2 * memory.c: memory initialisation code.
4 * Copyright (C) 1998 Harald Koerfgen, Frieder Streffer and Paul M. Antoine
5 * Copyright (C) 2000, 2002 Maciej W. Rozycki
7 #include <linux/config.h>
8 #include <linux/init.h>
9 #include <linux/kernel.h>
11 #include <linux/bootmem.h>
12 #include <linux/types.h>
14 #include <asm/addrspace.h>
15 #include <asm/bootinfo.h>
16 #include <asm/dec/machtype.h>
17 #include <asm/dec/prom.h>
19 #include <asm/sections.h>
22 volatile unsigned long mem_err
= 0; /* So we know an error occurred */
25 * Probe memory in 4MB chunks, waiting for an error to tell us we've fallen
26 * off the end of real memory. Only suitable for the 2100/3100's (PMAX).
29 #define CHUNK_SIZE 0x400000
31 static inline void pmax_setup_memory_region(void)
33 volatile unsigned char *memory_page
, dummy
;
34 char old_handler
[0x80];
35 extern char genexcept_early
;
37 /* Install exception handler */
38 memcpy(&old_handler
, (void *)(CKSEG0
+ 0x80), 0x80);
39 memcpy((void *)(CKSEG0
+ 0x80), &genexcept_early
, 0x80);
41 /* read unmapped and uncached (KSEG1)
42 * DECstations have at least 4MB RAM
43 * Assume less than 480MB of RAM, as this is max for 5000/2xx
44 * FIXME this should be replaced by the first free page!
46 for (memory_page
= (unsigned char *)CKSEG1
+ CHUNK_SIZE
;
47 mem_err
== 0 && memory_page
< (unsigned char *)CKSEG1
+ 0x1e00000;
48 memory_page
+= CHUNK_SIZE
) {
51 memcpy((void *)(CKSEG0
+ 0x80), &old_handler
, 0x80);
53 add_memory_region(0, (unsigned long)memory_page
- CKSEG1
- CHUNK_SIZE
,
58 * Use the REX prom calls to get hold of the memory bitmap, and thence
59 * determine memory size.
61 static inline void rex_setup_memory_region(void)
64 unsigned long mem_start
= 0, mem_size
= 0;
68 bm
= (memmap
*)CKSEG0ADDR(0x28000);
70 bitmap_size
= rex_getbitmap(bm
);
72 for (i
= 0; i
< bitmap_size
; i
++) {
73 /* FIXME: very simplistically only add full sets of pages */
74 if (bm
->bitmap
[i
] == 0xff)
75 mem_size
+= (8 * bm
->pagesize
);
77 mem_start
+= (8 * bm
->pagesize
);
79 add_memory_region(mem_start
, mem_size
, BOOT_MEM_RAM
);
80 mem_start
+= mem_size
+ (8 * bm
->pagesize
);
85 add_memory_region(mem_start
, mem_size
, BOOT_MEM_RAM
);
88 void __init
prom_meminit(u32 magic
)
90 if (!prom_is_rex(magic
))
91 pmax_setup_memory_region();
93 rex_setup_memory_region();
96 unsigned long __init
prom_free_prom_memory(void)
98 unsigned long addr
, end
;
101 * Free everything below the kernel itself but leave
102 * the first page reserved for the exception handlers.
105 #if defined(CONFIG_DECLANCE) || defined(CONFIG_DECLANCE_MODULE)
107 * Leave 128 KB reserved for Lance memory for
108 * IOASIC DECstations.
110 * XXX: save this address for use in dec_lance.c?
113 end
= __pa(&_text
) - 0x00020000;
120 ClearPageReserved(virt_to_page(__va(addr
)));
121 init_page_count(virt_to_page(__va(addr
)));
122 free_page((unsigned long)__va(addr
));
126 printk("Freeing unused PROM memory: %ldk freed\n",
127 (end
- PAGE_SIZE
) >> 10);
129 return end
- PAGE_SIZE
;