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/code-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
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