Subject: Re: PPC4xx ECC Configs, Defines and Source

From: Grant Erickson <[email-masked]>
Date: Mon, 08 Dec 2008 22:32:12 -0800

On 12/8/08 9:57 PM, Stefan Roese wrote:
> On Tuesday 09 December 2008, Grant Erickson wrote:
>>> Just to make sure, are you planning on just implementing a driver to
>>> deal with whatever settings the bootloader configured?  E.g., if ECC is
>>> enabled deal with correctable/uncorrectable errors and if not, do
>>> nothing?  Basically you are looking to implement a scrub driver, yes?
>>> 
>>> I ask because since ECC is memory module specific and memory controller
>>> setup is pretty tricky, I think it's best to leave whatever
>>> configuration the bootloader set and work with that.  Having to redo
>>> memory controller setups in Linux to enable ECC isn't something I'd
>>> look forward to.
>> 
>> Precisely. The driver will basically check if ECC is enabled (as was
>> set/not set by u-boot) and, if so, will take ECC SEC/DED interrupts, log
>> SEC errors to some data structure fetchable by a proc entry or some device
>> node. For DED errors, execute on some policy, at its simplest, generating a
>> panic.
>> 
>> At no point will the driver/code attempt to change the controller
>> configuration beyond reading/clearing ECC event/interrupt status.
> 
> Seems that such a driver should be implemented in the Linux EDAC subsystem
> (see drivers/edac and Documentation/edac.txt) to me. Did you take a look at
> this?

Stefan:

Thanks for the reference. I will give this a closer examination. At first
glance, this looks promising. Somehow, this managed to escape my Google
search dragnet. Their project team may need to work on their page keywords.

Thanks again,

Grant