number of available DMA channels */
        for (i = 0, *chan_num = 0; i < pdata->max_dma_channels; i++) {
                ret = regmap_read(xdev->rmap, base + i * XDMA_CHAN_STRIDE,
                                  &identifier);
                if (ret)
                        return ret;

                /* check if it is available DMA channel */
                if (XDMA_CHAN_CHECK_TARGET(identifier, target))
                        (*chan_num)++;
        }

        if (!*chan_num) {
                xdma_err(xdev, "does not probe any channel");
                return -EINVAL;
        }

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

        for (i = 0, j = 0; i < pdata->max_dma_channels; i++) {
                ret = regmap_read(xdev->rmap, base + i * XDMA_CHAN_STRIDE,
                                  &identifier);
                if (ret)
                        return ret;

                if (!XDMA_CHAN_CHECK_TARGET(identifier, target))
                        continue;

                if (j == *chan_num) {
                        xdma_err(xdev, "invalid channel number");
                        return -EIO;
                }

                /* init channel structure and hardware */
                xchan = &(*chans)[j];
                xchan->xdev_hdl = xdev;
                xchan->base = base + i * XDMA_CHAN_STRIDE;
                xchan->dir = dir;
                xchan->stop_requested = false;
                init_completion(&xchan->last_interrupt);

                ret = xdma_channel_init(xchan);
                if (ret)
                        return ret;
                xchan->vchan.desc_free = xdma_free_desc;
                vchan_init(&xchan->vchan, &xdev->dma_dev);

                j++;
        }

        dev_info(&xdev->pdev->dev, "configured %d %s channels", j,
                 (dir == DMA_MEM_TO_DEV) ? "H2C" : "C2H");

        return 0;
}

/**
 * xdma_issue_pending - Issue pending transactions
 * @chan: DMA channel pointer
 */
static void xdma_issue_pending(struct dma_chan *chan)
{
        struct xdma_chan *xdma_chan = to_xdma_chan(chan);
        unsigned long flags;

        spin_lock_irqsave(&xdma_chan->vchan.lock, flags);
        if (vchan_issue_pending(&xdma_chan->vchan))
                xdma_xfer_start(xdma_chan);
        spin_unlock_irqrestore(&xdma_chan->vchan.lock, flags);
}

/**
 * xdma_terminate_all - Terminate all transactions
 * @chan: DMA channel pointer
 */
static int xdma_terminate_all(struct dma_chan *chan)
{
        struct xdma_chan *xdma_chan = to_xdma_chan(chan);
        struct virt_dma_desc *vd;
        unsigned long flags;
        LIST_HEAD(head);

        xdma_xfer_stop(xdma_chan);

        spin_lock_irqsave(&xdma_chan->vchan.lock, flags);

        xdma_chan->busy = false;
        xdma_chan->stop_requested = true;
        vd = vchan_next_desc(&xdma_chan->vchan);
        if (vd) {
                list_del(&vd->node);
                dma_cookie_complete(&vd->tx);
                vchan_terminate_vdesc(vd);
        }
        vchan_get_all_descriptors(&xdma_chan->vchan, &head);
        list_splice_tail(&head, &xdma_chan->vchan.desc_terminated);

        spin_unlock_irqrestore(&xdma_chan->vchan.lock, flags);

        return 0;
}

/**
 * xdma_synchronize - Synchronize terminated transactions
 * @chan: DMA channel pointer
 */
static void xdma_synchronize(struct dma_chan *chan)
{
        struct xdma_chan *xdma_chan = to_xdma_chan(chan);
        struct xdma_device *xdev = xdma_chan->xdev_hdl;
        int st = 0;

        /* If the engine continues running, wait for the last interrupt */
        regmap_read(xdev->rmap, xdma_chan->base + XDMA_CHAN_STATUS, &st);
        if (st & XDMA_CHAN_STATUS_BUSY)
                wait_for_completion_timeout(&xdma_chan->last_interrupt, msecs_to_jiffies(1000));

        vchan_synchronize(&xdma_chan->vchan);
}

/**
 * xdma_fill_descs() - Fill hardware descriptors for one contiguous memory chunk.
 *                     More than one descriptor will be used if the size is bigger
 *                     than XDMA_DESC_BLEN_MAX.
 * @sw_desc: Descriptor container
 * @src_addr: First value for the ->src_addr field
 * @dst_addr: First value for the ->dst_addr field
 * @size: Size of the contiguous memory block
 * @filled_descs_num: Index of the first descriptor to take care of in @sw_desc
 */
static inline u32 xdma_fill_descs(struct xdma_desc *sw_desc, u64 src_addr,
                                  u64 dst_addr, u32 size, u32 filled_descs_num)
{
        u32 left = size, len, desc_num = filled_descs_num;
        struct xdma_desc_block *dblk;
        struct xdma_hw_desc *desc;

        dblk = sw_desc->desc_blocks + (desc_num / XDMA_DESC_ADJACENT);
        desc = dblk->virt_addr;
        desc += desc_num & XDMA_DESC_ADJACENT_MASK;
        do {
                len = min_t(u32, left, XDMA_DESC_BLEN_MAX);
                /* set hardware descriptor */
                desc->bytes = cpu_to_le32(len);
                desc->src_addr = cpu_to_le64(src_addr);
                desc->dst_addr = cpu_to_le64(dst_addr);
                if (!(++desc_num & XDMA_DESC_ADJACENT_MASK))
                        desc = (++dblk)->virt_addr;
                else
                        desc++;

                src_addr += len;
                dst_addr += len;
                left -= len;
        } while (left);

        return desc_num - filled_descs_num;
}

/**
 * xdma_prep_device_sg - prepare a descriptor for a DMA transaction
 * @chan: DMA channel pointer
 * @sgl: Transfer scatter gather list
 * @sg_len: Length of scatter gather list
 * @dir: Transfer direction
 * @flags: transfer ack flags
 * @context: APP words of the descriptor
 */
static struct dma_async_tx_descriptor *
xdma_prep_device_sg(struct dma_chan *chan, struct scatterlist *sgl,
                    unsigned int sg_len, enum dma_transfer_direction dir,
                    unsigned long flags, void *context)
{
        struct xdma_chan *xdma_chan = to_xdma_chan(chan);
        struct dma_async_tx_descriptor *tx_desc;
        struct xdma_desc *sw_desc;
        u64 addr, dev_addr, *src, *dst;
        u32 desc_num, i;
        struct scatterlist *sg;

        desc_num = sg_nents_for_dma(sgl, sg_len, XDMA_DESC_BLEN_MAX);
        sw_desc = xdma_alloc_desc(xdma_chan, desc_num, false);
        if (!sw_desc)
                return NULL;
        sw_desc->dir = dir;
        sw_desc->cyclic = false;
        sw_desc->interleaved_dma = false;

        if (dir == DMA_MEM_TO_DEV) {
                dev_addr = xdma_chan->cfg.dst_addr;
                src = &addr;
                dst = &dev_addr;
        } else {
                dev_addr = xdma_chan->cfg.src_addr;
                src = &dev_addr;
                dst = &addr;
        }

        desc_num = 0;
        for_each_sg(sgl, sg, sg_len, i) {
                addr = sg_dma_address(sg);
                desc_num += xdma_fill_descs(sw_desc, *src, *dst, sg_dma_len(sg), desc_num);
                dev_addr += sg_dma_len(sg);
        }

        tx_desc = vchan_tx_prep(&xdma_chan->vchan, &sw_desc->vdesc, flags);
        if (!tx_desc)
                goto failed;

        return tx_desc;

failed:
        xdma_free_desc(&sw_desc->vdesc);

        return NULL;
}

/**
 * xdma_prep_dma_cyclic - prepare for cyclic DMA transactions
 * @chan: DMA channel pointer
 * @address: Device DMA address to access
 * @size: Total length to transfer
 * @period_size: Period size to use for each transfer
 * @dir: Transfer direction
 * @flags: Transfer ack flags
 */
static struct dma_async_tx_descriptor *
xdma_prep_dma_cyclic(struct dma_chan *chan, dma_addr_t address,
                     size_t size, size_t period_size,
                     enum dma_transfer_direction dir,
                     unsigned long flags)
{
        struct xdma_chan *xdma_chan = to_xdma_chan(chan);
        struct xdma_device *xdev = xdma_chan->xdev_hdl;
        unsigned int periods = size / period_size;
        struct dma_async_tx_descriptor *tx_desc;
        struct xdma_desc *sw_desc;
        u64 addr, dev_addr, *src, *dst;
        u32 desc_num;
        unsigned int i;

        /*
         * Simplify the whole logic by preventing an abnormally high number of
         * periods and periods size.
         */
        if (period_size > XDMA_DESC_BLEN_MAX) {
                xdma_err(xdev, "period size limited to %lu bytes\n", XDMA_DESC_BLEN_MAX);
                return NULL;
        }

        if (periods > XDMA_DESC_ADJACENT) {
                xdma_err(xdev, "number of periods limited to %u\n", XDMA_DESC_ADJACENT);
                return NULL;
        }

        sw_desc = xdma_alloc_desc(xdma_chan, periods, true);
        if (!sw_desc)
                return NULL;

        sw_desc->periods = periods;
        sw_desc->period_size = period_size;
        sw_desc->dir = dir;
        sw_desc->interleaved_dma = false;

        addr = address;
        if (dir == DMA_MEM_TO_DEV) {
                dev_addr = xdma_chan->cfg.dst_addr;
                src = &addr;
                dst = &dev_addr;
        } else {
                dev_addr = xdma_chan->cfg.src_addr;
                src = &dev_addr;
                dst = &addr;
        }

        desc_num = 0;
        for (i = 0; i < periods; i++) {
                desc_num += xdma_fill_descs(sw_desc, *src, *dst, period_size, desc_num);
                addr += period_size;
        }

        tx_desc = vchan_tx_prep(&xdma_chan->vchan, &sw_desc->vdesc, flags);
        if (!tx_desc)
                goto failed;

        return tx_desc;

failed:
        xdma_free_desc(&sw_desc->vdesc);

        return NULL;
}

/**
 * xdma_prep_interleaved_dma - Prepare virtual descriptor for interleaved DMA transfers
 * @chan: DMA channel
 * @xt: DMA transfer template
 * @flags: tx flags
 */
static struct dma_async_tx_descriptor *
xdma_prep_interleaved_dma(struct dma_chan *chan,
                          struct dma_interleaved_template *xt,
                          unsigned long flags)
{
        int i;
        u32 desc_num = 0, period_size = 0;
        struct dma_async_tx_descriptor *tx_desc;
        struct xdma_chan *xchan = to_xdma_chan(chan);
        struct xdma_desc *sw_desc;
        u64 src_addr, dst_addr;

        for (i = 0; i < xt->frame_size; ++i)
                desc_num += DIV_ROUND_UP(xt->sgl[i].size, XDMA_DESC_BLEN_MAX);

        sw_desc = xdma_alloc_desc(xchan, desc_num, false);
        if (!sw_desc)
                return NULL;
        sw_desc->dir = xt->dir;
        sw_desc->interleaved_dma = true;
        sw_desc->cyclic = flags & DMA_PREP_REPEAT;
        sw_desc->frames_left = xt->numf;
        sw_desc->periods = xt->numf;

        desc_num = 0;
        src_addr = xt->src_start;
        dst_addr = xt->dst_start;
        for (i = 0; i < xt->frame_size; ++i) {
                desc_num += xdma_fill_descs(sw_desc, src_addr, dst_addr, xt->sgl[i].size, desc_num);
                src_addr += dmaengine_get_src_icg(xt, &xt->sgl[i]) + (xt->src_inc ?
                                                              xt->sgl[i].size : 0);
                dst_addr += dmaengine_get_dst_icg(xt, &xt->sgl[i]) + (xt->dst_inc ?
                                                              xt->sgl[i].size : 0);
                period_size += xt->sgl[i].size;
        }
        sw_desc->period_size = period_size;

        tx_desc = vchan_tx_prep(&xchan->vchan, &sw_desc->vdesc, flags);
        if (tx_desc)
                return tx_desc;

        xdma_free_desc(&sw_desc->vdesc);
        return NULL;
}

/**
 * xdma_device_config - Configure the DMA channel
 * @chan: DMA channel
 * @cfg: channel configuration
 */
static int xdma_device_config(struct dma_chan *chan,
                              struct dma_slave_config *cfg)
{
        struct xdma_chan *xdma_chan = to_xdma_chan(chan);

        memcpy(&xdma_chan->cfg, cfg, sizeof(*cfg));

        return 0;
}

/**
 * xdma_free_chan_resources - Free channel resources
 * @chan: DMA channel
 */
static void xdma_free_chan_resources(struct dma_chan *chan)
{
        struct xdma_chan *xdma_chan = to_xdma_chan(chan);

        vchan_free_chan_resources(&xdma_chan->vchan);
        dma_pool_destroy(xdma_chan->desc_pool);
        xdma_chan->desc_pool = NULL;
}

/**
 * xdma_alloc_chan_resources - Allocate channel resources
 * @chan: DMA channel
 */
static int xdma_alloc_chan_resources(struct dma_chan *chan)
{
        struct xdma_chan *xdma_chan = to_xdma_chan(chan);
        struct xdma_device *xdev = xdma_chan->xdev_hdl;
        struct device *dev = xdev->dma_dev.dev;

        while (dev && !dev_is_pci(dev))
                dev = dev->parent;
        if (!dev) {
                xdma_err(xdev, "unable to find pci device");
                return -EINVAL;
        }

        xdma_chan->desc_pool = dma_pool_create(dma_chan_name(chan), dev, XDMA_DESC_BLOCK_SIZE,
                                               XDMA_DESC_BLOCK_ALIGN, XDMA_DESC_BLOCK_BOUNDARY);
        if (!xdma_chan->desc_pool) {
                xdma_err(xdev, "unable to allocate descriptor pool");
                return -ENOMEM;
        }

        return 0;
}

static enum dma_status xdma_tx_status(struct dma_chan *chan, dma_cookie_t cookie,
                                      struct dma_tx_state *state)
{
        struct xdma_chan *xdma_chan = to_xdma_chan(chan);
        struct xdma_desc *desc = NULL;
        struct virt_dma_desc *vd;
        enum dma_status ret;
        unsigned long flags;
        unsigned int period_idx;
        u32 residue = 0;

        ret = dma_cookie_status(chan, cookie, state);
        if (ret == DMA_COMPLETE)
                return ret;

        spin_lock_irqsave(&xdma_chan->vchan.lock, flags);

        vd = vchan_find_desc(&xdma_chan->vchan, cookie);
        if (!vd)
                goto out;

        desc = to_xdma_desc(vd);
        if (desc->error) {
                ret = DMA_ERROR;
        } else if (desc->cyclic) {
                period_idx = desc->completed_desc_num % desc->periods;
                residue = (desc->periods - period_idx) * desc->period_size;
                dma_set_residue(state, residue);
        }
out:
        spin_unlock_irqrestore(&xdma_chan->vchan.lock, flags);

        return ret;
}

/**
 * xdma_channel_isr - XDMA channel interrupt handler
 * @irq: IRQ number
 * @dev_id: Pointer to the DMA channel structure
 */
static irqreturn_t xdma_channel_isr(int irq, void *dev_id)
{
        struct xdma_chan *xchan = dev_id;
        u32 complete_desc_num = 0;
        struct xdma_device *xdev = xchan->xdev_hdl;
        struct virt_dma_desc *vd, *next_vd;
        struct xdma_desc *desc;
        int ret;
        u32 st;
        bool repeat_tx;

        spin_lock(&xchan->vchan.lock);

        if (xchan->stop_requested)
                complete(&xchan->last_interrupt);

        /* get submitted request */
        vd = vchan_next_desc(&xchan->vchan);
        if (!vd)
                goto out;

        /* Clear-on-read the status register */
        ret = regmap_read(xdev->rmap, xchan->base + XDMA_CHAN_STATUS_RC, &st);
        if (ret)
                goto out;

        desc = to_xdma_desc(vd);

        st &= XDMA_CHAN_STATUS_MASK;
        if ((st & XDMA_CHAN_ERROR_MASK) ||
            !(st & (CHAN_CTRL_IE_DESC_COMPLETED | CHAN_CTRL_IE_DESC_STOPPED))) {
                desc->error = true;
                xdma_err(xdev, "channel error, status register value: 0x%x", st);
                goto out;
        }

        ret = regmap_read(xdev->rmap, xchan->base + XDMA_CHAN_COMPLETED_DESC,
                          &complete_desc_num);
        if (ret)
                goto out;

        if (desc->interleaved_dma) {
                xchan->busy = false;
                desc->completed_desc_num += complete_desc_num;
                if (complete_desc_num == XDMA_DESC_BLOCK_NUM * XDMA_DESC_ADJACENT) {
                        xdma_xfer_start(xchan);
                        goto out;
                }

                /* last desc of any frame */
                desc->frames_left--;
                if (desc->frames_left)
                        goto out;

                /* last desc of the last frame  */
                repeat_tx = vd->tx.flags & DMA_PREP_REPEAT;
                next_vd = list_first_entry_or_null(&vd->node, struct virt_dma_desc, node);
                if (next_vd)
                        repeat_tx = repeat_tx && !(next_vd->tx.flags & DMA_PREP_LOAD_EOT);
                if (repeat_tx) {
                        desc->frames_left = desc->periods;
                        desc->completed_desc_num = 0;
                        vchan_cyclic_callback(vd);
                } else {
                        list_del(&vd->node);
                        vchan_cookie_complete(vd);
                }
                /* start (or continue) the tx of a first desc on the vc.desc_issued list, if any */
                xdma_xfer_start(xchan);
        } else if (!desc->cyclic) {
                xchan->busy = false;
                desc->completed_desc_num += complete_desc_num;

                /* if all data blocks are transferred, remove and complete the request */
                if (desc->completed_desc_num == desc->desc_num) {
                        list_del(&vd->node);
                        vchan_cookie_complete(vd);
                        goto out;
                }

                if (desc->completed_desc_num > desc->desc_num ||
                    complete_desc_num != XDMA_DESC_BLOCK_NUM * XDMA_DESC_ADJACENT)
                        goto out;

                /* transfer the rest of data */
                xdma_xfer_start(xchan);
        } else {
                desc->completed_desc_num = complete_desc_num;
                vchan_cyclic_callback(vd);
        }

out:
        spin_unlock(&xchan->vchan.lock);
        return IRQ_HANDLED;
}

/**
 * xdma_irq_fini - Uninitialize IRQ
 * @xdev: DMA device pointer
 */
static void xdma_irq_fini(struct xdma_device *xdev)
{
        int i;

        /* disable interrupt */
        regmap_write(xdev->rmap, XDMA_IRQ_CHAN_INT_EN_W1C, ~0);

        /* free irq handler */
        for (i = 0; i < xdev->h2c_chan_num; i++)
                free_irq(xdev->h2c_chans[i].irq, &xdev->h2c_chans[i]);

        for (i = 0; i < xdev->c2h_chan_num; i++)
                free_irq(xdev->c2h_chans[i].irq, &xdev->c2h_chans[i]);
}

/**
 * xdma_set_vector_reg - configure hardware IRQ registers
 * @xdev: DMA device pointer
 * @vec_tbl_start: Start of IRQ registers
 * @irq_start: Start of IRQ
 * @irq_num: Number of IRQ
 */
static int xdma_set_vector_reg(struct xdma_device *xdev, u32 vec_tbl_start,
                               u32 irq_start, u32 irq_num)
{
        u32 shift, i, val = 0;
        int ret;

        /* Each IRQ register is 32 bit and contains 4 IRQs */
        while (irq_num > 0) {
                for (i = 0; i < 4; i++) {
                        shift = XDMA_IRQ_VEC_SHIFT * i;
                        val |= irq_start << shift;
                        irq_start++;
                        irq_num--;
                        if (!irq_num)
                                break;
                }

                /* write IRQ register */
                ret = regmap_write(xdev->rmap, vec_tbl_start, val);
                if (ret)
                        return ret;
                vec_tbl_start += sizeof(u32);
                val = 0;
        }

        return 0;
}

/**
 * xdma_irq_init - initialize IRQs
 * @xdev: DMA device pointer
 */
static int xdma_irq_init(struct xdma_device *xdev)
{
        u32 irq = xdev->irq_start;
        u32 user_irq_start;
        int i, j, ret;

        /* return failure if there are not enough IRQs */
        if (xdev->irq_num < XDMA_CHAN_NUM(xdev)) {
                xdma_err(xdev, "not enough irq");
                return -EINVAL;
        }

        /* setup H2C interrupt handler */
        for (i = 0; i < xdev->h2c_chan_num; i++) {
                ret = request_irq(irq, xdma_channel_isr, 0,
                                  "xdma-h2c-channel", &xdev->h2c_chans[i]);
                if (ret) {
                        xdma_err(xdev, "H2C channel%d request irq%d failed: %d",
                                 i, irq, ret);
                        goto failed_init_h2c;
                }
                xdev->h2c_chans[i].irq = irq;
                irq++;
        }

        /* setup C2H interrupt handler */
        for (j = 0; j < xdev->c2h_chan_num; j++) {
                ret = request_irq(irq, xdma_channel_isr, 0,
                                  "xdma-c2h-channel", &xdev->c2h_chans[j]);
                if (ret) {
                        xdma_err(xdev, "C2H channel%d request irq%d failed: %d",
                                 j, irq, ret);
                        goto failed_init_c2h;
                }
                xdev->c2h_chans[j].irq = irq;
                irq++;
        }

        /* config hardware IRQ registers */
        ret = xdma_set_vector_reg(xdev, XDMA_IRQ_CHAN_VEC_NUM, 0,
                                  XDMA_CHAN_NUM(xdev));
        if (ret) {
                xdma_err(xdev, "failed to set channel vectors: %d", ret);
                goto failed_init_c2h;
        }

        /* config user IRQ registers if needed */
        user_irq_start = XDMA_CHAN_NUM(xdev);
        if (xdev->irq_num > user_irq_start) {
                ret = xdma_set_vector_reg(xdev, XDMA_IRQ_USER_VEC_NUM,
                                          user_irq_start,
                                          xdev->irq_num - user_irq_start);
                if (ret) {
                        xdma_err(xdev, "failed to set user vectors: %d", ret);
                        goto failed_init_c2h;
                }
        }

        /* enable interrupt */
        ret = regmap_write(xdev->rmap, XDMA_IRQ_CHAN_INT_EN_W1S, ~0);
        if (ret)
                goto failed_init_c2h;

        return 0;

failed_init_c2h:
        while (j--)
                free_irq(xdev->c2h_chans[j].irq, &xdev->c2h_chans[j]);
failed_init_h2c:
        while (i--)
                free_irq(xdev->h2c_chans[i].irq, &xdev->h2c_chans[i]);

        return ret;
}

static bool xdma_filter_fn(struct dma_chan *chan, void *param)
{
        struct xdma_chan *xdma_chan = to_xdma_chan(chan);
        struct xdma_chan_info *chan_info = param;

        return chan_info->dir == xdma_chan->dir;
}

/**
 * xdma_disable_user_irq - Disable user interrupt
 * @pdev: Pointer to the platform_device structure
 * @irq_num: System IRQ number
 */
void xdma_disable_user_irq(struct platform_device *pdev, u32 irq_num)
{
        struct xdma_device *xdev = platform_get_drvdata(pdev);
        u32 index;

        index = irq_num - xdev->irq_start;
        if (index < XDMA_CHAN_NUM(xdev) || index >= xdev->irq_num) {
                xdma_err(xdev, "invalid user irq number");
                return;
        }
        index -= XDMA_CHAN_NUM(xdev);

        regmap_write(xdev->rmap, XDMA_IRQ_USER_INT_EN_W1C, 1 << index);
}
EXPORT_SYMBOL(xdma_disable_user_irq);

/**
 * xdma_enable_user_irq - Enable user logic interrupt
 * @pdev: Pointer to the platform_device structure
 * @irq_num: System IRQ number
 */
int xdma_enable_user_irq(struct platform_device *pdev, u32 irq_num)
{
        struct xdma_device *xdev = platform_get_drvdata(pdev);
        u32 index;
        int ret;

        index = irq_num - xdev->irq_start;
        if (index < XDMA_CHAN_NUM(xdev) || index >= xdev->irq_num) {
                xdma_err(xdev, "invalid user irq number");
                return -EINVAL;
        }
        index -= XDMA_CHAN_NUM(xdev);

        ret = regmap_write(xdev->rmap, XDMA_IRQ_USER_INT_EN_W1S, 1 << index);
        if (ret)
                return ret;

        return 0;
}
EXPORT_SYMBOL(xdma_enable_user_irq);

/**
 * xdma_get_user_irq - Get system IRQ number
 * @pdev: Pointer to the platform_device structure
 * @user_irq_index: User logic IRQ wire index
 *
 * Return: The system IRQ number allocated for the given wire index.
 */
int xdma_get_user_irq(struct platform_device *pdev, u32 user_irq_index)
{
        struct xdma_device *xdev = platform_get_drvdata(pdev);

        if (XDMA_CHAN_NUM(xdev) + user_irq_index >= xdev->irq_num) {
                xdma_err(xdev, "invalid user irq index");
                return -EINVAL;
        }

        return xdev->irq_start + XDMA_CHAN_NUM(xdev) + user_irq_index;
}
EXPORT_SYMBOL(xdma_get_user_irq);

/**
 * xdma_remove - Driver remove function
 * @pdev: Pointer to the platform_device structure
 */
static void xdma_remove(struct platform_device *pdev)
{
        struct xdma_device *xdev = platform_get_drvdata(pdev);

        if (xdev->status & XDMA_DEV_STATUS_INIT_MSIX)
                xdma_irq_fini(xdev);

        if (xdev->status & XDMA_DEV_STATUS_REG_DMA)
                dma_async_device_unregister(&xdev->dma_dev);
}

/**
 * xdma_probe - Driver probe function
 * @pdev: Pointer to the platform_device structure
 */
static int xdma_probe(struct platform_device *pdev)
{
        struct xdma_platdata *pdata = dev_get_platdata(&pdev->dev);
        struct xdma_device *xdev;
        void __iomem *reg_base;
        struct resource *res;
        int ret = -ENODEV;

        if (pdata->max_dma_channels > XDMA_MAX_CHANNELS) {
                dev_err(&pdev->dev, "invalid max dma channels %d",
                        pdata->max_dma_channels);
                return -EINVAL;
        }

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

        platform_set_drvdata(pdev, xdev);
        xdev->pdev = pdev;

        res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
        if (!res) {
                xdma_err(xdev, "failed to get irq resource");
                goto failed;
        }
        xdev->irq_start = res->start;
        xdev->irq_num = resource_size(res);

        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        if (!res) {
                xdma_err(xdev, "failed to get io resource");
                goto failed;
        }

        reg_base = devm_ioremap_resource(&pdev->dev, res);
        if (IS_ERR(reg_base)) {
                xdma_err(xdev, "ioremap failed");
                goto failed;
        }

        xdev->rmap = devm_regmap_init_mmio(&pdev->dev, reg_base,
                                           &xdma_regmap_config);
        if (IS_ERR(xdev->rmap)) {
                xdma_err(xdev, "config regmap failed: %pe", xdev->rmap);
                goto failed;
        }
        INIT_LIST_HEAD(&xdev->dma_dev.channels);

        ret = xdma_alloc_channels(xdev, DMA_MEM_TO_DEV);
        if (ret) {
                xdma_err(xdev, "config H2C channels failed: %d", ret);
                goto failed;
        }

        ret = xdma_alloc_channels(xdev, DMA_DEV_TO_MEM);
        if (ret) {
                xdma_err(xdev, "config C2H channels failed: %d", ret);
                goto failed;
        }

        dma_cap_set(DMA_SLAVE, xdev->dma_dev.cap_mask);
        dma_cap_set(DMA_PRIVATE, xdev->dma_dev.cap_mask);
        dma_cap_set(DMA_CYCLIC, xdev->dma_dev.cap_mask);
        dma_cap_set(DMA_INTERLEAVE, xdev->dma_dev.cap_mask);
        dma_cap_set(DMA_REPEAT, xdev->dma_dev.cap_mask);
        dma_cap_set(DMA_LOAD_EOT, xdev->dma_dev.cap_mask);

        xdev->dma_dev.dev = &pdev->dev;
        xdev->dma_dev.residue_granularity = DMA_RESIDUE_GRANULARITY_SEGMENT;
        xdev->dma_dev.device_free_chan_resources = xdma_free_chan_resources;
        xdev->dma_dev.device_alloc_chan_resources = xdma_alloc_chan_resources;
        xdev->dma_dev.device_tx_status = xdma_tx_status;
        xdev->dma_dev.device_prep_slave_sg = xdma_prep_device_sg;
        xdev->dma_dev.device_config = xdma_device_config;
        xdev->dma_dev.device_issue_pending = xdma_issue_pending;
        xdev->dma_dev.device_terminate_all = xdma_terminate_all;
        xdev->dma_dev.device_synchronize = xdma_synchronize;
        xdev->dma_dev.filter.map = pdata->device_map;
        xdev->dma_dev.filter.mapcnt = pdata->device_map_cnt;
        xdev->dma_dev.filter.fn = xdma_filter_fn;
        xdev->dma_dev.device_prep_dma_cyclic = xdma_prep_dma_cyclic;
        xdev->dma_dev.device_prep_interleaved_dma = xdma_prep_interleaved_dma;

        ret = dma_async_device_register(&xdev->dma_dev);
        if (ret) {
                xdma_err(xdev, "failed to register Xilinx XDMA: %d", ret);
                goto failed;
        }
        xdev->status |= XDMA_DEV_STATUS_REG_DMA;

        ret = xdma_irq_init(xdev);
        if (ret) {
                xdma_err(xdev, "failed to init msix: %d", ret);
                goto failed;
        }
        xdev->status |= XDMA_DEV_STATUS_INIT_MSIX;

        return 0;

failed:
        xdma_remove(pdev);

        return ret;
}

static const struct platform_device_id xdma_id_table[] = {
        { "xdma", 0},
        { },
};
MODULE_DEVICE_TABLE(platform, xdma_id_table);

static struct platform_driver xdma_driver = {
        .driver         = {
                .name = "xdma",
        },
        .id_table       = xdma_id_table,
        .probe          = xdma_probe,
        .remove         = xdma_remove,
};

module_platform_driver(xdma_driver);

MODULE_DESCRIPTION("AMD XDMA driver");
MODULE_AUTHOR("XRT Team <runtimeca39d@amd.com>");
MODULE_LICENSE("GPL");