xref: /openbmc/linux/arch/mips/ar7/memory.c (revision 63dc02bd)
1 /*
2  * Copyright (C) 2007 Felix Fietkau <nbd@openwrt.org>
3  * Copyright (C) 2007 Eugene Konev <ejka@openwrt.org>
4  *
5  * This program is free software; you can redistribute it and/or modify
6  * it under the terms of the GNU General Public License as published by
7  * the Free Software Foundation; either version 2 of the License, or
8  * (at your option) any later version.
9  *
10  * This program is distributed in the hope that it will be useful,
11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13  * GNU General Public License for more details.
14  *
15  * You should have received a copy of the GNU General Public License
16  * along with this program; if not, write to the Free Software
17  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
18  */
19 #include <linux/bootmem.h>
20 #include <linux/init.h>
21 #include <linux/mm.h>
22 #include <linux/module.h>
23 #include <linux/pfn.h>
24 #include <linux/proc_fs.h>
25 #include <linux/string.h>
26 #include <linux/swap.h>
27 
28 #include <asm/bootinfo.h>
29 #include <asm/page.h>
30 #include <asm/sections.h>
31 
32 #include <asm/mach-ar7/ar7.h>
33 #include <asm/mips-boards/prom.h>
34 
35 static int __init memsize(void)
36 {
37 	u32 size = (64 << 20);
38 	u32 *addr = (u32 *)KSEG1ADDR(AR7_SDRAM_BASE + size - 4);
39 	u32 *kernel_end = (u32 *)KSEG1ADDR(CPHYSADDR((u32)&_end));
40 	u32 *tmpaddr = addr;
41 
42 	while (tmpaddr > kernel_end) {
43 		*tmpaddr = (u32)tmpaddr;
44 		size >>= 1;
45 		tmpaddr -= size >> 2;
46 	}
47 
48 	do {
49 		tmpaddr += size >> 2;
50 		if (*tmpaddr != (u32)tmpaddr)
51 			break;
52 		size <<= 1;
53 	} while (size < (64 << 20));
54 
55 	writel((u32)tmpaddr, &addr);
56 
57 	return size;
58 }
59 
60 void __init prom_meminit(void)
61 {
62 	unsigned long pages;
63 
64 	pages = memsize() >> PAGE_SHIFT;
65 	add_memory_region(PHYS_OFFSET, pages << PAGE_SHIFT, BOOT_MEM_RAM);
66 }
67 
68 void __init prom_free_prom_memory(void)
69 {
70 	/* Nothing to free */
71 }
72