/*
   * Copyright © 2009 - Maxim Levitsky
   * driver for Ricoh xD 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/jiffies.h>
  #include <linux/workqueue.h>
  #include <linux/interrupt.h>
  #include <linux/pci.h>
  #include <linux/pci_ids.h>
  #include <linux/delay.h>
  #include <linux/slab.h>
  #include <asm/byteorder.h>
  #include <linux/sched.h>
  #include "sm_common.h"
  #include "r852.h"
  
  
  static bool r852_enable_dma = 1;
  module_param(r852_enable_dma, bool, S_IRUGO);
  MODULE_PARM_DESC(r852_enable_dma, "Enable usage of the DMA (default)");
  
  static int debug;
  module_param(debug, int, S_IRUGO | S_IWUSR);
  MODULE_PARM_DESC(debug, "Debug level (0-2)");
  
  /* read register */
  static inline uint8_t r852_read_reg(struct r852_device *dev, int address)
  {
  	uint8_t reg = readb(dev->mmio + address);
  	return reg;
  }
  
  /* write register */
  static inline void r852_write_reg(struct r852_device *dev,
  						int address, uint8_t value)
  {
  	writeb(value, dev->mmio + address);
  	mmiowb();
  }
  
  
  /* read dword sized register */
  static inline uint32_t r852_read_reg_dword(struct r852_device *dev, int address)
  {
  	uint32_t reg = le32_to_cpu(readl(dev->mmio + address));
  	return reg;
  }
  
  /* write dword sized register */
  static inline void r852_write_reg_dword(struct r852_device *dev,
  							int address, uint32_t value)
  {
  	writel(cpu_to_le32(value), dev->mmio + address);
  	mmiowb();
  }
  
  /* returns pointer to our private structure */
  static inline struct r852_device *r852_get_dev(struct mtd_info *mtd)
  {
  	struct nand_chip *chip = mtd->priv;
  	return chip->priv;
  }
  
  
  /* check if controller supports dma */
  static void r852_dma_test(struct r852_device *dev)
  {
  	dev->dma_usable = (r852_read_reg(dev, R852_DMA_CAP) &
  		(R852_DMA1 | R852_DMA2)) == (R852_DMA1 | R852_DMA2);
  
  	if (!dev->dma_usable)
  		message("Non dma capable device detected, dma disabled");
  
  	if (!r852_enable_dma) {
  		message("disabling dma on user request");
  		dev->dma_usable = 0;
  	}
  }
  
  /*
   * Enable dma. Enables ether first or second stage of the DMA,
   * Expects dev->dma_dir and dev->dma_state be set
   */
  static void r852_dma_enable(struct r852_device *dev)
  {
  	uint8_t dma_reg, dma_irq_reg;
  
  	/* Set up dma settings */
  	dma_reg = r852_read_reg_dword(dev, R852_DMA_SETTINGS);
  	dma_reg &= ~(R852_DMA_READ | R852_DMA_INTERNAL | R852_DMA_MEMORY);
  
  	if (dev->dma_dir)
  		dma_reg |= R852_DMA_READ;
  
  	if (dev->dma_state == DMA_INTERNAL) {
  		dma_reg |= R852_DMA_INTERNAL;
  		/* Precaution to make sure HW doesn't write */
  			/* to random kernel memory */
  		r852_write_reg_dword(dev, R852_DMA_ADDR,
  			cpu_to_le32(dev->phys_bounce_buffer));
  	} else {
  		dma_reg |= R852_DMA_MEMORY;
  		r852_write_reg_dword(dev, R852_DMA_ADDR,
  			cpu_to_le32(dev->phys_dma_addr));
  	}
  
  	/* Precaution: make sure write reached the device */
  	r852_read_reg_dword(dev, R852_DMA_ADDR);
  
  	r852_write_reg_dword(dev, R852_DMA_SETTINGS, dma_reg);
  
  	/* Set dma irq */
  	dma_irq_reg = r852_read_reg_dword(dev, R852_DMA_IRQ_ENABLE);
  	r852_write_reg_dword(dev, R852_DMA_IRQ_ENABLE,
  		dma_irq_reg |
  		R852_DMA_IRQ_INTERNAL |
  		R852_DMA_IRQ_ERROR |
  		R852_DMA_IRQ_MEMORY);
  }
  
  /*
   * Disable dma, called from the interrupt handler, which specifies
   * success of the operation via 'error' argument
   */
  static void r852_dma_done(struct r852_device *dev, int error)
  {
  	WARN_ON(dev->dma_stage == 0);
  
  	r852_write_reg_dword(dev, R852_DMA_IRQ_STA,
  			r852_read_reg_dword(dev, R852_DMA_IRQ_STA));
  
  	r852_write_reg_dword(dev, R852_DMA_SETTINGS, 0);
  	r852_write_reg_dword(dev, R852_DMA_IRQ_ENABLE, 0);
  
  	/* Precaution to make sure HW doesn't write to random kernel memory */
  	r852_write_reg_dword(dev, R852_DMA_ADDR,
  		cpu_to_le32(dev->phys_bounce_buffer));
  	r852_read_reg_dword(dev, R852_DMA_ADDR);
  
  	dev->dma_error = error;
  	dev->dma_stage = 0;
  
  	if (dev->phys_dma_addr && dev->phys_dma_addr != dev->phys_bounce_buffer)
  		pci_unmap_single(dev->pci_dev, dev->phys_dma_addr, R852_DMA_LEN,
  			dev->dma_dir ? PCI_DMA_FROMDEVICE : PCI_DMA_TODEVICE);
  }
  
  /*
   * Wait, till dma is done, which includes both phases of it
   */
  static int r852_dma_wait(struct r852_device *dev)
  {
  	long timeout = wait_for_completion_timeout(&dev->dma_done,
  				msecs_to_jiffies(1000));
  	if (!timeout) {
  		dbg("timeout waiting for DMA interrupt");
  		return -ETIMEDOUT;
  	}
  
  	return 0;
  }
  
  /*
   * Read/Write one page using dma. Only pages can be read (512 bytes)
  */
  static void r852_do_dma(struct r852_device *dev, uint8_t *buf, int do_read)
  {
  	int bounce = 0;
  	unsigned long flags;
  	int error;
  
  	dev->dma_error = 0;
  
  	/* Set dma direction */
  	dev->dma_dir = do_read;
  	dev->dma_stage = 1;
  	reinit_completion(&dev->dma_done);
  
  	dbg_verbose("doing dma %s ", do_read ? "read" : "write");
  
  	/* Set initial dma state: for reading first fill on board buffer,
  	  from device, for writes first fill the buffer  from memory*/
  	dev->dma_state = do_read ? DMA_INTERNAL : DMA_MEMORY;
  
  	/* if incoming buffer is not page aligned, we should do bounce */
  	if ((unsigned long)buf & (R852_DMA_LEN-1))
  		bounce = 1;
  
  	if (!bounce) {
  		dev->phys_dma_addr = pci_map_single(dev->pci_dev, (void *)buf,
  			R852_DMA_LEN,
  			(do_read ? PCI_DMA_FROMDEVICE : PCI_DMA_TODEVICE));
  
  		if (pci_dma_mapping_error(dev->pci_dev, dev->phys_dma_addr))
  			bounce = 1;
  	}
  
  	if (bounce) {
  		dbg_verbose("dma: using bounce buffer");
  		dev->phys_dma_addr = dev->phys_bounce_buffer;
  		if (!do_read)
  			memcpy(dev->bounce_buffer, buf, R852_DMA_LEN);
  	}
  
  	/* Enable DMA */
  	spin_lock_irqsave(&dev->irqlock, flags);
  	r852_dma_enable(dev);
  	spin_unlock_irqrestore(&dev->irqlock, flags);
  
  	/* Wait till complete */
  	error = r852_dma_wait(dev);
  
  	if (error) {
  		r852_dma_done(dev, error);
  		return;
  	}
  
  	if (do_read && bounce)
  		memcpy((void *)buf, dev->bounce_buffer, R852_DMA_LEN);
  }
  
  /*
   * Program data lines of the nand chip to send data to it
   */
  static void r852_write_buf(struct mtd_info *mtd, const uint8_t *buf, int len)
  {
  	struct r852_device *dev = r852_get_dev(mtd);
  	uint32_t reg;
  
  	/* Don't allow any access to hardware if we suspect card removal */
  	if (dev->card_unstable)
  		return;
  
  	/* Special case for whole sector read */
  	if (len == R852_DMA_LEN && dev->dma_usable) {
  		r852_do_dma(dev, (uint8_t *)buf, 0);
  		return;
  	}
  
  	/* write DWORD chinks - faster */
  	while (len >= 4) {
  		reg = buf[0] | buf[1] << 8 | buf[2] << 16 | buf[3] << 24;
  		r852_write_reg_dword(dev, R852_DATALINE, reg);
  		buf += 4;
  		len -= 4;
  
  	}
  
  	/* write rest */
  	while (len > 0) {
  		r852_write_reg(dev, R852_DATALINE, *buf++);
  		len--;
  	}
  }
  
  /*
   * Read data lines of the nand chip to retrieve data
   */
  static void r852_read_buf(struct mtd_info *mtd, uint8_t *buf, int len)
  {
  	struct r852_device *dev = r852_get_dev(mtd);
  	uint32_t reg;
  
  	if (dev->card_unstable) {
  		/* since we can't signal error here, at least, return
  			predictable buffer */
  		memset(buf, 0, len);
  		return;
  	}
  
  	/* special case for whole sector read */
  	if (len == R852_DMA_LEN && dev->dma_usable) {
  		r852_do_dma(dev, buf, 1);
  		return;
  	}
  
  	/* read in dword sized chunks */
  	while (len >= 4) {
  
  		reg = r852_read_reg_dword(dev, R852_DATALINE);
  		*buf++ = reg & 0xFF;
  		*buf++ = (reg >> 8) & 0xFF;
  		*buf++ = (reg >> 16) & 0xFF;
  		*buf++ = (reg >> 24) & 0xFF;
  		len -= 4;
  	}
  
  	/* read the reset by bytes */
  	while (len--)
  		*buf++ = r852_read_reg(dev, R852_DATALINE);
  }
  
  /*
   * Read one byte from nand chip
   */
  static uint8_t r852_read_byte(struct mtd_info *mtd)
  {
  	struct r852_device *dev = r852_get_dev(mtd);
  
  	/* Same problem as in r852_read_buf.... */
  	if (dev->card_unstable)
  		return 0;
  
  	return r852_read_reg(dev, R852_DATALINE);
  }
  
  /*
   * Control several chip lines & send commands
   */
  static void r852_cmdctl(struct mtd_info *mtd, int dat, unsigned int ctrl)
  {
  	struct r852_device *dev = r852_get_dev(mtd);
  
  	if (dev->card_unstable)
  		return;
  
  	if (ctrl & NAND_CTRL_CHANGE) {
  
  		dev->ctlreg &= ~(R852_CTL_DATA | R852_CTL_COMMAND |
  				 R852_CTL_ON | R852_CTL_CARDENABLE);
  
  		if (ctrl & NAND_ALE)
  			dev->ctlreg |= R852_CTL_DATA;
  
  		if (ctrl & NAND_CLE)
  			dev->ctlreg |= R852_CTL_COMMAND;
  
  		if (ctrl & NAND_NCE)
  			dev->ctlreg |= (R852_CTL_CARDENABLE | R852_CTL_ON);
  		else
  			dev->ctlreg &= ~R852_CTL_WRITE;
  
  		/* when write is stareted, enable write access */
  		if (dat == NAND_CMD_ERASE1)
  			dev->ctlreg |= R852_CTL_WRITE;
  
  		r852_write_reg(dev, R852_CTL, dev->ctlreg);
  	}
  
  	 /* HACK: NAND_CMD_SEQIN is called without NAND_CTRL_CHANGE, but we need
  		to set write mode */
  	if (dat == NAND_CMD_SEQIN && (dev->ctlreg & R852_CTL_COMMAND)) {
  		dev->ctlreg |= R852_CTL_WRITE;
  		r852_write_reg(dev, R852_CTL, dev->ctlreg);
  	}
  
  	if (dat != NAND_CMD_NONE)
  		r852_write_reg(dev, R852_DATALINE, dat);
  }
  
  /*
   * Wait till card is ready.
   * based on nand_wait, but returns errors on DMA error
   */
  static int r852_wait(struct mtd_info *mtd, struct nand_chip *chip)
  {
  	struct r852_device *dev = chip->priv;
  
  	unsigned long timeout;
  	int status;
  
  	timeout = jiffies + (chip->state == FL_ERASING ?
  		msecs_to_jiffies(400) : msecs_to_jiffies(20));
  
  	while (time_before(jiffies, timeout))
  		if (chip->dev_ready(mtd))
  			break;
  
  	chip->cmdfunc(mtd, NAND_CMD_STATUS, -1, -1);
  	status = (int)chip->read_byte(mtd);
  
  	/* Unfortunelly, no way to send detailed error status... */
  	if (dev->dma_error) {
  		status |= NAND_STATUS_FAIL;
  		dev->dma_error = 0;
  	}
  	return status;
  }
  
  /*
   * Check if card is ready
   */
  
  static int r852_ready(struct mtd_info *mtd)
  {
  	struct r852_device *dev = r852_get_dev(mtd);
  	return !(r852_read_reg(dev, R852_CARD_STA) & R852_CARD_STA_BUSY);
  }
  
  
  /*
   * Set ECC engine mode
  */
  
  static void r852_ecc_hwctl(struct mtd_info *mtd, int mode)
  {
  	struct r852_device *dev = r852_get_dev(mtd);
  
  	if (dev->card_unstable)
  		return;
  
  	switch (mode) {
  	case NAND_ECC_READ:
  	case NAND_ECC_WRITE:
  		/* enable ecc generation/check*/
  		dev->ctlreg |= R852_CTL_ECC_ENABLE;
  
  		/* flush ecc buffer */
  		r852_write_reg(dev, R852_CTL,
  			dev->ctlreg | R852_CTL_ECC_ACCESS);
  
  		r852_read_reg_dword(dev, R852_DATALINE);
  		r852_write_reg(dev, R852_CTL, dev->ctlreg);
  		return;
  
  	case NAND_ECC_READSYN:
  		/* disable ecc generation */
  		dev->ctlreg &= ~R852_CTL_ECC_ENABLE;
  		r852_write_reg(dev, R852_CTL, dev->ctlreg);
  	}
  }
  
  /*
   * Calculate ECC, only used for writes
   */
  
  static int r852_ecc_calculate(struct mtd_info *mtd, const uint8_t *dat,
  							uint8_t *ecc_code)
  {
  	struct r852_device *dev = r852_get_dev(mtd);
  	struct sm_oob *oob = (struct sm_oob *)ecc_code;
  	uint32_t ecc1, ecc2;
  
  	if (dev->card_unstable)
  		return 0;
  
  	dev->ctlreg &= ~R852_CTL_ECC_ENABLE;
  	r852_write_reg(dev, R852_CTL, dev->ctlreg | R852_CTL_ECC_ACCESS);
  
  	ecc1 = r852_read_reg_dword(dev, R852_DATALINE);
  	ecc2 = r852_read_reg_dword(dev, R852_DATALINE);
  
  	oob->ecc1[0] = (ecc1) & 0xFF;
  	oob->ecc1[1] = (ecc1 >> 8) & 0xFF;
  	oob->ecc1[2] = (ecc1 >> 16) & 0xFF;
  
  	oob->ecc2[0] = (ecc2) & 0xFF;
  	oob->ecc2[1] = (ecc2 >> 8) & 0xFF;
  	oob->ecc2[2] = (ecc2 >> 16) & 0xFF;
  
  	r852_write_reg(dev, R852_CTL, dev->ctlreg);
  	return 0;
  }
  
  /*
   * Correct the data using ECC, hw did almost everything for us
   */
  
  static int r852_ecc_correct(struct mtd_info *mtd, uint8_t *dat,
  				uint8_t *read_ecc, uint8_t *calc_ecc)
  {
  	uint32_t ecc_reg;
  	uint8_t ecc_status, err_byte;
  	int i, error = 0;
  
  	struct r852_device *dev = r852_get_dev(mtd);
  
  	if (dev->card_unstable)
  		return 0;
  
  	if (dev->dma_error) {
  		dev->dma_error = 0;
  		return -EIO;
  	}
  
  	r852_write_reg(dev, R852_CTL, dev->ctlreg | R852_CTL_ECC_ACCESS);
  	ecc_reg = r852_read_reg_dword(dev, R852_DATALINE);
  	r852_write_reg(dev, R852_CTL, dev->ctlreg);
  
  	for (i = 0 ; i <= 1 ; i++) {
  
  		ecc_status = (ecc_reg >> 8) & 0xFF;
  
  		/* ecc uncorrectable error */
  		if (ecc_status & R852_ECC_FAIL) {
  			dbg("ecc: unrecoverable error, in half %d", i);
  			error = -EBADMSG;
  			goto exit;
  		}
  
  		/* correctable error */
  		if (ecc_status & R852_ECC_CORRECTABLE) {
  
  			err_byte = ecc_reg & 0xFF;
  			dbg("ecc: recoverable error, "
  				"in half %d, byte %d, bit %d", i,
  				err_byte, ecc_status & R852_ECC_ERR_BIT_MSK);
  
  			dat[err_byte] ^=
  				1 << (ecc_status & R852_ECC_ERR_BIT_MSK);
  			error++;
  		}
  
  		dat += 256;
  		ecc_reg >>= 16;
  	}
  exit:
  	return error;
  }
  
  /*
   * This is copy of nand_read_oob_std
   * nand_read_oob_syndrome assumes we can send column address - we can't
   */
  static int r852_read_oob(struct mtd_info *mtd, struct nand_chip *chip,
  			     int page)
  {
  	chip->cmdfunc(mtd, NAND_CMD_READOOB, 0, page);
  	chip->read_buf(mtd, chip->oob_poi, mtd->oobsize);
  	return 0;
  }
  
  /*
   * Start the nand engine
   */
  
  static void r852_engine_enable(struct r852_device *dev)
  {
  	if (r852_read_reg_dword(dev, R852_HW) & R852_HW_UNKNOWN) {
  		r852_write_reg(dev, R852_CTL, R852_CTL_RESET | R852_CTL_ON);
  		r852_write_reg_dword(dev, R852_HW, R852_HW_ENABLED);
  	} else {
  		r852_write_reg_dword(dev, R852_HW, R852_HW_ENABLED);
  		r852_write_reg(dev, R852_CTL, R852_CTL_RESET | R852_CTL_ON);
  	}
  	msleep(300);
  	r852_write_reg(dev, R852_CTL, 0);
  }
  
  
  /*
   * Stop the nand engine
   */
  
  static void r852_engine_disable(struct r852_device *dev)
  {
  	r852_write_reg_dword(dev, R852_HW, 0);
  	r852_write_reg(dev, R852_CTL, R852_CTL_RESET);
  }
  
  /*
   * Test if card is present
   */
  
  static void r852_card_update_present(struct r852_device *dev)
  {
  	unsigned long flags;
  	uint8_t reg;
  
  	spin_lock_irqsave(&dev->irqlock, flags);
  	reg = r852_read_reg(dev, R852_CARD_STA);
  	dev->card_detected = !!(reg & R852_CARD_STA_PRESENT);
  	spin_unlock_irqrestore(&dev->irqlock, flags);
  }
  
  /*
   * Update card detection IRQ state according to current card state
   * which is read in r852_card_update_present
   */
  static void r852_update_card_detect(struct r852_device *dev)
  {
  	int card_detect_reg = r852_read_reg(dev, R852_CARD_IRQ_ENABLE);
  	dev->card_unstable = 0;
  
  	card_detect_reg &= ~(R852_CARD_IRQ_REMOVE | R852_CARD_IRQ_INSERT);
  	card_detect_reg |= R852_CARD_IRQ_GENABLE;
  
  	card_detect_reg |= dev->card_detected ?
  		R852_CARD_IRQ_REMOVE : R852_CARD_IRQ_INSERT;
  
  	r852_write_reg(dev, R852_CARD_IRQ_ENABLE, card_detect_reg);
  }
  
  static ssize_t r852_media_type_show(struct device *sys_dev,
  			struct device_attribute *attr, char *buf)
  {
  	struct mtd_info *mtd = container_of(sys_dev, struct mtd_info, dev);
  	struct r852_device *dev = r852_get_dev(mtd);
  	char *data = dev->sm ? "smartmedia" : "xd";
  
  	strcpy(buf, data);
  	return strlen(data);
  }
  
  static DEVICE_ATTR(media_type, S_IRUGO, r852_media_type_show, NULL);
  
  
  /* Detect properties of card in slot */
  static void r852_update_media_status(struct r852_device *dev)
  {
  	uint8_t reg;
  	unsigned long flags;
  	int readonly;
  
  	spin_lock_irqsave(&dev->irqlock, flags);
  	if (!dev->card_detected) {
  		message("card removed");
  		spin_unlock_irqrestore(&dev->irqlock, flags);
  		return ;
  	}
  
  	readonly  = r852_read_reg(dev, R852_CARD_STA) & R852_CARD_STA_RO;
  	reg = r852_read_reg(dev, R852_DMA_CAP);
  	dev->sm = (reg & (R852_DMA1 | R852_DMA2)) && (reg & R852_SMBIT);
  
  	message("detected %s %s card in slot",
  		dev->sm ? "SmartMedia" : "xD",
  		readonly ? "readonly" : "writeable");
  
  	dev->readonly = readonly;
  	spin_unlock_irqrestore(&dev->irqlock, flags);
  }
  
  /*
   * Register the nand device
   * Called when the card is detected
   */
  static int r852_register_nand_device(struct r852_device *dev)
  {
  	dev->mtd = kzalloc(sizeof(struct mtd_info), GFP_KERNEL);
  
  	if (!dev->mtd)
  		goto error1;
  
  	WARN_ON(dev->card_registred);
  
  	dev->mtd->priv = dev->chip;
  	dev->mtd->dev.parent = &dev->pci_dev->dev;
  
  	if (dev->readonly)
  		dev->chip->options |= NAND_ROM;
  
  	r852_engine_enable(dev);
  
  	if (sm_register_device(dev->mtd, dev->sm))
  		goto error2;
  
  	if (device_create_file(&dev->mtd->dev, &dev_attr_media_type)) {
  		message("can't create media type sysfs attribute");
  		goto error3;
  	}
  
  	dev->card_registred = 1;
  	return 0;
  error3:
  	nand_release(dev->mtd);
  error2:
  	kfree(dev->mtd);
  error1:
  	/* Force card redetect */
  	dev->card_detected = 0;
  	return -1;
  }
  
  /*
   * Unregister the card
   */
  
  static void r852_unregister_nand_device(struct r852_device *dev)
  {
  	if (!dev->card_registred)
  		return;
  
  	device_remove_file(&dev->mtd->dev, &dev_attr_media_type);
  	nand_release(dev->mtd);
  	r852_engine_disable(dev);
  	dev->card_registred = 0;
  	kfree(dev->mtd);
  	dev->mtd = NULL;
  }
  
  /* Card state updater */
  static void r852_card_detect_work(struct work_struct *work)
  {
  	struct r852_device *dev =
  		container_of(work, struct r852_device, card_detect_work.work);
  
  	r852_card_update_present(dev);
  	r852_update_card_detect(dev);
  	dev->card_unstable = 0;
  
  	/* False alarm */
  	if (dev->card_detected == dev->card_registred)
  		goto exit;
  
  	/* Read media properties */
  	r852_update_media_status(dev);
  
  	/* Register the card */
  	if (dev->card_detected)
  		r852_register_nand_device(dev);
  	else
  		r852_unregister_nand_device(dev);
  exit:
  	r852_update_card_detect(dev);
  }
  
  /* Ack + disable IRQ generation */
  static void r852_disable_irqs(struct r852_device *dev)
  {
  	uint8_t reg;
  	reg = r852_read_reg(dev, R852_CARD_IRQ_ENABLE);
  	r852_write_reg(dev, R852_CARD_IRQ_ENABLE, reg & ~R852_CARD_IRQ_MASK);
  
  	reg = r852_read_reg_dword(dev, R852_DMA_IRQ_ENABLE);
  	r852_write_reg_dword(dev, R852_DMA_IRQ_ENABLE,
  					reg & ~R852_DMA_IRQ_MASK);
  
  	r852_write_reg(dev, R852_CARD_IRQ_STA, R852_CARD_IRQ_MASK);
  	r852_write_reg_dword(dev, R852_DMA_IRQ_STA, R852_DMA_IRQ_MASK);
  }
  
  /* Interrupt handler */
  static irqreturn_t r852_irq(int irq, void *data)
  {
  	struct r852_device *dev = (struct r852_device *)data;
  
  	uint8_t card_status, dma_status;
  	unsigned long flags;
  	irqreturn_t ret = IRQ_NONE;
  
  	spin_lock_irqsave(&dev->irqlock, flags);
  
  	/* handle card detection interrupts first */
  	card_status = r852_read_reg(dev, R852_CARD_IRQ_STA);
  	r852_write_reg(dev, R852_CARD_IRQ_STA, card_status);
  
  	if (card_status & (R852_CARD_IRQ_INSERT|R852_CARD_IRQ_REMOVE)) {
  
  		ret = IRQ_HANDLED;
  		dev->card_detected = !!(card_status & R852_CARD_IRQ_INSERT);
  
  		/* we shouldn't receive any interrupts if we wait for card
  			to settle */
  		WARN_ON(dev->card_unstable);
  
  		/* disable irqs while card is unstable */
  		/* this will timeout DMA if active, but better that garbage */
  		r852_disable_irqs(dev);
  
  		if (dev->card_unstable)
  			goto out;
  
  		/* let, card state to settle a bit, and then do the work */
  		dev->card_unstable = 1;
  		queue_delayed_work(dev->card_workqueue,
  			&dev->card_detect_work, msecs_to_jiffies(100));
  		goto out;
  	}
  
  
  	/* Handle dma interrupts */
  	dma_status = r852_read_reg_dword(dev, R852_DMA_IRQ_STA);
  	r852_write_reg_dword(dev, R852_DMA_IRQ_STA, dma_status);
  
  	if (dma_status & R852_DMA_IRQ_MASK) {
  
  		ret = IRQ_HANDLED;
  
  		if (dma_status & R852_DMA_IRQ_ERROR) {
  			dbg("received dma error IRQ");
  			r852_dma_done(dev, -EIO);
  			complete(&dev->dma_done);
  			goto out;
  		}
  
  		/* received DMA interrupt out of nowhere? */
  		WARN_ON_ONCE(dev->dma_stage == 0);
  
  		if (dev->dma_stage == 0)
  			goto out;
  
  		/* done device access */
  		if (dev->dma_state == DMA_INTERNAL &&
  				(dma_status & R852_DMA_IRQ_INTERNAL)) {
  
  			dev->dma_state = DMA_MEMORY;
  			dev->dma_stage++;
  		}
  
  		/* done memory DMA */
  		if (dev->dma_state == DMA_MEMORY &&
  				(dma_status & R852_DMA_IRQ_MEMORY)) {
  			dev->dma_state = DMA_INTERNAL;
  			dev->dma_stage++;
  		}
  
  		/* Enable 2nd half of dma dance */
  		if (dev->dma_stage == 2)
  			r852_dma_enable(dev);
  
  		/* Operation done */
  		if (dev->dma_stage == 3) {
  			r852_dma_done(dev, 0);
  			complete(&dev->dma_done);
  		}
  		goto out;
  	}
  
  	/* Handle unknown interrupts */
  	if (dma_status)
  		dbg("bad dma IRQ status = %x", dma_status);
  
  	if (card_status & ~R852_CARD_STA_CD)
  		dbg("strange card status = %x", card_status);
  
  out:
  	spin_unlock_irqrestore(&dev->irqlock, flags);
  	return ret;
  }
  
  static int  r852_probe(struct pci_dev *pci_dev, const struct pci_device_id *id)
  {
  	int error;
  	struct nand_chip *chip;
  	struct r852_device *dev;
  
  	/* pci initialization */
  	error = pci_enable_device(pci_dev);
  
  	if (error)
  		goto error1;
  
  	pci_set_master(pci_dev);
  
  	error = pci_set_dma_mask(pci_dev, DMA_BIT_MASK(32));
  	if (error)
  		goto error2;
  
  	error = pci_request_regions(pci_dev, DRV_NAME);
  
  	if (error)
  		goto error3;
  
  	error = -ENOMEM;
  
  	/* init nand chip, but register it only on card insert */
  	chip = kzalloc(sizeof(struct nand_chip), GFP_KERNEL);
  
  	if (!chip)
  		goto error4;
  
  	/* commands */
  	chip->cmd_ctrl = r852_cmdctl;
  	chip->waitfunc = r852_wait;
  	chip->dev_ready = r852_ready;
  
  	/* I/O */
  	chip->read_byte = r852_read_byte;
  	chip->read_buf = r852_read_buf;
  	chip->write_buf = r852_write_buf;
  
  	/* ecc */
  	chip->ecc.mode = NAND_ECC_HW_SYNDROME;
  	chip->ecc.size = R852_DMA_LEN;
  	chip->ecc.bytes = SM_OOB_SIZE;
  	chip->ecc.strength = 2;
  	chip->ecc.hwctl = r852_ecc_hwctl;
  	chip->ecc.calculate = r852_ecc_calculate;
  	chip->ecc.correct = r852_ecc_correct;
  
  	/* TODO: hack */
  	chip->ecc.read_oob = r852_read_oob;
  
  	/* init our device structure */
  	dev = kzalloc(sizeof(struct r852_device), GFP_KERNEL);
  
  	if (!dev)
  		goto error5;
  
  	chip->priv = dev;
  	dev->chip = chip;
  	dev->pci_dev = pci_dev;
  	pci_set_drvdata(pci_dev, dev);
  
  	dev->bounce_buffer = pci_alloc_consistent(pci_dev, R852_DMA_LEN,
  		&dev->phys_bounce_buffer);
  
  	if (!dev->bounce_buffer)
  		goto error6;
  
  
  	error = -ENODEV;
  	dev->mmio = pci_ioremap_bar(pci_dev, 0);
  
  	if (!dev->mmio)
  		goto error7;
  
  	error = -ENOMEM;
  	dev->tmp_buffer = kzalloc(SM_SECTOR_SIZE, GFP_KERNEL);
  
  	if (!dev->tmp_buffer)
  		goto error8;
  
  	init_completion(&dev->dma_done);
  
  	dev->card_workqueue = create_freezable_workqueue(DRV_NAME);
  
  	if (!dev->card_workqueue)
  		goto error9;
  
  	INIT_DELAYED_WORK(&dev->card_detect_work, r852_card_detect_work);
  
  	/* shutdown everything - precation */
  	r852_engine_disable(dev);
  	r852_disable_irqs(dev);
  
  	r852_dma_test(dev);
  
  	dev->irq = pci_dev->irq;
  	spin_lock_init(&dev->irqlock);
  
  	dev->card_detected = 0;
  	r852_card_update_present(dev);
  
  	/*register irq handler*/
  	error = -ENODEV;
  	if (request_irq(pci_dev->irq, &r852_irq, IRQF_SHARED,
  			  DRV_NAME, dev))
  		goto error10;
  
  	/* kick initial present test */
  	queue_delayed_work(dev->card_workqueue,
  		&dev->card_detect_work, 0);
  
  
  	printk(KERN_NOTICE DRV_NAME ": driver loaded successfully
  ");
  	return 0;
  
  error10:
  	destroy_workqueue(dev->card_workqueue);
  error9:
  	kfree(dev->tmp_buffer);
  error8:
  	pci_iounmap(pci_dev, dev->mmio);
  error7:
  	pci_free_consistent(pci_dev, R852_DMA_LEN,
  		dev->bounce_buffer, dev->phys_bounce_buffer);
  error6:
  	kfree(dev);
  error5:
  	kfree(chip);
  error4:
  	pci_release_regions(pci_dev);
  error3:
  error2:
  	pci_disable_device(pci_dev);
  error1:
  	return error;
  }
  
  static void r852_remove(struct pci_dev *pci_dev)
  {
  	struct r852_device *dev = pci_get_drvdata(pci_dev);
  
  	/* Stop detect workqueue -
  		we are going to unregister the device anyway*/
  	cancel_delayed_work_sync(&dev->card_detect_work);
  	destroy_workqueue(dev->card_workqueue);
  
  	/* Unregister the device, this might make more IO */
  	r852_unregister_nand_device(dev);
  
  	/* Stop interrupts */
  	r852_disable_irqs(dev);
  	synchronize_irq(dev->irq);
  	free_irq(dev->irq, dev);
  
  	/* Cleanup */
  	kfree(dev->tmp_buffer);
  	pci_iounmap(pci_dev, dev->mmio);
  	pci_free_consistent(pci_dev, R852_DMA_LEN,
  		dev->bounce_buffer, dev->phys_bounce_buffer);
  
  	kfree(dev->chip);
  	kfree(dev);
  
  	/* Shutdown the PCI device */
  	pci_release_regions(pci_dev);
  	pci_disable_device(pci_dev);
  }
  
  static void r852_shutdown(struct pci_dev *pci_dev)
  {
  	struct r852_device *dev = pci_get_drvdata(pci_dev);
  
  	cancel_delayed_work_sync(&dev->card_detect_work);
  	r852_disable_irqs(dev);
  	synchronize_irq(dev->irq);
  	pci_disable_device(pci_dev);
  }
  
  #ifdef CONFIG_PM_SLEEP
  static int r852_suspend(struct device *device)
  {
  	struct r852_device *dev = pci_get_drvdata(to_pci_dev(device));
  
  	if (dev->ctlreg & R852_CTL_CARDENABLE)
  		return -EBUSY;
  
  	/* First make sure the detect work is gone */
  	cancel_delayed_work_sync(&dev->card_detect_work);
  
  	/* Turn off the interrupts and stop the device */
  	r852_disable_irqs(dev);
  	r852_engine_disable(dev);
  
  	/* If card was pulled off just during the suspend, which is very
  		unlikely, we will remove it on resume, it too late now
  		anyway... */
  	dev->card_unstable = 0;
  	return 0;
  }
  
  static int r852_resume(struct device *device)
  {
  	struct r852_device *dev = pci_get_drvdata(to_pci_dev(device));
  
  	r852_disable_irqs(dev);
  	r852_card_update_present(dev);
  	r852_engine_disable(dev);
  
  
  	/* If card status changed, just do the work */
  	if (dev->card_detected != dev->card_registred) {
  		dbg("card was %s during low power state",
  			dev->card_detected ? "added" : "removed");
  
  		queue_delayed_work(dev->card_workqueue,
  		&dev->card_detect_work, msecs_to_jiffies(1000));
  		return 0;
  	}
  
  	/* Otherwise, initialize the card */
  	if (dev->card_registred) {
  		r852_engine_enable(dev);
  		dev->chip->select_chip(dev->mtd, 0);
  		dev->chip->cmdfunc(dev->mtd, NAND_CMD_RESET, -1, -1);
  		dev->chip->select_chip(dev->mtd, -1);
  	}
  
  	/* Program card detection IRQ */
  	r852_update_card_detect(dev);
  	return 0;
  }
  #endif
  
  static const struct pci_device_id r852_pci_id_tbl[] = {
  
  	{ PCI_VDEVICE(RICOH, 0x0852), },
  	{ },
  };
  
  MODULE_DEVICE_TABLE(pci, r852_pci_id_tbl);
  
  static SIMPLE_DEV_PM_OPS(r852_pm_ops, r852_suspend, r852_resume);
  
  static struct pci_driver r852_pci_driver = {
  	.name		= DRV_NAME,
  	.id_table	= r852_pci_id_tbl,
  	.probe		= r852_probe,
  	.remove		= r852_remove,
  	.shutdown	= r852_shutdown,
  	.driver.pm	= &r852_pm_ops,
  };
  
  module_pci_driver(r852_pci_driver);
  
  MODULE_LICENSE("GPL");
  MODULE_AUTHOR("Maxim Levitsky <maximlevitsky@gmail.com>");
  MODULE_DESCRIPTION("Ricoh 85xx xD/smartmedia card reader driver");