diff options
Diffstat (limited to 'arch/powerpc')
| -rw-r--r-- | arch/powerpc/mm/ppc_mmu_32.c | 18 |
1 files changed, 14 insertions, 4 deletions
diff --git a/arch/powerpc/mm/ppc_mmu_32.c b/arch/powerpc/mm/ppc_mmu_32.c index f29d2f118b44..5d9c3ff728c9 100644 --- a/arch/powerpc/mm/ppc_mmu_32.c +++ b/arch/powerpc/mm/ppc_mmu_32.c @@ -98,10 +98,20 @@ static int find_free_bat(void) return -1; } +/* + * This function calculates the size of the larger block usable to map the + * beginning of an area based on the start address and size of that area: + * - max block size is 8M on 601 and 256 on other 6xx. + * - base address must be aligned to the block size. So the maximum block size + * is identified by the lowest bit set to 1 in the base address (for instance + * if base is 0x16000000, max size is 0x02000000). + * - block size has to be a power of two. This is calculated by finding the + * highest bit set to 1. + */ static unsigned int block_size(unsigned long base, unsigned long top) { unsigned int max_size = (cpu_has_feature(CPU_FTR_601) ? 8 : 256) << 20; - unsigned int base_shift = (fls(base) - 1) & 31; + unsigned int base_shift = (ffs(base) - 1) & 31; unsigned int block_shift = (fls(top - base) - 1) & 31; return min3(max_size, 1U << base_shift, 1U << block_shift); @@ -157,7 +167,7 @@ static unsigned long __init __mmu_mapin_ram(unsigned long base, unsigned long to unsigned long __init mmu_mapin_ram(unsigned long base, unsigned long top) { - int done; + unsigned long done; unsigned long border = (unsigned long)__init_begin - PAGE_OFFSET; if (__map_without_bats) { @@ -169,10 +179,10 @@ unsigned long __init mmu_mapin_ram(unsigned long base, unsigned long top) return __mmu_mapin_ram(base, top); done = __mmu_mapin_ram(base, border); - if (done != border - base) + if (done != border) return done; - return done + __mmu_mapin_ram(border, top); + return __mmu_mapin_ram(border, top); } void mmu_mark_initmem_nx(void) |