path: root/drivers/message/i2o/iop.c

/*
 *	Functions to handle I2O controllers and I2O message handling
 *
 *	Copyright (C) 1999-2002	Red Hat Software
 *
 *	Written by Alan Cox, Building Number Three Ltd
 *
 *	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.
 *
 *	A lot of the I2O message side code from this is taken from the
 *	Red Creek RCPCI45 adapter driver by Red Creek Communications
 *
 *	Fixes/additions:
 *		Philipp Rumpf
 *		Juha Siev�nen <Juha.Sievanen@cs.Helsinki.FI>
 *		Auvo H�kkinen <Auvo.Hakkinen@cs.Helsinki.FI>
 *		Deepak Saxena <deepak@plexity.net>
 *		Boji T Kannanthanam <boji.t.kannanthanam@intel.com>
 *		Alan Cox <alan@redhat.com>:
 *			Ported to Linux 2.5.
 *		Markus Lidel <Markus.Lidel@shadowconnect.com>:
 *			Minor fixes for 2.6.
 */

#include <linux/module.h>
#include <linux/i2o.h>
#include <linux/delay.h>
#include <linux/sched.h>
#include "core.h"

#define OSM_NAME	"i2o"
#define OSM_VERSION	"1.325"
#define OSM_DESCRIPTION	"I2O subsystem"

/* global I2O controller list */
LIST_HEAD(i2o_controllers);

/*
 * global I2O System Table. Contains information about all the IOPs in the
 * system. Used to inform IOPs about each others existence.
 */
static struct i2o_dma i2o_systab;

static int i2o_hrt_get(struct i2o_controller *c);

/**
 *	i2o_msg_get_wait - obtain an I2O message from the IOP
 *	@c: I2O controller
 *	@msg: pointer to a I2O message pointer
 *	@wait: how long to wait until timeout
 *
 *	This function waits up to wait seconds for a message slot to be
 *	available.
 *
 *	On a success the message is returned and the pointer to the message is
 *	set in msg. The returned message is the physical page frame offset
 *	address from the read port (see the i2o spec). If no message is
 *	available returns I2O_QUEUE_EMPTY and msg is leaved untouched.
 */
struct i2o_message *i2o_msg_get_wait(struct i2o_controller *c, int wait)
{
	unsigned long timeout = jiffies + wait * HZ;
	struct i2o_message *msg;

	while (IS_ERR(msg = i2o_msg_get(c))) {
		if (time_after(jiffies, timeout)) {
			osm_debug("%s: Timeout waiting for message frame.\n",
				  c->name);
			return ERR_PTR(-ETIMEDOUT);
		}
		schedule_timeout_uninterruptible(1);
	}

	return msg;
};

#if BITS_PER_LONG == 64
/**
 *      i2o_cntxt_list_add - Append a pointer to context list and return a id
 *	@c: controller to which the context list belong
 *	@ptr: pointer to add to the context list
 *
 *	Because the context field in I2O is only 32-bit large, on 64-bit the
 *	pointer is to large to fit in the context field. The i2o_cntxt_list
 *	functions therefore map pointers to context fields.
 *
 *	Returns context id > 0 on success or 0 on failure.
 */
u32 i2o_cntxt_list_add(struct i2o_controller * c, void *ptr)
{
	struct i2o_context_list_element *entry;
	unsigned long flags;

	if (!ptr)
		osm_err("%s: couldn't add NULL pointer to context list!\n",
			c->name);

	entry = kmalloc(sizeof(*entry), GFP_ATOMIC);
	if (!entry) {
		osm_err("%s: Could not allocate memory for context list element"
			"\n", c->name);
		return 0;
	}

	entry->ptr = ptr;
	entry->timestamp = jiffies;
	INIT_LIST_HEAD(&entry->list);

	spin_lock_irqsave(&c->context_list_lock, flags);

	if (unlikely(atomic_inc_and_test(&c->context_list_counter)))
		atomic_inc(&c->context_list_counter);

	entry->context = atomic_read(&c->context_list_counter);

	list_add(&entry->list, &c->context_list);

	spin_unlock_irqrestore(&c->context_list_lock, flags);

	osm_debug("%s: Add context to list %p -> %d\n", c->name, ptr, context);

	return entry->context;
};