From: Rafał Miłecki Date: Sat, 19 Apr 2014 10:49:46 +0000 (+0200) Subject: MIPS: BCM47XX: Slightly clean memory detection X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=96a8123e5f965825a61a74617b8da1199646d392;p=openwrt%2Fstaging%2Fblogic.git MIPS: BCM47XX: Slightly clean memory detection Patch was tested on devices with 64 MiB and 256 MiB of RAM. It documents every part nicely and drops this hacky part of code: max = off | ((128 << 20) - 1); Signed-off-by: Rafał Miłecki Cc: linux-mips@linux-mips.org Cc: Hauke Mehrtens Patchwork: https://patchwork.linux-mips.org/patch/6808/ Signed-off-by: Ralf Baechle --- diff --git a/arch/mips/bcm47xx/prom.c b/arch/mips/bcm47xx/prom.c index 0af808dfd1ca..1a03a2f43496 100644 --- a/arch/mips/bcm47xx/prom.c +++ b/arch/mips/bcm47xx/prom.c @@ -69,15 +69,18 @@ static __init void prom_init_mem(void) * BCM47XX uses 128MB for addressing the ram, if the system contains * less that that amount of ram it remaps the ram more often into the * available space. - * Accessing memory after 128MB will cause an exception. - * max contains the biggest possible address supported by the platform. - * If the method wants to try something above we assume 128MB ram. */ - off = (unsigned long)prom_init; - max = off | ((128 << 20) - 1); - for (mem = (1 << 20); mem < (128 << 20); mem += (1 << 20)) { - if ((off + mem) > max) { - mem = (128 << 20); + + /* Physical address, without mapping to any kernel segment */ + off = CPHYSADDR((unsigned long)prom_init); + + /* Accessing memory after 128 MiB will cause an exception */ + max = 128 << 20; + + for (mem = 1 << 20; mem < max; mem += 1 << 20) { + /* Loop condition may be not enough, off may be over 1 MiB */ + if (off + mem >= max) { + mem = max; printk(KERN_DEBUG "assume 128MB RAM\n"); break; }