From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from alln-iport-1.cisco.com (alln-iport-1.cisco.com [173.37.142.88]) (using TLSv1.2 with cipher DHE-RSA-SEED-SHA (128/128 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3rpBSZ5Km3zDqpR for ; Tue, 12 Jul 2016 03:10:54 +1000 (AEST) Subject: Re: t1040 IFC flash driver Extended Chip Select To: Scott Wood , Raghav Dogra , Brian Norris , Jaiprakash Singh , Scott Wood , Lijun Pan , "linuxppc-dev@lists.ozlabs.org" , "xe-kernel@external.cisco.com" References: <577D68B8.8020305@cisco.com> <577E79D4.1010709@cisco.com> <577EB10B.7010601@cisco.com> <577EC0FC.8020304@cisco.com> <577ECE6C.3000100@cisco.com> <577ED12C.30105@cisco.com> <577EEA56.3070300@cisco.com> <5783CB03.4030806@cisco.com> From: Daniel Walker Message-ID: <5783D31A.3090609@cisco.com> Date: Mon, 11 Jul 2016 10:10:50 -0700 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=windows-1252; format=flowed List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On 07/11/2016 09:55 AM, Scott Wood wrote: > On 07/11/2016 11:36 AM, Daniel Walker wrote: >> On 07/08/2016 06:12 PM, Scott Wood wrote: >>> On 07/07/2016 06:48 PM, Daniel Walker wrote: >>>> On 07/07/2016 03:37 PM, Scott Wood wrote: >>>>> On 07/07/2016 05:01 PM, Daniel Walker wrote: >>>>>> On 07/07/2016 02:59 PM, Scott Wood wrote: >>>>>>> On 07/07/2016 04:49 PM, Daniel Walker wrote: >>>>>>>> On 07/07/2016 02:23 PM, Scott Wood wrote: >>>>>>>>> I suspect that add the usage of cspr_ext into the driver would fix the >>>>>>>>> issue we have. It reads like you would find that acceptable ? >>>>>>>>> What specifically is the problem you're having? Is it that CSPR_EXT is >>>>>>>>> not getting written to, and thus the device does not appear at the >>>>>>>>> address that it should? >>>>>>>>> >>>>>>>>> Or is the driver matching incorrectly? The only way the driver's lack >>>>>>>>> of using CSPR_EXT to match would be a problem would be if you have >>>>>>>>> multiple chipselects with the same address in the lower 32 bits, and >>>>>>>>> only CSPR_EXT distinguishing them. Since you proposed a device tree >>>>>>>>> binding that assumes all devices have the same CSPR_EXT, I doubt that's >>>>>>>>> the case, so I doubt adding CSPR_EXT matching to the driver will solve >>>>>>>>> your problem. >>>>>>>>> >>>>>>>>> -Scott >>>>>>>>> >>>>>>>> I didn't do the debug on this. From my perspective it's either flash >>>>>>>> works, or it doesn't work. We need the code below for it to work, >>>>>>> Adding CSPR_EXT matching to the driver will not accomplish the same >>>>>>> thing as that code. >>>>>>> >>>>>> So from u-boot perspective, the values in the device tree under "ranges" >>>>>> or parts of it, are place into the cspr and cspr_ext ? Is that how it's >>>>>> suppose to work ? >>>>> U-Boot writes values that are hardcoded in the board config header. >>>>> These values (as well as the area covered by the IFC LAW) need to match >>>>> the address in the device tree, but U-Boot doesn't get them from the >>>>> device tree. >>>>> >>>> I was suggesting the values it writes are the same as the ones inside >>>> the device tree. So we could have both csrp and csrp_ext written from >>>> the driver and the values would >>>> come from the ranges property. >>> There's more to CSPR than just the address. The driver should either be >>> able to assume that all of CSPR/CSOR has been correctly initialized, or >>> it should assume none of that has been initialized -- which again, >>> requires the attribute information to be in the device tree. If you're >>> doing something in between, then that's a board quirk rather than a >>> general solution. >>> >>> -Scott >>> >> It would seems like a good idea to add it then. I think it can be piece >> mail, rather than all or nothing tho. How difficult is adding the other >> part to the driver , v.s. just the cspr_ext ? > Writing only cspr_ext is a hack to work around a bug and should not be > disguised as a "piecemeal" implementation of something different. > > -Scott Ok .. How hard is it to do all the stuff your asking for ? Daniel