// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Applied Micro X-Gene SoC DMA engine Driver
 *
 * Copyright (c) 2015, Applied Micro Circuits Corporation
 * Authors: Rameshwar Prasad Sahu <rsahu@apm.com>
 *          Loc Ho <lho@apm.com>
 *
 * NOTE: PM support is currently not available.
 */

#include <linux/acpi.h>
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/dma-mapping.h>
#include <linux/dmaengine.h>
#include <linux/dmapool.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/irq.h>
#include <linux/module.h>
#include <linux/of_device.h>

#include "dmaengine.h"

/* X-Gene DMA ring csr registers and bit definations */
#define XGENE_DMA_RING_CONFIG                   0x04
#define XGENE_DMA_RING_ENABLE                   BIT(31)
#define XGENE_DMA_RING_ID                       0x08
#define XGENE_DMA_RING_ID_SETUP(v)              ((v) | BIT(31))
#define XGENE_DMA_RING_ID_BUF                   0x0C
#define XGENE_DMA_RING_ID_BUF_SETUP(v)          (((v) << 9) | BIT(21))
#define XGENE_DMA_RING_THRESLD0_SET1            0x30
#define XGENE_DMA_RING_THRESLD0_SET1_VAL        0X64
#define XGENE_DMA_RING_THRESLD1_SET1            0x34
#define XGENE_DMA_RING_THRESLD1_SET1_VAL        0xC8
#define XGENE_DMA_RING_HYSTERESIS               0x68
#define XGENE_DMA_RING_HYSTERESIS_VAL           0xFFFFFFFF
#define XGENE_DMA_RING_STATE                    0x6C
#define XGENE_DMA_RING_STATE_WR_BASE            0x70
#define XGENE_DMA_RING_NE_INT_MODE              0x017C
#define XGENE_DMA_RING_NE_INT_MODE_SET(m, v)    \
        ((m) = ((m) & ~BIT(31 - (v))) | BIT(31 - (v)))
#define XGENE_DMA_RING_NE_INT_MODE_RESET(m, v)  \
        ((m) &= (~BIT(31 - (v))))
#define XGENE_DMA_RING_CLKEN                    0xC208
#define XGENE_DMA_RING_SRST                     0xC200
#define XGENE_DMA_RING_MEM_RAM_SHUTDOWN         0xD070
#define XGENE_DMA_RING_BLK_MEM_RDY              0xD074
#define XGENE_DMA_RING_BLK_MEM_RDY_VAL          0xFFFFFFFF
#define XGENE_DMA_RING_ID_GET(owner, num)       (((owner) << 6) | (num))
#define XGENE_DMA_RING_DST_ID(v)                ((1 << 10) | (v))
#define XGENE_DMA_RING_CMD_OFFSET               0x2C
#define XGENE_DMA_RING_CMD_BASE_OFFSET(v)       ((v) << 6)
#define XGENE_DMA_RING_COHERENT_SET(m)          \
        (((u32 *)(m))[2] |= BIT(4))
#define XGENE_DMA_RING_ADDRL_SET(m, v)          \
        (((u32 *)(m))[2] |= (((v) >> 8) << 5))
#define XGENE_DMA_RING_ADDRH_SET(m, v)          \
        (((u32 *)(m))[3] |= ((v) >> 35))
#define XGENE_DMA_RING_ACCEPTLERR_SET(m)        \
        (((u32 *)(m))[3] |= BIT(19))
#define XGENE_DMA_RING_SIZE_SET(m, v)           \
        (((u32 *)(m))[3] |= ((v) << 23))
#define XGENE_DMA_RING_RECOMBBUF_SET(m)         \
        (((u32 *)(m))[3] |= BIT(27))
#define XGENE_DMA_RING_RECOMTIMEOUTL_SET(m)     \
        (((u32 *)(m))[3] |= (0x7 << 28))
#define XGENE_DMA_RING_RECOMTIMEOUTH_SET(m)     \
        (((u32 *)(m))[4] |= 0x3)
#define XGENE_DMA_RING_SELTHRSH_SET(m)          \
        (((u32 *)(m))[4] |= BIT(3))
#define XGENE_DMA_RING_TYPE_SET(m, v)           \
        (((u32 *)(m))[4] |= ((v) << 19))

/* X-Gene DMA device csr registers and bit definitions */
#define XGENE_DMA_IPBRR                         0x0
#define XGENE_DMA_DEV_ID_RD(v)                  ((v) & 0x00000FFF)
#define XGENE_DMA_BUS_ID_RD(v)                  (((v) >> 12) & 3)
#define XGENE_DMA_REV_NO_RD(v)                  (((v) >> 14) & 3)
#define XGENE_DMA_GCR                           0x10
#define XGENE_DMA_CH_SETUP(v)                   \
        ((v) = ((v) & ~0x000FFFFF) | 0x000AAFFF)
#define XGENE_DMA_ENABLE(v)                     ((v) |= BIT(31))
#define XGENE_DMA_DISABLE(v)                    ((v) &= ~BIT(31))
#define XGENE_DMA_RAID6_CONT                    0x14
#define XGENE_DMA_RAID6_MULTI_CTRL(v)           ((v) << 24)
#define XGENE_DMA_INT                           0x70
#define XGENE_DMA_INT_MASK                      0x74
#define XGENE_DMA_INT_ALL_MASK                  0xFFFFFFFF
#define XGENE_DMA_INT_ALL_UNMASK                0x0
#define XGENE_DMA_INT_MASK_SHIFT                0x14
#define XGENE_DMA_RING_INT0_MASK                0x90A0
#define XGENE_DMA_RING_INT1_MASK                0x90A8
#define XGENE_DMA_RING_INT2_MASK                0x90B0
#define XGENE_DMA_RING_INT3_MASK                0x90B8
#define XGENE_DMA_RING_INT4_MASK                0x90C0
#define XGENE_DMA_CFG_RING_WQ_ASSOC             0x90E0
#define XGENE_DMA_ASSOC_RING_MNGR1              0xFFFFFFFF
#define XGENE_DMA_MEM_RAM_SHUTDOWN              0xD070
#define XGENE_DMA_BLK_MEM_RDY                   0xD074
#define XGENE_DMA_BLK_MEM_RDY_VAL               0xFFFFFFFF
#define XGENE_DMA_RING_CMD_SM_OFFSET            0x8000

/* X-Gene SoC EFUSE csr register and bit defination */
#define XGENE_SOC_JTAG1_SHADOW                  0x18
#define XGENE_DMA_PQ_DISABLE_MASK               BIT(13)

/* X-Gene DMA Descriptor format */
#define XGENE_DMA_DESC_NV_BIT                   BIT_ULL(50)
#define XGENE_DMA_DESC_IN_BIT                   BIT_ULL(55)
#define XGENE_DMA_DESC_C_BIT                    BIT_ULL(63)
#define XGENE_DMA_DESC_DR_BIT                   BIT_ULL(61)
#define XGENE_DMA_DESC_ELERR_POS                46
#define XGENE_DMA_DESC_RTYPE_POS                56
#define XGENE_DMA_DESC_LERR_POS                 60
#define XGENE_DMA_DESC_BUFLEN_POS               48
#define XGENE_DMA_DESC_HOENQ_NUM_POS            48
#define XGENE_DMA_DESC_ELERR_RD(m)              \
        (((m) >> XGENE_DMA_DESC_ELERR_POS) & 0x3)
#define XGENE_DMA_DESC_LERR_RD(m)               \
        (((m) >> XGENE_DMA_DESC_LERR_POS) & 0x7)
#define XGENE_DMA_DESC_STATUS(elerr, lerr)      \
        (((elerr) << 4) | (lerr))

/* X-Gene DMA descriptor empty s/w signature */
#define XGENE_DMA_DESC_EMPTY_SIGNATURE          ~0ULL

/* X-Gene DMA configurable parameters defines */
#define XGENE_DMA_RING_NUM              512
#define XGENE_DMA_BUFNUM                0x0
#define XGENE_DMA_CPU_BUFNUM            0x18
#define XGENE_DMA_RING_OWNER_DMA        0x03
#define XGENE_DMA_RING_OWNER_CPU        0x0F
#define XGENE_DMA_RING_TYPE_REGULAR     0x01
#define XGENE_DMA_RING_WQ_DESC_SIZE     32      /* 32 Bytes */
#define XGENE_DMA_RING_NUM_CONFIG       5
#define XGENE_DMA_MAX_CHANNEL           4
#define XGENE_DMA_XOR_CHANNEL           0
#define XGENE_DMA_PQ_CHANNEL            1
#define XGENE_DMA_MAX_BYTE_CNT          0x4000  /* 16 KB */
#define XGENE_DMA_MAX_64B_DESC_BYTE_CNT 0x14000 /* 80 KB */
#define XGENE_DMA_MAX_XOR_SRC           5
#define XGENE_DMA_16K_BUFFER_LEN_CODE   0x0
#define XGENE_DMA_INVALID_LEN_CODE      0x7800000000000000ULL

/* X-Gene DMA descriptor error codes */
#define ERR_DESC_AXI                    0x01
#define ERR_BAD_DESC                    0x02
#define ERR_READ_DATA_AXI               0x03
#define ERR_WRITE_DATA_AXI              0x04
#define ERR_FBP_TIMEOUT                 0x05
#define ERR_ECC                         0x06
#define ERR_DIFF_SIZE                   0x08
#define ERR_SCT_GAT_LEN                 0x09
#define ERR_CRC_ERR                     0x11
#define ERR_CHKSUM                      0x12
#define ERR_DIF                         0x13

/* X-Gene DMA error interrupt codes */
#define ERR_DIF_SIZE_INT                0x0
#define ERR_GS_ERR_INT                  0x1
#define ERR_FPB_TIMEO_INT               0x2
#define ERR_WFIFO_OVF_INT               0x3
#define ERR_RFIFO_OVF_INT               0x4
#define ERR_WR_TIMEO_INT                0x5
#define ERR_RD_TIMEO_INT                0x6
#define ERR_WR_ERR_INT                  0x7
#define ERR_RD_ERR_INT                  0x8
#define ERR_BAD_DESC_INT                0x9
#define ERR_DESC_DST_INT                0xA
#define ERR_DESC_SRC_INT                0xB

/* X-Gene DMA flyby operation code */
#define FLYBY_2SRC_XOR                  0x80
#define FLYBY_3SRC_XOR                  0x90
#define FLYBY_4SRC_XOR                  0xA0
#define FLYBY_5SRC_XOR                  0xB0

/* X-Gene DMA SW descriptor flags */
#define XGENE_DMA_FLAG_64B_DESC         BIT(0)

/* Define to dump X-Gene DMA descriptor */
#define XGENE_DMA_DESC_DUMP(desc, m)    \
        print_hex_dump(KERN_ERR, (m),   \
                        DUMP_PREFIX_ADDRESS, 16, 8, (desc), 32, 0)

#define to_dma_desc_sw(tx)              \
        container_of(tx, struct xgene_dma_desc_sw, tx)
#define to_dma_chan(dchan)              \
        container_of(dchan, struct xgene_dma_chan, dma_chan)

#define chan_dbg(chan, fmt, arg...)     \
        dev_dbg(chan->dev, "%s: " fmt, chan->name, ##arg)
#define chan_err(chan, fmt, arg...)     \
        dev_err(chan->dev, "%s: " fmt, chan->name, ##arg)

struct xgene_dma_desc_hw {
        __le64 m0;
        __le64 m1;
        __le64 m2;
        __le64 m3;
};

enum xgene_dma_ring_cfgsize {
        XGENE_DMA_RING_CFG_SIZE_512B,
        XGENE_DMA_RING_CFG_SIZE_2KB,
        XGENE_DMA_RING_CFG_SIZE_16KB,
        XGENE_DMA_RING_CFG_SIZE_64KB,
        XGENE_DMA_RING_CFG_SIZE_512KB,
        XGENE_DMA_RING_CFG_SIZE_INVALID
};

struct xgene_dma_ring {
        struct xgene_dma *pdma;
        u8 buf_num;
        u16 id;
        u16 num;
        u16 head;
        u16 owner;
        u16 slots;
        u16 dst_ring_num;
        u32 size;
        void __iomem *cmd;
        void __iomem *cmd_base;
        dma_addr_t desc_paddr;
        u32 state[XGENE_DMA_RING_NUM_CONFIG];
        enum xgene_dma_ring_cfgsize cfgsize;
        union {
                void *desc_vaddr;
                struct xgene_dma_desc_hw *desc_hw;
        };
};

struct xgene_dma_desc_sw {
        struct xgene_dma_desc_hw desc1;
        struct xgene_dma_desc_hw desc2;
        u32 flags;
        struct list_head node;
        struct list_head tx_list;
        struct dma_async_tx_descriptor tx;
};

/**
 * struct xgene_dma_chan - internal representation of an X-Gene DMA channel
 * @dma_chan: dmaengine channel object member
 * @pdma: X-Gene DMA device structure reference
 * @dev: struct device reference for dma mapping api
 * @id: raw id of this channel
 * @rx_irq: channel IRQ
 * @name: name of X-Gene DMA channel
 * @lock: serializes enqueue/dequeue operations to the descriptor pool
 * @pending: number of transaction request pushed to DMA controller for
 *      execution, but still waiting for completion,
 * @max_outstanding: max number of outstanding request we can push to channel
 * @ld_pending: descriptors which are queued to run, but have not yet been
 *      submitted to the hardware for execution
 * @ld_running: descriptors which are currently being executing by the hardware
 * @ld_completed: descriptors which have finished execution by the hardware.
 *      These descriptors have already had their cleanup actions run. They
 *      are waiting for the ACK bit to be set by the async tx API.
 * @desc_pool: descriptor pool for DMA operations
 * @tasklet: bottom half where all completed descriptors cleans
 * @tx_ring: transmit ring descriptor that we use to prepare actual
 *      descriptors for further executions
 * @rx_ring: receive ring descriptor that we use to get completed DMA
 *      descriptors during cleanup time
 */
struct xgene_dma_chan {
        struct dma_chan dma_chan;
        struct xgene_dma *pdma;
        struct device *dev;
        int id;
        int rx_irq;
        char name[10];
        spinlock_t lock;
        int pending;
        int max_outstanding;
        struct list_head ld_pending;
        struct list_head ld_running;
        struct list_head ld_completed;
        struct dma_pool *desc_pool;
        struct tasklet_struct tasklet;
        struct xgene_dma_ring tx_ring;
        struct xgene_dma_ring rx_ring;
};

/**
 * struct xgene_dma - internal representation of an X-Gene DMA device
 * @dev: reference to this device's struct device
 * @clk: reference to this device's clock
 * @err_irq: DMA error irq number
 * @ring_num: start id number for DMA ring
 * @csr_dma: base for DMA register access
 * @csr_ring: base for DMA ring register access
 * @csr_ring_cmd: base for DMA ring command register access
 * @csr_efuse: base for efuse register access
 * @dma_dev: embedded struct dma_device
 * @chan: reference to X-Gene DMA channels
 */
struct xgene_dma {
        struct device *dev;
        struct clk *clk;
        int err_irq;
        int ring_num;
        void __iomem *csr_dma;
        void __iomem *csr_ring;
        void __iomem *csr_ring_cmd;
        void __iomem *csr_efuse;
        struct dma_device dma_dev[XGENE_DMA_MAX_CHANNEL];
        struct xgene_dma_chan chan[XGENE_DMA_MAX_CHANNEL];
};

static const char * const xgene_dma_desc_err[] = {
        [ERR_DESC_AXI] = "AXI error when reading src/dst link list",
        [ERR_BAD_DESC] = "ERR or El_ERR fields not set to zero in desc",
        [ERR_READ_DATA_AXI] = "AXI error when reading data",
        [ERR_WRITE_DATA_AXI] = "AXI error when writing data",
        [ERR_FBP_TIMEOUT] = "Timeout on bufpool fetch",
        [ERR_ECC] = "ECC double bit error",
        [ERR_DIFF_SIZE] = "Bufpool too small to hold all the DIF result",
        [ERR_SCT_GAT_LEN] = "Gather and scatter data length not same",
        [ERR_CRC_ERR] = "CRC error",
        [ERR_CHKSUM] = "Checksum error",
        [ERR_DIF] = "DIF error",
};

static const char * const xgene_dma_err[] = {
        [ERR_DIF_SIZE_INT] = "DIF size error",
        [ERR_GS_ERR_INT] = "Gather scatter not same size error",
        [ERR_FPB_TIMEO_INT] = "Free pool time out error",
        [ERR_WFIFO_OVF_INT] = "Write FIFO over flow error",
        [ERR_RFIFO_OVF_INT] = "Read FIFO over flow error",
        [ERR_WR_TIMEO_INT] = "Write time out error",
        [ERR_RD_TIMEO_INT] = "Read time out error",
        [ERR_WR_ERR_INT] = "HBF bus write error",
        [ERR_RD_ERR_INT] = "HBF bus read error",
        [ERR_BAD_DESC_INT] = "Ring descriptor HE0 not set error",
        [ERR_DESC_DST_INT] = "HFB reading dst link address error",
        [ERR_DESC_SRC_INT] = "HFB reading src link address error",
};

static bool is_pq_enabled(struct xgene_dma *pdma)
{
        u32 val;

        val = ioread32(pdma->csr_efuse + XGENE_SOC_JTAG1_SHADOW);
        return !(val & XGENE_DMA_PQ_DISABLE_MASK);
}

static u64 xgene_dma_encode_len(size_t len)
{
        return (len < XGENE_DMA_MAX_BYTE_CNT) ?
                ((u64)len << XGENE_DMA_DESC_BUFLEN_POS) :
                XGENE_DMA_16K_BUFFER_LEN_CODE;
}

static u8 xgene_dma_encode_xor_flyby(u32 src_cnt)
{
        static u8 flyby_type[] = {
                FLYBY_2SRC_XOR, /* Dummy */
                FLYBY_2SRC_XOR, /* Dummy */
                FLYBY_2SRC_XOR,
                FLYBY_3SRC_XOR,
                FLYBY_4SRC_XOR,
                FLYBY_5SRC_XOR
        };

        return flyby_type[src_cnt];
}

static void xgene_dma_set_src_buffer(__le64 *ext8, size_t *len,
                                     dma_addr_t *paddr)
{
        size_t nbytes = (*len < XGENE_DMA_MAX_BYTE_CNT) ?
                        *len : XGENE_DMA_MAX_BYTE_CNT;

        *ext8 |= cpu_to_le64(*paddr);
        *ext8 |= cpu_to_le64(xgene_dma_encode_len(nbytes));
        *len -= nbytes;
        *paddr += nbytes;
}

static __le64 *xgene_dma_lookup_ext8(struct xgene_dma_desc_hw *desc, int idx)
{
        switch (idx) {
        case 0:
                return &desc->m1;
        case 1:
                return &desc->m0;
        case 2:
                return &desc->m3;
        case 3:
                return &desc->m2;
        default:
                pr_err("Invalid dma descriptor index\n");
        }

        return NULL;
}

static void xgene_dma_init_desc(struct xgene_dma_desc_hw *desc,
                                u16 dst_ring_num)
{
        desc->m0 |= cpu_to_le64(XGENE_DMA_DESC_IN_BIT);
        desc->m0 |= cpu_to_le64((u64)XGENE_DMA_RING_OWNER_DMA <<
                                XGENE_DMA_DESC_RTYPE_POS);
        desc->m1 |= cpu_to_le64(XGENE_DMA_DESC_C_BIT);
        desc->m3 |= cpu_to_le64((u64)dst_ring_num <<
                                XGENE_DMA_DESC_HOENQ_NUM_POS);
}

static void xgene_dma_prep_xor_desc(struct xgene_dma_chan *chan,
                                    struct xgene_dma_desc_sw *desc_sw,
                                    dma_addr_t *dst, dma_addr_t *src,
                                    u32 src_cnt, size_t *nbytes,
                                    const u8 *scf)
{
        struct xgene_dma_desc_hw *desc1, *desc2;
        size_t len = *nbytes;
        int i;

        desc1 = &desc_sw->desc1;
        desc2 = &desc_sw->desc2;

        /* Initialize DMA descriptor */
        xgene_dma_init_desc(desc1, chan->tx_ring.dst_ring_num);

        /* Set destination address */
        desc1->m2 |= cpu_to_le64(XGENE_DMA_DESC_DR_BIT);
        desc1->m3 |= cpu_to_le64(*dst);

        /* We have multiple source addresses, so need to set NV bit*/
        desc1->m0 |= cpu_to_le64(XGENE_DMA_DESC_NV_BIT);

        /* Set flyby opcode */
        desc1->m2 |= cpu_to_le64(xgene_dma_encode_xor_flyby(src_cnt));

        /* Set 1st to 5th source addresses */
        for (i = 0; i < src_cnt; i++) {
                len = *nbytes;
                xgene_dma_set_src_buffer((i == 0) ? &desc1->m1 :
                                         xgene_dma_lookup_ext8(desc2, i - 1),
                                         &len, &src[i]);
                desc1->m2 |= cpu_to_le64((scf[i] << ((i + 1) * 8)));
        }

        /* Update meta data */
        *nbytes = len;
        *dst += XGENE_DMA_MAX_BYTE_CNT;

        /* We need always 64B descriptor to perform xor or pq operations */
        desc_sw->flags |= XGENE_DMA_FLAG_64B_DESC;
}

static dma_cookie_t xgene_dma_tx_submit(struct dma_async_tx_descriptor *tx)
{
        struct xgene_dma_desc_sw *desc;
        struct xgene_dma_chan *chan;
        dma_cookie_t cookie;

        if (unlikely(!tx))
                return -EINVAL;

        chan = to_dma_chan(tx->chan);
        desc = to_dma_desc_sw(tx);

        spin_lock_bh(&chan->lock);

        cookie = dma_cookie_assign(tx);

        /* Add this transaction list onto the tail of the pending queue */
        list_splice_tail_init(&desc->tx_list, &chan->ld_pending);

        spin_unlock_bh(&chan->lock);

        return cookie;
}

static void xgene_dma_clean_descriptor(struct xgene_dma_chan *chan,
                                       struct xgene_dma_desc_sw *desc)
{
        list_del(&desc->node);
        chan_dbg(chan, "LD %p free\n", desc);
        dma_pool_free(chan->desc_pool, desc, desc->tx.phys);
}

static struct xgene_dma_desc_sw *xgene_dma_alloc_descriptor(
                                 struct xgene_dma_chan *chan)
{
        struct xgene_dma_desc_sw *desc;
        dma_addr_t phys;

        desc = dma_pool_zalloc(chan->desc_pool, GFP_NOWAIT, &phys);
        if (!desc) {
                chan_err(chan, "Failed to allocate LDs\n");
                return NULL;
        }

        INIT_LIST_HEAD(&desc->tx_list);
        desc->tx.phys = phys;
        desc->tx.tx_submit = xgene_dma_tx_submit;
        dma_async_tx_descriptor_init(&desc->tx, &chan->dma_chan);

        chan_dbg(chan, "LD %p allocated\n", desc);

        return desc;
}

/**
 * xgene_dma_clean_completed_descriptor - free all descriptors which
 * has been completed and acked
 * @chan: X-Gene DMA channel
 *
 * This function is used on all completed and acked descriptors.
 */
static void xgene_dma_clean_completed_descriptor(struct xgene_dma_chan *chan)
{
        struct xgene_dma_desc_sw *desc, *_desc;

        /* Run the callback for each descriptor, in order */
        list_for_each_entry_safe(desc, _desc, &chan->ld_completed, node) {
                if (async_tx_test_ack(&desc->tx))
                        xgene_dma_clean_descriptor(chan, desc);
        }
}

/**
 * xgene_dma_run_tx_complete_actions - cleanup a single link descriptor
 * @chan: X-Gene DMA channel
 * @desc: descriptor to cleanup and free
 *
 * This function is used on a descriptor which has been executed by the DMA
 * controller. It will run any callbacks, submit any dependencies.
 */
static void xgene_dma_run_tx_complete_actions(struct xgene_dma_chan *chan,
                                              struct xgene_dma_desc_sw *desc)
{
        struct dma_async_tx_descriptor *tx = &desc->tx;

        /*
         * If this is not the last transaction in the group,
         * then no need to complete cookie and run any callback as
         * this is not the tx_descriptor which had been sent to caller
         * of this DMA request
         */

        if (tx->cookie == 0)
                return;

        dma_cookie_complete(tx);
        dma_descriptor_unmap(tx);

        /* Run the link descriptor callback function */
        dmaengine_desc_get_callback_invoke(tx, NULL);

        /* Run any dependencies */
        dma_run_dependencies(tx);
}

/**
 * xgene_dma_clean_running_descriptor - move the completed descriptor from
 * ld_running to ld_completed
 * @chan: X-Gene DMA channel
 * @desc: the descriptor which is completed
 *
 * Free the descriptor directly if acked by async_tx api,
 * else move it to queue ld_completed.
 */
static void xgene_dma_clean_running_descriptor(struct xgene_dma_chan *chan,
                                               struct xgene_dma_desc_sw *desc)
{
        /* Remove from the list of running transactions */
        list_del(&desc->node);

        /*
         * the client is allowed to attach dependent operations
         * until 'ack' is set
         */
        if (!async_tx_test_ack(&desc->tx)) {
                /*
                 * Move this descriptor to the list of descriptors which is
                 * completed, but still awaiting the 'ack' bit to be set.
                 */
                list_add_tail(&desc->node, &chan->ld_completed);
                return;
        }

        chan_dbg(chan, "LD %p free\n", desc);
        dma_pool_free(chan->desc_pool, desc, desc->tx.phys);
}

static void xgene_chan_xfer_request(struct xgene_dma_chan *chan,
                                    struct xgene_dma_desc_sw *desc_sw)
{
        struct xgene_dma_ring *ring = &chan->tx_ring;
        struct xgene_dma_desc_hw *desc_hw;

        /* Get hw descriptor from DMA tx ring */
        desc_hw = &ring->desc_hw[ring->head];

        /*
         * Increment the head count to point next
         * descriptor for next time
         */
        if (++ring->head == ring->slots)
                ring->head = 0;

        /* Copy prepared sw descriptor data to hw descriptor */
        memcpy(desc_hw, &desc_sw->desc1, sizeof(*desc_hw));

        /*
         * Check if we have prepared 64B descriptor,
         * in this case we need one more hw descriptor
         */
        if (desc_sw->flags & XGENE_DMA_FLAG_64B_DESC) {
                desc_hw = &ring->desc_hw[ring->head];

                if (++ring->head == ring->slots)
                        ring->head = 0;

                memcpy(desc_hw, &desc_sw->desc2, sizeof(*desc_hw));
        }

        /* Increment the pending transaction count */
        chan->pending += ((desc_sw->flags &
                          XGENE_DMA_FLAG_64B_DESC) ? 2 : 1);

        /* Notify the hw that we have descriptor ready for execution */
        iowrite32((desc_sw->flags & XGENE_DMA_FLAG_64B_DESC) ?
                  2 : 1, ring->cmd);
}

/**
 * xgene_chan_xfer_ld_pending - push any pending transactions to hw
 * @chan : X-Gene DMA channel
 *
 * LOCKING: must hold chan->lock
 */
static void xgene_chan_xfer_ld_pending(struct xgene_dma_chan *chan)
{
        struct xgene_dma_desc_sw *desc_sw, *_desc_sw;

        /*
         * If the list of pending descriptors is empty, then we
         * don't need to do any work at all
         */
        if (list_empty(&chan->ld_pending)) {
                chan_dbg(chan, "No pending LDs\n");
                return;
        }

        /*
         * Move elements from the queue of pending transactions onto the list
         * of running transactions and push it to hw for further executions
         */
        list_for_each_entry_safe(desc_sw, _desc_sw, &chan->ld_pending, node) {
                /*
                 * Check if have pushed max number of transactions to hw
                 * as capable, so let's stop here and will push remaining
                 * elements from pening ld queue after completing some
                 * descriptors that we have already pushed
                 */
                if (chan->pending >= chan->max_outstanding)
                        return;

                xgene_chan_xfer_request(chan, desc_sw);

                /*
                 * Delete this element from ld pending queue and append it to
                 * ld running queue
                 */
                list_move_tail(&desc_sw->node, &chan->ld_running);
        }
}

/**
 * xgene_dma_cleanup_descriptors - cleanup link descriptors which are completed
 * and move them to ld_completed to free until flag 'ack' is set
 * @chan: X-Gene DMA channel
 *
 * This function is used on descriptors which have been executed by the DMA
 * controller. It will run any callbacks, submit any dependencies, then
 * free these descriptors if flag 'ack' is set.
 */
static void xgene_dma_cleanup_descriptors(struct xgene_dma_chan *chan)
{
        struct xgene_dma_ring *ring = &chan->rx_ring;
        struct xgene_dma_desc_sw *desc_sw, *_desc_sw;
        struct xgene_dma_desc_hw *desc_hw;
        struct list_head ld_completed;
        u8 status;

        INIT_LIST_HEAD(&ld_completed);

        spin_lock(&chan->lock);

        /* Clean already completed and acked descriptors */
        xgene_dma_clean_completed_descriptor(chan);

        /* Move all completed descriptors to ld completed queue, in order */
        list_for_each_entry_safe(desc_sw, _desc_sw, &chan->ld_running, node) {
                /* Get subsequent hw descriptor from DMA rx ring */
                desc_hw = &ring->desc_hw[ring->head];

                /* Check if this descriptor has been completed */
                if (unlikely(le64_to_cpu(desc_hw->m0) ==
                             XGENE_DMA_DESC_EMPTY_SIGNATURE))
                        break;

                if (++ring->head == ring->slots)
                        ring->head = 0;

                /* Check if we have any error with DMA transactions */
                status = XGENE_DMA_DESC_STATUS(
                                XGENE_DMA_DESC_ELERR_RD(le64_to_cpu(
                                                        desc_hw->m0)),
                                XGENE_DMA_DESC_LERR_RD(le64_to_cpu(
                                                       desc_hw->m0)));
                if (status) {
                        /* Print the DMA error type */
                        chan_err(chan, "%s\n", xgene_dma_desc_err[status]);

                        /*
                         * We have DMA transactions error here. Dump DMA Tx
                         * and Rx descriptors for this request */
                        XGENE_DMA_DESC_DUMP(&desc_sw->desc1,
                                            "X-Gene DMA TX DESC1: ");

                        if (desc_sw->flags & XGENE_DMA_FLAG_64B_DESC)
                                XGENE_DMA_DESC_DUMP(&desc_sw->desc2,
                                                    "X-Gene DMA TX DESC2: ");

                        XGENE_DMA_DESC_DUMP(desc_hw,
                                            "X-Gene DMA RX ERR DESC: ");
                }

                /* Notify the hw about this completed descriptor */
                iowrite32(-1, ring->cmd);

                /* Mark this hw descriptor as processed */
                desc_hw->m0 = cpu_to_le64(XGENE_DMA_DESC_EMPTY_SIGNATURE);

                /*
                 * Decrement the pending transaction count
                 * as we have processed one
                 */
                chan->pending -= ((desc_sw->flags &
                                  XGENE_DMA_FLAG_64B_DESC) ? 2 : 1);

                /*
                 * Delete this node from ld running queue and append it to
                 * ld completed queue for further processing
                 */
                list_move_tail(&desc_sw->node, &ld_completed);
        }

        /*
         * Start any pending transactions automatically
         * In the ideal case, we keep the DMA controller busy while we go
         * ahead and free the descriptors below.
         */
        xgene_chan_xfer_ld_pending(chan);

        spin_unlock(&chan->lock);

        /* Run the callback for each descriptor, in order */
        list_for_each_entry_safe(desc_sw, _desc_sw, &ld_completed, node) {
                xgene_dma_run_tx_complete_actions(chan, desc_sw);
                xgene_dma_clean_running_descriptor(chan, desc_sw);
        }
}

static int xgene_dma_alloc_chan_resources(struct dma_chan *dchan)
{
        struct xgene_dma_chan *chan = to_dma_chan(dchan);

        /* Has this channel already been allocated? */
        if (chan->desc_pool)
                return 1;

        chan->desc_pool = dma_pool_create(chan->name, chan->dev,
                                          sizeof(struct xgene_dma_desc_sw),
                                          0, 0);
        if (!chan->desc_pool) {
                chan_err(chan, "Failed to allocate descriptor pool\n");
                return -ENOMEM;
        }

        chan_dbg(chan, "Allocate descriptor pool\n");

        return 1;
}

/**
 * xgene_dma_free_desc_list - Free all descriptors in a queue
 * @chan: X-Gene DMA channel
 * @list: the list to free
 *
 * LOCKING: must hold chan->lock
 */
static void xgene_dma_free_desc_list(struct xgene_dma_chan *chan,
                                     struct list_head *list)
{
        struct xgene_dma_desc_sw *desc, *_desc;

        list_for_each_entry_safe(desc, _desc, list, node)
                xgene_dma_clean_descriptor(chan, desc);
}

static void xgene_dma_free_chan_resources(struct dma_chan *dchan)
{
        struct xgene_dma_chan *chan = to_dma_chan(dchan);

        chan_dbg(chan, "Free all resources\n");

        if (!chan->desc_pool)
                return;

        /* Process all running descriptor */
        xgene_dma_cleanup_descriptors(chan);

        spin_lock_bh(&chan->lock);

        /* Clean all link descriptor queues */
        xgene_dma_free_desc_list(chan, &chan->ld_pending);
        xgene_dma_free_desc_list(chan, &chan->ld_running);
        xgene_dma_free_desc_list(chan, &chan->ld_completed);

        spin_unlock_bh(&chan->lock);

        /* Delete this channel DMA pool */
        dma_pool_destroy(chan->desc_pool);
        chan->desc_pool = NULL;
}

static struct dma_async_tx_descriptor *xgene_dma_prep_xor(
        struct dma_chan *dchan, dma_addr_t dst, dma_addr_t *src,
        u32 src_cnt, size_t len, unsigned long flags)
{
        struct xgene_dma_desc_sw *first = NULL, *new;
        struct xgene_dma_chan *chan;
        static u8 multi[XGENE_DMA_MAX_XOR_SRC] = {
                                0x01, 0x01, 0x01, 0x01, 0x01};

        if (unlikely(!dchan || !len))
                return NULL;

        chan = to_dma_chan(dchan);

        do {
                /* Allocate the link descriptor from DMA pool */
                new = xgene_dma_alloc_descriptor(chan);
                if (!new)
                        goto fail;

                /* Prepare xor DMA descriptor */
                xgene_dma_prep_xor_desc(chan, new, &dst, src,
                                        src_cnt, &len, multi);

                if (!first)
                        first = new;

                new->tx.cookie = 0;
                async_tx_ack(&new->tx);

                /* Insert the link descriptor to the LD ring */
                list_add_tail(&new->node, &first->tx_list);
        } while (len);

        new->tx.flags = flags; /* client is in control of this ack */
        new->tx.cookie = -EBUSY;
        list_splice(&first->tx_list, &new->tx_list);

        return &new->tx;

fail:
        if (!first)
                return NULL;

        xgene_dma_free_desc_list(chan, &first->tx_list);
        return NULL;
}

static struct dma_async_tx_descriptor *xgene_dma_prep_pq(
        struct dma_chan *dchan, dma_addr_t *dst, dma_addr_t *src,
        u32 src_cnt, const u8 *scf, size_t len, unsigned long flags)
{
        struct xgene_dma_desc_sw *first = NULL, *new;
        struct xgene_dma_chan *chan;
        size_t _len = len;
        dma_addr_t _src[XGENE_DMA_MAX_XOR_SRC];
        static u8 multi[XGENE_DMA_MAX_XOR_SRC] = {0x01, 0x01, 0x01, 0x01, 0x01};

        if (unlikely(!dchan || !len))
                return NULL;

        chan = to_dma_chan(dchan);

        /*
         * Save source addresses on local variable, may be we have to
         * prepare two descriptor to generate P and Q if both enabled
         * in the flags by client
         */
        memcpy(_src, src, sizeof(*src) * src_cnt);

        if (flags & DMA_PREP_PQ_DISABLE_P)
                len = 0;

        if (flags & DMA_PREP_PQ_DISABLE_Q)
                _len = 0;

        do {
                /* Allocate the link descriptor from DMA pool */
                new = xgene_dma_alloc_descriptor(chan);
                if (!new)
                        goto fail;

                if (!first)
                        first = new;

                new->tx.cookie = 0;
                async_tx_ack(&new->tx);

                /* Insert the link descriptor to the LD ring */
                list_add_tail(&new->node, &first->tx_list);

                /*
                 * Prepare DMA descriptor to generate P,
                 * if DMA_PREP_PQ_DISABLE_P flag is not set
                 */
                if (len) {
                        xgene_dma_prep_xor_desc(chan, new, &dst[0], src,
                                                src_cnt, &len, multi);
                        continue;
                }

                /*
                 * Prepare DMA descriptor to generate Q,
                 * if DMA_PREP_PQ_DISABLE_Q flag is not set
                 */
                if (_len) {
                        xgene_dma_prep_xor_desc(chan, new, &dst[1], _src,
                                                src_cnt, &_len, scf);
                }
        } while (len || _len);

        new->tx.flags = flags; /* client is in control of this ack */
        new->tx.cookie = -EBUSY;
        list_splice(&first->tx_list, &new->tx_list);

        return &new->tx;

fail:
        if (!first)
                return NULL;

        xgene_dma_free_desc_list(chan, &first->tx_list);
        return NULL;
}

static void xgene_dma_issue_pending(struct dma_chan *dchan)
{
        struct xgene_dma_chan *chan = to_dma_chan(dchan);

        spin_lock_bh(&chan->lock);
        xgene_chan_xfer_ld_pending(chan);
        spin_unlock_bh(&chan->lock);
}

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

static void xgene_dma_tasklet_cb(struct tasklet_struct *t)
{
        struct xgene_dma_chan *chan = from_tasklet(chan, t, tasklet);

        /* Run all cleanup for descriptors which have been completed */
        xgene_dma_cleanup_descriptors(chan);

        /* Re-enable DMA channel IRQ */
        enable_irq(chan->rx_irq);
}

static irqreturn_t xgene_dma_chan_ring_isr(int irq, void *id)
{
        struct xgene_dma_chan *chan = (struct xgene_dma_chan *)id;

        BUG_ON(!chan);

        /*
         * Disable DMA channel IRQ until we process completed
         * descriptors
         */
        disable_irq_nosync(chan->rx_irq);

        /*
         * Schedule the tasklet to handle all cleanup of the current
         * transaction. It will start a new transaction if there is
         * one pending.
         */
        tasklet_schedule(&chan->tasklet);

        return IRQ_HANDLED;
}

static irqreturn_t xgene_dma_err_isr(int irq, void *id)
{
        struct xgene_dma *pdma = (struct xgene_dma *)id;
        unsigned long int_mask;
        u32 val, i;

        val = ioread32(pdma->csr_dma + XGENE_DMA_INT);

        /* Clear DMA interrupts */
        iowrite32(val, pdma->csr_dma + XGENE_DMA_INT);

        /* Print DMA error info */
        int_mask = val >> XGENE_DMA_INT_MASK_SHIFT;
        for_each_set_bit(i, &int_mask, ARRAY_SIZE(xgene_dma_err))
                dev_err(pdma->dev,
                        "Interrupt status 0x%08X %s\n", val, xgene_dma_err[i]);

        return IRQ_HANDLED;
}

static void xgene_dma_wr_ring_state(struct xgene_dma_ring *ring)
{
        int i;

        iowrite32(ring->num, ring->pdma->csr_ring + XGENE_DMA_RING_STATE);

        for (i = 0; i < XGENE_DMA_RING_NUM_CONFIG; i++)
                iowrite32(ring->state[i], ring->pdma->csr_ring +
                          XGENE_DMA_RING_STATE_WR_BASE + (i * 4));
}

static void xgene_dma_clr_ring_state(struct xgene_dma_ring *ring)
{
        memset(ring->state, 0, sizeof(u32) * XGENE_DMA_RING_NUM_CONFIG);
        xgene_dma_wr_ring_state(ring);
}

static void xgene_dma_setup_ring(struct xgene_dma_ring *ring)
{
        void *ring_cfg = ring->state;
        u64 addr = ring->desc_paddr;
        u32 i, val;

        ring->slots = ring->size / XGENE_DMA_RING_WQ_DESC_SIZE;

        /* Clear DMA ring state */
        xgene_dma_clr_ring_state(ring);

        /* Set DMA ring type */
        XGENE_DMA_RING_TYPE_SET(ring_cfg, XGENE_DMA_RING_TYPE_REGULAR);

        if (ring->owner == XGENE_DMA_RING_OWNER_DMA) {
                /* Set recombination buffer and timeout */
                XGENE_DMA_RING_RECOMBBUF_SET(ring_cfg);
                XGENE_DMA_RING_RECOMTIMEOUTL_SET(ring_cfg);
                XGENE_DMA_RING_RECOMTIMEOUTH_SET(ring_cfg);
        }

        /* Initialize DMA ring state */
        XGENE_DMA_RING_SELTHRSH_SET(ring_cfg);
        XGENE_DMA_RING_ACCEPTLERR_SET(ring_cfg);
        XGENE_DMA_RING_COHERENT_SET(ring_cfg);
        XGENE_DMA_RING_ADDRL_SET(ring_cfg, addr);
        XGENE_DMA_RING_ADDRH_SET(ring_cfg, addr);
        XGENE_DMA_RING_SIZE_SET(ring_cfg, ring->cfgsize);

        /* Write DMA ring configurations */
        xgene_dma_wr_ring_state(ring);

        /* Set DMA ring id */
        iowrite32(XGENE_DMA_RING_ID_SETUP(ring->id),
                  ring->pdma->csr_ring + XGENE_DMA_RING_ID);

        /* Set DMA ring buffer */
        iowrite32(XGENE_DMA_RING_ID_BUF_SETUP(ring->num),
                  ring->pdma->csr_ring + XGENE_DMA_RING_ID_BUF);

        if (ring->owner != XGENE_DMA_RING_OWNER_CPU)
                return;

        /* Set empty signature to DMA Rx ring descriptors */
        for (i = 0; i < ring->slots; i++) {
                struct xgene_dma_desc_hw *desc;

                desc = &ring->desc_hw[i];
                desc->m0 = cpu_to_le64(XGENE_DMA_DESC_EMPTY_SIGNATURE);
        }

        /* Enable DMA Rx ring interrupt */
        val = ioread32(ring->pdma->csr_ring + XGENE_DMA_RING_NE_INT_MODE);
        XGENE_DMA_RING_NE_INT_MODE_SET(val, ring->buf_num);
        iowrite32(val, ring->pdma->csr_ring + XGENE_DMA_RING_NE_INT_MODE);
}

static void xgene_dma_clear_ring(struct xgene_dma_ring *ring)
{
        u32 ring_id, val;

        if (ring->owner == XGENE_DMA_RING_OWNER_CPU) {
                /* Disable DMA Rx ring interrupt */
                val = ioread32(ring->pdma->csr_ring +
                               XGENE_DMA_RING_NE_INT_MODE);
                XGENE_DMA_RING_NE_INT_MODE_RESET(val, ring->buf_num);
                iowrite32(val, ring->pdma->csr_ring +
                          XGENE_DMA_RING_NE_INT_MODE);
        }

        /* Clear DMA ring state */
        ring_id = XGENE_DMA_RING_ID_SETUP(ring->id);
        iowrite32(ring_id, ring->pdma->csr_ring + XGENE_DMA_RING_ID);

        iowrite32(0, ring->pdma->csr_ring + XGENE_DMA_RING_ID_BUF);
        xgene_dma_clr_ring_state(ring);
}

static void xgene_dma_set_ring_cmd(struct xgene_dma_ring *ring)
{
        ring->cmd_base = ring->pdma->csr_ring_cmd +
                                XGENE_DMA_RING_CMD_BASE_OFFSET((ring->num -
                                                          XGENE_DMA_RING_NUM));

        ring->cmd = ring->cmd_base + XGENE_DMA_RING_CMD_OFFSET;
}

static int xgene_dma_get_ring_size(struct xgene_dma_chan *chan,
                                   enum xgene_dma_ring_cfgsize cfgsize)
{
        int size;

        switch (cfgsize) {
        case XGENE_DMA_RING_CFG_SIZE_512B:
                size = 0x200;
                break;
        case XGENE_DMA_RING_CFG_SIZE_2KB:
                size = 0x800;
                break;
        case XGENE_DMA_RING_CFG_SIZE_16KB:
                size = 0x4000;
                break;
        case XGENE_DMA_RING_CFG_SIZE_64KB:
                size = 0x10000;
                break;
        case XGENE_DMA_RING_CFG_SIZE_512KB:
                size = 0x80000;
                break;
        default:
                chan_err(chan, "Unsupported cfg ring size %d\n", cfgsize);
                return -EINVAL;
        }

        return size;
}

static void xgene_dma_delete_ring_one(struct xgene_dma_ring *ring)
{
        /* Clear DMA ring configurations */
        xgene_dma_clear_ring(ring);

        /* De-allocate DMA ring descriptor */
        if (ring->desc_vaddr) {
                dma_free_coherent(ring->pdma->dev, ring->size,
                                  ring->desc_vaddr, ring->desc_paddr);
                ring->desc_vaddr = NULL;
        }
}

static void xgene_dma_delete_chan_rings(struct xgene_dma_chan *chan)
{
        xgene_dma_delete_ring_one(&chan->rx_ring);
        xgene_dma_delete_ring_one(&chan->tx_ring);
}

static int xgene_dma_create_ring_one(struct xgene_dma_chan *chan,
                                     struct xgene_dma_ring *ring,
                                     enum xgene_dma_ring_cfgsize cfgsize)
{
        int ret;

        /* Setup DMA ring descriptor variables */
        ring->pdma = chan->pdma;
        ring->cfgsize = cfgsize;
        ring->num = chan->pdma->ring_num++;
        ring->id = XGENE_DMA_RING_ID_GET(ring->owner, ring->buf_num);

        ret = xgene_dma_get_ring_size(chan, cfgsize);
        if (ret <= 0)
                return ret;
        ring->size = ret;

        /* Allocate memory for DMA ring descriptor */
        ring->desc_vaddr = dma_alloc_coherent(chan->dev, ring->size,
                                              &ring->desc_paddr, GFP_KERNEL);
        if (!ring->desc_vaddr) {
                chan_err(chan, "Failed to allocate ring desc\n");
                return -ENOMEM;
        }

        /* Configure and enable DMA ring */
        xgene_dma_set_ring_cmd(ring);
        xgene_dma_setup_ring(ring);

        return 0;
}

static int xgene_dma_create_chan_rings(struct xgene_dma_chan *chan)
{
        struct xgene_dma_ring *rx_ring = &chan->rx_ring;
        struct xgene_dma_ring *tx_ring = &chan->tx_ring;
        int ret;

        /* Create DMA Rx ring descriptor */
        rx_ring->owner = XGENE_DMA_RING_OWNER_CPU;
        rx_ring->buf_num = XGENE_DMA_CPU_BUFNUM + chan->id;

        ret = xgene_dma_create_ring_one(chan, rx_ring,
                                        XGENE_DMA_RING_CFG_SIZE_64KB);
        if (ret)
                return ret;

        chan_dbg(chan, "Rx ring id 0x%X num %d desc 0x%p\n",
                 rx_ring->id, rx_ring->num, rx_ring->desc_vaddr);

        /* Create DMA Tx ring descriptor */
        tx_ring->owner = XGENE_DMA_RING_OWNER_DMA;
        tx_ring->buf_num = XGENE_DMA_BUFNUM + chan->id;

        ret = xgene_dma_create_ring_one(chan, tx_ring,
                                        XGENE_DMA_RING_CFG_SIZE_64KB);
        if (ret) {
                xgene_dma_delete_ring_one(rx_ring);
                return ret;
        }

        tx_ring->dst_ring_num = XGENE_DMA_RING_DST_ID(rx_ring->num);

        chan_dbg(chan,
                 "Tx ring id 0x%X num %d desc 0x%p\n",
                 tx_ring->id, tx_ring->num, tx_ring->desc_vaddr);

        /* Set the max outstanding request possible to this channel */
        chan->max_outstanding = tx_ring->slots;

        return ret;
}

static int xgene_dma_init_rings(struct xgene_dma *pdma)
{
        int ret, i, j;

        for (i = 0; i < XGENE_DMA_MAX_CHANNEL; i++) {
                ret = xgene_dma_create_chan_rings(&pdma->chan[i]);
                if (ret) {
                        for (j = 0; j < i; j++)
                                xgene_dma_delete_chan_rings(&pdma->chan[j]);
                        return ret;
                }
        }

        return ret;
}

static void xgene_dma_enable(struct xgene_dma *pdma)
{
        u32 val;

        /* Configure and enable DMA engine */
        val = ioread32(pdma->csr_dma + XGENE_DMA_GCR);
        XGENE_DMA_CH_SETUP(val);
        XGENE_DMA_ENABLE(val);
        iowrite32(val, pdma->csr_dma + XGENE_DMA_GCR);
}

static void xgene_dma_disable(struct xgene_dma *pdma)
{
        u32 val;

        val = ioread32(pdma->csr_dma + XGENE_DMA_GCR);
        XGENE_DMA_DISABLE(val);
        iowrite32(val, pdma->csr_dma + XGENE_DMA_GCR);
}

static void xgene_dma_mask_interrupts(struct xgene_dma *pdma)
{
        /*
         * Mask DMA ring overflow, underflow and
         * AXI write/read error interrupts
         */
        iowrite32(XGENE_DMA_INT_ALL_MASK,
                  pdma->csr_dma + XGENE_DMA_RING_INT0_MASK);
        iowrite32(XGENE_DMA_INT_ALL_MASK,
                  pdma->csr_dma + XGENE_DMA_RING_INT1_MASK);
        iowrite32(XGENE_DMA_INT_ALL_MASK,
                  pdma->csr_dma + XGENE_DMA_RING_INT2_MASK);
        iowrite32(XGENE_DMA_INT_ALL_MASK,
                  pdma->csr_dma + XGENE_DMA_RING_INT3_MASK);
        iowrite32(XGENE_DMA_INT_ALL_MASK,
                  pdma->csr_dma + XGENE_DMA_RING_INT4_MASK);

        /* Mask DMA error interrupts */
        iowrite32(XGENE_DMA_INT_ALL_MASK, pdma->csr_dma + XGENE_DMA_INT_MASK);
}

static void xgene_dma_unmask_interrupts(struct xgene_dma *pdma)
{
        /*
         * Unmask DMA ring overflow, underflow and
         * AXI write/read error interrupts
         */
        iowrite32(XGENE_DMA_INT_ALL_UNMASK,
                  pdma->csr_dma + XGENE_DMA_RING_INT0_MASK);
        iowrite32(XGENE_DMA_INT_ALL_UNMASK,
                  pdma->csr_dma + XGENE_DMA_RING_INT1_MASK);
        iowrite32(XGENE_DMA_INT_ALL_UNMASK,
                  pdma->csr_dma + XGENE_DMA_RING_INT2_MASK);
        iowrite32(XGENE_DMA_INT_ALL_UNMASK,
                  pdma->csr_dma + XGENE_DMA_RING_INT3_MASK);
        iowrite32(XGENE_DMA_INT_ALL_UNMASK,
                  pdma->csr_dma + XGENE_DMA_RING_INT4_MASK);

        /* Unmask DMA error interrupts */
        iowrite32(XGENE_DMA_INT_ALL_UNMASK,
                  pdma->csr_dma + XGENE_DMA_INT_MASK);
}

static void xgene_dma_init_hw(struct xgene_dma *pdma)
{
        u32 val;

        /* Associate DMA ring to corresponding ring HW */
        iowrite32(XGENE_DMA_ASSOC_RING_MNGR1,
                  pdma->csr_dma + XGENE_DMA_CFG_RING_WQ_ASSOC);

        /* Configure RAID6 polynomial control setting */
        if (is_pq_enabled(pdma))
                iowrite32(XGENE_DMA_RAID6_MULTI_CTRL(0x1D),
                          pdma->csr_dma + XGENE_DMA_RAID6_CONT);
        else
                dev_info(pdma->dev, "PQ is disabled in HW\n");

        xgene_dma_enable(pdma);
        xgene_dma_unmask_interrupts(pdma);

        /* Get DMA id and version info */
        val = ioread32(pdma->csr_dma + XGENE_DMA_IPBRR);

        /* DMA device info */
        dev_info(pdma->dev,
                 "X-Gene DMA v%d.%02d.%02d driver registered %d channels",
                 XGENE_DMA_REV_NO_RD(val), XGENE_DMA_BUS_ID_RD(val),
                 XGENE_DMA_DEV_ID_RD(val), XGENE_DMA_MAX_CHANNEL);
}

static int xgene_dma_init_ring_mngr(struct xgene_dma *pdma)
{
        if (ioread32(pdma->csr_ring + XGENE_DMA_RING_CLKEN) &&
            (!ioread32(pdma->csr_ring + XGENE_DMA_RING_SRST)))
                return 0;

        iowrite32(0x3, pdma->csr_ring + XGENE_DMA_RING_CLKEN);
        iowrite32(0x0, pdma->csr_ring + XGENE_DMA_RING_SRST);

        /* Bring up memory */
        iowrite32(0x0, pdma->csr_ring + XGENE_DMA_RING_MEM_RAM_SHUTDOWN);

        /* Force a barrier */
        ioread32(pdma->csr_ring + XGENE_DMA_RING_MEM_RAM_SHUTDOWN);

        /* reset may take up to 1ms */
        usleep_range(1000, 1100);

        if (ioread32(pdma->csr_ring + XGENE_DMA_RING_BLK_MEM_RDY)
                != XGENE_DMA_RING_BLK_MEM_RDY_VAL) {
                dev_err(pdma->dev,
                        "Failed to release ring mngr memory from shutdown\n");
                return -ENODEV;
        }

        /* program threshold set 1 and all hysteresis */
        iowrite32(XGENE_DMA_RING_THRESLD0_SET1_VAL,
                  pdma->csr_ring + XGENE_DMA_RING_THRESLD0_SET1);
        iowrite32(XGENE_DMA_RING_THRESLD1_SET1_VAL,
                  pdma->csr_ring + XGENE_DMA_RING_THRESLD1_SET1);
        iowrite32(XGENE_DMA_RING_HYSTERESIS_VAL,
                  pdma->csr_ring + XGENE_DMA_RING_HYSTERESIS);

        /* Enable QPcore and assign error queue */
        iowrite32(XGENE_DMA_RING_ENABLE,
                  pdma->csr_ring + XGENE_DMA_RING_CONFIG);

        return 0;
}

static int xgene_dma_init_mem(struct xgene_dma *pdma)
{
        int ret;

        ret = xgene_dma_init_ring_mngr(pdma);
        if (ret)
                return ret;

        /* Bring up memory */
        iowrite32(0x0, pdma->csr_dma + XGENE_DMA_MEM_RAM_SHUTDOWN);

        /* Force a barrier */
        ioread32(pdma->csr_dma + XGENE_DMA_MEM_RAM_SHUTDOWN);

        /* reset may take up to 1ms */
        usleep_range(1000, 1100);

        if (ioread32(pdma->csr_dma + XGENE_DMA_BLK_MEM_RDY)
                != XGENE_DMA_BLK_MEM_RDY_VAL) {
                dev_err(pdma->dev,
                        "Failed to release DMA memory from shutdown\n");
                return -ENODEV;
        }

        return 0;
}

static int xgene_dma_request_irqs(struct xgene_dma *pdma)
{
        struct xgene_dma_chan *chan;
        int ret, i, j;

        /* Register DMA error irq */
        ret = devm_request_irq(pdma->dev, pdma->err_irq, xgene_dma_err_isr,
                               0, "dma_error", pdma);
        if (ret) {
                dev_err(pdma->dev,
                        "Failed to register error IRQ %d\n", pdma->err_irq);
                return ret;
        }

        /* Register DMA channel rx irq */
        for (i = 0; i < XGENE_DMA_MAX_CHANNEL; i++) {
                chan = &pdma->chan[i];
                irq_set_status_flags(chan->rx_irq, IRQ_DISABLE_UNLAZY);
                ret = devm_request_irq(chan->dev, chan->rx_irq,
                                       xgene_dma_chan_ring_isr,
                                       0, chan->name, chan);
                if (ret) {
                        chan_err(chan, "Failed to register Rx IRQ %d\n",
                                 chan->rx_irq);
                        devm_free_irq(pdma->dev, pdma->err_irq, pdma);

                        for (j = 0; j < i; j++) {
                                chan = &pdma->chan[i];
                                irq_clear_status_flags(chan->rx_irq, IRQ_DISABLE_UNLAZY);
                                devm_free_irq(chan->dev, chan->rx_irq, chan);
                        }

                        return ret;
                }
        }

        return 0;
}

static void xgene_dma_free_irqs(struct xgene_dma *pdma)
{
        struct xgene_dma_chan *chan;
        int i;

        /* Free DMA device error irq */
        devm_free_irq(pdma->dev, pdma->err_irq, pdma);

        for (i = 0; i < XGENE_DMA_MAX_CHANNEL; i++) {
                chan = &pdma->chan[i];
                irq_clear_status_flags(chan->rx_irq, IRQ_DISABLE_UNLAZY);
                devm_free_irq(chan->dev, chan->rx_irq, chan);
        }
}

static void xgene_dma_set_caps(struct xgene_dma_chan *chan,
                               struct dma_device *dma_dev)
{
        /* Initialize DMA device capability mask */
        dma_cap_zero(dma_dev->cap_mask);

        /* Set DMA device capability */

        /* Basically here, the X-Gene SoC DMA engine channel 0 supports XOR
         * and channel 1 supports XOR, PQ both. First thing here is we have
         * mechanism in hw to enable/disable PQ/XOR supports on channel 1,
         * we can make sure this by reading SoC Efuse register.
         * Second thing, we have hw errata that if we run channel 0 and
         * channel 1 simultaneously with executing XOR and PQ request,
         * suddenly DMA engine hangs, So here we enable XOR on channel 0 only
         * if XOR and PQ supports on channel 1 is disabled.
         */
        if ((chan->id == XGENE_DMA_PQ_CHANNEL) &&
            is_pq_enabled(chan->pdma)) {
                dma_cap_set(DMA_PQ, dma_dev->cap_mask);
                dma_cap_set(DMA_XOR, dma_dev->cap_mask);
        } else if ((chan->id == XGENE_DMA_XOR_CHANNEL) &&
                   !is_pq_enabled(chan->pdma)) {
                dma_cap_set(DMA_XOR, dma_dev->cap_mask);
        }

        /* Set base and prep routines */
        dma_dev->dev = chan->dev;
        dma_dev->device_alloc_chan_resources = xgene_dma_alloc_chan_resources;
        dma_dev->device_free_chan_resources = xgene_dma_free_chan_resources;
        dma_dev->device_issue_pending = xgene_dma_issue_pending;
        dma_dev->device_tx_status = xgene_dma_tx_status;

        if (dma_has_cap(DMA_XOR, dma_dev->cap_mask)) {
                dma_dev->device_prep_dma_xor = xgene_dma_prep_xor;
                dma_dev->max_xor = XGENE_DMA_MAX_XOR_SRC;
                dma_dev->xor_align = DMAENGINE_ALIGN_64_BYTES;
        }

        if (dma_has_cap(DMA_PQ, dma_dev->cap_mask)) {
                dma_dev->device_prep_dma_pq = xgene_dma_prep_pq;
                dma_dev->max_pq = XGENE_DMA_MAX_XOR_SRC;
                dma_dev->pq_align = DMAENGINE_ALIGN_64_BYTES;
        }
}

static int xgene_dma_async_register(struct xgene_dma *pdma, int id)
{
        struct xgene_dma_chan *chan = &pdma->chan[id];
        struct dma_device *dma_dev = &pdma->dma_dev[id];
        int ret;

        chan->dma_chan.device = dma_dev;

        spin_lock_init(&chan->lock);
        INIT_LIST_HEAD(&chan->ld_pending);
        INIT_LIST_HEAD(&chan->ld_running);
        INIT_LIST_HEAD(&chan->ld_completed);
        tasklet_setup(&chan->tasklet, xgene_dma_tasklet_cb);

        chan->pending = 0;
        chan->desc_pool = NULL;
        dma_cookie_init(&chan->dma_chan);

        /* Setup dma device capabilities and prep routines */
        xgene_dma_set_caps(chan, dma_dev);

        /* Initialize DMA device list head */
        INIT_LIST_HEAD(&dma_dev->channels);
        list_add_tail(&chan->dma_chan.device_node, &dma_dev->channels);

        /* Register with Linux async DMA framework*/
        ret = dma_async_device_register(dma_dev);
        if (ret) {
                chan_err(chan, "Failed to register async device %d", ret);
                tasklet_kill(&chan->tasklet);

                return ret;
        }

        /* DMA capability info */
        dev_info(pdma->dev,
                 "%s: CAPABILITY ( %s%s)\n", dma_chan_name(&chan->dma_chan),
                 dma_has_cap(DMA_XOR, dma_dev->cap_mask) ? "XOR " : "",
                 dma_has_cap(DMA_PQ, dma_dev->cap_mask) ? "PQ " : "");

        return 0;
}

static int xgene_dma_init_async(struct xgene_dma *pdma)
{
        int ret, i, j;

        for (i = 0; i < XGENE_DMA_MAX_CHANNEL ; i++) {
                ret = xgene_dma_async_register(pdma, i);
                if (ret) {
                        for (j = 0; j < i; j++) {
                                dma_async_device_unregister(&pdma->dma_dev[j]);
                                tasklet_kill(&pdma->chan[j].tasklet);
                        }

                        return ret;
                }
        }

        return ret;
}

static void xgene_dma_async_unregister(struct xgene_dma *pdma)
{
        int i;

        for (i = 0; i < XGENE_DMA_MAX_CHANNEL; i++)
                dma_async_device_unregister(&pdma->dma_dev[i]);
}

static void xgene_dma_init_channels(struct xgene_dma *pdma)
{
        struct xgene_dma_chan *chan;
        int i;

        pdma->ring_num = XGENE_DMA_RING_NUM;

        for (i = 0; i < XGENE_DMA_MAX_CHANNEL; i++) {
                chan = &pdma->chan[i];
                chan->dev = pdma->dev;
                chan->pdma = pdma;
                chan->id = i;
                snprintf(chan->name, sizeof(chan->name), "dmachan%d", chan->id);
        }
}

static int xgene_dma_get_resources(struct platform_device *pdev,
                                   struct xgene_dma *pdma)
{
        struct resource *res;
        int irq, i;

        /* Get DMA csr region */
        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        if (!res) {
                dev_err(&pdev->dev, "Failed to get csr region\n");
                return -ENXIO;
        }

        pdma->csr_dma = devm_ioremap(&pdev->dev, res->start,
                                     resource_size(res));
        if (!pdma->csr_dma) {
                dev_err(&pdev->dev, "Failed to ioremap csr region");
                return -ENOMEM;
        }

        /* Get DMA ring csr region */
        res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
        if (!res) {
                dev_err(&pdev->dev, "Failed to get ring csr region\n");
                return -ENXIO;
        }

        pdma->csr_ring =  devm_ioremap(&pdev->dev, res->start,
                                       resource_size(res));
        if (!pdma->csr_ring) {
                dev_err(&pdev->dev, "Failed to ioremap ring csr region");
                return -ENOMEM;
        }

        /* Get DMA ring cmd csr region */
        res = platform_get_resource(pdev, IORESOURCE_MEM, 2);
        if (!res) {
                dev_err(&pdev->dev, "Failed to get ring cmd csr region\n");
                return -ENXIO;
        }

        pdma->csr_ring_cmd = devm_ioremap(&pdev->dev, res->start,
                                          resource_size(res));
        if (!pdma->csr_ring_cmd) {
                dev_err(&pdev->dev, "Failed to ioremap ring cmd csr region");
                return -ENOMEM;
        }

        pdma->csr_ring_cmd += XGENE_DMA_RING_CMD_SM_OFFSET;

        /* Get efuse csr region */
        res = platform_get_resource(pdev, IORESOURCE_MEM, 3);
        if (!res) {
                dev_err(&pdev->dev, "Failed to get efuse csr region\n");
                return -ENXIO;
        }

        pdma->csr_efuse = devm_ioremap(&pdev->dev, res->start,
                                       resource_size(res));
        if (!pdma->csr_efuse) {
                dev_err(&pdev->dev, "Failed to ioremap efuse csr region");
                return -ENOMEM;
        }

        /* Get DMA error interrupt */
        irq = platform_get_irq(pdev, 0);
        if (irq <= 0)
                return -ENXIO;

        pdma->err_irq = irq;

        /* Get DMA Rx ring descriptor interrupts for all DMA channels */
        for (i = 1; i <= XGENE_DMA_MAX_CHANNEL; i++) {
                irq = platform_get_irq(pdev, i);
                if (irq <= 0)
                        return -ENXIO;

                pdma->chan[i - 1].rx_irq = irq;
        }

        return 0;
}

static int xgene_dma_probe(struct platform_device *pdev)
{
        struct xgene_dma *pdma;
        int ret, i;

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

        pdma->dev = &pdev->dev;
        platform_set_drvdata(pdev, pdma);

        ret = xgene_dma_get_resources(pdev, pdma);
        if (ret)
                return ret;

        pdma->clk = devm_clk_get(&pdev->dev, NULL);
        if (IS_ERR(pdma->clk) && !ACPI_COMPANION(&pdev->dev)) {
                dev_err(&pdev->dev, "Failed to get clk\n");
                return PTR_ERR(pdma->clk);
        }

        /* Enable clk before accessing registers */
        if (!IS_ERR(pdma->clk)) {
                ret = clk_prepare_enable(pdma->clk);
                if (ret) {
                        dev_err(&pdev->dev, "Failed to enable clk %d\n", ret);
                        return ret;
                }
        }

        /* Remove DMA RAM out of shutdown */
        ret = xgene_dma_init_mem(pdma);
        if (ret)
                goto err_clk_enable;

        ret = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(42));
        if (ret) {
                dev_err(&pdev->dev, "No usable DMA configuration\n");
                goto err_dma_mask;
        }

        /* Initialize DMA channels software state */
        xgene_dma_init_channels(pdma);

        /* Configue DMA rings */
        ret = xgene_dma_init_rings(pdma);
        if (ret)
                goto err_clk_enable;

        ret = xgene_dma_request_irqs(pdma);
        if (ret)
                goto err_request_irq;

        /* Configure and enable DMA engine */
        xgene_dma_init_hw(pdma);

        /* Register DMA device with linux async framework */
        ret = xgene_dma_init_async(pdma);
        if (ret)
                goto err_async_init;

        return 0;

err_async_init:
        xgene_dma_free_irqs(pdma);

err_request_irq:
        for (i = 0; i < XGENE_DMA_MAX_CHANNEL; i++)
                xgene_dma_delete_chan_rings(&pdma->chan[i]);

err_dma_mask:
err_clk_enable:
        if (!IS_ERR(pdma->clk))
                clk_disable_unprepare(pdma->clk);

        return ret;
}

static int xgene_dma_remove(struct platform_device *pdev)
{
        struct xgene_dma *pdma = platform_get_drvdata(pdev);
        struct xgene_dma_chan *chan;
        int i;

        xgene_dma_async_unregister(pdma);

        /* Mask interrupts and disable DMA engine */
        xgene_dma_mask_interrupts(pdma);
        xgene_dma_disable(pdma);
        xgene_dma_free_irqs(pdma);

        for (i = 0; i < XGENE_DMA_MAX_CHANNEL; i++) {
                chan = &pdma->chan[i];
                tasklet_kill(&chan->tasklet);
                xgene_dma_delete_chan_rings(chan);
        }

        if (!IS_ERR(pdma->clk))
                clk_disable_unprepare(pdma->clk);

        return 0;
}

#ifdef CONFIG_ACPI
static const struct acpi_device_id xgene_dma_acpi_match_ptr[] = {
        {"APMC0D43", 0},
        {},
};
MODULE_DEVICE_TABLE(acpi, xgene_dma_acpi_match_ptr);
#endif

static const struct of_device_id xgene_dma_of_match_ptr[] = {
        {.compatible = "apm,xgene-storm-dma",},
        {},
};
MODULE_DEVICE_TABLE(of, xgene_dma_of_match_ptr);

static struct platform_driver xgene_dma_driver = {
        .probe = xgene_dma_probe,
        .remove = xgene_dma_remove,
        .driver = {
                .name = "X-Gene-DMA",
                .of_match_table = xgene_dma_of_match_ptr,
                .acpi_match_table = ACPI_PTR(xgene_dma_acpi_match_ptr),
        },
};

module_platform_driver(xgene_dma_driver);

MODULE_DESCRIPTION("APM X-Gene SoC DMA driver");
MODULE_AUTHOR("Rameshwar Prasad Sahu <rsahu@apm.com>");
MODULE_AUTHOR("Loc Ho <lho@apm.com>");
MODULE_LICENSE("GPL");
MODULE_VERSION("1.0");