/*
 * IBM PowerPC IBM eBus Infrastructure Support.
 *
 * Copyright (c) 2005 IBM Corporation
 *  Joachim Fenkes <fenkes@de.ibm.com>
 *  Heiko J Schick <schickhj@de.ibm.com>
 *
 * All rights reserved.
 *
 * This source code is distributed under a dual license of GPL v2.0 and OpenIB
 * BSD.
 *
 * OpenIB BSD License
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * Redistributions of source code must retain the above copyright notice, this
 * list of conditions and the following disclaimer.
 *
 * Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials
 * provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
 * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
 * IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include <linux/init.h>
#include <linux/export.h>
#include <linux/console.h>
#include <linux/kobject.h>
#include <linux/dma-map-ops.h>
#include <linux/interrupt.h>
#include <linux/irqdomain.h>
#include <linux/of.h>
#include <linux/slab.h>
#include <linux/stat.h>
#include <linux/of_platform.h>
#include <linux/platform_device.h>
#include <asm/ibmebus.h>
#include <asm/machdep.h>

static struct device ibmebus_bus_device = { /* fake "parent" device */
        .init_name = "ibmebus",
};

const struct bus_type ibmebus_bus_type;

/* These devices will automatically be added to the bus during init */
static const struct of_device_id ibmebus_matches[] __initconst = {
        { .compatible = "IBM,lhca" },
        { .compatible = "IBM,lhea" },
        {},
};

static void *ibmebus_alloc_coherent(struct device *dev,
                                    size_t size,
                                    dma_addr_t *dma_handle,
                                    gfp_t flag,
                                    unsigned long attrs)
{
        void *mem;

        mem = kmalloc(size, flag);
        *dma_handle = (dma_addr_t)mem;

        return mem;
}

static void ibmebus_free_coherent(struct device *dev,
                                  size_t size, void *vaddr,
                                  dma_addr_t dma_handle,
                                  unsigned long attrs)
{
        kfree(vaddr);
}

static dma_addr_t ibmebus_map_phys(struct device *dev, phys_addr_t phys,
                                   size_t size,
                                   enum dma_data_direction direction,
                                   unsigned long attrs)
{
        if (attrs & DMA_ATTR_MMIO)
                return DMA_MAPPING_ERROR;

        return (dma_addr_t)(phys_to_virt(phys));
}

static void ibmebus_unmap_phys(struct device *dev,
                               dma_addr_t dma_addr,
                               size_t size,
                               enum dma_data_direction direction,
                               unsigned long attrs)
{
        return;
}

static int ibmebus_map_sg(struct device *dev,
                          struct scatterlist *sgl,
                          int nents, enum dma_data_direction direction,
                          unsigned long attrs)
{
        struct scatterlist *sg;
        int i;

        for_each_sg(sgl, sg, nents, i) {
                sg->dma_address = (dma_addr_t) sg_virt(sg);
                sg->dma_length = sg->length;
        }

        return nents;
}

static void ibmebus_unmap_sg(struct device *dev,
                             struct scatterlist *sg,
                             int nents, enum dma_data_direction direction,
                             unsigned long attrs)
{
        return;
}

static int ibmebus_dma_supported(struct device *dev, u64 mask)
{
        return mask == DMA_BIT_MASK(64);
}

static u64 ibmebus_dma_get_required_mask(struct device *dev)
{
        return DMA_BIT_MASK(64);
}

static const struct dma_map_ops ibmebus_dma_ops = {
        .alloc              = ibmebus_alloc_coherent,
        .free               = ibmebus_free_coherent,
        .map_sg             = ibmebus_map_sg,
        .unmap_sg           = ibmebus_unmap_sg,
        .dma_supported      = ibmebus_dma_supported,
        .get_required_mask  = ibmebus_dma_get_required_mask,
        .map_phys           = ibmebus_map_phys,
        .unmap_phys         = ibmebus_unmap_phys,
};

static int ibmebus_match_path(struct device *dev, const void *data)
{
        struct device_node *dn = to_platform_device(dev)->dev.of_node;
        struct device_node *tn = of_find_node_by_path(data);

        of_node_put(tn);

        return (tn == dn);
}

static int ibmebus_match_node(struct device *dev, const void *data)
{
        return to_platform_device(dev)->dev.of_node == data;
}

static int ibmebus_create_device(struct device_node *dn)
{
        struct platform_device *dev;
        int ret;

        dev = of_device_alloc(dn, NULL, &ibmebus_bus_device);
        if (!dev)
                return -ENOMEM;

        dev->dev.bus = &ibmebus_bus_type;
        dev->dev.dma_ops = &ibmebus_dma_ops;

        ret = of_device_add(dev);
        if (ret)
                platform_device_put(dev);
        return ret;
}

static int ibmebus_create_devices(const struct of_device_id *matches)
{
        struct device_node *root, *child;
        struct device *dev;
        int ret = 0;

        root = of_find_node_by_path("/");

        for_each_child_of_node(root, child) {
                if (!of_match_node(matches, child))
                        continue;

                dev = bus_find_device(&ibmebus_bus_type, NULL, child,
                                      ibmebus_match_node);
                if (dev) {
                        put_device(dev);
                        continue;
                }

                ret = ibmebus_create_device(child);
                if (ret) {
                        printk(KERN_ERR "%s: failed to create device (%i)",
                               __func__, ret);
                        of_node_put(child);
                        break;
                }
        }

        of_node_put(root);
        return ret;
}

int ibmebus_register_driver(struct platform_driver *drv)
{
        /* If the driver uses devices that ibmebus doesn't know, add them */
        ibmebus_create_devices(drv->driver.of_match_table);

        drv->driver.bus = &ibmebus_bus_type;
        return driver_register(&drv->driver);
}
EXPORT_SYMBOL(ibmebus_register_driver);

void ibmebus_unregister_driver(struct platform_driver *drv)
{
        driver_unregister(&drv->driver);
}
EXPORT_SYMBOL(ibmebus_unregister_driver);

int ibmebus_request_irq(u32 ist, irq_handler_t handler,
                        unsigned long irq_flags, const char *devname,
                        void *dev_id)
{
        unsigned int irq = irq_create_mapping(NULL, ist);

        if (!irq)
                return -EINVAL;

        return request_irq(irq, handler, irq_flags, devname, dev_id);
}
EXPORT_SYMBOL(ibmebus_request_irq);

void ibmebus_free_irq(u32 ist, void *dev_id)
{
        unsigned int irq = irq_find_mapping(NULL, ist);

        free_irq(irq, dev_id);
        irq_dispose_mapping(irq);
}
EXPORT_SYMBOL(ibmebus_free_irq);

static char *ibmebus_chomp(const char *in, size_t count)
{
        char *out = kmalloc(count + 1, GFP_KERNEL);

        if (!out)
                return NULL;

        memcpy(out, in, count);
        out[count] = '\0';
        if (out[count - 1] == '\n')
                out[count - 1] = '\0';

        return out;
}

static ssize_t probe_store(const struct bus_type *bus, const char *buf, size_t count)
{
        struct device_node *dn = NULL;
        struct device *dev;
        char *path;
        ssize_t rc = 0;

        path = ibmebus_chomp(buf, count);
        if (!path)
                return -ENOMEM;

        dev = bus_find_device(&ibmebus_bus_type, NULL, path,
                              ibmebus_match_path);
        if (dev) {
                put_device(dev);
                printk(KERN_WARNING "%s: %s has already been probed\n",
                       __func__, path);
                rc = -EEXIST;
                goto out;
        }

        if ((dn = of_find_node_by_path(path))) {
                rc = ibmebus_create_device(dn);
                of_node_put(dn);
        } else {
                printk(KERN_WARNING "%s: no such device node: %s\n",
                       __func__, path);
                rc = -ENODEV;
        }

out:
        kfree(path);
        if (rc)
                return rc;
        return count;
}
static BUS_ATTR_WO(probe);

static ssize_t remove_store(const struct bus_type *bus, const char *buf, size_t count)
{
        struct device *dev;
        char *path;

        path = ibmebus_chomp(buf, count);
        if (!path)
                return -ENOMEM;

        if ((dev = bus_find_device(&ibmebus_bus_type, NULL, path,
                                   ibmebus_match_path))) {
                of_device_unregister(to_platform_device(dev));
                put_device(dev);

                kfree(path);
                return count;
        } else {
                printk(KERN_WARNING "%s: %s not on the bus\n",
                       __func__, path);

                kfree(path);
                return -ENODEV;
        }
}
static BUS_ATTR_WO(remove);

static struct attribute *ibmbus_bus_attrs[] = {
        &bus_attr_probe.attr,
        &bus_attr_remove.attr,
        NULL,
};
ATTRIBUTE_GROUPS(ibmbus_bus);

static int ibmebus_bus_bus_match(struct device *dev, const struct device_driver *drv)
{
        const struct of_device_id *matches = drv->of_match_table;

        if (!matches)
                return 0;

        return of_match_device(matches, dev) != NULL;
}

static int ibmebus_bus_device_probe(struct device *dev)
{
        int error = -ENODEV;
        struct platform_driver *drv;
        struct platform_device *of_dev;

        drv = to_platform_driver(dev->driver);
        of_dev = to_platform_device(dev);

        if (!drv->probe)
                return error;

        get_device(dev);

        if (of_driver_match_device(dev, dev->driver))
                error = drv->probe(of_dev);
        if (error)
                put_device(dev);

        return error;
}

static void ibmebus_bus_device_remove(struct device *dev)
{
        struct platform_device *of_dev = to_platform_device(dev);
        struct platform_driver *drv = to_platform_driver(dev->driver);

        if (dev->driver && drv->remove)
                drv->remove(of_dev);
}

static void ibmebus_bus_device_shutdown(struct device *dev)
{
        struct platform_device *of_dev = to_platform_device(dev);
        struct platform_driver *drv = to_platform_driver(dev->driver);

        if (dev->driver && drv->shutdown)
                drv->shutdown(of_dev);
}

/*
 * ibmebus_bus_device_attrs
 */
static ssize_t devspec_show(struct device *dev,
                                struct device_attribute *attr, char *buf)
{
        struct platform_device *ofdev;

        ofdev = to_platform_device(dev);
        return sprintf(buf, "%pOF\n", ofdev->dev.of_node);
}
static DEVICE_ATTR_RO(devspec);

static ssize_t name_show(struct device *dev,
                                struct device_attribute *attr, char *buf)
{
        struct platform_device *ofdev;

        ofdev = to_platform_device(dev);
        return sprintf(buf, "%pOFn\n", ofdev->dev.of_node);
}
static DEVICE_ATTR_RO(name);

static ssize_t modalias_show(struct device *dev,
                                struct device_attribute *attr, char *buf)
{
        return of_device_modalias(dev, buf, PAGE_SIZE);
}
static DEVICE_ATTR_RO(modalias);

static struct attribute *ibmebus_bus_device_attrs[] = {
        &dev_attr_devspec.attr,
        &dev_attr_name.attr,
        &dev_attr_modalias.attr,
        NULL,
};
ATTRIBUTE_GROUPS(ibmebus_bus_device);

static int ibmebus_bus_modalias(const struct device *dev, struct kobj_uevent_env *env)
{
        return of_device_uevent_modalias(dev, env);
}

const struct bus_type ibmebus_bus_type = {
        .name      = "ibmebus",
        .uevent    = ibmebus_bus_modalias,
        .bus_groups = ibmbus_bus_groups,
        .match     = ibmebus_bus_bus_match,
        .probe     = ibmebus_bus_device_probe,
        .remove    = ibmebus_bus_device_remove,
        .shutdown  = ibmebus_bus_device_shutdown,
        .dev_groups = ibmebus_bus_device_groups,
};
EXPORT_SYMBOL(ibmebus_bus_type);

static int __init ibmebus_bus_init(void)
{
        int err;

        printk(KERN_INFO "IBM eBus Device Driver\n");

        err = bus_register(&ibmebus_bus_type);
        if (err) {
                printk(KERN_ERR "%s: failed to register IBM eBus.\n",
                       __func__);
                return err;
        }

        err = device_register(&ibmebus_bus_device);
        if (err) {
                printk(KERN_WARNING "%s: device_register returned %i\n",
                       __func__, err);
                put_device(&ibmebus_bus_device);
                bus_unregister(&ibmebus_bus_type);

                return err;
        }

        err = ibmebus_create_devices(ibmebus_matches);
        if (err) {
                device_unregister(&ibmebus_bus_device);
                bus_unregister(&ibmebus_bus_type);
                return err;
        }

        return 0;
}
machine_postcore_initcall(pseries, ibmebus_bus_init);