uio_pdrv.c

Go to the documentation of this file.

/*
 * drivers/uio/uio_pdrv.c
 *
 * Copyright (C) 2008 by Digi International Inc.
 * All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 as published by
 * the Free Software Foundation.
 */
#include <linux/platform_device.h>
#include <linux/uio_driver.h>
#include <linux/stringify.h>
#include <linux/module.h>
#include <linux/slab.h>

#define DRIVER_NAME "uio_pdrv"

struct uio_platdata {
    struct uio_info *uioinfo;
};

static int uio_pdrv_probe(struct platform_device *pdev)
{
    struct uio_info *uioinfo = pdev->dev.platform_data;
    struct uio_platdata *pdata;
    struct uio_mem *uiomem;
    int ret = -ENODEV;
    int i;

    if (!uioinfo || !uioinfo->name || !uioinfo->version) {
        dev_dbg(&pdev->dev, "%s: err_uioinfo\n", __func__);
        goto err_uioinfo;
    }

    pdata = kzalloc(sizeof(*pdata), GFP_KERNEL);
    if (!pdata) {
        ret = -ENOMEM;
        dev_dbg(&pdev->dev, "%s: err_alloc_pdata\n", __func__);
        goto err_alloc_pdata;
    }

    pdata->uioinfo = uioinfo;

    uiomem = &uioinfo->mem[0];

    for (i = 0; i < pdev->num_resources; ++i) {
        struct resource *r = &pdev->resource[i];

        if (r->flags != IORESOURCE_MEM)
            continue;

        if (uiomem >= &uioinfo->mem[MAX_UIO_MAPS]) {
            dev_warn(&pdev->dev, "device has more than "
                    __stringify(MAX_UIO_MAPS)
                    " I/O memory resources.\n");
            break;
        }

        uiomem->memtype = UIO_MEM_PHYS;
        uiomem->addr = r->start;
        uiomem->size = resource_size(r);
        ++uiomem;
    }

    while (uiomem < &uioinfo->mem[MAX_UIO_MAPS]) {
        uiomem->size = 0;
        ++uiomem;
    }

    pdata->uioinfo->priv = pdata;

    ret = uio_register_device(&pdev->dev, pdata->uioinfo);

    if (ret) {
        kfree(pdata);
err_alloc_pdata:
err_uioinfo:
        return ret;
    }

    platform_set_drvdata(pdev, pdata);

    return 0;
}

static int uio_pdrv_remove(struct platform_device *pdev)
{
    struct uio_platdata *pdata = platform_get_drvdata(pdev);

    uio_unregister_device(pdata->uioinfo);

    kfree(pdata);

    return 0;
}

static struct platform_driver uio_pdrv = {
    .probe = uio_pdrv_probe,
    .remove = uio_pdrv_remove,
    .driver = {
        .name = DRIVER_NAME,
        .owner = THIS_MODULE,
    },
};

module_platform_driver(uio_pdrv);

MODULE_AUTHOR("Uwe Kleine-Koenig");
MODULE_DESCRIPTION("Userspace I/O platform driver");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:" DRIVER_NAME);