umc-bus.c

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/*
 * 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/module.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;
}

int umc_controller_reset(struct umc_dev *umc)
{
    struct device *parent = umc->dev.parent;
    int ret = 0;

    if (device_trylock(parent))
        return -EAGAIN;
    ret = device_for_each_child(parent, parent, umc_bus_pre_reset_helper);
    if (ret >= 0)
        ret = device_for_each_child(parent, parent, umc_bus_post_reset_helper);
    device_unlock(parent);

    return ret;
}
EXPORT_SYMBOL_GPL(umc_controller_reset);

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");