/*
   * 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 <amax@us.ibm.com>

   *
   */

  #include <linux/sched.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
  ", 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
  ", 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
  ", __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);
  	}
  }

  /**
   * exec_command
   * send a command to a service processor
   * Commands are executed sequentially. One command (sp->current_command)
   * is sent to the service processor. Once the interrupt handler gets a
   * message of type command_response, the message is copied into

   * the current commands buffer,

   */
  void ibmasm_exec_command(struct service_processor *sp, struct command *cmd)
  {
  	unsigned long flags;

  	char tsbuf[32];

  	dbg("%s:%d at %s
  ", __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
  ", __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);
  	}
  }

  /**

   * Sleep until a command has failed or a response has been received
   * and the command status been updated by the interrupt handler.
   * (see receive_response).
   */
  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);
  }
  
  /**
   * receive_command_response
   * called by the interrupt handler when a dot command of type command_response
   * was received.
   */
  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);
  }