2 * This file contains the routines for initializing the MMU
3 * on the 8xx series of chips.
6 * Derived from arch/powerpc/mm/40x_mmu.c:
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License
10 * as published by the Free Software Foundation; either version
11 * 2 of the License, or (at your option) any later version.
15 #include <linux/memblock.h>
16 #include <asm/fixmap.h>
17 #include <asm/code-patching.h>
21 #define IMMR_SIZE (FIX_IMMR_SIZE << PAGE_SHIFT)
23 extern int __map_without_ltlbs;
26 * Return PA for this VA if it is in IMMR area, or 0
28 phys_addr_t v_block_mapped(unsigned long va)
30 unsigned long p = PHYS_IMMR_BASE;
32 if (__map_without_ltlbs)
34 if (va >= VIRT_IMMR_BASE && va < VIRT_IMMR_BASE + IMMR_SIZE)
35 return p + va - VIRT_IMMR_BASE;
40 * Return VA for a given PA or 0 if not mapped
42 unsigned long p_block_mapped(phys_addr_t pa)
44 unsigned long p = PHYS_IMMR_BASE;
46 if (__map_without_ltlbs)
48 if (pa >= p && pa < p + IMMR_SIZE)
49 return VIRT_IMMR_BASE + pa - p;
54 * MMU_init_hw does the chip-specific initialization of the MMU hardware.
56 void __init MMU_init_hw(void)
58 /* Nothing to do for the time being but keep it similar to other PPC */
61 #define LARGE_PAGE_SIZE_4M (1<<22)
62 #define LARGE_PAGE_SIZE_8M (1<<23)
63 #define LARGE_PAGE_SIZE_64M (1<<26)
65 static void mmu_mapin_immr(void)
67 unsigned long p = PHYS_IMMR_BASE;
68 unsigned long v = VIRT_IMMR_BASE;
69 unsigned long f = pgprot_val(PAGE_KERNEL_NCG);
72 for (offset = 0; offset < IMMR_SIZE; offset += PAGE_SIZE)
73 map_page(v + offset, p + offset, f);
76 /* Address of instructions to patch */
77 #ifndef CONFIG_PIN_TLB
78 extern unsigned int DTLBMiss_jmp;
81 unsigned long __init mmu_mapin_ram(unsigned long top)
83 unsigned long v, s, mapped;
90 if (__map_without_ltlbs) {
92 #ifndef CONFIG_PIN_TLB
93 patch_instruction(&DTLBMiss_jmp, PPC_INST_NOP);
98 #ifdef CONFIG_PPC_4K_PAGES
99 while (s >= LARGE_PAGE_SIZE_8M) {
101 unsigned long val = p | MD_PS8MEG;
103 pmdp = pmd_offset(pud_offset(pgd_offset_k(v), v), v);
104 *pmdp++ = __pmd(val);
105 *pmdp++ = __pmd(val + LARGE_PAGE_SIZE_4M);
107 v += LARGE_PAGE_SIZE_8M;
108 p += LARGE_PAGE_SIZE_8M;
109 s -= LARGE_PAGE_SIZE_8M;
111 #else /* CONFIG_PPC_16K_PAGES */
112 while (s >= LARGE_PAGE_SIZE_64M) {
114 unsigned long val = p | MD_PS8MEG;
116 pmdp = pmd_offset(pud_offset(pgd_offset_k(v), v), v);
117 *pmdp++ = __pmd(val);
119 v += LARGE_PAGE_SIZE_64M;
120 p += LARGE_PAGE_SIZE_64M;
121 s -= LARGE_PAGE_SIZE_64M;
127 /* If the size of RAM is not an exact power of two, we may not
128 * have covered RAM in its entirety with 8 MiB
129 * pages. Consequently, restrict the top end of RAM currently
130 * allocable so that calls to the MEMBLOCK to allocate PTEs for "tail"
131 * coverage with normal-sized pages (or other reasons) do not
132 * attempt to allocate outside the allowed range.
134 memblock_set_current_limit(mapped);
139 void setup_initial_memory_limit(phys_addr_t first_memblock_base,
140 phys_addr_t first_memblock_size)
142 /* We don't currently support the first MEMBLOCK not mapping 0
143 * physical on those processors
145 BUG_ON(first_memblock_base != 0);
147 #ifdef CONFIG_PIN_TLB
148 /* 8xx can only access 24MB at the moment */
149 memblock_set_current_limit(min_t(u64, first_memblock_size, 0x01800000));
151 /* 8xx can only access 8MB at the moment */
152 memblock_set_current_limit(min_t(u64, first_memblock_size, 0x00800000));
157 * Set up to use a given MMU context.
158 * id is context number, pgd is PGD pointer.
160 * We place the physical address of the new task page directory loaded
161 * into the MMU base register, and set the ASID compare register with
164 void set_context(unsigned long id, pgd_t *pgd)
166 s16 offset = (s16)(__pa(swapper_pg_dir));
168 #ifdef CONFIG_BDI_SWITCH
169 pgd_t **ptr = *(pgd_t ***)(KERNELBASE + 0xf0);
171 /* Context switch the PTE pointer for the Abatron BDI2000.
172 * The PGDIR is passed as second argument.
177 /* Register M_TW will contain base address of level 1 table minus the
178 * lower part of the kernel PGDIR base address, so that all accesses to
179 * level 1 table are done relative to lower part of kernel PGDIR base
182 mtspr(SPRN_M_TW, __pa(pgd) - offset);
185 mtspr(SPRN_M_CASID, id);
190 void flush_instruction_cache(void)
193 mtspr(SPRN_IC_CST, IDC_INVALL);