mpt2sas: Fix for system hang when discovery in progress

[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / drivers / spi / spi_topcliff_pch.c

/*
 * SPI bus driver for the Topcliff PCH used by Intel SoCs
 *
 * Copyright (C) 2010 OKI 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>

/* 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_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_MAX_BAUDRATE        5000000
#define PCH_MAX_FIFO_DEPTH      16

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

#define PCH_ADDRESS_SIZE        0x20

#define SSN_LOW                 0x02U
#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 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 SPSR_INT_BITS           0x1F
#define MASK_SPBRR_SPBR_BITS    (~((1 << 10) - 1))
#define MASK_RFIC_SPCR_BITS     (~(0xf << 20))
#define MASK_TFIC_SPCR_BITS     (~(0xf000f << 12))

#define PCH_CLOCK_HZ            50000000
#define PCH_MAX_SPBR            1023


/**
 * 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
 */
struct pch_spi_data {
        void __iomem *io_remap_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 pch_spi_board_data - Holds the SPI device specific details
 * @pdev:               Pointer to the PCI device
 * @irq_reg_sts:        Status of IRQ registration
 * @pci_req_sts:        Status of pci_request_regions
 * @suspend_sts:        Status of suspend
 * @data:               Pointer to SPI channel data structure
 */
struct pch_spi_board_data {
        struct pci_dev *pdev;
        u8 irq_reg_sts;
        u8 pci_req_sts;
        u8 suspend_sts;
        struct pch_spi_data *data;
};

static struct pci_device_id pch_spi_pcidev_id[] = {
        {PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_GE_SPI)},
        {0,}
};

/**
 * 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) &= (~(SPCR_RFIE_BIT))),
                                 (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) {
                /* disable FI & RFI interrupts */
                pch_spi_setclr_reg(data->master, PCH_SPCR, 0,
                                   SPCR_FIE_BIT | SPCR_RFIE_BIT);

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

/**
 * 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;
        struct pch_spi_data *data;
        void __iomem *spsr;
        void __iomem *io_remap_addr;
        irqreturn_t ret = IRQ_NONE;
        struct pch_spi_board_data *board_dat = dev_id;

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

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

        reg_spsr_val = ioread32(spsr);

        /* 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_tranfer 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__);

        /* 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_out;
                }

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

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

                /* if baud rate hs 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_out;
                        }
                }
        }

        spin_lock_irqsave(&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_return_spinlock;
        }

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

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

        pmsg->status = -EINPROGRESS;

        /* add message to queue */
        list_add_tail(&pmsg->queue, &data->queue);
        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_return_spinlock:
        spin_unlock_irqrestore(&data->lock, flags);
err_out:
        dev_dbg(&pspi->dev, "%s RETURN=%d\n", __func__, retval);
        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,
                           struct spi_message **ppmsg)
{
        int size;
        u32 n_writes;
        int j;
        struct spi_message *pmsg;
        const u8 *tx_buf;
        const u16 *tx_sbuf;

        pmsg = *ppmsg;

        /* 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 */
        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,
                                   ~MASK_RFIC_SPCR_BITS);
                /* enable FI and RFI interrupts */
                pch_spi_setclr_reg(data->master, PCH_SPCR,
                                   SPCR_RFIE_BIT | SPCR_FIE_BIT, 0);
        } else {
                /* set receive threshold to maximum */
                pch_spi_setclr_reg(data->master, PCH_SPCR,
                                   PCH_RX_THOLD_MAX << SPCR_TFIC_FIELD,
                                   ~MASK_TFIC_SPCR_BITS);
                /* enable FI interrupt */
                pch_spi_setclr_reg(data->master, PCH_SPCR, SPCR_FIE_BIT, 0);
        }

        dev_dbg(&data->master->dev,
                "%s:invoking pch_spi_set_enable to enable SPI\n", __func__);

        /* SPI set enable */
        pch_spi_setclr_reg(data->current_chip->master, PCH_SPCR, SPCR_SPE_BIT, 0);

        /* 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);

        pch_spi_writereg(data->master, PCH_SSNXCR, SSN_NO_CONTROL);
        dev_dbg(&data->master->dev,
                "%s:no more control over SSN-writing 0 to SSNXCR.", __func__);

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

        /* clear all interrupts */
        pch_spi_writereg(data->master, PCH_SPSR,
                         pch_spi_readreg(data->master, PCH_SPSR));
        /* disable interrupts */
        pch_spi_setclr_reg(data->master, PCH_SPCR, 0, PCH_ALL);
}

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_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);

        do {
                /* 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);

                pch_spi_set_tx(data, &bpw, &pmsg);

                /* Control interrupt*/
                pch_spi_set_ir(data);

                /* Disable SPI transfer */
                pch_spi_setclr_reg(data->current_chip->master, PCH_SPCR, 0,
                                   SPCR_SPE_BIT);

                /* clear FIFO */
                pch_spi_clear_fifo(data->master);

                /* copy Rx Data */
                pch_spi_copy_rx_data(data, bpw);

                /* free memory */
                kfree(data->pkt_rx_buff);
                data->pkt_rx_buff = NULL;

                kfree(data->pkt_tx_buff);
                data->pkt_tx_buff = NULL;

                /* increment message count */
                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, pmsg);
                }

                spin_unlock(&data->lock);

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

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

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

        /* disable interrupts & free IRQ */
        if (board_dat->irq_reg_sts) {
                /* disable interrupts */
                pch_spi_setclr_reg(board_dat->data->master, PCH_SPCR, 0,
                                   PCH_ALL);

                /* free IRQ */
                free_irq(board_dat->pdev->irq, board_dat);

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

                board_dat->irq_reg_sts = false;
        }

        /* unmap PCI base address */
        if (board_dat->data->io_remap_addr != 0) {
                pci_iounmap(board_dat->pdev, board_dat->data->io_remap_addr);

                board_dat->data->io_remap_addr = 0;

                dev_dbg(&board_dat->pdev->dev,
                        "%s pci_iounmap invoked successfully\n", __func__);
        }

        /* release PCI region */
        if (board_dat->pci_req_sts) {
                pci_release_regions(board_dat->pdev);
                dev_dbg(&board_dat->pdev->dev,
                        "%s pci_release_regions invoked successfully\n",
                        __func__);
                board_dat->pci_req_sts = false;
        }
}

static int pch_spi_get_resources(struct pch_spi_board_data *board_dat)
{
        void __iomem *io_remap_addr;
        int retval;
        dev_dbg(&board_dat->pdev->dev, "%s ENTRY\n", __func__);

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

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

        retval = pci_request_regions(board_dat->pdev, KBUILD_MODNAME);
        if (retval != 0) {
                dev_err(&board_dat->pdev->dev,
                        "%s request_region failed\n", __func__);
                goto err_return;
        }

        board_dat->pci_req_sts = true;

        io_remap_addr = pci_iomap(board_dat->pdev, 1, 0);
        if (io_remap_addr == 0) {
                dev_err(&board_dat->pdev->dev,
                        "%s pci_iomap failed\n", __func__);
                retval = -ENOMEM;
                goto err_return;
        }

        /* calculate base address for all channels */
        board_dat->data->io_remap_addr = io_remap_addr;

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

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

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

        board_dat->irq_reg_sts = true;
        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);
        }

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

        return retval;
}

static int pch_spi_probe(struct pci_dev *pdev, const struct pci_device_id *id)
{

        struct spi_master *master;

        struct pch_spi_board_data *board_dat;
        int retval;

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

        /* allocate memory for private data */
        board_dat = kzalloc(sizeof(struct pch_spi_board_data), GFP_KERNEL);
        if (board_dat == NULL) {
                dev_err(&pdev->dev,
                        " %s memory allocation for private data failed\n",
                        __func__);
                retval = -ENOMEM;
                goto err_kmalloc;
        }

        dev_dbg(&pdev->dev,
                "%s memory allocation for private data success\n", __func__);

        /* enable PCI device */
        retval = pci_enable_device(pdev);
        if (retval != 0) {
                dev_err(&pdev->dev, "%s pci_enable_device FAILED\n", __func__);

                goto err_pci_en_device;
        }

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

        board_dat->pdev = pdev;

        /* alllocate memory for SPI master */
        master = spi_alloc_master(&pdev->dev, sizeof(struct pch_spi_data));
        if (master == NULL) {
                retval = -ENOMEM;
                dev_err(&pdev->dev, "%s Fail.\n", __func__);
                goto err_spi_alloc_master;
        }

        dev_dbg(&pdev->dev,
                "%s spi_alloc_master returned non NULL\n", __func__);

        /* initialize members of SPI master */
        master->bus_num = -1;
        master->num_chipselect = PCH_MAX_CS;
        master->setup = pch_spi_setup;
        master->transfer = pch_spi_transfer;
        dev_dbg(&pdev->dev,
                "%s transfer member of SPI master initialized\n", __func__);

        board_dat->data = spi_master_get_devdata(master);

        board_dat->data->master = master;
        board_dat->data->n_curnt_chip = 255;
        board_dat->data->board_dat = board_dat;
        board_dat->data->status = STATUS_RUNNING;

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

        /* allocate resources for PCH SPI */
        retval = pch_spi_get_resources(board_dat);
        if (retval) {
                dev_err(&pdev->dev, "%s fail(retval=%d)\n", __func__, retval);
                goto err_spi_get_resources;
        }

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

        /* save private data in dev */
        pci_set_drvdata(pdev, board_dat);
        dev_dbg(&pdev->dev, "%s invoked pci_set_drvdata\n", __func__);

        /* set master mode */
        pch_spi_set_master_mode(master);
        dev_dbg(&pdev->dev,
                "%s invoked pch_spi_set_master_mode\n", __func__);

        /* Register the controller with the SPI core. */
        retval = spi_register_master(master);
        if (retval != 0) {
                dev_err(&pdev->dev,
                        "%s spi_register_master FAILED\n", __func__);
                goto err_spi_reg_master;
        }

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


        return 0;

err_spi_reg_master:
        spi_unregister_master(master);
err_spi_get_resources:
err_spi_alloc_master:
        spi_master_put(master);
        pci_disable_device(pdev);
err_pci_en_device:
        kfree(board_dat);
err_kmalloc:
        return retval;
}

static void pch_spi_remove(struct pci_dev *pdev)
{
        struct pch_spi_board_data *board_dat = pci_get_drvdata(pdev);
        int count;

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

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

        /* 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(&board_dat->data->lock);
        board_dat->data->status = STATUS_EXITING;
        while ((list_empty(&board_dat->data->queue) == 0) && --count) {
                dev_dbg(&board_dat->pdev->dev, "%s :queue not empty\n",
                        __func__);
                spin_unlock(&board_dat->data->lock);
                msleep(PCH_SLEEP_TIME);
                spin_lock(&board_dat->data->lock);
        }
        spin_unlock(&board_dat->data->lock);

        /* Free resources allocated for PCH SPI */
        pch_spi_free_resources(board_dat);

        spi_unregister_master(board_dat->data->master);

        /* free memory for private data */
        kfree(board_dat);

        pci_set_drvdata(pdev, NULL);

        /* disable PCI device */
        pci_disable_device(pdev);

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

#ifdef CONFIG_PM
static int pch_spi_suspend(struct pci_dev *pdev, pm_message_t state)
{
        u8 count;
        int retval;

        struct pch_spi_board_data *board_dat = pci_get_drvdata(pdev);

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

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

        retval = 0;
        board_dat->suspend_sts = true;

        /* check if the current message is processed:
           Only after thats done the transfer will be suspended */
        count = 255;
        while ((--count) > 0) {
                if (!(board_dat->data->bcurrent_msg_processing)) {
                        dev_dbg(&pdev->dev, "%s board_dat->data->bCurrent_"
                                "msg_processing = false\n", __func__);
                        break;
                } else {
                        dev_dbg(&pdev->dev, "%s board_dat->data->bCurrent_msg_"
                                "processing = true\n", __func__);
                }
                msleep(PCH_SLEEP_TIME);
        }

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

                free_irq(board_dat->pdev->irq, board_dat);

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

        /* save config space */
        retval = pci_save_state(pdev);

        if (retval == 0) {
                dev_dbg(&pdev->dev, "%s pci_save_state returned=%d\n",
                        __func__, retval);
                /* disable PM notifications */
                pci_enable_wake(pdev, PCI_D3hot, 0);
                dev_dbg(&pdev->dev,
                        "%s pci_enable_wake invoked successfully\n", __func__);
                /* disable PCI device */
                pci_disable_device(pdev);
                dev_dbg(&pdev->dev,
                        "%s pci_disable_device invoked successfully\n",
                        __func__);
                /* move device to D3hot  state */
                pci_set_power_state(pdev, PCI_D3hot);
                dev_dbg(&pdev->dev,
                        "%s pci_set_power_state invoked successfully\n",
                        __func__);
        } else {
                dev_err(&pdev->dev, "%s pci_save_state failed\n", __func__);
        }

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

        return retval;
}

static int pch_spi_resume(struct pci_dev *pdev)
{
        int retval;

        struct pch_spi_board_data *board = pci_get_drvdata(pdev);
        dev_dbg(&pdev->dev, "%s ENTRY\n", __func__);

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

        /* move device to DO power state */
        pci_set_power_state(pdev, PCI_D0);

        /* restore state */
        pci_restore_state(pdev);

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

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

                        /* reset PCH SPI h/w */
                        pch_spi_reset(board->data->master);
                        pch_spi_set_master_mode(board->data->master);

                        /* set suspend status to false */
                        board->suspend_sts = false;

                }
        }

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

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

#endif

static struct pci_driver pch_spi_pcidev = {
        .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)
{
        return pci_register_driver(&pch_spi_pcidev);
}
module_init(pch_spi_init);

static void __exit pch_spi_exit(void)
{
        pci_unregister_driver(&pch_spi_pcidev);
}
module_exit(pch_spi_exit);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Topcliff PCH SPI PCI Driver");