[RFC PATCH] edac: zynq: Added EDAC support for zynq ddr ecc controller

[Punnaiah Choudary Kalluri]

>-----Original Message-----
>From: Michal Simek [mailto:michal.simek at xilinx.com]
>Sent: Wednesday, March 12, 2014 10:20 PM
>To: Soren Brinkmann
>Cc: Michal Simek; monstr at monstr.eu; Mark Rutland; Punnaiah Choudary
>Kalluri; dougthompson at xmission.com; devicetree at vger.kernel.org; linux-
>doc at vger.kernel.org; linux-arm-kernel at lists.infradead.org; linux-
>kernel at vger.kernel.org; linux-edac at vger.kernel.org; robh+dt at kernel.org;
>Pawel Moll; ijc+devicetree at hellion.org.uk; galak at codeaurora.org;
>rob at landley.net; kpc528 at gmail.com; kalluripunnaiahchoudary at gmail.com;
>Punnaiah Choudary Kalluri
>Subject: Re: [RFC PATCH] edac: zynq: Added EDAC support for zynq ddr ecc
>controller
>
>On 03/12/2014 05:13 PM, Sören Brinkmann wrote:
>> On Wed, 2014-03-12 at 11:27AM +0100, Michal Simek wrote:
>>> On 03/11/2014 04:50 PM, Sören Brinkmann wrote:
>>>> On Tue, 2014-03-11 at 09:32AM +0100, Michal Simek wrote:
>>>>> On 03/10/2014 11:32 PM, Sören Brinkmann wrote:
>>>>>> On Mon, 2014-03-10 at 12:58PM +0100, Michal Simek wrote:
>>>>>>> On 03/10/2014 11:56 AM, Mark Rutland wrote:
>>>>>>>> On Sun, Mar 09, 2014 at 02:57:16AM +0000, Punnaiah Choudary
>Kalluri wrote:
>>>>>>>>> Added EDAC support for reporting the ecc errors of zynq ddr
>controller.
>>>>>>>>> The ddr ecc controller corrects single bit errors and detects double
>bit
>>>>>>>>> errors
>>>>>>>>>
>>>>>>>>> Signed-off-by: Punnaiah Choudary Kalluri <punnaia at xilinx.com>
>>>>>>>>> ---
>>>>>>>>>  .../devicetree/bindings/edac/zynq_edac.txt         |   18 +
>>>>>>>>>  drivers/edac/Kconfig                               |    7 +
>>>>>>>>>  drivers/edac/Makefile                              |    1 +
>>>>>>>>>  drivers/edac/zynq_edac.c                           |  613
>++++++++++++++++++++
>>>>>>>>>  4 files changed, 639 insertions(+), 0 deletions(-)
>>>>>>>>>  create mode 100644
>Documentation/devicetree/bindings/edac/zynq_edac.txt
>>>>>>>>>  create mode 100644 drivers/edac/zynq_edac.c
>>>>>>>>>
>>>>>>>>> diff --git
>a/Documentation/devicetree/bindings/edac/zynq_edac.txt
>b/Documentation/devicetree/bindings/edac/zynq_edac.txt
>>>>>>>>> new file mode 100644
>>>>>>>>> index 0000000..c21ff83
>>>>>>>>> --- /dev/null
>>>>>>>>> +++ b/Documentation/devicetree/bindings/edac/zynq_edac.txt
>>>>>>>>> @@ -0,0 +1,18 @@
>>>>>>>>> +Zynq EDAC driver, it does reports the DDR ECC single bit errors
>that are
>>>>>>>>> +corrected and double bit ecc errors that are detected by the DDR
>ECC controller.
>>>>>>>>> +ECC support for DDR is available in half-bus width(16 bit)
>configuration only.
>>>>>>>>> +
>>>>>>>>> +Required properties:
>>>>>>>>> +- compatible: Should be "xlnx,ps7-ddrc" or "xlnx,ps7-ddrc-1.00.a"
>>>>>>>>
>>>>>>>> Is this an or or a xor?
>>>>>>>
>>>>>>> Compatible string should be just xlnx,zynq-ddrc-1.00.a.
>>>>>>> Nothing with ps7.
>>>>>>
>>>>>> Isn't this vendor IP? IMHO, this should be something completely
>>>>>> different. Or if you want some Zynq-specific compat string it should
>>>>>> refer to an actual version string associated with Zynq. 1.00.a is not,
>>>>>> AFAIK.
>>>>>
>>>>> I have checked with Punnaiah that this is Synopsys DDR memory
>controller.
>>>>> Zynq is based on 1.4 version with some customization.
>>>>> It means I think reasonable solution is
>>>>> call it drivers/edac/synopsys_edac.c
>>>>> rename zynq_ in driver to synopsys_ and
>>>>> use xlnx,zynq-ddrc-1.00.a compatible string because zynq is not using
>>>>> clean synopsys version.
>>>>>
>>>>> I am not getting point why you don't like 1.00.a suffix here.
>>>>> Because of historical point of view compatible strings should be
>different
>>>>> for early silicon, silicon v1, silicon v2, silicon v3, etc
>>>>> but we haven't used it at all that's why we can use xilinx scheme
>>>>> which we are using for our soft IPs.
>>>>
>>>> Well, but you refer to Zynq which has silicon revisions you can use to
>>>> refer to a specific Zynq version. That matches data sheets. Zynq-1.00.a
>>>> is just completely made up and wouldn't be found in any data sheet.
>>>
>>> I didn't reply this one but we discussed this with Soren over phone.
>>> No problem to use Synopsys version A07 according TRM.
>>>
>>> Then compatible string is
>>> xlnx,zynq-ddrc-A07 and file name is synopsys_edac.c
>>
>> This seems to make sense. I'm never sure whether leading zeros are
>> actually needed and tend to remove them, but in general this looks like
>> a reasonable string to identify Zynq's DDR controller.
>
>A07 I found in Zynq TRM and probably has any conection to synopsys version
>scheme.
I have discussed with the design team and confirmed that the synopsis IP
version is 1.4 and looks like it is wrongly updated in TRM as A07.
So, I am going to use compatible string as xlnx,zynq-ddrc-1.4 and file name
as synopsys_edac.c and send you the updated patch soon.
Thanks for the review and suggestions

Regards,
Punnaiah
>
>Thanks,
>Michal
>
>
>



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