// SPDX-License-Identifier: GPL-2.0
/*
 * system.c - a driver for reserving pnp system resources
 *
 * Some code is based on pnpbios_core.c
 * Copyright 2002 Adam Belay <ambx1@neo.rr.com>
 * (c) Copyright 2007 Hewlett-Packard Development Company, L.P.
 *      Bjorn Helgaas <bjorn.helgaas@hp.com>
 */

#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);
}

/*
 * Reserve motherboard resources after PCI claim BARs,
 * but before PCI assign resources for uninitialized PCI devices
 */
fs_initcall(pnp_system_init);