| /* |
| * 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/bootmem.h> |
| #include <linux/types.h> |
| |
| #include <asm/addrspace.h> |
| #include <asm/bootinfo.h> |
| #include <asm/dec/machtype.h> |
| #include <asm/dec/prom.h> |
| #include <asm/page.h> |
| #include <asm/sections.h> |
| |
| |
| volatile unsigned long mem_err = 0; /* 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 inline 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); |
| |
| add_memory_region(0, (unsigned long)memory_page - CKSEG1 - CHUNK_SIZE, |
| BOOT_MEM_RAM); |
| } |
| |
| /* |
| * Use the REX prom calls to get hold of the memory bitmap, and thence |
| * determine memory size. |
| */ |
| static inline 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 { |
| add_memory_region(mem_start, mem_size, BOOT_MEM_RAM); |
| mem_start += mem_size + (8 * bm->pagesize); |
| mem_size = 0; |
| } |
| } |
| if (mem_size) |
| add_memory_region(mem_start, mem_size, BOOT_MEM_RAM); |
| } |
| |
| void __init prom_meminit(u32 magic) |
| { |
| if (!prom_is_rex(magic)) |
| pmax_setup_memory_region(); |
| else |
| rex_setup_memory_region(); |
| } |
| |
| unsigned long __init prom_free_prom_memory(void) |
| { |
| unsigned long addr, end; |
| |
| /* |
| * Free everything below the kernel itself but leave |
| * the first page reserved for the exception handlers. |
| */ |
| |
| #if defined(CONFIG_DECLANCE) || defined(CONFIG_DECLANCE_MODULE) |
| /* |
| * 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); |
| |
| addr = PAGE_SIZE; |
| while (addr < end) { |
| ClearPageReserved(virt_to_page(__va(addr))); |
| init_page_count(virt_to_page(__va(addr))); |
| free_page((unsigned long)__va(addr)); |
| addr += PAGE_SIZE; |
| } |
| |
| printk("Freeing unused PROM memory: %ldk freed\n", |
| (end - PAGE_SIZE) >> 10); |
| |
| return end - PAGE_SIZE; |
| } |