From: Stefan Nickl <Stefan.Nickl@kontron.com>
To: Kumar Gala <kumar.gala@freescale.com>, Andrew Morton <akpm@osdl.org>
Cc: linuxppc-embedded <linuxppc-embedded@ozlabs.org>
Subject: [PATCH] MPC8555 CPM2 size/pointers for FCCs aka "All-ones problem"
Date: Wed, 30 Mar 2005 09:44:24 +0200 [thread overview]
Message-ID: <1112168665.12794.24.camel@lucy.pep-kaufbeuren.de> (raw)
[-- Attachment #1: Type: text/plain, Size: 784 bytes --]
I've seen that MPC8555 support also made it into linux-2.6 by now.
I don't have hardware and time to test, but it looks like this bug has
made it over from the linuxppc-2.4 tree. The 8541/8555 has a smaller CPM
DPRAM than the standard CPM2, just like the 8272.
Unfortunately, the manual recommends you to use a segment of CPM DPRAM
that is not implemented in the 8541/55. If the smaller DPRAM is not
taken into account, fcc_enet.c will initialise the internal CPM buffer
pointers (fcc_riptr/fcc_tiptr) to invalid offsets, with the result that
all the FCC will ever send and receive are 0xff-en.
See also "All-ones problem with FCC1 on MPC8541" ~October 2004 on
linuxppc-embedded.
Signed-off-by: Stefan Nickl <Stefan.Nickl@kontron.com>
--
Stefan Nickl
Kontron Modular Computers
[-- Attachment #2: cpm2_8555.patch --]
[-- Type: text/x-patch, Size: 451 bytes --]
--- linux-2.5/include/asm-ppc/cpm2.h.old 2005-03-30 08:49:54.000000000 +0200
+++ linux-2.5/include/asm-ppc/cpm2.h 2005-03-30 08:56:07.000000000 +0200
@@ -86,7 +86,7 @@
*/
#define CPM_DATAONLY_BASE ((uint)128)
#define CPM_DP_NOSPACE ((uint)0x7fffffff)
-#ifdef CONFIG_8272
+#if defined(CONFIG_8272) || defined(CONFIG_MPC8555)
#define CPM_DATAONLY_SIZE ((uint)(8 * 1024) - CPM_DATAONLY_BASE)
#define CPM_FCC_SPECIAL_BASE ((uint)0x00009000)
#else
reply other threads:[~2005-03-30 7:44 UTC|newest]
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