/*
 * Bus for UWB Multi-interface Controller capabilities.
 *
 * Copyright (C) 2007 Cambridge Silicon Radio Ltd.
 *
 * This file is released under the GNU GPL v2.
 */
#include <linux/kernel.h>
#include <linux/sysfs.h>
#include <linux/workqueue.h>
#include <linux/uwb/umc.h>
#include <linux/pci.h>

static int umc_bus_pre_reset_helper(struct device *dev, void *data)
{
        int ret = 0;

        if (dev->driver) {
                struct umc_dev *umc = to_umc_dev(dev);
                struct umc_driver *umc_drv = to_umc_driver(dev->driver);

                if (umc_drv->pre_reset)
                        ret = umc_drv->pre_reset(umc);
                else
                        device_release_driver(dev);
        }
        return ret;
}

static int umc_bus_post_reset_helper(struct device *dev, void *data)
{
        int ret = 0;

        if (dev->driver) {
                struct umc_dev *umc = to_umc_dev(dev);
                struct umc_driver *umc_drv = to_umc_driver(dev->driver);

                if (umc_drv->post_reset)
                        ret = umc_drv->post_reset(umc);
        } else
                ret = device_attach(dev);

        return ret;
}

/**
 * umc_controller_reset - reset the whole UMC controller
 * @umc: the UMC device for the radio controller.
 *
 * Drivers or all capabilities of the controller will have their
 * pre_reset methods called or be unbound from their device.  Then all
 * post_reset methods will be called or the drivers will be rebound.
 *
 * Radio controllers must provide pre_reset and post_reset methods and
 * reset the hardware in their start method.
 *
 * If this is called while a probe() or remove() is in progress it
 * will return -EAGAIN and not perform the reset.
 */
int umc_controller_reset(struct umc_dev *umc)
{
        struct device *parent = umc->dev.parent;
        int ret = 0;

        if(down_trylock(&parent->sem))
                return -EAGAIN;
        ret = device_for_each_child(parent, parent, umc_bus_pre_reset_helper);
        if (ret >= 0)
                device_for_each_child(parent, parent, umc_bus_post_reset_helper);
        up(&parent->sem);

        return ret;
}
EXPORT_SYMBOL_GPL(umc_controller_reset);

/**
 * umc_match_pci_id - match a UMC driver to a UMC device's parent PCI device.
 * @umc_drv: umc driver with match_data pointing to a zero-terminated
 * table of pci_device_id's.
 * @umc: umc device whose parent is to be matched.
 */
int umc_match_pci_id(struct umc_driver *umc_drv, struct umc_dev *umc)
{
        const struct pci_device_id *id_table = umc_drv->match_data;
        struct pci_dev *pci;

        if (umc->dev.parent->bus != &pci_bus_type)
                return 0;

        pci = to_pci_dev(umc->dev.parent);
        return pci_match_id(id_table, pci) != NULL;
}
EXPORT_SYMBOL_GPL(umc_match_pci_id);

static int umc_bus_rescan_helper(struct device *dev, void *data)
{
        int ret = 0;

        if (!dev->driver)
                ret = device_attach(dev);

        return ret;
}

static void umc_bus_rescan(struct device *parent)
{
        int err;

        /*
         * We can't use bus_rescan_devices() here as it deadlocks when
         * it tries to retake the dev->parent semaphore.
         */
        err = device_for_each_child(parent, NULL, umc_bus_rescan_helper);
        if (err < 0)
                printk(KERN_WARNING "%s: rescan of bus failed: %d\n",
                       KBUILD_MODNAME, err);
}

static int umc_bus_match(struct device *dev, struct device_driver *drv)
{
        struct umc_dev *umc = to_umc_dev(dev);
        struct umc_driver *umc_driver = to_umc_driver(drv);

        if (umc->cap_id == umc_driver->cap_id) {
                if (umc_driver->match)
                        return umc_driver->match(umc_driver, umc);
                else
                        return 1;
        }
        return 0;
}

static int umc_device_probe(struct device *dev)
{
        struct umc_dev *umc;
        struct umc_driver *umc_driver;
        int err;

        umc_driver = to_umc_driver(dev->driver);
        umc = to_umc_dev(dev);

        get_device(dev);
        err = umc_driver->probe(umc);
        if (err)
                put_device(dev);
        else
                umc_bus_rescan(dev->parent);

        return err;
}

static int umc_device_remove(struct device *dev)
{
        struct umc_dev *umc;
        struct umc_driver *umc_driver;

        umc_driver = to_umc_driver(dev->driver);
        umc = to_umc_dev(dev);

        umc_driver->remove(umc);
        put_device(dev);
        return 0;
}

static int umc_device_suspend(struct device *dev, pm_message_t state)
{
        struct umc_dev *umc;
        struct umc_driver *umc_driver;
        int err = 0;

        umc = to_umc_dev(dev);

        if (dev->driver) {
                umc_driver = to_umc_driver(dev->driver);
                if (umc_driver->suspend)
                        err = umc_driver->suspend(umc, state);
        }
        return err;
}

static int umc_device_resume(struct device *dev)
{
        struct umc_dev *umc;
        struct umc_driver *umc_driver;
        int err = 0;

        umc = to_umc_dev(dev);

        if (dev->driver) {
                umc_driver = to_umc_driver(dev->driver);
                if (umc_driver->resume)
                        err = umc_driver->resume(umc);
        }
        return err;
}

static ssize_t capability_id_show(struct device *dev, struct device_attribute *attr, char *buf)
{
        struct umc_dev *umc = to_umc_dev(dev);

        return sprintf(buf, "0x%02x\n", umc->cap_id);
}

static ssize_t version_show(struct device *dev, struct device_attribute *attr, char *buf)
{
        struct umc_dev *umc = to_umc_dev(dev);

        return sprintf(buf, "0x%04x\n", umc->version);
}

static struct device_attribute umc_dev_attrs[] = {
        __ATTR_RO(capability_id),
        __ATTR_RO(version),
        __ATTR_NULL,
};

struct bus_type umc_bus_type = {
        .name           = "umc",
        .match          = umc_bus_match,
        .probe          = umc_device_probe,
        .remove         = umc_device_remove,
        .suspend        = umc_device_suspend,
        .resume         = umc_device_resume,
        .dev_attrs      = umc_dev_attrs,
};
EXPORT_SYMBOL_GPL(umc_bus_type);

static int __init umc_bus_init(void)
{
        return bus_register(&umc_bus_type);
}
module_init(umc_bus_init);

static void __exit umc_bus_exit(void)
{
        bus_unregister(&umc_bus_type);
}
module_exit(umc_bus_exit);

MODULE_DESCRIPTION("UWB Multi-interface Controller capability bus");
MODULE_AUTHOR("Cambridge Silicon Radio Ltd.");
MODULE_LICENSE("GPL");