// SPDX-License-Identifier: GPL-2.0-only
/*
 * Huawei HiNIC PCI Express Linux driver
 * Copyright(c) 2017 Huawei Technologies Co., Ltd
 */

#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/pci.h>
#include <linux/device.h>
#include <linux/slab.h>
#include <linux/dma-mapping.h>
#include <linux/bitops.h>
#include <linux/err.h>
#include <linux/jiffies.h>
#include <linux/delay.h>
#include <linux/log2.h>
#include <linux/semaphore.h>
#include <asm/byteorder.h>
#include <asm/barrier.h>

#include "hinic_hw_csr.h"
#include "hinic_hw_if.h"
#include "hinic_hw_api_cmd.h"

#define API_CHAIN_NUM_CELLS                     32

#define API_CMD_CELL_SIZE_SHIFT                 6
#define API_CMD_CELL_SIZE_MIN                   (BIT(API_CMD_CELL_SIZE_SHIFT))

#define API_CMD_CELL_SIZE(cell_size)            \
                (((cell_size) >= API_CMD_CELL_SIZE_MIN) ? \
                 (1 << (fls(cell_size - 1))) : API_CMD_CELL_SIZE_MIN)

#define API_CMD_CELL_SIZE_VAL(size)             \
                ilog2((size) >> API_CMD_CELL_SIZE_SHIFT)

#define API_CMD_BUF_SIZE                        2048

/* Sizes of the members in hinic_api_cmd_cell */
#define API_CMD_CELL_DESC_SIZE          8
#define API_CMD_CELL_DATA_ADDR_SIZE     8

#define API_CMD_CELL_ALIGNMENT          8

#define API_CMD_TIMEOUT                 1000

#define MASKED_IDX(chain, idx)          ((idx) & ((chain)->num_cells - 1))

#define SIZE_8BYTES(size)               (ALIGN((size), 8) >> 3)
#define SIZE_4BYTES(size)               (ALIGN((size), 4) >> 2)

#define RD_DMA_ATTR_DEFAULT             0
#define WR_DMA_ATTR_DEFAULT             0

enum api_cmd_data_format {
        SGE_DATA = 1,           /* cell data is passed by hw address */
};

enum api_cmd_type {
        API_CMD_WRITE = 0,
};

enum api_cmd_bypass {
        NO_BYPASS       = 0,
        BYPASS          = 1,
};

enum api_cmd_xor_chk_level {
        XOR_CHK_DIS = 0,

        XOR_CHK_ALL = 3,
};

static u8 xor_chksum_set(void *data)
{
        int idx;
        u8 *val, checksum = 0;

        val = data;

        for (idx = 0; idx < 7; idx++)
                checksum ^= val[idx];

        return checksum;
}

static void set_prod_idx(struct hinic_api_cmd_chain *chain)
{
        enum hinic_api_cmd_chain_type chain_type = chain->chain_type;
        struct hinic_hwif *hwif = chain->hwif;
        u32 addr, prod_idx;

        addr = HINIC_CSR_API_CMD_CHAIN_PI_ADDR(chain_type);
        prod_idx = hinic_hwif_read_reg(hwif, addr);

        prod_idx = HINIC_API_CMD_PI_CLEAR(prod_idx, IDX);

        prod_idx |= HINIC_API_CMD_PI_SET(chain->prod_idx, IDX);

        hinic_hwif_write_reg(hwif, addr, prod_idx);
}

static u32 get_hw_cons_idx(struct hinic_api_cmd_chain *chain)
{
        u32 addr, val;

        addr = HINIC_CSR_API_CMD_STATUS_ADDR(chain->chain_type);
        val  = hinic_hwif_read_reg(chain->hwif, addr);

        return HINIC_API_CMD_STATUS_GET(val, CONS_IDX);
}

static void dump_api_chain_reg(struct hinic_api_cmd_chain *chain)
{
        u32 addr, val;

        addr = HINIC_CSR_API_CMD_STATUS_ADDR(chain->chain_type);
        val  = hinic_hwif_read_reg(chain->hwif, addr);

        dev_err(&chain->hwif->pdev->dev, "Chain type: 0x%x, cpld error: 0x%x, check error: 0x%x, current fsm: 0x%x\n",
                chain->chain_type, HINIC_API_CMD_STATUS_GET(val, CPLD_ERR),
                HINIC_API_CMD_STATUS_GET(val, CHKSUM_ERR),
                HINIC_API_CMD_STATUS_GET(val, FSM));

        dev_err(&chain->hwif->pdev->dev, "Chain hw current ci: 0x%x\n",
                HINIC_API_CMD_STATUS_GET(val, CONS_IDX));

        addr = HINIC_CSR_API_CMD_CHAIN_PI_ADDR(chain->chain_type);
        val  = hinic_hwif_read_reg(chain->hwif, addr);
        dev_err(&chain->hwif->pdev->dev, "Chain hw current pi: 0x%x\n", val);
}

/**
 * chain_busy - check if the chain is still processing last requests
 * @chain: chain to check
 *
 * Return 0 - Success, negative - Failure
 **/
static int chain_busy(struct hinic_api_cmd_chain *chain)
{
        struct hinic_hwif *hwif = chain->hwif;
        struct pci_dev *pdev = hwif->pdev;
        u32 prod_idx;

        switch (chain->chain_type) {
        case HINIC_API_CMD_WRITE_TO_MGMT_CPU:
                chain->cons_idx = get_hw_cons_idx(chain);
                prod_idx = chain->prod_idx;

                /* check for a space for a new command */
                if (chain->cons_idx == MASKED_IDX(chain, prod_idx + 1)) {
                        dev_err(&pdev->dev, "API CMD chain %d is busy, cons_idx: %d, prod_idx: %d\n",
                                chain->chain_type, chain->cons_idx,
                                chain->prod_idx);
                        dump_api_chain_reg(chain);
                        return -EBUSY;
                }
                break;

        default:
                dev_err(&pdev->dev, "Unknown API CMD Chain type\n");
                break;
        }

        return 0;
}

/**
 * get_cell_data_size - get the data size of a specific cell type
 * @type: chain type
 *
 * Return the data(Desc + Address) size in the cell
 **/
static u8 get_cell_data_size(enum hinic_api_cmd_chain_type type)
{
        u8 cell_data_size = 0;

        switch (type) {
        case HINIC_API_CMD_WRITE_TO_MGMT_CPU:
                cell_data_size = ALIGN(API_CMD_CELL_DESC_SIZE +
                                       API_CMD_CELL_DATA_ADDR_SIZE,
                                       API_CMD_CELL_ALIGNMENT);
                break;
        default:
                break;
        }

        return cell_data_size;
}

/**
 * prepare_cell_ctrl - prepare the ctrl of the cell for the command
 * @cell_ctrl: the control of the cell to set the control value into it
 * @data_size: the size of the data in the cell
 **/
static void prepare_cell_ctrl(u64 *cell_ctrl, u16 data_size)
{
        u8 chksum;
        u64 ctrl;

        ctrl =  HINIC_API_CMD_CELL_CTRL_SET(SIZE_8BYTES(data_size), DATA_SZ)  |
                HINIC_API_CMD_CELL_CTRL_SET(RD_DMA_ATTR_DEFAULT, RD_DMA_ATTR) |
                HINIC_API_CMD_CELL_CTRL_SET(WR_DMA_ATTR_DEFAULT, WR_DMA_ATTR);

        chksum = xor_chksum_set(&ctrl);

        ctrl |= HINIC_API_CMD_CELL_CTRL_SET(chksum, XOR_CHKSUM);

        /* The data in the HW should be in Big Endian Format */
        *cell_ctrl = cpu_to_be64(ctrl);
}

/**
 * prepare_api_cmd - prepare API CMD command
 * @chain: chain for the command
 * @dest: destination node on the card that will receive the command
 * @cmd: command data
 * @cmd_size: the command size
 **/
static void prepare_api_cmd(struct hinic_api_cmd_chain *chain,
                            enum hinic_node_id dest,
                            void *cmd, u16 cmd_size)
{
        struct hinic_api_cmd_cell *cell = chain->curr_node;
        struct hinic_api_cmd_cell_ctxt *cell_ctxt;
        struct hinic_hwif *hwif = chain->hwif;
        struct pci_dev *pdev = hwif->pdev;

        cell_ctxt = &chain->cell_ctxt[chain->prod_idx];

        switch (chain->chain_type) {
        case HINIC_API_CMD_WRITE_TO_MGMT_CPU:
                cell->desc = HINIC_API_CMD_DESC_SET(SGE_DATA, API_TYPE)   |
                             HINIC_API_CMD_DESC_SET(API_CMD_WRITE, RD_WR) |
                             HINIC_API_CMD_DESC_SET(NO_BYPASS, MGMT_BYPASS);
                break;

        default:
                dev_err(&pdev->dev, "unknown Chain type\n");
                return;
        }

        cell->desc |= HINIC_API_CMD_DESC_SET(dest, DEST)        |
                      HINIC_API_CMD_DESC_SET(SIZE_4BYTES(cmd_size), SIZE);

        cell->desc |= HINIC_API_CMD_DESC_SET(xor_chksum_set(&cell->desc),
                                             XOR_CHKSUM);

        /* The data in the HW should be in Big Endian Format */
        cell->desc = cpu_to_be64(cell->desc);

        memcpy(cell_ctxt->api_cmd_vaddr, cmd, cmd_size);
}

/**
 * prepare_cell - prepare cell ctrl and cmd in the current cell
 * @chain: chain for the command
 * @dest: destination node on the card that will receive the command
 * @cmd: command data
 * @cmd_size: the command size
 *
 * Return 0 - Success, negative - Failure
 **/
static void prepare_cell(struct hinic_api_cmd_chain *chain,
                         enum  hinic_node_id dest,
                         void *cmd, u16 cmd_size)
{
        struct hinic_api_cmd_cell *curr_node = chain->curr_node;
        u16 data_size = get_cell_data_size(chain->chain_type);

        prepare_cell_ctrl(&curr_node->ctrl, data_size);
        prepare_api_cmd(chain, dest, cmd, cmd_size);
}

static inline void cmd_chain_prod_idx_inc(struct hinic_api_cmd_chain *chain)
{
        chain->prod_idx = MASKED_IDX(chain, chain->prod_idx + 1);
}

/**
 * api_cmd_status_update - update the status in the chain struct
 * @chain: chain to update
 **/
static void api_cmd_status_update(struct hinic_api_cmd_chain *chain)
{
        enum hinic_api_cmd_chain_type chain_type;
        struct hinic_api_cmd_status *wb_status;
        struct hinic_hwif *hwif = chain->hwif;
        struct pci_dev *pdev = hwif->pdev;
        u64 status_header;
        u32 status;

        wb_status = chain->wb_status;
        status_header = be64_to_cpu(wb_status->header);

        status = be32_to_cpu(wb_status->status);
        if (HINIC_API_CMD_STATUS_GET(status, CHKSUM_ERR)) {
                dev_err(&pdev->dev, "API CMD status: Xor check error\n");
                return;
        }

        chain_type = HINIC_API_CMD_STATUS_HEADER_GET(status_header, CHAIN_ID);
        if (chain_type >= HINIC_API_CMD_MAX) {
                dev_err(&pdev->dev, "unknown API CMD Chain %d\n", chain_type);
                return;
        }

        chain->cons_idx = HINIC_API_CMD_STATUS_GET(status, CONS_IDX);
}

/**
 * wait_for_status_poll - wait for write to api cmd command to complete
 * @chain: the chain of the command
 *
 * Return 0 - Success, negative - Failure
 **/
static int wait_for_status_poll(struct hinic_api_cmd_chain *chain)
{
        int err = -ETIMEDOUT;
        unsigned long end;

        end = jiffies + msecs_to_jiffies(API_CMD_TIMEOUT);
        do {
                api_cmd_status_update(chain);

                /* wait for CI to be updated - sign for completion */
                if (chain->cons_idx == chain->prod_idx) {
                        err = 0;
                        break;
                }

                msleep(20);
        } while (time_before(jiffies, end));

        return err;
}

/**
 * wait_for_api_cmd_completion - wait for command to complete
 * @chain: chain for the command
 *
 * Return 0 - Success, negative - Failure
 **/
static int wait_for_api_cmd_completion(struct hinic_api_cmd_chain *chain)
{
        struct hinic_hwif *hwif = chain->hwif;
        struct pci_dev *pdev = hwif->pdev;
        int err;

        switch (chain->chain_type) {
        case HINIC_API_CMD_WRITE_TO_MGMT_CPU:
                err = wait_for_status_poll(chain);
                if (err) {
                        dev_err(&pdev->dev, "API CMD Poll status timeout\n");
                        dump_api_chain_reg(chain);
                        break;
                }
                break;

        default:
                dev_err(&pdev->dev, "unknown API CMD Chain type\n");
                err = -EINVAL;
                break;
        }

        return err;
}

/**
 * api_cmd - API CMD command
 * @chain: chain for the command
 * @dest: destination node on the card that will receive the command
 * @cmd: command data
 * @cmd_size: the command size
 *
 * Return 0 - Success, negative - Failure
 **/
static int api_cmd(struct hinic_api_cmd_chain *chain,
                   enum hinic_node_id dest, u8 *cmd, u16 cmd_size)
{
        struct hinic_api_cmd_cell_ctxt *ctxt;
        int err;

        down(&chain->sem);
        if (chain_busy(chain)) {
                up(&chain->sem);
                return -EBUSY;
        }

        prepare_cell(chain, dest, cmd, cmd_size);
        cmd_chain_prod_idx_inc(chain);

        wmb();  /* inc pi before issue the command */

        set_prod_idx(chain);    /* issue the command */

        ctxt = &chain->cell_ctxt[chain->prod_idx];

        chain->curr_node = ctxt->cell_vaddr;

        err = wait_for_api_cmd_completion(chain);

        up(&chain->sem);
        return err;
}

/**
 * hinic_api_cmd_write - Write API CMD command
 * @chain: chain for write command
 * @dest: destination node on the card that will receive the command
 * @cmd: command data
 * @size: the command size
 *
 * Return 0 - Success, negative - Failure
 **/
int hinic_api_cmd_write(struct hinic_api_cmd_chain *chain,
                        enum hinic_node_id dest, u8 *cmd, u16 size)
{
        /* Verify the chain type */
        if (chain->chain_type == HINIC_API_CMD_WRITE_TO_MGMT_CPU)
                return api_cmd(chain, dest, cmd, size);

        return -EINVAL;
}

/**
 * api_cmd_hw_restart - restart the chain in the HW
 * @chain: the API CMD specific chain to restart
 *
 * Return 0 - Success, negative - Failure
 **/
static int api_cmd_hw_restart(struct hinic_api_cmd_chain *chain)
{
        struct hinic_hwif *hwif = chain->hwif;
        int err = -ETIMEDOUT;
        unsigned long end;
        u32 reg_addr, val;

        /* Read Modify Write */
        reg_addr = HINIC_CSR_API_CMD_CHAIN_REQ_ADDR(chain->chain_type);
        val = hinic_hwif_read_reg(hwif, reg_addr);

        val = HINIC_API_CMD_CHAIN_REQ_CLEAR(val, RESTART);
        val |= HINIC_API_CMD_CHAIN_REQ_SET(1, RESTART);

        hinic_hwif_write_reg(hwif, reg_addr, val);

        end = jiffies + msecs_to_jiffies(API_CMD_TIMEOUT);
        do {
                val = hinic_hwif_read_reg(hwif, reg_addr);

                if (!HINIC_API_CMD_CHAIN_REQ_GET(val, RESTART)) {
                        err = 0;
                        break;
                }

                msleep(20);
        } while (time_before(jiffies, end));

        return err;
}

/**
 * api_cmd_ctrl_init - set the control register of a chain
 * @chain: the API CMD specific chain to set control register for
 **/
static void api_cmd_ctrl_init(struct hinic_api_cmd_chain *chain)
{
        struct hinic_hwif *hwif = chain->hwif;
        u32 addr, ctrl;
        u16 cell_size;

        /* Read Modify Write */
        addr = HINIC_CSR_API_CMD_CHAIN_CTRL_ADDR(chain->chain_type);

        cell_size = API_CMD_CELL_SIZE_VAL(chain->cell_size);

        ctrl = hinic_hwif_read_reg(hwif, addr);

        ctrl =  HINIC_API_CMD_CHAIN_CTRL_CLEAR(ctrl, RESTART_WB_STAT) &
                HINIC_API_CMD_CHAIN_CTRL_CLEAR(ctrl, XOR_ERR)         &
                HINIC_API_CMD_CHAIN_CTRL_CLEAR(ctrl, AEQE_EN)         &
                HINIC_API_CMD_CHAIN_CTRL_CLEAR(ctrl, XOR_CHK_EN)      &
                HINIC_API_CMD_CHAIN_CTRL_CLEAR(ctrl, CELL_SIZE);

        ctrl |= HINIC_API_CMD_CHAIN_CTRL_SET(1, XOR_ERR)              |
                HINIC_API_CMD_CHAIN_CTRL_SET(XOR_CHK_ALL, XOR_CHK_EN) |
                HINIC_API_CMD_CHAIN_CTRL_SET(cell_size, CELL_SIZE);

        hinic_hwif_write_reg(hwif, addr, ctrl);
}

/**
 * api_cmd_set_status_addr - set the status address of a chain in the HW
 * @chain: the API CMD specific chain to set in HW status address for
 **/
static void api_cmd_set_status_addr(struct hinic_api_cmd_chain *chain)
{
        struct hinic_hwif *hwif = chain->hwif;
        u32 addr, val;

        addr = HINIC_CSR_API_CMD_STATUS_HI_ADDR(chain->chain_type);
        val = upper_32_bits(chain->wb_status_paddr);
        hinic_hwif_write_reg(hwif, addr, val);

        addr = HINIC_CSR_API_CMD_STATUS_LO_ADDR(chain->chain_type);
        val = lower_32_bits(chain->wb_status_paddr);
        hinic_hwif_write_reg(hwif, addr, val);
}

/**
 * api_cmd_set_num_cells - set the number cells of a chain in the HW
 * @chain: the API CMD specific chain to set in HW the number of cells for
 **/
static void api_cmd_set_num_cells(struct hinic_api_cmd_chain *chain)
{
        struct hinic_hwif *hwif = chain->hwif;
        u32 addr, val;

        addr = HINIC_CSR_API_CMD_CHAIN_NUM_CELLS_ADDR(chain->chain_type);
        val  = chain->num_cells;
        hinic_hwif_write_reg(hwif, addr, val);
}

/**
 * api_cmd_head_init - set the head of a chain in the HW
 * @chain: the API CMD specific chain to set in HW the head for
 **/
static void api_cmd_head_init(struct hinic_api_cmd_chain *chain)
{
        struct hinic_hwif *hwif = chain->hwif;
        u32 addr, val;

        addr = HINIC_CSR_API_CMD_CHAIN_HEAD_HI_ADDR(chain->chain_type);
        val = upper_32_bits(chain->head_cell_paddr);
        hinic_hwif_write_reg(hwif, addr, val);

        addr = HINIC_CSR_API_CMD_CHAIN_HEAD_LO_ADDR(chain->chain_type);
        val = lower_32_bits(chain->head_cell_paddr);
        hinic_hwif_write_reg(hwif, addr, val);
}

/**
 * api_cmd_chain_hw_clean - clean the HW
 * @chain: the API CMD specific chain
 **/
static void api_cmd_chain_hw_clean(struct hinic_api_cmd_chain *chain)
{
        struct hinic_hwif *hwif = chain->hwif;
        u32 addr, ctrl;

        addr = HINIC_CSR_API_CMD_CHAIN_CTRL_ADDR(chain->chain_type);

        ctrl = hinic_hwif_read_reg(hwif, addr);
        ctrl = HINIC_API_CMD_CHAIN_CTRL_CLEAR(ctrl, RESTART_WB_STAT) &
               HINIC_API_CMD_CHAIN_CTRL_CLEAR(ctrl, XOR_ERR)         &
               HINIC_API_CMD_CHAIN_CTRL_CLEAR(ctrl, AEQE_EN)         &
               HINIC_API_CMD_CHAIN_CTRL_CLEAR(ctrl, XOR_CHK_EN)      &
               HINIC_API_CMD_CHAIN_CTRL_CLEAR(ctrl, CELL_SIZE);

        hinic_hwif_write_reg(hwif, addr, ctrl);
}

/**
 * api_cmd_chain_hw_init - initialize the chain in the HW
 * @chain: the API CMD specific chain to initialize in HW
 *
 * Return 0 - Success, negative - Failure
 **/
static int api_cmd_chain_hw_init(struct hinic_api_cmd_chain *chain)
{
        struct hinic_hwif *hwif = chain->hwif;
        struct pci_dev *pdev = hwif->pdev;
        int err;

        api_cmd_chain_hw_clean(chain);

        api_cmd_set_status_addr(chain);

        err = api_cmd_hw_restart(chain);
        if (err) {
                dev_err(&pdev->dev, "Failed to restart API CMD HW\n");
                return err;
        }

        api_cmd_ctrl_init(chain);
        api_cmd_set_num_cells(chain);
        api_cmd_head_init(chain);
        return 0;
}

/**
 * free_cmd_buf - free the dma buffer of API CMD command
 * @chain: the API CMD specific chain of the cmd
 * @cell_idx: the cell index of the cmd
 **/
static void free_cmd_buf(struct hinic_api_cmd_chain *chain, int cell_idx)
{
        struct hinic_api_cmd_cell_ctxt *cell_ctxt;
        struct hinic_hwif *hwif = chain->hwif;
        struct pci_dev *pdev = hwif->pdev;

        cell_ctxt = &chain->cell_ctxt[cell_idx];

        dma_free_coherent(&pdev->dev, API_CMD_BUF_SIZE,
                          cell_ctxt->api_cmd_vaddr,
                          cell_ctxt->api_cmd_paddr);
}

/**
 * alloc_cmd_buf - allocate a dma buffer for API CMD command
 * @chain: the API CMD specific chain for the cmd
 * @cell: the cell in the HW for the cmd
 * @cell_idx: the index of the cell
 *
 * Return 0 - Success, negative - Failure
 **/
static int alloc_cmd_buf(struct hinic_api_cmd_chain *chain,
                         struct hinic_api_cmd_cell *cell, int cell_idx)
{
        struct hinic_api_cmd_cell_ctxt *cell_ctxt;
        struct hinic_hwif *hwif = chain->hwif;
        struct pci_dev *pdev = hwif->pdev;
        dma_addr_t cmd_paddr;
        u8 *cmd_vaddr;
        int err = 0;

        cmd_vaddr = dma_alloc_coherent(&pdev->dev, API_CMD_BUF_SIZE,
                                       &cmd_paddr, GFP_KERNEL);
        if (!cmd_vaddr)
                return -ENOMEM;

        cell_ctxt = &chain->cell_ctxt[cell_idx];

        cell_ctxt->api_cmd_vaddr = cmd_vaddr;
        cell_ctxt->api_cmd_paddr = cmd_paddr;

        /* set the cmd DMA address in the cell */
        switch (chain->chain_type) {
        case HINIC_API_CMD_WRITE_TO_MGMT_CPU:
                /* The data in the HW should be in Big Endian Format */
                cell->write.hw_cmd_paddr = cpu_to_be64(cmd_paddr);
                break;

        default:
                dev_err(&pdev->dev, "Unsupported API CMD chain type\n");
                free_cmd_buf(chain, cell_idx);
                err = -EINVAL;
                break;
        }

        return err;
}

/**
 * api_cmd_create_cell - create API CMD cell for specific chain
 * @chain: the API CMD specific chain to create its cell
 * @cell_idx: the index of the cell to create
 * @pre_node: previous cell
 * @node_vaddr: the returned virt addr of the cell
 *
 * Return 0 - Success, negative - Failure
 **/
static int api_cmd_create_cell(struct hinic_api_cmd_chain *chain,
                               int cell_idx,
                               struct hinic_api_cmd_cell *pre_node,
                               struct hinic_api_cmd_cell **node_vaddr)
{
        struct hinic_api_cmd_cell_ctxt *cell_ctxt;
        struct hinic_hwif *hwif = chain->hwif;
        struct pci_dev *pdev = hwif->pdev;
        struct hinic_api_cmd_cell *node;
        dma_addr_t node_paddr;
        int err;

        node = dma_alloc_coherent(&pdev->dev, chain->cell_size, &node_paddr,
                                  GFP_KERNEL);
        if (!node)
                return -ENOMEM;

        node->read.hw_wb_resp_paddr = 0;

        cell_ctxt = &chain->cell_ctxt[cell_idx];
        cell_ctxt->cell_vaddr = node;
        cell_ctxt->cell_paddr = node_paddr;

        if (!pre_node) {
                chain->head_cell_paddr = node_paddr;
                chain->head_node = node;
        } else {
                /* The data in the HW should be in Big Endian Format */
                pre_node->next_cell_paddr = cpu_to_be64(node_paddr);
        }

        switch (chain->chain_type) {
        case HINIC_API_CMD_WRITE_TO_MGMT_CPU:
                err = alloc_cmd_buf(chain, node, cell_idx);
                if (err) {
                        dev_err(&pdev->dev, "Failed to allocate cmd buffer\n");
                        goto err_alloc_cmd_buf;
                }
                break;

        default:
                dev_err(&pdev->dev, "Unsupported API CMD chain type\n");
                err = -EINVAL;
                goto err_alloc_cmd_buf;
        }

        *node_vaddr = node;
        return 0;

err_alloc_cmd_buf:
        dma_free_coherent(&pdev->dev, chain->cell_size, node, node_paddr);
        return err;
}

/**
 * api_cmd_destroy_cell - destroy API CMD cell of specific chain
 * @chain: the API CMD specific chain to destroy its cell
 * @cell_idx: the cell to destroy
 **/
static void api_cmd_destroy_cell(struct hinic_api_cmd_chain *chain,
                                 int cell_idx)
{
        struct hinic_api_cmd_cell_ctxt *cell_ctxt;
        struct hinic_hwif *hwif = chain->hwif;
        struct pci_dev *pdev = hwif->pdev;
        struct hinic_api_cmd_cell *node;
        dma_addr_t node_paddr;
        size_t node_size;

        cell_ctxt = &chain->cell_ctxt[cell_idx];

        node = cell_ctxt->cell_vaddr;
        node_paddr = cell_ctxt->cell_paddr;
        node_size = chain->cell_size;

        if (cell_ctxt->api_cmd_vaddr) {
                switch (chain->chain_type) {
                case HINIC_API_CMD_WRITE_TO_MGMT_CPU:
                        free_cmd_buf(chain, cell_idx);
                        break;
                default:
                        dev_err(&pdev->dev, "Unsupported API CMD chain type\n");
                        break;
                }

                dma_free_coherent(&pdev->dev, node_size, node,
                                  node_paddr);
        }
}

/**
 * api_cmd_destroy_cells - destroy API CMD cells of specific chain
 * @chain: the API CMD specific chain to destroy its cells
 * @num_cells: number of cells to destroy
 **/
static void api_cmd_destroy_cells(struct hinic_api_cmd_chain *chain,
                                  int num_cells)
{
        int cell_idx;

        for (cell_idx = 0; cell_idx < num_cells; cell_idx++)
                api_cmd_destroy_cell(chain, cell_idx);
}

/**
 * api_cmd_create_cells - create API CMD cells for specific chain
 * @chain: the API CMD specific chain
 *
 * Return 0 - Success, negative - Failure
 **/
static int api_cmd_create_cells(struct hinic_api_cmd_chain *chain)
{
        struct hinic_api_cmd_cell *node = NULL, *pre_node = NULL;
        struct hinic_hwif *hwif = chain->hwif;
        struct pci_dev *pdev = hwif->pdev;
        int err, cell_idx;

        for (cell_idx = 0; cell_idx < chain->num_cells; cell_idx++) {
                err = api_cmd_create_cell(chain, cell_idx, pre_node, &node);
                if (err) {
                        dev_err(&pdev->dev, "Failed to create API CMD cell\n");
                        goto err_create_cell;
                }

                pre_node = node;
        }

        /* set the Final node to point on the start */
        node->next_cell_paddr = cpu_to_be64(chain->head_cell_paddr);

        /* set the current node to be the head */
        chain->curr_node = chain->head_node;
        return 0;

err_create_cell:
        api_cmd_destroy_cells(chain, cell_idx);
        return err;
}

/**
 * api_chain_init - initialize API CMD specific chain
 * @chain: the API CMD specific chain to initialize
 * @attr: attributes to set in the chain
 *
 * Return 0 - Success, negative - Failure
 **/
static int api_chain_init(struct hinic_api_cmd_chain *chain,
                          struct hinic_api_cmd_chain_attr *attr)
{
        struct hinic_hwif *hwif = attr->hwif;
        struct pci_dev *pdev = hwif->pdev;
        size_t cell_ctxt_size;

        chain->hwif = hwif;
        chain->chain_type  = attr->chain_type;
        chain->num_cells = attr->num_cells;
        chain->cell_size = attr->cell_size;

        chain->prod_idx  = 0;
        chain->cons_idx  = 0;

        sema_init(&chain->sem, 1);

        cell_ctxt_size = chain->num_cells * sizeof(*chain->cell_ctxt);
        chain->cell_ctxt = devm_kzalloc(&pdev->dev, cell_ctxt_size, GFP_KERNEL);
        if (!chain->cell_ctxt)
                return -ENOMEM;

        chain->wb_status = dma_alloc_coherent(&pdev->dev,
                                              sizeof(*chain->wb_status),
                                              &chain->wb_status_paddr,
                                              GFP_KERNEL);
        if (!chain->wb_status) {
                dev_err(&pdev->dev, "Failed to allocate DMA wb status\n");
                return -ENOMEM;
        }

        return 0;
}

/**
 * api_chain_free - free API CMD specific chain
 * @chain: the API CMD specific chain to free
 **/
static void api_chain_free(struct hinic_api_cmd_chain *chain)
{
        struct hinic_hwif *hwif = chain->hwif;
        struct pci_dev *pdev = hwif->pdev;

        dma_free_coherent(&pdev->dev, sizeof(*chain->wb_status),
                          chain->wb_status, chain->wb_status_paddr);
}

/**
 * api_cmd_create_chain - create API CMD specific chain
 * @attr: attributes to set the chain
 *
 * Return the created chain
 **/
static struct hinic_api_cmd_chain *
        api_cmd_create_chain(struct hinic_api_cmd_chain_attr *attr)
{
        struct hinic_hwif *hwif = attr->hwif;
        struct pci_dev *pdev = hwif->pdev;
        struct hinic_api_cmd_chain *chain;
        int err;

        if (attr->num_cells & (attr->num_cells - 1)) {
                dev_err(&pdev->dev, "Invalid number of cells, must be power of 2\n");
                return ERR_PTR(-EINVAL);
        }

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

        err = api_chain_init(chain, attr);
        if (err) {
                dev_err(&pdev->dev, "Failed to initialize chain\n");
                return ERR_PTR(err);
        }

        err = api_cmd_create_cells(chain);
        if (err) {
                dev_err(&pdev->dev, "Failed to create cells for API CMD chain\n");
                goto err_create_cells;
        }

        err = api_cmd_chain_hw_init(chain);
        if (err) {
                dev_err(&pdev->dev, "Failed to initialize chain HW\n");
                goto err_chain_hw_init;
        }

        return chain;

err_chain_hw_init:
        api_cmd_destroy_cells(chain, chain->num_cells);

err_create_cells:
        api_chain_free(chain);
        return ERR_PTR(err);
}

/**
 * api_cmd_destroy_chain - destroy API CMD specific chain
 * @chain: the API CMD specific chain to destroy
 **/
static void api_cmd_destroy_chain(struct hinic_api_cmd_chain *chain)
{
        api_cmd_chain_hw_clean(chain);
        api_cmd_destroy_cells(chain, chain->num_cells);
        api_chain_free(chain);
}

/**
 * hinic_api_cmd_init - Initialize all the API CMD chains
 * @chain: the API CMD chains that are initialized
 * @hwif: the hardware interface of a pci function device
 *
 * Return 0 - Success, negative - Failure
 **/
int hinic_api_cmd_init(struct hinic_api_cmd_chain **chain,
                       struct hinic_hwif *hwif)
{
        enum hinic_api_cmd_chain_type type, chain_type;
        struct hinic_api_cmd_chain_attr attr;
        struct pci_dev *pdev = hwif->pdev;
        size_t hw_cell_sz;
        int err;

        hw_cell_sz = sizeof(struct hinic_api_cmd_cell);

        attr.hwif = hwif;
        attr.num_cells  = API_CHAIN_NUM_CELLS;
        attr.cell_size  = API_CMD_CELL_SIZE(hw_cell_sz);

        chain_type = HINIC_API_CMD_WRITE_TO_MGMT_CPU;
        for ( ; chain_type < HINIC_API_CMD_MAX; chain_type++) {
                attr.chain_type = chain_type;

                if (chain_type != HINIC_API_CMD_WRITE_TO_MGMT_CPU)
                        continue;

                chain[chain_type] = api_cmd_create_chain(&attr);
                if (IS_ERR(chain[chain_type])) {
                        dev_err(&pdev->dev, "Failed to create chain %d\n",
                                chain_type);
                        err = PTR_ERR(chain[chain_type]);
                        goto err_create_chain;
                }
        }

        return 0;

err_create_chain:
        type = HINIC_API_CMD_WRITE_TO_MGMT_CPU;
        for ( ; type < chain_type; type++) {
                if (type != HINIC_API_CMD_WRITE_TO_MGMT_CPU)
                        continue;

                api_cmd_destroy_chain(chain[type]);
        }

        return err;
}

/**
 * hinic_api_cmd_free - free the API CMD chains
 * @chain: the API CMD chains that are freed
 **/
void hinic_api_cmd_free(struct hinic_api_cmd_chain **chain)
{
        enum hinic_api_cmd_chain_type chain_type;

        chain_type = HINIC_API_CMD_WRITE_TO_MGMT_CPU;
        for ( ; chain_type < HINIC_API_CMD_MAX; chain_type++) {
                if (chain_type != HINIC_API_CMD_WRITE_TO_MGMT_CPU)
                        continue;

                api_cmd_destroy_chain(chain[chain_type]);
        }
}