/*
   * Xilinx SystemACE device driver
   *
   * Copyright 2007 Secret Lab Technologies Ltd.
   *
   * 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.
   */
  
  /*
   * The SystemACE chip is designed to configure FPGAs by loading an FPGA
   * bitstream from a file on a CF card and squirting it into FPGAs connected
   * to the SystemACE JTAG chain.  It also has the advantage of providing an
   * MPU interface which can be used to control the FPGA configuration process
   * and to use the attached CF card for general purpose storage.
   *
   * This driver is a block device driver for the SystemACE.
   *
   * Initialization:
   *    The driver registers itself as a platform_device driver at module
   *    load time.  The platform bus will take care of calling the
   *    ace_probe() method for all SystemACE instances in the system.  Any
   *    number of SystemACE instances are supported.  ace_probe() calls
   *    ace_setup() which initialized all data structures, reads the CF
   *    id structure and registers the device.
   *
   * Processing:
   *    Just about all of the heavy lifting in this driver is performed by
   *    a Finite State Machine (FSM).  The driver needs to wait on a number
   *    of events; some raised by interrupts, some which need to be polled
   *    for.  Describing all of the behaviour in a FSM seems to be the
   *    easiest way to keep the complexity low and make it easy to
   *    understand what the driver is doing.  If the block ops or the
   *    request function need to interact with the hardware, then they
   *    simply need to flag the request and kick of FSM processing.
   *
   *    The FSM itself is atomic-safe code which can be run from any
   *    context.  The general process flow is:
   *    1. obtain the ace->lock spinlock.
   *    2. loop on ace_fsm_dostate() until the ace->fsm_continue flag is
   *       cleared.
   *    3. release the lock.
   *
   *    Individual states do not sleep in any way.  If a condition needs to
   *    be waited for then the state much clear the fsm_continue flag and
   *    either schedule the FSM to be run again at a later time, or expect
   *    an interrupt to call the FSM when the desired condition is met.
   *
   *    In normal operation, the FSM is processed at interrupt context
   *    either when the driver's tasklet is scheduled, or when an irq is
   *    raised by the hardware.  The tasklet can be scheduled at any time.
   *    The request method in particular schedules the tasklet when a new
   *    request has been indicated by the block layer.  Once started, the
   *    FSM proceeds as far as it can processing the request until it
   *    needs on a hardware event.  At this point, it must yield execution.
   *
   *    A state has two options when yielding execution:
   *    1. ace_fsm_yield()
   *       - Call if need to poll for event.
   *       - clears the fsm_continue flag to exit the processing loop
   *       - reschedules the tasklet to run again as soon as possible
   *    2. ace_fsm_yieldirq()
   *       - Call if an irq is expected from the HW
   *       - clears the fsm_continue flag to exit the processing loop
   *       - does not reschedule the tasklet so the FSM will not be processed
   *         again until an irq is received.
   *    After calling a yield function, the state must return control back
   *    to the FSM main loop.
   *
   *    Additionally, the driver maintains a kernel timer which can process
   *    the FSM.  If the FSM gets stalled, typically due to a missed
   *    interrupt, then the kernel timer will expire and the driver can
   *    continue where it left off.
   *
   * To Do:
   *    - Add FPGA configuration control interface.
   *    - Request major number from lanana
   */
  
  #undef DEBUG
  
  #include <linux/module.h>
  #include <linux/ctype.h>
  #include <linux/init.h>
  #include <linux/interrupt.h>
  #include <linux/errno.h>
  #include <linux/kernel.h>
  #include <linux/delay.h>
  #include <linux/slab.h>
  #include <linux/blkdev.h>

  #include <linux/mutex.h>

  #include <linux/ata.h>

  #include <linux/hdreg.h>
  #include <linux/platform_device.h>

  #if defined(CONFIG_OF)

  #include <linux/of_address.h>

  #include <linux/of_device.h>
  #include <linux/of_platform.h>
  #endif

  
  MODULE_AUTHOR("Grant Likely <grant.likely@secretlab.ca>");
  MODULE_DESCRIPTION("Xilinx SystemACE device driver");
  MODULE_LICENSE("GPL");
  
  /* SystemACE register definitions */
  #define ACE_BUSMODE (0x00)
  
  #define ACE_STATUS (0x04)
  #define ACE_STATUS_CFGLOCK      (0x00000001)
  #define ACE_STATUS_MPULOCK      (0x00000002)
  #define ACE_STATUS_CFGERROR     (0x00000004)	/* config controller error */
  #define ACE_STATUS_CFCERROR     (0x00000008)	/* CF controller error */
  #define ACE_STATUS_CFDETECT     (0x00000010)
  #define ACE_STATUS_DATABUFRDY   (0x00000020)
  #define ACE_STATUS_DATABUFMODE  (0x00000040)
  #define ACE_STATUS_CFGDONE      (0x00000080)
  #define ACE_STATUS_RDYFORCFCMD  (0x00000100)
  #define ACE_STATUS_CFGMODEPIN   (0x00000200)
  #define ACE_STATUS_CFGADDR_MASK (0x0000e000)
  #define ACE_STATUS_CFBSY        (0x00020000)
  #define ACE_STATUS_CFRDY        (0x00040000)
  #define ACE_STATUS_CFDWF        (0x00080000)
  #define ACE_STATUS_CFDSC        (0x00100000)
  #define ACE_STATUS_CFDRQ        (0x00200000)
  #define ACE_STATUS_CFCORR       (0x00400000)
  #define ACE_STATUS_CFERR        (0x00800000)
  
  #define ACE_ERROR (0x08)
  #define ACE_CFGLBA (0x0c)
  #define ACE_MPULBA (0x10)
  
  #define ACE_SECCNTCMD (0x14)
  #define ACE_SECCNTCMD_RESET      (0x0100)
  #define ACE_SECCNTCMD_IDENTIFY   (0x0200)
  #define ACE_SECCNTCMD_READ_DATA  (0x0300)
  #define ACE_SECCNTCMD_WRITE_DATA (0x0400)
  #define ACE_SECCNTCMD_ABORT      (0x0600)
  
  #define ACE_VERSION (0x16)
  #define ACE_VERSION_REVISION_MASK (0x00FF)
  #define ACE_VERSION_MINOR_MASK    (0x0F00)
  #define ACE_VERSION_MAJOR_MASK    (0xF000)
  
  #define ACE_CTRL (0x18)
  #define ACE_CTRL_FORCELOCKREQ   (0x0001)
  #define ACE_CTRL_LOCKREQ        (0x0002)
  #define ACE_CTRL_FORCECFGADDR   (0x0004)
  #define ACE_CTRL_FORCECFGMODE   (0x0008)
  #define ACE_CTRL_CFGMODE        (0x0010)
  #define ACE_CTRL_CFGSTART       (0x0020)
  #define ACE_CTRL_CFGSEL         (0x0040)
  #define ACE_CTRL_CFGRESET       (0x0080)
  #define ACE_CTRL_DATABUFRDYIRQ  (0x0100)
  #define ACE_CTRL_ERRORIRQ       (0x0200)
  #define ACE_CTRL_CFGDONEIRQ     (0x0400)
  #define ACE_CTRL_RESETIRQ       (0x0800)
  #define ACE_CTRL_CFGPROG        (0x1000)
  #define ACE_CTRL_CFGADDR_MASK   (0xe000)
  
  #define ACE_FATSTAT (0x1c)
  
  #define ACE_NUM_MINORS 16
  #define ACE_SECTOR_SIZE (512)
  #define ACE_FIFO_SIZE (32)
  #define ACE_BUF_PER_SECTOR (ACE_SECTOR_SIZE / ACE_FIFO_SIZE)

  #define ACE_BUS_WIDTH_8  0
  #define ACE_BUS_WIDTH_16 1

  struct ace_reg_ops;
  
  struct ace_device {
  	/* driver state data */
  	int id;
  	int media_change;
  	int users;
  	struct list_head list;
  
  	/* finite state machine data */
  	struct tasklet_struct fsm_tasklet;
  	uint fsm_task;		/* Current activity (ACE_TASK_*) */
  	uint fsm_state;		/* Current state (ACE_FSM_STATE_*) */
  	uint fsm_continue_flag;	/* cleared to exit FSM mainloop */
  	uint fsm_iter_num;
  	struct timer_list stall_timer;
  
  	/* Transfer state/result, use for both id and block request */
  	struct request *req;	/* request being processed */
  	void *data_ptr;		/* pointer to I/O buffer */
  	int data_count;		/* number of buffers remaining */
  	int data_result;	/* Result of transfer; 0 := success */
  
  	int id_req_count;	/* count of id requests */
  	int id_result;
  	struct completion id_completion;	/* used when id req finishes */
  	int in_irq;
  
  	/* Details of hardware device */

  	resource_size_t physaddr;

  	void __iomem *baseaddr;

  	int irq;
  	int bus_width;		/* 0 := 8 bit; 1 := 16 bit */
  	struct ace_reg_ops *reg_ops;
  	int lock_count;
  
  	/* Block device data structures */
  	spinlock_t lock;
  	struct device *dev;
  	struct request_queue *queue;
  	struct gendisk *gd;
  
  	/* Inserted CF card parameters */

  	u16 cf_id[ATA_ID_WORDS];

  };

  static DEFINE_MUTEX(xsysace_mutex);

  static int ace_major;
  
  /* ---------------------------------------------------------------------
   * Low level register access
   */
  
  struct ace_reg_ops {
  	u16(*in) (struct ace_device * ace, int reg);
  	void (*out) (struct ace_device * ace, int reg, u16 val);
  	void (*datain) (struct ace_device * ace);
  	void (*dataout) (struct ace_device * ace);
  };
  
  /* 8 Bit bus width */
  static u16 ace_in_8(struct ace_device *ace, int reg)
  {

  	void __iomem *r = ace->baseaddr + reg;

  	return in_8(r) | (in_8(r + 1) << 8);
  }
  
  static void ace_out_8(struct ace_device *ace, int reg, u16 val)
  {

  	void __iomem *r = ace->baseaddr + reg;

  	out_8(r, val);
  	out_8(r + 1, val >> 8);
  }
  
  static void ace_datain_8(struct ace_device *ace)
  {

  	void __iomem *r = ace->baseaddr + 0x40;

  	u8 *dst = ace->data_ptr;
  	int i = ACE_FIFO_SIZE;
  	while (i--)
  		*dst++ = in_8(r++);
  	ace->data_ptr = dst;
  }
  
  static void ace_dataout_8(struct ace_device *ace)
  {

  	void __iomem *r = ace->baseaddr + 0x40;

  	u8 *src = ace->data_ptr;
  	int i = ACE_FIFO_SIZE;
  	while (i--)
  		out_8(r++, *src++);
  	ace->data_ptr = src;
  }
  
  static struct ace_reg_ops ace_reg_8_ops = {
  	.in = ace_in_8,
  	.out = ace_out_8,
  	.datain = ace_datain_8,
  	.dataout = ace_dataout_8,
  };
  
  /* 16 bit big endian bus attachment */
  static u16 ace_in_be16(struct ace_device *ace, int reg)
  {
  	return in_be16(ace->baseaddr + reg);
  }
  
  static void ace_out_be16(struct ace_device *ace, int reg, u16 val)
  {
  	out_be16(ace->baseaddr + reg, val);
  }
  
  static void ace_datain_be16(struct ace_device *ace)
  {
  	int i = ACE_FIFO_SIZE / 2;
  	u16 *dst = ace->data_ptr;
  	while (i--)
  		*dst++ = in_le16(ace->baseaddr + 0x40);
  	ace->data_ptr = dst;
  }
  
  static void ace_dataout_be16(struct ace_device *ace)
  {
  	int i = ACE_FIFO_SIZE / 2;
  	u16 *src = ace->data_ptr;
  	while (i--)
  		out_le16(ace->baseaddr + 0x40, *src++);
  	ace->data_ptr = src;
  }
  
  /* 16 bit little endian bus attachment */
  static u16 ace_in_le16(struct ace_device *ace, int reg)
  {
  	return in_le16(ace->baseaddr + reg);
  }
  
  static void ace_out_le16(struct ace_device *ace, int reg, u16 val)
  {
  	out_le16(ace->baseaddr + reg, val);
  }
  
  static void ace_datain_le16(struct ace_device *ace)
  {
  	int i = ACE_FIFO_SIZE / 2;
  	u16 *dst = ace->data_ptr;
  	while (i--)
  		*dst++ = in_be16(ace->baseaddr + 0x40);
  	ace->data_ptr = dst;
  }
  
  static void ace_dataout_le16(struct ace_device *ace)
  {
  	int i = ACE_FIFO_SIZE / 2;
  	u16 *src = ace->data_ptr;
  	while (i--)
  		out_be16(ace->baseaddr + 0x40, *src++);
  	ace->data_ptr = src;
  }
  
  static struct ace_reg_ops ace_reg_be16_ops = {
  	.in = ace_in_be16,
  	.out = ace_out_be16,
  	.datain = ace_datain_be16,
  	.dataout = ace_dataout_be16,
  };
  
  static struct ace_reg_ops ace_reg_le16_ops = {
  	.in = ace_in_le16,
  	.out = ace_out_le16,
  	.datain = ace_datain_le16,
  	.dataout = ace_dataout_le16,
  };
  
  static inline u16 ace_in(struct ace_device *ace, int reg)
  {
  	return ace->reg_ops->in(ace, reg);
  }
  
  static inline u32 ace_in32(struct ace_device *ace, int reg)
  {
  	return ace_in(ace, reg) | (ace_in(ace, reg + 2) << 16);
  }
  
  static inline void ace_out(struct ace_device *ace, int reg, u16 val)
  {
  	ace->reg_ops->out(ace, reg, val);
  }
  
  static inline void ace_out32(struct ace_device *ace, int reg, u32 val)
  {
  	ace_out(ace, reg, val);
  	ace_out(ace, reg + 2, val >> 16);
  }
  
  /* ---------------------------------------------------------------------
   * Debug support functions
   */
  
  #if defined(DEBUG)
  static void ace_dump_mem(void *base, int len)
  {
  	const char *ptr = base;
  	int i, j;
  
  	for (i = 0; i < len; i += 16) {
  		printk(KERN_INFO "%.8x:", i);
  		for (j = 0; j < 16; j++) {
  			if (!(j % 4))
  				printk(" ");
  			printk("%.2x", ptr[i + j]);
  		}
  		printk(" ");
  		for (j = 0; j < 16; j++)
  			printk("%c", isprint(ptr[i + j]) ? ptr[i + j] : '.');
  		printk("
  ");
  	}
  }
  #else
  static inline void ace_dump_mem(void *base, int len)
  {
  }
  #endif
  
  static void ace_dump_regs(struct ace_device *ace)
  {

  	dev_info(ace->dev,
  		 "    ctrl:  %.8x  seccnt/cmd: %.4x      ver:%.4x
  "
  		 "    status:%.8x  mpu_lba:%.8x  busmode:%4x
  "
  		 "    error: %.8x  cfg_lba:%.8x  fatstat:%.4x
  ",

  		 ace_in32(ace, ACE_CTRL),
  		 ace_in(ace, ACE_SECCNTCMD),
  		 ace_in(ace, ACE_VERSION),
  		 ace_in32(ace, ACE_STATUS),
  		 ace_in32(ace, ACE_MPULBA),
  		 ace_in(ace, ACE_BUSMODE),
  		 ace_in32(ace, ACE_ERROR),
  		 ace_in32(ace, ACE_CFGLBA), ace_in(ace, ACE_FATSTAT));
  }

  static void ace_fix_driveid(u16 *id)

  {
  #if defined(__BIG_ENDIAN)

  	int i;
  
  	/* All half words have wrong byte order; swap the bytes */

  	for (i = 0; i < ATA_ID_WORDS; i++, id++)
  		*id = le16_to_cpu(*id);

  #endif
  }
  
  /* ---------------------------------------------------------------------
   * Finite State Machine (FSM) implementation
   */
  
  /* FSM tasks; used to direct state transitions */
  #define ACE_TASK_IDLE      0
  #define ACE_TASK_IDENTIFY  1
  #define ACE_TASK_READ      2
  #define ACE_TASK_WRITE     3
  #define ACE_FSM_NUM_TASKS  4
  
  /* FSM state definitions */
  #define ACE_FSM_STATE_IDLE               0
  #define ACE_FSM_STATE_REQ_LOCK           1
  #define ACE_FSM_STATE_WAIT_LOCK          2
  #define ACE_FSM_STATE_WAIT_CFREADY       3
  #define ACE_FSM_STATE_IDENTIFY_PREPARE   4
  #define ACE_FSM_STATE_IDENTIFY_TRANSFER  5
  #define ACE_FSM_STATE_IDENTIFY_COMPLETE  6
  #define ACE_FSM_STATE_REQ_PREPARE        7
  #define ACE_FSM_STATE_REQ_TRANSFER       8
  #define ACE_FSM_STATE_REQ_COMPLETE       9
  #define ACE_FSM_STATE_ERROR             10
  #define ACE_FSM_NUM_STATES              11
  
  /* Set flag to exit FSM loop and reschedule tasklet */
  static inline void ace_fsm_yield(struct ace_device *ace)
  {
  	dev_dbg(ace->dev, "ace_fsm_yield()
  ");
  	tasklet_schedule(&ace->fsm_tasklet);
  	ace->fsm_continue_flag = 0;
  }
  
  /* Set flag to exit FSM loop and wait for IRQ to reschedule tasklet */
  static inline void ace_fsm_yieldirq(struct ace_device *ace)
  {
  	dev_dbg(ace->dev, "ace_fsm_yieldirq()
  ");

  	if (!ace->irq)

  		/* No IRQ assigned, so need to poll */
  		tasklet_schedule(&ace->fsm_tasklet);
  	ace->fsm_continue_flag = 0;
  }
  
  /* Get the next read/write request; ending requests that we don't handle */

  static struct request *ace_get_next_request(struct request_queue *q)

  {
  	struct request *req;

  	while ((req = blk_peek_request(q)) != NULL) {

  		if (!blk_rq_is_passthrough(req))

  			break;

  		blk_start_request(req);

  		__blk_end_request_all(req, BLK_STS_IOERR);

  	}
  	return req;
  }
  
  static void ace_fsm_dostate(struct ace_device *ace)
  {
  	struct request *req;
  	u32 status;
  	u16 val;
  	int count;

  
  #if defined(DEBUG)
  	dev_dbg(ace->dev, "fsm_state=%i, id_req_count=%i
  ",
  		ace->fsm_state, ace->id_req_count);
  #endif

  	/* Verify that there is actually a CF in the slot. If not, then
  	 * bail out back to the idle state and wake up all the waiters */
  	status = ace_in32(ace, ACE_STATUS);
  	if ((status & ACE_STATUS_CFDETECT) == 0) {
  		ace->fsm_state = ACE_FSM_STATE_IDLE;
  		ace->media_change = 1;
  		set_capacity(ace->gd, 0);
  		dev_info(ace->dev, "No CF in slot
  ");

  		/* Drop all in-flight and pending requests */
  		if (ace->req) {

  			__blk_end_request_all(ace->req, BLK_STS_IOERR);

  			ace->req = NULL;
  		}

  		while ((req = blk_fetch_request(ace->queue)) != NULL)

  			__blk_end_request_all(req, BLK_STS_IOERR);

  
  		/* Drop back to IDLE state and notify waiters */
  		ace->fsm_state = ACE_FSM_STATE_IDLE;
  		ace->id_result = -EIO;
  		while (ace->id_req_count) {
  			complete(&ace->id_completion);
  			ace->id_req_count--;
  		}
  	}

  	switch (ace->fsm_state) {
  	case ACE_FSM_STATE_IDLE:
  		/* See if there is anything to do */
  		if (ace->id_req_count || ace_get_next_request(ace->queue)) {
  			ace->fsm_iter_num++;
  			ace->fsm_state = ACE_FSM_STATE_REQ_LOCK;
  			mod_timer(&ace->stall_timer, jiffies + HZ);
  			if (!timer_pending(&ace->stall_timer))
  				add_timer(&ace->stall_timer);
  			break;
  		}
  		del_timer(&ace->stall_timer);
  		ace->fsm_continue_flag = 0;
  		break;
  
  	case ACE_FSM_STATE_REQ_LOCK:
  		if (ace_in(ace, ACE_STATUS) & ACE_STATUS_MPULOCK) {
  			/* Already have the lock, jump to next state */
  			ace->fsm_state = ACE_FSM_STATE_WAIT_CFREADY;
  			break;
  		}
  
  		/* Request the lock */
  		val = ace_in(ace, ACE_CTRL);
  		ace_out(ace, ACE_CTRL, val | ACE_CTRL_LOCKREQ);
  		ace->fsm_state = ACE_FSM_STATE_WAIT_LOCK;
  		break;
  
  	case ACE_FSM_STATE_WAIT_LOCK:
  		if (ace_in(ace, ACE_STATUS) & ACE_STATUS_MPULOCK) {
  			/* got the lock; move to next state */
  			ace->fsm_state = ACE_FSM_STATE_WAIT_CFREADY;
  			break;
  		}
  
  		/* wait a bit for the lock */
  		ace_fsm_yield(ace);
  		break;
  
  	case ACE_FSM_STATE_WAIT_CFREADY:
  		status = ace_in32(ace, ACE_STATUS);
  		if (!(status & ACE_STATUS_RDYFORCFCMD) ||
  		    (status & ACE_STATUS_CFBSY)) {
  			/* CF card isn't ready; it needs to be polled */
  			ace_fsm_yield(ace);
  			break;
  		}
  
  		/* Device is ready for command; determine what to do next */
  		if (ace->id_req_count)
  			ace->fsm_state = ACE_FSM_STATE_IDENTIFY_PREPARE;
  		else
  			ace->fsm_state = ACE_FSM_STATE_REQ_PREPARE;
  		break;
  
  	case ACE_FSM_STATE_IDENTIFY_PREPARE:
  		/* Send identify command */
  		ace->fsm_task = ACE_TASK_IDENTIFY;

  		ace->data_ptr = ace->cf_id;

  		ace->data_count = ACE_BUF_PER_SECTOR;
  		ace_out(ace, ACE_SECCNTCMD, ACE_SECCNTCMD_IDENTIFY);
  
  		/* As per datasheet, put config controller in reset */
  		val = ace_in(ace, ACE_CTRL);
  		ace_out(ace, ACE_CTRL, val | ACE_CTRL_CFGRESET);
  
  		/* irq handler takes over from this point; wait for the
  		 * transfer to complete */
  		ace->fsm_state = ACE_FSM_STATE_IDENTIFY_TRANSFER;
  		ace_fsm_yieldirq(ace);
  		break;
  
  	case ACE_FSM_STATE_IDENTIFY_TRANSFER:
  		/* Check that the sysace is ready to receive data */
  		status = ace_in32(ace, ACE_STATUS);
  		if (status & ACE_STATUS_CFBSY) {
  			dev_dbg(ace->dev, "CFBSY set; t=%i iter=%i dc=%i
  ",
  				ace->fsm_task, ace->fsm_iter_num,
  				ace->data_count);
  			ace_fsm_yield(ace);
  			break;
  		}
  		if (!(status & ACE_STATUS_DATABUFRDY)) {
  			ace_fsm_yield(ace);
  			break;
  		}
  
  		/* Transfer the next buffer */
  		ace->reg_ops->datain(ace);
  		ace->data_count--;
  
  		/* If there are still buffers to be transfers; jump out here */
  		if (ace->data_count != 0) {
  			ace_fsm_yieldirq(ace);
  			break;
  		}
  
  		/* transfer finished; kick state machine */
  		dev_dbg(ace->dev, "identify finished
  ");
  		ace->fsm_state = ACE_FSM_STATE_IDENTIFY_COMPLETE;
  		break;
  
  	case ACE_FSM_STATE_IDENTIFY_COMPLETE:

  		ace_fix_driveid(ace->cf_id);
  		ace_dump_mem(ace->cf_id, 512);	/* Debug: Dump out disk ID */

  
  		if (ace->data_result) {

  			/* Error occurred, disable the disk */

  			ace->media_change = 1;
  			set_capacity(ace->gd, 0);
  			dev_err(ace->dev, "error fetching CF id (%i)
  ",
  				ace->data_result);
  		} else {
  			ace->media_change = 0;
  
  			/* Record disk parameters */

  			set_capacity(ace->gd,

  				ata_id_u32(ace->cf_id, ATA_ID_LBA_CAPACITY));

  			dev_info(ace->dev, "capacity: %i sectors
  ",

  				ata_id_u32(ace->cf_id, ATA_ID_LBA_CAPACITY));

  		}
  
  		/* We're done, drop to IDLE state and notify waiters */
  		ace->fsm_state = ACE_FSM_STATE_IDLE;
  		ace->id_result = ace->data_result;
  		while (ace->id_req_count) {
  			complete(&ace->id_completion);
  			ace->id_req_count--;
  		}
  		break;
  
  	case ACE_FSM_STATE_REQ_PREPARE:
  		req = ace_get_next_request(ace->queue);
  		if (!req) {
  			ace->fsm_state = ACE_FSM_STATE_IDLE;
  			break;
  		}

  		blk_start_request(req);

  
  		/* Okay, it's a data request, set it up for transfer */
  		dev_dbg(ace->dev,

  			"request: sec=%llx hcnt=%x, ccnt=%x, dir=%i
  ",

  			(unsigned long long)blk_rq_pos(req),
  			blk_rq_sectors(req), blk_rq_cur_sectors(req),
  			rq_data_dir(req));

  
  		ace->req = req;

  		ace->data_ptr = bio_data(req->bio);

  		ace->data_count = blk_rq_cur_sectors(req) * ACE_BUF_PER_SECTOR;
  		ace_out32(ace, ACE_MPULBA, blk_rq_pos(req) & 0x0FFFFFFF);

  		count = blk_rq_sectors(req);

  		if (rq_data_dir(req)) {
  			/* Kick off write request */
  			dev_dbg(ace->dev, "write data
  ");
  			ace->fsm_task = ACE_TASK_WRITE;
  			ace_out(ace, ACE_SECCNTCMD,
  				count | ACE_SECCNTCMD_WRITE_DATA);
  		} else {
  			/* Kick off read request */
  			dev_dbg(ace->dev, "read data
  ");
  			ace->fsm_task = ACE_TASK_READ;
  			ace_out(ace, ACE_SECCNTCMD,
  				count | ACE_SECCNTCMD_READ_DATA);
  		}
  
  		/* As per datasheet, put config controller in reset */
  		val = ace_in(ace, ACE_CTRL);
  		ace_out(ace, ACE_CTRL, val | ACE_CTRL_CFGRESET);
  
  		/* Move to the transfer state.  The systemace will raise
  		 * an interrupt once there is something to do
  		 */
  		ace->fsm_state = ACE_FSM_STATE_REQ_TRANSFER;
  		if (ace->fsm_task == ACE_TASK_READ)
  			ace_fsm_yieldirq(ace);	/* wait for data ready */
  		break;
  
  	case ACE_FSM_STATE_REQ_TRANSFER:
  		/* Check that the sysace is ready to receive data */
  		status = ace_in32(ace, ACE_STATUS);
  		if (status & ACE_STATUS_CFBSY) {
  			dev_dbg(ace->dev,
  				"CFBSY set; t=%i iter=%i c=%i dc=%i irq=%i
  ",
  				ace->fsm_task, ace->fsm_iter_num,

  				blk_rq_cur_sectors(ace->req) * 16,

  				ace->data_count, ace->in_irq);
  			ace_fsm_yield(ace);	/* need to poll CFBSY bit */
  			break;
  		}
  		if (!(status & ACE_STATUS_DATABUFRDY)) {
  			dev_dbg(ace->dev,
  				"DATABUF not set; t=%i iter=%i c=%i dc=%i irq=%i
  ",
  				ace->fsm_task, ace->fsm_iter_num,

  				blk_rq_cur_sectors(ace->req) * 16,

  				ace->data_count, ace->in_irq);
  			ace_fsm_yieldirq(ace);
  			break;
  		}
  
  		/* Transfer the next buffer */

  		if (ace->fsm_task == ACE_TASK_WRITE)
  			ace->reg_ops->dataout(ace);
  		else
  			ace->reg_ops->datain(ace);
  		ace->data_count--;
  
  		/* If there are still buffers to be transfers; jump out here */
  		if (ace->data_count != 0) {
  			ace_fsm_yieldirq(ace);
  			break;
  		}
  
  		/* bio finished; is there another one? */

  		if (__blk_end_request_cur(ace->req, BLK_STS_OK)) {

  			/* dev_dbg(ace->dev, "next block; h=%u c=%u
  ",
  			 *      blk_rq_sectors(ace->req),

  			 *      blk_rq_cur_sectors(ace->req));

  			 */

  			ace->data_ptr = bio_data(ace->req->bio);

  			ace->data_count = blk_rq_cur_sectors(ace->req) * 16;

  			ace_fsm_yieldirq(ace);
  			break;
  		}
  
  		ace->fsm_state = ACE_FSM_STATE_REQ_COMPLETE;
  		break;
  
  	case ACE_FSM_STATE_REQ_COMPLETE:

  		ace->req = NULL;
  
  		/* Finished request; go to idle state */
  		ace->fsm_state = ACE_FSM_STATE_IDLE;
  		break;
  
  	default:
  		ace->fsm_state = ACE_FSM_STATE_IDLE;
  		break;
  	}
  }
  
  static void ace_fsm_tasklet(unsigned long data)
  {
  	struct ace_device *ace = (void *)data;
  	unsigned long flags;
  
  	spin_lock_irqsave(&ace->lock, flags);
  
  	/* Loop over state machine until told to stop */
  	ace->fsm_continue_flag = 1;
  	while (ace->fsm_continue_flag)
  		ace_fsm_dostate(ace);
  
  	spin_unlock_irqrestore(&ace->lock, flags);
  }
  
  static void ace_stall_timer(unsigned long data)
  {
  	struct ace_device *ace = (void *)data;
  	unsigned long flags;
  
  	dev_warn(ace->dev,
  		 "kicking stalled fsm; state=%i task=%i iter=%i dc=%i
  ",
  		 ace->fsm_state, ace->fsm_task, ace->fsm_iter_num,
  		 ace->data_count);
  	spin_lock_irqsave(&ace->lock, flags);
  
  	/* Rearm the stall timer *before* entering FSM (which may then
  	 * delete the timer) */
  	mod_timer(&ace->stall_timer, jiffies + HZ);
  
  	/* Loop over state machine until told to stop */
  	ace->fsm_continue_flag = 1;
  	while (ace->fsm_continue_flag)
  		ace_fsm_dostate(ace);
  
  	spin_unlock_irqrestore(&ace->lock, flags);
  }
  
  /* ---------------------------------------------------------------------
   * Interrupt handling routines
   */
  static int ace_interrupt_checkstate(struct ace_device *ace)
  {
  	u32 sreg = ace_in32(ace, ACE_STATUS);
  	u16 creg = ace_in(ace, ACE_CTRL);

  	/* Check for error occurrence */

  	if ((sreg & (ACE_STATUS_CFGERROR | ACE_STATUS_CFCERROR)) &&
  	    (creg & ACE_CTRL_ERRORIRQ)) {
  		dev_err(ace->dev, "transfer failure
  ");
  		ace_dump_regs(ace);
  		return -EIO;
  	}
  
  	return 0;
  }
  
  static irqreturn_t ace_interrupt(int irq, void *dev_id)
  {
  	u16 creg;
  	struct ace_device *ace = dev_id;
  
  	/* be safe and get the lock */
  	spin_lock(&ace->lock);
  	ace->in_irq = 1;
  
  	/* clear the interrupt */
  	creg = ace_in(ace, ACE_CTRL);
  	ace_out(ace, ACE_CTRL, creg | ACE_CTRL_RESETIRQ);
  	ace_out(ace, ACE_CTRL, creg);
  
  	/* check for IO failures */
  	if (ace_interrupt_checkstate(ace))
  		ace->data_result = -EIO;
  
  	if (ace->fsm_task == 0) {
  		dev_err(ace->dev,
  			"spurious irq; stat=%.8x ctrl=%.8x cmd=%.4x
  ",
  			ace_in32(ace, ACE_STATUS), ace_in32(ace, ACE_CTRL),
  			ace_in(ace, ACE_SECCNTCMD));
  		dev_err(ace->dev, "fsm_task=%i fsm_state=%i data_count=%i
  ",
  			ace->fsm_task, ace->fsm_state, ace->data_count);
  	}
  
  	/* Loop over state machine until told to stop */
  	ace->fsm_continue_flag = 1;
  	while (ace->fsm_continue_flag)
  		ace_fsm_dostate(ace);
  
  	/* done with interrupt; drop the lock */
  	ace->in_irq = 0;
  	spin_unlock(&ace->lock);
  
  	return IRQ_HANDLED;
  }
  
  /* ---------------------------------------------------------------------
   * Block ops
   */

  static void ace_request(struct request_queue * q)

  {
  	struct request *req;
  	struct ace_device *ace;
  
  	req = ace_get_next_request(q);
  
  	if (req) {
  		ace = req->rq_disk->private_data;
  		tasklet_schedule(&ace->fsm_tasklet);
  	}
  }

  static unsigned int ace_check_events(struct gendisk *gd, unsigned int clearing)

  {
  	struct ace_device *ace = gd->private_data;

  	dev_dbg(ace->dev, "ace_check_events(): %i
  ", ace->media_change);

  	return ace->media_change ? DISK_EVENT_MEDIA_CHANGE : 0;

  }
  
  static int ace_revalidate_disk(struct gendisk *gd)
  {
  	struct ace_device *ace = gd->private_data;
  	unsigned long flags;
  
  	dev_dbg(ace->dev, "ace_revalidate_disk()
  ");
  
  	if (ace->media_change) {
  		dev_dbg(ace->dev, "requesting cf id and scheduling tasklet
  ");
  
  		spin_lock_irqsave(&ace->lock, flags);
  		ace->id_req_count++;
  		spin_unlock_irqrestore(&ace->lock, flags);
  
  		tasklet_schedule(&ace->fsm_tasklet);
  		wait_for_completion(&ace->id_completion);
  	}
  
  	dev_dbg(ace->dev, "revalidate complete
  ");
  	return ace->id_result;
  }

  static int ace_open(struct block_device *bdev, fmode_t mode)

  {

  	struct ace_device *ace = bdev->bd_disk->private_data;

  	unsigned long flags;
  
  	dev_dbg(ace->dev, "ace_open() users=%i
  ", ace->users + 1);

  	mutex_lock(&xsysace_mutex);

  	spin_lock_irqsave(&ace->lock, flags);
  	ace->users++;
  	spin_unlock_irqrestore(&ace->lock, flags);

  	check_disk_change(bdev);

  	mutex_unlock(&xsysace_mutex);

  	return 0;
  }

  static void ace_release(struct gendisk *disk, fmode_t mode)

  {

  	struct ace_device *ace = disk->private_data;

  	unsigned long flags;
  	u16 val;
  
  	dev_dbg(ace->dev, "ace_release() users=%i
  ", ace->users - 1);

  	mutex_lock(&xsysace_mutex);

  	spin_lock_irqsave(&ace->lock, flags);
  	ace->users--;
  	if (ace->users == 0) {
  		val = ace_in(ace, ACE_CTRL);
  		ace_out(ace, ACE_CTRL, val & ~ACE_CTRL_LOCKREQ);
  	}
  	spin_unlock_irqrestore(&ace->lock, flags);

  	mutex_unlock(&xsysace_mutex);

  }

  static int ace_getgeo(struct block_device *bdev, struct hd_geometry *geo)

  {

  	struct ace_device *ace = bdev->bd_disk->private_data;

  	u16 *cf_id = ace->cf_id;

  	dev_dbg(ace->dev, "ace_getgeo()
  ");

  	geo->heads	= cf_id[ATA_ID_HEADS];
  	geo->sectors	= cf_id[ATA_ID_SECTORS];
  	geo->cylinders	= cf_id[ATA_ID_CYLS];

  
  	return 0;

  }

  static const struct block_device_operations ace_fops = {

  	.owner = THIS_MODULE,

  	.open = ace_open,
  	.release = ace_release,

  	.check_events = ace_check_events,

  	.revalidate_disk = ace_revalidate_disk,

  	.getgeo = ace_getgeo,

  };
  
  /* --------------------------------------------------------------------
   * SystemACE device setup/teardown code
   */

  static int ace_setup(struct ace_device *ace)

  {
  	u16 version;
  	u16 val;

  	int rc;

  	dev_dbg(ace->dev, "ace_setup(ace=0x%p)
  ", ace);

  	dev_dbg(ace->dev, "physaddr=0x%llx irq=%i
  ",
  		(unsigned long long)ace->physaddr, ace->irq);

  	spin_lock_init(&ace->lock);
  	init_completion(&ace->id_completion);
  
  	/*
  	 * Map the device
  	 */
  	ace->baseaddr = ioremap(ace->physaddr, 0x80);
  	if (!ace->baseaddr)
  		goto err_ioremap;

  	/*
  	 * Initialize the state machine tasklet and stall timer
  	 */
  	tasklet_init(&ace->fsm_tasklet, ace_fsm_tasklet, (unsigned long)ace);
  	setup_timer(&ace->stall_timer, ace_stall_timer, (unsigned long)ace);
  
  	/*
  	 * Initialize the request queue
  	 */
  	ace->queue = blk_init_queue(ace_request, &ace->lock);
  	if (ace->queue == NULL)
  		goto err_blk_initq;

  	blk_queue_logical_block_size(ace->queue, 512);

  	blk_queue_bounce_limit(ace->queue, BLK_BOUNCE_HIGH);

  
  	/*
  	 * Allocate and initialize GD structure
  	 */
  	ace->gd = alloc_disk(ACE_NUM_MINORS);
  	if (!ace->gd)
  		goto err_alloc_disk;
  
  	ace->gd->major = ace_major;
  	ace->gd->first_minor = ace->id * ACE_NUM_MINORS;
  	ace->gd->fops = &ace_fops;
  	ace->gd->queue = ace->queue;
  	ace->gd->private_data = ace;
  	snprintf(ace->gd->disk_name, 32, "xs%c", ace->id + 'a');
  
  	/* set bus width */

  	if (ace->bus_width == ACE_BUS_WIDTH_16) {

  		/* 0x0101 should work regardless of endianess */
  		ace_out_le16(ace, ACE_BUSMODE, 0x0101);
  
  		/* read it back to determine endianess */
  		if (ace_in_le16(ace, ACE_BUSMODE) == 0x0001)
  			ace->reg_ops = &ace_reg_le16_ops;
  		else
  			ace->reg_ops = &ace_reg_be16_ops;
  	} else {
  		ace_out_8(ace, ACE_BUSMODE, 0x00);
  		ace->reg_ops = &ace_reg_8_ops;
  	}
  
  	/* Make sure version register is sane */
  	version = ace_in(ace, ACE_VERSION);
  	if ((version == 0) || (version == 0xFFFF))
  		goto err_read;
  
  	/* Put sysace in a sane state by clearing most control reg bits */
  	ace_out(ace, ACE_CTRL, ACE_CTRL_FORCECFGMODE |
  		ACE_CTRL_DATABUFRDYIRQ | ACE_CTRL_ERRORIRQ);

  	/* Now we can hook up the irq handler */

  	if (ace->irq) {

  		rc = request_irq(ace->irq, ace_interrupt, 0, "systemace", ace);
  		if (rc) {
  			/* Failure - fall back to polled mode */
  			dev_err(ace->dev, "request_irq failed
  ");

  			ace->irq = 0;

  		}
  	}

  	/* Enable interrupts */
  	val = ace_in(ace, ACE_CTRL);
  	val |= ACE_CTRL_DATABUFRDYIRQ | ACE_CTRL_ERRORIRQ;
  	ace_out(ace, ACE_CTRL, val);

  	/* Print the identification */
  	dev_info(ace->dev, "Xilinx SystemACE revision %i.%i.%i
  ",
  		 (version >> 12) & 0xf, (version >> 8) & 0x0f, version & 0xff);

  	dev_dbg(ace->dev, "physaddr 0x%llx, mapped to 0x%p, irq=%i
  ",
  		(unsigned long long) ace->physaddr, ace->baseaddr, ace->irq);

  
  	ace->media_change = 1;
  	ace_revalidate_disk(ace->gd);
  
  	/* Make the sysace device 'live' */
  	add_disk(ace->gd);
  
  	return 0;

  err_read:

  	put_disk(ace->gd);

  err_alloc_disk:

  	blk_cleanup_queue(ace->queue);

  err_blk_initq:

  	iounmap(ace->baseaddr);

  err_ioremap:

  	dev_info(ace->dev, "xsysace: error initializing device at 0x%llx
  ",
  		 (unsigned long long) ace->physaddr);

  	return -ENOMEM;
  }

  static void ace_teardown(struct ace_device *ace)

  {
  	if (ace->gd) {
  		del_gendisk(ace->gd);
  		put_disk(ace->gd);
  	}
  
  	if (ace->queue)
  		blk_cleanup_queue(ace->queue);
  
  	tasklet_kill(&ace->fsm_tasklet);

  	if (ace->irq)

  		free_irq(ace->irq, ace);
  
  	iounmap(ace->baseaddr);
  }

  static int ace_alloc(struct device *dev, int id, resource_size_t physaddr,
  		     int irq, int bus_width)

  {

  	struct ace_device *ace;

  	int rc;
  	dev_dbg(dev, "ace_alloc(%p)
  ", dev);

  	if (!physaddr) {
  		rc = -ENODEV;
  		goto err_noreg;
  	}

  	/* Allocate and initialize the ace device structure */

  	ace = kzalloc(sizeof(struct ace_device), GFP_KERNEL);

  	if (!ace) {
  		rc = -ENOMEM;

  		goto err_alloc;

  	}

  	ace->dev = dev;
  	ace->id = id;
  	ace->physaddr = physaddr;
  	ace->irq = irq;
  	ace->bus_width = bus_width;

  	/* Call the setup code */

  	rc = ace_setup(ace);
  	if (rc)

  		goto err_setup;

  	dev_set_drvdata(dev, ace);

  	return 0;

  err_setup:

  	dev_set_drvdata(dev, NULL);

  	kfree(ace);

  err_alloc:
  err_noreg:

  	dev_err(dev, "could not initialize device, err=%i
  ", rc);
  	return rc;

  }

  static void ace_free(struct device *dev)

  {

  	struct ace_device *ace = dev_get_drvdata(dev);
  	dev_dbg(dev, "ace_free(%p)
  ", dev);

  
  	if (ace) {
  		ace_teardown(ace);

  		dev_set_drvdata(dev, NULL);

  		kfree(ace);
  	}

  }
  
  /* ---------------------------------------------------------------------
   * Platform Bus Support
   */

  static int ace_probe(struct platform_device *dev)

  {

  	resource_size_t physaddr = 0;

  	int bus_width = ACE_BUS_WIDTH_16; /* FIXME: should not be hard coded */

  	u32 id = dev->id;

  	int irq = 0;

  	int i;
  
  	dev_dbg(&dev->dev, "ace_probe(%p)
  ", dev);

  	/* device id and bus width */

  	if (of_property_read_u32(dev->dev.of_node, "port-number", &id))

  		id = 0;
  	if (of_find_property(dev->dev.of_node, "8-bit", NULL))
  		bus_width = ACE_BUS_WIDTH_8;

  	for (i = 0; i < dev->num_resources; i++) {
  		if (dev->resource[i].flags & IORESOURCE_MEM)
  			physaddr = dev->resource[i].start;
  		if (dev->resource[i].flags & IORESOURCE_IRQ)
  			irq = dev->resource[i].start;
  	}

  	/* Call the bus-independent setup code */

  	return ace_alloc(&dev->dev, id, physaddr, irq, bus_width);
  }

  /*
   * Platform bus remove() method
   */

  static int ace_remove(struct platform_device *dev)

  {
  	ace_free(&dev->dev);

  	return 0;
  }

  #if defined(CONFIG_OF)

  /* Match table for of_platform binding */

  static const struct of_device_id ace_of_match[] = {

  	{ .compatible = "xlnx,opb-sysace-1.00.b", },
  	{ .compatible = "xlnx,opb-sysace-1.00.c", },
  	{ .compatible = "xlnx,xps-sysace-1.00.a", },

  	{ .compatible = "xlnx,sysace", },

  	{},
  };
  MODULE_DEVICE_TABLE(of, ace_of_match);

  #else /* CONFIG_OF */
  #define ace_of_match NULL
  #endif /* CONFIG_OF */

  static struct platform_driver ace_platform_driver = {
  	.probe = ace_probe,

  	.remove = ace_remove,

  	.driver = {

  		.name = "xsysace",

  		.of_match_table = ace_of_match,

  	},
  };

  /* ---------------------------------------------------------------------

   * Module init/exit routines
   */
  static int __init ace_init(void)
  {

  	int rc;

  	ace_major = register_blkdev(ace_major, "xsysace");
  	if (ace_major <= 0) {

  		rc = -ENOMEM;
  		goto err_blk;

  	}

  	rc = platform_driver_register(&ace_platform_driver);
  	if (rc)

  		goto err_plat;
  
  	pr_info("Xilinx SystemACE device driver, major=%i
  ", ace_major);
  	return 0;

  err_plat:

  	unregister_blkdev(ace_major, "xsysace");

  err_blk:

  	printk(KERN_ERR "xsysace: registration failed; err=%i
  ", rc);
  	return rc;

  }

  module_init(ace_init);

  
  static void __exit ace_exit(void)
  {
  	pr_debug("Unregistering Xilinx SystemACE driver
  ");

  	platform_driver_unregister(&ace_platform_driver);

  	unregister_blkdev(ace_major, "xsysace");

  }

  module_exit(ace_exit);