pci_hotplug_core.c

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/*
 * PCI HotPlug Controller Core
 *
 * Copyright (C) 2001-2002 Greg Kroah-Hartman ([email protected])
 * Copyright (C) 2001-2002 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.
 *
 * Send feedback to <[email protected]>
 *
 */

#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/list.h>
#include <linux/kobject.h>
#include <linux/sysfs.h>
#include <linux/pagemap.h>
#include <linux/init.h>
#include <linux/mount.h>
#include <linux/namei.h>
#include <linux/mutex.h>
#include <linux/pci.h>
#include <linux/pci_hotplug.h>
#include <asm/uaccess.h>
#include "../pci.h"

#define MY_NAME "pci_hotplug"

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


/* local variables */
static bool debug;

#define DRIVER_VERSION  "0.5"
#define DRIVER_AUTHOR   "Greg Kroah-Hartman <[email protected]>, Scott Murray <[email protected]>"
#define DRIVER_DESC "PCI Hot Plug PCI Core"



static LIST_HEAD(pci_hotplug_slot_list);
static DEFINE_MUTEX(pci_hp_mutex);

#ifdef CONFIG_HOTPLUG_PCI_CPCI
extern int cpci_hotplug_init(int debug);
extern void cpci_hotplug_exit(void);
#else
static inline int cpci_hotplug_init(int debug) { return 0; }
static inline void cpci_hotplug_exit(void) { }
#endif

/* Weee, fun with macros... */
#define GET_STATUS(name,type)   \
static int get_##name (struct hotplug_slot *slot, type *value)      \
{                                   \
    struct hotplug_slot_ops *ops = slot->ops;           \
    int retval = 0;                         \
    if (!try_module_get(ops->owner))                \
        return -ENODEV;                     \
    if (ops->get_##name)                        \
        retval = ops->get_##name(slot, value);          \
    else                                \
        *value = slot->info->name;              \
    module_put(ops->owner);                     \
    return retval;                          \
}

GET_STATUS(power_status, u8)
GET_STATUS(attention_status, u8)
GET_STATUS(latch_status, u8)
GET_STATUS(adapter_status, u8)

static ssize_t power_read_file(struct pci_slot *slot, char *buf)
{
    int retval;
    u8 value;

    retval = get_power_status(slot->hotplug, &value);
    if (retval)
        goto exit;
    retval = sprintf (buf, "%d\n", value);
exit:
    return retval;
}

static ssize_t power_write_file(struct pci_slot *pci_slot, const char *buf,
        size_t count)
{
    struct hotplug_slot *slot = pci_slot->hotplug;
    unsigned long lpower;
    u8 power;
    int retval = 0;

    lpower = simple_strtoul (buf, NULL, 10);
    power = (u8)(lpower & 0xff);
    dbg ("power = %d\n", power);

    if (!try_module_get(slot->ops->owner)) {
        retval = -ENODEV;
        goto exit;
    }
    switch (power) {
        case 0:
            if (slot->ops->disable_slot)
                retval = slot->ops->disable_slot(slot);
            break;

        case 1:
            if (slot->ops->enable_slot)
                retval = slot->ops->enable_slot(slot);
            break;

        default:
            err ("Illegal value specified for power\n");
            retval = -EINVAL;
    }
    module_put(slot->ops->owner);

exit:   
    if (retval)
        return retval;
    return count;
}

static struct pci_slot_attribute hotplug_slot_attr_power = {
    .attr = {.name = "power", .mode = S_IFREG | S_IRUGO | S_IWUSR},
    .show = power_read_file,
    .store = power_write_file
};

static ssize_t attention_read_file(struct pci_slot *slot, char *buf)
{
    int retval;
    u8 value;

    retval = get_attention_status(slot->hotplug, &value);
    if (retval)
        goto exit;
    retval = sprintf(buf, "%d\n", value);

exit:
    return retval;
}

static ssize_t attention_write_file(struct pci_slot *slot, const char *buf,
        size_t count)
{
    struct hotplug_slot_ops *ops = slot->hotplug->ops;
    unsigned long lattention;
    u8 attention;
    int retval = 0;

    lattention = simple_strtoul (buf, NULL, 10);
    attention = (u8)(lattention & 0xff);
    dbg (" - attention = %d\n", attention);

    if (!try_module_get(ops->owner)) {
        retval = -ENODEV;
        goto exit;
    }
    if (ops->set_attention_status)
        retval = ops->set_attention_status(slot->hotplug, attention);
    module_put(ops->owner);

exit:   
    if (retval)
        return retval;
    return count;
}

static struct pci_slot_attribute hotplug_slot_attr_attention = {
    .attr = {.name = "attention", .mode = S_IFREG | S_IRUGO | S_IWUSR},
    .show = attention_read_file,
    .store = attention_write_file
};

static ssize_t latch_read_file(struct pci_slot *slot, char *buf)
{
    int retval;
    u8 value;

    retval = get_latch_status(slot->hotplug, &value);
    if (retval)
        goto exit;
    retval = sprintf (buf, "%d\n", value);

exit:
    return retval;
}

static struct pci_slot_attribute hotplug_slot_attr_latch = {
    .attr = {.name = "latch", .mode = S_IFREG | S_IRUGO},
    .show = latch_read_file,
};

static ssize_t presence_read_file(struct pci_slot *slot, char *buf)
{
    int retval;
    u8 value;

    retval = get_adapter_status(slot->hotplug, &value);
    if (retval)
        goto exit;
    retval = sprintf (buf, "%d\n", value);

exit:
    return retval;
}

static struct pci_slot_attribute hotplug_slot_attr_presence = {
    .attr = {.name = "adapter", .mode = S_IFREG | S_IRUGO},
    .show = presence_read_file,
};

static ssize_t test_write_file(struct pci_slot *pci_slot, const char *buf,
        size_t count)
{
    struct hotplug_slot *slot = pci_slot->hotplug;
    unsigned long ltest;
    u32 test;
    int retval = 0;

    ltest = simple_strtoul (buf, NULL, 10);
    test = (u32)(ltest & 0xffffffff);
    dbg ("test = %d\n", test);

    if (!try_module_get(slot->ops->owner)) {
        retval = -ENODEV;
        goto exit;
    }
    if (slot->ops->hardware_test)
        retval = slot->ops->hardware_test(slot, test);
    module_put(slot->ops->owner);

exit:   
    if (retval)
        return retval;
    return count;
}

static struct pci_slot_attribute hotplug_slot_attr_test = {
    .attr = {.name = "test", .mode = S_IFREG | S_IRUGO | S_IWUSR},
    .store = test_write_file
};

static bool has_power_file(struct pci_slot *pci_slot)
{
    struct hotplug_slot *slot = pci_slot->hotplug;
    if ((!slot) || (!slot->ops))
        return false;
    if ((slot->ops->enable_slot) ||
        (slot->ops->disable_slot) ||
        (slot->ops->get_power_status))
        return true;
    return false;
}

static bool has_attention_file(struct pci_slot *pci_slot)
{
    struct hotplug_slot *slot = pci_slot->hotplug;
    if ((!slot) || (!slot->ops))
        return false;
    if ((slot->ops->set_attention_status) ||
        (slot->ops->get_attention_status))
        return true;
    return false;
}

static bool has_latch_file(struct pci_slot *pci_slot)
{
    struct hotplug_slot *slot = pci_slot->hotplug;
    if ((!slot) || (!slot->ops))
        return false;
    if (slot->ops->get_latch_status)
        return true;
    return false;
}

static bool has_adapter_file(struct pci_slot *pci_slot)
{
    struct hotplug_slot *slot = pci_slot->hotplug;
    if ((!slot) || (!slot->ops))
        return false;
    if (slot->ops->get_adapter_status)
        return true;
    return false;
}

static bool has_test_file(struct pci_slot *pci_slot)
{
    struct hotplug_slot *slot = pci_slot->hotplug;
    if ((!slot) || (!slot->ops))
        return false;
    if (slot->ops->hardware_test)
        return true;
    return false;
}

static int fs_add_slot(struct pci_slot *slot)
{
    int retval = 0;

    /* Create symbolic link to the hotplug driver module */
    pci_hp_create_module_link(slot);

    if (has_power_file(slot)) {
        retval = sysfs_create_file(&slot->kobj,
                       &hotplug_slot_attr_power.attr);
        if (retval)
            goto exit_power;
    }

    if (has_attention_file(slot)) {
        retval = sysfs_create_file(&slot->kobj,
                       &hotplug_slot_attr_attention.attr);
        if (retval)
            goto exit_attention;
    }

    if (has_latch_file(slot)) {
        retval = sysfs_create_file(&slot->kobj,
                       &hotplug_slot_attr_latch.attr);
        if (retval)
            goto exit_latch;
    }

    if (has_adapter_file(slot)) {
        retval = sysfs_create_file(&slot->kobj,
                       &hotplug_slot_attr_presence.attr);
        if (retval)
            goto exit_adapter;
    }

    if (has_test_file(slot)) {
        retval = sysfs_create_file(&slot->kobj,
                       &hotplug_slot_attr_test.attr);
        if (retval)
            goto exit_test;
    }

    goto exit;

exit_test:
    if (has_adapter_file(slot))
        sysfs_remove_file(&slot->kobj,
                  &hotplug_slot_attr_presence.attr);
exit_adapter:
    if (has_latch_file(slot))
        sysfs_remove_file(&slot->kobj, &hotplug_slot_attr_latch.attr);
exit_latch:
    if (has_attention_file(slot))
        sysfs_remove_file(&slot->kobj,
                  &hotplug_slot_attr_attention.attr);
exit_attention:
    if (has_power_file(slot))
        sysfs_remove_file(&slot->kobj, &hotplug_slot_attr_power.attr);
exit_power:
    pci_hp_remove_module_link(slot);
exit:
    return retval;
}

static void fs_remove_slot(struct pci_slot *slot)
{
    if (has_power_file(slot))
        sysfs_remove_file(&slot->kobj, &hotplug_slot_attr_power.attr);

    if (has_attention_file(slot))
        sysfs_remove_file(&slot->kobj,
                  &hotplug_slot_attr_attention.attr);

    if (has_latch_file(slot))
        sysfs_remove_file(&slot->kobj, &hotplug_slot_attr_latch.attr);

    if (has_adapter_file(slot))
        sysfs_remove_file(&slot->kobj,
                  &hotplug_slot_attr_presence.attr);

    if (has_test_file(slot))
        sysfs_remove_file(&slot->kobj, &hotplug_slot_attr_test.attr);

    pci_hp_remove_module_link(slot);
}

static struct hotplug_slot *get_slot_from_name (const char *name)
{
    struct hotplug_slot *slot;
    struct list_head *tmp;

    list_for_each (tmp, &pci_hotplug_slot_list) {
        slot = list_entry (tmp, struct hotplug_slot, slot_list);
        if (strcmp(hotplug_slot_name(slot), name) == 0)
            return slot;
    }
    return NULL;
}

int __pci_hp_register(struct hotplug_slot *slot, struct pci_bus *bus,
              int devnr, const char *name,
              struct module *owner, const char *mod_name)
{
    int result;
    struct pci_slot *pci_slot;

    if (slot == NULL)
        return -ENODEV;
    if ((slot->info == NULL) || (slot->ops == NULL))
        return -EINVAL;
    if (slot->release == NULL) {
        dbg("Why are you trying to register a hotplug slot "
            "without a proper release function?\n");
        return -EINVAL;
    }

    slot->ops->owner = owner;
    slot->ops->mod_name = mod_name;

    mutex_lock(&pci_hp_mutex);
    /*
     * No problems if we call this interface from both ACPI_PCI_SLOT
     * driver and call it here again. If we've already created the
     * pci_slot, the interface will simply bump the refcount.
     */
    pci_slot = pci_create_slot(bus, devnr, name, slot);
    if (IS_ERR(pci_slot)) {
        result = PTR_ERR(pci_slot);
        goto out;
    }

    slot->pci_slot = pci_slot;
    pci_slot->hotplug = slot;

    list_add(&slot->slot_list, &pci_hotplug_slot_list);

    result = fs_add_slot(pci_slot);
    kobject_uevent(&pci_slot->kobj, KOBJ_ADD);
    dbg("Added slot %s to the list\n", name);
out:
    mutex_unlock(&pci_hp_mutex);
    return result;
}

int pci_hp_deregister(struct hotplug_slot *hotplug)
{
    struct hotplug_slot *temp;
    struct pci_slot *slot;

    if (!hotplug)
        return -ENODEV;

    mutex_lock(&pci_hp_mutex);
    temp = get_slot_from_name(hotplug_slot_name(hotplug));
    if (temp != hotplug) {
        mutex_unlock(&pci_hp_mutex);
        return -ENODEV;
    }

    list_del(&hotplug->slot_list);

    slot = hotplug->pci_slot;
    fs_remove_slot(slot);
    dbg("Removed slot %s from the list\n", hotplug_slot_name(hotplug));

    hotplug->release(hotplug);
    slot->hotplug = NULL;
    pci_destroy_slot(slot);
    mutex_unlock(&pci_hp_mutex);

    return 0;
}

int __must_check pci_hp_change_slot_info(struct hotplug_slot *hotplug,
                     struct hotplug_slot_info *info)
{
    struct pci_slot *slot;
    if (!hotplug || !info)
        return -ENODEV;
    slot = hotplug->pci_slot;

    memcpy(hotplug->info, info, sizeof(struct hotplug_slot_info));

    return 0;
}

static int __init pci_hotplug_init (void)
{
    int result;

    result = cpci_hotplug_init(debug);
    if (result) {
        err ("cpci_hotplug_init with error %d\n", result);
        goto err_cpci;
    }

    info (DRIVER_DESC " version: " DRIVER_VERSION "\n");

err_cpci:
    return result;
}

static void __exit pci_hotplug_exit (void)
{
    cpci_hotplug_exit();
}

module_init(pci_hotplug_init);
module_exit(pci_hotplug_exit);

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");

EXPORT_SYMBOL_GPL(__pci_hp_register);
EXPORT_SYMBOL_GPL(pci_hp_deregister);
EXPORT_SYMBOL_GPL(pci_hp_change_slot_info);