driver.c

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/*
 *  Functions to handle I2O drivers (OSMs) and I2O bus type for sysfs
 *
 *  Copyright (C) 2004  Markus Lidel <[email protected]>
 *
 *  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.
 *
 *  Fixes/additions:
 *      Markus Lidel <[email protected]>
 *          initial version.
 */

#include <linux/device.h>
#include <linux/module.h>
#include <linux/rwsem.h>
#include <linux/i2o.h>
#include <linux/workqueue.h>
#include <linux/string.h>
#include <linux/slab.h>
#include "core.h"

#define OSM_NAME    "i2o"

/* max_drivers - Maximum I2O drivers (OSMs) which could be registered */
static unsigned int i2o_max_drivers = I2O_MAX_DRIVERS;
module_param_named(max_drivers, i2o_max_drivers, uint, 0);
MODULE_PARM_DESC(max_drivers, "maximum number of OSM's to support");

/* I2O drivers lock and array */
static spinlock_t i2o_drivers_lock;
static struct i2o_driver **i2o_drivers;

static int i2o_bus_match(struct device *dev, struct device_driver *drv)
{
    struct i2o_device *i2o_dev = to_i2o_device(dev);
    struct i2o_driver *i2o_drv = to_i2o_driver(drv);
    struct i2o_class_id *ids = i2o_drv->classes;

    if (ids)
        while (ids->class_id != I2O_CLASS_END) {
            if (ids->class_id == i2o_dev->lct_data.class_id)
                return 1;
            ids++;
        }
    return 0;
};

/* I2O bus type */
struct bus_type i2o_bus_type = {
    .name = "i2o",
    .match = i2o_bus_match,
    .dev_attrs = i2o_device_attrs
};

int i2o_driver_register(struct i2o_driver *drv)
{
    struct i2o_controller *c;
    int i;
    int rc = 0;
    unsigned long flags;

    osm_debug("Register driver %s\n", drv->name);

    if (drv->event) {
        drv->event_queue = alloc_workqueue(drv->name,
                           WQ_MEM_RECLAIM, 1);
        if (!drv->event_queue) {
            osm_err("Could not initialize event queue for driver "
                "%s\n", drv->name);
            return -EFAULT;
        }
        osm_debug("Event queue initialized for driver %s\n", drv->name);
    } else
        drv->event_queue = NULL;

    drv->driver.name = drv->name;
    drv->driver.bus = &i2o_bus_type;

    spin_lock_irqsave(&i2o_drivers_lock, flags);

    for (i = 0; i2o_drivers[i]; i++)
        if (i >= i2o_max_drivers) {
            osm_err("too many drivers registered, increase "
                "max_drivers\n");
            spin_unlock_irqrestore(&i2o_drivers_lock, flags);
            return -EFAULT;
        }

    drv->context = i;
    i2o_drivers[i] = drv;

    spin_unlock_irqrestore(&i2o_drivers_lock, flags);

    osm_debug("driver %s gets context id %d\n", drv->name, drv->context);

    list_for_each_entry(c, &i2o_controllers, list) {
        struct i2o_device *i2o_dev;

        i2o_driver_notify_controller_add(drv, c);
        list_for_each_entry(i2o_dev, &c->devices, list)
            i2o_driver_notify_device_add(drv, i2o_dev);
    }

    rc = driver_register(&drv->driver);
    if (rc) {
        if (drv->event) {
            destroy_workqueue(drv->event_queue);
            drv->event_queue = NULL;
        }
    }

    return rc;
};

void i2o_driver_unregister(struct i2o_driver *drv)
{
    struct i2o_controller *c;
    unsigned long flags;

    osm_debug("unregister driver %s\n", drv->name);

    driver_unregister(&drv->driver);

    list_for_each_entry(c, &i2o_controllers, list) {
        struct i2o_device *i2o_dev;

        list_for_each_entry(i2o_dev, &c->devices, list)
            i2o_driver_notify_device_remove(drv, i2o_dev);

        i2o_driver_notify_controller_remove(drv, c);
    }

    spin_lock_irqsave(&i2o_drivers_lock, flags);
    i2o_drivers[drv->context] = NULL;
    spin_unlock_irqrestore(&i2o_drivers_lock, flags);

    if (drv->event_queue) {
        destroy_workqueue(drv->event_queue);
        drv->event_queue = NULL;
        osm_debug("event queue removed for %s\n", drv->name);
    }
};

int i2o_driver_dispatch(struct i2o_controller *c, u32 m)
{
    struct i2o_driver *drv;
    struct i2o_message *msg = i2o_msg_out_to_virt(c, m);
    u32 context = le32_to_cpu(msg->u.s.icntxt);
    unsigned long flags;

    if (unlikely(context >= i2o_max_drivers)) {
        osm_warn("%s: Spurious reply to unknown driver %d\n", c->name,
             context);
        return -EIO;
    }

    spin_lock_irqsave(&i2o_drivers_lock, flags);
    drv = i2o_drivers[context];
    spin_unlock_irqrestore(&i2o_drivers_lock, flags);

    if (unlikely(!drv)) {
        osm_warn("%s: Spurious reply to unknown driver %d\n", c->name,
             context);
        return -EIO;
    }

    if ((le32_to_cpu(msg->u.head[1]) >> 24) == I2O_CMD_UTIL_EVT_REGISTER) {
        struct i2o_device *dev, *tmp;
        struct i2o_event *evt;
        u16 size;
        u16 tid = le32_to_cpu(msg->u.head[1]) & 0xfff;

        osm_debug("event received from device %d\n", tid);

        if (!drv->event)
            return -EIO;

        /* cut of header from message size (in 32-bit words) */
        size = (le32_to_cpu(msg->u.head[0]) >> 16) - 5;

        evt = kzalloc(size * 4 + sizeof(*evt), GFP_ATOMIC);
        if (!evt)
            return -ENOMEM;

        evt->size = size;
        evt->tcntxt = le32_to_cpu(msg->u.s.tcntxt);
        evt->event_indicator = le32_to_cpu(msg->body[0]);
        memcpy(&evt->data, &msg->body[1], size * 4);

        list_for_each_entry_safe(dev, tmp, &c->devices, list)
            if (dev->lct_data.tid == tid) {
            evt->i2o_dev = dev;
            break;
        }

        INIT_WORK(&evt->work, drv->event);
        queue_work(drv->event_queue, &evt->work);
        return 1;
    }

    if (unlikely(!drv->reply)) {
        osm_debug("%s: Reply to driver %s, but no reply function"
              " defined!\n", c->name, drv->name);
        return -EIO;
    }

    return drv->reply(c, m, msg);
}

void i2o_driver_notify_controller_add_all(struct i2o_controller *c)
{
    int i;
    struct i2o_driver *drv;

    for (i = 0; i < i2o_max_drivers; i++) {
        drv = i2o_drivers[i];

        if (drv)
            i2o_driver_notify_controller_add(drv, c);
    }
}

void i2o_driver_notify_controller_remove_all(struct i2o_controller *c)
{
    int i;
    struct i2o_driver *drv;

    for (i = 0; i < i2o_max_drivers; i++) {
        drv = i2o_drivers[i];

        if (drv)
            i2o_driver_notify_controller_remove(drv, c);
    }
}

void i2o_driver_notify_device_add_all(struct i2o_device *i2o_dev)
{
    int i;
    struct i2o_driver *drv;

    for (i = 0; i < i2o_max_drivers; i++) {
        drv = i2o_drivers[i];

        if (drv)
            i2o_driver_notify_device_add(drv, i2o_dev);
    }
}

void i2o_driver_notify_device_remove_all(struct i2o_device *i2o_dev)
{
    int i;
    struct i2o_driver *drv;

    for (i = 0; i < i2o_max_drivers; i++) {
        drv = i2o_drivers[i];

        if (drv)
            i2o_driver_notify_device_remove(drv, i2o_dev);
    }
}

int __init i2o_driver_init(void)
{
    int rc = 0;

    spin_lock_init(&i2o_drivers_lock);

    if ((i2o_max_drivers < 2) || (i2o_max_drivers > 64)) {
        osm_warn("max_drivers set to %d, but must be >=2 and <= 64\n",
             i2o_max_drivers);
        i2o_max_drivers = I2O_MAX_DRIVERS;
    }
    osm_info("max drivers = %d\n", i2o_max_drivers);

    i2o_drivers =
        kcalloc(i2o_max_drivers, sizeof(*i2o_drivers), GFP_KERNEL);
    if (!i2o_drivers)
        return -ENOMEM;

    rc = bus_register(&i2o_bus_type);

    if (rc < 0)
        kfree(i2o_drivers);

    return rc;
};

void i2o_driver_exit(void)
{
    bus_unregister(&i2o_bus_type);
    kfree(i2o_drivers);
};

EXPORT_SYMBOL(i2o_driver_register);
EXPORT_SYMBOL(i2o_driver_unregister);
EXPORT_SYMBOL(i2o_driver_notify_controller_add_all);
EXPORT_SYMBOL(i2o_driver_notify_controller_remove_all);
EXPORT_SYMBOL(i2o_driver_notify_device_add_all);
EXPORT_SYMBOL(i2o_driver_notify_device_remove_all);