/*
 * cpcihp_generic.c
 *
 * Generic port I/O CompactPCI driver
 *
 * Copyright 2002 SOMA Networks, Inc.
 * Copyright 2001 Intel San Luis Obispo
 * Copyright 2000,2001 MontaVista Software Inc.
 *
 * 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 SOFTWARE IS PROVIDED "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY 
 * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL 
 * THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF 
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING 
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS 
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * 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.
 *
 * This generic CompactPCI hotplug driver should allow using the PCI hotplug
 * mechanism on any CompactPCI board that exposes the #ENUM signal as a bit
 * in a system register that can be read through standard port I/O.
 *
 * Send feedback to <scottm@somanetworks.com>
 */

#include <linux/config.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/errno.h>
#include <linux/pci.h>
#include "cpci_hotplug.h"

#define DRIVER_VERSION	"0.1"
#define DRIVER_AUTHOR	"Scott Murray <scottm@somanetworks.com>"
#define DRIVER_DESC	"Generic port I/O CompactPCI Hot Plug Driver"

#if !defined(CONFIG_HOTPLUG_CPCI_GENERIC_MODULE)
#define MY_NAME	"cpcihp_generic"
#else
#define MY_NAME	THIS_MODULE->name
#endif

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

/* local variables */
static int debug;
static char* bridge;
static u8 bridge_busnr;
static u8 bridge_slot;
static struct pci_bus *bus;
static u8 first_slot;
static u8 last_slot;
static u16 port;
static unsigned int enum_bit;
static u8 enum_mask;

static struct cpci_hp_controller_ops generic_hpc_ops;
static struct cpci_hp_controller generic_hpc;

/* The following allows configuring the driver when it's compiled into the kernel */
#ifndef MODULE
static int __init cpcihp_generic_setup(char* str)
{
	char* p;
	unsigned long tmp;

	if(!str)
		return -EINVAL;
	bridge = str;

	p = strchr(str, ',');
	str = p + 1;
	if(!(p && *str && *p == ','))
		goto setup_error;
	tmp = simple_strtoul(str, &p, 0);
	if(p == str || tmp > 0xff) {
		err("hotplug bus first slot number out of range");
		goto setup_error;
	}
	first_slot = (u8) tmp;

	str = p + 1;		
	if(!(*str && *p == ','))
		return -EINVAL;
	tmp = simple_strtoul(str, &p, 0);
	if(p == str || tmp > 0xff) {
		err("hotplug bus last slot number out of range");
		goto setup_error;
	}
	last_slot = (u8) tmp;

	str = p + 1;
	if(!(*str && *p == ','))
		goto setup_error;
	tmp = simple_strtoul(str, &p, 0);
	if(p == str || tmp > 0xffff) {
		err("port number out of range");
		goto setup_error;
	}
	port = (u16) tmp;

	str = p + 1;
	if(!(*str && *p == ','))
		goto setup_error;
	tmp = simple_strtoul(str, &p, 0);
	if(p == str) {
		err("invalid #ENUM bit number");
		goto setup_error;
	}
	enum_bit = (u8) tmp;

	str = p + 1;
	if(*str && *p == ',') {
		tmp = simple_strtoul(str, &p, 0);
		if(p != str)
			debug = (int) tmp;
	}
	return 0;
setup_error:
	bridge = NULL;
	return -EINVAL;
}

__setup("cpcihp_generic=", cpcihp_generic_setup);
#endif

static int __init validate_parameters(void)
{
	char* str;
	char* p;
	unsigned long tmp;

	if(!bridge) {
		info("not configured, disabling.");
		return 1;
	}
	str = bridge;
	if(!*str)
		return -EINVAL;

	tmp = simple_strtoul(str, &p, 16);
	if(p == str || tmp > 0xff) {
		err("Invalid hotplug bus bridge device bus number");
		return -EINVAL;
	}
	bridge_busnr = (u8) tmp;
	dbg("bridge_busnr = 0x%02x", bridge_busnr);
	if(*p != ':') {
		err("Invalid hotplug bus bridge device");
		return -EINVAL;
	}
	str = p + 1;
	tmp = simple_strtoul(str, &p, 16);
	if(p == str || tmp > 0x1f) {
		err("Invalid hotplug bus bridge device slot number");
		return -EINVAL;
	}
	bridge_slot = (u8) tmp;
	dbg("bridge_slot = 0x%02x", bridge_slot);

	dbg("first_slot = 0x%02x", first_slot);
	dbg("last_slot = 0x%02x", last_slot);
	if(!(first_slot && last_slot)) {
		err("Need to specify first_slot and last_slot");
		return -EINVAL;
	}
	if(last_slot < first_slot) {
		err("first_slot must be less than last_slot");
		return -EINVAL;
	}

	dbg("port = 0x%04x", port);
	dbg("enum_bit = 0x%02x", enum_bit);
	if(enum_bit > 7) {
		err("Invalid #ENUM bit");
		return -EINVAL;
	}
	enum_mask = 1 << enum_bit;
	return 0;
}

static int query_enum(void)
{
	u8 value;

	value = inb_p(port);
	return ((value & enum_mask) == enum_mask);
}

static int __init cpcihp_generic_init(void)
{
	int status;
	struct resource* r;
	struct pci_dev* dev;

	info(DRIVER_DESC " version: " DRIVER_VERSION);
	status = validate_parameters();
	if(status != 0)
		return status;

	r = request_region(port, 1, "#ENUM hotswap signal register");
	if(!r)
		return -EBUSY;

	dev = pci_find_slot(bridge_busnr, PCI_DEVFN(bridge_slot, 0));
	if(!dev || dev->hdr_type != PCI_HEADER_TYPE_BRIDGE) {
		err("Invalid bridge device %s", bridge);
		return -EINVAL;
	}
	bus = dev->subordinate;

	memset(&generic_hpc, 0, sizeof (struct cpci_hp_controller));
	generic_hpc_ops.query_enum = query_enum;
	generic_hpc.ops = &generic_hpc_ops;

	status = cpci_hp_register_controller(&generic_hpc);
	if(status != 0) {
		err("Could not register cPCI hotplug controller");
		return -ENODEV;
	}
	dbg("registered controller");

	status = cpci_hp_register_bus(bus, first_slot, last_slot);
	if(status != 0) {
		err("Could not register cPCI hotplug bus");
		goto init_bus_register_error;
	}
	dbg("registered bus");

	status = cpci_hp_start();
	if(status != 0) {
		err("Could not started cPCI hotplug system");
		goto init_start_error;
	}
	dbg("started cpci hp system");
	return 0;
init_start_error:
	cpci_hp_unregister_bus(bus);
init_bus_register_error:
	cpci_hp_unregister_controller(&generic_hpc);
	err("status = %d", status);
	return status;

}

static void __exit cpcihp_generic_exit(void)
{
	cpci_hp_stop();
	cpci_hp_unregister_bus(bus);
	cpci_hp_unregister_controller(&generic_hpc);
	release_region(port, 1);
}

module_init(cpcihp_generic_init);
module_exit(cpcihp_generic_exit);

MODULE_AUTHOR(DRIVER_AUTHOR);
MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_LICENSE("GPL");
MODULE_PARM(debug, "i");
MODULE_PARM_DESC(debug, "Debugging mode enabled or not");
MODULE_PARM(bridge, "s");
MODULE_PARM_DESC(bridge, "Hotswap bus bridge device, <bus>:<slot> (bus and slot are in hexadecimal)");
MODULE_PARM(first_slot, "b");
MODULE_PARM_DESC(first_slot, "Hotswap bus first slot number");
MODULE_PARM(last_slot, "b");
MODULE_PARM_DESC(last_slot, "Hotswap bus last slot number");
MODULE_PARM(port, "h");
MODULE_PARM_DESC(port, "#ENUM signal I/O port");
MODULE_PARM(enum_bit, "i");
MODULE_PARM_DESC(enum_bit, "#ENUM signal bit (0-7)");