/*
 * Copyright (C) 2010 - Maxim Levitsky
 * driver for Ricoh memstick readers
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/freezer.h>
#include <linux/jiffies.h>
#include <linux/interrupt.h>
#include <linux/pci.h>
#include <linux/pci_ids.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/kthread.h>
#include <linux/sched.h>
#include <linux/highmem.h>
#include <asm/byteorder.h>
#include <linux/swab.h>
#include "r592.h"

static bool r592_enable_dma = 1;
static int debug;

static const char *tpc_names[] = {
        "MS_TPC_READ_MG_STATUS",
        "MS_TPC_READ_LONG_DATA",
        "MS_TPC_READ_SHORT_DATA",
        "MS_TPC_READ_REG",
        "MS_TPC_READ_QUAD_DATA",
        "INVALID",
        "MS_TPC_GET_INT",
        "MS_TPC_SET_RW_REG_ADRS",
        "MS_TPC_EX_SET_CMD",
        "MS_TPC_WRITE_QUAD_DATA",
        "MS_TPC_WRITE_REG",
        "MS_TPC_WRITE_SHORT_DATA",
        "MS_TPC_WRITE_LONG_DATA",
        "MS_TPC_SET_CMD",
};

/**
 * memstick_debug_get_tpc_name - debug helper that returns string for
 * a TPC number
 */
const char *memstick_debug_get_tpc_name(int tpc)
{
        return tpc_names[tpc-1];
}
EXPORT_SYMBOL(memstick_debug_get_tpc_name);


/* Read a register*/
static inline u32 r592_read_reg(struct r592_device *dev, int address)
{
        u32 value = readl(dev->mmio + address);
        dbg_reg("reg #%02d == 0x%08x", address, value);
        return value;
}

/* Write a register */
static inline void r592_write_reg(struct r592_device *dev,
                                                        int address, u32 value)
{
        dbg_reg("reg #%02d <- 0x%08x", address, value);
        writel(value, dev->mmio + address);
}

/* Reads a big endian DWORD register */
static inline u32 r592_read_reg_raw_be(struct r592_device *dev, int address)
{
        u32 value = __raw_readl(dev->mmio + address);
        dbg_reg("reg #%02d == 0x%08x", address, value);
        return be32_to_cpu(value);
}

/* Writes a big endian DWORD register */
static inline void r592_write_reg_raw_be(struct r592_device *dev,
                                                        int address, u32 value)
{
        dbg_reg("reg #%02d <- 0x%08x", address, value);
        __raw_writel(cpu_to_be32(value), dev->mmio + address);
}

/* Set specific bits in a register (little endian) */
static inline void r592_set_reg_mask(struct r592_device *dev,
                                                        int address, u32 mask)
{
        u32 reg = readl(dev->mmio + address);
        dbg_reg("reg #%02d |= 0x%08x (old =0x%08x)", address, mask, reg);
        writel(reg | mask , dev->mmio + address);
}

/* Clear specific bits in a register (little endian) */
static inline void r592_clear_reg_mask(struct r592_device *dev,
                                                int address, u32 mask)
{
        u32 reg = readl(dev->mmio + address);
        dbg_reg("reg #%02d &= 0x%08x (old = 0x%08x, mask = 0x%08x)",
                                                address, ~mask, reg, mask);
        writel(reg & ~mask, dev->mmio + address);
}


/* Wait for status bits while checking for errors */
static int r592_wait_status(struct r592_device *dev, u32 mask, u32 wanted_mask)
{
        unsigned long timeout = jiffies + msecs_to_jiffies(1000);
        u32 reg = r592_read_reg(dev, R592_STATUS);

        if ((reg & mask) == wanted_mask)
                return 0;

        while (time_before(jiffies, timeout)) {

                reg = r592_read_reg(dev, R592_STATUS);

                if ((reg & mask) == wanted_mask)
                        return 0;

                if (reg & (R592_STATUS_SEND_ERR | R592_STATUS_RECV_ERR))
                        return -EIO;

                cpu_relax();
        }
        return -ETIME;
}


/* Enable/disable device */
static int r592_enable_device(struct r592_device *dev, bool enable)
{
        dbg("%sabling the device", enable ? "en" : "dis");

        if (enable) {

                /* Power up the card */
                r592_write_reg(dev, R592_POWER, R592_POWER_0 | R592_POWER_1);

                /* Perform a reset */
                r592_set_reg_mask(dev, R592_IO, R592_IO_RESET);

                msleep(100);
        } else
                /* Power down the card */
                r592_write_reg(dev, R592_POWER, 0);

        return 0;
}

/* Set serial/parallel mode */
static int r592_set_mode(struct r592_device *dev, bool parallel_mode)
{
        if (!parallel_mode) {
                dbg("switching to serial mode");

                /* Set serial mode */
                r592_write_reg(dev, R592_IO_MODE, R592_IO_MODE_SERIAL);

                r592_clear_reg_mask(dev, R592_POWER, R592_POWER_20);

        } else {
                dbg("switching to parallel mode");

                /* This setting should be set _before_ switch TPC */
                r592_set_reg_mask(dev, R592_POWER, R592_POWER_20);

                r592_clear_reg_mask(dev, R592_IO,
                        R592_IO_SERIAL1 | R592_IO_SERIAL2);

                /* Set the parallel mode now */
                r592_write_reg(dev, R592_IO_MODE, R592_IO_MODE_PARALLEL);
        }

        dev->parallel_mode = parallel_mode;
        return 0;
}

/* Perform a controller reset without powering down the card */
static void r592_host_reset(struct r592_device *dev)
{
        r592_set_reg_mask(dev, R592_IO, R592_IO_RESET);
        msleep(100);
        r592_set_mode(dev, dev->parallel_mode);
}

/* Disable all hardware interrupts */
static void r592_clear_interrupts(struct r592_device *dev)
{
        /* Disable & ACK all interrupts */
        r592_clear_reg_mask(dev, R592_REG_MSC, IRQ_ALL_ACK_MASK);
        r592_clear_reg_mask(dev, R592_REG_MSC, IRQ_ALL_EN_MASK);
}

/* Tests if there is an CRC error */
static int r592_test_io_error(struct r592_device *dev)
{
        if (!(r592_read_reg(dev, R592_STATUS) &
                (R592_STATUS_SEND_ERR | R592_STATUS_RECV_ERR)))
                return 0;

        return -EIO;
}

/* Ensure that FIFO is ready for use */
static int r592_test_fifo_empty(struct r592_device *dev)
{
        if (r592_read_reg(dev, R592_REG_MSC) & R592_REG_MSC_FIFO_EMPTY)
                return 0;

        dbg("FIFO not ready, trying to reset the device");
        r592_host_reset(dev);

        if (r592_read_reg(dev, R592_REG_MSC) & R592_REG_MSC_FIFO_EMPTY)
                return 0;

        message("FIFO still not ready, giving up");
        return -EIO;
}

/* Activates the DMA transfer from to FIFO */
static void r592_start_dma(struct r592_device *dev, bool is_write)
{
        unsigned long flags;
        u32 reg;
        spin_lock_irqsave(&dev->irq_lock, flags);

        /* Ack interrupts (just in case) + enable them */
        r592_clear_reg_mask(dev, R592_REG_MSC, DMA_IRQ_ACK_MASK);
        r592_set_reg_mask(dev, R592_REG_MSC, DMA_IRQ_EN_MASK);

        /* Set DMA address */
        r592_write_reg(dev, R592_FIFO_DMA, sg_dma_address(&dev->req->sg));

        /* Enable the DMA */
        reg = r592_read_reg(dev, R592_FIFO_DMA_SETTINGS);
        reg |= R592_FIFO_DMA_SETTINGS_EN;

        if (!is_write)
                reg |= R592_FIFO_DMA_SETTINGS_DIR;
        else
                reg &= ~R592_FIFO_DMA_SETTINGS_DIR;
        r592_write_reg(dev, R592_FIFO_DMA_SETTINGS, reg);

        spin_unlock_irqrestore(&dev->irq_lock, flags);
}

/* Cleanups DMA related settings */
static void r592_stop_dma(struct r592_device *dev, int error)
{
        r592_clear_reg_mask(dev, R592_FIFO_DMA_SETTINGS,
                R592_FIFO_DMA_SETTINGS_EN);

        /* This is only a precation */
        r592_write_reg(dev, R592_FIFO_DMA,
                        dev->dummy_dma_page_physical_address);

        r592_clear_reg_mask(dev, R592_REG_MSC, DMA_IRQ_EN_MASK);
        r592_clear_reg_mask(dev, R592_REG_MSC, DMA_IRQ_ACK_MASK);
        dev->dma_error = error;
}

/* Test if hardware supports DMA */
static void r592_check_dma(struct r592_device *dev)
{
        dev->dma_capable = r592_enable_dma &&
                (r592_read_reg(dev, R592_FIFO_DMA_SETTINGS) &
                        R592_FIFO_DMA_SETTINGS_CAP);
}

/* Transfers fifo contents in/out using DMA */
static int r592_transfer_fifo_dma(struct r592_device *dev)
{
        int len, sg_count;
        bool is_write;

        if (!dev->dma_capable || !dev->req->long_data)
                return -EINVAL;

        len = dev->req->sg.length;
        is_write = dev->req->data_dir == WRITE;

        if (len != R592_LFIFO_SIZE)
                return -EINVAL;

        dbg_verbose("doing dma transfer");

        dev->dma_error = 0;
        INIT_COMPLETION(dev->dma_done);

        /* TODO: hidden assumption about nenth beeing always 1 */
        sg_count = dma_map_sg(&dev->pci_dev->dev, &dev->req->sg, 1, is_write ?
                PCI_DMA_TODEVICE : PCI_DMA_FROMDEVICE);

        if (sg_count != 1 ||
                        (sg_dma_len(&dev->req->sg) < dev->req->sg.length)) {
                message("problem in dma_map_sg");
                return -EIO;
        }

        r592_start_dma(dev, is_write);

        /* Wait for DMA completion */
        if (!wait_for_completion_timeout(
                        &dev->dma_done, msecs_to_jiffies(1000))) {
                message("DMA timeout");
                r592_stop_dma(dev, -ETIMEDOUT);
        }

        dma_unmap_sg(&dev->pci_dev->dev, &dev->req->sg, 1, is_write ?
                PCI_DMA_TODEVICE : PCI_DMA_FROMDEVICE);


        return dev->dma_error;
}

/*
 * Writes the FIFO in 4 byte chunks.
 * If length isn't 4 byte aligned, rest of the data if put to a fifo
 * to be written later
 * Use r592_flush_fifo_write to flush that fifo when writing for the
 * last time
 */
static void r592_write_fifo_pio(struct r592_device *dev,
                                        unsigned char *buffer, int len)
{
        /* flush spill from former write */
        if (!kfifo_is_empty(&dev->pio_fifo)) {

                u8 tmp[4] = {0};
                int copy_len = kfifo_in(&dev->pio_fifo, buffer, len);

                if (!kfifo_is_full(&dev->pio_fifo))
                        return;
                len -= copy_len;
                buffer += copy_len;

                copy_len = kfifo_out(&dev->pio_fifo, tmp, 4);
                WARN_ON(copy_len != 4);
                r592_write_reg_raw_be(dev, R592_FIFO_PIO, *(u32 *)tmp);
        }

        WARN_ON(!kfifo_is_empty(&dev->pio_fifo));

        /* write full dwords */
        while (len >= 4) {
                r592_write_reg_raw_be(dev, R592_FIFO_PIO, *(u32 *)buffer);
                buffer += 4;
                len -= 4;
        }

        /* put remaining bytes to the spill */
        if (len)
                kfifo_in(&dev->pio_fifo, buffer, len);
}

/* Flushes the temporary FIFO used to make aligned DWORD writes */
static void r592_flush_fifo_write(struct r592_device *dev)
{
        u8 buffer[4] = { 0 };
        int len;

        if (kfifo_is_empty(&dev->pio_fifo))
                return;

        len = kfifo_out(&dev->pio_fifo, buffer, 4);
        r592_write_reg_raw_be(dev, R592_FIFO_PIO, *(u32 *)buffer);
}

/*
 * Read a fifo in 4 bytes chunks.
 * If input doesn't fit the buffer, it places bytes of last dword in spill
 * buffer, so that they don't get lost on last read, just throw these away.
 */
static void r592_read_fifo_pio(struct r592_device *dev,
                                                unsigned char *buffer, int len)
{
        u8 tmp[4];

        /* Read from last spill */
        if (!kfifo_is_empty(&dev->pio_fifo)) {
                int bytes_copied =
                        kfifo_out(&dev->pio_fifo, buffer, min(4, len));
                buffer += bytes_copied;
                len -= bytes_copied;

                if (!kfifo_is_empty(&dev->pio_fifo))
                        return;
        }

        /* Reads dwords from FIFO */
        while (len >= 4) {
                *(u32 *)buffer = r592_read_reg_raw_be(dev, R592_FIFO_PIO);
                buffer += 4;
                len -= 4;
        }

        if (len) {
                *(u32 *)tmp = r592_read_reg_raw_be(dev, R592_FIFO_PIO);
                kfifo_in(&dev->pio_fifo, tmp, 4);
                len -= kfifo_out(&dev->pio_fifo, buffer, len);
        }

        WARN_ON(len);
        return;
}

/* Transfers actual data using PIO. */
static int r592_transfer_fifo_pio(struct r592_device *dev)
{
        unsigned long flags;

        bool is_write = dev->req->tpc >= MS_TPC_SET_RW_REG_ADRS;
        struct sg_mapping_iter miter;

        kfifo_reset(&dev->pio_fifo);

        if (!dev->req->long_data) {
                if (is_write) {
                        r592_write_fifo_pio(dev, dev->req->data,
                                                        dev->req->data_len);
                        r592_flush_fifo_write(dev);
                } else
                        r592_read_fifo_pio(dev, dev->req->data,
                                                        dev->req->data_len);
                return 0;
        }

        local_irq_save(flags);
        sg_miter_start(&miter, &dev->req->sg, 1, SG_MITER_ATOMIC |
                (is_write ? SG_MITER_FROM_SG : SG_MITER_TO_SG));

        /* Do the transfer fifo<->memory*/
        while (sg_miter_next(&miter))
                if (is_write)
                        r592_write_fifo_pio(dev, miter.addr, miter.length);
                else
                        r592_read_fifo_pio(dev, miter.addr, miter.length);


        /* Write last few non aligned bytes*/
        if (is_write)
                r592_flush_fifo_write(dev);

        sg_miter_stop(&miter);
        local_irq_restore(flags);
        return 0;
}

/* Executes one TPC (data is read/written from small or large fifo) */
static void r592_execute_tpc(struct r592_device *dev)
{
        bool is_write;
        int len, error;
        u32 status, reg;

        if (!dev->req) {
                message("BUG: tpc execution without request!");
                return;
        }

        is_write = dev->req->tpc >= MS_TPC_SET_RW_REG_ADRS;
        len = dev->req->long_data ?
                dev->req->sg.length : dev->req->data_len;

        /* Ensure that FIFO can hold the input data */
        if (len > R592_LFIFO_SIZE) {
                message("IO: hardware doesn't support TPCs longer that 512");
                error = -ENOSYS;
                goto out;
        }

        if (!(r592_read_reg(dev, R592_REG_MSC) & R592_REG_MSC_PRSNT)) {
                dbg("IO: refusing to send TPC because card is absent");
                error = -ENODEV;
                goto out;
        }

        dbg("IO: executing %s LEN=%d",
                        memstick_debug_get_tpc_name(dev->req->tpc), len);

        /* Set IO direction */
        if (is_write)
                r592_set_reg_mask(dev, R592_IO, R592_IO_DIRECTION);
        else
                r592_clear_reg_mask(dev, R592_IO, R592_IO_DIRECTION);


        error = r592_test_fifo_empty(dev);
        if (error)
                goto out;

        /* Transfer write data */
        if (is_write) {
                error = r592_transfer_fifo_dma(dev);
                if (error == -EINVAL)
                        error = r592_transfer_fifo_pio(dev);
        }

        if (error)
                goto out;

        /* Trigger the TPC */
        reg = (len << R592_TPC_EXEC_LEN_SHIFT) |
                (dev->req->tpc << R592_TPC_EXEC_TPC_SHIFT) |
                        R592_TPC_EXEC_BIG_FIFO;

        r592_write_reg(dev, R592_TPC_EXEC, reg);

        /* Wait for TPC completion */
        status = R592_STATUS_RDY;
        if (dev->req->need_card_int)
                status |= R592_STATUS_CED;

        error = r592_wait_status(dev, status, status);
        if (error) {
                message("card didn't respond");
                goto out;
        }

        /* Test IO errors */
        error = r592_test_io_error(dev);
        if (error) {
                dbg("IO error");
                goto out;
        }

        /* Read data from FIFO */
        if (!is_write) {
                error = r592_transfer_fifo_dma(dev);
                if (error == -EINVAL)
                        error = r592_transfer_fifo_pio(dev);
        }

        /* read INT reg. This can be shortened with shifts, but that way
                its more readable */
        if (dev->parallel_mode && dev->req->need_card_int) {

                dev->req->int_reg = 0;
                status = r592_read_reg(dev, R592_STATUS);

                if (status & R592_STATUS_P_CMDNACK)
                        dev->req->int_reg |= MEMSTICK_INT_CMDNAK;
                if (status & R592_STATUS_P_BREQ)
                        dev->req->int_reg |= MEMSTICK_INT_BREQ;
                if (status & R592_STATUS_P_INTERR)
                        dev->req->int_reg |= MEMSTICK_INT_ERR;
                if (status & R592_STATUS_P_CED)
                        dev->req->int_reg |= MEMSTICK_INT_CED;
        }

        if (error)
                dbg("FIFO read error");
out:
        dev->req->error = error;
        r592_clear_reg_mask(dev, R592_REG_MSC, R592_REG_MSC_LED);
        return;
}

/* Main request processing thread */
static int r592_process_thread(void *data)
{
        int error;
        struct r592_device *dev = (struct r592_device *)data;
        unsigned long flags;

        while (!kthread_should_stop()) {
                spin_lock_irqsave(&dev->io_thread_lock, flags);
                set_current_state(TASK_INTERRUPTIBLE);
                error = memstick_next_req(dev->host, &dev->req);
                spin_unlock_irqrestore(&dev->io_thread_lock, flags);

                if (error) {
                        if (error == -ENXIO || error == -EAGAIN) {
                                dbg_verbose("IO: done IO, sleeping");
                        } else {
                                dbg("IO: unknown error from "
                                        "memstick_next_req %d", error);
                        }

                        if (kthread_should_stop())
                                set_current_state(TASK_RUNNING);

                        schedule();
                } else {
                        set_current_state(TASK_RUNNING);
                        r592_execute_tpc(dev);
                }
        }
        return 0;
}

/* Reprogram chip to detect change in card state */
/* eg, if card is detected, arm it to detect removal, and vice versa */
static void r592_update_card_detect(struct r592_device *dev)
{
        u32 reg = r592_read_reg(dev, R592_REG_MSC);
        bool card_detected = reg & R592_REG_MSC_PRSNT;

        dbg("update card detect. card state: %s", card_detected ?
                "present" : "absent");

        reg &= ~((R592_REG_MSC_IRQ_REMOVE | R592_REG_MSC_IRQ_INSERT) << 16);

        if (card_detected)
                reg |= (R592_REG_MSC_IRQ_REMOVE << 16);
        else
                reg |= (R592_REG_MSC_IRQ_INSERT << 16);

        r592_write_reg(dev, R592_REG_MSC, reg);
}

/* Timer routine that fires 1 second after last card detection event, */
static void r592_detect_timer(long unsigned int data)
{
        struct r592_device *dev = (struct r592_device *)data;
        r592_update_card_detect(dev);
        memstick_detect_change(dev->host);
}

/* Interrupt handler */
static irqreturn_t r592_irq(int irq, void *data)
{
        struct r592_device *dev = (struct r592_device *)data;
        irqreturn_t ret = IRQ_NONE;
        u32 reg;
        u16 irq_enable, irq_status;
        unsigned long flags;
        int error;

        spin_lock_irqsave(&dev->irq_lock, flags);

        reg = r592_read_reg(dev, R592_REG_MSC);
        irq_enable = reg >> 16;
        irq_status = reg & 0xFFFF;

        /* Ack the interrupts */
        reg &= ~irq_status;
        r592_write_reg(dev, R592_REG_MSC, reg);

        /* Get the IRQ status minus bits that aren't enabled */
        irq_status &= (irq_enable);

        /* Due to limitation of memstick core, we don't look at bits that
                indicate that card was removed/inserted and/or present */
        if (irq_status & (R592_REG_MSC_IRQ_INSERT | R592_REG_MSC_IRQ_REMOVE)) {

                bool card_was_added = irq_status & R592_REG_MSC_IRQ_INSERT;
                ret = IRQ_HANDLED;

                message("IRQ: card %s", card_was_added ? "added" : "removed");

                mod_timer(&dev->detect_timer,
                        jiffies + msecs_to_jiffies(card_was_added ? 500 : 50));
        }

        if (irq_status &
                (R592_REG_MSC_FIFO_DMA_DONE | R592_REG_MSC_FIFO_DMA_ERR)) {
                ret = IRQ_HANDLED;

                if (irq_status & R592_REG_MSC_FIFO_DMA_ERR) {
                        message("IRQ: DMA error");
                        error = -EIO;
                } else {
                        dbg_verbose("IRQ: dma done");
                        error = 0;
                }

                r592_stop_dma(dev, error);
                complete(&dev->dma_done);
        }

        spin_unlock_irqrestore(&dev->irq_lock, flags);
        return ret;
}

/* External inteface: set settings */
static int r592_set_param(struct memstick_host *host,
                        enum memstick_param param, int value)
{
        struct r592_device *dev = memstick_priv(host);

        switch (param) {
        case MEMSTICK_POWER:
                switch (value) {
                case MEMSTICK_POWER_ON:
                        return r592_enable_device(dev, true);
                case MEMSTICK_POWER_OFF:
                        return r592_enable_device(dev, false);
                default:
                        return -EINVAL;
                }
        case MEMSTICK_INTERFACE:
                switch (value) {
                case MEMSTICK_SERIAL:
                        return r592_set_mode(dev, 0);
                case MEMSTICK_PAR4:
                        return r592_set_mode(dev, 1);
                default:
                        return -EINVAL;
                }
        default:
                return -EINVAL;
        }
}

/* External interface: submit requests */
static void r592_submit_req(struct memstick_host *host)
{
        struct r592_device *dev = memstick_priv(host);
        unsigned long flags;

        if (dev->req)
                return;

        spin_lock_irqsave(&dev->io_thread_lock, flags);
        if (wake_up_process(dev->io_thread))
                dbg_verbose("IO thread woken to process requests");
        spin_unlock_irqrestore(&dev->io_thread_lock, flags);
}

static const struct pci_device_id r592_pci_id_tbl[] = {

        { PCI_VDEVICE(RICOH, 0x0592), },
        { },
};

/* Main entry */
static int r592_probe(struct pci_dev *pdev, const struct pci_device_id *id)
{
        int error = -ENOMEM;
        struct memstick_host *host;
        struct r592_device *dev;

        /* Allocate memory */
        host = memstick_alloc_host(sizeof(struct r592_device), &pdev->dev);
        if (!host)
                goto error1;

        dev = memstick_priv(host);
        dev->host = host;
        dev->pci_dev = pdev;
        pci_set_drvdata(pdev, dev);

        /* pci initialization */
        error = pci_enable_device(pdev);
        if (error)
                goto error2;

        pci_set_master(pdev);
        error = pci_set_dma_mask(pdev, DMA_BIT_MASK(32));
        if (error)
                goto error3;

        error = pci_request_regions(pdev, DRV_NAME);
        if (error)
                goto error3;

        dev->mmio = pci_ioremap_bar(pdev, 0);
        if (!dev->mmio)
                goto error4;

        dev->irq = pdev->irq;
        spin_lock_init(&dev->irq_lock);
        spin_lock_init(&dev->io_thread_lock);
        init_completion(&dev->dma_done);
        INIT_KFIFO(dev->pio_fifo);
        setup_timer(&dev->detect_timer,
                r592_detect_timer, (long unsigned int)dev);

        /* Host initialization */
        host->caps = MEMSTICK_CAP_PAR4;
        host->request = r592_submit_req;
        host->set_param = r592_set_param;
        r592_check_dma(dev);

        dev->io_thread = kthread_run(r592_process_thread, dev, "r592_io");
        if (IS_ERR(dev->io_thread)) {
                error = PTR_ERR(dev->io_thread);
                goto error5;
        }

        /* This is just a precation, so don't fail */
        dev->dummy_dma_page = pci_alloc_consistent(pdev, PAGE_SIZE,
                &dev->dummy_dma_page_physical_address);
        r592_stop_dma(dev , 0);

        if (request_irq(dev->irq, &r592_irq, IRQF_SHARED,
                          DRV_NAME, dev))
                goto error6;

        r592_update_card_detect(dev);
        if (memstick_add_host(host))
                goto error7;

        message("driver successfully loaded");
        return 0;
error7:
        free_irq(dev->irq, dev);
error6:
        if (dev->dummy_dma_page)
                pci_free_consistent(pdev, PAGE_SIZE, dev->dummy_dma_page,
                        dev->dummy_dma_page_physical_address);

        kthread_stop(dev->io_thread);
error5:
        iounmap(dev->mmio);
error4:
        pci_release_regions(pdev);
error3:
        pci_disable_device(pdev);
error2:
        memstick_free_host(host);
error1:
        return error;
}

static void r592_remove(struct pci_dev *pdev)
{
        int error = 0;
        struct r592_device *dev = pci_get_drvdata(pdev);

        /* Stop the processing thread.
        That ensures that we won't take any more requests */
        kthread_stop(dev->io_thread);

        r592_enable_device(dev, false);

        while (!error && dev->req) {
                dev->req->error = -ETIME;
                error = memstick_next_req(dev->host, &dev->req);
        }
        memstick_remove_host(dev->host);

        free_irq(dev->irq, dev);
        iounmap(dev->mmio);
        pci_release_regions(pdev);
        pci_disable_device(pdev);
        memstick_free_host(dev->host);

        if (dev->dummy_dma_page)
                pci_free_consistent(pdev, PAGE_SIZE, dev->dummy_dma_page,
                        dev->dummy_dma_page_physical_address);
}

#ifdef CONFIG_PM_SLEEP
static int r592_suspend(struct device *core_dev)
{
        struct pci_dev *pdev = to_pci_dev(core_dev);
        struct r592_device *dev = pci_get_drvdata(pdev);

        r592_clear_interrupts(dev);
        memstick_suspend_host(dev->host);
        del_timer_sync(&dev->detect_timer);
        return 0;
}

static int r592_resume(struct device *core_dev)
{
        struct pci_dev *pdev = to_pci_dev(core_dev);
        struct r592_device *dev = pci_get_drvdata(pdev);

        r592_clear_interrupts(dev);
        r592_enable_device(dev, false);
        memstick_resume_host(dev->host);
        r592_update_card_detect(dev);
        return 0;
}
#endif

static SIMPLE_DEV_PM_OPS(r592_pm_ops, r592_suspend, r592_resume);

MODULE_DEVICE_TABLE(pci, r592_pci_id_tbl);

static struct pci_driver r852_pci_driver = {
        .name           = DRV_NAME,
        .id_table       = r592_pci_id_tbl,
        .probe          = r592_probe,
        .remove         = r592_remove,
        .driver.pm      = &r592_pm_ops,
};

module_pci_driver(r852_pci_driver);

module_param_named(enable_dma, r592_enable_dma, bool, S_IRUGO);
MODULE_PARM_DESC(enable_dma, "Enable usage of the DMA (default)");
module_param(debug, int, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(debug, "Debug level (0-3)");

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Maxim Levitsky <maximlevitsky@gmail.com>");
MODULE_DESCRIPTION("Ricoh R5C592 Memstick/Memstick PRO card reader driver");