root/lm-sensors/trunk/prog/hotplug/p4b_smbus.c @ 1503

/*
 * p4b_smbus.c
 *
 * Initialize the I801SMBus device on ASUS P4B Bords
 */
/*
    Copyright (c) 2002 Ilja Rauhut <IljaRauhut@web.de> and
    Klaus Woltereck <kw42@gmx.net>,

    Based on the m7101.c hotplug example by:

    Copyright (c) 2000 Burkhard Kohl <buk@buks.ipn.de>,
    Frank Bauer <frank.bauer@nikocity.de>, and
    Mark D. Studebaker <mdsxyz123@yahoo.com>

    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., 675 Mass Ave, Cambridge, MA 02139, USA.
 */
/* CHANGES:
 * February 13,2002 IR First Version
 *
 * This code is absolutely experimental - use it at your own 
 * risk. 
 *
 * Warning, this module will work only with 2.4.x kernels.
 * If it works with earlier kernels then it is by luck.
 *
 * Warning, this module does not work with egcs < 2.95.2, use 
 * gcc > 2.7.2 or egcs >= 2.95.2. 
 *
 *
 * June 21, 2002, added support for the ICH4, code clean up -- Klaus
 */


#ifdef P4Bsmbus_DEBUG
#define DBG(x...) printk(x)
#else
#define DBG(x...)
#endif

#ifndef TRUE
#define TRUE 1
#define FALSE !TRUE
#endif

#include <linux/config.h>
#ifndef CONFIG_HOTPLUG
#error ERROR - You must have 'Support for hot-pluggable devices' enabled in your kernel (under 'general setup')!!
#endif

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/pci.h>
#include <linux/stddef.h>
#include <linux/ioport.h>
#include <linux/errno.h>
#include <linux/slab.h>
#include <linux/interrupt.h>
#include <asm/types.h>

#include <linux/sched.h> 
#include <linux/signal.h> 
#include <asm/irq.h>

/* 
rmm    from lm_sensors-2.3.3: 
 */

#define SMB_IO_SIZE  0xF
#define SMB_BASE 0x20


/*
 * some shorter definitions for the ICHx PCI device IDs
 */

#define ICH2 0x2440
#define ICH2_SMBUS 0x2443

#define ICH4 0x24c0
#define ICH4_SMBUS 0x24c3

/* status, used to indicate that io space needs to be freed */
static struct pci_dev *i801smbus = NULL;
static int i801smbus_inserted = FALSE;
extern void cleanup_module(void);
 
static rwlock_t i801smbus_lock = RW_LOCK_UNLOCKED;
static unsigned long i801smbus_lock_flags = 0;

/* 
 * Checks whether SMBus is enabled and turns it on in case they are not. 
 * It's done by clearing Bit 8 and 4 in i801 config space F2h, PCI-Device 0x8086:0x2440(ICH2)/0x24c0(ICH4)
 */
static int
i801smbus_enable(struct pci_dev *dev){
        u16  val   = 0;

        pci_read_config_word(dev, 0xF2, &val);
        DBG("i801smbus: i801smbus config byte reading 0x%X.\n", val);
        if (val & 0x008) {
                pci_write_config_word(dev, 0xF2, val & 0x77);
                pci_read_config_word(dev, 0xF2, &val);
                if(val & 0x008) 
                  {
                    DBG("i801smbus: i801smbus config byte locked:-(\n");
                    return -EIO;
                  }
                else
                  printk("i801smbus: SMBus activated in LPC!\n");
        }
        return 0;

}

/*
 * Builds the basic pci_dev for the i801smbus
 */
static int i801smbus_build(struct pci_dev **i801smbus, struct pci_bus *bus) 
{
        u32 devfn;
        u16 id = 0;
        u16 vid = 0;
        int ret;

        DBG("i801smbus: requesting kernel space for the i801smbus entry.\n");
        *i801smbus = kmalloc(sizeof(**i801smbus), GFP_ATOMIC);
        if(NULL == *i801smbus) {
                printk("i801smbus: out of memory.\n");
                return -ENOMEM;
        }

        /* minimally fill in structure for search */
        /* The device should be on the same bus as the i801. */
        memset(*i801smbus, 0, sizeof(**i801smbus));
        (*i801smbus)->bus    = bus;
        (*i801smbus)->sysdata = bus->sysdata;
        (*i801smbus)->hdr_type = PCI_HEADER_TYPE_NORMAL;

        DBG("i801smbus: now looking for i801smbus.\n");
        for  (id = 0, devfn = 0; devfn < 0xFF; devfn++) {
                (*i801smbus)->devfn = devfn;
                ret = pci_read_config_word(*i801smbus, PCI_DEVICE_ID, &id);
                if (ret == 0 && (ICH2_SMBUS == id || ICH4_SMBUS == id)) {
                        pci_read_config_word(*i801smbus, PCI_VENDOR_ID, &vid);
                        if(vid == 0x8086)
                                break;
                }
        }
        if (!(ICH2_SMBUS == id || ICH4_SMBUS == id)) {  
                DBG("i801smbus: i801smbus not found although i801 present - strange.\n");
                return -EACCES;
        } else {
                DBG("i801smbus: i801smbus found and enabled. Devfn: 0x%X.\n", devfn);
        }
        /* We now have the devfn and bus of the i801smbus device. 
         * let's put the rest of the device data together.
         */

        (*i801smbus)->vendor = 0x8086;
        (*i801smbus)->hdr_type = PCI_HEADER_TYPE_NORMAL;
        (*i801smbus)->device = id;
 
        return(pci_setup_device(*i801smbus));
}




/* Initialize the module */
int init_module(void)
{
        struct pci_bus *bus = NULL;
        struct pci_dev *dev = NULL;
        int ret = 0;

        DBG("i801smbus: init_module().\n");

        /* Are we on a PCI-Board? */
        if (!pci_present()) {
                printk("i801smbus: No PCI bus found - sorry.\n");
                return -ENODEV;
        }

        /* We want to be sure that the i801smbus is not present yet. */
        dev = pci_find_device(0x8086, ICH2_SMBUS, NULL);

        if (dev) 
          {
            printk("i801smbus: SMBus already active\n");
            return -EPERM;
          }
        
        dev = pci_find_device(0x8086, ICH4_SMBUS, NULL);

        if (dev) 
          {
            printk("i801smbus: SMBus already active\n");
            return -EPERM;
          }
        
        /* Are we operating a i801 chipset */
        dev = pci_find_device(0x8086, ICH2, NULL);
        if (NULL == dev) 
          {
            dev = pci_find_device(0x8086, ICH4, NULL);
            if (NULL == dev) 
              {
                printk("i801smbus: INTEL ICH2/4 (82801AB/DB) not found.\n");
                return -ENODEV ;
              }
            else
              {
                printk("i801smbus: found Intel ICH4 (82801DB).\n");
              }
          }
        else
          {
            printk("i801smbus: found Intel ICH2 (82801AB).\n");
          }

        /* we need the bus pointer later */
        bus = dev->bus;


        if ( (ret = i801smbus_enable(dev)) ) 
          {
            printk("i801smbus: Unable to turn on i801smbus device - sorry!\n");
            return ret;
          }
     
        if ( (ret = i801smbus_build(&i801smbus, bus)) )
                return ret;


        if ( (ret = pci_enable_device(i801smbus)) ) {
                printk("i801smbus: Unable to pci_enable i801smbus device!\n");
                return ret;
        }
    
        DBG("i801smbus: now inserting.\n");
        pci_insert_device(i801smbus, i801smbus->bus);
        printk("i801smbus: Enabled\n");
        i801smbus_inserted = TRUE;
        return 0;
}


void cleanup_module(void)
{
        write_lock_irqsave(i801smbus_lock, i801smbus_lock_flags);
        if (i801smbus_inserted) {
                pci_remove_device(i801smbus);
                i801smbus_inserted = FALSE;
        }
        write_unlock_irqrestore(i801smbus_lock, i801smbus_lock_flags);

        if (NULL != i801smbus)
          {
            kfree(i801smbus);
          }
        printk("i801smbus: SMBus device removed\n");
}

EXPORT_NO_SYMBOLS;

#ifdef MODULE
#ifdef MODULE_LICENSE
MODULE_LICENSE("GPL");
#endif
MODULE_AUTHOR("Ilja Rauhut <IljaRauhut@web.de>, "
              "Burkhard Kohl <bku@buks.ipn.de>, "
              "Frank Bauer <frank.bauer@nikocity.de>, "
              "Mark Studebaker <mdsxyz123@yahoo.com>,"
              "and Klaus Woltereck <kw42@gmx.net>");
MODULE_DESCRIPTION("i801smbus PCI Inserter");

#endif                          /* MODULE */