[PATCH] MPC8555 CPM2 size/pointers for FCCs aka "All-ones problem"

[Stefan Nickl]

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 at kontron.com>

-- 
Stefan Nickl
Kontron Modular Computers

-------------- next part --------------
A non-text attachment was scrubbed...
Name: cpm2_8555.patch
Type: text/x-patch
Size: 451 bytes
Desc: not available
Url : http://ozlabs.org/pipermail/linuxppc-embedded/attachments/20050330/2c87af63/attachment.bin