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/*
* This file contains the routines for initializing the MMU
* on the 8xx series of chips.
* -- christophe
*
* Derived from arch/powerpc/mm/40x_mmu.c:
*
* 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; either version
* 2 of the License, or (at your option) any later version.
*
*/
#include <linux/memblock.h>
#include "mmu_decl.h"
extern int __map_without_ltlbs;
/*
* MMU_init_hw does the chip-specific initialization of the MMU hardware.
*/
void __init MMU_init_hw(void)
{
/* Nothing to do for the time being but keep it similar to other PPC */
}
#define LARGE_PAGE_SIZE_4M (1<<22)
#define LARGE_PAGE_SIZE_8M (1<<23)
#define LARGE_PAGE_SIZE_64M (1<<26)
unsigned long __init mmu_mapin_ram(unsigned long top)
{
unsigned long v, s, mapped;
phys_addr_t p;
v = KERNELBASE;
p = 0;
s = top;
if (__map_without_ltlbs)
return 0;
#ifdef CONFIG_PPC_4K_PAGES
while (s >= LARGE_PAGE_SIZE_8M) {
pmd_t *pmdp;
unsigned long val = p | MD_PS8MEG;
pmdp = pmd_offset(pud_offset(pgd_offset_k(v), v), v);
*pmdp++ = __pmd(val);
*pmdp++ = __pmd(val + LARGE_PAGE_SIZE_4M);
v += LARGE_PAGE_SIZE_8M;
p += LARGE_PAGE_SIZE_8M;
s -= LARGE_PAGE_SIZE_8M;
}
#else /* CONFIG_PPC_16K_PAGES */
while (s >= LARGE_PAGE_SIZE_64M) {
pmd_t *pmdp;
unsigned long val = p | MD_PS8MEG;
pmdp = pmd_offset(pud_offset(pgd_offset_k(v), v), v);
*pmdp++ = __pmd(val);
v += LARGE_PAGE_SIZE_64M;
p += LARGE_PAGE_SIZE_64M;
s -= LARGE_PAGE_SIZE_64M;
}
#endif
mapped = top - s;
/* If the size of RAM is not an exact power of two, we may not
* have covered RAM in its entirety with 8 MiB
* pages. Consequently, restrict the top end of RAM currently
* allocable so that calls to the MEMBLOCK to allocate PTEs for "tail"
* coverage with normal-sized pages (or other reasons) do not
* attempt to allocate outside the allowed range.
*/
memblock_set_current_limit(mapped);
return mapped;
}
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