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