On 29/09/12 20:12, Hauke Mehrtens wrote:
The memory size is detected by finding a place where it repeats in
memory. Currently we are just checking when the function prom_init is
seen again, but with this patch it also checks some more bytes.
This should fix a problem we saw in OpenWrt, where the detected
available memory decreased on some devices when doing a soft reboot.
Signed-off-by: Hauke Mehrtens<hauke@xxxxxxxxxx>
---
arch/mips/bcm47xx/prom.c | 14 ++++++++++----
1 file changed, 10 insertions(+), 4 deletions(-)
diff --git a/arch/mips/bcm47xx/prom.c b/arch/mips/bcm47xx/prom.c
index 22258a4..c18f59a 100644
--- a/arch/mips/bcm47xx/prom.c
+++ b/arch/mips/bcm47xx/prom.c
@@ -1,6 +1,7 @@
/*
* Copyright (C) 2004 Florian Schirmer<jolt@xxxxxxxxxx>
* Copyright (C) 2007 Aurelien Jarno<aurelien@xxxxxxxxxxx>
+ * Copyright (C) 2010-2012 Hauke Mehrtens<hauke@xxxxxxxxxx>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
@@ -128,6 +129,7 @@ static __init void prom_init_mem(void)
{
unsigned long mem;
unsigned long max;
+ unsigned long off, data, off1, data1;
struct cpuinfo_mips *c =¤t_cpu_data;
/* Figure out memory size by finding aliases.
@@ -145,15 +147,19 @@ static __init void prom_init_mem(void)
* max contains the biggest possible address supported by the platform.
* If the method wants to try something above we assume 128MB ram.
*/
- max = ((unsigned long)(prom_init) | ((128<< 20) - 1));
+ off = (unsigned long)prom_init;
+ data = *(unsigned long *)prom_init;
+ off1 = off + 4;
+ data1 = *(unsigned long *)off1;
+ max = off | ((128<< 20) - 1);
for (mem = (1<< 20); mem< (128<< 20); mem += (1<< 20)) {
- if (((unsigned long)(prom_init) + mem)> max) {
+ if ((off + mem)> max) {
mem = (128<< 20);
printk(KERN_DEBUG "assume 128MB RAM\n");
break;
}
- if (*(unsigned long *)((unsigned long)(prom_init) + mem) ==
- *(unsigned long *)(prom_init))
+ if ((*(unsigned long *)(off + mem) == data)&&
+ (*(unsigned long *)(off1 + mem) == data1))
break;
}
Hi Hauke,
somehow i have the feeling, that using memcmp() should be used here
instead of comparing memory by hand.
John
