// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Fake VME bridge support.
 *
 * This drive provides a fake VME bridge chip, this enables debugging of the
 * VME framework in the absence of a VME system.
 *
 * This driver has to do a number of things in software that would be driven
 * by hardware if it was available, it will also result in extra overhead at
 * times when compared with driving actual hardware.
 *
 * Author: Martyn Welch <martyn@welches.me.uk>
 * Copyright (c) 2014 Martyn Welch
 *
 * Based on vme_tsi148.c:
 *
 * Author: Martyn Welch <martyn.welch@ge.com>
 * Copyright 2008 GE Intelligent Platforms Embedded Systems, Inc.
 *
 * Based on work by Tom Armistead and Ajit Prem
 * Copyright 2004 Motorola Inc.
 */

#include <linux/device.h>
#include <linux/errno.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/types.h>

#include "vme.h"
#include "vme_bridge.h"

/*
 *  Define the number of each that the fake driver supports.
 */
#define FAKE_MAX_MASTER         8       /* Max Master Windows */
#define FAKE_MAX_SLAVE          8       /* Max Slave Windows */

/* Structures to hold information normally held in device registers */
struct fake_slave_window {
        int enabled;
        unsigned long long vme_base;
        unsigned long long size;
        void *buf_base;
        u32 aspace;
        u32 cycle;
};

struct fake_master_window {
        int enabled;
        unsigned long long vme_base;
        unsigned long long size;
        u32 aspace;
        u32 cycle;
        u32 dwidth;
};

/* Structure used to hold driver specific information */
struct fake_driver {
        struct vme_bridge *parent;
        struct fake_slave_window slaves[FAKE_MAX_SLAVE];
        struct fake_master_window masters[FAKE_MAX_MASTER];
        u32 lm_enabled;
        unsigned long long lm_base;
        u32 lm_aspace;
        u32 lm_cycle;
        void (*lm_callback[4])(void *);
        void *lm_data[4];
        struct tasklet_struct int_tasklet;
        int int_level;
        int int_statid;
        void *crcsr_kernel;
        dma_addr_t crcsr_bus;
        /* Only one VME interrupt can be generated at a time, provide locking */
        struct mutex vme_int;
};

/* Module parameter */
static u32 geoid;

static const char driver_name[] = "vme_fake";

static struct vme_bridge *exit_pointer;

static struct device *vme_root;

/*
 * Calling VME bus interrupt callback if provided.
 */
static void fake_VIRQ_tasklet(unsigned long data)
{
        struct vme_bridge *fake_bridge;
        struct fake_driver *bridge;

        fake_bridge = (struct vme_bridge *)data;
        bridge = fake_bridge->driver_priv;

        vme_irq_handler(fake_bridge, bridge->int_level, bridge->int_statid);
}

/*
 * Configure VME interrupt
 */
static void fake_irq_set(struct vme_bridge *fake_bridge, int level,
                         int state, int sync)
{
        /* Nothing to do */
}

static void *fake_pci_to_ptr(dma_addr_t addr)
{
        return (void *)(uintptr_t)addr;
}

static dma_addr_t fake_ptr_to_pci(void *addr)
{
        return (dma_addr_t)(uintptr_t)addr;
}

/*
 * Generate a VME bus interrupt at the requested level & vector. Wait for
 * interrupt to be acked.
 */
static int fake_irq_generate(struct vme_bridge *fake_bridge, int level,
                             int statid)
{
        struct fake_driver *bridge;

        bridge = fake_bridge->driver_priv;

        mutex_lock(&bridge->vme_int);

        bridge->int_level = level;

        bridge->int_statid = statid;

        /*
         * Schedule tasklet to run VME handler to emulate normal VME interrupt
         * handler behaviour.
         */
        tasklet_schedule(&bridge->int_tasklet);

        mutex_unlock(&bridge->vme_int);

        return 0;
}

/*
 * Initialize a slave window with the requested attributes.
 */
static int fake_slave_set(struct vme_slave_resource *image, int enabled,
                          unsigned long long vme_base, unsigned long long size,
                          dma_addr_t buf_base, u32 aspace, u32 cycle)
{
        unsigned int i, granularity = 0;
        unsigned long long vme_bound;
        struct vme_bridge *fake_bridge;
        struct fake_driver *bridge;

        fake_bridge = image->parent;
        bridge = fake_bridge->driver_priv;

        i = image->number;

        switch (aspace) {
        case VME_A16:
                granularity = 0x10;
                break;
        case VME_A24:
                granularity = 0x1000;
                break;
        case VME_A32:
                granularity = 0x10000;
                break;
        case VME_A64:
                granularity = 0x10000;
                break;
        case VME_CRCSR:
        case VME_USER1:
        case VME_USER2:
        case VME_USER3:
        case VME_USER4:
        default:
                pr_err("Invalid address space\n");
                return -EINVAL;
        }

        /*
         * Bound address is a valid address for the window, adjust
         * accordingly
         */
        vme_bound = vme_base + size - granularity;

        if (vme_base & (granularity - 1)) {
                pr_err("Invalid VME base alignment\n");
                return -EINVAL;
        }
        if (vme_bound & (granularity - 1)) {
                pr_err("Invalid VME bound alignment\n");
                return -EINVAL;
        }

        mutex_lock(&image->mtx);

        bridge->slaves[i].enabled = enabled;
        bridge->slaves[i].vme_base = vme_base;
        bridge->slaves[i].size = size;
        bridge->slaves[i].buf_base = fake_pci_to_ptr(buf_base);
        bridge->slaves[i].aspace = aspace;
        bridge->slaves[i].cycle = cycle;

        mutex_unlock(&image->mtx);

        return 0;
}

/*
 * Get slave window configuration.
 */
static int fake_slave_get(struct vme_slave_resource *image, int *enabled,
                          unsigned long long *vme_base, unsigned long long *size,
                          dma_addr_t *buf_base, u32 *aspace, u32 *cycle)
{
        unsigned int i;
        struct fake_driver *bridge;

        bridge = image->parent->driver_priv;

        i = image->number;

        mutex_lock(&image->mtx);

        *enabled = bridge->slaves[i].enabled;
        *vme_base = bridge->slaves[i].vme_base;
        *size = bridge->slaves[i].size;
        *buf_base = fake_ptr_to_pci(bridge->slaves[i].buf_base);
        *aspace = bridge->slaves[i].aspace;
        *cycle = bridge->slaves[i].cycle;

        mutex_unlock(&image->mtx);

        return 0;
}

/*
 * Set the attributes of an outbound window.
 */
static int fake_master_set(struct vme_master_resource *image, int enabled,
                           unsigned long long vme_base, unsigned long long size,
                           u32 aspace, u32 cycle, u32 dwidth)
{
        int retval = 0;
        unsigned int i;
        struct vme_bridge *fake_bridge;
        struct fake_driver *bridge;

        fake_bridge = image->parent;

        bridge = fake_bridge->driver_priv;

        /* Verify input data */
        if (vme_base & 0xFFFF) {
                pr_err("Invalid VME Window alignment\n");
                retval = -EINVAL;
                goto err_window;
        }

        if (size & 0xFFFF) {
                pr_err("Invalid size alignment\n");
                retval = -EINVAL;
                goto err_window;
        }

        if ((size == 0) && (enabled != 0)) {
                pr_err("Size must be non-zero for enabled windows\n");
                retval = -EINVAL;
                goto err_window;
        }

        /* Setup data width */
        switch (dwidth) {
        case VME_D8:
        case VME_D16:
        case VME_D32:
                break;
        default:
                pr_err("Invalid data width\n");
                retval = -EINVAL;
                goto err_dwidth;
        }

        /* Setup address space */
        switch (aspace) {
        case VME_A16:
        case VME_A24:
        case VME_A32:
        case VME_A64:
        case VME_CRCSR:
        case VME_USER1:
        case VME_USER2:
        case VME_USER3:
        case VME_USER4:
                break;
        default:
                pr_err("Invalid address space\n");
                retval = -EINVAL;
                goto err_aspace;
        }

        spin_lock(&image->lock);

        i = image->number;

        bridge->masters[i].enabled = enabled;
        bridge->masters[i].vme_base = vme_base;
        bridge->masters[i].size = size;
        bridge->masters[i].aspace = aspace;
        bridge->masters[i].cycle = cycle;
        bridge->masters[i].dwidth = dwidth;

        spin_unlock(&image->lock);

        return 0;

err_aspace:
err_dwidth:
err_window:
        return retval;
}

/*
 * Set the attributes of an outbound window.
 */
static int __fake_master_get(struct vme_master_resource *image, int *enabled,
                             unsigned long long *vme_base, unsigned long long *size,
                             u32 *aspace, u32 *cycle, u32 *dwidth)
{
        unsigned int i;
        struct fake_driver *bridge;

        bridge = image->parent->driver_priv;

        i = image->number;

        *enabled = bridge->masters[i].enabled;
        *vme_base = bridge->masters[i].vme_base;
        *size = bridge->masters[i].size;
        *aspace = bridge->masters[i].aspace;
        *cycle = bridge->masters[i].cycle;
        *dwidth = bridge->masters[i].dwidth;

        return 0;
}

static int fake_master_get(struct vme_master_resource *image, int *enabled,
                           unsigned long long *vme_base, unsigned long long *size,
                           u32 *aspace, u32 *cycle, u32 *dwidth)
{
        int retval;

        spin_lock(&image->lock);

        retval = __fake_master_get(image, enabled, vme_base, size, aspace,
                                   cycle, dwidth);

        spin_unlock(&image->lock);

        return retval;
}

static void fake_lm_check(struct fake_driver *bridge, unsigned long long addr,
                          u32 aspace, u32 cycle)
{
        struct vme_bridge *fake_bridge;
        unsigned long long lm_base;
        u32 lm_aspace, lm_cycle;
        int i;
        struct vme_lm_resource *lm;
        struct list_head *pos = NULL, *n;

        /* Get vme_bridge */
        fake_bridge = bridge->parent;

        /* Loop through each location monitor resource */
        list_for_each_safe(pos, n, &fake_bridge->lm_resources) {
                lm = list_entry(pos, struct vme_lm_resource, list);

                /* If disabled, we're done */
                if (bridge->lm_enabled == 0)
                        return;

                lm_base = bridge->lm_base;
                lm_aspace = bridge->lm_aspace;
                lm_cycle = bridge->lm_cycle;

                /* First make sure that the cycle and address space match */
                if ((lm_aspace == aspace) && (lm_cycle == cycle)) {
                        for (i = 0; i < lm->monitors; i++) {
                                /* Each location monitor covers 8 bytes */
                                if (((lm_base + (8 * i)) <= addr) &&
                                    ((lm_base + (8 * i) + 8) > addr)) {
                                        if (bridge->lm_callback[i])
                                                bridge->lm_callback[i](bridge->lm_data[i]);
                                }
                        }
                }
        }
}

static noinline_for_stack u8 fake_vmeread8(struct fake_driver *bridge,
                                           unsigned long long addr,
                                           u32 aspace, u32 cycle)
{
        u8 retval = 0xff;
        int i;
        unsigned long long start, end, offset;
        u8 *loc;

        for (i = 0; i < FAKE_MAX_SLAVE; i++) {
                start = bridge->slaves[i].vme_base;
                end = bridge->slaves[i].vme_base + bridge->slaves[i].size;

                if (aspace != bridge->slaves[i].aspace)
                        continue;

                if (cycle != bridge->slaves[i].cycle)
                        continue;

                if ((addr >= start) && (addr < end)) {
                        offset = addr - bridge->slaves[i].vme_base;
                        loc = (u8 *)(bridge->slaves[i].buf_base + offset);
                        retval = *loc;

                        break;
                }
        }

        fake_lm_check(bridge, addr, aspace, cycle);

        return retval;
}

static noinline_for_stack u16 fake_vmeread16(struct fake_driver *bridge,
                                             unsigned long long addr,
                                             u32 aspace, u32 cycle)
{
        u16 retval = 0xffff;
        int i;
        unsigned long long start, end, offset;
        u16 *loc;

        for (i = 0; i < FAKE_MAX_SLAVE; i++) {
                if (aspace != bridge->slaves[i].aspace)
                        continue;

                if (cycle != bridge->slaves[i].cycle)
                        continue;

                start = bridge->slaves[i].vme_base;
                end = bridge->slaves[i].vme_base + bridge->slaves[i].size;

                if ((addr >= start) && ((addr + 1) < end)) {
                        offset = addr - bridge->slaves[i].vme_base;
                        loc = (u16 *)(bridge->slaves[i].buf_base + offset);
                        retval = *loc;

                        break;
                }
        }

        fake_lm_check(bridge, addr, aspace, cycle);

        return retval;
}

static noinline_for_stack u32 fake_vmeread32(struct fake_driver *bridge,
                                             unsigned long long addr,
                                             u32 aspace, u32 cycle)
{
        u32 retval = 0xffffffff;
        int i;
        unsigned long long start, end, offset;
        u32 *loc;

        for (i = 0; i < FAKE_MAX_SLAVE; i++) {
                if (aspace != bridge->slaves[i].aspace)
                        continue;

                if (cycle != bridge->slaves[i].cycle)
                        continue;

                start = bridge->slaves[i].vme_base;
                end = bridge->slaves[i].vme_base + bridge->slaves[i].size;

                if ((addr >= start) && ((addr + 3) < end)) {
                        offset = addr - bridge->slaves[i].vme_base;
                        loc = (u32 *)(bridge->slaves[i].buf_base + offset);
                        retval = *loc;

                        break;
                }
        }

        fake_lm_check(bridge, addr, aspace, cycle);

        return retval;
}

static ssize_t fake_master_read(struct vme_master_resource *image, void *buf,
                                size_t count, loff_t offset)
{
        int retval;
        u32 aspace, cycle, dwidth;
        struct vme_bridge *fake_bridge;
        struct fake_driver *priv;
        int i;
        unsigned long long addr;
        unsigned int done = 0;
        unsigned int count32;

        fake_bridge = image->parent;

        priv = fake_bridge->driver_priv;

        i = image->number;

        addr = (unsigned long long)priv->masters[i].vme_base + offset;
        aspace = priv->masters[i].aspace;
        cycle = priv->masters[i].cycle;
        dwidth = priv->masters[i].dwidth;

        spin_lock(&image->lock);

        /* The following code handles VME address alignment. We cannot use
         * memcpy_xxx here because it may cut data transfers in to 8-bit
         * cycles when D16 or D32 cycles are required on the VME bus.
         * On the other hand, the bridge itself assures that the maximum data
         * cycle configured for the transfer is used and splits it
         * automatically for non-aligned addresses, so we don't want the
         * overhead of needlessly forcing small transfers for the entire cycle.
         */
        if (addr & 0x1) {
                *(u8 *)buf = fake_vmeread8(priv, addr, aspace, cycle);
                done += 1;
                if (done == count)
                        goto out;
        }
        if ((dwidth == VME_D16) || (dwidth == VME_D32)) {
                if ((addr + done) & 0x2) {
                        if ((count - done) < 2) {
                                *(u8 *)(buf + done) = fake_vmeread8(priv,
                                                addr + done, aspace, cycle);
                                done += 1;
                                goto out;
                        } else {
                                *(u16 *)(buf + done) = fake_vmeread16(priv,
                                                addr + done, aspace, cycle);
                                done += 2;
                        }
                }
        }

        if (dwidth == VME_D32) {
                count32 = (count - done) & ~0x3;
                while (done < count32) {
                        *(u32 *)(buf + done) = fake_vmeread32(priv, addr + done,
                                        aspace, cycle);
                        done += 4;
                }
        } else if (dwidth == VME_D16) {
                count32 = (count - done) & ~0x3;
                while (done < count32) {
                        *(u16 *)(buf + done) = fake_vmeread16(priv, addr + done,
                                        aspace, cycle);
                        done += 2;
                }
        } else if (dwidth == VME_D8) {
                count32 = (count - done);
                while (done < count32) {
                        *(u8 *)(buf + done) = fake_vmeread8(priv, addr + done,
                                        aspace, cycle);
                        done += 1;
                }
        }

        if ((dwidth == VME_D16) || (dwidth == VME_D32)) {
                if ((count - done) & 0x2) {
                        *(u16 *)(buf + done) = fake_vmeread16(priv, addr + done,
                                        aspace, cycle);
                        done += 2;
                }
        }
        if ((count - done) & 0x1) {
                *(u8 *)(buf + done) = fake_vmeread8(priv, addr + done, aspace,
                                cycle);
                done += 1;
        }

out:
        retval = count;

        spin_unlock(&image->lock);

        return retval;
}

static noinline_for_stack void fake_vmewrite8(struct fake_driver *bridge,
                                              u8 *buf, unsigned long long addr,
                                              u32 aspace, u32 cycle)
{
        int i;
        unsigned long long start, end, offset;
        u8 *loc;

        for (i = 0; i < FAKE_MAX_SLAVE; i++) {
                if (aspace != bridge->slaves[i].aspace)
                        continue;

                if (cycle != bridge->slaves[i].cycle)
                        continue;

                start = bridge->slaves[i].vme_base;
                end = bridge->slaves[i].vme_base + bridge->slaves[i].size;

                if ((addr >= start) && (addr < end)) {
                        offset = addr - bridge->slaves[i].vme_base;
                        loc = (u8 *)((void *)bridge->slaves[i].buf_base + offset);
                        *loc = *buf;

                        break;
                }
        }

        fake_lm_check(bridge, addr, aspace, cycle);
}

static noinline_for_stack void fake_vmewrite16(struct fake_driver *bridge,
                                               u16 *buf, unsigned long long addr,
                                               u32 aspace, u32 cycle)
{
        int i;
        unsigned long long start, end, offset;
        u16 *loc;

        for (i = 0; i < FAKE_MAX_SLAVE; i++) {
                if (aspace != bridge->slaves[i].aspace)
                        continue;

                if (cycle != bridge->slaves[i].cycle)
                        continue;

                start = bridge->slaves[i].vme_base;
                end = bridge->slaves[i].vme_base + bridge->slaves[i].size;

                if ((addr >= start) && ((addr + 1) < end)) {
                        offset = addr - bridge->slaves[i].vme_base;
                        loc = (u16 *)((void *)bridge->slaves[i].buf_base + offset);
                        *loc = *buf;

                        break;
                }
        }

        fake_lm_check(bridge, addr, aspace, cycle);
}

static noinline_for_stack void fake_vmewrite32(struct fake_driver *bridge,
                                               u32 *buf, unsigned long long addr,
                                               u32 aspace, u32 cycle)
{
        int i;
        unsigned long long start, end, offset;
        u32 *loc;

        for (i = 0; i < FAKE_MAX_SLAVE; i++) {
                if (aspace != bridge->slaves[i].aspace)
                        continue;

                if (cycle != bridge->slaves[i].cycle)
                        continue;

                start = bridge->slaves[i].vme_base;
                end = bridge->slaves[i].vme_base + bridge->slaves[i].size;

                if ((addr >= start) && ((addr + 3) < end)) {
                        offset = addr - bridge->slaves[i].vme_base;
                        loc = (u32 *)((void *)bridge->slaves[i].buf_base + offset);
                        *loc = *buf;

                        break;
                }
        }

        fake_lm_check(bridge, addr, aspace, cycle);
}

static ssize_t fake_master_write(struct vme_master_resource *image, void *buf,
                                 size_t count, loff_t offset)
{
        int retval = 0;
        u32 aspace, cycle, dwidth;
        unsigned long long addr;
        int i;
        unsigned int done = 0;
        unsigned int count32;

        struct vme_bridge *fake_bridge;
        struct fake_driver *bridge;

        fake_bridge = image->parent;

        bridge = fake_bridge->driver_priv;

        i = image->number;

        addr = bridge->masters[i].vme_base + offset;
        aspace = bridge->masters[i].aspace;
        cycle = bridge->masters[i].cycle;
        dwidth = bridge->masters[i].dwidth;

        spin_lock(&image->lock);

        /* Here we apply for the same strategy we do in master_read
         * function in order to assure the correct cycles.
         */
        if (addr & 0x1) {
                fake_vmewrite8(bridge, (u8 *)buf, addr, aspace, cycle);
                done += 1;
                if (done == count)
                        goto out;
        }

        if ((dwidth == VME_D16) || (dwidth == VME_D32)) {
                if ((addr + done) & 0x2) {
                        if ((count - done) < 2) {
                                fake_vmewrite8(bridge, (u8 *)(buf + done),
                                               addr + done, aspace, cycle);
                                done += 1;
                                goto out;
                        } else {
                                fake_vmewrite16(bridge, (u16 *)(buf + done),
                                                addr + done, aspace, cycle);
                                done += 2;
                        }
                }
        }

        if (dwidth == VME_D32) {
                count32 = (count - done) & ~0x3;
                while (done < count32) {
                        fake_vmewrite32(bridge, (u32 *)(buf + done),
                                        addr + done, aspace, cycle);
                        done += 4;
                }
        } else if (dwidth == VME_D16) {
                count32 = (count - done) & ~0x3;
                while (done < count32) {
                        fake_vmewrite16(bridge, (u16 *)(buf + done),
                                        addr + done, aspace, cycle);
                        done += 2;
                }
        } else if (dwidth == VME_D8) {
                count32 = (count - done);
                while (done < count32) {
                        fake_vmewrite8(bridge, (u8 *)(buf + done), addr + done,
                                       aspace, cycle);
                        done += 1;
                }
        }

        if ((dwidth == VME_D16) || (dwidth == VME_D32)) {
                if ((count - done) & 0x2) {
                        fake_vmewrite16(bridge, (u16 *)(buf + done),
                                        addr + done, aspace, cycle);
                        done += 2;
                }
        }

        if ((count - done) & 0x1) {
                fake_vmewrite8(bridge, (u8 *)(buf + done), addr + done, aspace,
                               cycle);
                done += 1;
        }

out:
        retval = count;

        spin_unlock(&image->lock);

        return retval;
}

/*
 * Perform an RMW cycle on the VME bus.
 *
 * Requires a previously configured master window, returns final value.
 */
static unsigned int fake_master_rmw(struct vme_master_resource *image,
                                    unsigned int mask, unsigned int compare,
                                    unsigned int swap, loff_t offset)
{
        u32 tmp, base;
        u32 aspace, cycle;
        int i;
        struct fake_driver *bridge;

        bridge = image->parent->driver_priv;

        /* Find the PCI address that maps to the desired VME address */
        i = image->number;

        base = bridge->masters[i].vme_base;
        aspace = bridge->masters[i].aspace;
        cycle = bridge->masters[i].cycle;

        /* Lock image */
        spin_lock(&image->lock);

        /* Read existing value */
        tmp = fake_vmeread32(bridge, base + offset, aspace, cycle);

        /* Perform check */
        if ((tmp && mask) == (compare && mask)) {
                tmp = tmp | (mask | swap);
                tmp = tmp & (~mask | swap);

                /* Write back */
                fake_vmewrite32(bridge, &tmp, base + offset, aspace, cycle);
        }

        /* Unlock image */
        spin_unlock(&image->lock);

        return tmp;
}

/*
 * All 4 location monitors reside at the same base - this is therefore a
 * system wide configuration.
 *
 * This does not enable the LM monitor - that should be done when the first
 * callback is attached and disabled when the last callback is removed.
 */
static int fake_lm_set(struct vme_lm_resource *lm, unsigned long long lm_base,
                       u32 aspace, u32 cycle)
{
        int i;
        struct vme_bridge *fake_bridge;
        struct fake_driver *bridge;

        fake_bridge = lm->parent;

        bridge = fake_bridge->driver_priv;

        mutex_lock(&lm->mtx);

        /* If we already have a callback attached, we can't move it! */
        for (i = 0; i < lm->monitors; i++) {
                if (bridge->lm_callback[i]) {
                        mutex_unlock(&lm->mtx);
                        pr_err("Location monitor callback attached, can't reset\n");
                        return -EBUSY;
                }
        }

        switch (aspace) {
        case VME_A16:
        case VME_A24:
        case VME_A32:
        case VME_A64:
                break;
        default:
                mutex_unlock(&lm->mtx);
                pr_err("Invalid address space\n");
                return -EINVAL;
        }

        bridge->lm_base = lm_base;
        bridge->lm_aspace = aspace;
        bridge->lm_cycle = cycle;

        mutex_unlock(&lm->mtx);

        return 0;
}

/* Get configuration of the callback monitor and return whether it is enabled
 * or disabled.
 */
static int fake_lm_get(struct vme_lm_resource *lm,
                       unsigned long long *lm_base,
                       u32 *aspace, u32 *cycle)
{
        struct fake_driver *bridge;

        bridge = lm->parent->driver_priv;

        mutex_lock(&lm->mtx);

        *lm_base = bridge->lm_base;
        *aspace = bridge->lm_aspace;
        *cycle = bridge->lm_cycle;

        mutex_unlock(&lm->mtx);

        return bridge->lm_enabled;
}

/*
 * Attach a callback to a specific location monitor.
 *
 * Callback will be passed the monitor triggered.
 */
static int fake_lm_attach(struct vme_lm_resource *lm, int monitor,
                          void (*callback)(void *), void *data)
{
        struct vme_bridge *fake_bridge;
        struct fake_driver *bridge;

        fake_bridge = lm->parent;

        bridge = fake_bridge->driver_priv;

        mutex_lock(&lm->mtx);

        /* Ensure that the location monitor is configured - need PGM or DATA */
        if (bridge->lm_cycle == 0) {
                mutex_unlock(&lm->mtx);
                pr_err("Location monitor not properly configured\n");
                return -EINVAL;
        }

        /* Check that a callback isn't already attached */
        if (bridge->lm_callback[monitor]) {
                mutex_unlock(&lm->mtx);
                pr_err("Existing callback attached\n");
                return -EBUSY;
        }

        /* Attach callback */
        bridge->lm_callback[monitor] = callback;
        bridge->lm_data[monitor] = data;

        /* Ensure that global Location Monitor Enable set */
        bridge->lm_enabled = 1;

        mutex_unlock(&lm->mtx);

        return 0;
}

/*
 * Detach a callback function forn a specific location monitor.
 */
static int fake_lm_detach(struct vme_lm_resource *lm, int monitor)
{
        u32 tmp;
        int i;
        struct fake_driver *bridge;

        bridge = lm->parent->driver_priv;

        mutex_lock(&lm->mtx);

        /* Detach callback */
        bridge->lm_callback[monitor] = NULL;
        bridge->lm_data[monitor] = NULL;

        /* If all location monitors disabled, disable global Location Monitor */
        tmp = 0;
        for (i = 0; i < lm->monitors; i++) {
                if (bridge->lm_callback[i])
                        tmp = 1;
        }

        if (tmp == 0)
                bridge->lm_enabled = 0;

        mutex_unlock(&lm->mtx);

        return 0;
}

/*
 * Determine Geographical Addressing
 */
static int fake_slot_get(struct vme_bridge *fake_bridge)
{
        return geoid;
}

static void *fake_alloc_consistent(struct device *parent, size_t size,
                                   dma_addr_t *dma)
{
        void *alloc = kmalloc(size, GFP_KERNEL);

        if (alloc)
                *dma = fake_ptr_to_pci(alloc);

        return alloc;
}

static void fake_free_consistent(struct device *parent, size_t size,
                                 void *vaddr, dma_addr_t dma)
{
        kfree(vaddr);
}

/*
 * Configure CR/CSR space
 *
 * Access to the CR/CSR can be configured at power-up. The location of the
 * CR/CSR registers in the CR/CSR address space is determined by the boards
 * Geographic address.
 *
 * Each board has a 512kB window, with the highest 4kB being used for the
 * boards registers, this means there is a fix length 508kB window which must
 * be mapped onto PCI memory.
 */
static int fake_crcsr_init(struct vme_bridge *fake_bridge)
{
        u32 vstat;
        struct fake_driver *bridge;

        bridge = fake_bridge->driver_priv;

        /* Allocate mem for CR/CSR image */
        bridge->crcsr_kernel = kzalloc(VME_CRCSR_BUF_SIZE, GFP_KERNEL);
        bridge->crcsr_bus = fake_ptr_to_pci(bridge->crcsr_kernel);
        if (!bridge->crcsr_kernel)
                return -ENOMEM;

        vstat = fake_slot_get(fake_bridge);

        pr_info("CR/CSR Offset: %d\n", vstat);

        return 0;
}

static void fake_crcsr_exit(struct vme_bridge *fake_bridge)
{
        struct fake_driver *bridge;

        bridge = fake_bridge->driver_priv;

        kfree(bridge->crcsr_kernel);
}

static int __init fake_init(void)
{
        int retval, i;
        struct list_head *pos = NULL, *n;
        struct vme_bridge *fake_bridge;
        struct fake_driver *fake_device;
        struct vme_master_resource *master_image;
        struct vme_slave_resource *slave_image;
        struct vme_lm_resource *lm;

        if (geoid >= VME_MAX_SLOTS) {
                pr_err("VME geographical address must be between 0 and %d (exclusive), but got %d\n",
                       VME_MAX_SLOTS, geoid);
                return -EINVAL;
        }

        /* We need a fake parent device */
        vme_root = root_device_register("vme");
        if (IS_ERR(vme_root))
                return PTR_ERR(vme_root);

        /* If we want to support more than one bridge at some point, we need to
         * dynamically allocate this so we get one per device.
         */
        fake_bridge = kzalloc_obj(*fake_bridge);
        if (!fake_bridge) {
                retval = -ENOMEM;
                goto err_struct;
        }

        fake_device = kzalloc_obj(*fake_device);
        if (!fake_device) {
                retval = -ENOMEM;
                goto err_driver;
        }

        fake_bridge->driver_priv = fake_device;

        fake_bridge->parent = vme_root;

        fake_device->parent = fake_bridge;

        /* Initialize wait queues & mutual exclusion flags */
        mutex_init(&fake_device->vme_int);
        mutex_init(&fake_bridge->irq_mtx);
        tasklet_init(&fake_device->int_tasklet, fake_VIRQ_tasklet,
                     (unsigned long)fake_bridge);

        strscpy(fake_bridge->name, driver_name, sizeof(fake_bridge->name));

        /* Add master windows to list */
        INIT_LIST_HEAD(&fake_bridge->master_resources);
        for (i = 0; i < FAKE_MAX_MASTER; i++) {
                master_image = kmalloc_obj(*master_image);
                if (!master_image) {
                        retval = -ENOMEM;
                        goto err_master;
                }
                master_image->parent = fake_bridge;
                spin_lock_init(&master_image->lock);
                master_image->locked = 0;
                master_image->number = i;
                master_image->address_attr = VME_A16 | VME_A24 | VME_A32 |
                        VME_A64;
                master_image->cycle_attr = VME_SCT | VME_BLT | VME_MBLT |
                        VME_2eVME | VME_2eSST | VME_2eSSTB | VME_2eSST160 |
                        VME_2eSST267 | VME_2eSST320 | VME_SUPER | VME_USER |
                        VME_PROG | VME_DATA;
                master_image->width_attr = VME_D16 | VME_D32;
                memset(&master_image->bus_resource, 0,
                       sizeof(struct resource));
                master_image->kern_base  = NULL;
                list_add_tail(&master_image->list,
                              &fake_bridge->master_resources);
        }

        /* Add slave windows to list */
        INIT_LIST_HEAD(&fake_bridge->slave_resources);
        for (i = 0; i < FAKE_MAX_SLAVE; i++) {
                slave_image = kmalloc_obj(*slave_image);
                if (!slave_image) {
                        retval = -ENOMEM;
                        goto err_slave;
                }
                slave_image->parent = fake_bridge;
                mutex_init(&slave_image->mtx);
                slave_image->locked = 0;
                slave_image->number = i;
                slave_image->address_attr = VME_A16 | VME_A24 | VME_A32 |
                        VME_A64 | VME_CRCSR | VME_USER1 | VME_USER2 |
                        VME_USER3 | VME_USER4;
                slave_image->cycle_attr = VME_SCT | VME_BLT | VME_MBLT |
                        VME_2eVME | VME_2eSST | VME_2eSSTB | VME_2eSST160 |
                        VME_2eSST267 | VME_2eSST320 | VME_SUPER | VME_USER |
                        VME_PROG | VME_DATA;
                list_add_tail(&slave_image->list,
                              &fake_bridge->slave_resources);
        }

        /* Add location monitor to list */
        INIT_LIST_HEAD(&fake_bridge->lm_resources);
        lm = kmalloc_obj(*lm);
        if (!lm) {
                retval = -ENOMEM;
                goto err_lm;
        }
        lm->parent = fake_bridge;
        mutex_init(&lm->mtx);
        lm->locked = 0;
        lm->number = 1;
        lm->monitors = 4;
        list_add_tail(&lm->list, &fake_bridge->lm_resources);

        fake_bridge->slave_get = fake_slave_get;
        fake_bridge->slave_set = fake_slave_set;
        fake_bridge->master_get = fake_master_get;
        fake_bridge->master_set = fake_master_set;
        fake_bridge->master_read = fake_master_read;
        fake_bridge->master_write = fake_master_write;
        fake_bridge->master_rmw = fake_master_rmw;
        fake_bridge->irq_set = fake_irq_set;
        fake_bridge->irq_generate = fake_irq_generate;
        fake_bridge->lm_set = fake_lm_set;
        fake_bridge->lm_get = fake_lm_get;
        fake_bridge->lm_attach = fake_lm_attach;
        fake_bridge->lm_detach = fake_lm_detach;
        fake_bridge->slot_get = fake_slot_get;
        fake_bridge->alloc_consistent = fake_alloc_consistent;
        fake_bridge->free_consistent = fake_free_consistent;

        pr_info("Board is%s the VME system controller\n",
                (geoid == 1) ? "" : " not");

        pr_info("VME geographical address is set to %d\n", geoid);

        retval = fake_crcsr_init(fake_bridge);
        if (retval) {
                pr_err("CR/CSR configuration failed.\n");
                goto err_crcsr;
        }

        retval = vme_register_bridge(fake_bridge);
        if (retval != 0) {
                pr_err("Chip Registration failed.\n");
                goto err_reg;
        }

        exit_pointer = fake_bridge;

        return 0;

err_reg:
        fake_crcsr_exit(fake_bridge);
err_crcsr:
err_lm:
        /* resources are stored in link list */
        list_for_each_safe(pos, n, &fake_bridge->lm_resources) {
                lm = list_entry(pos, struct vme_lm_resource, list);
                list_del(pos);
                kfree(lm);
        }
err_slave:
        /* resources are stored in link list */
        list_for_each_safe(pos, n, &fake_bridge->slave_resources) {
                slave_image = list_entry(pos, struct vme_slave_resource, list);
                list_del(pos);
                kfree(slave_image);
        }
err_master:
        /* resources are stored in link list */
        list_for_each_safe(pos, n, &fake_bridge->master_resources) {
                master_image = list_entry(pos, struct vme_master_resource,
                                          list);
                list_del(pos);
                kfree(master_image);
        }

        kfree(fake_device);
err_driver:
        kfree(fake_bridge);
err_struct:
        return retval;
}

static void __exit fake_exit(void)
{
        struct list_head *pos = NULL;
        struct list_head *tmplist;
        struct vme_master_resource *master_image;
        struct vme_slave_resource *slave_image;
        int i;
        struct vme_bridge *fake_bridge;
        struct fake_driver *bridge;

        fake_bridge = exit_pointer;

        bridge = fake_bridge->driver_priv;

        pr_debug("Driver is being unloaded.\n");

        /*
         *  Shutdown all inbound and outbound windows.
         */
        for (i = 0; i < FAKE_MAX_MASTER; i++)
                bridge->masters[i].enabled = 0;

        for (i = 0; i < FAKE_MAX_SLAVE; i++)
                bridge->slaves[i].enabled = 0;

        /*
         *  Shutdown Location monitor.
         */
        bridge->lm_enabled = 0;

        vme_unregister_bridge(fake_bridge);

        fake_crcsr_exit(fake_bridge);
        /* resources are stored in link list */
        list_for_each_safe(pos, tmplist, &fake_bridge->slave_resources) {
                slave_image = list_entry(pos, struct vme_slave_resource, list);
                list_del(pos);
                kfree(slave_image);
        }

        /* resources are stored in link list */
        list_for_each_safe(pos, tmplist, &fake_bridge->master_resources) {
                master_image = list_entry(pos, struct vme_master_resource,
                                          list);
                list_del(pos);
                kfree(master_image);
        }

        kfree(fake_bridge->driver_priv);

        kfree(fake_bridge);

        root_device_unregister(vme_root);
}

MODULE_PARM_DESC(geoid, "Set geographical addressing");
module_param(geoid, uint, 0);

MODULE_DESCRIPTION("Fake VME bridge driver");
MODULE_LICENSE("GPL");

module_init(fake_init);
module_exit(fake_exit);