On Apr 29, 2009, at 2:37 AM, Andrew Morton wrote:
Let's cc the suitable people.
On Tue, 28 Apr 2009 18:23:42 -0700 "Jeff Haran" <jha...@brocade.com>
wrote:
Hi,
Recent versions of this function contain the following snippets:
if (err_detect & DDR_EDE_SBE)
edac_mc_handle_ce(mci, pfn, err_addr & PAGE_MASK,
syndrome, row_index, 0, mci->ctl_name);
if (err_detect & DDR_EDE_MBE)
edac_mc_handle_ue(mci, pfn, err_addr & PAGE_MASK,
row_index, mci->ctl_name);
I am pretty sure the references to PAGE_MASK should be proceeded by a
tilda, as in:
if (err_detect & DDR_EDE_SBE)
edac_mc_handle_ce(mci, pfn, err_addr & ~PAGE_MASK,
syndrome, row_index, 0, mci->ctl_name);
if (err_detect & DDR_EDE_MBE)
edac_mc_handle_ue(mci, pfn, err_addr & ~PAGE_MASK,
row_index, mci->ctl_name);
Could well be. PAGE_MASK is very easy to get wrong. I've _never_
trusted my own memory of it and I always have to go back to the
definition when reviewing code :(
This should ~PAGE_MASK to get the offset into the page.
Much as I would like to submit a tested patch like the rest of the
world, I find myself in the situation where the only Freescale target
system I have to test on is running a 3 year old kernel (2.6.14),
which
preceeds the introduction of EDAC driver support, at least for
Freescale. So the best I can do is borrow from the new EDAC driver
and
backport it to the old kernel.
But I have learned a few things in this process and can thus share
what
I've learned as it may be of help to the EDAC driver developers:
1) Before you read the Freescale 8548 CAPTURE_ADDRESS register, you
want
to read CAPTURE_ATTRIBUTES first and make sure the VLD bit (least
significant bit in the register) is set or else the data in
CAPTURE_ADDRESS may not be yet valid.
2) When you are done scrubbing the memory with the single bit
error, you
want to write 0 to CAPTURE_ATTRIBUTES so as to clear VLD and thus
setup
the ECC capture logic to capture the next single bit error.
This is a correct description based on how FSL error HW works.
- k
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