// SPDX-License-Identifier: GPL-2.0
/*
 * ISA bus.
 */

#include <linux/device.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/dma-mapping.h>
#include <linux/isa.h>

static struct device isa_bus = {
        .init_name      = "isa"
};

struct isa_dev {
        struct device dev;
        struct device *next;
        unsigned int id;
};

#define to_isa_dev(x) container_of((x), struct isa_dev, dev)

static int isa_bus_match(struct device *dev, const struct device_driver *driver)
{
        struct isa_driver *isa_driver = to_isa_driver(driver);

        if (dev->platform_data == isa_driver) {
                if (!isa_driver->match ||
                        isa_driver->match(dev, to_isa_dev(dev)->id))
                        return 1;
                dev->platform_data = NULL;
        }
        return 0;
}

static int isa_bus_probe(struct device *dev)
{
        struct isa_driver *isa_driver = dev->platform_data;

        if (isa_driver && isa_driver->probe)
                return isa_driver->probe(dev, to_isa_dev(dev)->id);

        return 0;
}

static void isa_bus_remove(struct device *dev)
{
        struct isa_driver *isa_driver = dev->platform_data;

        if (isa_driver && isa_driver->remove)
                isa_driver->remove(dev, to_isa_dev(dev)->id);
}

static void isa_bus_shutdown(struct device *dev)
{
        struct isa_driver *isa_driver = dev->platform_data;

        if (isa_driver && isa_driver->shutdown)
                isa_driver->shutdown(dev, to_isa_dev(dev)->id);
}

static int isa_bus_suspend(struct device *dev, pm_message_t state)
{
        struct isa_driver *isa_driver = dev->platform_data;

        if (isa_driver && isa_driver->suspend)
                return isa_driver->suspend(dev, to_isa_dev(dev)->id, state);

        return 0;
}

static int isa_bus_resume(struct device *dev)
{
        struct isa_driver *isa_driver = dev->platform_data;

        if (isa_driver && isa_driver->resume)
                return isa_driver->resume(dev, to_isa_dev(dev)->id);

        return 0;
}

static const struct bus_type isa_bus_type = {
        .name           = "isa",
        .match          = isa_bus_match,
        .probe          = isa_bus_probe,
        .remove         = isa_bus_remove,
        .shutdown       = isa_bus_shutdown,
        .suspend        = isa_bus_suspend,
        .resume         = isa_bus_resume
};

static void isa_dev_release(struct device *dev)
{
        kfree(to_isa_dev(dev));
}

void isa_unregister_driver(struct isa_driver *isa_driver)
{
        struct device *dev = isa_driver->devices;

        while (dev) {
                struct device *tmp = to_isa_dev(dev)->next;
                device_unregister(dev);
                dev = tmp;
        }
        driver_unregister(&isa_driver->driver);
}
EXPORT_SYMBOL_GPL(isa_unregister_driver);

int isa_register_driver(struct isa_driver *isa_driver, unsigned int ndev)
{
        int error;
        unsigned int id;

        isa_driver->driver.bus  = &isa_bus_type;
        isa_driver->devices     = NULL;

        error = driver_register(&isa_driver->driver);
        if (error)
                return error;

        for (id = 0; id < ndev; id++) {
                struct isa_dev *isa_dev;

                isa_dev = kzalloc_obj(*isa_dev);
                if (!isa_dev) {
                        error = -ENOMEM;
                        break;
                }

                isa_dev->dev.parent     = &isa_bus;
                isa_dev->dev.bus        = &isa_bus_type;

                dev_set_name(&isa_dev->dev, "%s.%u",
                             isa_driver->driver.name, id);
                isa_dev->dev.platform_data      = isa_driver;
                isa_dev->dev.release            = isa_dev_release;
                isa_dev->id                     = id;

                isa_dev->dev.coherent_dma_mask = DMA_BIT_MASK(24);
                isa_dev->dev.dma_mask = &isa_dev->dev.coherent_dma_mask;

                error = device_register(&isa_dev->dev);
                if (error) {
                        put_device(&isa_dev->dev);
                        break;
                }

                isa_dev->next = isa_driver->devices;
                isa_driver->devices = &isa_dev->dev;
        }

        if (!error && !isa_driver->devices)
                error = -ENODEV;

        if (error)
                isa_unregister_driver(isa_driver);

        return error;
}
EXPORT_SYMBOL_GPL(isa_register_driver);

static int __init isa_bus_init(void)
{
        int error;

        error = bus_register(&isa_bus_type);
        if (!error) {
                error = device_register(&isa_bus);
                if (error)
                        bus_unregister(&isa_bus_type);
        }
        return error;
}

postcore_initcall(isa_bus_init);