350 lines
9.5 KiB
C
350 lines
9.5 KiB
C
/* dv-nvram.c -- Generic driver for a non volatile ram (battery saved)
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Copyright (C) 1999-2015 Free Software Foundation, Inc.
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Written by Stephane Carrez (stcarrez@worldnet.fr)
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(From a driver model Contributed by Cygnus Solutions.)
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include "sim-main.h"
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#include "hw-main.h"
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#include "sim-assert.h"
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#include <unistd.h>
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#include <fcntl.h>
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#include <errno.h>
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/* DEVICE
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nvram - Non Volatile Ram
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DESCRIPTION
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Implements a generic battery saved CMOS ram. This ram device does
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not contain any realtime clock and does not generate any interrupt.
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The ram content is loaded from a file and saved when it is changed.
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It is intended to be generic.
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PROPERTIES
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reg <base> <length>
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Base and size of the non-volatile ram bank.
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file <path>
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Path where the memory must be saved or loaded when we start.
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mode {map | save-modified | save-all}
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Controls how to load and save the memory content.
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map The file is mapped in memory
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save-modified The simulator keeps an open file descriptor to
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the file and saves portion of memory which are
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modified.
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save-all The simulator saves the complete memory each time
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it's modified (it does not keep an open file
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descriptor).
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PORTS
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None.
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NOTES
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This device is independent of the Motorola 68hc11.
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*/
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/* static functions */
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/* Control of how to access the ram and save its content. */
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enum nvram_mode
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{
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/* Save the complete ram block each time it's changed.
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We don't keep an open file descriptor. This should be
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ok for small memory banks. */
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NVRAM_SAVE_ALL,
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/* Save only the memory bytes which are modified.
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This mode means that we have to keep an open file
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descriptor (O_RDWR). It's good for middle sized memory banks. */
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NVRAM_SAVE_MODIFIED,
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/* Map file in memory (not yet implemented).
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This mode is suitable for large memory banks. We don't allocate
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a buffer to represent the ram, instead it's mapped in memory
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with mmap. */
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NVRAM_MAP_FILE
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};
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struct nvram
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{
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address_word base_address; /* Base address of ram. */
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unsigned size; /* Size of ram. */
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unsigned8 *data; /* Pointer to ram memory. */
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const char *file_name; /* Path of ram file. */
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int fd; /* File description of opened ram file. */
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enum nvram_mode mode; /* How load/save ram file. */
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};
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/* Finish off the partially created hw device. Attach our local
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callbacks. Wire up our port names etc. */
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static hw_io_read_buffer_method nvram_io_read_buffer;
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static hw_io_write_buffer_method nvram_io_write_buffer;
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static void
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attach_nvram_regs (struct hw *me, struct nvram *controller)
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{
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unsigned_word attach_address;
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int attach_space;
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unsigned attach_size;
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reg_property_spec reg;
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int result, oerrno;
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/* Get ram bank description (base and size). */
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if (hw_find_property (me, "reg") == NULL)
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hw_abort (me, "Missing \"reg\" property");
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if (!hw_find_reg_array_property (me, "reg", 0, ®))
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hw_abort (me, "\"reg\" property must contain one addr/size entry");
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hw_unit_address_to_attach_address (hw_parent (me),
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®.address,
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&attach_space,
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&attach_address,
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me);
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hw_unit_size_to_attach_size (hw_parent (me),
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®.size,
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&attach_size, me);
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hw_attach_address (hw_parent (me), 0,
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attach_space, attach_address, attach_size,
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me);
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controller->mode = NVRAM_SAVE_ALL;
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controller->base_address = attach_address;
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controller->size = attach_size;
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controller->fd = -1;
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/* Get the file where the ram content must be loaded/saved. */
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if(hw_find_property (me, "file") == NULL)
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hw_abort (me, "Missing \"file\" property");
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controller->file_name = hw_find_string_property (me, "file");
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/* Get the mode which defines how to save the memory. */
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if(hw_find_property (me, "mode") != NULL)
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{
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const char *value = hw_find_string_property (me, "mode");
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if (strcmp (value, "map") == 0)
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controller->mode = NVRAM_MAP_FILE;
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else if (strcmp (value, "save-modified") == 0)
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controller->mode = NVRAM_SAVE_MODIFIED;
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else if (strcmp (value, "save-all") == 0)
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controller->mode = NVRAM_SAVE_ALL;
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else
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hw_abort (me, "illegal value for mode parameter `%s': "
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"use map, save-modified or save-all", value);
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}
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/* Initialize the ram by loading/mapping the file in memory.
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If the file does not exist, create and give it some content. */
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switch (controller->mode)
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{
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case NVRAM_MAP_FILE:
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hw_abort (me, "'map' mode is not yet implemented, use 'save-modified'");
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break;
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case NVRAM_SAVE_MODIFIED:
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case NVRAM_SAVE_ALL:
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controller->data = (char*) hw_malloc (me, attach_size);
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if (controller->data == 0)
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hw_abort (me, "Not enough memory, try to use the mode 'map'");
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memset (controller->data, 0, attach_size);
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controller->fd = open (controller->file_name, O_RDWR);
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if (controller->fd < 0)
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{
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controller->fd = open (controller->file_name,
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O_RDWR | O_CREAT, 0644);
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if (controller->fd < 0)
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hw_abort (me, "Cannot open or create file '%s'",
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controller->file_name);
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result = write (controller->fd, controller->data, attach_size);
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if (result != attach_size)
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{
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oerrno = errno;
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hw_free (me, controller->data);
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close (controller->fd);
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errno = oerrno;
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hw_abort (me, "Failed to save the ram content");
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}
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}
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else
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{
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result = read (controller->fd, controller->data, attach_size);
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if (result != attach_size)
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{
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oerrno = errno;
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hw_free (me, controller->data);
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close (controller->fd);
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errno = oerrno;
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hw_abort (me, "Failed to load the ram content");
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}
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}
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if (controller->mode == NVRAM_SAVE_ALL)
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{
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close (controller->fd);
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controller->fd = -1;
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}
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break;
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default:
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break;
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}
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}
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static void
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nvram_finish (struct hw *me)
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{
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struct nvram *controller;
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controller = HW_ZALLOC (me, struct nvram);
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set_hw_data (me, controller);
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set_hw_io_read_buffer (me, nvram_io_read_buffer);
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set_hw_io_write_buffer (me, nvram_io_write_buffer);
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/* Attach ourself to our parent bus. */
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attach_nvram_regs (me, controller);
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}
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/* generic read/write */
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static unsigned
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nvram_io_read_buffer (struct hw *me,
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void *dest,
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int space,
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unsigned_word base,
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unsigned nr_bytes)
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{
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struct nvram *controller = hw_data (me);
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HW_TRACE ((me, "read 0x%08lx %d [%ld]",
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(long) base, (int) nr_bytes,
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(long) (base - controller->base_address)));
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base -= controller->base_address;
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if (base + nr_bytes > controller->size)
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nr_bytes = controller->size - base;
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memcpy (dest, &controller->data[base], nr_bytes);
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return nr_bytes;
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}
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static unsigned
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nvram_io_write_buffer (struct hw *me,
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const void *source,
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int space,
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unsigned_word base,
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unsigned nr_bytes)
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{
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struct nvram *controller = hw_data (me);
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HW_TRACE ((me, "write 0x%08lx %d [%ld]",
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(long) base, (int) nr_bytes,
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(long) (base - controller->base_address)));
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base -= controller->base_address;
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if (base + nr_bytes > controller->size)
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nr_bytes = controller->size - base;
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switch (controller->mode)
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{
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case NVRAM_SAVE_ALL:
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{
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int fd, result, oerrno;
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fd = open (controller->file_name, O_WRONLY, 0644);
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if (fd < 0)
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{
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return 0;
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}
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memcpy (&controller->data[base], source, nr_bytes);
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result = write (fd, controller->data, controller->size);
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oerrno = errno;
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close (fd);
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errno = oerrno;
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if (result != controller->size)
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{
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return 0;
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}
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return nr_bytes;
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}
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case NVRAM_SAVE_MODIFIED:
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{
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off_t pos;
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int result;
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pos = lseek (controller->fd, (off_t) base, SEEK_SET);
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if (pos != (off_t) base)
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return 0;
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result = write (controller->fd, source, nr_bytes);
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if (result < 0)
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return 0;
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nr_bytes = result;
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break;
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}
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default:
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break;
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}
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memcpy (&controller->data[base], source, nr_bytes);
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return nr_bytes;
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}
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const struct hw_descriptor dv_nvram_descriptor[] = {
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{ "nvram", nvram_finish, },
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{ NULL },
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};
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