From c47cc20ca53e792938556aa29103fa889ce0d858 Mon Sep 17 00:00:00 2001 From: Hauke Mehrtens Date: Wed, 3 Oct 2012 11:34:17 +0000 Subject: [PATCH] MIPS: BCM47XX: improve memory size detection 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 it is better to check for a bigger part of the memory to decrease the chance of wrong results. This should fix a problem we saw in OpenWrt, where the detected available memory decreed on some devices when doing a soft reboot. Signed-off-by: Hauke Mehrtens Patchwork: http://patchwork.linux-mips.org/patch/4362 Signed-off-by: John Crispin --- arch/mips/bcm47xx/prom.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/arch/mips/bcm47xx/prom.c b/arch/mips/bcm47xx/prom.c index 22258a4c652b..8c155afb1299 100644 --- a/arch/mips/bcm47xx/prom.c +++ b/arch/mips/bcm47xx/prom.c @@ -1,6 +1,7 @@ /* * Copyright (C) 2004 Florian Schirmer * Copyright (C) 2007 Aurelien Jarno + * Copyright (C) 2010-2012 Hauke Mehrtens * * 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; struct cpuinfo_mips *c = ¤t_cpu_data; /* Figure out memory size by finding aliases. @@ -145,15 +147,15 @@ 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; + 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 (!memcmp(prom_init, prom_init + mem, 32)) break; } -- 2.34.1