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#ident "$Id: cpuid.c,v 1.1.1.1 2004-04-15 01:36:42 phoenix Exp $"

/* ----------------------------------------------------------------------- *

 *

 *   Copyright 2000 H. Peter Anvin - All Rights Reserved

 *

 *   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, Inc., 675 Mass Ave, Cambridge MA 02139,

 *   USA; either version 2 of the License, or (at your option) any later

 *   version; incorporated herein by reference.

 *

 * ----------------------------------------------------------------------- */

/*

 * cpuid.c

 *

 * x86 CPUID access device

 *

 * This device is accessed by lseek() to the appropriate CPUID level

 * and then read in chunks of 16 bytes.  A larger size means multiple

 * reads of consecutive levels.

 *

 * This driver uses /dev/cpu/%d/cpuid where %d is the minor number, and on

 * an SMP box will direct the access to CPU %d.

 */

#include <linux/module.h>

#include <linux/config.h>

#include <linux/types.h>

#include <linux/errno.h>

#include <linux/fcntl.h>

#include <linux/init.h>

#include <linux/poll.h>

#include <linux/smp.h>

#include <linux/major.h>

#include <asm/processor.h>

#include <asm/msr.h>

#include <asm/uaccess.h>

#include <asm/system.h>

#ifdef CONFIG_SMP

struct cpuid_command {

  int cpu;

  u32 reg;

  u32 *data;

};

static void cpuid_smp_cpuid(void *cmd_block)

{

  struct cpuid_command *cmd = (struct cpuid_command *) cmd_block;

  if ( cmd->cpu == smp_processor_id() )

    cpuid(cmd->reg, &cmd->data[0], &cmd->data[1], &cmd->data[2], &cmd->data[3]);

}

static inline void do_cpuid(int cpu, u32 reg, u32 *data)

{

  struct cpuid_command cmd;

  if ( cpu == smp_processor_id() ) {

    cpuid(reg, &data[0], &data[1], &data[2], &data[3]);

  } else {

    cmd.cpu  = cpu;

    cmd.reg  = reg;

    cmd.data = data;

    smp_call_function(cpuid_smp_cpuid, &cmd, 1, 1);

  }

}

#else /* ! CONFIG_SMP */

static inline void do_cpuid(int cpu, u32 reg, u32 *data)

{

  cpuid(reg, &data[0], &data[1], &data[2], &data[3]);

}

#endif /* ! CONFIG_SMP */

static loff_t cpuid_seek(struct file *file, loff_t offset, int orig)

{

  switch (orig) {

  case 0:

    file->f_pos = offset;

    return file->f_pos;

  case 1:

    file->f_pos += offset;

    return file->f_pos;

  default:

    return -EINVAL;     /* SEEK_END not supported */

  }

}

static ssize_t cpuid_read(struct file * file, char * buf,

                        size_t count, loff_t *ppos)

{

  u32 *tmp = (u32 *)buf;

  u32 data[4];

  size_t rv;

  u32 reg = *ppos;

  int cpu = MINOR(file->f_dentry->d_inode->i_rdev);

  if ( count % 16 )

    return -EINVAL; /* Invalid chunk size */

  for ( rv = 0 ; count ; count -= 16 ) {

    do_cpuid(cpu, reg, data);

    if ( copy_to_user(tmp,&data,16) )

      return -EFAULT;

    tmp += 4;

    *ppos = reg++;

  }

  return ((char *)tmp) - buf;

}

static int cpuid_open(struct inode *inode, struct file *file)

{

  int cpu = MINOR(file->f_dentry->d_inode->i_rdev);

  struct cpuinfo_x86 *c = &(cpu_data)[cpu];

  if ( !(cpu_online_map & (1UL << cpu)) )

    return -ENXIO;              /* No such CPU */

  if ( c->cpuid_level < 0 )

    return -EIO;                /* CPUID not supported */

  return 0;

}

/*

 * File operations we support

 */

static struct file_operations cpuid_fops = {

  owner:        THIS_MODULE,

  llseek:       cpuid_seek,

  read:         cpuid_read,

  open:         cpuid_open,

};

int __init cpuid_init(void)

{

  if (register_chrdev(CPUID_MAJOR, "cpu/cpuid", &cpuid_fops)) {

    printk(KERN_ERR "cpuid: unable to get major %d for cpuid\n",

           CPUID_MAJOR);

    return -EBUSY;

  }

  return 0;

}

void __exit cpuid_exit(void)

{

  unregister_chrdev(CPUID_MAJOR, "cpu/cpuid");

}

module_init(cpuid_init);

module_exit(cpuid_exit)

EXPORT_NO_SYMBOLS;

MODULE_AUTHOR("H. Peter Anvin <hpa@zytor.com>");

MODULE_DESCRIPTION("x86 generic CPUID driver");

MODULE_LICENSE("GPL");