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/*
* Open Hack'Ware BIOS memory management.
*
* Copyright (c) 2004-2005 Jocelyn Mayer
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License V2
* as published by the Free Software Foundation
*
* 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 <stdlib.h>
#include "bios.h"
#if 0
static uint8_t *page_bitmap;
static uint32_t memory_size;
static void mark_page_in_use (uint32_t page_nb)
{
uint32_t offset, bit;
offset = page_nb >> 3;
bit = page_nb & 7;
page_bitmap[offset] |= 1 << bit;
}
static void mark_page_free (uint32_t page_nb)
{
uint32_t offset, bit;
offset = page_nb >> 3;
bit = page_nb & 7;
page_bitmap[offset] &= ~(1 << bit);
}
static int is_page_in_use (uint32_t page_nb)
{
uint32_t offset, bit;
offset = page_nb >> 3;
bit = page_nb & 7;
return (page_bitmap[offset] & (~(1 << bit))) != 0;
}
void mm_init (uint32_t memsize)
{
uint32_t page_start, page_ram_start, page, ram_start;
uint32_t nb_pages, bitmap_size;
/* Init bitmap */
ram_start = (uint32_t)(&_ram_start);
ram_start = (ram_start + (1 << 12) - 1) & ~((1 << 12) - 1);
page_bitmap = (void *)ram_start;
nb_pages = (memsize + (1 << 12) - 1) >> 12;
bitmap_size = (nb_pages + 7) >> 3;
/* First mark all pages as free */
memset(page_bitmap, 0, bitmap_size);
/* Mark all pages used by the BIOS as used (code + data + bitmap) */
page_start = (uint32_t)(0x05800000) >> 12; /* TO FIX */
ram_start += bitmap_size;
ram_start = (ram_start + (1 << 12) - 1) & ~((1 << 12) - 1);
page_ram_start = ram_start >> 12;
for (page = page_start; page < page_ram_start; page++)
mark_page_in_use(page);
memory_size = memsize;
}
void *page_get (int nb_pages)
{
uint32_t page_start, page_end, page;
int nb;
page_start = (uint32_t)(0x05800000) >> 12; /* TO FIX */
page_end = memory_size >> 12;
for (page = page_start; page < page_end; ) {
/* Skip all full "blocs" */
for (; page < page_end; page += 8) {
if (page_bitmap[page >> 3] != 0xFF)
break;
}
for (nb = 0; page < page_end; page++) {
if (!is_page_in_use(page)) {
nb++;
if (nb == nb_pages) {
/* Found ! */
for (; nb >= 0; nb--, page--)
mark_page_in_use(page);
return (void *)(page << 12);
}
}
}
}
return NULL;
}
void page_put (void *addr, int nb_pages)
{
uint32_t page_start, page_end, page;
page_start = (uint32_t)addr >> 12;
page_end = page_start + nb_pages;
for (page = page_start; page < page_end; page++) {
if (!is_page_in_use(page))
printf("ERROR: page %u has already been freed !\n", page);
mark_page_free(page);
}
}
#else
static uint8_t *page_alloc;
void mm_init (unused uint32_t memsize)
{
uint32_t ram_start;
ram_start = (uint32_t)(&_ram_start);
ram_start = (ram_start + (1 << 12) - 1) & ~((1 << 12) - 1);
page_alloc = (void *)ram_start;
}
void *page_get (unused int nb_pages)
{
void *ret;
ret = page_alloc;
page_alloc += nb_pages << 12;
memset(ret, 0, nb_pages << 12);
return ret;
}
void page_put (unused void *addr, unused int nb_pages)
{
}
#endif
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