arch/powerpc/mm/44x_mmu.c

   1 /*
   2  * Modifications by Matt Porter (mporter@mvista.com) to support
   3  * PPC44x Book E processors.
   4  *
   5  * This file contains the routines for initializing the MMU
   6  * on the 4xx series of chips.
   7  *  -- paulus
   8  *
   9  *  Derived from arch/ppc/mm/init.c:
  10  *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
  11  *
  12  *  Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au)
  13  *  and Cort Dougan (PReP) (cort@cs.nmt.edu)
  14  *    Copyright (C) 1996 Paul Mackerras
  15  *
  16  *  Derived from "arch/i386/mm/init.c"
  17  *    Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
  18  *
  19  *  This program is free software; you can redistribute it and/or
  20  *  modify it under the terms of the GNU General Public License
  21  *  as published by the Free Software Foundation; either version
  22  *  2 of the License, or (at your option) any later version.
  23  *
  24  */
  25
  26 #include <linux/init.h>
  27 #include <linux/memblock.h>
  28
  29 #include <asm/mmu.h>
  30 #include <asm/system.h>
  31 #include <asm/page.h>
  32 #include <asm/cacheflush.h>
  33
  34 #include "mmu_decl.h"
  35
  36 /* Used by the 44x TLB replacement exception handler.
  37  * Just needed it declared someplace.
  38  */
  39 unsigned int tlb_44x_index; /* = 0 */
  40 unsigned int tlb_44x_hwater = PPC44x_TLB_SIZE - 1 - PPC44x_EARLY_TLBS;
  41 int icache_44x_need_flush;
  42
  43 unsigned long tlb_47x_boltmap[1024/8];
  44
  45 static void __cpuinit ppc44x_update_tlb_hwater(void)
  46 {
  47         extern unsigned int tlb_44x_patch_hwater_D[];
  48         extern unsigned int tlb_44x_patch_hwater_I[];
  49
  50         /* The TLB miss handlers hard codes the watermark in a cmpli
  51          * instruction to improve performances rather than loading it
  52          * from the global variable. Thus, we patch the instructions
  53          * in the 2 TLB miss handlers when updating the value
  54          */
  55         tlb_44x_patch_hwater_D[0] = (tlb_44x_patch_hwater_D[0] & 0xffff0000) |
  56                 tlb_44x_hwater;
  57         flush_icache_range((unsigned long)&tlb_44x_patch_hwater_D[0],
  58                            (unsigned long)&tlb_44x_patch_hwater_D[1]);
  59         tlb_44x_patch_hwater_I[0] = (tlb_44x_patch_hwater_I[0] & 0xffff0000) |
  60                 tlb_44x_hwater;
  61         flush_icache_range((unsigned long)&tlb_44x_patch_hwater_I[0],
  62                            (unsigned long)&tlb_44x_patch_hwater_I[1]);
  63 }
  64
  65 /*
  66  * "Pins" a 256MB TLB entry in AS0 for kernel lowmem for 44x type MMU
  67  */
  68 static void __init ppc44x_pin_tlb(unsigned int virt, unsigned int phys)
  69 {
  70         unsigned int entry = tlb_44x_hwater--;
  71
  72         ppc44x_update_tlb_hwater();
  73
  74         mtspr(SPRN_MMUCR, 0);
  75
  76         __asm__ __volatile__(
  77                 "tlbwe  %2,%3,%4\n"
  78                 "tlbwe  %1,%3,%5\n"
  79                 "tlbwe  %0,%3,%6\n"
  80         :
  81 #ifdef CONFIG_PPC47x
  82         : "r" (PPC47x_TLB2_S_RWX),
  83 #else
  84         : "r" (PPC44x_TLB_SW | PPC44x_TLB_SR | PPC44x_TLB_SX | PPC44x_TLB_G),
  85 #endif
  86           "r" (phys),
  87           "r" (virt | PPC44x_TLB_VALID | PPC44x_TLB_256M),
  88           "r" (entry),
  89           "i" (PPC44x_TLB_PAGEID),
  90           "i" (PPC44x_TLB_XLAT),
  91           "i" (PPC44x_TLB_ATTRIB));
  92 }
  93
  94 static int __init ppc47x_find_free_bolted(void)
  95 {
  96         unsigned int mmube0 = mfspr(SPRN_MMUBE0);
  97         unsigned int mmube1 = mfspr(SPRN_MMUBE1);
  98
  99         if (!(mmube0 & MMUBE0_VBE0))
 100                 return 0;
 101         if (!(mmube0 & MMUBE0_VBE1))
 102                 return 1;
 103         if (!(mmube0 & MMUBE0_VBE2))
 104                 return 2;
 105         if (!(mmube1 & MMUBE1_VBE3))
 106                 return 3;
 107         if (!(mmube1 & MMUBE1_VBE4))
 108                 return 4;
 109         if (!(mmube1 & MMUBE1_VBE5))
 110                 return 5;
 111         return -1;
 112 }
 113
 114 static void __init ppc47x_update_boltmap(void)
 115 {
 116         unsigned int mmube0 = mfspr(SPRN_MMUBE0);
 117         unsigned int mmube1 = mfspr(SPRN_MMUBE1);
 118
 119         if (mmube0 & MMUBE0_VBE0)
 120                 __set_bit((mmube0 >> MMUBE0_IBE0_SHIFT) & 0xff,
 121                           tlb_47x_boltmap);
 122         if (mmube0 & MMUBE0_VBE1)
 123                 __set_bit((mmube0 >> MMUBE0_IBE1_SHIFT) & 0xff,
 124                           tlb_47x_boltmap);
 125         if (mmube0 & MMUBE0_VBE2)
 126                 __set_bit((mmube0 >> MMUBE0_IBE2_SHIFT) & 0xff,
 127                           tlb_47x_boltmap);
 128         if (mmube1 & MMUBE1_VBE3)
 129                 __set_bit((mmube1 >> MMUBE1_IBE3_SHIFT) & 0xff,
 130                           tlb_47x_boltmap);
 131         if (mmube1 & MMUBE1_VBE4)
 132                 __set_bit((mmube1 >> MMUBE1_IBE4_SHIFT) & 0xff,
 133                           tlb_47x_boltmap);
 134         if (mmube1 & MMUBE1_VBE5)
 135                 __set_bit((mmube1 >> MMUBE1_IBE5_SHIFT) & 0xff,
 136                           tlb_47x_boltmap);
 137 }
 138
 139 /*
 140  * "Pins" a 256MB TLB entry in AS0 for kernel lowmem for 47x type MMU
 141  */
 142 static void __cpuinit ppc47x_pin_tlb(unsigned int virt, unsigned int phys)
 143 {
 144         unsigned int rA;
 145         int bolted;
 146
 147         /* Base rA is HW way select, way 0, bolted bit set */
 148         rA = 0x88000000;
 149
 150         /* Look for a bolted entry slot */
 151         bolted = ppc47x_find_free_bolted();
 152         BUG_ON(bolted < 0);
 153
 154         /* Insert bolted slot number */
 155         rA |= bolted << 24;
 156
 157         pr_debug("256M TLB entry for 0x%08x->0x%08x in bolt slot %d\n",
 158                  virt, phys, bolted);
 159
 160         mtspr(SPRN_MMUCR, 0);
 161
 162         __asm__ __volatile__(
 163                 "tlbwe  %2,%3,0\n"
 164                 "tlbwe  %1,%3,1\n"
 165                 "tlbwe  %0,%3,2\n"
 166                 :
 167                 : "r" (PPC47x_TLB2_SW | PPC47x_TLB2_SR |
 168                        PPC47x_TLB2_SX
 169 #ifdef CONFIG_SMP
 170                        | PPC47x_TLB2_M
 171 #endif
 172                        ),
 173                   "r" (phys),
 174                   "r" (virt | PPC47x_TLB0_VALID | PPC47x_TLB0_256M),
 175                   "r" (rA));
 176 }
 177
 178 void __init MMU_init_hw(void)
 179 {
 180         /* This is not useful on 47x but won't hurt either */
 181         ppc44x_update_tlb_hwater();
 182
 183         flush_instruction_cache();
 184 }
 185
 186 unsigned long __init mmu_mapin_ram(unsigned long top)
 187 {
 188         unsigned long addr;
 189
 190         /* Pin in enough TLBs to cover any lowmem not covered by the
 191          * initial 256M mapping established in head_44x.S */
 192         for (addr = PPC_PIN_SIZE; addr < lowmem_end_addr;
 193              addr += PPC_PIN_SIZE) {
 194                 if (mmu_has_feature(MMU_FTR_TYPE_47x))
 195                         ppc47x_pin_tlb(addr + PAGE_OFFSET, addr);
 196                 else
 197                         ppc44x_pin_tlb(addr + PAGE_OFFSET, addr);
 198         }
 199         if (mmu_has_feature(MMU_FTR_TYPE_47x)) {
 200                 ppc47x_update_boltmap();
 201
 202 #ifdef DEBUG
 203                 {
 204                         int i;
 205
 206                         printk(KERN_DEBUG "bolted entries: ");
 207                         for (i = 0; i < 255; i++) {
 208                                 if (test_bit(i, tlb_47x_boltmap))
 209                                         printk("%d ", i);
 210                         }
 211                         printk("\n");
 212                 }
 213 #endif /* DEBUG */
 214         }
 215         return total_lowmem;
 216 }
 217
 218 void setup_initial_memory_limit(phys_addr_t first_memblock_base,
 219                                 phys_addr_t first_memblock_size)
 220 {
 221         /* We don't currently support the first MEMBLOCK not mapping 0
 222          * physical on those processors
 223          */
 224         BUG_ON(first_memblock_base != 0);
 225
 226         /* 44x has a 256M TLB entry pinned at boot */
 227         memblock_set_current_limit(min_t(u64, first_memblock_size, PPC_PIN_SIZE));
 228 }
 229
 230 #ifdef CONFIG_SMP
 231 void __cpuinit mmu_init_secondary(int cpu)
 232 {
 233         unsigned long addr;
 234
 235         /* Pin in enough TLBs to cover any lowmem not covered by the
 236          * initial 256M mapping established in head_44x.S
 237          *
 238          * WARNING: This is called with only the first 256M of the
 239          * linear mapping in the TLB and we can't take faults yet
 240          * so beware of what this code uses. It runs off a temporary
 241          * stack. current (r2) isn't initialized, smp_processor_id()
 242          * will not work, current thread info isn't accessible, ...
 243          */
 244         for (addr = PPC_PIN_SIZE; addr < lowmem_end_addr;
 245              addr += PPC_PIN_SIZE) {
 246                 if (mmu_has_feature(MMU_FTR_TYPE_47x))
 247                         ppc47x_pin_tlb(addr + PAGE_OFFSET, addr);
 248                 else
 249                         ppc44x_pin_tlb(addr + PAGE_OFFSET, addr);
 250         }
 251 }
 252 #endif /* CONFIG_SMP */