diff options
author | Rafał Miłecki <zajec5@gmail.com> | 2014-04-19 10:49:46 (GMT) |
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committer | Ralf Baechle <ralf@linux-mips.org> | 2014-05-30 09:00:21 (GMT) |
commit | 96a8123e5f965825a61a74617b8da1199646d392 (patch) | |
tree | 5c4c5a54046601668f23627c733883bd05c60a08 /arch/mips/bcm47xx/prom.c | |
parent | d8ce75934b888df0bd73dfd9c030a2b034a04977 (diff) | |
download | linux-96a8123e5f965825a61a74617b8da1199646d392.tar.xz |
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 <zajec5@gmail.com>
Cc: linux-mips@linux-mips.org
Cc: Hauke Mehrtens <hauke@hauke-m.de>
Patchwork: https://patchwork.linux-mips.org/patch/6808/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Diffstat (limited to 'arch/mips/bcm47xx/prom.c')
-rw-r--r-- | arch/mips/bcm47xx/prom.c | 19 |
1 files changed, 11 insertions, 8 deletions
diff --git a/arch/mips/bcm47xx/prom.c b/arch/mips/bcm47xx/prom.c index 0af808d..1a03a2f 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; } |