command.c

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/*
 * IBM ASM Service Processor Device Driver
 *
 * 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.  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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 *
 * Copyright (C) IBM Corporation, 2004
 *
 * Author: Max Asböck <[email protected]>
 *
 */

#include <linux/sched.h>
#include <linux/slab.h>
#include "ibmasm.h"
#include "lowlevel.h"

static void exec_next_command(struct service_processor *sp);

static atomic_t command_count = ATOMIC_INIT(0);

struct command *ibmasm_new_command(struct service_processor *sp, size_t buffer_size)
{
    struct command *cmd;

    if (buffer_size > IBMASM_CMD_MAX_BUFFER_SIZE)
        return NULL;

    cmd = kzalloc(sizeof(struct command), GFP_KERNEL);
    if (cmd == NULL)
        return NULL;


    cmd->buffer = kzalloc(buffer_size, GFP_KERNEL);
    if (cmd->buffer == NULL) {
        kfree(cmd);
        return NULL;
    }
    cmd->buffer_size = buffer_size;

    kref_init(&cmd->kref);
    cmd->lock = &sp->lock;

    cmd->status = IBMASM_CMD_PENDING;
    init_waitqueue_head(&cmd->wait);
    INIT_LIST_HEAD(&cmd->queue_node);

    atomic_inc(&command_count);
    dbg("command count: %d\n", atomic_read(&command_count));

    return cmd;
}

void ibmasm_free_command(struct kref *kref)
{
    struct command *cmd = to_command(kref);

    list_del(&cmd->queue_node);
    atomic_dec(&command_count);
    dbg("command count: %d\n", atomic_read(&command_count));
    kfree(cmd->buffer);
    kfree(cmd);
}

static void enqueue_command(struct service_processor *sp, struct command *cmd)
{
    list_add_tail(&cmd->queue_node, &sp->command_queue);
}

static struct command *dequeue_command(struct service_processor *sp)
{
    struct command *cmd;
    struct list_head *next;

    if (list_empty(&sp->command_queue))
        return NULL;

    next = sp->command_queue.next;
    list_del_init(next);
    cmd = list_entry(next, struct command, queue_node);

    return cmd;
}

static inline void do_exec_command(struct service_processor *sp)
{
    char tsbuf[32];

    dbg("%s:%d at %s\n", __func__, __LINE__, get_timestamp(tsbuf));

    if (ibmasm_send_i2o_message(sp)) {
        sp->current_command->status = IBMASM_CMD_FAILED;
        wake_up(&sp->current_command->wait);
        command_put(sp->current_command);
        exec_next_command(sp);
    }
}

void ibmasm_exec_command(struct service_processor *sp, struct command *cmd)
{
    unsigned long flags;
    char tsbuf[32];

    dbg("%s:%d at %s\n", __func__, __LINE__, get_timestamp(tsbuf));

    spin_lock_irqsave(&sp->lock, flags);

    if (!sp->current_command) {
        sp->current_command = cmd;
        command_get(sp->current_command);
        spin_unlock_irqrestore(&sp->lock, flags);
        do_exec_command(sp);
    } else {
        enqueue_command(sp, cmd);
        spin_unlock_irqrestore(&sp->lock, flags);
    }
}

static void exec_next_command(struct service_processor *sp)
{
    unsigned long flags;
    char tsbuf[32];

    dbg("%s:%d at %s\n", __func__, __LINE__, get_timestamp(tsbuf));

    spin_lock_irqsave(&sp->lock, flags);
    sp->current_command = dequeue_command(sp);
    if (sp->current_command) {
        command_get(sp->current_command);
        spin_unlock_irqrestore(&sp->lock, flags);
        do_exec_command(sp);
    } else {
        spin_unlock_irqrestore(&sp->lock, flags);
    }
}

void ibmasm_wait_for_response(struct command *cmd, int timeout)
{
    wait_event_interruptible_timeout(cmd->wait,
                cmd->status == IBMASM_CMD_COMPLETE ||
                cmd->status == IBMASM_CMD_FAILED,
                timeout * HZ);
}

void ibmasm_receive_command_response(struct service_processor *sp, void *response, size_t size)
{
    struct command *cmd = sp->current_command;

    if (!sp->current_command)
        return;

    memcpy_fromio(cmd->buffer, response, min(size, cmd->buffer_size));
    cmd->status = IBMASM_CMD_COMPLETE;
    wake_up(&sp->current_command->wait);
    command_put(sp->current_command);
    exec_next_command(sp);
}