1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Modifications by Matt Porter (mporter@mvista.com) to support 4 * PPC44x Book E processors. 5 * 6 * This file contains the routines for initializing the MMU 7 * on the 4xx series of chips. 8 * -- paulus 9 * 10 * Derived from arch/ppc/mm/init.c: 11 * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org) 12 * 13 * Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au) 14 * and Cort Dougan (PReP) (cort@cs.nmt.edu) 15 * Copyright (C) 1996 Paul Mackerras 16 * 17 * Derived from "arch/i386/mm/init.c" 18 * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds 19 */ 20 21 #include <linux/init.h> 22 #include <linux/memblock.h> 23 24 #include <asm/mmu.h> 25 #include <asm/page.h> 26 #include <asm/cacheflush.h> 27 #include <asm/text-patching.h> 28 #include <asm/smp.h> 29 30 #include <mm/mmu_decl.h> 31 32 /* Used by the 44x TLB replacement exception handler. 33 * Just needed it declared someplace. 34 */ 35 unsigned int tlb_44x_index; /* = 0 */ 36 unsigned int tlb_44x_hwater = PPC44x_TLB_SIZE - 1 - PPC44x_EARLY_TLBS; 37 int icache_44x_need_flush; 38 39 unsigned long tlb_47x_boltmap[1024/8]; 40 41 static void __init ppc44x_update_tlb_hwater(void) 42 { 43 /* The TLB miss handlers hard codes the watermark in a cmpli 44 * instruction to improve performances rather than loading it 45 * from the global variable. Thus, we patch the instructions 46 * in the 2 TLB miss handlers when updating the value 47 */ 48 modify_instruction_site(&patch__tlb_44x_hwater_D, 0xffff, tlb_44x_hwater); 49 modify_instruction_site(&patch__tlb_44x_hwater_I, 0xffff, tlb_44x_hwater); 50 } 51 52 /* 53 * "Pins" a 256MB TLB entry in AS0 for kernel lowmem for 44x type MMU 54 */ 55 static void __init ppc44x_pin_tlb(unsigned int virt, unsigned int phys) 56 { 57 unsigned int entry = tlb_44x_hwater--; 58 59 ppc44x_update_tlb_hwater(); 60 61 mtspr(SPRN_MMUCR, 0); 62 63 __asm__ __volatile__( 64 "tlbwe %2,%3,%4\n" 65 "tlbwe %1,%3,%5\n" 66 "tlbwe %0,%3,%6\n" 67 : 68 : "r" (PPC44x_TLB_SW | PPC44x_TLB_SR | PPC44x_TLB_SX | PPC44x_TLB_G), 69 "r" (phys), 70 "r" (virt | PPC44x_TLB_VALID | PPC44x_TLB_256M), 71 "r" (entry), 72 "i" (PPC44x_TLB_PAGEID), 73 "i" (PPC44x_TLB_XLAT), 74 "i" (PPC44x_TLB_ATTRIB)); 75 } 76 77 static int __init ppc47x_find_free_bolted(void) 78 { 79 unsigned int mmube0 = mfspr(SPRN_MMUBE0); 80 unsigned int mmube1 = mfspr(SPRN_MMUBE1); 81 82 if (!(mmube0 & MMUBE0_VBE0)) 83 return 0; 84 if (!(mmube0 & MMUBE0_VBE1)) 85 return 1; 86 if (!(mmube0 & MMUBE0_VBE2)) 87 return 2; 88 if (!(mmube1 & MMUBE1_VBE3)) 89 return 3; 90 if (!(mmube1 & MMUBE1_VBE4)) 91 return 4; 92 if (!(mmube1 & MMUBE1_VBE5)) 93 return 5; 94 return -1; 95 } 96 97 static void __init ppc47x_update_boltmap(void) 98 { 99 unsigned int mmube0 = mfspr(SPRN_MMUBE0); 100 unsigned int mmube1 = mfspr(SPRN_MMUBE1); 101 102 if (mmube0 & MMUBE0_VBE0) 103 __set_bit((mmube0 >> MMUBE0_IBE0_SHIFT) & 0xff, 104 tlb_47x_boltmap); 105 if (mmube0 & MMUBE0_VBE1) 106 __set_bit((mmube0 >> MMUBE0_IBE1_SHIFT) & 0xff, 107 tlb_47x_boltmap); 108 if (mmube0 & MMUBE0_VBE2) 109 __set_bit((mmube0 >> MMUBE0_IBE2_SHIFT) & 0xff, 110 tlb_47x_boltmap); 111 if (mmube1 & MMUBE1_VBE3) 112 __set_bit((mmube1 >> MMUBE1_IBE3_SHIFT) & 0xff, 113 tlb_47x_boltmap); 114 if (mmube1 & MMUBE1_VBE4) 115 __set_bit((mmube1 >> MMUBE1_IBE4_SHIFT) & 0xff, 116 tlb_47x_boltmap); 117 if (mmube1 & MMUBE1_VBE5) 118 __set_bit((mmube1 >> MMUBE1_IBE5_SHIFT) & 0xff, 119 tlb_47x_boltmap); 120 } 121 122 /* 123 * "Pins" a 256MB TLB entry in AS0 for kernel lowmem for 47x type MMU 124 */ 125 static void __init ppc47x_pin_tlb(unsigned int virt, unsigned int phys) 126 { 127 unsigned int rA; 128 int bolted; 129 130 /* Base rA is HW way select, way 0, bolted bit set */ 131 rA = 0x88000000; 132 133 /* Look for a bolted entry slot */ 134 bolted = ppc47x_find_free_bolted(); 135 BUG_ON(bolted < 0); 136 137 /* Insert bolted slot number */ 138 rA |= bolted << 24; 139 140 pr_debug("256M TLB entry for 0x%08x->0x%08x in bolt slot %d\n", 141 virt, phys, bolted); 142 143 mtspr(SPRN_MMUCR, 0); 144 145 __asm__ __volatile__( 146 "tlbwe %2,%3,0\n" 147 "tlbwe %1,%3,1\n" 148 "tlbwe %0,%3,2\n" 149 : 150 : "r" (PPC47x_TLB2_SW | PPC47x_TLB2_SR | 151 PPC47x_TLB2_SX 152 #ifdef CONFIG_SMP 153 | PPC47x_TLB2_M 154 #endif 155 ), 156 "r" (phys), 157 "r" (virt | PPC47x_TLB0_VALID | PPC47x_TLB0_256M), 158 "r" (rA)); 159 } 160 161 void __init MMU_init_hw(void) 162 { 163 /* This is not useful on 47x but won't hurt either */ 164 ppc44x_update_tlb_hwater(); 165 166 flush_instruction_cache(); 167 } 168 169 unsigned long __init mmu_mapin_ram(unsigned long base, unsigned long top) 170 { 171 unsigned long addr; 172 unsigned long memstart = memstart_addr & ~(PPC_PIN_SIZE - 1); 173 174 /* Pin in enough TLBs to cover any lowmem not covered by the 175 * initial 256M mapping established in head_44x.S */ 176 for (addr = memstart + PPC_PIN_SIZE; addr < lowmem_end_addr; 177 addr += PPC_PIN_SIZE) { 178 if (mmu_has_feature(MMU_FTR_TYPE_47x)) 179 ppc47x_pin_tlb(addr + PAGE_OFFSET, addr); 180 else 181 ppc44x_pin_tlb(addr + PAGE_OFFSET, addr); 182 } 183 if (mmu_has_feature(MMU_FTR_TYPE_47x)) { 184 ppc47x_update_boltmap(); 185 186 #ifdef DEBUG 187 { 188 int i; 189 190 printk(KERN_DEBUG "bolted entries: "); 191 for (i = 0; i < 255; i++) { 192 if (test_bit(i, tlb_47x_boltmap)) 193 printk("%d ", i); 194 } 195 printk("\n"); 196 } 197 #endif /* DEBUG */ 198 } 199 return total_lowmem; 200 } 201 202 void setup_initial_memory_limit(phys_addr_t first_memblock_base, 203 phys_addr_t first_memblock_size) 204 { 205 u64 size; 206 207 #ifndef CONFIG_NONSTATIC_KERNEL 208 /* We don't currently support the first MEMBLOCK not mapping 0 209 * physical on those processors 210 */ 211 BUG_ON(first_memblock_base != 0); 212 #endif 213 214 /* 44x has a 256M TLB entry pinned at boot */ 215 size = (min_t(u64, first_memblock_size, PPC_PIN_SIZE)); 216 memblock_set_current_limit(first_memblock_base + size); 217 } 218 219 #ifdef CONFIG_SMP 220 void __init mmu_init_secondary(int cpu) 221 { 222 unsigned long addr; 223 unsigned long memstart = memstart_addr & ~(PPC_PIN_SIZE - 1); 224 225 /* Pin in enough TLBs to cover any lowmem not covered by the 226 * initial 256M mapping established in head_44x.S 227 * 228 * WARNING: This is called with only the first 256M of the 229 * linear mapping in the TLB and we can't take faults yet 230 * so beware of what this code uses. It runs off a temporary 231 * stack. current (r2) isn't initialized, smp_processor_id() 232 * will not work, current thread info isn't accessible, ... 233 */ 234 for (addr = memstart + PPC_PIN_SIZE; addr < lowmem_end_addr; 235 addr += PPC_PIN_SIZE) { 236 if (mmu_has_feature(MMU_FTR_TYPE_47x)) 237 ppc47x_pin_tlb(addr + PAGE_OFFSET, addr); 238 else 239 ppc44x_pin_tlb(addr + PAGE_OFFSET, addr); 240 } 241 } 242 #endif /* CONFIG_SMP */ 243