system.c

Go to the documentation of this file.

/*
 * system.c - a driver for reserving pnp system resources
 *
 * Some code is based on pnpbios_core.c
 * Copyright 2002 Adam Belay <[email protected]>
 * (c) Copyright 2007 Hewlett-Packard Development Company, L.P.
 *  Bjorn Helgaas <[email protected]>
 */

#include <linux/pnp.h>
#include <linux/device.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/kernel.h>
#include <linux/ioport.h>

static const struct pnp_device_id pnp_dev_table[] = {
    /* General ID for reserving resources */
    {"PNP0c02", 0},
    /* memory controller */
    {"PNP0c01", 0},
    {"", 0}
};

static void reserve_range(struct pnp_dev *dev, struct resource *r, int port)
{
    char *regionid;
    const char *pnpid = dev_name(&dev->dev);
    resource_size_t start = r->start, end = r->end;
    struct resource *res;

    regionid = kmalloc(16, GFP_KERNEL);
    if (!regionid)
        return;

    snprintf(regionid, 16, "pnp %s", pnpid);
    if (port)
        res = request_region(start, end - start + 1, regionid);
    else
        res = request_mem_region(start, end - start + 1, regionid);
    if (res)
        res->flags &= ~IORESOURCE_BUSY;
    else
        kfree(regionid);

    /*
     * Failures at this point are usually harmless. pci quirks for
     * example do reserve stuff they know about too, so we may well
     * have double reservations.
     */
    dev_info(&dev->dev, "%pR %s reserved\n", r,
         res ? "has been" : "could not be");
}

static void reserve_resources_of_dev(struct pnp_dev *dev)
{
    struct resource *res;
    int i;

    for (i = 0; (res = pnp_get_resource(dev, IORESOURCE_IO, i)); i++) {
        if (res->flags & IORESOURCE_DISABLED)
            continue;
        if (res->start == 0)
            continue;   /* disabled */
        if (res->start < 0x100)
            /*
             * Below 0x100 is only standard PC hardware
             * (pics, kbd, timer, dma, ...)
             * We should not get resource conflicts there,
             * and the kernel reserves these anyway
             * (see arch/i386/kernel/setup.c).
             * So, do nothing
             */
            continue;
        if (res->end < res->start)
            continue;   /* invalid */

        reserve_range(dev, res, 1);
    }

    for (i = 0; (res = pnp_get_resource(dev, IORESOURCE_MEM, i)); i++) {
        if (res->flags & IORESOURCE_DISABLED)
            continue;

        reserve_range(dev, res, 0);
    }
}

static int system_pnp_probe(struct pnp_dev *dev,
                const struct pnp_device_id *dev_id)
{
    reserve_resources_of_dev(dev);
    return 0;
}

static struct pnp_driver system_pnp_driver = {
    .name     = "system",
    .id_table = pnp_dev_table,
    .flags    = PNP_DRIVER_RES_DO_NOT_CHANGE,
    .probe    = system_pnp_probe,
};

static int __init pnp_system_init(void)
{
    return pnp_register_driver(&system_pnp_driver);
}

fs_initcall(pnp_system_init);