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binutils-gdb/sim/m68hc11/dv-nvram.c

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/* dv-nvram.c -- Generic driver for a non volatile ram (battery saved)
Copyright (C) 1999, 2000 Free Software Foundation, Inc.
Written by Stephane Carrez (stcarrez@worldnet.fr)
(From a driver model Contributed by Cygnus Solutions.)
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 "sim-main.h"
#include "hw-main.h"
#include "sim-assert.h"
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
/* DEVICE
nvram - Non Volatile Ram
DESCRIPTION
Implements a generic battery saved CMOS ram. This ram device does
not contain any realtime clock and does not generate any interrupt.
The ram content is loaded from a file and saved when it is changed.
It is intended to be generic.
PROPERTIES
reg <base> <length>
Base and size of the non-volatile ram bank.
file <path>
Path where the memory must be saved or loaded when we start.
mode {map | save-modified | save-all}
Controls how to load and save the memory content.
map The file is mapped in memory
save-modified The simulator keeps an open file descriptor to
the file and saves portion of memory which are
modified.
save-all The simulator saves the complete memory each time
it's modified (it does not keep an open file
descriptor).
PORTS
None.
NOTES
This device is independent of the Motorola 68hc11.
*/
/* static functions */
/* Control of how to access the ram and save its content. */
enum nvram_mode
{
/* Save the complete ram block each time it's changed.
We don't keep an open file descriptor. This should be
ok for small memory banks. */
NVRAM_SAVE_ALL,
/* Save only the memory bytes which are modified.
This mode means that we have to keep an open file
descriptor (O_RDWR). It's good for middle sized memory banks. */
NVRAM_SAVE_MODIFIED,
/* Map file in memory (not yet implemented).
This mode is suitable for large memory banks. We don't allocate
a buffer to represent the ram, instead it's mapped in memory
with mmap. */
NVRAM_MAP_FILE
};
struct nvram
{
address_word base_address; /* Base address of ram. */
unsigned size; /* Size of ram. */
unsigned8 *data; /* Pointer to ram memory. */
const char *file_name; /* Path of ram file. */
int fd; /* File description of opened ram file. */
enum nvram_mode mode; /* How load/save ram file. */
};
/* Finish off the partially created hw device. Attach our local
callbacks. Wire up our port names etc. */
static hw_io_read_buffer_method nvram_io_read_buffer;
static hw_io_write_buffer_method nvram_io_write_buffer;
static void
attach_nvram_regs (struct hw *me, struct nvram *controller)
{
unsigned_word attach_address;
int attach_space;
unsigned attach_size;
reg_property_spec reg;
int result, oerrno;
/* Get ram bank description (base and size). */
if (hw_find_property (me, "reg") == NULL)
hw_abort (me, "Missing \"reg\" property");
if (!hw_find_reg_array_property (me, "reg", 0, &reg))
hw_abort (me, "\"reg\" property must contain one addr/size entry");
hw_unit_address_to_attach_address (hw_parent (me),
&reg.address,
&attach_space,
&attach_address,
me);
hw_unit_size_to_attach_size (hw_parent (me),
&reg.size,
&attach_size, me);
hw_attach_address (hw_parent (me), 0,
attach_space, attach_address, attach_size,
me);
controller->mode = NVRAM_SAVE_ALL;
controller->base_address = attach_address;
controller->size = attach_size;
controller->fd = -1;
/* Get the file where the ram content must be loaded/saved. */
if(hw_find_property (me, "file") == NULL)
hw_abort (me, "Missing \"file\" property");
controller->file_name = hw_find_string_property (me, "file");
/* Get the mode which defines how to save the memory. */
if(hw_find_property (me, "mode") != NULL)
{
const char *value = hw_find_string_property (me, "mode");
if (strcmp (value, "map") == 0)
controller->mode = NVRAM_MAP_FILE;
else if (strcmp (value, "save-modified") == 0)
controller->mode = NVRAM_SAVE_MODIFIED;
else if (strcmp (value, "save-all") == 0)
controller->mode = NVRAM_SAVE_ALL;
else
hw_abort (me, "illegal value for mode parameter `%s': "
"use map, save-modified or save-all", value);
}
/* Initialize the ram by loading/mapping the file in memory.
If the file does not exist, create and give it some content. */
switch (controller->mode)
{
case NVRAM_MAP_FILE:
hw_abort (me, "'map' mode is not yet implemented, use 'save-modified'");
break;
case NVRAM_SAVE_MODIFIED:
case NVRAM_SAVE_ALL:
controller->data = (char*) hw_malloc (me, attach_size);
if (controller->data == 0)
hw_abort (me, "Not enough memory, try to use the mode 'map'");
memset (controller->data, 0, attach_size);
controller->fd = open (controller->file_name, O_RDWR);
if (controller->fd < 0)
{
controller->fd = open (controller->file_name,
O_RDWR | O_CREAT, 0644);
if (controller->fd < 0)
hw_abort (me, "Cannot open or create file '%s'",
controller->file_name);
result = write (controller->fd, controller->data, attach_size);
if (result != attach_size)
{
oerrno = errno;
hw_free (me, controller->data);
close (controller->fd);
errno = oerrno;
hw_abort (me, "Failed to save the ram content");
}
}
else
{
result = read (controller->fd, controller->data, attach_size);
if (result != attach_size)
{
oerrno = errno;
hw_free (me, controller->data);
close (controller->fd);
errno = oerrno;
hw_abort (me, "Failed to load the ram content");
}
}
if (controller->mode == NVRAM_SAVE_ALL)
{
close (controller->fd);
controller->fd = -1;
}
break;
default:
break;
}
}
static void
nvram_finish (struct hw *me)
{
struct nvram *controller;
controller = HW_ZALLOC (me, struct nvram);
set_hw_data (me, controller);
set_hw_io_read_buffer (me, nvram_io_read_buffer);
set_hw_io_write_buffer (me, nvram_io_write_buffer);
/* Attach ourself to our parent bus. */
attach_nvram_regs (me, controller);
}
/* generic read/write */
static unsigned
nvram_io_read_buffer (struct hw *me,
void *dest,
int space,
unsigned_word base,
unsigned nr_bytes)
{
struct nvram *controller = hw_data (me);
HW_TRACE ((me, "read 0x%08lx %d [%ld]",
(long) base, (int) nr_bytes,
(long) (base - controller->base_address)));
base -= controller->base_address;
if (base + nr_bytes > controller->size)
nr_bytes = controller->size - base;
memcpy (dest, &controller->data[base], nr_bytes);
return nr_bytes;
}
static unsigned
nvram_io_write_buffer (struct hw *me,
const void *source,
int space,
unsigned_word base,
unsigned nr_bytes)
{
struct nvram *controller = hw_data (me);
HW_TRACE ((me, "write 0x%08lx %d [%ld]",
(long) base, (int) nr_bytes,
(long) (base - controller->base_address)));
base -= controller->base_address;
if (base + nr_bytes > controller->size)
nr_bytes = controller->size - base;
switch (controller->mode)
{
case NVRAM_SAVE_ALL:
{
int fd, result, oerrno;
fd = open (controller->file_name, O_WRONLY, 0644);
if (fd < 0)
{
return 0;
}
memcpy (&controller->data[base], source, nr_bytes);
result = write (fd, controller->data, controller->size);
oerrno = errno;
close (fd);
errno = oerrno;
if (result != controller->size)
{
return 0;
}
return nr_bytes;
}
case NVRAM_SAVE_MODIFIED:
{
off_t pos;
int result;
pos = lseek (controller->fd, (off_t) base, SEEK_SET);
if (pos != (off_t) base)
return 0;
result = write (controller->fd, source, nr_bytes);
if (result < 0)
return 0;
nr_bytes = result;
break;
}
default:
break;
}
memcpy (&controller->data[base], source, nr_bytes);
return nr_bytes;
}
const struct hw_descriptor dv_nvram_descriptor[] = {
{ "nvram", nvram_finish, },
{ NULL },
};
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