// SPDX-License-Identifier: GPL-2.0+
/*
 * cpcihp_generic.c
 *
 * Generic port I/O CompactPCI driver
 *
 * Copyright 2002 SOMA Networks, Inc.
 * Copyright 2001 Intel San Luis Obispo
 * Copyright 2000,2001 MontaVista Software Inc.
 *
 * This generic CompactPCI hotplug driver should allow using the PCI hotplug
 * mechanism on any CompactPCI board that exposes the #ENUM signal as a bit
 * in a system register that can be read through standard port I/O.
 *
 * Send feedback to <scottm@somanetworks.com>
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/errno.h>
#include <linux/pci.h>
#include <linux/string.h>
#include "cpci_hotplug.h"

#define DRIVER_VERSION  "0.1"
#define DRIVER_AUTHOR   "Scott Murray <scottm@somanetworks.com>"
#define DRIVER_DESC     "Generic port I/O CompactPCI Hot Plug Driver"

#if !defined(MODULE)
#define MY_NAME "cpcihp_generic"
#else
#define MY_NAME THIS_MODULE->name
#endif

#define dbg(format, arg...)                                     \
        do {                                                    \
                if (debug)                                      \
                        printk(KERN_DEBUG "%s: " format "\n",   \
                                MY_NAME, ## arg);               \
        } while (0)
#define err(format, arg...) printk(KERN_ERR "%s: " format "\n", MY_NAME, ## arg)
#define info(format, arg...) printk(KERN_INFO "%s: " format "\n", MY_NAME, ## arg)
#define warn(format, arg...) printk(KERN_WARNING "%s: " format "\n", MY_NAME, ## arg)

/* local variables */
static bool debug;
static char *bridge;
static u8 bridge_busnr;
static u8 bridge_slot;
static struct pci_bus *bus;
static u8 first_slot;
static u8 last_slot;
static u16 port;
static unsigned int enum_bit;
static u8 enum_mask;

static struct cpci_hp_controller_ops generic_hpc_ops;
static struct cpci_hp_controller generic_hpc;

static int __init validate_parameters(void)
{
        char *str;
        char *p;
        unsigned long tmp;

        if (!bridge) {
                info("not configured, disabling.");
                return -EINVAL;
        }
        str = bridge;
        if (!*str)
                return -EINVAL;

        tmp = simple_strtoul(str, &p, 16);
        if (p == str || tmp > 0xff) {
                err("Invalid hotplug bus bridge device bus number");
                return -EINVAL;
        }
        bridge_busnr = (u8) tmp;
        dbg("bridge_busnr = 0x%02x", bridge_busnr);
        if (*p != ':') {
                err("Invalid hotplug bus bridge device");
                return -EINVAL;
        }
        str = p + 1;
        tmp = simple_strtoul(str, &p, 16);
        if (p == str || tmp > 0x1f) {
                err("Invalid hotplug bus bridge device slot number");
                return -EINVAL;
        }
        bridge_slot = (u8) tmp;
        dbg("bridge_slot = 0x%02x", bridge_slot);

        dbg("first_slot = 0x%02x", first_slot);
        dbg("last_slot = 0x%02x", last_slot);
        if (!(first_slot && last_slot)) {
                err("Need to specify first_slot and last_slot");
                return -EINVAL;
        }
        if (last_slot < first_slot) {
                err("first_slot must be less than last_slot");
                return -EINVAL;
        }

        dbg("port = 0x%04x", port);
        dbg("enum_bit = 0x%02x", enum_bit);
        if (enum_bit > 7) {
                err("Invalid #ENUM bit");
                return -EINVAL;
        }
        enum_mask = 1 << enum_bit;
        return 0;
}

static int query_enum(void)
{
        u8 value;

        value = inb_p(port);
        return ((value & enum_mask) == enum_mask);
}

static int __init cpcihp_generic_init(void)
{
        int status;
        struct resource *r;
        struct pci_dev *dev;

        info(DRIVER_DESC " version: " DRIVER_VERSION);
        status = validate_parameters();
        if (status)
                return status;

        r = request_region(port, 1, "#ENUM hotswap signal register");
        if (!r)
                return -EBUSY;

        dev = pci_get_domain_bus_and_slot(0, bridge_busnr,
                                          PCI_DEVFN(bridge_slot, 0));
        if (!dev || dev->hdr_type != PCI_HEADER_TYPE_BRIDGE) {
                err("Invalid bridge device %s", bridge);
                pci_dev_put(dev);
                return -EINVAL;
        }
        bus = dev->subordinate;
        pci_dev_put(dev);

        memset(&generic_hpc, 0, sizeof(struct cpci_hp_controller));
        generic_hpc_ops.query_enum = query_enum;
        generic_hpc.ops = &generic_hpc_ops;

        status = cpci_hp_register_controller(&generic_hpc);
        if (status != 0) {
                err("Could not register cPCI hotplug controller");
                return -ENODEV;
        }
        dbg("registered controller");

        status = cpci_hp_register_bus(bus, first_slot, last_slot);
        if (status != 0) {
                err("Could not register cPCI hotplug bus");
                goto init_bus_register_error;
        }
        dbg("registered bus");

        status = cpci_hp_start();
        if (status != 0) {
                err("Could not started cPCI hotplug system");
                goto init_start_error;
        }
        dbg("started cpci hp system");
        return 0;
init_start_error:
        cpci_hp_unregister_bus(bus);
init_bus_register_error:
        cpci_hp_unregister_controller(&generic_hpc);
        err("status = %d", status);
        return status;

}

static void __exit cpcihp_generic_exit(void)
{
        cpci_hp_stop();
        cpci_hp_unregister_bus(bus);
        cpci_hp_unregister_controller(&generic_hpc);
        release_region(port, 1);
}

module_init(cpcihp_generic_init);
module_exit(cpcihp_generic_exit);

MODULE_AUTHOR(DRIVER_AUTHOR);
MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_LICENSE("GPL");
module_param(debug, bool, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(debug, "Debugging mode enabled or not");
module_param(bridge, charp, 0);
MODULE_PARM_DESC(bridge, "Hotswap bus bridge device, <bus>:<slot> (bus and slot are in hexadecimal)");
module_param(first_slot, byte, 0);
MODULE_PARM_DESC(first_slot, "Hotswap bus first slot number");
module_param(last_slot, byte, 0);
MODULE_PARM_DESC(last_slot, "Hotswap bus last slot number");
module_param_hw(port, ushort, ioport, 0);
MODULE_PARM_DESC(port, "#ENUM signal I/O port");
module_param(enum_bit, uint, 0);
MODULE_PARM_DESC(enum_bit, "#ENUM signal bit (0-7)");