// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Copyright (C) 2015-2016 Marvell International Ltd.

 */

#include <linux/clk.h>
#include <linux/dma-mapping.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/msi.h>
#include <linux/of.h>
#include <linux/of_irq.h>
#include <linux/platform_device.h>
#include <linux/spinlock.h>

#include "dmaengine.h"

/* DMA Engine Registers */
#define MV_XOR_V2_DMA_DESQ_BALR_OFF                     0x000
#define MV_XOR_V2_DMA_DESQ_BAHR_OFF                     0x004
#define MV_XOR_V2_DMA_DESQ_SIZE_OFF                     0x008
#define MV_XOR_V2_DMA_DESQ_DONE_OFF                     0x00C
#define   MV_XOR_V2_DMA_DESQ_DONE_PENDING_MASK          0x7FFF
#define   MV_XOR_V2_DMA_DESQ_DONE_PENDING_SHIFT         0
#define   MV_XOR_V2_DMA_DESQ_DONE_READ_PTR_MASK         0x1FFF
#define   MV_XOR_V2_DMA_DESQ_DONE_READ_PTR_SHIFT        16
#define MV_XOR_V2_DMA_DESQ_ARATTR_OFF                   0x010
#define   MV_XOR_V2_DMA_DESQ_ATTR_CACHE_MASK            0x3F3F
#define   MV_XOR_V2_DMA_DESQ_ATTR_OUTER_SHAREABLE       0x202
#define   MV_XOR_V2_DMA_DESQ_ATTR_CACHEABLE             0x3C3C
#define MV_XOR_V2_DMA_IMSG_CDAT_OFF                     0x014
#define MV_XOR_V2_DMA_IMSG_THRD_OFF                     0x018
#define   MV_XOR_V2_DMA_IMSG_THRD_MASK                  0x7FFF
#define   MV_XOR_V2_DMA_IMSG_TIMER_EN                   BIT(18)
#define MV_XOR_V2_DMA_DESQ_AWATTR_OFF                   0x01C
  /* Same flags as MV_XOR_V2_DMA_DESQ_ARATTR_OFF */
#define MV_XOR_V2_DMA_DESQ_ALLOC_OFF                    0x04C
#define   MV_XOR_V2_DMA_DESQ_ALLOC_WRPTR_MASK           0xFFFF
#define   MV_XOR_V2_DMA_DESQ_ALLOC_WRPTR_SHIFT          16
#define MV_XOR_V2_DMA_IMSG_BALR_OFF                     0x050
#define MV_XOR_V2_DMA_IMSG_BAHR_OFF                     0x054
#define MV_XOR_V2_DMA_DESQ_CTRL_OFF                     0x100
#define   MV_XOR_V2_DMA_DESQ_CTRL_32B                   1
#define   MV_XOR_V2_DMA_DESQ_CTRL_128B                  7
#define MV_XOR_V2_DMA_DESQ_STOP_OFF                     0x800
#define MV_XOR_V2_DMA_DESQ_DEALLOC_OFF                  0x804
#define MV_XOR_V2_DMA_DESQ_ADD_OFF                      0x808
#define MV_XOR_V2_DMA_IMSG_TMOT                         0x810
#define   MV_XOR_V2_DMA_IMSG_TIMER_THRD_MASK            0x1FFF

/* XOR Global registers */
#define MV_XOR_V2_GLOB_BW_CTRL                          0x4
#define   MV_XOR_V2_GLOB_BW_CTRL_NUM_OSTD_RD_SHIFT      0
#define   MV_XOR_V2_GLOB_BW_CTRL_NUM_OSTD_RD_VAL        64
#define   MV_XOR_V2_GLOB_BW_CTRL_NUM_OSTD_WR_SHIFT      8
#define   MV_XOR_V2_GLOB_BW_CTRL_NUM_OSTD_WR_VAL        8
#define   MV_XOR_V2_GLOB_BW_CTRL_RD_BURST_LEN_SHIFT     12
#define   MV_XOR_V2_GLOB_BW_CTRL_RD_BURST_LEN_VAL       4
#define   MV_XOR_V2_GLOB_BW_CTRL_WR_BURST_LEN_SHIFT     16
#define   MV_XOR_V2_GLOB_BW_CTRL_WR_BURST_LEN_VAL       4
#define MV_XOR_V2_GLOB_PAUSE                            0x014
#define   MV_XOR_V2_GLOB_PAUSE_AXI_TIME_DIS_VAL         0x8
#define MV_XOR_V2_GLOB_SYS_INT_CAUSE                    0x200
#define MV_XOR_V2_GLOB_SYS_INT_MASK                     0x204
#define MV_XOR_V2_GLOB_MEM_INT_CAUSE                    0x220
#define MV_XOR_V2_GLOB_MEM_INT_MASK                     0x224

#define MV_XOR_V2_MIN_DESC_SIZE                         32
#define MV_XOR_V2_EXT_DESC_SIZE                         128

#define MV_XOR_V2_DESC_RESERVED_SIZE                    12
#define MV_XOR_V2_DESC_BUFF_D_ADDR_SIZE                 12

#define MV_XOR_V2_CMD_LINE_NUM_MAX_D_BUF                8

/*
 * Descriptors queue size. With 32 bytes descriptors, up to 2^14
 * descriptors are allowed, with 128 bytes descriptors, up to 2^12
 * descriptors are allowed. This driver uses 128 bytes descriptors,
 * but experimentation has shown that a set of 1024 descriptors is
 * sufficient to reach a good level of performance.
 */
#define MV_XOR_V2_DESC_NUM                              1024

/*
 * Threshold values for descriptors and timeout, determined by
 * experimentation as giving a good level of performance.
 */
#define MV_XOR_V2_DONE_IMSG_THRD  0x14
#define MV_XOR_V2_TIMER_THRD      0xB0

/**
 * struct mv_xor_v2_descriptor - DMA HW descriptor
 * @desc_id: used by S/W and is not affected by H/W.
 * @flags: error and status flags
 * @crc32_result: CRC32 calculation result
 * @desc_ctrl: operation mode and control flags
 * @buff_size: amount of bytes to be processed
 * @fill_pattern_src_addr: Fill-Pattern or Source-Address and
 * AW-Attributes
 * @data_buff_addr: Source (and might be RAID6 destination)
 * addresses of data buffers in RAID5 and RAID6
 * @reserved: reserved
 */
struct mv_xor_v2_descriptor {
        u16 desc_id;
        u16 flags;
        u32 crc32_result;
        u32 desc_ctrl;

        /* Definitions for desc_ctrl */
#define DESC_NUM_ACTIVE_D_BUF_SHIFT     22
#define DESC_OP_MODE_SHIFT              28
#define DESC_OP_MODE_NOP                0       /* Idle operation */
#define DESC_OP_MODE_MEMCPY             1       /* Pure-DMA operation */
#define DESC_OP_MODE_MEMSET             2       /* Mem-Fill operation */
#define DESC_OP_MODE_MEMINIT            3       /* Mem-Init operation */
#define DESC_OP_MODE_MEM_COMPARE        4       /* Mem-Compare operation */
#define DESC_OP_MODE_CRC32              5       /* CRC32 calculation */
#define DESC_OP_MODE_XOR                6       /* RAID5 (XOR) operation */
#define DESC_OP_MODE_RAID6              7       /* RAID6 P&Q-generation */
#define DESC_OP_MODE_RAID6_REC          8       /* RAID6 Recovery */
#define DESC_Q_BUFFER_ENABLE            BIT(16)
#define DESC_P_BUFFER_ENABLE            BIT(17)
#define DESC_IOD                        BIT(27)

        u32 buff_size;
        u32 fill_pattern_src_addr[4];
        u32 data_buff_addr[MV_XOR_V2_DESC_BUFF_D_ADDR_SIZE];
        u32 reserved[MV_XOR_V2_DESC_RESERVED_SIZE];
};

/**
 * struct mv_xor_v2_device - implements a xor device
 * @lock: lock for the engine
 * @clk: reference to the 'core' clock
 * @reg_clk: reference to the 'reg' clock
 * @dma_base: memory mapped DMA register base
 * @glob_base: memory mapped global register base
 * @irq_tasklet: tasklet used for IRQ handling call-backs
 * @free_sw_desc: linked list of free SW descriptors
 * @dmadev: dma device
 * @dmachan: dma channel
 * @hw_desq: HW descriptors queue
 * @hw_desq_virt: virtual address of DESCQ
 * @sw_desq: SW descriptors queue
 * @desc_size: HW descriptor size
 * @npendings: number of pending descriptors (for which tx_submit has
 * @hw_queue_idx: HW queue index
 * @irq: The Linux interrupt number
 * been called, but not yet issue_pending)
 */
struct mv_xor_v2_device {
        spinlock_t lock;
        void __iomem *dma_base;
        void __iomem *glob_base;
        struct clk *clk;
        struct clk *reg_clk;
        struct tasklet_struct irq_tasklet;
        struct list_head free_sw_desc;
        struct dma_device dmadev;
        struct dma_chan dmachan;
        dma_addr_t hw_desq;
        struct mv_xor_v2_descriptor *hw_desq_virt;
        struct mv_xor_v2_sw_desc *sw_desq;
        int desc_size;
        unsigned int npendings;
        unsigned int hw_queue_idx;
        unsigned int irq;
};

/**
 * struct mv_xor_v2_sw_desc - implements a xor SW descriptor
 * @idx: descriptor index
 * @async_tx: support for the async_tx api
 * @hw_desc: associated HW descriptor
 * @free_list: node of the free SW descriprots list
*/
struct mv_xor_v2_sw_desc {
        int idx;
        struct dma_async_tx_descriptor async_tx;
        struct mv_xor_v2_descriptor hw_desc;
        struct list_head free_list;
};

/*
 * Fill the data buffers to a HW descriptor
 */
static void mv_xor_v2_set_data_buffers(struct mv_xor_v2_device *xor_dev,
                                        struct mv_xor_v2_descriptor *desc,
                                        dma_addr_t src, int index)
{
        int arr_index = ((index >> 1) * 3);

        /*
         * Fill the buffer's addresses to the descriptor.
         *
         * The format of the buffers address for 2 sequential buffers
         * X and X + 1:
         *
         *  First word:  Buffer-DX-Address-Low[31:0]
         *  Second word: Buffer-DX+1-Address-Low[31:0]
         *  Third word:  DX+1-Buffer-Address-High[47:32] [31:16]
         *               DX-Buffer-Address-High[47:32] [15:0]
         */
        if ((index & 0x1) == 0) {
                desc->data_buff_addr[arr_index] = lower_32_bits(src);

                desc->data_buff_addr[arr_index + 2] &= ~0xFFFF;
                desc->data_buff_addr[arr_index + 2] |=
                        upper_32_bits(src) & 0xFFFF;
        } else {
                desc->data_buff_addr[arr_index + 1] =
                        lower_32_bits(src);

                desc->data_buff_addr[arr_index + 2] &= ~0xFFFF0000;
                desc->data_buff_addr[arr_index + 2] |=
                        (upper_32_bits(src) & 0xFFFF) << 16;
        }
}

/*
 * notify the engine of new descriptors, and update the available index.
 */
static void mv_xor_v2_add_desc_to_desq(struct mv_xor_v2_device *xor_dev,
                                       int num_of_desc)
{
        /* write the number of new descriptors in the DESQ. */
        writel(num_of_desc, xor_dev->dma_base + MV_XOR_V2_DMA_DESQ_ADD_OFF);
}

/*
 * free HW descriptors
 */
static void mv_xor_v2_free_desc_from_desq(struct mv_xor_v2_device *xor_dev,
                                          int num_of_desc)
{
        /* write the number of new descriptors in the DESQ. */
        writel(num_of_desc, xor_dev->dma_base + MV_XOR_V2_DMA_DESQ_DEALLOC_OFF);
}

/*
 * Set descriptor size
 * Return the HW descriptor size in bytes
 */
static int mv_xor_v2_set_desc_size(struct mv_xor_v2_device *xor_dev)
{
        writel(MV_XOR_V2_DMA_DESQ_CTRL_128B,
               xor_dev->dma_base + MV_XOR_V2_DMA_DESQ_CTRL_OFF);

        return MV_XOR_V2_EXT_DESC_SIZE;
}

/*
 * Set the IMSG threshold
 */
static inline
void mv_xor_v2_enable_imsg_thrd(struct mv_xor_v2_device *xor_dev)
{
        u32 reg;

        /* Configure threshold of number of descriptors, and enable timer */
        reg = readl(xor_dev->dma_base + MV_XOR_V2_DMA_IMSG_THRD_OFF);
        reg &= ~MV_XOR_V2_DMA_IMSG_THRD_MASK;
        reg |= MV_XOR_V2_DONE_IMSG_THRD;
        reg |= MV_XOR_V2_DMA_IMSG_TIMER_EN;
        writel(reg, xor_dev->dma_base + MV_XOR_V2_DMA_IMSG_THRD_OFF);

        /* Configure Timer Threshold */
        reg = readl(xor_dev->dma_base + MV_XOR_V2_DMA_IMSG_TMOT);
        reg &= ~MV_XOR_V2_DMA_IMSG_TIMER_THRD_MASK;
        reg |= MV_XOR_V2_TIMER_THRD;
        writel(reg, xor_dev->dma_base + MV_XOR_V2_DMA_IMSG_TMOT);
}

static irqreturn_t mv_xor_v2_interrupt_handler(int irq, void *data)
{
        struct mv_xor_v2_device *xor_dev = data;
        unsigned int ndescs;
        u32 reg;

        reg = readl(xor_dev->dma_base + MV_XOR_V2_DMA_DESQ_DONE_OFF);

        ndescs = ((reg >> MV_XOR_V2_DMA_DESQ_DONE_PENDING_SHIFT) &
                  MV_XOR_V2_DMA_DESQ_DONE_PENDING_MASK);

        /* No descriptors to process */
        if (!ndescs)
                return IRQ_NONE;

        /* schedule a tasklet to handle descriptors callbacks */
        tasklet_schedule(&xor_dev->irq_tasklet);

        return IRQ_HANDLED;
}

/*
 * submit a descriptor to the DMA engine
 */
static dma_cookie_t
mv_xor_v2_tx_submit(struct dma_async_tx_descriptor *tx)
{
        void *dest_hw_desc;
        dma_cookie_t cookie;
        struct mv_xor_v2_sw_desc *sw_desc =
                container_of(tx, struct mv_xor_v2_sw_desc, async_tx);
        struct mv_xor_v2_device *xor_dev =
                container_of(tx->chan, struct mv_xor_v2_device, dmachan);

        dev_dbg(xor_dev->dmadev.dev,
                "%s sw_desc %p: async_tx %p\n",
                __func__, sw_desc, &sw_desc->async_tx);

        /* assign cookie */
        spin_lock_bh(&xor_dev->lock);
        cookie = dma_cookie_assign(tx);

        /* copy the HW descriptor from the SW descriptor to the DESQ */
        dest_hw_desc = xor_dev->hw_desq_virt + xor_dev->hw_queue_idx;

        memcpy(dest_hw_desc, &sw_desc->hw_desc, xor_dev->desc_size);

        xor_dev->npendings++;
        xor_dev->hw_queue_idx++;
        if (xor_dev->hw_queue_idx >= MV_XOR_V2_DESC_NUM)
                xor_dev->hw_queue_idx = 0;

        spin_unlock_bh(&xor_dev->lock);

        return cookie;
}

/*
 * Prepare a SW descriptor
 */
static struct mv_xor_v2_sw_desc *
mv_xor_v2_prep_sw_desc(struct mv_xor_v2_device *xor_dev)
{
        struct mv_xor_v2_sw_desc *sw_desc;
        bool found = false;

        /* Lock the channel */
        spin_lock_bh(&xor_dev->lock);

        if (list_empty(&xor_dev->free_sw_desc)) {
                spin_unlock_bh(&xor_dev->lock);
                /* schedule tasklet to free some descriptors */
                tasklet_schedule(&xor_dev->irq_tasklet);
                return NULL;
        }

        list_for_each_entry(sw_desc, &xor_dev->free_sw_desc, free_list) {
                if (async_tx_test_ack(&sw_desc->async_tx)) {
                        found = true;
                        break;
                }
        }

        if (!found) {
                spin_unlock_bh(&xor_dev->lock);
                return NULL;
        }

        list_del(&sw_desc->free_list);

        /* Release the channel */
        spin_unlock_bh(&xor_dev->lock);

        return sw_desc;
}

/*
 * Prepare a HW descriptor for a memcpy operation
 */
static struct dma_async_tx_descriptor *
mv_xor_v2_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dest,
                          dma_addr_t src, size_t len, unsigned long flags)
{
        struct mv_xor_v2_sw_desc *sw_desc;
        struct mv_xor_v2_descriptor *hw_descriptor;
        struct mv_xor_v2_device *xor_dev;

        xor_dev = container_of(chan, struct mv_xor_v2_device, dmachan);

        dev_dbg(xor_dev->dmadev.dev,
                "%s len: %zu src %pad dest %pad flags: %ld\n",
                __func__, len, &src, &dest, flags);

        sw_desc = mv_xor_v2_prep_sw_desc(xor_dev);
        if (!sw_desc)
                return NULL;

        sw_desc->async_tx.flags = flags;

        /* set the HW descriptor */
        hw_descriptor = &sw_desc->hw_desc;

        /* save the SW descriptor ID to restore when operation is done */
        hw_descriptor->desc_id = sw_desc->idx;

        /* Set the MEMCPY control word */
        hw_descriptor->desc_ctrl =
                DESC_OP_MODE_MEMCPY << DESC_OP_MODE_SHIFT;

        if (flags & DMA_PREP_INTERRUPT)
                hw_descriptor->desc_ctrl |= DESC_IOD;

        /* Set source address */
        hw_descriptor->fill_pattern_src_addr[0] = lower_32_bits(src);
        hw_descriptor->fill_pattern_src_addr[1] =
                upper_32_bits(src) & 0xFFFF;

        /* Set Destination address */
        hw_descriptor->fill_pattern_src_addr[2] = lower_32_bits(dest);
        hw_descriptor->fill_pattern_src_addr[3] =
                upper_32_bits(dest) & 0xFFFF;

        /* Set buffers size */
        hw_descriptor->buff_size = len;

        /* return the async tx descriptor */
        return &sw_desc->async_tx;
}

/*
 * Prepare a HW descriptor for a XOR operation
 */
static struct dma_async_tx_descriptor *
mv_xor_v2_prep_dma_xor(struct dma_chan *chan, dma_addr_t dest, dma_addr_t *src,
                       unsigned int src_cnt, size_t len, unsigned long flags)
{
        struct mv_xor_v2_sw_desc *sw_desc;
        struct mv_xor_v2_descriptor *hw_descriptor;
        struct mv_xor_v2_device *xor_dev =
                container_of(chan, struct mv_xor_v2_device, dmachan);
        int i;

        if (src_cnt > MV_XOR_V2_CMD_LINE_NUM_MAX_D_BUF || src_cnt < 1)
                return NULL;

        dev_dbg(xor_dev->dmadev.dev,
                "%s src_cnt: %d len: %zu dest %pad flags: %ld\n",
                __func__, src_cnt, len, &dest, flags);

        sw_desc = mv_xor_v2_prep_sw_desc(xor_dev);
        if (!sw_desc)
                return NULL;

        sw_desc->async_tx.flags = flags;

        /* set the HW descriptor */
        hw_descriptor = &sw_desc->hw_desc;

        /* save the SW descriptor ID to restore when operation is done */
        hw_descriptor->desc_id = sw_desc->idx;

        /* Set the XOR control word */
        hw_descriptor->desc_ctrl =
                DESC_OP_MODE_XOR << DESC_OP_MODE_SHIFT;
        hw_descriptor->desc_ctrl |= DESC_P_BUFFER_ENABLE;

        if (flags & DMA_PREP_INTERRUPT)
                hw_descriptor->desc_ctrl |= DESC_IOD;

        /* Set the data buffers */
        for (i = 0; i < src_cnt; i++)
                mv_xor_v2_set_data_buffers(xor_dev, hw_descriptor, src[i], i);

        hw_descriptor->desc_ctrl |=
                src_cnt << DESC_NUM_ACTIVE_D_BUF_SHIFT;

        /* Set Destination address */
        hw_descriptor->fill_pattern_src_addr[2] = lower_32_bits(dest);
        hw_descriptor->fill_pattern_src_addr[3] =
                upper_32_bits(dest) & 0xFFFF;

        /* Set buffers size */
        hw_descriptor->buff_size = len;

        /* return the async tx descriptor */
        return &sw_desc->async_tx;
}

/*
 * Prepare a HW descriptor for interrupt operation.
 */
static struct dma_async_tx_descriptor *
mv_xor_v2_prep_dma_interrupt(struct dma_chan *chan, unsigned long flags)
{
        struct mv_xor_v2_sw_desc *sw_desc;
        struct mv_xor_v2_descriptor *hw_descriptor;
        struct mv_xor_v2_device *xor_dev =
                container_of(chan, struct mv_xor_v2_device, dmachan);

        sw_desc = mv_xor_v2_prep_sw_desc(xor_dev);
        if (!sw_desc)
                return NULL;

        /* set the HW descriptor */
        hw_descriptor = &sw_desc->hw_desc;

        /* save the SW descriptor ID to restore when operation is done */
        hw_descriptor->desc_id = sw_desc->idx;

        /* Set the INTERRUPT control word */
        hw_descriptor->desc_ctrl =
                DESC_OP_MODE_NOP << DESC_OP_MODE_SHIFT;
        hw_descriptor->desc_ctrl |= DESC_IOD;

        /* return the async tx descriptor */
        return &sw_desc->async_tx;
}

/*
 * push pending transactions to hardware
 */
static void mv_xor_v2_issue_pending(struct dma_chan *chan)
{
        struct mv_xor_v2_device *xor_dev =
                container_of(chan, struct mv_xor_v2_device, dmachan);

        spin_lock_bh(&xor_dev->lock);

        /*
         * update the engine with the number of descriptors to
         * process
         */
        mv_xor_v2_add_desc_to_desq(xor_dev, xor_dev->npendings);
        xor_dev->npendings = 0;

        spin_unlock_bh(&xor_dev->lock);
}

static inline
int mv_xor_v2_get_pending_params(struct mv_xor_v2_device *xor_dev,
                                 int *pending_ptr)
{
        u32 reg;

        reg = readl(xor_dev->dma_base + MV_XOR_V2_DMA_DESQ_DONE_OFF);

        /* get the next pending descriptor index */
        *pending_ptr = ((reg >> MV_XOR_V2_DMA_DESQ_DONE_READ_PTR_SHIFT) &
                        MV_XOR_V2_DMA_DESQ_DONE_READ_PTR_MASK);

        /* get the number of descriptors pending handle */
        return ((reg >> MV_XOR_V2_DMA_DESQ_DONE_PENDING_SHIFT) &
                MV_XOR_V2_DMA_DESQ_DONE_PENDING_MASK);
}

/*
 * handle the descriptors after HW process
 */
static void mv_xor_v2_tasklet(struct tasklet_struct *t)
{
        struct mv_xor_v2_device *xor_dev = from_tasklet(xor_dev, t,
                                                        irq_tasklet);
        int pending_ptr, num_of_pending, i;
        struct mv_xor_v2_sw_desc *next_pending_sw_desc = NULL;

        dev_dbg(xor_dev->dmadev.dev, "%s %d\n", __func__, __LINE__);

        /* get the pending descriptors parameters */
        num_of_pending = mv_xor_v2_get_pending_params(xor_dev, &pending_ptr);

        /* loop over free descriptors */
        for (i = 0; i < num_of_pending; i++) {
                struct mv_xor_v2_descriptor *next_pending_hw_desc =
                        xor_dev->hw_desq_virt + pending_ptr;

                /* get the SW descriptor related to the HW descriptor */
                next_pending_sw_desc =
                        &xor_dev->sw_desq[next_pending_hw_desc->desc_id];

                /* call the callback */
                if (next_pending_sw_desc->async_tx.cookie > 0) {
                        /*
                         * update the channel's completed cookie - no
                         * lock is required the IMSG threshold provide
                         * the locking
                         */
                        dma_cookie_complete(&next_pending_sw_desc->async_tx);

                        dma_descriptor_unmap(&next_pending_sw_desc->async_tx);
                        dmaengine_desc_get_callback_invoke(
                                        &next_pending_sw_desc->async_tx, NULL);
                }

                dma_run_dependencies(&next_pending_sw_desc->async_tx);

                /* Lock the channel */
                spin_lock(&xor_dev->lock);

                /* add the SW descriptor to the free descriptors list */
                list_add(&next_pending_sw_desc->free_list,
                         &xor_dev->free_sw_desc);

                /* Release the channel */
                spin_unlock(&xor_dev->lock);

                /* increment the next descriptor */
                pending_ptr++;
                if (pending_ptr >= MV_XOR_V2_DESC_NUM)
                        pending_ptr = 0;
        }

        if (num_of_pending != 0) {
                /* free the descriptores */
                mv_xor_v2_free_desc_from_desq(xor_dev, num_of_pending);
        }
}

/*
 *      Set DMA Interrupt-message (IMSG) parameters
 */
static void mv_xor_v2_set_msi_msg(struct msi_desc *desc, struct msi_msg *msg)
{
        struct mv_xor_v2_device *xor_dev = dev_get_drvdata(desc->dev);

        writel(msg->address_lo,
               xor_dev->dma_base + MV_XOR_V2_DMA_IMSG_BALR_OFF);
        writel(msg->address_hi & 0xFFFF,
               xor_dev->dma_base + MV_XOR_V2_DMA_IMSG_BAHR_OFF);
        writel(msg->data,
               xor_dev->dma_base + MV_XOR_V2_DMA_IMSG_CDAT_OFF);
}

static int mv_xor_v2_descq_init(struct mv_xor_v2_device *xor_dev)
{
        u32 reg;

        /* write the DESQ size to the DMA engine */
        writel(MV_XOR_V2_DESC_NUM,
               xor_dev->dma_base + MV_XOR_V2_DMA_DESQ_SIZE_OFF);

        /* write the DESQ address to the DMA engine*/
        writel(lower_32_bits(xor_dev->hw_desq),
               xor_dev->dma_base + MV_XOR_V2_DMA_DESQ_BALR_OFF);
        writel(upper_32_bits(xor_dev->hw_desq),
               xor_dev->dma_base + MV_XOR_V2_DMA_DESQ_BAHR_OFF);

        /*
         * This is a temporary solution, until we activate the
         * SMMU. Set the attributes for reading & writing data buffers
         * & descriptors to:
         *
         *  - OuterShareable - Snoops will be performed on CPU caches
         *  - Enable cacheable - Bufferable, Modifiable, Other Allocate
         *    and Allocate
         */
        reg = readl(xor_dev->dma_base + MV_XOR_V2_DMA_DESQ_ARATTR_OFF);
        reg &= ~MV_XOR_V2_DMA_DESQ_ATTR_CACHE_MASK;
        reg |= MV_XOR_V2_DMA_DESQ_ATTR_OUTER_SHAREABLE |
                MV_XOR_V2_DMA_DESQ_ATTR_CACHEABLE;
        writel(reg, xor_dev->dma_base + MV_XOR_V2_DMA_DESQ_ARATTR_OFF);

        reg = readl(xor_dev->dma_base + MV_XOR_V2_DMA_DESQ_AWATTR_OFF);
        reg &= ~MV_XOR_V2_DMA_DESQ_ATTR_CACHE_MASK;
        reg |= MV_XOR_V2_DMA_DESQ_ATTR_OUTER_SHAREABLE |
                MV_XOR_V2_DMA_DESQ_ATTR_CACHEABLE;
        writel(reg, xor_dev->dma_base + MV_XOR_V2_DMA_DESQ_AWATTR_OFF);

        /* BW CTRL - set values to optimize the XOR performance:
         *
         *  - Set WrBurstLen & RdBurstLen - the unit will issue
         *    maximum of 256B write/read transactions.
         * -  Limit the number of outstanding write & read data
         *    (OBB/IBB) requests to the maximal value.
        */
        reg = ((MV_XOR_V2_GLOB_BW_CTRL_NUM_OSTD_RD_VAL <<
                MV_XOR_V2_GLOB_BW_CTRL_NUM_OSTD_RD_SHIFT) |
               (MV_XOR_V2_GLOB_BW_CTRL_NUM_OSTD_WR_VAL  <<
                MV_XOR_V2_GLOB_BW_CTRL_NUM_OSTD_WR_SHIFT) |
               (MV_XOR_V2_GLOB_BW_CTRL_RD_BURST_LEN_VAL <<
                MV_XOR_V2_GLOB_BW_CTRL_RD_BURST_LEN_SHIFT) |
               (MV_XOR_V2_GLOB_BW_CTRL_WR_BURST_LEN_VAL <<
                MV_XOR_V2_GLOB_BW_CTRL_WR_BURST_LEN_SHIFT));
        writel(reg, xor_dev->glob_base + MV_XOR_V2_GLOB_BW_CTRL);

        /* Disable the AXI timer feature */
        reg = readl(xor_dev->glob_base + MV_XOR_V2_GLOB_PAUSE);
        reg |= MV_XOR_V2_GLOB_PAUSE_AXI_TIME_DIS_VAL;
        writel(reg, xor_dev->glob_base + MV_XOR_V2_GLOB_PAUSE);

        /* enable the DMA engine */
        writel(0, xor_dev->dma_base + MV_XOR_V2_DMA_DESQ_STOP_OFF);

        return 0;
}

static int mv_xor_v2_suspend(struct platform_device *dev, pm_message_t state)
{
        struct mv_xor_v2_device *xor_dev = platform_get_drvdata(dev);

        /* Set this bit to disable to stop the XOR unit. */
        writel(0x1, xor_dev->dma_base + MV_XOR_V2_DMA_DESQ_STOP_OFF);

        return 0;
}

static int mv_xor_v2_resume(struct platform_device *dev)
{
        struct mv_xor_v2_device *xor_dev = platform_get_drvdata(dev);

        mv_xor_v2_set_desc_size(xor_dev);
        mv_xor_v2_enable_imsg_thrd(xor_dev);
        mv_xor_v2_descq_init(xor_dev);

        return 0;
}

static int mv_xor_v2_probe(struct platform_device *pdev)
{
        struct mv_xor_v2_device *xor_dev;
        int i, ret = 0;
        struct dma_device *dma_dev;
        struct mv_xor_v2_sw_desc *sw_desc;

        BUILD_BUG_ON(sizeof(struct mv_xor_v2_descriptor) !=
                     MV_XOR_V2_EXT_DESC_SIZE);

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

        xor_dev->dma_base = devm_platform_ioremap_resource(pdev, 0);
        if (IS_ERR(xor_dev->dma_base))
                return PTR_ERR(xor_dev->dma_base);

        xor_dev->glob_base = devm_platform_ioremap_resource(pdev, 1);
        if (IS_ERR(xor_dev->glob_base))
                return PTR_ERR(xor_dev->glob_base);

        platform_set_drvdata(pdev, xor_dev);

        ret = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(40));
        if (ret)
                return ret;

        xor_dev->reg_clk = devm_clk_get_optional_enabled(&pdev->dev, "reg");
        if (IS_ERR(xor_dev->reg_clk))
                return PTR_ERR(xor_dev->reg_clk);

        xor_dev->clk = devm_clk_get_enabled(&pdev->dev, NULL);
        if (IS_ERR(xor_dev->clk))
                return PTR_ERR(xor_dev->clk);

        ret = platform_device_msi_init_and_alloc_irqs(&pdev->dev, 1,
                                                      mv_xor_v2_set_msi_msg);
        if (ret)
                return ret;

        xor_dev->irq = msi_get_virq(&pdev->dev, 0);

        ret = devm_request_irq(&pdev->dev, xor_dev->irq,
                               mv_xor_v2_interrupt_handler, 0,
                               dev_name(&pdev->dev), xor_dev);
        if (ret)
                goto free_msi_irqs;

        tasklet_setup(&xor_dev->irq_tasklet, mv_xor_v2_tasklet);

        xor_dev->desc_size = mv_xor_v2_set_desc_size(xor_dev);

        dma_cookie_init(&xor_dev->dmachan);

        /*
         * allocate coherent memory for hardware descriptors
         * note: writecombine gives slightly better performance, but
         * requires that we explicitly flush the writes
         */
        xor_dev->hw_desq_virt =
                dma_alloc_coherent(&pdev->dev,
                                   xor_dev->desc_size * MV_XOR_V2_DESC_NUM,
                                   &xor_dev->hw_desq, GFP_KERNEL);
        if (!xor_dev->hw_desq_virt) {
                ret = -ENOMEM;
                goto free_msi_irqs;
        }

        /* alloc memory for the SW descriptors */
        xor_dev->sw_desq = devm_kcalloc(&pdev->dev,
                                        MV_XOR_V2_DESC_NUM, sizeof(*sw_desc),
                                        GFP_KERNEL);
        if (!xor_dev->sw_desq) {
                ret = -ENOMEM;
                goto free_hw_desq;
        }

        spin_lock_init(&xor_dev->lock);

        /* init the free SW descriptors list */
        INIT_LIST_HEAD(&xor_dev->free_sw_desc);

        /* add all SW descriptors to the free list */
        for (i = 0; i < MV_XOR_V2_DESC_NUM; i++) {
                struct mv_xor_v2_sw_desc *sw_desc =
                        xor_dev->sw_desq + i;
                sw_desc->idx = i;
                dma_async_tx_descriptor_init(&sw_desc->async_tx,
                                             &xor_dev->dmachan);
                sw_desc->async_tx.tx_submit = mv_xor_v2_tx_submit;
                async_tx_ack(&sw_desc->async_tx);

                list_add(&sw_desc->free_list,
                         &xor_dev->free_sw_desc);
        }

        dma_dev = &xor_dev->dmadev;

        /* set DMA capabilities */
        dma_cap_zero(dma_dev->cap_mask);
        dma_cap_set(DMA_MEMCPY, dma_dev->cap_mask);
        dma_cap_set(DMA_XOR, dma_dev->cap_mask);
        dma_cap_set(DMA_INTERRUPT, dma_dev->cap_mask);

        /* init dma link list */
        INIT_LIST_HEAD(&dma_dev->channels);

        /* set base routines */
        dma_dev->device_tx_status = dma_cookie_status;
        dma_dev->device_issue_pending = mv_xor_v2_issue_pending;
        dma_dev->dev = &pdev->dev;

        dma_dev->device_prep_dma_memcpy = mv_xor_v2_prep_dma_memcpy;
        dma_dev->device_prep_dma_interrupt = mv_xor_v2_prep_dma_interrupt;
        dma_dev->max_xor = 8;
        dma_dev->device_prep_dma_xor = mv_xor_v2_prep_dma_xor;

        xor_dev->dmachan.device = dma_dev;

        list_add_tail(&xor_dev->dmachan.device_node,
                      &dma_dev->channels);

        mv_xor_v2_enable_imsg_thrd(xor_dev);

        mv_xor_v2_descq_init(xor_dev);

        ret = dma_async_device_register(dma_dev);
        if (ret)
                goto free_hw_desq;

        dev_notice(&pdev->dev, "Marvell Version 2 XOR driver\n");

        return 0;

free_hw_desq:
        dma_free_coherent(&pdev->dev,
                          xor_dev->desc_size * MV_XOR_V2_DESC_NUM,
                          xor_dev->hw_desq_virt, xor_dev->hw_desq);
free_msi_irqs:
        platform_device_msi_free_irqs_all(&pdev->dev);
        return ret;
}

static void mv_xor_v2_remove(struct platform_device *pdev)
{
        struct mv_xor_v2_device *xor_dev = platform_get_drvdata(pdev);

        dma_async_device_unregister(&xor_dev->dmadev);

        dma_free_coherent(&pdev->dev,
                          xor_dev->desc_size * MV_XOR_V2_DESC_NUM,
                          xor_dev->hw_desq_virt, xor_dev->hw_desq);

        devm_free_irq(&pdev->dev, xor_dev->irq, xor_dev);

        platform_device_msi_free_irqs_all(&pdev->dev);

        tasklet_kill(&xor_dev->irq_tasklet);
}

#ifdef CONFIG_OF
static const struct of_device_id mv_xor_v2_dt_ids[] = {
        { .compatible = "marvell,xor-v2", },
        {},
};
MODULE_DEVICE_TABLE(of, mv_xor_v2_dt_ids);
#endif

static struct platform_driver mv_xor_v2_driver = {
        .probe          = mv_xor_v2_probe,
        .suspend        = mv_xor_v2_suspend,
        .resume         = mv_xor_v2_resume,
        .remove         = mv_xor_v2_remove,
        .driver         = {
                .name   = "mv_xor_v2",
                .of_match_table = of_match_ptr(mv_xor_v2_dt_ids),
        },
};

module_platform_driver(mv_xor_v2_driver);

MODULE_DESCRIPTION("DMA engine driver for Marvell's Version 2 of XOR engine");