From: Mikhail Zolotaryov <lebon@lebon.org.ua>
To: linux-kernel@vger.kernel.org
Cc: linuxppc-dev@ozlabs.org, jwboyer@linux.vnet.ibm.com
Subject: [PATCH] powerpc 4xx: DDR0_14[REDUC] decoded incorrectly
Date: Mon, 09 Mar 2009 18:21:36 +0200 [thread overview]
Message-ID: <49B54210.5040709@lebon.org.ua> (raw)
[-- Attachment #1: Type: text/plain, Size: 434 bytes --]
Hi,
according to the PPC440EPx Embedded Processor User Manual (rev 1.14)
DDR0_14[REDUC] bit has the following meaning:
REDUC - Enable the half data path feature of the controller
0 = Standard operation using full 64/72-bit memory bus
1 = Memory data path width is 32/40 bits
However, "1" is decoded as 64 bit (8 byte), "0" - as 32 bit (4 byte) bus
by the kernel code. My understanding is this is not correct - patch
attached.
[-- Attachment #2: patch-ibm4xx_denali_fixup_memsize.patch --]
[-- Type: text/plain, Size: 412 bytes --]
--- linux.orig/arch/powerpc/boot/4xx.c 2009-03-09 17:55:01.000000000 +0200
+++ linux/arch/powerpc/boot/4xx.c 2009-03-09 17:58:07.000000000 +0200
@@ -193,9 +193,9 @@
val = SDRAM0_READ(DDR0_14);
if (DDR_GET_VAL(val, DDR_REDUC, DDR_REDUC_SHIFT))
- dpath = 8; /* 64 bits */
- else
dpath = 4; /* 32 bits */
+ else
+ dpath = 8; /* 64 bits */
/* get address pins (rows) */
val = SDRAM0_READ(DDR0_42);
next reply other threads:[~2009-03-09 16:36 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-03-09 16:21 Mikhail Zolotaryov [this message]
2009-03-09 17:12 ` [PATCH] powerpc 4xx: DDR0_14[REDUC] decoded incorrectly Josh Boyer
2009-03-09 21:17 ` Mikhail Zolotaryov
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