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+/*****************************************************************************\
+ * layout.c
+ * $Id: layout.c,v 1.2 2006/01/24 00:25:40 dsp_llnl Exp $
+ *****************************************************************************
+ * Copyright (C) 2002-2005 The Regents of the University of California.
+ * Produced at the Lawrence Livermore National Laboratory.
+ * Written by Dave Peterson <dsp@llnl.gov> <dave_peterson@pobox.com>.
+ * UCRL-CODE-2003-012
+ * All rights reserved.
+ *
+ * This file is part of lxbios, a utility for reading/writing LinuxBIOS
+ * parameters and displaying information from the LinuxBIOS table.
+ * For details, see <http://www.llnl.gov/linux/lxbios/>.
+ *
+ * Please also read the file DISCLAIMER which is included in this software
+ * distribution.
+ *
+ * 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) version 2, dated June 1991.
+ *
+ * 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 terms and
+ * conditions of 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 "common.h"
+#include "layout.h"
+#include "cmos_lowlevel.h"
+
+typedef struct cmos_entry_item_t cmos_entry_item_t;
+
+struct cmos_entry_item_t
+ { cmos_entry_t item;
+ cmos_entry_item_t *next;
+ };
+
+typedef struct cmos_enum_item_t cmos_enum_item_t;
+
+struct cmos_enum_item_t
+ { cmos_enum_t item;
+ cmos_enum_item_t *next;
+ };
+
+static void default_cmos_layout_get_fn (void);
+static int areas_overlap (unsigned area_0_start, unsigned area_0_length,
+ unsigned area_1_start, unsigned area_1_length);
+static int entries_overlap (const cmos_entry_t *p, const cmos_entry_t *q);
+static const cmos_enum_item_t * find_first_cmos_enum_id (unsigned config_id);
+
+const char checksum_param_name[] = "check_sum";
+
+/* Newer versions of LinuxBIOS store the 3 pieces of information below in the
+ * LinuxBIOS table so we don't have to rely on hardcoded values.
+ */
+
+/* This is the offset from the start of CMOS of the first byte that the
+ * checksum is calculated over.
+ */
+#define CMOS_CHECKSUM_START 49
+
+/* This is the offset from the start of CMOS of the last byte that the
+ * checksum is calculated over.
+ */
+#define CMOS_CHECKSUM_END 125
+
+/* This is the offset from the start of CMOS where the LinuxBIOS checksum is
+ * stored.
+ */
+#define CMOS_CHECKSUM_INDEX 126
+
+/* index of first byte of checksummed area */
+unsigned cmos_checksum_start = CMOS_CHECKSUM_START;
+
+/* index of last byte of checksummed area */
+unsigned cmos_checksum_end = CMOS_CHECKSUM_END;
+
+/* index of first byte of CMOS checksum (a big-endian 16-bit value) */
+unsigned cmos_checksum_index = CMOS_CHECKSUM_INDEX;
+
+/* List is sorted in ascending order according to 'bit' field in
+ * cmos_entry_t.
+ */
+static cmos_entry_item_t *cmos_entry_list = NULL;
+
+/* List is sorted in ascending order: first by 'config_id' and then by
+ * 'value'.
+ */
+static cmos_enum_item_t *cmos_enum_list = NULL;
+
+static cmos_layout_get_fn_t cmos_layout_get_fn = default_cmos_layout_get_fn;
+
+/****************************************************************************
+ * entries_overlap
+ *
+ * Return 1 if cmos entries 'p' and 'q' overlap. Else return 0.
+ ****************************************************************************/
+static inline int entries_overlap (const cmos_entry_t *p,
+ const cmos_entry_t *q)
+ { return areas_overlap(p->bit, p->length, q->bit, q->length); }
+
+/****************************************************************************
+ * cmos_entry_to_const_item
+ *
+ * Return a pointer to the cmos_entry_item_t that 'p' is embedded within.
+ ****************************************************************************/
+static inline const cmos_entry_item_t * cmos_entry_to_const_item
+ (const cmos_entry_t *p)
+ { static const cmos_entry_t *pos = &((cmos_entry_item_t *) 0)->item;
+ unsigned long offset, address;
+
+ offset = (unsigned long) pos;
+ address = ((unsigned long) p) - offset;
+ return (const cmos_entry_item_t *) address;
+ }
+
+/****************************************************************************
+ * cmos_enum_to_const_item
+ *
+ * Return a pointer to the cmos_enum_item_t that 'p' is embedded within.
+ ****************************************************************************/
+static inline const cmos_enum_item_t * cmos_enum_to_const_item
+ (const cmos_enum_t *p)
+ { static const cmos_enum_t *pos = &((cmos_enum_item_t *) 0)->item;
+ unsigned long offset, address;
+
+ offset = (unsigned long) pos;
+ address = ((unsigned long) p) - offset;
+ return (const cmos_enum_item_t *) address;
+ }
+
+/****************************************************************************
+ * register_cmos_layout_get_fn
+ *
+ * Set 'fn' as the function that will be called to retrieve CMOS layout
+ * information.
+ ****************************************************************************/
+void register_cmos_layout_get_fn (cmos_layout_get_fn_t fn)
+ { cmos_layout_get_fn = fn; }
+
+/****************************************************************************
+ * get_cmos_layout
+ *
+ * Retrieve CMOS layout information and store it in our internal repository.
+ ****************************************************************************/
+void get_cmos_layout (void)
+ { cmos_layout_get_fn(); }
+
+/****************************************************************************
+ * add_cmos_entry
+ *
+ * Attempt to add CMOS entry 'e' to our internal repository of layout
+ * information. Return OK on success or an error code on failure. If
+ * operation fails because 'e' overlaps an existing CMOS entry, '*conflict'
+ * will be set to point to the overlapping entry.
+ ****************************************************************************/
+int add_cmos_entry (const cmos_entry_t *e, const cmos_entry_t **conflict)
+ { cmos_entry_item_t *item, *prev, *new_entry;
+
+ *conflict = NULL;
+
+ if (e->length < 1)
+ return LAYOUT_ENTRY_BAD_LENGTH;
+
+ if ((new_entry = (cmos_entry_item_t *) malloc(sizeof(*new_entry))) == NULL)
+ out_of_memory();
+
+ new_entry->item = *e;
+
+ if (cmos_entry_list == NULL)
+ { new_entry->next = NULL;
+ cmos_entry_list = new_entry;
+ return OK;
+ }
+
+ /* Find place in list to insert new entry. List is sorted in ascending
+ * order.
+ */
+ for (item = cmos_entry_list, prev = NULL;
+ (item != NULL) && (item->item.bit < e->bit);
+ prev = item, item = item->next);
+
+ if (prev == NULL)
+ { if (entries_overlap(e, &cmos_entry_list->item))
+ { *conflict = &cmos_entry_list->item;
+ goto fail;
+ }
+
+ new_entry->next = cmos_entry_list;
+ cmos_entry_list = new_entry;
+ return OK;
+ }
+
+ if (entries_overlap(&prev->item, e))
+ { *conflict = &prev->item;
+ goto fail;
+ }
+
+ if ((item != NULL) && entries_overlap(e, &item->item))
+ { *conflict = &item->item;
+ goto fail;
+ }
+
+ new_entry->next = item;
+ prev->next = new_entry;
+ return OK;
+
+fail:
+ free(new_entry);
+ return LAYOUT_ENTRY_OVERLAP;
+ }
+
+/****************************************************************************
+ * find_cmos_entry
+ *
+ * Search for a CMOS entry whose name is 'name'. Return pointer to matching
+ * entry or NULL if entry not found.
+ ****************************************************************************/
+const cmos_entry_t * find_cmos_entry (const char name[])
+ { cmos_entry_item_t *item;
+
+ for (item = cmos_entry_list; item != NULL; item = item->next)
+ { if (!strcmp(item->item.name, name))
+ return &item->item;
+ }
+
+ return NULL;
+ }
+
+/****************************************************************************
+ * first_cmos_entry
+ *
+ * Return a pointer to the first CMOS entry in our list or NULL if list is
+ * empty.
+ ****************************************************************************/
+const cmos_entry_t * first_cmos_entry (void)
+ { return (cmos_entry_list == NULL) ? NULL : &cmos_entry_list->item; }
+
+/****************************************************************************
+ * next_cmos_entry
+ *
+ * Return a pointer to next entry in list after 'last' or NULL if no more
+ * entries.
+ ****************************************************************************/
+const cmos_entry_t * next_cmos_entry (const cmos_entry_t *last)
+ { const cmos_entry_item_t *last_item, *next_item;
+
+ last_item = cmos_entry_to_const_item(last);
+ next_item = last_item->next;
+ return (next_item == NULL) ? NULL : &next_item->item;
+ }
+
+/****************************************************************************
+ * add_cmos_enum
+ *
+ * Attempt to add CMOS enum 'e' to our internal repository of layout
+ * information. Return OK on success or an error code on failure.
+ ****************************************************************************/
+int add_cmos_enum (const cmos_enum_t *e)
+ { cmos_enum_item_t *item, *prev, *new_enum;
+
+ if ((new_enum = (cmos_enum_item_t *) malloc(sizeof(*new_enum))) == NULL)
+ out_of_memory();
+
+ new_enum->item = *e;
+
+ if (cmos_enum_list == NULL)
+ { new_enum->next = NULL;
+ cmos_enum_list = new_enum;
+ return OK;
+ }
+
+ /* The list of enums is sorted in ascending order, first by 'config_id' and
+ * then by 'value'. Look for the first enum whose 'config_id' field
+ * matches 'e'.
+ */
+ for (item = cmos_enum_list, prev = NULL;
+ (item != NULL) && (item->item.config_id < e->config_id);
+ prev = item, item = item->next);
+
+ if (item == NULL)
+ { new_enum->next = NULL;
+ prev->next = new_enum;
+ return OK;
+ }
+
+ if (item->item.config_id > e->config_id)
+ { new_enum->next = item;
+
+ if (prev == NULL)
+ cmos_enum_list = new_enum;
+ else
+ prev->next = new_enum;
+
+ return OK;
+ }
+
+ /* List already contains at least one enum whose 'config_id' matches 'e'.
+ * Now find proper place to insert 'e' based on 'value'.
+ */
+ while (item->item.value < e->value)
+ { prev = item;
+ item = item->next;
+
+ if ((item == NULL) || (item->item.config_id != e->config_id))
+ { new_enum->next = item;
+ prev->next = new_enum;
+ return OK;
+ }
+ }
+
+ if (item->item.value == e->value)
+ { free(new_enum);
+ return LAYOUT_DUPLICATE_ENUM;
+ }
+
+ new_enum->next = item;
+
+ if (prev == NULL)
+ cmos_enum_list = new_enum;
+ else
+ prev->next = new_enum;
+
+ return OK;
+ }
+
+/****************************************************************************
+ * find_cmos_enum
+ *
+ * Search for an enum that matches 'config_id' and 'value'. If found, return
+ * a pointer to the mathcing enum. Else return NULL.
+ ****************************************************************************/
+const cmos_enum_t * find_cmos_enum (unsigned config_id,
+ unsigned long long value)
+ { const cmos_enum_item_t *item;
+
+ if ((item = find_first_cmos_enum_id(config_id)) == NULL)
+ return NULL;
+
+ while (item->item.value < value)
+ { item = item->next;
+
+ if ((item == NULL) || (item->item.config_id != config_id))
+ return NULL;
+ }
+
+ return (item->item.value == value) ? &item->item : NULL;
+ }
+
+/****************************************************************************
+ * first_cmos_enum
+ *
+ * Return a pointer to the first CMOS enum in our list or NULL if list is
+ * empty.
+ ****************************************************************************/
+const cmos_enum_t * first_cmos_enum (void)
+ { return (cmos_enum_list == NULL) ? NULL : &cmos_enum_list->item; }
+
+/****************************************************************************
+ * next_cmos_enum
+ *
+ * Return a pointer to next enum in list after 'last' or NULL if no more
+ * enums.
+ ****************************************************************************/
+const cmos_enum_t * next_cmos_enum (const cmos_enum_t *last)
+ { const cmos_enum_item_t *last_item, *next_item;
+
+ last_item = cmos_enum_to_const_item(last);
+ next_item = last_item->next;
+ return (next_item == NULL) ? NULL : &next_item->item;
+ }
+
+/****************************************************************************
+ * first_cmos_enum_id
+ *
+ * Return a pointer to the first CMOS enum in our list that matches
+ * 'config_id' or NULL if there are no matching enums.
+ ****************************************************************************/
+const cmos_enum_t * first_cmos_enum_id (unsigned config_id)
+ { const cmos_enum_item_t *item;
+
+ item = find_first_cmos_enum_id(config_id);
+ return (item == NULL) ? NULL : &item->item;
+ }
+
+/****************************************************************************
+ * next_cmos_enum_id
+ *
+ * Return a pointer to next enum in list after 'last' that matches the
+ * 'config_id' field of 'last' or NULL if there are no more matching enums.
+ ****************************************************************************/
+const cmos_enum_t * next_cmos_enum_id (const cmos_enum_t *last)
+ { const cmos_enum_item_t *item;
+
+ item = cmos_enum_to_const_item(last)->next;
+ return ((item == NULL) || (item->item.config_id != last->config_id)) ?
+ NULL : &item->item;
+ }
+
+/****************************************************************************
+ * is_checksum_name
+ *
+ * Return 1 if 'name' matches the name of the parameter representing the CMOS
+ * checksum. Else return 0.
+ ****************************************************************************/
+int is_checksum_name (const char name[])
+ { return !strcmp(name, checksum_param_name); }
+
+/****************************************************************************
+ * checksum_layout_to_bytes
+ *
+ * On entry, '*layout' contains checksum-related layout information expressed
+ * in bits. Perform sanity checking on the information and convert it from
+ * bit positions to byte positions. Return OK on success or an error code if
+ * a sanity check fails.
+ ****************************************************************************/
+int checksum_layout_to_bytes (cmos_checksum_layout_t *layout)
+ { unsigned start, end, index;
+
+ start = layout->summed_area_start;
+ end = layout->summed_area_end;
+ index = layout->checksum_at;
+
+ if (start % 8)
+ return LAYOUT_SUMMED_AREA_START_NOT_ALIGNED;
+
+ if ((end % 8) != 7)
+ return LAYOUT_SUMMED_AREA_END_NOT_ALIGNED;
+
+ if (index % 8)
+ return LAYOUT_CHECKSUM_LOCATION_NOT_ALIGNED;
+
+ if (end <= start)
+ return LAYOUT_INVALID_SUMMED_AREA;
+
+ /* Convert bit positions to byte positions. */
+ start /= 8;
+ end /= 8; /* equivalent to "end = ((end - 7) / 8)" */
+ index /= 8;
+
+ if (verify_cmos_byte_index(start) || verify_cmos_byte_index(end))
+ return LAYOUT_SUMMED_AREA_OUT_OF_RANGE;
+
+ if (verify_cmos_byte_index(index))
+ return LAYOUT_CHECKSUM_LOCATION_OUT_OF_RANGE;
+
+ /* checksum occupies 16 bits */
+ if (areas_overlap(start, end - start + 1, index, index + 1))
+ return LAYOUT_CHECKSUM_OVERLAPS_SUMMED_AREA;
+
+ layout->summed_area_start = start;
+ layout->summed_area_end = end;
+ layout->checksum_at = index;
+ return OK;
+ }
+
+/****************************************************************************
+ * checksum_layout_to_bits
+ *
+ * On entry, '*layout' contains checksum-related layout information expressed
+ * in bytes. Convert this information to bit positions.
+ ****************************************************************************/
+void checksum_layout_to_bits (cmos_checksum_layout_t *layout)
+ { layout->summed_area_start *= 8;
+ layout->summed_area_end = (layout->summed_area_end * 8) + 7;
+ layout->checksum_at *= 8;
+ }
+
+/****************************************************************************
+ * default_cmos_layout_get_fn
+ *
+ * If this function is ever called, it means that an appropriate callback for
+ * obtaining CMOS layout information was not set before attempting to
+ * retrieve layout information.
+ ****************************************************************************/
+static void default_cmos_layout_get_fn (void)
+ { BUG(); }
+
+/****************************************************************************
+ * areas_overlap
+ *
+ * Return 1 if the two given areas overlap. Else return 0.
+ ****************************************************************************/
+static int areas_overlap (unsigned area_0_start, unsigned area_0_length,
+ unsigned area_1_start, unsigned area_1_length)
+ { unsigned area_0_end, area_1_end;
+
+ area_0_end = area_0_start + area_0_length - 1;
+ area_1_end = area_1_start + area_1_length - 1;
+ return ((area_1_start <= area_0_end) && (area_0_start <= area_1_end));
+ }
+
+/****************************************************************************
+ * find_first_cmos_enum_id
+ *
+ * Return a pointer to the first item in our list of enums that matches
+ * 'config_id'. Return NULL if there is no matching enum.
+ ****************************************************************************/
+static const cmos_enum_item_t * find_first_cmos_enum_id (unsigned config_id)
+ { cmos_enum_item_t *item;
+
+ for (item = cmos_enum_list;
+ (item != NULL) && (item->item.config_id < config_id);
+ item = item->next);
+
+ return ((item == NULL) || (item->item.config_id > config_id)) ?
+ NULL : item;
+ }