Add support for Xilinx SystemACE CompactFlash interface

Tested on Xilinx Virtex ppc405, Katmai 440SPe, and Microblaze

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Acked-by: Stefan Roese <sr@denx.de>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: John William <jwilliams@itee.uq.edu.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 1166 insertions, 0 deletions

diff --git a/drivers/block/xsysace.c b/drivers/block/xsysace.c
new file mode 100644
index 000000000000..1cddfff9ae6f
--- /dev/null
+++ b/drivers/block/xsysace.c
@@ -0,0 +1,1166 @@
+/*
+ * 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/hdreg.h>
+#include <linux/platform_device.h>
+
+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)
+
+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 */
+        unsigned long physaddr;
+        void *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 */
+        struct hd_driveid cf_id;
+};
+
+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 *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 *r = ace->baseaddr + reg;
+        out_8(r, val);
+        out_8(r + 1, val >> 8);
+}
+
+static void ace_datain_8(struct ace_device *ace)
+{
+        void *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 *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("\n");
+        }
+}
+#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\n"
+                 "    status:%.8x  mpu_lba:%.8x  busmode:%4x\n"
+                 "    error: %.8x  cfg_lba:%.8x  fatstat:%.4x\n",
+                 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));
+}
+
+void ace_fix_driveid(struct hd_driveid *id)
+{
+#if defined(__BIG_ENDIAN)
+        u16 *buf = (void *)id;
+        int i;
+
+        /* All half words have wrong byte order; swap the bytes */
+        for (i = 0; i < sizeof(struct hd_driveid); i += 2, buf++)
+                *buf = le16_to_cpu(*buf);
+
+        /* Some of the data values are 32bit; swap the half words  */
+        id->lba_capacity = ((id->lba_capacity >> 16) & 0x0000FFFF) |
+            ((id->lba_capacity << 16) & 0xFFFF0000);
+        id->spg = ((id->spg >> 16) & 0x0000FFFF) |
+            ((id->spg << 16) & 0xFFFF0000);
+#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()\n");
+        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()\n");
+
+        if (ace->irq == NO_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 */
+struct request *ace_get_next_request(request_queue_t * q)
+{
+        struct request *req;
+
+        while ((req = elv_next_request(q)) != NULL) {
+                if (blk_fs_request(req))
+                        break;
+                end_request(req, 0);
+        }
+        return req;
+}
+
+static void ace_fsm_dostate(struct ace_device *ace)
+{
+        struct request *req;
+        u32 status;
+        u16 val;
+        int count;
+        int i;
+
+#if defined(DEBUG)
+        dev_dbg(ace->dev, "fsm_state=%i, id_req_count=%i\n",
+                ace->fsm_state, ace->id_req_count);
+#endif
+
+        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\n",
+                                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\n");
+                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 occured, disable the disk */
+                        ace->media_change = 1;
+                        set_capacity(ace->gd, 0);
+                        dev_err(ace->dev, "error fetching CF id (%i)\n",
+                                ace->data_result);
+                } else {
+                        ace->media_change = 0;
+
+                        /* Record disk parameters */
+                        set_capacity(ace->gd, ace->cf_id.lba_capacity);
+                        dev_info(ace->dev, "capacity: %i sectors\n",
+                                 ace->cf_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;
+                }
+
+                /* Okay, it's a data request, set it up for transfer */
+                dev_dbg(ace->dev,
+                        "request: sec=%lx hcnt=%lx, ccnt=%x, dir=%i\n",
+                        req->sector, req->hard_nr_sectors,
+                        req->current_nr_sectors, rq_data_dir(req));
+
+                ace->req = req;
+                ace->data_ptr = req->buffer;
+                ace->data_count = req->current_nr_sectors * ACE_BUF_PER_SECTOR;
+                ace_out32(ace, ACE_MPULBA, req->sector & 0x0FFFFFFF);
+
+                count = req->hard_nr_sectors;
+                if (rq_data_dir(req)) {
+                        /* Kick off write request */
+                        dev_dbg(ace->dev, "write data\n");
+                        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\n");
+                        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\n",
+                                ace->fsm_task, ace->fsm_iter_num,
+                                ace->req->current_nr_sectors * 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\n",
+                                ace->fsm_task, ace->fsm_iter_num,
+                                ace->req->current_nr_sectors * 16,
+                                ace->data_count, ace->in_irq);
+                        ace_fsm_yieldirq(ace);
+                        break;
+                }
+
+                /* Transfer the next buffer */
+                i = 16;
+                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? */
+                i = ace->req->current_nr_sectors;
+                if (end_that_request_first(ace->req, 1, i)) {
+                        /* dev_dbg(ace->dev, "next block; h=%li c=%i\n",
+                         *      ace->req->hard_nr_sectors,
+                         *      ace->req->current_nr_sectors);
+                         */
+                        ace->data_ptr = ace->req->buffer;
+                        ace->data_count = ace->req->current_nr_sectors * 16;
+                        ace_fsm_yieldirq(ace);
+                        break;
+                }
+
+                ace->fsm_state = ACE_FSM_STATE_REQ_COMPLETE;
+                break;
+
+        case ACE_FSM_STATE_REQ_COMPLETE:
+                /* Complete the block request */
+                blkdev_dequeue_request(ace->req);
+                end_that_request_last(ace->req, 1);
+                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\n",
+                 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 occurance */
+        if ((sreg & (ACE_STATUS_CFGERROR | ACE_STATUS_CFCERROR)) &&
+            (creg & ACE_CTRL_ERRORIRQ)) {
+                dev_err(ace->dev, "transfer failure\n");
+                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\n",
+                        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\n",
+                        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(request_queue_t * 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 int ace_media_changed(struct gendisk *gd)
+{
+        struct ace_device *ace = gd->private_data;
+        dev_dbg(ace->dev, "ace_media_changed(): %i\n", ace->media_change);
+
+        return ace->media_change;
+}
+
+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()\n");
+
+        if (ace->media_change) {
+                dev_dbg(ace->dev, "requesting cf id and scheduling tasklet\n");
+
+                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\n");
+        return ace->id_result;
+}
+
+static int ace_open(struct inode *inode, struct file *filp)
+{
+        struct ace_device *ace = inode->i_bdev->bd_disk->private_data;
+        unsigned long flags;
+
+        dev_dbg(ace->dev, "ace_open() users=%i\n", ace->users + 1);
+
+        filp->private_data = ace;
+        spin_lock_irqsave(&ace->lock, flags);
+        ace->users++;
+        spin_unlock_irqrestore(&ace->lock, flags);
+
+        check_disk_change(inode->i_bdev);
+        return 0;
+}
+
+static int ace_release(struct inode *inode, struct file *filp)
+{
+        struct ace_device *ace = inode->i_bdev->bd_disk->private_data;
+        unsigned long flags;
+        u16 val;
+
+        dev_dbg(ace->dev, "ace_release() users=%i\n", ace->users - 1);
+
+        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);
+        return 0;
+}
+
+static int ace_ioctl(struct inode *inode, struct file *filp,
+                     unsigned int cmd, unsigned long arg)
+{
+        struct ace_device *ace = inode->i_bdev->bd_disk->private_data;
+        struct hd_geometry __user *geo = (struct hd_geometry __user *)arg;
+        struct hd_geometry g;
+        dev_dbg(ace->dev, "ace_ioctl()\n");
+
+        switch (cmd) {
+        case HDIO_GETGEO:
+                g.heads = ace->cf_id.heads;
+                g.sectors = ace->cf_id.sectors;
+                g.cylinders = ace->cf_id.cyls;
+                g.start = 0;
+                return copy_to_user(geo, &g, sizeof(g)) ? -EFAULT : 0;
+
+        default:
+                return -ENOTTY;
+        }
+        return -ENOTTY;
+}
+
+static struct block_device_operations ace_fops = {
+        .owner = THIS_MODULE,
+        .open = ace_open,
+        .release = ace_release,
+        .media_changed = ace_media_changed,
+        .revalidate_disk = ace_revalidate_disk,
+        .ioctl = ace_ioctl,
+};
+
+/* --------------------------------------------------------------------
+ * SystemACE device setup/teardown code
+ */
+static int __devinit ace_setup(struct ace_device *ace)
+{
+        u16 version;
+        u16 val;
+
+        int rc;
+
+        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;
+
+        if (ace->irq != NO_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\n");
+                        ace->irq = NO_IRQ;
+                }
+        }
+
+        /*
+         * 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_hardsect_size(ace->queue, 512);
+
+        /*
+         * 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 == 1) {
+                /* 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);
+
+        /* 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\n",
+                 (version >> 12) & 0xf, (version >> 8) & 0x0f, version & 0xff);
+        dev_dbg(ace->dev, "physaddr 0x%lx, mapped to 0x%p, irq=%i\n",
+                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);
+        if (ace->irq != NO_IRQ)
+                free_irq(ace->irq, ace);
+      err_ioremap:
+        printk(KERN_INFO "xsysace: error initializing device at 0x%lx\n",
+               ace->physaddr);
+        return -ENOMEM;
+}
+
+static void __devexit 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 != NO_IRQ)
+                free_irq(ace->irq, ace);
+
+        iounmap(ace->baseaddr);
+}
+
+/* ---------------------------------------------------------------------
+ * Platform Bus Support
+ */
+
+static int __devinit ace_probe(struct device *device)
+{
+        struct platform_device *dev = to_platform_device(device);
+        struct ace_device *ace;
+        int i;
+
+        dev_dbg(device, "ace_probe(%p)\n", device);
+
+        /*
+         * Allocate the ace device structure
+         */
+        ace = kzalloc(sizeof(struct ace_device), GFP_KERNEL);
+        if (!ace)
+                goto err_alloc;
+
+        ace->dev = device;
+        ace->id = dev->id;
+        ace->irq = NO_IRQ;
+
+        for (i = 0; i < dev->num_resources; i++) {
+                if (dev->resource[i].flags & IORESOURCE_MEM)
+                        ace->physaddr = dev->resource[i].start;
+                if (dev->resource[i].flags & IORESOURCE_IRQ)
+                        ace->irq = dev->resource[i].start;
+        }
+
+        /* FIXME: Should get bus_width from the platform_device struct */
+        ace->bus_width = 1;
+
+        dev_set_drvdata(&dev->dev, ace);
+
+        /* Call the bus-independant setup code */
+        if (ace_setup(ace) != 0)
+                goto err_setup;
+
+        return 0;
+
+      err_setup:
+        dev_set_drvdata(&dev->dev, NULL);
+        kfree(ace);
+      err_alloc:
+        printk(KERN_ERR "xsysace: could not initialize device\n");
+        return -ENOMEM;
+}
+
+/*
+ * Platform bus remove() method
+ */
+static int __devexit ace_remove(struct device *device)
+{
+        struct ace_device *ace = dev_get_drvdata(device);
+
+        dev_dbg(device, "ace_remove(%p)\n", device);
+
+        if (ace) {
+                ace_teardown(ace);
+                kfree(ace);
+        }
+
+        return 0;
+}
+
+static struct device_driver ace_driver = {
+        .name = "xsysace",
+        .bus = &platform_bus_type,
+        .probe = ace_probe,
+        .remove = __devexit_p(ace_remove),
+};
+
+/* ---------------------------------------------------------------------
+ * Module init/exit routines
+ */
+static int __init ace_init(void)
+{
+        ace_major = register_blkdev(ace_major, "xsysace");
+        if (ace_major <= 0) {
+                printk(KERN_WARNING "xsysace: register_blkdev() failed\n");
+                return ace_major;
+        }
+
+        pr_debug("Registering Xilinx SystemACE driver, major=%i\n", ace_major);
+        return driver_register(&ace_driver);
+}
+
+static void __exit ace_exit(void)
+{
+        pr_debug("Unregistering Xilinx SystemACE driver\n");
+        driver_unregister(&ace_driver);
+        if (unregister_blkdev(ace_major, "xsysace"))
+                printk(KERN_WARNING "systemace unregister_blkdev(%i) failed\n",
+                       ace_major);
+}
+
+module_init(ace_init);
+module_exit(ace_exit);