Loading...
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 | // SPDX-License-Identifier: GPL-2.0 /* * memory.c: memory initialisation code. * * Copyright (C) 1998 Harald Koerfgen, Frieder Streffer and Paul M. Antoine * Copyright (C) 2000, 2002 Maciej W. Rozycki */ #include <linux/init.h> #include <linux/kernel.h> #include <linux/mm.h> #include <linux/memblock.h> #include <linux/types.h> #include <asm/addrspace.h> #include <asm/dec/machtype.h> #include <asm/dec/prom.h> #include <asm/page.h> #include <asm/sections.h> volatile unsigned long mem_err; /* So we know an error occurred */ /* * Probe memory in 4MB chunks, waiting for an error to tell us we've fallen * off the end of real memory. Only suitable for the 2100/3100's (PMAX). */ #define CHUNK_SIZE 0x400000 static __init void pmax_setup_memory_region(void) { volatile unsigned char *memory_page, dummy; char old_handler[0x80]; extern char genexcept_early; /* Install exception handler */ memcpy(&old_handler, (void *)(CKSEG0 + 0x80), 0x80); memcpy((void *)(CKSEG0 + 0x80), &genexcept_early, 0x80); /* read unmapped and uncached (KSEG1) * DECstations have at least 4MB RAM * Assume less than 480MB of RAM, as this is max for 5000/2xx * FIXME this should be replaced by the first free page! */ for (memory_page = (unsigned char *)CKSEG1 + CHUNK_SIZE; mem_err == 0 && memory_page < (unsigned char *)CKSEG1 + 0x1e00000; memory_page += CHUNK_SIZE) { dummy = *memory_page; } memcpy((void *)(CKSEG0 + 0x80), &old_handler, 0x80); memblock_add(0, (unsigned long)memory_page - CKSEG1 - CHUNK_SIZE); } /* * Use the REX prom calls to get hold of the memory bitmap, and thence * determine memory size. */ static __init void rex_setup_memory_region(void) { int i, bitmap_size; unsigned long mem_start = 0, mem_size = 0; memmap *bm; /* some free 64k */ bm = (memmap *)CKSEG0ADDR(0x28000); bitmap_size = rex_getbitmap(bm); for (i = 0; i < bitmap_size; i++) { /* FIXME: very simplistically only add full sets of pages */ if (bm->bitmap[i] == 0xff) mem_size += (8 * bm->pagesize); else if (!mem_size) mem_start += (8 * bm->pagesize); else { memblock_add(mem_start, mem_size); mem_start += mem_size + (8 * bm->pagesize); mem_size = 0; } } if (mem_size) memblock_add(mem_start, mem_size); } void __init prom_meminit(u32 magic) { if (!prom_is_rex(magic)) pmax_setup_memory_region(); else rex_setup_memory_region(); } void __init prom_free_prom_memory(void) { unsigned long end; /* * Free everything below the kernel itself but leave * the first page reserved for the exception handlers. */ #if IS_ENABLED(CONFIG_DECLANCE) /* * Leave 128 KB reserved for Lance memory for * IOASIC DECstations. * * XXX: save this address for use in dec_lance.c? */ if (IOASIC) end = __pa(&_text) - 0x00020000; else #endif end = __pa(&_text); free_init_pages("unused PROM memory", PAGE_SIZE, end); } |