Subversion Repositories openrisc_2011-10-31

/*  This file is part of the program psim.

    Copyright (C) 1994-1997, Andrew Cagney <cagney@highland.com.au>

    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.

    */

#ifndef _HW_DISK_C_

#define _HW_DISK_C_

#include "device_table.h"

#include "pk.h"

#include <stdio.h>

#ifdef HAVE_UNISTD_H

#include <unistd.h>

#endif

#ifndef SEEK_SET

#define SEEK_SET 0

#endif

/* DEVICE

   cdrom - read-only removable mass storage device

   disk - mass storage device

   floppy - removable mass storage device

   DESCRIPTION

   Mass storage devices such as a hard-disk or cdrom-drive are not

   normally directly connected to the processor.  Instead, these

   devices are attached to a logical bus, such as SCSI or IDE, and

   then a controller of that bus is made accessible to the processor.

   Reflecting this, within a device tree, mass storage devices such as

   a <<cdrom>>, <<disk>> or <<floppy>> are created as children of of a

   logical bus controller node (such as a SCSI or IDE interface).

   That controller, in turn, would be made the child of a physical bus

   node that is directly accessible to the processor.

   The above mass storage devices provide two interfaces - a logical

   and a physical.

   At the physical level the <<device_io_...>> functions can be used

   perform reads and writes of the raw media.  The address being

   interpreted as an offset from the start of the disk.

   At the logical level, it is possible to create an instance of the

   disk that provides access to any of the physical media, a disk

   partition, or even a file within a partition.  The <<disk-label>>

   package, which implements this functionality, is described

   elsewhere.  Both the Open Firmware and Moto BUG rom emulations

   support this interface.

   Block devices such as the <<floppy>> and <<cdrom>> have removable

   media.  At the programmer level, the media can be changed using the

   <<change_media>> ioctl.  From within GDB, a <<change-media>>

   operation can be initated by using the command.

   |    (gdb)  sim

   PROPERTIES

   file = <file-name>  (required)

   The name of the file that contains an image of the disk.  For

   <<disk>> and <<floppy>> devices, the image will be opened for both

   reading and writing.  Multiple image files may be specified, the

   second and later files being opened when <<change-media>> (with a

   NULL file name) being specified.

   block-size = <nr-bytes>  (optional)

   The value is returned by the block-size method.  The default value

   is 512 bytes.

   max-transfer = <nr-bytes>  (optional)

   The value is returned by the max-transfer method. The default value

   is 512 bytes.

   #blocks = <nr-blocks>  (optional)

   The value is returned by the #blocks method.  If no value is

   present then -1 is returned.

   read-only = <anything>  (optional)

   If this property is present, the disk file image is always opened

   read-only.

   EXAMPLES

   Enable tracing

   | $  psim -t 'disk-device' \

   Add a CDROM and disk to an IDE bus.  Specify the host operating

   system's cd drive as the CD-ROM image.

   |    -o '/pci/ide/disk@0/file "disk-image' \

   |    -o '/pci/ide/cdrom@1/file "/dev/cd0a' \

   As part of the code implementing a logical bus device (for instance

   the IDE controller), locate the CDROM device and then read block

   47.

   |  device *cdrom = device_tree_find_device(me, "cdrom");

   |  char block[512];

   |  device_io_read_buffer(cdrom, buf, 0,

                            0, 47 * sizeof(block), // space, address

                            sizeof(block), NULL, 0);

   Use the device instance interface to read block 47 of the file

   called <<netbsd.elf>> on the disks default partition.  Similar code

   would be used in an operating systems pre-boot loader.

   |  device_instance *netbsd =

   |    device_create_instance(root, "/pci/ide/disk:,\netbsd.elf");

   |  char block[512];

   |  device_instance_seek(netbsd,  0, 47 * sizeof(block));

   |  device_instance_read(netbsd, block, sizeof(block));

   BUGS

   The block device specification includes mechanisms for determining

   the physical device characteristics - such as the disks size.

   Currently this mechanism is not implemented.

   The functionality of this device (in particular the device instance

   interface) depends on the implementation of <<disk-label>> package.

   That package may not be fully implemented.

   The disk does not know its size.  Hence it relies on the failure of

   fread(), fwrite() and fseek() calls to detect errors.

   The disk size is limited by the addressable range covered by

   unsigned_word (addr).  An extension would be to instead use the

   concatenated value space:addr.

   The method #blocks should `stat' the disk to determine the number

   of blocks if there is no #blocks property.

   It would appear that OpenFirmware does not define a client call for

   changing (ejecting) the media of a device.

   */

typedef struct _hw_disk_device {

  int name_index;

  int nr_names;

  char *name;

  int read_only;

  /*  unsigned_word size; */

  FILE *image;

} hw_disk_device;

typedef struct _hw_disk_instance {

  unsigned_word pos;

  hw_disk_device *disk;

} hw_disk_instance;

static void

open_disk_image(device *me,

                hw_disk_device *disk,

                const char *name)

{

  if (disk->image != NULL)

    fclose(disk->image);

  if (disk->name != NULL)

    zfree(disk->name);

  disk->name = strdup(name);

  disk->image = fopen(disk->name, disk->read_only ? "r" : "r+");

  if (disk->image == NULL) {

    perror(device_name(me));

    device_error(me, "open %s failed\n", disk->name);

  }

  DTRACE(disk, ("image %s (%s)\n",

                disk->name,

                (disk->read_only ? "read-only" : "read-write")));

}

static void

hw_disk_init_address(device *me)

{

  hw_disk_device *disk = device_data(me);

  unsigned_word address;

  int space;

  const char *name;

  /* attach to the parent. Since the bus is logical, attach using just

     the unit-address (size must be zero) */

  device_address_to_attach_address(device_parent(me), device_unit_address(me),

                                   &space, &address, me);

  device_attach_address(device_parent(me), attach_callback,

                        space, address, 0/*size*/, access_read_write_exec,

                        me);

  /* Tell the world we are a disk.  */

  device_add_string_property(me, "device_type", "block");

  /* get the name of the file specifying the disk image */

  disk->name_index = 0;

  disk->nr_names = device_find_string_array_property(me, "file",

                                                     disk->name_index, &name);

  if (!disk->nr_names)

    device_error(me, "invalid file property");

  /* is it a RO device? */

  disk->read_only =

    (strcmp(device_name(me), "disk") != 0

     && strcmp(device_name(me), "floppy") != 0

     && device_find_property(me, "read-only") == NULL);

  /* now open it */

  open_disk_image(me, disk, name);

}

static int

hw_disk_ioctl(device *me,

              cpu *processor,

              unsigned_word cia,

              device_ioctl_request request,

              va_list ap)

{

  switch (request) {

  case device_ioctl_change_media:

    {

      hw_disk_device *disk = device_data(me);

      const char *name = va_arg(ap, const char *);

      if (name != NULL) {

        disk->name_index = -1;

      }

      else {

        disk->name_index = (disk->name_index + 1) % disk->nr_names;

        if (!device_find_string_array_property(me, "file",

                                               disk->name_index, &name))

          device_error(me, "invalid file property");

      }

      open_disk_image(me, disk, name);

    }

    break;

  default:

    device_error(me, "insupported ioctl request");

    break;

  }

  return 0;

}

static unsigned

hw_disk_io_read_buffer(device *me,

                       void *dest,

                       int space,

                       unsigned_word addr,

                       unsigned nr_bytes,

                       cpu *processor,

                       unsigned_word cia)

{

  hw_disk_device *disk = device_data(me);

  unsigned nr_bytes_read;

  if (space != 0)

    device_error(me, "read - extended disk addressing unimplemented");

  if (nr_bytes == 0)

    nr_bytes_read = 0;

  else if (fseek(disk->image, addr, SEEK_SET) < 0)

    nr_bytes_read = 0;

  else if (fread(dest, nr_bytes, 1, disk->image) != 1)

    nr_bytes_read = 0;

  else

    nr_bytes_read = nr_bytes;

  DTRACE(disk, ("io-read - address 0x%lx, nr-bytes-read %d, requested %d\n",

                (unsigned long) addr, (int)nr_bytes_read, (int)nr_bytes));

  return nr_bytes_read;

}

static unsigned

hw_disk_io_write_buffer(device *me,

                        const void *source,

                        int space,

                        unsigned_word addr,

                        unsigned nr_bytes,

                        cpu *processor,

                        unsigned_word cia)

{

  hw_disk_device *disk = device_data(me);

  unsigned nr_bytes_written;

  if (space != 0)

    device_error(me, "write - extended disk addressing unimplemented");

  if (disk->read_only)

    nr_bytes_written = 0;

  else if (nr_bytes == 0)

    nr_bytes_written = 0;

  else if (fseek(disk->image, addr, SEEK_SET) < 0)

    nr_bytes_written = 0;

  else if (fwrite(source, nr_bytes, 1, disk->image) != 1)

    nr_bytes_written = 0;

  else

    nr_bytes_written = nr_bytes;

  DTRACE(disk, ("io-write - address 0x%lx, nr-bytes-written %d, requested %d\n",

                (unsigned long) addr, (int)nr_bytes_written, (int)nr_bytes));

  return nr_bytes_written;

}

/* instances of the hw_disk device */

static void

hw_disk_instance_delete(device_instance *instance)

{

  hw_disk_instance *data = device_instance_data(instance);

  DITRACE(disk, ("delete - instance=%ld\n",

                 (unsigned long)device_instance_to_external(instance)));

  zfree(data);

}

static int

hw_disk_instance_read(device_instance *instance,

                      void *buf,

                      unsigned_word len)

{

  hw_disk_instance *data = device_instance_data(instance);

  DITRACE(disk, ("read - instance=%ld len=%ld\n",

                 (unsigned long)device_instance_to_external(instance),

                 (long)len));

  if ((data->pos + len) < data->pos)

    return -1; /* overflow */

  if (fseek(data->disk->image, data->pos, SEEK_SET) < 0)

    return -1;

  if (fread(buf, len, 1, data->disk->image) != 1)

    return -1;

  data->pos = ftell(data->disk->image);

  return len;

}

static int

hw_disk_instance_write(device_instance *instance,

                       const void *buf,

                       unsigned_word len)

{

  hw_disk_instance *data = device_instance_data(instance);

  DITRACE(disk, ("write - instance=%ld len=%ld\n",

                 (unsigned long)device_instance_to_external(instance),

                 (long)len));

  if ((data->pos + len) < data->pos)

    return -1; /* overflow */

  if (data->disk->read_only)

    return -1;

  if (fseek(data->disk->image, data->pos, SEEK_SET) < 0)

    return -1;

  if (fwrite(buf, len, 1, data->disk->image) != 1)

    return -1;

  data->pos = ftell(data->disk->image);

  return len;

}

static int

hw_disk_instance_seek(device_instance *instance,

                      unsigned_word pos_hi,

                      unsigned_word pos_lo)

{

  hw_disk_instance *data = device_instance_data(instance);

  if (pos_hi != 0)

    device_error(device_instance_device(instance),

                 "seek - extended addressing unimplemented");

  DITRACE(disk, ("seek - instance=%ld pos_hi=%ld pos_lo=%ld\n",

                 (unsigned long)device_instance_to_external(instance),

                 (long)pos_hi, (long)pos_lo));

  data->pos = pos_lo;

  return 0;

}

static int

hw_disk_max_transfer(device_instance *instance,

                     int n_stack_args,

                     unsigned32 stack_args[/*n_stack_args*/],

                     int n_stack_returns,

                     unsigned32 stack_returns[/*n_stack_returns*/])

{

  device *me = device_instance_device(instance);

  if ((n_stack_args != 0)

      || (n_stack_returns != 1)) {

    device_error(me, "Incorrect number of arguments for max-transfer method\n");

    return -1;

  }

  else {

    unsigned_cell max_transfer;

    if (device_find_property(me, "max-transfer"))

      max_transfer = device_find_integer_property(me, "max-transfer");

    else

      max_transfer = 512;

    DITRACE(disk, ("max-transfer - instance=%ld max-transfer=%ld\n",

                   (unsigned long)device_instance_to_external(instance),

                   (long int)max_transfer));

    stack_returns[0] = max_transfer;

    return 0;

  }

}

static int

hw_disk_block_size(device_instance *instance,

                   int n_stack_args,

                   unsigned32 stack_args[/*n_stack_args*/],

                   int n_stack_returns,

                   unsigned32 stack_returns[/*n_stack_returns*/])

{

  device *me = device_instance_device(instance);

  if ((n_stack_args != 0)

      || (n_stack_returns != 1)) {

    device_error(me, "Incorrect number of arguments for block-size method\n");

    return -1;

  }

  else {

    unsigned_cell block_size;

    if (device_find_property(me, "block-size"))

      block_size = device_find_integer_property(me, "block-size");

    else

      block_size = 512;

    DITRACE(disk, ("block-size - instance=%ld block-size=%ld\n",

                   (unsigned long)device_instance_to_external(instance),

                   (long int)block_size));

    stack_returns[0] = block_size;

    return 0;

  }

}

static int

hw_disk_nr_blocks(device_instance *instance,

                  int n_stack_args,

                  unsigned32 stack_args[/*n_stack_args*/],

                  int n_stack_returns,

                  unsigned32 stack_returns[/*n_stack_returns*/])

{

  device *me = device_instance_device(instance);

  if ((n_stack_args != 0)

      || (n_stack_returns != 1)) {

    device_error(me, "Incorrect number of arguments for block-size method\n");

    return -1;

  }

  else {

    unsigned_word nr_blocks;

    if (device_find_property(me, "#blocks"))

      nr_blocks = device_find_integer_property(me, "#blocks");

    else

      nr_blocks = -1;

    DITRACE(disk, ("#blocks - instance=%ld #blocks=%ld\n",

                   (unsigned long)device_instance_to_external(instance),

                   (long int)nr_blocks));

    stack_returns[0] = nr_blocks;

    return 0;

  }

}

static device_instance_methods hw_disk_instance_methods[] = {

  { "max-transfer", hw_disk_max_transfer },

  { "block-size", hw_disk_block_size },

  { "#blocks", hw_disk_nr_blocks },

  { NULL, },

};

static const device_instance_callbacks hw_disk_instance_callbacks = {

  hw_disk_instance_delete,

  hw_disk_instance_read,

  hw_disk_instance_write,

  hw_disk_instance_seek,

  hw_disk_instance_methods,

};

static device_instance *

hw_disk_create_instance(device *me,

                        const char *path,

                        const char *args)

{

  device_instance *instance;

  hw_disk_device *disk = device_data(me);

  hw_disk_instance *data = ZALLOC(hw_disk_instance);

  data->disk = disk;

  data->pos = 0;

  instance = device_create_instance_from(me, NULL,

                                         data,

                                         path, args,

                                         &hw_disk_instance_callbacks);

  DITRACE(disk, ("create - path=%s(%s) instance=%ld\n",

                 path, args,

                 (unsigned long)device_instance_to_external(instance)));

  return pk_disklabel_create_instance(instance, args);

}

static device_callbacks const hw_disk_callbacks = {

  { hw_disk_init_address, NULL },

  { NULL, }, /* address */

  { hw_disk_io_read_buffer,

      hw_disk_io_write_buffer, },

  { NULL, }, /* DMA */

  { NULL, }, /* interrupt */

  { NULL, }, /* unit */

  hw_disk_create_instance,

  hw_disk_ioctl,

};

static void *

hw_disk_create(const char *name,

               const device_unit *unit_address,

               const char *args)

{

  /* create the descriptor */

  hw_disk_device *hw_disk = ZALLOC(hw_disk_device);

  return hw_disk;

}

const device_descriptor hw_disk_device_descriptor[] = {

  { "disk", hw_disk_create, &hw_disk_callbacks },

  { "cdrom", hw_disk_create, &hw_disk_callbacks },

  { "floppy", hw_disk_create, &hw_disk_callbacks },

  { NULL },

};

#endif /* _HW_DISK_C_ */