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// Support for building memory maps suitable for int 15 e820 calls.
//
// Copyright (C) 2008,2009 Kevin O'Connor <kevin@koconnor.net>
//
// This file may be distributed under the terms of the GNU LGPLv3 license.
#include "memmap.h" // struct e820entry
#include "util.h" // dprintf.h
#include "biosvar.h" // SET_EBDA
/****************************************************************
* e820 memory map
****************************************************************/
// Remove an entry from the e820_list.
static void
remove_e820(int i)
{
e820_count--;
memmove(&e820_list[i], &e820_list[i+1]
, sizeof(e820_list[0]) * (e820_count - i));
}
// Insert an entry in the e820_list at the given position.
static void
insert_e820(int i, u64 start, u64 size, u32 type)
{
if (e820_count >= CONFIG_MAX_E820) {
dprintf(1, "Overflowed e820 list!\n");
return;
}
memmove(&e820_list[i+1], &e820_list[i]
, sizeof(e820_list[0]) * (e820_count - i));
e820_count++;
struct e820entry *e = &e820_list[i];
e->start = start;
e->size = size;
e->type = type;
}
// Show the current e820_list.
static void
dump_map()
{
dprintf(1, "e820 map has %d items:\n", e820_count);
int i;
for (i=0; i<e820_count; i++) {
struct e820entry *e = &e820_list[i];
u64 e_end = e->start + e->size;
dprintf(1, " %d: %08x%08x - %08x%08x = %d\n", i
, (u32)(e->start >> 32), (u32)e->start
, (u32)(e_end >> 32), (u32)e_end
, e->type);
}
}
// Add a new entry to the list. This scans for overlaps and keeps the
// list sorted.
void
add_e820(u64 start, u64 size, u32 type)
{
dprintf(8, "Add to e820 map: %08x %08x %d\n", (u32)start, (u32)size, type);
if (! size)
// Huh? Nothing to do.
return;
// Find position of new item (splitting existing item if needed).
u64 end = start + size;
int i;
for (i=0; i<e820_count; i++) {
struct e820entry *e = &e820_list[i];
u64 e_end = e->start + e->size;
if (start > e_end)
continue;
// Found position - check if an existing item needs to be split.
if (start > e->start) {
if (type == e->type) {
// Same type - merge them.
size += start - e->start;
start = e->start;
} else {
// Split existing item.
e->size = start - e->start;
i++;
if (e_end > end)
insert_e820(i, end, e_end - end, e->type);
}
}
break;
}
// Remove/adjust existing items that are overlapping.
while (i<e820_count) {
struct e820entry *e = &e820_list[i];
if (end < e->start)
// No overlap - done.
break;
u64 e_end = e->start + e->size;
if (end >= e_end) {
// Existing item completely overlapped - remove it.
remove_e820(i);
continue;
}
// Not completely overlapped - adjust its start.
e->start = end;
e->size = e_end - end;
if (type == e->type) {
// Same type - merge them.
size += e->size;
remove_e820(i);
}
break;
}
// Insert new item.
if (type != E820_HOLE)
insert_e820(i, start, size, type);
//dump_map();
}
// Find highest area of 32bit memory that can hold the given size.
struct e820entry *
find_high_area(u32 size)
{
int i;
for (i=e820_count-1; i>=0; i--) {
struct e820entry *e = &e820_list[i];
u64 end = e->start + e->size;
if (e->type != E820_RAM || end > 0xffffffff || e->size < size)
continue;
if (end < 1024*1024 + size)
break;
return e;
}
return NULL;
}
// Prep for memmap stuff - init bios table locations.
void
memmap_setup()
{
e820_count = 0;
}
// Report on final memory locations.
void
memmap_finalize()
{
dump_map();
}
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