pcihp_skeleton.c

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/*
 * PCI Hot Plug Controller Skeleton Driver - 0.3
 *
 * Copyright (C) 2001,2003 Greg Kroah-Hartman ([email protected])
 * Copyright (C) 2001,2003 IBM Corp.
 *
 * 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 as published by
 * the Free Software Foundation; either version 2 of the License, or (at
 * your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
 * NON INFRINGEMENT.  See the GNU General Public License for more
 * details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 * This driver is to be used as a skeleton driver to show how to interface
 * with the pci hotplug core easily.
 *
 * Send feedback to <[email protected]>
 *
 */

#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/pci.h>
#include <linux/pci_hotplug.h>
#include <linux/init.h>

#define SLOT_NAME_SIZE  10
struct slot {
    u8 number;
    struct hotplug_slot *hotplug_slot;
    struct list_head slot_list;
    char name[SLOT_NAME_SIZE];
};

static LIST_HEAD(slot_list);

#define MY_NAME "pcihp_skeleton"

#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 int num_slots;

#define DRIVER_VERSION  "0.3"
#define DRIVER_AUTHOR   "Greg Kroah-Hartman <[email protected]>"
#define DRIVER_DESC "Hot Plug PCI Controller Skeleton Driver"

MODULE_AUTHOR(DRIVER_AUTHOR);
MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_LICENSE("GPL");
module_param(debug, bool, 0644);
MODULE_PARM_DESC(debug, "Debugging mode enabled or not");

static int enable_slot      (struct hotplug_slot *slot);
static int disable_slot     (struct hotplug_slot *slot);
static int set_attention_status (struct hotplug_slot *slot, u8 value);
static int hardware_test    (struct hotplug_slot *slot, u32 value);
static int get_power_status (struct hotplug_slot *slot, u8 *value);
static int get_attention_status (struct hotplug_slot *slot, u8 *value);
static int get_latch_status (struct hotplug_slot *slot, u8 *value);
static int get_adapter_status   (struct hotplug_slot *slot, u8 *value);

static struct hotplug_slot_ops skel_hotplug_slot_ops = {
    .enable_slot =      enable_slot,
    .disable_slot =     disable_slot,
    .set_attention_status = set_attention_status,
    .hardware_test =    hardware_test,
    .get_power_status = get_power_status,
    .get_attention_status = get_attention_status,
    .get_latch_status = get_latch_status,
    .get_adapter_status =   get_adapter_status,
};

static int enable_slot(struct hotplug_slot *hotplug_slot)
{
    struct slot *slot = hotplug_slot->private;
    int retval = 0;

    dbg("%s - physical_slot = %s\n", __func__, hotplug_slot->name);

    /*
     * Fill in code here to enable the specified slot
     */

    return retval;
}

static int disable_slot(struct hotplug_slot *hotplug_slot)
{
    struct slot *slot = hotplug_slot->private;
    int retval = 0;

    dbg("%s - physical_slot = %s\n", __func__, hotplug_slot->name);

    /*
     * Fill in code here to disable the specified slot
     */

    return retval;
}

static int set_attention_status(struct hotplug_slot *hotplug_slot, u8 status)
{
    struct slot *slot = hotplug_slot->private;
    int retval = 0;

    dbg("%s - physical_slot = %s\n", __func__, hotplug_slot->name);

    switch (status) {
        case 0:
            /*
             * Fill in code here to turn light off
             */
            break;

        case 1:
        default:
            /*
             * Fill in code here to turn light on
             */
            break;
    }

    return retval;
}

static int hardware_test(struct hotplug_slot *hotplug_slot, u32 value)
{
    struct slot *slot = hotplug_slot->private;
    int retval = 0;

    dbg("%s - physical_slot = %s\n", __func__, hotplug_slot->name);

    switch (value) {
        case 0:
            /* Specify a test here */
            break;
        case 1:
            /* Specify another test here */
            break;
    }

    return retval;
}

static int get_power_status(struct hotplug_slot *hotplug_slot, u8 *value)
{
    struct slot *slot = hotplug_slot->private;
    int retval = 0;

    dbg("%s - physical_slot = %s\n", __func__, hotplug_slot->name);

    /*
     * Fill in logic to get the current power status of the specific
     * slot and store it in the *value location.
     */

    return retval;
}

static int get_attention_status(struct hotplug_slot *hotplug_slot, u8 *value)
{
    struct slot *slot = hotplug_slot->private;
    int retval = 0;

    dbg("%s - physical_slot = %s\n", __func__, hotplug_slot->name);

    /*
     * Fill in logic to get the current attention status of the specific
     * slot and store it in the *value location.
     */

    return retval;
}

static int get_latch_status(struct hotplug_slot *hotplug_slot, u8 *value)
{
    struct slot *slot = hotplug_slot->private;
    int retval = 0;

    dbg("%s - physical_slot = %s\n", __func__, hotplug_slot->name);

    /*
     * Fill in logic to get the current latch status of the specific
     * slot and store it in the *value location.
     */

    return retval;
}

static int get_adapter_status(struct hotplug_slot *hotplug_slot, u8 *value)
{
    struct slot *slot = hotplug_slot->private;
    int retval = 0;

    dbg("%s - physical_slot = %s\n", __func__, hotplug_slot->name);

    /*
     * Fill in logic to get the current adapter status of the specific
     * slot and store it in the *value location.
     */

    return retval;
}

static void release_slot(struct hotplug_slot *hotplug_slot)
{
    struct slot *slot = hotplug_slot->private;

    dbg("%s - physical_slot = %s\n", __func__, hotplug_slot->name);
    kfree(slot->hotplug_slot->info);
    kfree(slot->hotplug_slot);
    kfree(slot);
}

static void make_slot_name(struct slot *slot)
{
    /*
     * Stupid way to make a filename out of the slot name.
     * replace this if your hardware provides a better way to name slots.
     */
    snprintf(slot->hotplug_slot->name, SLOT_NAME_SIZE, "%d", slot->number);
}

static int __init init_slots(void)
{
    struct slot *slot;
    struct hotplug_slot *hotplug_slot;
    struct hotplug_slot_info *info;
    int retval;
    int i;

    /*
     * Create a structure for each slot, and register that slot
     * with the pci_hotplug subsystem.
     */
    for (i = 0; i < num_slots; ++i) {
        slot = kzalloc(sizeof(*slot), GFP_KERNEL);
        if (!slot) {
            retval = -ENOMEM;
            goto error;
        }

        hotplug_slot = kzalloc(sizeof(*hotplug_slot), GFP_KERNEL);
        if (!hotplug_slot) {
            retval = -ENOMEM;
            goto error_slot;
        }
        slot->hotplug_slot = hotplug_slot;

        info = kzalloc(sizeof(*info), GFP_KERNEL);
        if (!info) {
            retval = -ENOMEM;
            goto error_hpslot;
        }
        hotplug_slot->info = info;

        slot->number = i;

        hotplug_slot->name = slot->name;
        hotplug_slot->private = slot;
        hotplug_slot->release = &release_slot;
        make_slot_name(slot);
        hotplug_slot->ops = &skel_hotplug_slot_ops;
        
        /*
         * Initialize the slot info structure with some known
         * good values.
         */
        get_power_status(hotplug_slot, &info->power_status);
        get_attention_status(hotplug_slot, &info->attention_status);
        get_latch_status(hotplug_slot, &info->latch_status);
        get_adapter_status(hotplug_slot, &info->adapter_status);
        
        dbg("registering slot %d\n", i);
        retval = pci_hp_register(slot->hotplug_slot);
        if (retval) {
            err("pci_hp_register failed with error %d\n", retval);
            goto error_info;
        }

        /* add slot to our internal list */
        list_add(&slot->slot_list, &slot_list);
    }

    return 0;
error_info:
    kfree(info);
error_hpslot:
    kfree(hotplug_slot);
error_slot:
    kfree(slot);
error:
    return retval;
}

static void __exit cleanup_slots(void)
{
    struct list_head *tmp;
    struct list_head *next;
    struct slot *slot;

    /*
     * Unregister all of our slots with the pci_hotplug subsystem.
     * Memory will be freed in release_slot() callback after slot's
     * lifespan is finished.
     */
    list_for_each_safe(tmp, next, &slot_list) {
        slot = list_entry(tmp, struct slot, slot_list);
        list_del(&slot->slot_list);
        pci_hp_deregister(slot->hotplug_slot);
    }
}
        
static int __init pcihp_skel_init(void)
{
    int retval;

    info(DRIVER_DESC " version: " DRIVER_VERSION "\n");
    /*
     * Do specific initialization stuff for your driver here
     * like initializing your controller hardware (if any) and
     * determining the number of slots you have in the system
     * right now.
     */
    num_slots = 5;

    return init_slots();
}

static void __exit pcihp_skel_exit(void)
{
    /*
     * Clean everything up.
     */
    cleanup_slots();
}

module_init(pcihp_skel_init);
module_exit(pcihp_skel_exit);