LXR linux/arch/cris/arch-v32/mm/init.c

   1/*
   2 * Set up paging and the MMU.
   3 *
   4 * Copyright (C) 2000-2003, Axis Communications AB.
   5 *
   6 * Authors:   Bjorn Wesen <bjornw@axis.com>
   7 *            Tobias Anderberg <tobiasa@axis.com>, CRISv32 port.
   8 */
   9#include <linux/mmzone.h>
  10#include <linux/init.h>
  11#include <linux/bootmem.h>
  12#include <linux/mm.h>
  13#include <asm/pgtable.h>
  14#include <asm/page.h>
  15#include <asm/types.h>
  16#include <asm/mmu.h>
  17#include <asm/io.h>
  18#include <asm/mmu_context.h>
  19#include <arch/hwregs/asm/mmu_defs_asm.h>
  20#include <arch/hwregs/supp_reg.h>
  21
  22extern void tlb_init(void);
  23
  24/*
  25 * The kernel is already mapped with linear mapping at kseg_c so there's no
  26 * need to map it with a page table. However, head.S also temporarily mapped it
  27 * at kseg_4 thus the ksegs are set up again. Also clear the TLB and do various
  28 * other paging stuff.
  29 */
  30void __init cris_mmu_init(void)
  31{
  32        unsigned long mmu_config;
  33        unsigned long mmu_kbase_hi;
  34        unsigned long mmu_kbase_lo;
  35        unsigned short mmu_page_id;
  36
  37        /*
  38         * Make sure the current pgd table points to something sane, even if it
  39         * is most probably not used until the next switch_mm.
  40         */
  41        per_cpu(current_pgd, smp_processor_id()) = init_mm.pgd;
  42
  43        /* Initialise the TLB. Function found in tlb.c. */
  44        tlb_init();
  45
  46        /*
  47         * Enable exceptions and initialize the kernel segments.
  48         * See head.S for differences between ARTPEC-3 and ETRAX FS.
  49         */
  50        mmu_config = ( REG_STATE(mmu, rw_mm_cfg, we, on)        |
  51                       REG_STATE(mmu, rw_mm_cfg, acc, on)       |
  52                       REG_STATE(mmu, rw_mm_cfg, ex, on)        |
  53                       REG_STATE(mmu, rw_mm_cfg, inv, on)       |
  54#ifdef CONFIG_CRIS_MACH_ARTPEC3
  55                       REG_STATE(mmu, rw_mm_cfg, seg_f, page)   |
  56                       REG_STATE(mmu, rw_mm_cfg, seg_e, page)   |
  57                       REG_STATE(mmu, rw_mm_cfg, seg_d, linear) |
  58#else
  59                       REG_STATE(mmu, rw_mm_cfg, seg_f, linear) |
  60                       REG_STATE(mmu, rw_mm_cfg, seg_e, linear) |
  61                       REG_STATE(mmu, rw_mm_cfg, seg_d, page)   |
  62#endif
  63                       REG_STATE(mmu, rw_mm_cfg, seg_c, linear) |
  64                       REG_STATE(mmu, rw_mm_cfg, seg_b, linear) |
  65                       REG_STATE(mmu, rw_mm_cfg, seg_a, page)   |
  66                       REG_STATE(mmu, rw_mm_cfg, seg_9, page)   |
  67                       REG_STATE(mmu, rw_mm_cfg, seg_8, page)   |
  68                       REG_STATE(mmu, rw_mm_cfg, seg_7, page)   |
  69                       REG_STATE(mmu, rw_mm_cfg, seg_6, page)   |
  70                       REG_STATE(mmu, rw_mm_cfg, seg_5, page)   |
  71                       REG_STATE(mmu, rw_mm_cfg, seg_4, page)   |
  72                       REG_STATE(mmu, rw_mm_cfg, seg_3, page)   |
  73                       REG_STATE(mmu, rw_mm_cfg, seg_2, page)   |
  74                       REG_STATE(mmu, rw_mm_cfg, seg_1, page)   |
  75                       REG_STATE(mmu, rw_mm_cfg, seg_0, page));
  76
  77        /* See head.S for differences between ARTPEC-3 and ETRAX FS. */
  78        mmu_kbase_hi = ( REG_FIELD(mmu, rw_mm_kbase_hi, base_f, 0x0) |
  79#ifdef CONFIG_CRIS_MACH_ARTPEC3
  80                         REG_FIELD(mmu, rw_mm_kbase_hi, base_e, 0x0) |
  81                         REG_FIELD(mmu, rw_mm_kbase_hi, base_d, 0x5) |
  82#else
  83                         REG_FIELD(mmu, rw_mm_kbase_hi, base_e, 0x8) |
  84                         REG_FIELD(mmu, rw_mm_kbase_hi, base_d, 0x0) |
  85#endif
  86                         REG_FIELD(mmu, rw_mm_kbase_hi, base_c, 0x4) |
  87                         REG_FIELD(mmu, rw_mm_kbase_hi, base_b, 0xb) |
  88                         REG_FIELD(mmu, rw_mm_kbase_hi, base_a, 0x0) |
  89                         REG_FIELD(mmu, rw_mm_kbase_hi, base_9, 0x0) |
  90                         REG_FIELD(mmu, rw_mm_kbase_hi, base_8, 0x0));
  91
  92        mmu_kbase_lo = ( REG_FIELD(mmu, rw_mm_kbase_lo, base_7, 0x0) |
  93                         REG_FIELD(mmu, rw_mm_kbase_lo, base_6, 0x0) |
  94                         REG_FIELD(mmu, rw_mm_kbase_lo, base_5, 0x0) |
  95                         REG_FIELD(mmu, rw_mm_kbase_lo, base_4, 0x0) |
  96                         REG_FIELD(mmu, rw_mm_kbase_lo, base_3, 0x0) |
  97                         REG_FIELD(mmu, rw_mm_kbase_lo, base_2, 0x0) |
  98                         REG_FIELD(mmu, rw_mm_kbase_lo, base_1, 0x0) |
  99                         REG_FIELD(mmu, rw_mm_kbase_lo, base_0, 0x0));
 100
 101        mmu_page_id = REG_FIELD(mmu, rw_mm_tlb_hi, pid, 0);
 102
 103        /* Update the instruction MMU. */
 104        SUPP_BANK_SEL(BANK_IM);
 105        SUPP_REG_WR(RW_MM_CFG, mmu_config);
 106        SUPP_REG_WR(RW_MM_KBASE_HI, mmu_kbase_hi);
 107        SUPP_REG_WR(RW_MM_KBASE_LO, mmu_kbase_lo);
 108        SUPP_REG_WR(RW_MM_TLB_HI, mmu_page_id);
 109
 110        /* Update the data MMU. */
 111        SUPP_BANK_SEL(BANK_DM);
 112        SUPP_REG_WR(RW_MM_CFG, mmu_config);
 113        SUPP_REG_WR(RW_MM_KBASE_HI, mmu_kbase_hi);
 114        SUPP_REG_WR(RW_MM_KBASE_LO, mmu_kbase_lo);
 115        SUPP_REG_WR(RW_MM_TLB_HI, mmu_page_id);
 116
 117        SPEC_REG_WR(SPEC_REG_PID, 0);
 118
 119        /*
 120         * The MMU has been enabled ever since head.S but just to make it
 121         * totally obvious enable it here as well.
 122         */
 123        SUPP_BANK_SEL(BANK_GC);
 124        SUPP_REG_WR(RW_GC_CFG, 0xf); /* IMMU, DMMU, ICache, DCache on */
 125}
 126
 127void __init paging_init(void)
 128{
 129        int i;
 130        unsigned long zones_size[MAX_NR_ZONES];
 131
 132        printk("Setting up paging and the MMU.\n");
 133
 134        /* Clear out the init_mm.pgd that will contain the kernel's mappings. */
 135        for(i = 0; i < PTRS_PER_PGD; i++)
 136                swapper_pg_dir[i] = __pgd(0);
 137
 138        cris_mmu_init();
 139
 140        /*
 141         * Initialize the bad page table and bad page to point to a couple of
 142         * allocated pages.
 143         */
 144        empty_zero_page = (unsigned long) alloc_bootmem_pages(PAGE_SIZE);
 145        memset((void *) empty_zero_page, 0, PAGE_SIZE);
 146
 147        /* All pages are DMA'able in Etrax, so put all in the DMA'able zone. */
 148        zones_size[0] = ((unsigned long) high_memory - PAGE_OFFSET) >> PAGE_SHIFT;
 149
 150        for (i = 1; i < MAX_NR_ZONES; i++)
 151                zones_size[i] = 0;
 152
 153        /*
 154         * Use free_area_init_node instead of free_area_init, because it is
 155         * designed for systems where the DRAM starts at an address
 156         * substantially higher than 0, like us (we start at PAGE_OFFSET). This
 157         * saves space in the mem_map page array.
 158         */
 159        free_area_init_node(0, zones_size, PAGE_OFFSET >> PAGE_SHIFT, 0);
 160
 161        mem_map = contig_page_data.node_mem_map;
 162}
 163