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/*

 * Project: S.Ha.R.K.

 *

 * Coordinators:

 *   Giorgio Buttazzo    <giorgio@sssup.it>

 *   Paolo Gai           <pj@gandalf.sssup.it>

 *

 * Authors     :

 *   Paolo Gai           <pj@gandalf.sssup.it>

 *   Massimiliano Giorgi <massy@gandalf.sssup.it>

 *   Luca Abeni          <luca@gandalf.sssup.it>

 *   (see the web pages for full authors list)

 *

 * ReTiS Lab (Scuola Superiore S.Anna - Pisa - Italy)

 *

 * http://www.sssup.it

 * http://retis.sssup.it

 * http://shark.sssup.it

 */

/***************************************

  CVS :        $Id: bdev.c,v 1.2 2004-05-26 11:20:23 giacomo Exp $

  Revision:    $Revision: 1.2 $

  Last update: $Date: 2004-05-26 11:20:23 $

  This module contains the block device manager: it export some functions

  to the rest of the kernel that are mapped to a real device driver

  sub-system.

***************************************/

/*

 * Copyright (C) 1999 Massimiliano Giorgi

 *

 * 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

 *

 */

#include "glue.h"

#include <fs/bdevconf.h>

#include <fs/bdev.h>

#include <fs/magic.h>

#include <fs/assert.h>

#include <fs/sysmacro.h>

#include <fs/bdevinit.h>

#include <fs/fsind.h>

//#include <fs/mutex.h>

#include "bdev.h"

/*+ Log Level to use +*/

#define BDEVLOG KERN_ERR

/*+ an entry for every block device +*/

static struct block_device bdev[MAXBLOCKDEVICE];

/*+ an index into bdev_minor +*/

int bdev_minor_index=0;

/*+ an entry for every block device minor number +*/

struct block_device_minor bdev_minor[MAXBLOCKDEVICEMINOR];

/*+ some operations must be done in mutual exclusion +*/

NOP_mutexattr_t        bdevdef_mutexattr=NOP_MUTEXATTR_INITIALIZER;

__b_mutex_t            mutex;

void                   *bmutexattr=NULL;

static BDEV_PARMS      defaultparms=BASE_BDEV;

/*++++++++++++++++++++++++++++++++++++++

  Initialize the block device manager and then initialize every

  block-device sub-system defined into bdevconf.h (Actualy it is

  impossible to load a module at run-time).

  int bdev_init

    return 0 on success, other value on error

  BDEV_PARMS *parms

    pointer to a structure that contains all device inizialization parameter

  ++++++++++++++++++++++++++++++++++++++*/

int bdev_init(BDEV_PARMS *parms)

{

  int i;

  if (parms==NULL) parms=&defaultparms;

  /* 'bmutexattr' initialization */

  bmutexattr=parms->bmutexattr;

  if (bmutexattr==NULL) bmutexattr=&bdevdef_mutexattr;

  /* initialize mutex */

  __b_mutex_init(&mutex);

  /* initialize the bdev[] table */

  for (i=0;i<MAXBLOCKDEVICE;i++) {    

    magic_set(bdev[i].magic,BLOCK_DEVICE_MAGIC);    

    bdev[i].bd_flag_used=0;

  }

  /* initialize the bdev_minor[] table */

  /*for (i=0;i<MAX*/

#ifdef IDE_BLOCK_DEVICE

  /* if requested initialize the IDE subsystem */

  ide_init(parms);

#endif

#ifdef LOOP_BLOCK_DEVICE

  /* if requested initialize the "loop device" subsystem */

  loop_init(parms);

#endif

  return 0;

}

/*++++++++++++++++++++++++++++++++++++++

  Every block device sub-system must call this function yo register

  itself to the device block manager.

  int bdev_register

    return 0 on success, -1 on failure

  __dev_t devmajor

    major block device number to register

  char *name

    the name of the device (must be a pointer to static data)

  struct block_device *dev

    information to hook the block device routine

  ++++++++++++++++++++++++++++++++++++++*/

int bdev_register(__dev_t devmajor, char *name, struct block_device *dev)

{

  __dev_t mj=major(devmajor);

  /* check for consistency */

  if (mj<=0||mj>=MAXBLOCKDEVICE) {

    printk(BDEVLOG "bdev: request to register invalid major %i",

           mj);

    return -1;

  }

  if (bdev[mj].bd_flag_used) {

    printk(BDEVLOG "bdev: requet to register used major %i",

           mj);

    return -1;

  }

  magic_assert(bdev[mj].magic,BLOCK_DEVICE_MAGIC,

               "bdev: device(%i,%i) overwritten prior to use",

               mj,minor(devmajor));

  /* register the device */

  memcpy(bdev+mj,dev,sizeof(struct block_device));

  bdev[mj].bd_flag_used=1;

  bdev[mj].bd_name=name;

  magic_set(bdev[mj].magic,BLOCK_DEVICE_MAGIC);

  return 0;

}

static __uint8_t part2sysind(__uint8_t par_ind)

{

  switch(par_ind) {

    case FSPAR_DOS12:

    case FSPAR_DOS16:

    case FSPAR_DOSBIG:

      return FS_MSDOS;

    case FSPAR_LNXNTV:

      return FS_EXT2;

  }

  return FS_DEFAULT;

}

/*++++++++++++++++++++++++++++++++++++++

  Every block device sub-system must call this function to register

  itself to the device block manager (these information are used by

  the devfs filesystem to export device name to the system in a

  POSIX fanshion).

  int bdev_register_minor

    return a minor index on success, <0 on failure

  __dev_t device

    block device to register

  char *name

    the name of the device

  __uint8_t fsind

    file system indicator (see fsind.h)

  ++++++++++++++++++++++++++++++++++++++*/

int bdev_register_minor(__dev_t device, char *name,__uint8_t fsind)

{

  /* checks for bad requests */

  if (bdev_minor_index==MAXBLOCKDEVICEMINOR) return -1;

  if (major(device)>MAXBLOCKDEVICE) return -2;

  if (!bdev[major(device)].bd_flag_used) return -3;

  /* register minor device */

  strncpy(bdev_minor[bdev_minor_index].bdm_name,name,MAXDEVICENAME);

  bdev_minor[bdev_minor_index].bdm_name[MAXDEVICENAME-1]='\0';

  bdev_minor[bdev_minor_index].bdm_device=device;

  bdev_minor[bdev_minor_index].bdm_fsind=part2sysind(fsind);

  return bdev_minor_index++;

}

/*++++++++++++++++++++++++++++++++++++++

  Find a device using its name.

  __dev_t bdev_find_byname

    return a device number on success, <0 on failure

  char *name

    the name of the device to find

  ++++++++++++++++++++++++++++++++++++++*/

__dev_t bdev_find_byname(char *name)

{

  char *s0,*s1,*s2;

  char saved;

  int i;

  /*

   * a name can be, for example, "/dev/ide/hda1";

   * after this code s0 is a pointer to "ide" (the major name) and s1 is

   * a pointer to "hda1" (the minor name)

   */

  s0=name;  

  s1=strchr(name,'/');

  if (s1==NULL) return -1;

  while ((s2=strchr(s1+1,'/'))!=NULL) {

    s0=s1+1;

    s1=s2;

  }

  saved=*s1;

  *s1++='\0';

  /* search for a device... */

  for (i=0;i<bdev_minor_index;i++)

    /* compare a minor name */

    if (!strcmp(s1,bdev_minor[i].bdm_name))

      /* compare a major name */

      if (!strcmp(bdev[major(bdev_minor[i].bdm_device)].bd_name,s0)) {

        *(s1-1)=saved;

        return bdev_minor[i].bdm_device;

      }

  *(s1-1)=saved;

  return -2;

}

/*++++++++++++++++++++++++++++++++++++++

  Find major and minor name using a device id (__dev_t).

  int bdev_findname

    return 0 on success; -1 on failure.

  __dev_t dev

    device identification

  char **major

    the major name is pointed here

  char **minor

    the minor name is pointed here

  ++++++++++++++++++++++++++++++++++++++*/

int bdev_findname(__dev_t dev, char **major,char **minor)

{

  int i;

  assertk(major!=NULL&&minor!=NULL);

  for (i=0;i<bdev_minor_index;i++)

    if (bdev_minor[i].bdm_device==dev) {

      *minor=bdev_minor[i].bdm_name;

      *major=bdev[major(dev)].bd_name;

      return 0;

    }

  return -1;

}

/*++++++++++++++++++++++++++++++++++++++

  Find a device using its file system indicator (the first device

  that use this file system).

  __dev_t bdev_find_byfs

    return a device number on success, <0 on failure

  __uint8_t fsind

    file system indicator

  ++++++++++++++++++++++++++++++++++++++*/

__dev_t bdev_find_byfs(__uint8_t fsind)

{

  int i;

  for (i=0;i<bdev_minor_index;i++)

    if (bdev_minor[i].bdm_fsind==fsind)

      return bdev_minor[i].bdm_device;         

  return -1;

}

/*++++++++++++++++++++++++++++++++++++++

  Scan all devices into the system: for every device found call

  the callback function, if it returns -1 continue scanning else

  the values passed is returned.

  __dev_t bdev_find_byfs

    return a device number on success, <0 on failure

  __uint8_t fsind

    file system indicator

  ++++++++++++++++++++++++++++++++++++++*/

int bdev_scan_devices(int(*callback)(__dev_t,__uint8_t))

{

  int res=0;

  int i;

  for (i=0;i<bdev_minor_index;i++) {

    res=callback(bdev_minor[i].bdm_device,

                 bdev_minor[i].bdm_fsind

                 );

    if (res!=-1) break;

  }

  return res;

}

//#ifndef NDEBUG

#include <fs/major.h>

extern int ide_dump_startsize(__dev_t, __blkcnt_t*, __blkcnt_t*);

extern void ide_dump_status(void);

void bdev_dump_names(void)

{

  int i;

  __blkcnt_t start,size;

  printk(KERN_INFO "block device names:");

  for (i=0;i<bdev_minor_index;i++) {

    start=size=0;

    if (major(bdev_minor[i].bdm_device)==MAJOR_B_IDE)

      ide_dump_startsize(bdev_minor[i].bdm_device,&start,&size);

    printk(KERN_INFO "    %s/%8s   %08x (start-%-8li size-%-8li sysind-%02x)",

           bdev[major(bdev_minor[i].bdm_device)].bd_name,

           bdev_minor[i].bdm_name,

           bdev_minor[i].bdm_device,

           (long int)start,(long int)size,

           bdev_minor[i].bdm_fsind         

           );

  }

}

void bdev_dump_status(void)

{

  int counter,i;

  printk(KERN_INFO "block device status:");

  printk(KERN_INFO "  registered devices:");

  for (counter=0,i=0;i<MAXBLOCKDEVICE;i++)

    if (bdev[i].bd_flag_used) {

      printk(KERN_INFO "    %s",bdev[i].bd_name);

      counter++;

    }  

  printk(KERN_INFO "  num. majors: %i",counter);

  printk(KERN_INFO "  num. minors: %i",bdev_minor_index);

#ifdef IDE_BLOCK_DEVICE

  ide_dump_status();

#endif

}

//#endif

/*++++++++++++++++++++++++++++++++++++++

  Try to lock a device.

  Locking a device means that the locking entity can do I/O on that

  device (no check is performed during I/O operations).

  int bdev_trylock

    return 1 on success, 0 on failure and, -1 on error

  __dev_t dev

    device to lock

  ++++++++++++++++++++++++++++++++++++++*/

int bdev_trylock(__dev_t dev)

{

  int res;

  magic_assert(bdev[major(dev)].magic,BLOCK_DEVICE_MAGIC,

               "bdev: device(%04x:%04x) overwritten",

               major(dev),minor(dev));

  if (!bdev[major(dev)].bd_flag_used) {

    printk(BDEVLOG "bdev: device(%04x:%04x) not registered",

           major(dev),minor(dev));       

    return -1;

  }

  __b_mutex_lock(&mutex);

  res=bdev[major(dev)].bd_op->_trylock(dev);

  __b_mutex_unlock(&mutex);

  return res;

}

/*++++++++++++++++++++++++++++++++++++++

  Try to unlock a device.

  int bdev_tryunlock

    return 1 on success, 0 on failure and, -1 on error

  __dev_t dev

    device to unlock

  ++++++++++++++++++++++++++++++++++++++*/

int bdev_tryunlock(__dev_t dev)

{

  int res;

  magic_assert(bdev[major(dev)].magic,BLOCK_DEVICE_MAGIC,

               "bdev: device(%04x:%04x) overwritten",

               major(dev),minor(dev));

  if (!bdev[major(dev)].bd_flag_used) {

    printk(BDEVLOG "bdev: device(%04x:%04x) not registered",

           major(dev),minor(dev));       

    return -1;

  }

  __b_mutex_lock(&mutex);

  res=bdev[major(dev)].bd_op->_tryunlock(dev);

  __b_mutex_unlock(&mutex);

  return res;

}

/*++++++++++++++++++++++++++++++++++++++

  The following function are used to "virtualize" the call of a function

  of a block device sub-system.

  Actually they are implemeted by function to perform some parameters

  check but they will be implemented by macro.

  +latex+ \\

  This function request to read a block number.

  int bdev_read

    return 0 on success, other value on error

  __dev_t dev

    device where to read from

  __blkcnt_t blocknum

    block number to read

  __uint8_t *buffer

    buffer for the readed data

  ++++++++++++++++++++++++++++++++++++++*/

int bdev_read(__dev_t dev, __blkcnt_t blocknum, __uint8_t *buffer)

{

  magic_assert(bdev[major(dev)].magic,BLOCK_DEVICE_MAGIC,

               "bdev: device(%04x:%04x) overwritten",

               major(dev),minor(dev));

  if (!bdev[major(dev)].bd_flag_used) {

    printk(BDEVLOG "bdev: device(%04x:%04x) not registered",

           major(dev),minor(dev));       

    return -1;

  }

  if (blocknum<0) {

    printk(BDEVLOG "bdev: device(%04x:%04x) read request out of range",

           major(dev),minor(dev));       

    return -1;

  }

  return bdev[major(dev)].bd_op->read(dev,blocknum,buffer);

}

/*++++++++++++++++++++++++++++++++++++++

  This function request to move the head to a specified block of a device.

  int bdev_seek

    return 0 on success, other value on error

  __dev_t dev

    device to seek

  __blkcnt_t blocknum

    block number to seek into

  ++++++++++++++++++++++++++++++++++++++*/

int bdev_seek(__dev_t dev, __blkcnt_t blocknum)

{

  magic_assert(bdev[major(dev)].magic,BLOCK_DEVICE_MAGIC,

               "bdev: device(%04x:%04x) overwritten",

               major(dev),minor(dev));

  if (!bdev[major(dev)].bd_flag_used) {

    printk(BDEVLOG "bdev: device(%04x:%04x) not registered",

           major(dev),minor(dev));       

    return -1;

  }

  if (blocknum<0) {

    printk(BDEVLOG "bdev: device(%04x:%04x) seek request out of range",

           major(dev),minor(dev));       

    return -1;

  }

  return bdev[major(dev)].bd_op->seek(dev,blocknum);

}

/*++++++++++++++++++++++++++++++++++++++

  Write a block into a device.

  int bdev_write

    return 0 on success, other value on error

  __dev_t dev

    device to write into

  __blkcnt_t blocknum

    block number to write

  __uint8_t *buffer

    buffer with data to write

  ++++++++++++++++++++++++++++++++++++++*/

int bdev_write(__dev_t dev, __blkcnt_t blocknum, __uint8_t *buffer)

{

  magic_assert(bdev[major(dev)].magic,BLOCK_DEVICE_MAGIC,              

               "bdev: device(%04x:%04x) overwritten",

               major(dev),minor(dev));

  if (!bdev[major(dev)].bd_flag_used) {

    printk(BDEVLOG "bdev: device(%04x:%04x) not registered",

           major(dev),minor(dev));       

    return -1;

  }

  if (blocknum<0) {

    printk(BDEVLOG "bdev: device(%04x:%04x) write request out of range",

           major(dev),minor(dev));       

    return -1;

  }

  return bdev[major(dev)].bd_op->write(dev,blocknum,buffer);

}