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Diffstat (limited to 'arch/mips/dec/prom/memory.c')
| -rw-r--r-- | arch/mips/dec/prom/memory.c | 118 |
1 files changed, 118 insertions, 0 deletions
diff --git a/arch/mips/dec/prom/memory.c b/arch/mips/dec/prom/memory.c new file mode 100644 index 000000000..8c62316f2 --- /dev/null +++ b/arch/mips/dec/prom/memory.c @@ -0,0 +1,118 @@ +/* + * 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; /* 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(); +} + +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); +} |