diff options
Diffstat (limited to 'arch/xtensa/mm/mmu.c')
| -rw-r--r-- | arch/xtensa/mm/mmu.c | 104 |
1 files changed, 104 insertions, 0 deletions
diff --git a/arch/xtensa/mm/mmu.c b/arch/xtensa/mm/mmu.c new file mode 100644 index 00000000000..3429b483d9f --- /dev/null +++ b/arch/xtensa/mm/mmu.c @@ -0,0 +1,104 @@ +/* + * xtensa mmu stuff + * + * Extracted from init.c + */ +#include <linux/bootmem.h> +#include <linux/percpu.h> +#include <linux/init.h> +#include <linux/string.h> +#include <linux/slab.h> +#include <linux/cache.h> + +#include <asm/tlb.h> +#include <asm/tlbflush.h> +#include <asm/mmu_context.h> +#include <asm/page.h> +#include <asm/initialize_mmu.h> +#include <asm/io.h> + +#if defined(CONFIG_HIGHMEM) +static void * __init init_pmd(unsigned long vaddr) +{ + pgd_t *pgd = pgd_offset_k(vaddr); + pmd_t *pmd = pmd_offset(pgd, vaddr); + + if (pmd_none(*pmd)) { + unsigned i; + pte_t *pte = alloc_bootmem_low_pages(PAGE_SIZE); + + for (i = 0; i < 1024; i++) + pte_clear(NULL, 0, pte + i); + + set_pmd(pmd, __pmd(((unsigned long)pte) & PAGE_MASK)); + BUG_ON(pte != pte_offset_kernel(pmd, 0)); + pr_debug("%s: vaddr: 0x%08lx, pmd: 0x%p, pte: 0x%p\n", + __func__, vaddr, pmd, pte); + return pte; + } else { + return pte_offset_kernel(pmd, 0); + } +} + +static void __init fixedrange_init(void) +{ + BUILD_BUG_ON(FIXADDR_SIZE > PMD_SIZE); + init_pmd(__fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK); +} +#endif + +void __init paging_init(void) +{ + memset(swapper_pg_dir, 0, PAGE_SIZE); +#ifdef CONFIG_HIGHMEM + fixedrange_init(); + pkmap_page_table = init_pmd(PKMAP_BASE); + kmap_init(); +#endif +} + +/* + * Flush the mmu and reset associated register to default values. + */ +void init_mmu(void) +{ +#if !(XCHAL_HAVE_PTP_MMU && XCHAL_HAVE_SPANNING_WAY) + /* + * Writing zeros to the instruction and data TLBCFG special + * registers ensure that valid values exist in the register. + * + * For existing PGSZID<w> fields, zero selects the first element + * of the page-size array. For nonexistent PGSZID<w> fields, + * zero is the best value to write. Also, when changing PGSZID<w> + * fields, the corresponding TLB must be flushed. + */ + set_itlbcfg_register(0); + set_dtlbcfg_register(0); +#endif +#if XCHAL_HAVE_PTP_MMU && XCHAL_HAVE_SPANNING_WAY && defined(CONFIG_OF) + /* + * Update the IO area mapping in case xtensa_kio_paddr has changed + */ + write_dtlb_entry(__pte(xtensa_kio_paddr + CA_WRITEBACK), + XCHAL_KIO_CACHED_VADDR + 6); + write_itlb_entry(__pte(xtensa_kio_paddr + CA_WRITEBACK), + XCHAL_KIO_CACHED_VADDR + 6); + write_dtlb_entry(__pte(xtensa_kio_paddr + CA_BYPASS), + XCHAL_KIO_BYPASS_VADDR + 6); + write_itlb_entry(__pte(xtensa_kio_paddr + CA_BYPASS), + XCHAL_KIO_BYPASS_VADDR + 6); +#endif + + local_flush_tlb_all(); + + /* Set rasid register to a known value. */ + + set_rasid_register(ASID_INSERT(ASID_USER_FIRST)); + + /* Set PTEVADDR special register to the start of the page + * table, which is in kernel mappable space (ie. not + * statically mapped). This register's value is undefined on + * reset. + */ + set_ptevaddr_register(PGTABLE_START); +} |