mirror of https://gitee.com/openkylin/linux.git
84 lines
2.0 KiB
C
84 lines
2.0 KiB
C
/*
|
|
* 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;
|
|
}
|