/*
 * SPI bus driver for the Topcliff PCH used by Intel SoCs
 *
 * Copyright (C) 2011 LAPIS Semiconductor Co., Ltd.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; version 2 of the License.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307, USA.
 */

#include <linux/delay.h>
#include <linux/pci.h>
#include <linux/wait.h>
#include <linux/spi/spi.h>
#include <linux/interrupt.h>
#include <linux/sched.h>
#include <linux/spi/spidev.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/platform_device.h>

#include <linux/dmaengine.h>
#include <linux/pch_dma.h>

/* Register offsets */
#define PCH_SPCR                0x00    /* SPI control register */
#define PCH_SPBRR               0x04    /* SPI baud rate register */
#define PCH_SPSR                0x08    /* SPI status register */
#define PCH_SPDWR               0x0C    /* SPI write data register */
#define PCH_SPDRR               0x10    /* SPI read data register */
#define PCH_SSNXCR              0x18    /* SSN Expand Control Register */
#define PCH_SRST                0x1C    /* SPI reset register */
#define PCH_ADDRESS_SIZE        0x20

#define PCH_SPSR_TFD            0x000007C0
#define PCH_SPSR_RFD            0x0000F800

#define PCH_READABLE(x)         (((x) & PCH_SPSR_RFD)>>11)
#define PCH_WRITABLE(x)         (((x) & PCH_SPSR_TFD)>>6)

#define PCH_RX_THOLD            7
#define PCH_RX_THOLD_MAX        15

#define PCH_TX_THOLD            2

#define PCH_MAX_BAUDRATE        5000000
#define PCH_MAX_FIFO_DEPTH      16

#define STATUS_RUNNING          1
#define STATUS_EXITING          2
#define PCH_SLEEP_TIME          10

#define SSN_LOW                 0x02U
#define SSN_HIGH                0x03U
#define SSN_NO_CONTROL          0x00U
#define PCH_MAX_CS              0xFF
#define PCI_DEVICE_ID_GE_SPI    0x8816

#define SPCR_SPE_BIT            (1 << 0)
#define SPCR_MSTR_BIT           (1 << 1)
#define SPCR_LSBF_BIT           (1 << 4)
#define SPCR_CPHA_BIT           (1 << 5)
#define SPCR_CPOL_BIT           (1 << 6)
#define SPCR_TFIE_BIT           (1 << 8)
#define SPCR_RFIE_BIT           (1 << 9)
#define SPCR_FIE_BIT            (1 << 10)
#define SPCR_ORIE_BIT           (1 << 11)
#define SPCR_MDFIE_BIT          (1 << 12)
#define SPCR_FICLR_BIT          (1 << 24)
#define SPSR_TFI_BIT            (1 << 0)
#define SPSR_RFI_BIT            (1 << 1)
#define SPSR_FI_BIT             (1 << 2)
#define SPSR_ORF_BIT            (1 << 3)
#define SPBRR_SIZE_BIT          (1 << 10)

#define PCH_ALL                 (SPCR_TFIE_BIT|SPCR_RFIE_BIT|SPCR_FIE_BIT|\
                                SPCR_ORIE_BIT|SPCR_MDFIE_BIT)

#define SPCR_RFIC_FIELD         20
#define SPCR_TFIC_FIELD         16

#define MASK_SPBRR_SPBR_BITS    ((1 << 10) - 1)
#define MASK_RFIC_SPCR_BITS     (0xf << SPCR_RFIC_FIELD)
#define MASK_TFIC_SPCR_BITS     (0xf << SPCR_TFIC_FIELD)

#define PCH_CLOCK_HZ            50000000
#define PCH_MAX_SPBR            1023

/* Definition for ML7213/ML7223/ML7831 by LAPIS Semiconductor */
#define PCI_VENDOR_ID_ROHM              0x10DB
#define PCI_DEVICE_ID_ML7213_SPI        0x802c
#define PCI_DEVICE_ID_ML7223_SPI        0x800F
#define PCI_DEVICE_ID_ML7831_SPI        0x8816

/*
 * Set the number of SPI instance max
 * Intel EG20T PCH :            1ch
 * LAPIS Semiconductor ML7213 IOH :     2ch
 * LAPIS Semiconductor ML7223 IOH :     1ch
 * LAPIS Semiconductor ML7831 IOH :     1ch
*/
#define PCH_SPI_MAX_DEV                 2

#define PCH_BUF_SIZE            4096
#define PCH_DMA_TRANS_SIZE      12

static int use_dma = 1;

struct pch_spi_dma_ctrl {
        struct dma_async_tx_descriptor  *desc_tx;
        struct dma_async_tx_descriptor  *desc_rx;
        struct pch_dma_slave            param_tx;
        struct pch_dma_slave            param_rx;
        struct dma_chan         *chan_tx;
        struct dma_chan         *chan_rx;
        struct scatterlist              *sg_tx_p;
        struct scatterlist              *sg_rx_p;
        struct scatterlist              sg_tx;
        struct scatterlist              sg_rx;
        int                             nent;
        void                            *tx_buf_virt;
        void                            *rx_buf_virt;
        dma_addr_t                      tx_buf_dma;
        dma_addr_t                      rx_buf_dma;
};
/**
 * struct pch_spi_data - Holds the SPI channel specific details
 * @io_remap_addr:              The remapped PCI base address
 * @master:                     Pointer to the SPI master structure
 * @work:                       Reference to work queue handler
 * @wk:                         Workqueue for carrying out execution of the
 *                              requests
 * @wait:                       Wait queue for waking up upon receiving an
 *                              interrupt.
 * @transfer_complete:          Status of SPI Transfer
 * @bcurrent_msg_processing:    Status flag for message processing
 * @lock:                       Lock for protecting this structure
 * @queue:                      SPI Message queue
 * @status:                     Status of the SPI driver
 * @bpw_len:                    Length of data to be transferred in bits per
 *                              word
 * @transfer_active:            Flag showing active transfer
 * @tx_index:                   Transmit data count; for bookkeeping during
 *                              transfer
 * @rx_index:                   Receive data count; for bookkeeping during
 *                              transfer
 * @tx_buff:                    Buffer for data to be transmitted
 * @rx_index:                   Buffer for Received data
 * @n_curnt_chip:               The chip number that this SPI driver currently
 *                              operates on
 * @current_chip:               Reference to the current chip that this SPI
 *                              driver currently operates on
 * @current_msg:                The current message that this SPI driver is
 *                              handling
 * @cur_trans:                  The current transfer that this SPI driver is
 *                              handling
 * @board_dat:                  Reference to the SPI device data structure
 * @plat_dev:                   platform_device structure
 * @ch:                         SPI channel number
 * @irq_reg_sts:                Status of IRQ registration
 */
struct pch_spi_data {
        void __iomem *io_remap_addr;
        unsigned long io_base_addr;
        struct spi_master *master;
        struct work_struct work;
        struct workqueue_struct *wk;
        wait_queue_head_t wait;
        u8 transfer_complete;
        u8 bcurrent_msg_processing;
        spinlock_t lock;
        struct list_head queue;
        u8 status;
        u32 bpw_len;
        u8 transfer_active;
        u32 tx_index;
        u32 rx_index;
        u16 *pkt_tx_buff;
        u16 *pkt_rx_buff;
        u8 n_curnt_chip;
        struct spi_device *current_chip;
        struct spi_message *current_msg;
        struct spi_transfer *cur_trans;
        struct pch_spi_board_data *board_dat;
        struct platform_device  *plat_dev;
        int ch;
        struct pch_spi_dma_ctrl dma;
        int use_dma;
        u8 irq_reg_sts;
        int save_total_len;
};

/**
 * struct pch_spi_board_data - Holds the SPI device specific details
 * @pdev:               Pointer to the PCI device
 * @suspend_sts:        Status of suspend
 * @num:                The number of SPI device instance
 */
struct pch_spi_board_data {
        struct pci_dev *pdev;
        u8 suspend_sts;
        int num;
};

struct pch_pd_dev_save {
        int num;
        struct platform_device *pd_save[PCH_SPI_MAX_DEV];
        struct pch_spi_board_data *board_dat;
};

static DEFINE_PCI_DEVICE_TABLE(pch_spi_pcidev_id) = {
        { PCI_VDEVICE(INTEL, PCI_DEVICE_ID_GE_SPI),    1, },
        { PCI_VDEVICE(ROHM, PCI_DEVICE_ID_ML7213_SPI), 2, },
        { PCI_VDEVICE(ROHM, PCI_DEVICE_ID_ML7223_SPI), 1, },
        { PCI_VDEVICE(ROHM, PCI_DEVICE_ID_ML7831_SPI), 1, },
        { }
};

/**
 * pch_spi_writereg() - Performs  register writes
 * @master:     Pointer to struct spi_master.
 * @idx:        Register offset.
 * @val:        Value to be written to register.
 */
static inline void pch_spi_writereg(struct spi_master *master, int idx, u32 val)
{
        struct pch_spi_data *data = spi_master_get_devdata(master);
        iowrite32(val, (data->io_remap_addr + idx));
}

/**
 * pch_spi_readreg() - Performs register reads
 * @master:     Pointer to struct spi_master.
 * @idx:        Register offset.
 */
static inline u32 pch_spi_readreg(struct spi_master *master, int idx)
{
        struct pch_spi_data *data = spi_master_get_devdata(master);
        return ioread32(data->io_remap_addr + idx);
}

static inline void pch_spi_setclr_reg(struct spi_master *master, int idx,
                                      u32 set, u32 clr)
{
        u32 tmp = pch_spi_readreg(master, idx);
        tmp = (tmp & ~clr) | set;
        pch_spi_writereg(master, idx, tmp);
}

static void pch_spi_set_master_mode(struct spi_master *master)
{
        pch_spi_setclr_reg(master, PCH_SPCR, SPCR_MSTR_BIT, 0);
}

/**
 * pch_spi_clear_fifo() - Clears the Transmit and Receive FIFOs
 * @master:     Pointer to struct spi_master.
 */
static void pch_spi_clear_fifo(struct spi_master *master)
{
        pch_spi_setclr_reg(master, PCH_SPCR, SPCR_FICLR_BIT, 0);
        pch_spi_setclr_reg(master, PCH_SPCR, 0, SPCR_FICLR_BIT);
}

static void pch_spi_handler_sub(struct pch_spi_data *data, u32 reg_spsr_val,
                                void __iomem *io_remap_addr)
{
        u32 n_read, tx_index, rx_index, bpw_len;
        u16 *pkt_rx_buffer, *pkt_tx_buff;
        int read_cnt;
        u32 reg_spcr_val;
        void __iomem *spsr;
        void __iomem *spdrr;
        void __iomem *spdwr;

        spsr = io_remap_addr + PCH_SPSR;
        iowrite32(reg_spsr_val, spsr);

        if (data->transfer_active) {
                rx_index = data->rx_index;
                tx_index = data->tx_index;
                bpw_len = data->bpw_len;
                pkt_rx_buffer = data->pkt_rx_buff;
                pkt_tx_buff = data->pkt_tx_buff;

                spdrr = io_remap_addr + PCH_SPDRR;
                spdwr = io_remap_addr + PCH_SPDWR;

                n_read = PCH_READABLE(reg_spsr_val);

                for (read_cnt = 0; (read_cnt < n_read); read_cnt++) {
                        pkt_rx_buffer[rx_index++] = ioread32(spdrr);
                        if (tx_index < bpw_len)
                                iowrite32(pkt_tx_buff[tx_index++], spdwr);
                }

                /* disable RFI if not needed */
                if ((bpw_len - rx_index) <= PCH_MAX_FIFO_DEPTH) {
                        reg_spcr_val = ioread32(io_remap_addr + PCH_SPCR);
                        reg_spcr_val &= ~SPCR_RFIE_BIT; /* disable RFI */

                        /* reset rx threshold */
                        reg_spcr_val &= ~MASK_RFIC_SPCR_BITS;
                        reg_spcr_val |= (PCH_RX_THOLD_MAX << SPCR_RFIC_FIELD);

                        iowrite32(reg_spcr_val, (io_remap_addr + PCH_SPCR));
                }

                /* update counts */
                data->tx_index = tx_index;
                data->rx_index = rx_index;

                /* if transfer complete interrupt */
                if (reg_spsr_val & SPSR_FI_BIT) {
                        if ((tx_index == bpw_len) && (rx_index == tx_index)) {
                                /* disable interrupts */
                                pch_spi_setclr_reg(data->master, PCH_SPCR, 0,
                                                   PCH_ALL);

                                /* transfer is completed;
                                   inform pch_spi_process_messages */
                                data->transfer_complete = true;
                                data->transfer_active = false;
                                wake_up(&data->wait);
                        } else {
                                dev_err(&data->master->dev,
                                        "%s : Transfer is not completed",
                                        __func__);
                        }
                }
        }
}

/**
 * pch_spi_handler() - Interrupt handler
 * @irq:        The interrupt number.
 * @dev_id:     Pointer to struct pch_spi_board_data.
 */
static irqreturn_t pch_spi_handler(int irq, void *dev_id)
{
        u32 reg_spsr_val;
        void __iomem *spsr;
        void __iomem *io_remap_addr;
        irqreturn_t ret = IRQ_NONE;
        struct pch_spi_data *data = dev_id;
        struct pch_spi_board_data *board_dat = data->board_dat;

        if (board_dat->suspend_sts) {
                dev_dbg(&board_dat->pdev->dev,
                        "%s returning due to suspend\n", __func__);
                return IRQ_NONE;
        }

        io_remap_addr = data->io_remap_addr;
        spsr = io_remap_addr + PCH_SPSR;

        reg_spsr_val = ioread32(spsr);

        if (reg_spsr_val & SPSR_ORF_BIT) {
                dev_err(&board_dat->pdev->dev, "%s Over run error\n", __func__);
                if (data->current_msg->complete != 0) {
                        data->transfer_complete = true;
                        data->current_msg->status = -EIO;
                        data->current_msg->complete(data->current_msg->context);
                        data->bcurrent_msg_processing = false;
                        data->current_msg = NULL;
                        data->cur_trans = NULL;
                }
        }

        if (data->use_dma)
                return IRQ_NONE;

        /* Check if the interrupt is for SPI device */
        if (reg_spsr_val & (SPSR_FI_BIT | SPSR_RFI_BIT)) {
                pch_spi_handler_sub(data, reg_spsr_val, io_remap_addr);
                ret = IRQ_HANDLED;
        }

        dev_dbg(&board_dat->pdev->dev, "%s EXIT return value=%d\n",
                __func__, ret);

        return ret;
}

/**
 * pch_spi_set_baud_rate() - Sets SPBR field in SPBRR
 * @master:     Pointer to struct spi_master.
 * @speed_hz:   Baud rate.
 */
static void pch_spi_set_baud_rate(struct spi_master *master, u32 speed_hz)
{
        u32 n_spbr = PCH_CLOCK_HZ / (speed_hz * 2);

        /* if baud rate is less than we can support limit it */
        if (n_spbr > PCH_MAX_SPBR)
                n_spbr = PCH_MAX_SPBR;

        pch_spi_setclr_reg(master, PCH_SPBRR, n_spbr, MASK_SPBRR_SPBR_BITS);
}

/**
 * pch_spi_set_bits_per_word() - Sets SIZE field in SPBRR
 * @master:             Pointer to struct spi_master.
 * @bits_per_word:      Bits per word for SPI transfer.
 */
static void pch_spi_set_bits_per_word(struct spi_master *master,
                                      u8 bits_per_word)
{
        if (bits_per_word == 8)
                pch_spi_setclr_reg(master, PCH_SPBRR, 0, SPBRR_SIZE_BIT);
        else
                pch_spi_setclr_reg(master, PCH_SPBRR, SPBRR_SIZE_BIT, 0);
}

/**
 * pch_spi_setup_transfer() - Configures the PCH SPI hardware for transfer
 * @spi:        Pointer to struct spi_device.
 */
static void pch_spi_setup_transfer(struct spi_device *spi)
{
        u32 flags = 0;

        dev_dbg(&spi->dev, "%s SPBRR content =%x setting baud rate=%d\n",
                __func__, pch_spi_readreg(spi->master, PCH_SPBRR),
                spi->max_speed_hz);
        pch_spi_set_baud_rate(spi->master, spi->max_speed_hz);

        /* set bits per word */
        pch_spi_set_bits_per_word(spi->master, spi->bits_per_word);

        if (!(spi->mode & SPI_LSB_FIRST))
                flags |= SPCR_LSBF_BIT;
        if (spi->mode & SPI_CPOL)
                flags |= SPCR_CPOL_BIT;
        if (spi->mode & SPI_CPHA)
                flags |= SPCR_CPHA_BIT;
        pch_spi_setclr_reg(spi->master, PCH_SPCR, flags,
                           (SPCR_LSBF_BIT | SPCR_CPOL_BIT | SPCR_CPHA_BIT));

        /* Clear the FIFO by toggling  FICLR to 1 and back to 0 */
        pch_spi_clear_fifo(spi->master);
}

/**
 * pch_spi_reset() - Clears SPI registers
 * @master:     Pointer to struct spi_master.
 */
static void pch_spi_reset(struct spi_master *master)
{
        /* write 1 to reset SPI */
        pch_spi_writereg(master, PCH_SRST, 0x1);

        /* clear reset */
        pch_spi_writereg(master, PCH_SRST, 0x0);
}

static int pch_spi_setup(struct spi_device *pspi)
{
        /* check bits per word */
        if (pspi->bits_per_word == 0) {
                pspi->bits_per_word = 8;
                dev_dbg(&pspi->dev, "%s 8 bits per word\n", __func__);
        }

        if ((pspi->bits_per_word != 8) && (pspi->bits_per_word != 16)) {
                dev_err(&pspi->dev, "%s Invalid bits per word\n", __func__);
                return -EINVAL;
        }

        /* Check baud rate setting */
        /* if baud rate of chip is greater than
           max we can support,return error */
        if ((pspi->max_speed_hz) > PCH_MAX_BAUDRATE)
                pspi->max_speed_hz = PCH_MAX_BAUDRATE;

        dev_dbg(&pspi->dev, "%s MODE = %x\n", __func__,
                (pspi->mode) & (SPI_CPOL | SPI_CPHA));

        return 0;
}

static int pch_spi_transfer(struct spi_device *pspi, struct spi_message *pmsg)
{

        struct spi_transfer *transfer;
        struct pch_spi_data *data = spi_master_get_devdata(pspi->master);
        int retval;
        unsigned long flags;

        /* validate spi message and baud rate */
        if (unlikely(list_empty(&pmsg->transfers) == 1)) {
                dev_err(&pspi->dev, "%s list empty\n", __func__);
                retval = -EINVAL;
                goto err_out;
        }

        if (unlikely(pspi->max_speed_hz == 0)) {
                dev_err(&pspi->dev, "%s pch_spi_transfer maxspeed=%d\n",
                        __func__, pspi->max_speed_hz);
                retval = -EINVAL;
                goto err_out;
        }

        dev_dbg(&pspi->dev, "%s Transfer List not empty. "
                "Transfer Speed is set.\n", __func__);

        spin_lock_irqsave(&data->lock, flags);
        /* validate Tx/Rx buffers and Transfer length */
        list_for_each_entry(transfer, &pmsg->transfers, transfer_list) {
                if (!transfer->tx_buf && !transfer->rx_buf) {
                        dev_err(&pspi->dev,
                                "%s Tx and Rx buffer NULL\n", __func__);
                        retval = -EINVAL;
                        goto err_return_spinlock;
                }

                if (!transfer->len) {
                        dev_err(&pspi->dev, "%s Transfer length invalid\n",
                                __func__);
                        retval = -EINVAL;
                        goto err_return_spinlock;
                }

                dev_dbg(&pspi->dev, "%s Tx/Rx buffer valid. Transfer length"
                        " valid\n", __func__);

                /* if baud rate has been specified validate the same */
                if (transfer->speed_hz > PCH_MAX_BAUDRATE)
                        transfer->speed_hz = PCH_MAX_BAUDRATE;

                /* if bits per word has been specified validate the same */
                if (transfer->bits_per_word) {
                        if ((transfer->bits_per_word != 8)
                            && (transfer->bits_per_word != 16)) {
                                retval = -EINVAL;
                                dev_err(&pspi->dev,
                                        "%s Invalid bits per word\n", __func__);
                                goto err_return_spinlock;
                        }
                }
        }
        spin_unlock_irqrestore(&data->lock, flags);

        /* We won't process any messages if we have been asked to terminate */
        if (data->status == STATUS_EXITING) {
                dev_err(&pspi->dev, "%s status = STATUS_EXITING.\n", __func__);
                retval = -ESHUTDOWN;
                goto err_out;
        }

        /* If suspended ,return -EINVAL */
        if (data->board_dat->suspend_sts) {
                dev_err(&pspi->dev, "%s suspend; returning EINVAL\n", __func__);
                retval = -EINVAL;
                goto err_out;
        }

        /* set status of message */
        pmsg->actual_length = 0;
        dev_dbg(&pspi->dev, "%s - pmsg->status =%d\n", __func__, pmsg->status);

        pmsg->status = -EINPROGRESS;
        spin_lock_irqsave(&data->lock, flags);
        /* add message to queue */
        list_add_tail(&pmsg->queue, &data->queue);
        spin_unlock_irqrestore(&data->lock, flags);

        dev_dbg(&pspi->dev, "%s - Invoked list_add_tail\n", __func__);

        /* schedule work queue to run */
        queue_work(data->wk, &data->work);
        dev_dbg(&pspi->dev, "%s - Invoked queue work\n", __func__);

        retval = 0;

err_out:
        dev_dbg(&pspi->dev, "%s RETURN=%d\n", __func__, retval);
        return retval;
err_return_spinlock:
        dev_dbg(&pspi->dev, "%s RETURN=%d\n", __func__, retval);
        spin_unlock_irqrestore(&data->lock, flags);
        return retval;
}

static inline void pch_spi_select_chip(struct pch_spi_data *data,
                                       struct spi_device *pspi)
{
        if (data->current_chip != NULL) {
                if (pspi->chip_select != data->n_curnt_chip) {
                        dev_dbg(&pspi->dev, "%s : different slave\n", __func__);
                        data->current_chip = NULL;
                }
        }

        data->current_chip = pspi;

        data->n_curnt_chip = data->current_chip->chip_select;

        dev_dbg(&pspi->dev, "%s :Invoking pch_spi_setup_transfer\n", __func__);
        pch_spi_setup_transfer(pspi);
}

static void pch_spi_set_tx(struct pch_spi_data *data, int *bpw)
{
        int size;
        u32 n_writes;
        int j;
        struct spi_message *pmsg;
        const u8 *tx_buf;
        const u16 *tx_sbuf;

        /* set baud rate if needed */
        if (data->cur_trans->speed_hz) {
                dev_dbg(&data->master->dev, "%s:setting baud rate\n", __func__);
                pch_spi_set_baud_rate(data->master, data->cur_trans->speed_hz);
        }

        /* set bits per word if needed */
        if (data->cur_trans->bits_per_word &&
            (data->current_msg->spi->bits_per_word != data->cur_trans->bits_per_word)) {
                dev_dbg(&data->master->dev, "%s:set bits per word\n", __func__);
                pch_spi_set_bits_per_word(data->master,
                                          data->cur_trans->bits_per_word);
                *bpw = data->cur_trans->bits_per_word;
        } else {
                *bpw = data->current_msg->spi->bits_per_word;
        }

        /* reset Tx/Rx index */
        data->tx_index = 0;
        data->rx_index = 0;

        data->bpw_len = data->cur_trans->len / (*bpw / 8);

        /* find alloc size */
        size = data->cur_trans->len * sizeof(*data->pkt_tx_buff);

        /* allocate memory for pkt_tx_buff & pkt_rx_buffer */
        data->pkt_tx_buff = kzalloc(size, GFP_KERNEL);
        if (data->pkt_tx_buff != NULL) {
                data->pkt_rx_buff = kzalloc(size, GFP_KERNEL);
                if (!data->pkt_rx_buff)
                        kfree(data->pkt_tx_buff);
        }

        if (!data->pkt_rx_buff) {
                /* flush queue and set status of all transfers to -ENOMEM */
                dev_err(&data->master->dev, "%s :kzalloc failed\n", __func__);
                list_for_each_entry(pmsg, data->queue.next, queue) {
                        pmsg->status = -ENOMEM;

                        if (pmsg->complete != 0)
                                pmsg->complete(pmsg->context);

                        /* delete from queue */
                        list_del_init(&pmsg->queue);
                }
                return;
        }

        /* copy Tx Data */
        if (data->cur_trans->tx_buf != NULL) {
                if (*bpw == 8) {
                        tx_buf = data->cur_trans->tx_buf;
                        for (j = 0; j < data->bpw_len; j++)
                                data->pkt_tx_buff[j] = *tx_buf++;
                } else {
                        tx_sbuf = data->cur_trans->tx_buf;
                        for (j = 0; j < data->bpw_len; j++)
                                data->pkt_tx_buff[j] = *tx_sbuf++;
                }
        }

        /* if len greater than PCH_MAX_FIFO_DEPTH, write 16,else len bytes */
        n_writes = data->bpw_len;
        if (n_writes > PCH_MAX_FIFO_DEPTH)
                n_writes = PCH_MAX_FIFO_DEPTH;

        dev_dbg(&data->master->dev, "\n%s:Pulling down SSN low - writing "
                "0x2 to SSNXCR\n", __func__);
        pch_spi_writereg(data->master, PCH_SSNXCR, SSN_LOW);

        for (j = 0; j < n_writes; j++)
                pch_spi_writereg(data->master, PCH_SPDWR, data->pkt_tx_buff[j]);

        /* update tx_index */
        data->tx_index = j;

        /* reset transfer complete flag */
        data->transfer_complete = false;
        data->transfer_active = true;
}

static void pch_spi_nomore_transfer(struct pch_spi_data *data)
{
        struct spi_message *pmsg;
        dev_dbg(&data->master->dev, "%s called\n", __func__);
        /* Invoke complete callback
         * [To the spi core..indicating end of transfer] */
        data->current_msg->status = 0;

        if (data->current_msg->complete != 0) {
                dev_dbg(&data->master->dev,
                        "%s:Invoking callback of SPI core\n", __func__);
                data->current_msg->complete(data->current_msg->context);
        }

        /* update status in global variable */
        data->bcurrent_msg_processing = false;

        dev_dbg(&data->master->dev,
                "%s:data->bcurrent_msg_processing = false\n", __func__);

        data->current_msg = NULL;
        data->cur_trans = NULL;

        /* check if we have items in list and not suspending
         * return 1 if list empty */
        if ((list_empty(&data->queue) == 0) &&
            (!data->board_dat->suspend_sts) &&
            (data->status != STATUS_EXITING)) {
                /* We have some more work to do (either there is more tranint
                 * bpw;sfer requests in the current message or there are
                 *more messages)
                 */
                dev_dbg(&data->master->dev, "%s:Invoke queue_work\n", __func__);
                queue_work(data->wk, &data->work);
        } else if (data->board_dat->suspend_sts ||
                   data->status == STATUS_EXITING) {
                dev_dbg(&data->master->dev,
                        "%s suspend/remove initiated, flushing queue\n",
                        __func__);
                list_for_each_entry(pmsg, data->queue.next, queue) {
                        pmsg->status = -EIO;

                        if (pmsg->complete)
                                pmsg->complete(pmsg->context);

                        /* delete from queue */
                        list_del_init(&pmsg->queue);
                }
        }
}

static void pch_spi_set_ir(struct pch_spi_data *data)
{
        /* enable interrupts, set threshold, enable SPI */
        if ((data->bpw_len) > PCH_MAX_FIFO_DEPTH)
                /* set receive threshold to PCH_RX_THOLD */
                pch_spi_setclr_reg(data->master, PCH_SPCR,
                                   PCH_RX_THOLD << SPCR_RFIC_FIELD |
                                   SPCR_FIE_BIT | SPCR_RFIE_BIT |
                                   SPCR_ORIE_BIT | SPCR_SPE_BIT,
                                   MASK_RFIC_SPCR_BITS | PCH_ALL);
        else
                /* set receive threshold to maximum */
                pch_spi_setclr_reg(data->master, PCH_SPCR,
                                   PCH_RX_THOLD_MAX << SPCR_RFIC_FIELD |
                                   SPCR_FIE_BIT | SPCR_ORIE_BIT |
                                   SPCR_SPE_BIT,
                                   MASK_RFIC_SPCR_BITS | PCH_ALL);

        /* Wait until the transfer completes; go to sleep after
                                 initiating the transfer. */
        dev_dbg(&data->master->dev,
                "%s:waiting for transfer to get over\n", __func__);

        wait_event_interruptible(data->wait, data->transfer_complete);

        /* clear all interrupts */
        pch_spi_writereg(data->master, PCH_SPSR,
                         pch_spi_readreg(data->master, PCH_SPSR));
        /* Disable interrupts and SPI transfer */
        pch_spi_setclr_reg(data->master, PCH_SPCR, 0, PCH_ALL | SPCR_SPE_BIT);
        /* clear FIFO */
        pch_spi_clear_fifo(data->master);
}

static void pch_spi_copy_rx_data(struct pch_spi_data *data, int bpw)
{
        int j;
        u8 *rx_buf;
        u16 *rx_sbuf;

        /* copy Rx Data */
        if (!data->cur_trans->rx_buf)
                return;

        if (bpw == 8) {
                rx_buf = data->cur_trans->rx_buf;
                for (j = 0; j < data->bpw_len; j++)
                        *rx_buf++ = data->pkt_rx_buff[j] & 0xFF;
        } else {
                rx_sbuf = data->cur_trans->rx_buf;
                for (j = 0; j < data->bpw_len; j++)
                        *rx_sbuf++ = data->pkt_rx_buff[j];
        }
}

static void pch_spi_copy_rx_data_for_dma(struct pch_spi_data *data, int bpw)
{
        int j;
        u8 *rx_buf;
        u16 *rx_sbuf;
        const u8 *rx_dma_buf;
        const u16 *rx_dma_sbuf;

        /* copy Rx Data */
        if (!data->cur_trans->rx_buf)
                return;

        if (bpw == 8) {
                rx_buf = data->cur_trans->rx_buf;
                rx_dma_buf = data->dma.rx_buf_virt;
                for (j = 0; j < data->bpw_len; j++)
                        *rx_buf++ = *rx_dma_buf++ & 0xFF;
                data->cur_trans->rx_buf = rx_buf;
        } else {
                rx_sbuf = data->cur_trans->rx_buf;
                rx_dma_sbuf = data->dma.rx_buf_virt;
                for (j = 0; j < data->bpw_len; j++)
                        *rx_sbuf++ = *rx_dma_sbuf++;
                data->cur_trans->rx_buf = rx_sbuf;
        }
}

static int pch_spi_start_transfer(struct pch_spi_data *data)
{
        struct pch_spi_dma_ctrl *dma;
        unsigned long flags;
        int rtn;

        dma = &data->dma;

        spin_lock_irqsave(&data->lock, flags);

        /* disable interrupts, SPI set enable */
        pch_spi_setclr_reg(data->master, PCH_SPCR, SPCR_SPE_BIT, PCH_ALL);

        spin_unlock_irqrestore(&data->lock, flags);

        /* Wait until the transfer completes; go to sleep after
                                 initiating the transfer. */
        dev_dbg(&data->master->dev,
                "%s:waiting for transfer to get over\n", __func__);
        rtn = wait_event_interruptible_timeout(data->wait,
                                               data->transfer_complete,
                                               msecs_to_jiffies(2 * HZ));
        if (!rtn)
                dev_err(&data->master->dev,
                        "%s wait-event timeout\n", __func__);

        dma_sync_sg_for_cpu(&data->master->dev, dma->sg_rx_p, dma->nent,
                            DMA_FROM_DEVICE);

        dma_sync_sg_for_cpu(&data->master->dev, dma->sg_tx_p, dma->nent,
                            DMA_FROM_DEVICE);
        memset(data->dma.tx_buf_virt, 0, PAGE_SIZE);

        async_tx_ack(dma->desc_rx);
        async_tx_ack(dma->desc_tx);
        kfree(dma->sg_tx_p);
        kfree(dma->sg_rx_p);

        spin_lock_irqsave(&data->lock, flags);

        /* clear fifo threshold, disable interrupts, disable SPI transfer */
        pch_spi_setclr_reg(data->master, PCH_SPCR, 0,
                           MASK_RFIC_SPCR_BITS | MASK_TFIC_SPCR_BITS | PCH_ALL |
                           SPCR_SPE_BIT);
        /* clear all interrupts */
        pch_spi_writereg(data->master, PCH_SPSR,
                         pch_spi_readreg(data->master, PCH_SPSR));
        /* clear FIFO */
        pch_spi_clear_fifo(data->master);

        spin_unlock_irqrestore(&data->lock, flags);

        return rtn;
}

static void pch_dma_rx_complete(void *arg)
{
        struct pch_spi_data *data = arg;

        /* transfer is completed;inform pch_spi_process_messages_dma */
        data->transfer_complete = true;
        wake_up_interruptible(&data->wait);
}

static bool pch_spi_filter(struct dma_chan *chan, void *slave)
{
        struct pch_dma_slave *param = slave;

        if ((chan->chan_id == param->chan_id) &&
            (param->dma_dev == chan->device->dev)) {
                chan->private = param;
                return true;
        } else {
                return false;
        }
}

static void pch_spi_request_dma(struct pch_spi_data *data, int bpw)
{
        dma_cap_mask_t mask;
        struct dma_chan *chan;
        struct pci_dev *dma_dev;
        struct pch_dma_slave *param;
        struct pch_spi_dma_ctrl *dma;
        unsigned int width;

        if (bpw == 8)
                width = PCH_DMA_WIDTH_1_BYTE;
        else
                width = PCH_DMA_WIDTH_2_BYTES;

        dma = &data->dma;
        dma_cap_zero(mask);
        dma_cap_set(DMA_SLAVE, mask);

        /* Get DMA's dev information */
        dma_dev = pci_get_bus_and_slot(data->board_dat->pdev->bus->number,
                                       PCI_DEVFN(12, 0));

        /* Set Tx DMA */
        param = &dma->param_tx;
        param->dma_dev = &dma_dev->dev;
        param->chan_id = data->master->bus_num * 2; /* Tx = 0, 2 */
        param->tx_reg = data->io_base_addr + PCH_SPDWR;
        param->width = width;
        chan = dma_request_channel(mask, pch_spi_filter, param);
        if (!chan) {
                dev_err(&data->master->dev,
                        "ERROR: dma_request_channel FAILS(Tx)\n");
                data->use_dma = 0;
                return;
        }
        dma->chan_tx = chan;

        /* Set Rx DMA */
        param = &dma->param_rx;
        param->dma_dev = &dma_dev->dev;
        param->chan_id = data->master->bus_num * 2 + 1; /* Rx = Tx + 1 */
        param->rx_reg = data->io_base_addr + PCH_SPDRR;
        param->width = width;
        chan = dma_request_channel(mask, pch_spi_filter, param);
        if (!chan) {
                dev_err(&data->master->dev,
                        "ERROR: dma_request_channel FAILS(Rx)\n");
                dma_release_channel(dma->chan_tx);
                dma->chan_tx = NULL;
                data->use_dma = 0;
                return;
        }
        dma->chan_rx = chan;
}

static void pch_spi_release_dma(struct pch_spi_data *data)
{
        struct pch_spi_dma_ctrl *dma;

        dma = &data->dma;
        if (dma->chan_tx) {
                dma_release_channel(dma->chan_tx);
                dma->chan_tx = NULL;
        }
        if (dma->chan_rx) {
                dma_release_channel(dma->chan_rx);
                dma->chan_rx = NULL;
        }
        return;
}

static void pch_spi_handle_dma(struct pch_spi_data *data, int *bpw)
{
        const u8 *tx_buf;
        const u16 *tx_sbuf;
        u8 *tx_dma_buf;
        u16 *tx_dma_sbuf;
        struct scatterlist *sg;
        struct dma_async_tx_descriptor *desc_tx;
        struct dma_async_tx_descriptor *desc_rx;
        int num;
        int i;
        int size;
        int rem;
        int head;
        unsigned long flags;
        struct pch_spi_dma_ctrl *dma;

        dma = &data->dma;

        /* set baud rate if needed */
        if (data->cur_trans->speed_hz) {
                dev_dbg(&data->master->dev, "%s:setting baud rate\n", __func__);
                spin_lock_irqsave(&data->lock, flags);
                pch_spi_set_baud_rate(data->master, data->cur_trans->speed_hz);
                spin_unlock_irqrestore(&data->lock, flags);
        }

        /* set bits per word if needed */
        if (data->cur_trans->bits_per_word &&
            (data->current_msg->spi->bits_per_word !=
             data->cur_trans->bits_per_word)) {
                dev_dbg(&data->master->dev, "%s:set bits per word\n", __func__);
                spin_lock_irqsave(&data->lock, flags);
                pch_spi_set_bits_per_word(data->master,
                                          data->cur_trans->bits_per_word);
                spin_unlock_irqrestore(&data->lock, flags);
                *bpw = data->cur_trans->bits_per_word;
        } else {
                *bpw = data->current_msg->spi->bits_per_word;
        }
        data->bpw_len = data->cur_trans->len / (*bpw / 8);

        if (data->bpw_len > PCH_BUF_SIZE) {
                data->bpw_len = PCH_BUF_SIZE;
                data->cur_trans->len -= PCH_BUF_SIZE;
        }

        /* copy Tx Data */
        if (data->cur_trans->tx_buf != NULL) {
                if (*bpw == 8) {
                        tx_buf = data->cur_trans->tx_buf;
                        tx_dma_buf = dma->tx_buf_virt;
                        for (i = 0; i < data->bpw_len; i++)
                                *tx_dma_buf++ = *tx_buf++;
                } else {
                        tx_sbuf = data->cur_trans->tx_buf;
                        tx_dma_sbuf = dma->tx_buf_virt;
                        for (i = 0; i < data->bpw_len; i++)
                                *tx_dma_sbuf++ = *tx_sbuf++;
                }
        }

        /* Calculate Rx parameter for DMA transmitting */
        if (data->bpw_len > PCH_DMA_TRANS_SIZE) {
                if (data->bpw_len % PCH_DMA_TRANS_SIZE) {
                        num = data->bpw_len / PCH_DMA_TRANS_SIZE + 1;
                        rem = data->bpw_len % PCH_DMA_TRANS_SIZE;
                } else {
                        num = data->bpw_len / PCH_DMA_TRANS_SIZE;
                        rem = PCH_DMA_TRANS_SIZE;
                }
                size = PCH_DMA_TRANS_SIZE;
        } else {
                num = 1;
                size = data->bpw_len;
                rem = data->bpw_len;
        }
        dev_dbg(&data->master->dev, "%s num=%d size=%d rem=%d\n",
                __func__, num, size, rem);
        spin_lock_irqsave(&data->lock, flags);

        /* set receive fifo threshold and transmit fifo threshold */
        pch_spi_setclr_reg(data->master, PCH_SPCR,
                           ((size - 1) << SPCR_RFIC_FIELD) |
                           (PCH_TX_THOLD << SPCR_TFIC_FIELD),
                           MASK_RFIC_SPCR_BITS | MASK_TFIC_SPCR_BITS);

        spin_unlock_irqrestore(&data->lock, flags);

        /* RX */
        dma->sg_rx_p = kzalloc(sizeof(struct scatterlist)*num, GFP_ATOMIC);
        sg_init_table(dma->sg_rx_p, num); /* Initialize SG table */
        /* offset, length setting */
        sg = dma->sg_rx_p;
        for (i = 0; i < num; i++, sg++) {
                if (i == (num - 2)) {
                        sg->offset = size * i;
                        sg->offset = sg->offset * (*bpw / 8);
                        sg_set_page(sg, virt_to_page(dma->rx_buf_virt), rem,
                                    sg->offset);
                        sg_dma_len(sg) = rem;
                } else if (i == (num - 1)) {
                        sg->offset = size * (i - 1) + rem;
                        sg->offset = sg->offset * (*bpw / 8);
                        sg_set_page(sg, virt_to_page(dma->rx_buf_virt), size,
                                    sg->offset);
                        sg_dma_len(sg) = size;
                } else {
                        sg->offset = size * i;
                        sg->offset = sg->offset * (*bpw / 8);
                        sg_set_page(sg, virt_to_page(dma->rx_buf_virt), size,
                                    sg->offset);
                        sg_dma_len(sg) = size;
                }
                sg_dma_address(sg) = dma->rx_buf_dma + sg->offset;
        }
        sg = dma->sg_rx_p;
        desc_rx = dmaengine_prep_slave_sg(dma->chan_rx, sg,
                                        num, DMA_DEV_TO_MEM,
                                        DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
        if (!desc_rx) {
                dev_err(&data->master->dev, "%s:device_prep_slave_sg Failed\n",
                        __func__);
                return;
        }
        dma_sync_sg_for_device(&data->master->dev, sg, num, DMA_FROM_DEVICE);
        desc_rx->callback = pch_dma_rx_complete;
        desc_rx->callback_param = data;
        dma->nent = num;
        dma->desc_rx = desc_rx;

        /* Calculate Tx parameter for DMA transmitting */
        if (data->bpw_len > PCH_MAX_FIFO_DEPTH) {
                head = PCH_MAX_FIFO_DEPTH - PCH_DMA_TRANS_SIZE;
                if (data->bpw_len % PCH_DMA_TRANS_SIZE > 4) {
                        num = data->bpw_len / PCH_DMA_TRANS_SIZE + 1;
                        rem = data->bpw_len % PCH_DMA_TRANS_SIZE - head;
                } else {
                        num = data->bpw_len / PCH_DMA_TRANS_SIZE;
                        rem = data->bpw_len % PCH_DMA_TRANS_SIZE +
                              PCH_DMA_TRANS_SIZE - head;
                }
                size = PCH_DMA_TRANS_SIZE;
        } else {
                num = 1;
                size = data->bpw_len;
                rem = data->bpw_len;
                head = 0;
        }

        dma->sg_tx_p = kzalloc(sizeof(struct scatterlist)*num, GFP_ATOMIC);
        sg_init_table(dma->sg_tx_p, num); /* Initialize SG table */
        /* offset, length setting */
        sg = dma->sg_tx_p;
        for (i = 0; i < num; i++, sg++) {
                if (i == 0) {
                        sg->offset = 0;
                        sg_set_page(sg, virt_to_page(dma->tx_buf_virt), size + head,
                                    sg->offset);
                        sg_dma_len(sg) = size + head;
                } else if (i == (num - 1)) {
                        sg->offset = head + size * i;
                        sg->offset = sg->offset * (*bpw / 8);
                        sg_set_page(sg, virt_to_page(dma->tx_buf_virt), rem,
                                    sg->offset);
                        sg_dma_len(sg) = rem;
                } else {
                        sg->offset = head + size * i;
                        sg->offset = sg->offset * (*bpw / 8);
                        sg_set_page(sg, virt_to_page(dma->tx_buf_virt), size,
                                    sg->offset);
                        sg_dma_len(sg) = size;
                }
                sg_dma_address(sg) = dma->tx_buf_dma + sg->offset;
        }
        sg = dma->sg_tx_p;
        desc_tx = dmaengine_prep_slave_sg(dma->chan_tx,
                                        sg, num, DMA_MEM_TO_DEV,
                                        DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
        if (!desc_tx) {
                dev_err(&data->master->dev, "%s:device_prep_slave_sg Failed\n",
                        __func__);
                return;
        }
        dma_sync_sg_for_device(&data->master->dev, sg, num, DMA_TO_DEVICE);
        desc_tx->callback = NULL;
        desc_tx->callback_param = data;
        dma->nent = num;
        dma->desc_tx = desc_tx;

        dev_dbg(&data->master->dev, "\n%s:Pulling down SSN low - writing "
                "0x2 to SSNXCR\n", __func__);

        spin_lock_irqsave(&data->lock, flags);
        pch_spi_writereg(data->master, PCH_SSNXCR, SSN_LOW);
        desc_rx->tx_submit(desc_rx);
        desc_tx->tx_submit(desc_tx);
        spin_unlock_irqrestore(&data->lock, flags);

        /* reset transfer complete flag */
        data->transfer_complete = false;
}

static void pch_spi_process_messages(struct work_struct *pwork)
{
        struct spi_message *pmsg;
        struct pch_spi_data *data;
        int bpw;

        data = container_of(pwork, struct pch_spi_data, work);
        dev_dbg(&data->master->dev, "%s data initialized\n", __func__);

        spin_lock(&data->lock);
        /* check if suspend has been initiated;if yes flush queue */
        if (data->board_dat->suspend_sts || (data->status == STATUS_EXITING)) {
                dev_dbg(&data->master->dev, "%s suspend/remove initiated,"
                        "flushing queue\n", __func__);
                list_for_each_entry(pmsg, data->queue.next, queue) {
                        pmsg->status = -EIO;

                        if (pmsg->complete != 0) {
                                spin_unlock(&data->lock);
                                pmsg->complete(pmsg->context);
                                spin_lock(&data->lock);
                        }

                        /* delete from queue */
                        list_del_init(&pmsg->queue);
                }

                spin_unlock(&data->lock);
                return;
        }

        data->bcurrent_msg_processing = true;
        dev_dbg(&data->master->dev,
                "%s Set data->bcurrent_msg_processing= true\n", __func__);

        /* Get the message from the queue and delete it from there. */
        data->current_msg = list_entry(data->queue.next, struct spi_message,
                                        queue);

        list_del_init(&data->current_msg->queue);

        data->current_msg->status = 0;

        pch_spi_select_chip(data, data->current_msg->spi);

        spin_unlock(&data->lock);

        if (data->use_dma)
                pch_spi_request_dma(data,
                                    data->current_msg->spi->bits_per_word);
        pch_spi_writereg(data->master, PCH_SSNXCR, SSN_NO_CONTROL);
        do {
                int cnt;
                /* If we are already processing a message get the next
                transfer structure from the message otherwise retrieve
                the 1st transfer request from the message. */
                spin_lock(&data->lock);
                if (data->cur_trans == NULL) {
                        data->cur_trans =
                                list_entry(data->current_msg->transfers.next,
                                           struct spi_transfer, transfer_list);
                        dev_dbg(&data->master->dev, "%s "
                                ":Getting 1st transfer message\n", __func__);
                } else {
                        data->cur_trans =
                                list_entry(data->cur_trans->transfer_list.next,
                                           struct spi_transfer, transfer_list);
                        dev_dbg(&data->master->dev, "%s "
                                ":Getting next transfer message\n", __func__);
                }
                spin_unlock(&data->lock);

                if (!data->cur_trans->len)
                        goto out;
                cnt = (data->cur_trans->len - 1) / PCH_BUF_SIZE + 1;
                data->save_total_len = data->cur_trans->len;
                if (data->use_dma) {
                        int i;
                        char *save_rx_buf = data->cur_trans->rx_buf;
                        for (i = 0; i < cnt; i ++) {
                                pch_spi_handle_dma(data, &bpw);
                                if (!pch_spi_start_transfer(data)) {
                                        data->transfer_complete = true;
                                        data->current_msg->status = -EIO;
                                        data->current_msg->complete
                                                   (data->current_msg->context);
                                        data->bcurrent_msg_processing = false;
                                        data->current_msg = NULL;
                                        data->cur_trans = NULL;
                                        goto out;
                                }
                                pch_spi_copy_rx_data_for_dma(data, bpw);
                        }
                        data->cur_trans->rx_buf = save_rx_buf;
                } else {
                        pch_spi_set_tx(data, &bpw);
                        pch_spi_set_ir(data);
                        pch_spi_copy_rx_data(data, bpw);
                        kfree(data->pkt_rx_buff);
                        data->pkt_rx_buff = NULL;
                        kfree(data->pkt_tx_buff);
                        data->pkt_tx_buff = NULL;
                }
                /* increment message count */
                data->cur_trans->len = data->save_total_len;
                data->current_msg->actual_length += data->cur_trans->len;

                dev_dbg(&data->master->dev,
                        "%s:data->current_msg->actual_length=%d\n",
                        __func__, data->current_msg->actual_length);

                /* check for delay */
                if (data->cur_trans->delay_usecs) {
                        dev_dbg(&data->master->dev, "%s:"
                                "delay in usec=%d\n", __func__,
                                data->cur_trans->delay_usecs);
                        udelay(data->cur_trans->delay_usecs);
                }

                spin_lock(&data->lock);

                /* No more transfer in this message. */
                if ((data->cur_trans->transfer_list.next) ==
                    &(data->current_msg->transfers)) {
                        pch_spi_nomore_transfer(data);
                }

                spin_unlock(&data->lock);

        } while (data->cur_trans != NULL);

out:
        pch_spi_writereg(data->master, PCH_SSNXCR, SSN_HIGH);
        if (data->use_dma)
                pch_spi_release_dma(data);
}

static void pch_spi_free_resources(struct pch_spi_board_data *board_dat,
                                   struct pch_spi_data *data)
{
        dev_dbg(&board_dat->pdev->dev, "%s ENTRY\n", __func__);

        /* free workqueue */
        if (data->wk != NULL) {
                destroy_workqueue(data->wk);
                data->wk = NULL;
                dev_dbg(&board_dat->pdev->dev,
                        "%s destroy_workqueue invoked successfully\n",
                        __func__);
        }
}

static int pch_spi_get_resources(struct pch_spi_board_data *board_dat,
                                 struct pch_spi_data *data)
{
        int retval = 0;

        dev_dbg(&board_dat->pdev->dev, "%s ENTRY\n", __func__);

        /* create workqueue */
        data->wk = create_singlethread_workqueue(KBUILD_MODNAME);
        if (!data->wk) {
                dev_err(&board_dat->pdev->dev,
                        "%s create_singlet hread_workqueue failed\n", __func__);
                retval = -EBUSY;
                goto err_return;
        }

        /* reset PCH SPI h/w */
        pch_spi_reset(data->master);
        dev_dbg(&board_dat->pdev->dev,
                "%s pch_spi_reset invoked successfully\n", __func__);

        dev_dbg(&board_dat->pdev->dev, "%s data->irq_reg_sts=true\n", __func__);

err_return:
        if (retval != 0) {
                dev_err(&board_dat->pdev->dev,
                        "%s FAIL:invoking pch_spi_free_resources\n", __func__);
                pch_spi_free_resources(board_dat, data);
        }

        dev_dbg(&board_dat->pdev->dev, "%s Return=%d\n", __func__, retval);

        return retval;
}

static void pch_free_dma_buf(struct pch_spi_board_data *board_dat,
                             struct pch_spi_data *data)
{
        struct pch_spi_dma_ctrl *dma;

        dma = &data->dma;
        if (dma->tx_buf_dma)
                dma_free_coherent(&board_dat->pdev->dev, PCH_BUF_SIZE,
                                  dma->tx_buf_virt, dma->tx_buf_dma);
        if (dma->rx_buf_dma)
                dma_free_coherent(&board_dat->pdev->dev, PCH_BUF_SIZE,
                                  dma->rx_buf_virt, dma->rx_buf_dma);
        return;
}

static void pch_alloc_dma_buf(struct pch_spi_board_data *board_dat,
                              struct pch_spi_data *data)
{
        struct pch_spi_dma_ctrl *dma;

        dma = &data->dma;
        /* Get Consistent memory for Tx DMA */
        dma->tx_buf_virt = dma_alloc_coherent(&board_dat->pdev->dev,
                                PCH_BUF_SIZE, &dma->tx_buf_dma, GFP_KERNEL);
        /* Get Consistent memory for Rx DMA */
        dma->rx_buf_virt = dma_alloc_coherent(&board_dat->pdev->dev,
                                PCH_BUF_SIZE, &dma->rx_buf_dma, GFP_KERNEL);
}

static int pch_spi_pd_probe(struct platform_device *plat_dev)
{
        int ret;
        struct spi_master *master;
        struct pch_spi_board_data *board_dat = dev_get_platdata(&plat_dev->dev);
        struct pch_spi_data *data;

        dev_dbg(&plat_dev->dev, "%s:debug\n", __func__);

        master = spi_alloc_master(&board_dat->pdev->dev,
                                  sizeof(struct pch_spi_data));
        if (!master) {
                dev_err(&plat_dev->dev, "spi_alloc_master[%d] failed.\n",
                        plat_dev->id);
                return -ENOMEM;
        }

        data = spi_master_get_devdata(master);
        data->master = master;

        platform_set_drvdata(plat_dev, data);

        /* baseaddress + address offset) */
        data->io_base_addr = pci_resource_start(board_dat->pdev, 1) +
                                         PCH_ADDRESS_SIZE * plat_dev->id;
        data->io_remap_addr = pci_iomap(board_dat->pdev, 1, 0) +
                                         PCH_ADDRESS_SIZE * plat_dev->id;
        if (!data->io_remap_addr) {
                dev_err(&plat_dev->dev, "%s pci_iomap failed\n", __func__);
                ret = -ENOMEM;
                goto err_pci_iomap;
        }

        dev_dbg(&plat_dev->dev, "[ch%d] remap_addr=%p\n",
                plat_dev->id, data->io_remap_addr);

        /* initialize members of SPI master */
        master->num_chipselect = PCH_MAX_CS;
        master->setup = pch_spi_setup;
        master->transfer = pch_spi_transfer;
        master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_LSB_FIRST;

        data->board_dat = board_dat;
        data->plat_dev = plat_dev;
        data->n_curnt_chip = 255;
        data->status = STATUS_RUNNING;
        data->ch = plat_dev->id;
        data->use_dma = use_dma;

        INIT_LIST_HEAD(&data->queue);
        spin_lock_init(&data->lock);
        INIT_WORK(&data->work, pch_spi_process_messages);
        init_waitqueue_head(&data->wait);

        ret = pch_spi_get_resources(board_dat, data);
        if (ret) {
                dev_err(&plat_dev->dev, "%s fail(retval=%d)\n", __func__, ret);
                goto err_spi_get_resources;
        }

        ret = request_irq(board_dat->pdev->irq, pch_spi_handler,
                          IRQF_SHARED, KBUILD_MODNAME, data);
        if (ret) {
                dev_err(&plat_dev->dev,
                        "%s request_irq failed\n", __func__);
                goto err_request_irq;
        }
        data->irq_reg_sts = true;

        pch_spi_set_master_mode(master);

        ret = spi_register_master(master);
        if (ret != 0) {
                dev_err(&plat_dev->dev,
                        "%s spi_register_master FAILED\n", __func__);
                goto err_spi_register_master;
        }

        if (use_dma) {
                dev_info(&plat_dev->dev, "Use DMA for data transfers\n");
                pch_alloc_dma_buf(board_dat, data);
        }

        return 0;

err_spi_register_master:
        free_irq(board_dat->pdev->irq, board_dat);
err_request_irq:
        pch_spi_free_resources(board_dat, data);
err_spi_get_resources:
        pci_iounmap(board_dat->pdev, data->io_remap_addr);
err_pci_iomap:
        spi_master_put(master);

        return ret;
}

static int pch_spi_pd_remove(struct platform_device *plat_dev)
{
        struct pch_spi_board_data *board_dat = dev_get_platdata(&plat_dev->dev);
        struct pch_spi_data *data = platform_get_drvdata(plat_dev);
        int count;
        unsigned long flags;

        dev_dbg(&plat_dev->dev, "%s:[ch%d] irq=%d\n",
                __func__, plat_dev->id, board_dat->pdev->irq);

        if (use_dma)
                pch_free_dma_buf(board_dat, data);

        /* check for any pending messages; no action is taken if the queue
         * is still full; but at least we tried.  Unload anyway */
        count = 500;
        spin_lock_irqsave(&data->lock, flags);
        data->status = STATUS_EXITING;
        while ((list_empty(&data->queue) == 0) && --count) {
                dev_dbg(&board_dat->pdev->dev, "%s :queue not empty\n",
                        __func__);
                spin_unlock_irqrestore(&data->lock, flags);
                msleep(PCH_SLEEP_TIME);
                spin_lock_irqsave(&data->lock, flags);
        }
        spin_unlock_irqrestore(&data->lock, flags);

        pch_spi_free_resources(board_dat, data);
        /* disable interrupts & free IRQ */
        if (data->irq_reg_sts) {
                /* disable interrupts */
                pch_spi_setclr_reg(data->master, PCH_SPCR, 0, PCH_ALL);
                data->irq_reg_sts = false;
                free_irq(board_dat->pdev->irq, data);
        }

        pci_iounmap(board_dat->pdev, data->io_remap_addr);
        spi_unregister_master(data->master);

        return 0;
}
#ifdef CONFIG_PM
static int pch_spi_pd_suspend(struct platform_device *pd_dev,
                              pm_message_t state)
{
        u8 count;
        struct pch_spi_board_data *board_dat = dev_get_platdata(&pd_dev->dev);
        struct pch_spi_data *data = platform_get_drvdata(pd_dev);

        dev_dbg(&pd_dev->dev, "%s ENTRY\n", __func__);

        if (!board_dat) {
                dev_err(&pd_dev->dev,
                        "%s pci_get_drvdata returned NULL\n", __func__);
                return -EFAULT;
        }

        /* check if the current message is processed:
           Only after thats done the transfer will be suspended */
        count = 255;
        while ((--count) > 0) {
                if (!(data->bcurrent_msg_processing))
                        break;
                msleep(PCH_SLEEP_TIME);
        }

        /* Free IRQ */
        if (data->irq_reg_sts) {
                /* disable all interrupts */
                pch_spi_setclr_reg(data->master, PCH_SPCR, 0, PCH_ALL);
                pch_spi_reset(data->master);
                free_irq(board_dat->pdev->irq, data);

                data->irq_reg_sts = false;
                dev_dbg(&pd_dev->dev,
                        "%s free_irq invoked successfully.\n", __func__);
        }

        return 0;
}

static int pch_spi_pd_resume(struct platform_device *pd_dev)
{
        struct pch_spi_board_data *board_dat = dev_get_platdata(&pd_dev->dev);
        struct pch_spi_data *data = platform_get_drvdata(pd_dev);
        int retval;

        if (!board_dat) {
                dev_err(&pd_dev->dev,
                        "%s pci_get_drvdata returned NULL\n", __func__);
                return -EFAULT;
        }

        if (!data->irq_reg_sts) {
                /* register IRQ */
                retval = request_irq(board_dat->pdev->irq, pch_spi_handler,
                                     IRQF_SHARED, KBUILD_MODNAME, data);
                if (retval < 0) {
                        dev_err(&pd_dev->dev,
                                "%s request_irq failed\n", __func__);
                        return retval;
                }

                /* reset PCH SPI h/w */
                pch_spi_reset(data->master);
                pch_spi_set_master_mode(data->master);
                data->irq_reg_sts = true;
        }
        return 0;
}
#else
#define pch_spi_pd_suspend NULL
#define pch_spi_pd_resume NULL
#endif

static struct platform_driver pch_spi_pd_driver = {
        .driver = {
                .name = "pch-spi",
                .owner = THIS_MODULE,
        },
        .probe = pch_spi_pd_probe,
        .remove = pch_spi_pd_remove,
        .suspend = pch_spi_pd_suspend,
        .resume = pch_spi_pd_resume
};

static int pch_spi_probe(struct pci_dev *pdev,
                                   const struct pci_device_id *id)
{
        struct pch_spi_board_data *board_dat;
        struct platform_device *pd_dev = NULL;
        int retval;
        int i;
        struct pch_pd_dev_save *pd_dev_save;

        pd_dev_save = kzalloc(sizeof(struct pch_pd_dev_save), GFP_KERNEL);
        if (!pd_dev_save) {
                dev_err(&pdev->dev, "%s Can't allocate pd_dev_sav\n", __func__);
                return -ENOMEM;
        }

        board_dat = kzalloc(sizeof(struct pch_spi_board_data), GFP_KERNEL);
        if (!board_dat) {
                dev_err(&pdev->dev, "%s Can't allocate board_dat\n", __func__);
                retval = -ENOMEM;
                goto err_no_mem;
        }

        retval = pci_request_regions(pdev, KBUILD_MODNAME);
        if (retval) {
                dev_err(&pdev->dev, "%s request_region failed\n", __func__);
                goto pci_request_regions;
        }

        board_dat->pdev = pdev;
        board_dat->num = id->driver_data;
        pd_dev_save->num = id->driver_data;
        pd_dev_save->board_dat = board_dat;

        retval = pci_enable_device(pdev);
        if (retval) {
                dev_err(&pdev->dev, "%s pci_enable_device failed\n", __func__);
                goto pci_enable_device;
        }

        for (i = 0; i < board_dat->num; i++) {
                pd_dev = platform_device_alloc("pch-spi", i);
                if (!pd_dev) {
                        dev_err(&pdev->dev, "platform_device_alloc failed\n");
                        goto err_platform_device;
                }
                pd_dev_save->pd_save[i] = pd_dev;
                pd_dev->dev.parent = &pdev->dev;

                retval = platform_device_add_data(pd_dev, board_dat,
                                                  sizeof(*board_dat));
                if (retval) {
                        dev_err(&pdev->dev,
                                "platform_device_add_data failed\n");
                        platform_device_put(pd_dev);
                        goto err_platform_device;
                }

                retval = platform_device_add(pd_dev);
                if (retval) {
                        dev_err(&pdev->dev, "platform_device_add failed\n");
                        platform_device_put(pd_dev);
                        goto err_platform_device;
                }
        }

        pci_set_drvdata(pdev, pd_dev_save);

        return 0;

err_platform_device:
        pci_disable_device(pdev);
pci_enable_device:
        pci_release_regions(pdev);
pci_request_regions:
        kfree(board_dat);
err_no_mem:
        kfree(pd_dev_save);

        return retval;
}

static void pch_spi_remove(struct pci_dev *pdev)
{
        int i;
        struct pch_pd_dev_save *pd_dev_save = pci_get_drvdata(pdev);

        dev_dbg(&pdev->dev, "%s ENTRY:pdev=%p\n", __func__, pdev);

        for (i = 0; i < pd_dev_save->num; i++)
                platform_device_unregister(pd_dev_save->pd_save[i]);

        pci_disable_device(pdev);
        pci_release_regions(pdev);
        kfree(pd_dev_save->board_dat);
        kfree(pd_dev_save);
}

#ifdef CONFIG_PM
static int pch_spi_suspend(struct pci_dev *pdev, pm_message_t state)
{
        int retval;
        struct pch_pd_dev_save *pd_dev_save = pci_get_drvdata(pdev);

        dev_dbg(&pdev->dev, "%s ENTRY\n", __func__);

        pd_dev_save->board_dat->suspend_sts = true;

        /* save config space */
        retval = pci_save_state(pdev);
        if (retval == 0) {
                pci_enable_wake(pdev, PCI_D3hot, 0);
                pci_disable_device(pdev);
                pci_set_power_state(pdev, PCI_D3hot);
        } else {
                dev_err(&pdev->dev, "%s pci_save_state failed\n", __func__);
        }

        return retval;
}

static int pch_spi_resume(struct pci_dev *pdev)
{
        int retval;
        struct pch_pd_dev_save *pd_dev_save = pci_get_drvdata(pdev);
        dev_dbg(&pdev->dev, "%s ENTRY\n", __func__);

        pci_set_power_state(pdev, PCI_D0);
        pci_restore_state(pdev);

        retval = pci_enable_device(pdev);
        if (retval < 0) {
                dev_err(&pdev->dev,
                        "%s pci_enable_device failed\n", __func__);
        } else {
                pci_enable_wake(pdev, PCI_D3hot, 0);

                /* set suspend status to false */
                pd_dev_save->board_dat->suspend_sts = false;
        }

        return retval;
}
#else
#define pch_spi_suspend NULL
#define pch_spi_resume NULL

#endif

static struct pci_driver pch_spi_pcidev_driver = {
        .name = "pch_spi",
        .id_table = pch_spi_pcidev_id,
        .probe = pch_spi_probe,
        .remove = pch_spi_remove,
        .suspend = pch_spi_suspend,
        .resume = pch_spi_resume,
};

static int __init pch_spi_init(void)
{
        int ret;
        ret = platform_driver_register(&pch_spi_pd_driver);
        if (ret)
                return ret;

        ret = pci_register_driver(&pch_spi_pcidev_driver);
        if (ret)
                return ret;

        return 0;
}
module_init(pch_spi_init);

static void __exit pch_spi_exit(void)
{
        pci_unregister_driver(&pch_spi_pcidev_driver);
        platform_driver_unregister(&pch_spi_pd_driver);
}
module_exit(pch_spi_exit);

module_param(use_dma, int, 0644);
MODULE_PARM_DESC(use_dma,
                 "to use DMA for data transfers pass 1 else 0; default 1");

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Intel EG20T PCH/LAPIS Semiconductor ML7xxx IOH SPI Driver");