// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * pnpbios -- PnP BIOS driver
 *
 * This driver provides access to Plug-'n'-Play services provided by
 * the PnP BIOS firmware, described in the following documents:
 *   Plug and Play BIOS Specification, Version 1.0A, 5 May 1994
 *   Plug and Play BIOS Clarification Paper, 6 October 1994
 *     Compaq Computer Corporation, Phoenix Technologies Ltd., Intel Corp.
 * 
 * Originally (C) 1998 Christian Schmidt <schmidt@digadd.de>
 * Modifications (C) 1998 Tom Lees <tom@lpsg.demon.co.uk>
 * Minor reorganizations by David Hinds <dahinds@users.sourceforge.net>
 * Further modifications (C) 2001, 2002 by:
 *   Alan Cox <alan@redhat.com>
 *   Thomas Hood
 *   Brian Gerst <bgerst@didntduck.org>
 *
 * Ported to the PnP Layer and several additional improvements (C) 2002
 * by Adam Belay <ambx1@neo.rr.com>
 */

/* Change Log
 *
 * Adam Belay - <ambx1@neo.rr.com> - March 16, 2003
 * rev 1.01     Only call pnp_bios_dev_node_info once
 *              Added pnpbios_print_status
 *              Added several new error messages and info messages
 *              Added pnpbios_interface_attach_device
 *              integrated core and proc init system
 *              Introduced PNPMODE flags
 *              Removed some useless includes
 */

#include <linux/types.h>
#include <linux/init.h>
#include <linux/linkage.h>
#include <linux/kernel.h>
#include <linux/device.h>
#include <linux/pnp.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/slab.h>
#include <linux/completion.h>
#include <linux/spinlock.h>
#include <linux/dmi.h>
#include <linux/delay.h>
#include <linux/acpi.h>
#include <linux/freezer.h>
#include <linux/kmod.h>
#include <linux/kthread.h>

#include <asm/page.h>
#include <asm/desc.h>
#include <asm/byteorder.h>

#include "../base.h"
#include "pnpbios.h"

/*
 *
 * PnP BIOS INTERFACE
 *
 */

static union pnp_bios_install_struct *pnp_bios_install = NULL;

int pnp_bios_present(void)
{
        return (pnp_bios_install != NULL);
}

struct pnp_dev_node_info node_info;

/*
 *
 * DOCKING FUNCTIONS
 *
 */

static struct completion unload_sem;

/*
 * (Much of this belongs in a shared routine somewhere)
 */
static int pnp_dock_event(int dock, struct pnp_docking_station_info *info)
{
        static char const sbin_pnpbios[] = "/sbin/pnpbios";
        char *argv[3], **envp, *buf, *scratch;
        int i = 0, value;

        if (!(envp = kcalloc(20, sizeof(char *), GFP_KERNEL)))
                return -ENOMEM;
        if (!(buf = kzalloc(256, GFP_KERNEL))) {
                kfree(envp);
                return -ENOMEM;
        }

        /* FIXME: if there are actual users of this, it should be
         * integrated into the driver core and use the usual infrastructure
         * like sysfs and uevents
         */
        argv[0] = (char *)sbin_pnpbios;
        argv[1] = "dock";
        argv[2] = NULL;

        /* minimal command environment */
        envp[i++] = "HOME=/";
        envp[i++] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin";

#ifdef  DEBUG
        /* hint that policy agent should enter no-stdout debug mode */
        envp[i++] = "DEBUG=kernel";
#endif
        /* extensible set of named bus-specific parameters,
         * supporting multiple driver selection algorithms.
         */
        scratch = buf;

        /* action:  add, remove */
        envp[i++] = scratch;
        scratch += sprintf(scratch, "ACTION=%s", dock ? "add" : "remove") + 1;

        /* Report the ident for the dock */
        envp[i++] = scratch;
        scratch += sprintf(scratch, "DOCK=%x/%x/%x",
                           info->location_id, info->serial, info->capabilities);
        envp[i] = NULL;

        value = call_usermodehelper(sbin_pnpbios, argv, envp, UMH_WAIT_EXEC);
        kfree(buf);
        kfree(envp);
        return 0;
}

/*
 * Poll the PnP docking at regular intervals
 */
static int pnp_dock_thread(void *unused)
{
        static struct pnp_docking_station_info now;
        int docked = -1, d = 0;

        set_freezable();
        while (1) {
                int status;

                /*
                 * Poll every 2 seconds
                 */
                msleep_interruptible(2000);

                if (try_to_freeze())
                        continue;

                status = pnp_bios_dock_station_info(&now);

                switch (status) {
                        /*
                         * No dock to manage
                         */
                case PNP_FUNCTION_NOT_SUPPORTED:
                        kthread_complete_and_exit(&unload_sem, 0);
                case PNP_SYSTEM_NOT_DOCKED:
                        d = 0;
                        break;
                case PNP_SUCCESS:
                        d = 1;
                        break;
                default:
                        pnpbios_print_status("pnp_dock_thread", status);
                        printk(KERN_WARNING "PnPBIOS: disabling dock monitoring.\n");
                        kthread_complete_and_exit(&unload_sem, 0);
                }
                if (d != docked) {
                        if (pnp_dock_event(d, &now) == 0) {
                                docked = d;
#if 0
                                printk(KERN_INFO
                                       "PnPBIOS: Docking station %stached\n",
                                       docked ? "at" : "de");
#endif
                        }
                }
        }
        kthread_complete_and_exit(&unload_sem, 0);
}

static int pnpbios_get_resources(struct pnp_dev *dev)
{
        u8 nodenum = dev->number;
        struct pnp_bios_node *node;

        if (!pnpbios_is_dynamic(dev))
                return -EPERM;

        pnp_dbg(&dev->dev, "get resources\n");
        node = kzalloc(node_info.max_node_size, GFP_KERNEL);
        if (!node)
                return -1;
        if (pnp_bios_get_dev_node(&nodenum, (char)PNPMODE_DYNAMIC, node)) {
                kfree(node);
                return -ENODEV;
        }
        pnpbios_read_resources_from_node(dev, node);
        dev->active = pnp_is_active(dev);
        kfree(node);
        return 0;
}

static int pnpbios_set_resources(struct pnp_dev *dev)
{
        u8 nodenum = dev->number;
        struct pnp_bios_node *node;
        int ret;

        if (!pnpbios_is_dynamic(dev))
                return -EPERM;

        pnp_dbg(&dev->dev, "set resources\n");
        node = kzalloc(node_info.max_node_size, GFP_KERNEL);
        if (!node)
                return -1;
        if (pnp_bios_get_dev_node(&nodenum, (char)PNPMODE_DYNAMIC, node)) {
                kfree(node);
                return -ENODEV;
        }
        if (pnpbios_write_resources_to_node(dev, node) < 0) {
                kfree(node);
                return -1;
        }
        ret = pnp_bios_set_dev_node(node->handle, (char)PNPMODE_DYNAMIC, node);
        kfree(node);
        if (ret > 0)
                ret = -1;
        return ret;
}

static void pnpbios_zero_data_stream(struct pnp_bios_node *node)
{
        unsigned char *p = (char *)node->data;
        unsigned char *end = (char *)(node->data + node->size);
        unsigned int len;
        int i;

        while ((char *)p < (char *)end) {
                if (p[0] & 0x80) {      /* large tag */
                        len = (p[2] << 8) | p[1];
                        p += 3;
                } else {
                        if (((p[0] >> 3) & 0x0f) == 0x0f)
                                return;
                        len = p[0] & 0x07;
                        p += 1;
                }
                for (i = 0; i < len; i++)
                        p[i] = 0;
                p += len;
        }
        printk(KERN_ERR
               "PnPBIOS: Resource structure did not contain an end tag.\n");
}

static int pnpbios_disable_resources(struct pnp_dev *dev)
{
        struct pnp_bios_node *node;
        u8 nodenum = dev->number;
        int ret;

        if (dev->flags & PNPBIOS_NO_DISABLE || !pnpbios_is_dynamic(dev))
                return -EPERM;

        node = kzalloc(node_info.max_node_size, GFP_KERNEL);
        if (!node)
                return -ENOMEM;

        if (pnp_bios_get_dev_node(&nodenum, (char)PNPMODE_DYNAMIC, node)) {
                kfree(node);
                return -ENODEV;
        }
        pnpbios_zero_data_stream(node);

        ret = pnp_bios_set_dev_node(dev->number, (char)PNPMODE_DYNAMIC, node);
        kfree(node);
        if (ret > 0)
                ret = -1;
        return ret;
}

/* PnP Layer support */

struct pnp_protocol pnpbios_protocol = {
        .name = "Plug and Play BIOS",
        .get = pnpbios_get_resources,
        .set = pnpbios_set_resources,
        .disable = pnpbios_disable_resources,
};

static int __init insert_device(struct pnp_bios_node *node)
{
        struct pnp_dev *dev;
        char id[8];
        int error;

        /* check if the device is already added */
        list_for_each_entry(dev, &pnpbios_protocol.devices, protocol_list) {
                if (dev->number == node->handle)
                        return -EEXIST;
        }

        pnp_eisa_id_to_string(node->eisa_id & PNP_EISA_ID_MASK, id);
        dev = pnp_alloc_dev(&pnpbios_protocol, node->handle, id);
        if (!dev)
                return -ENOMEM;

        pnpbios_parse_data_stream(dev, node);
        dev->active = pnp_is_active(dev);
        dev->flags = node->flags;
        if (!(dev->flags & PNPBIOS_NO_CONFIG))
                dev->capabilities |= PNP_CONFIGURABLE;
        if (!(dev->flags & PNPBIOS_NO_DISABLE) && pnpbios_is_dynamic(dev))
                dev->capabilities |= PNP_DISABLE;
        dev->capabilities |= PNP_READ;
        if (pnpbios_is_dynamic(dev))
                dev->capabilities |= PNP_WRITE;
        if (dev->flags & PNPBIOS_REMOVABLE)
                dev->capabilities |= PNP_REMOVABLE;

        /* clear out the damaged flags */
        if (!dev->active)
                pnp_init_resources(dev);

        error = pnp_add_device(dev);
        if (error) {
                put_device(&dev->dev);
                return error;
        }

        pnpbios_interface_attach_device(node);

        return 0;
}

static void __init build_devlist(void)
{
        u8 nodenum;
        unsigned int nodes_got = 0;
        unsigned int devs = 0;
        struct pnp_bios_node *node;

        node = kzalloc(node_info.max_node_size, GFP_KERNEL);
        if (!node)
                return;

        for (nodenum = 0; nodenum < 0xff;) {
                u8 thisnodenum = nodenum;
                /* eventually we will want to use PNPMODE_STATIC here but for now
                 * dynamic will help us catch buggy bioses to add to the blacklist.
                 */
                if (!pnpbios_dont_use_current_config) {
                        if (pnp_bios_get_dev_node
                            (&nodenum, (char)PNPMODE_DYNAMIC, node))
                                break;
                } else {
                        if (pnp_bios_get_dev_node
                            (&nodenum, (char)PNPMODE_STATIC, node))
                                break;
                }
                nodes_got++;
                if (insert_device(node) == 0)
                        devs++;
                if (nodenum <= thisnodenum) {
                        printk(KERN_ERR
                               "PnPBIOS: build_devlist: Node number 0x%x is out of sequence following node 0x%x. Aborting.\n",
                               (unsigned int)nodenum,
                               (unsigned int)thisnodenum);
                        break;
                }
        }
        kfree(node);

        printk(KERN_INFO
               "PnPBIOS: %i node%s reported by PnP BIOS; %i recorded by driver\n",
               nodes_got, nodes_got != 1 ? "s" : "", devs);
}

/*
 *
 * INIT AND EXIT
 *
 */

static int pnpbios_disabled;
int pnpbios_dont_use_current_config;

static int __init pnpbios_setup(char *str)
{
        int invert;

        while ((str != NULL) && (*str != '\0')) {
                if (strncmp(str, "off", 3) == 0)
                        pnpbios_disabled = 1;
                if (strncmp(str, "on", 2) == 0)
                        pnpbios_disabled = 0;
                invert = (strncmp(str, "no-", 3) == 0);
                if (invert)
                        str += 3;
                if (strncmp(str, "curr", 4) == 0)
                        pnpbios_dont_use_current_config = invert;
                str = strchr(str, ',');
                if (str != NULL)
                        str += strspn(str, ", \t");
        }

        return 1;
}

__setup("pnpbios=", pnpbios_setup);

/* PnP BIOS signature: "$PnP" */
#define PNP_SIGNATURE   (('$' << 0) + ('P' << 8) + ('n' << 16) + ('P' << 24))

static int __init pnpbios_probe_system(void)
{
        union pnp_bios_install_struct *check;
        u8 sum;
        int length, i;

        printk(KERN_INFO "PnPBIOS: Scanning system for PnP BIOS support...\n");

        /*
         * Search the defined area (0xf0000-0xffff0) for a valid PnP BIOS
         * structure and, if one is found, sets up the selectors and
         * entry points
         */
        for (check = (union pnp_bios_install_struct *)__va(0xf0000);
             check < (union pnp_bios_install_struct *)__va(0xffff0);
             check = (void *)check + 16) {
                if (check->fields.signature != PNP_SIGNATURE)
                        continue;
                printk(KERN_INFO
                       "PnPBIOS: Found PnP BIOS installation structure at 0x%p\n",
                       check);
                length = check->fields.length;
                if (!length) {
                        printk(KERN_ERR
                               "PnPBIOS: installation structure is invalid, skipping\n");
                        continue;
                }
                for (sum = 0, i = 0; i < length; i++)
                        sum += check->chars[i];
                if (sum) {
                        printk(KERN_ERR
                               "PnPBIOS: installation structure is corrupted, skipping\n");
                        continue;
                }
                if (check->fields.version < 0x10) {
                        printk(KERN_WARNING
                               "PnPBIOS: PnP BIOS version %d.%d is not supported\n",
                               check->fields.version >> 4,
                               check->fields.version & 15);
                        continue;
                }
                printk(KERN_INFO
                       "PnPBIOS: PnP BIOS version %d.%d, entry 0x%x:0x%x, dseg 0x%x\n",
                       check->fields.version >> 4, check->fields.version & 15,
                       check->fields.pm16cseg, check->fields.pm16offset,
                       check->fields.pm16dseg);
                pnp_bios_install = check;
                return 1;
        }

        printk(KERN_INFO "PnPBIOS: PnP BIOS support was not detected.\n");
        return 0;
}

static int __init exploding_pnp_bios(const struct dmi_system_id *d)
{
        printk(KERN_WARNING "%s detected. Disabling PnPBIOS\n", d->ident);
        return 0;
}

static const struct dmi_system_id pnpbios_dmi_table[] __initconst = {
        {                       /* PnPBIOS GPF on boot */
         .callback = exploding_pnp_bios,
         .ident = "Higraded P14H",
         .matches = {
                     DMI_MATCH(DMI_BIOS_VENDOR, "American Megatrends Inc."),
                     DMI_MATCH(DMI_BIOS_VERSION, "07.00T"),
                     DMI_MATCH(DMI_SYS_VENDOR, "Higraded"),
                     DMI_MATCH(DMI_PRODUCT_NAME, "P14H"),
                     },
         },
        {                       /* PnPBIOS GPF on boot */
         .callback = exploding_pnp_bios,
         .ident = "ASUS P4P800",
         .matches = {
                     DMI_MATCH(DMI_BOARD_VENDOR, "ASUSTeK Computer Inc."),
                     DMI_MATCH(DMI_BOARD_NAME, "P4P800"),
                     },
         },
        {}
};

static int __init pnpbios_init(void)
{
        int ret;

        if (pnpbios_disabled || dmi_check_system(pnpbios_dmi_table) ||
            arch_pnpbios_disabled()) {
                printk(KERN_INFO "PnPBIOS: Disabled\n");
                return -ENODEV;
        }

#ifdef CONFIG_PNPACPI
        if (!acpi_disabled && !pnpacpi_disabled) {
                pnpbios_disabled = 1;
                printk(KERN_INFO "PnPBIOS: Disabled by ACPI PNP\n");
                return -ENODEV;
        }
#endif                          /* CONFIG_ACPI */

        /* scan the system for pnpbios support */
        if (!pnpbios_probe_system())
                return -ENODEV;

        /* make preparations for bios calls */
        pnpbios_calls_init(pnp_bios_install);

        /* read the node info */
        ret = pnp_bios_dev_node_info(&node_info);
        if (ret) {
                printk(KERN_ERR
                       "PnPBIOS: Unable to get node info.  Aborting.\n");
                return ret;
        }

        /* register with the pnp layer */
        ret = pnp_register_protocol(&pnpbios_protocol);
        if (ret) {
                printk(KERN_ERR
                       "PnPBIOS: Unable to register driver.  Aborting.\n");
                return ret;
        }

        /* start the proc interface */
        ret = pnpbios_proc_init();
        if (ret)
                printk(KERN_ERR "PnPBIOS: Failed to create proc interface.\n");

        /* scan for pnpbios devices */
        build_devlist();

        pnp_platform_devices = 1;
        return 0;
}

fs_initcall(pnpbios_init);

static int __init pnpbios_thread_init(void)
{
        struct task_struct *task;

        if (pnpbios_disabled)
                return 0;

        init_completion(&unload_sem);
        task = kthread_run(pnp_dock_thread, NULL, "kpnpbiosd");
        return PTR_ERR_OR_ZERO(task);
}

/* Start the kernel thread later: */
device_initcall(pnpbios_thread_init);

EXPORT_SYMBOL(pnpbios_protocol);