/* $Id$ */
#include <rtems.h>
#include <libcpu/mmu.h>
#include <libcpu/page.h>
#include <rtems/bspIo.h>
#include <libcpu/pte121.h>
/* Default setup of the page tables. This is a weak
* alias, so applications may easily override this
* default setup.
*
* NOTE: while it is possible to change the individual
* mappings, the page table itself MUST be
* allocated at the top of the physical memory!
* bspstart.c RELIES on this.
* Also, the 'setup' routine must reduce
* *pmemsize by the size of the page table.
*/
/* Author: Till Straumann, <strauman@slac.stanford.edu>, 4/2002 */
Triv121PgTbl
BSP_pgtbl_setup(unsigned long) __attribute__ (( weak, alias("__BSP_default_pgtbl_setup") ));
Triv121PgTbl
__BSP_default_pgtbl_setup(unsigned int *pmemsize)
{
Triv121PgTbl pt;
unsigned ldPtSize,tmp;
/* Allocate a page table large enough to map
* the entire physical memory. We put the page
* table at the top of the physical memory.
*/
/* get minimal size (log base 2) of PT for
* this board's memory
*/
ldPtSize = triv121PgTblLdMinSize(*pmemsize);
ldPtSize++; /* double this amount -- then why? */
/* allocate the page table at the top of the physical
* memory - THIS IS NOT AN OPTION - bspstart.c RELIES
* ON THIS LAYOUT! (the size, however may be changed)
*/
if ( (pt = triv121PgTblInit(*pmemsize - (1<<ldPtSize), ldPtSize)) ) {
/* get those from the linker script.
* NOTE THAT THE CORRECTNESS OF THE LINKER SCRIPT IS CRUCIAL
*/
extern unsigned long __DATA_START__[], _etext[];
/* map text and RO data read-only */
tmp = triv121PgTblMap(
pt,
TRIV121_121_VSID,
0,
(PAGE_ALIGN((unsigned long)_etext) - 0) >> PG_SHIFT,
0, /* WIMG */
TRIV121_PP_RO_PAGE);
if (TRIV121_MAP_SUCCESS != tmp) {
printk("Unable to map page index %i; reverting to BAT0\n",
tmp);
pt = 0;
} else {
/* map the rest (without the page table itself) RW */
tmp = triv121PgTblMap(
pt,
TRIV121_121_VSID,
(unsigned long)__DATA_START__,
(*pmemsize - (1<<ldPtSize) - (unsigned long)__DATA_START__ )>> PG_SHIFT,
0, /* WIMG */
TRIV121_PP_RW_PAGE);
if (TRIV121_MAP_SUCCESS != tmp) {
printk("Unable to map page index %i; reverting to BAT0\n",
tmp);
pt = 0;
}
}
} else {
printk("WARNING: unable to allocate page table, keeping DBAT0\n");
}
if (pt) {
#ifdef SHOW_MORE_INIT_SETTINGS
printk("Setting up page table mappings; protecting text/read-only data from write access\n");
#endif
/* SUCCESS; reduce available memory by size of the page table */
*pmemsize -= (1<<ldPtSize);
}
return pt;
}
