From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755264AbbBTRhS (ORCPT ); Fri, 20 Feb 2015 12:37:18 -0500 Received: from mail-wi0-f172.google.com ([209.85.212.172]:65487 "EHLO mail-wi0-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754615AbbBTRhQ convert rfc822-to-8bit (ORCPT ); Fri, 20 Feb 2015 12:37:16 -0500 Subject: Re: [PATCH 2/4] of: DT quirks infrastructure Mime-Version: 1.0 (Mac OS X Mail 8.2 \(2070.6\)) Content-Type: text/plain; charset=utf-8 From: Pantelis Antoniou In-Reply-To: Date: Fri, 20 Feb 2015 19:37:08 +0200 Cc: Peter Hurley , Frank Rowand , Mark Rutland , "devicetree@vger.kernel.org" , Tony Lindgren , Koen Kooi , Nicolas Ferre , "linux-kernel@vger.kernel.org" , Grant Likely , "linux-arm-kernel@lists.infradead.org" , Matt Porter , Guenter Roeck , Ludovic Desroches Content-Transfer-Encoding: 8BIT Message-Id: <37628878-C4B4-49F6-9000-B993250F54AB@konsulko.com> References: <1424271576-1952-3-git-send-email-pantelis.antoniou@konsulko.com> <20150218154106.GC29429@leverpostej> <20150218173115.GG29429@leverpostej> <76BD1B22-BAED-4205-9B34-186907CE0217@konsulko.com> <54E613E7.2020405@gmail.com> <670D0881-DBF0-45E8-A502-A6DB2B77A750@konsulko.com> <54E61DD2.3060002@gmail.com> <53F2F94C-0C43-4A54-B8CD-EEC454A0AC19@konsulko.com> <54E742F2.80506@hurleysoftware.com> <20150220143533.GA29908@odux.rfo.atmel.com> To: Rob Herring X-Mailer: Apple Mail (2.2070.6) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Rob, > On Feb 20, 2015, at 19:30 , Rob Herring wrote: > > On Fri, Feb 20, 2015 at 8:35 AM, Ludovic Desroches > wrote: >> On Fri, Feb 20, 2015 at 09:21:38AM -0500, Peter Hurley wrote: >>> On 02/19/2015 12:38 PM, Pantelis Antoniou wrote: >>>> >>>>> On Feb 19, 2015, at 19:30 , Frank Rowand wrote: >>>>> >>>>> On 2/19/2015 9:00 AM, Pantelis Antoniou wrote: >>>>>> Hi Frank, > > [...] > >>>>>> This is one of those things that the kernel community doesn’t understand which makes people >>>>>> who push product quite mad. >>>>>> >>>>>> Engineering a product is not only about meeting customer spec, in order to turn a profit >>>>>> the whole endeavor must be engineered as well for manufacturability. >>>>>> >>>>>> Yes, you can always manually install files in the bootloader. For 1 board no problem. >>>>>> For 10 doable. For 100 I guess you can hire an extra guy. For 1 million? Guess what, >>>>>> instead of turning a profit you’re losing money if you only have a few cents of profit >>>>>> per unit. >>>>> >>>>> I'm not installing physical components manually. Why would I be installing software >>>>> manually? (rhetorical question) >>>>> >>>> >>>> Because on high volume product runs the flash comes preprogrammed and is soldered as is. >>>> >>>> Having a single binary to flash to every revision of the board makes logistics considerably >>>> easier. >>>> >>>> Having to boot and tweak the bootloader settings to select the correct dtb (even if it’s present >>>> on the flash medium) takes time and is error-prone. >>>> >>>> Factory time == money, errors == money. >>>> >>>>>> >>>>>> No knobs to tweak means no knobs to break. And a broken knob can have pretty bad consequences >>>>>> for a few million units. >>>>> >>>>> And you produce a few million units before testing that the first one off the line works? >>>>> >>>> >>>> The first one off the line works. The rest will get some burn in and functional testing if you’re >>>> lucky. In many cases where the product is very cheap it might make financial sense to just ship >>>> as is and deal with recalls, if you’re reasonably happy after a little bit of statistical sampling. >>>> >>>> Hardware is hard :) >>> >>> I'm failing to see how this series improves your manufacturing process at all. >>> >>> 1. Won't you have to provide the factory with different eeprom images for the >>> White and Black? You _trust_ them to get that right, or more likely, you >>> have process control procedures in place so that you don't get 1 million Blacks >>> flashed with the White eeprom image. >>> >>> 2. The White and Black use different memory technology so it's not as if the >>> eMMC from the Black will end up on the White SMT line (or vice versa). >>> >>> 3 For that matter, why wouldn't you worry that all the microSD cards intended >>> for the White were accidentally assembled with the first 50,000 Blacks; at >>> that point you're losing a lot more than a few cents of profit. And that has >>> nothing to do with what image you provided. >>> >> >> As you said, we can imagine many reasons to have a failure during the >> production, having several DTB files will increase the risk. > > Then package them as a single file. You can even use DT to do that. > See u-boot FIT image. > In the ideal case there is no u-boot, and no bootloader. Packaging 27 difference DTBs, as in the Atmel people case, differing in only a few properties seems a waste of space, no? We keep on dancing around the issue, namely that DT does not have a quirk/variant mechanism. I feel that it is a glaring omission. We can’t keep shoveling crap over the fence to firmware and expect it to get buried there. > Rob Regards — Pantelis From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pantelis Antoniou Subject: Re: [PATCH 2/4] of: DT quirks infrastructure Date: Fri, 20 Feb 2015 19:37:08 +0200 Message-ID: <37628878-C4B4-49F6-9000-B993250F54AB@konsulko.com> References: <1424271576-1952-3-git-send-email-pantelis.antoniou@konsulko.com> <20150218154106.GC29429@leverpostej> <20150218173115.GG29429@leverpostej> <76BD1B22-BAED-4205-9B34-186907CE0217@konsulko.com> <54E613E7.2020405@gmail.com> <670D0881-DBF0-45E8-A502-A6DB2B77A750@konsulko.com> <54E61DD2.3060002@gmail.com> <53F2F94C-0C43-4A54-B8CD-EEC454A0AC19@konsulko.com> <54E742F2.80506@hurleysoftware.com> <20150220143533.GA29908@odux.rfo.atmel.com> Mime-Version: 1.0 (Mac OS X Mail 8.2 \(2070.6\)) Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: Rob Herring Cc: Peter Hurley , Frank Rowand , Mark Rutland , "devicetree@vger.kernel.org" , Tony Lindgren , Koen Kooi , Nicolas Ferre , "linux-kernel@vger.kernel.org" , Grant Likely , "linux-arm-kernel@lists.infradead.org" , Matt Porter , Guenter Roeck , Ludovic Desroches List-Id: devicetree@vger.kernel.org Hi Rob, > On Feb 20, 2015, at 19:30 , Rob Herring wrote= : >=20 > On Fri, Feb 20, 2015 at 8:35 AM, Ludovic Desroches > wrote: >> On Fri, Feb 20, 2015 at 09:21:38AM -0500, Peter Hurley wrote: >>> On 02/19/2015 12:38 PM, Pantelis Antoniou wrote: >>>>=20 >>>>> On Feb 19, 2015, at 19:30 , Frank Rowand = wrote: >>>>>=20 >>>>> On 2/19/2015 9:00 AM, Pantelis Antoniou wrote: >>>>>> Hi Frank, >=20 > [...] >=20 >>>>>> This is one of those things that the kernel community doesn=E2=80= =99t understand which makes people >>>>>> who push product quite mad. >>>>>>=20 >>>>>> Engineering a product is not only about meeting customer spec, i= n order to turn a profit >>>>>> the whole endeavor must be engineered as well for manufacturabil= ity. >>>>>>=20 >>>>>> Yes, you can always manually install files in the bootloader. Fo= r 1 board no problem. >>>>>> For 10 doable. For 100 I guess you can hire an extra guy. For 1 = million? Guess what, >>>>>> instead of turning a profit you=E2=80=99re losing money if you o= nly have a few cents of profit >>>>>> per unit. >>>>>=20 >>>>> I'm not installing physical components manually. Why would I be = installing software >>>>> manually? (rhetorical question) >>>>>=20 >>>>=20 >>>> Because on high volume product runs the flash comes preprogrammed = and is soldered as is. >>>>=20 >>>> Having a single binary to flash to every revision of the board mak= es logistics considerably >>>> easier. >>>>=20 >>>> Having to boot and tweak the bootloader settings to select the cor= rect dtb (even if it=E2=80=99s present >>>> on the flash medium) takes time and is error-prone. >>>>=20 >>>> Factory time =3D=3D money, errors =3D=3D money. >>>>=20 >>>>>>=20 >>>>>> No knobs to tweak means no knobs to break. And a broken knob can= have pretty bad consequences >>>>>> for a few million units. >>>>>=20 >>>>> And you produce a few million units before testing that the first= one off the line works? >>>>>=20 >>>>=20 >>>> The first one off the line works. The rest will get some burn in a= nd functional testing if you=E2=80=99re >>>> lucky. In many cases where the product is very cheap it might make= financial sense to just ship >>>> as is and deal with recalls, if you=E2=80=99re reasonably happy af= ter a little bit of statistical sampling. >>>>=20 >>>> Hardware is hard :) >>>=20 >>> I'm failing to see how this series improves your manufacturing proc= ess at all. >>>=20 >>> 1. Won't you have to provide the factory with different eeprom imag= es for the >>> White and Black? You _trust_ them to get that right, or more lik= ely, you >>> have process control procedures in place so that you don't get 1 = million Blacks >>> flashed with the White eeprom image. >>>=20 >>> 2. The White and Black use different memory technology so it's not = as if the >>> eMMC from the Black will end up on the White SMT line (or vice ve= rsa). >>>=20 >>> 3 For that matter, why wouldn't you worry that all the microSD car= ds intended >>> for the White were accidentally assembled with the first 50,000 B= lacks; at >>> that point you're losing a lot more than a few cents of profit. A= nd that has >>> nothing to do with what image you provided. >>>=20 >>=20 >> As you said, we can imagine many reasons to have a failure during th= e >> production, having several DTB files will increase the risk. >=20 > Then package them as a single file. You can even use DT to do that. > See u-boot FIT image. >=20 In the ideal case there is no u-boot, and no bootloader. Packaging 27 difference DTBs, as in the Atmel people case, differing in= only a few=20 properties seems a waste of space, no? =20 We keep on dancing around the issue, namely that DT does not have a qui= rk/variant mechanism. I feel that it is a glaring omission. We can=E2=80=99t keep = shoveling crap over the fence to firmware and expect it to get buried there. > Rob Regards =E2=80=94 Pantelis From mboxrd@z Thu Jan 1 00:00:00 1970 From: pantelis.antoniou@konsulko.com (Pantelis Antoniou) Date: Fri, 20 Feb 2015 19:37:08 +0200 Subject: [PATCH 2/4] of: DT quirks infrastructure In-Reply-To: References: <1424271576-1952-3-git-send-email-pantelis.antoniou@konsulko.com> <20150218154106.GC29429@leverpostej> <20150218173115.GG29429@leverpostej> <76BD1B22-BAED-4205-9B34-186907CE0217@konsulko.com> <54E613E7.2020405@gmail.com> <670D0881-DBF0-45E8-A502-A6DB2B77A750@konsulko.com> <54E61DD2.3060002@gmail.com> <53F2F94C-0C43-4A54-B8CD-EEC454A0AC19@konsulko.com> <54E742F2.80506@hurleysoftware.com> <20150220143533.GA29908@odux.rfo.atmel.com> Message-ID: <37628878-C4B4-49F6-9000-B993250F54AB@konsulko.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi Rob, > On Feb 20, 2015, at 19:30 , Rob Herring wrote: > > On Fri, Feb 20, 2015 at 8:35 AM, Ludovic Desroches > wrote: >> On Fri, Feb 20, 2015 at 09:21:38AM -0500, Peter Hurley wrote: >>> On 02/19/2015 12:38 PM, Pantelis Antoniou wrote: >>>> >>>>> On Feb 19, 2015, at 19:30 , Frank Rowand wrote: >>>>> >>>>> On 2/19/2015 9:00 AM, Pantelis Antoniou wrote: >>>>>> Hi Frank, > > [...] > >>>>>> This is one of those things that the kernel community doesn?t understand which makes people >>>>>> who push product quite mad. >>>>>> >>>>>> Engineering a product is not only about meeting customer spec, in order to turn a profit >>>>>> the whole endeavor must be engineered as well for manufacturability. >>>>>> >>>>>> Yes, you can always manually install files in the bootloader. For 1 board no problem. >>>>>> For 10 doable. For 100 I guess you can hire an extra guy. For 1 million? Guess what, >>>>>> instead of turning a profit you?re losing money if you only have a few cents of profit >>>>>> per unit. >>>>> >>>>> I'm not installing physical components manually. Why would I be installing software >>>>> manually? (rhetorical question) >>>>> >>>> >>>> Because on high volume product runs the flash comes preprogrammed and is soldered as is. >>>> >>>> Having a single binary to flash to every revision of the board makes logistics considerably >>>> easier. >>>> >>>> Having to boot and tweak the bootloader settings to select the correct dtb (even if it?s present >>>> on the flash medium) takes time and is error-prone. >>>> >>>> Factory time == money, errors == money. >>>> >>>>>> >>>>>> No knobs to tweak means no knobs to break. And a broken knob can have pretty bad consequences >>>>>> for a few million units. >>>>> >>>>> And you produce a few million units before testing that the first one off the line works? >>>>> >>>> >>>> The first one off the line works. The rest will get some burn in and functional testing if you?re >>>> lucky. In many cases where the product is very cheap it might make financial sense to just ship >>>> as is and deal with recalls, if you?re reasonably happy after a little bit of statistical sampling. >>>> >>>> Hardware is hard :) >>> >>> I'm failing to see how this series improves your manufacturing process at all. >>> >>> 1. Won't you have to provide the factory with different eeprom images for the >>> White and Black? You _trust_ them to get that right, or more likely, you >>> have process control procedures in place so that you don't get 1 million Blacks >>> flashed with the White eeprom image. >>> >>> 2. The White and Black use different memory technology so it's not as if the >>> eMMC from the Black will end up on the White SMT line (or vice versa). >>> >>> 3 For that matter, why wouldn't you worry that all the microSD cards intended >>> for the White were accidentally assembled with the first 50,000 Blacks; at >>> that point you're losing a lot more than a few cents of profit. And that has >>> nothing to do with what image you provided. >>> >> >> As you said, we can imagine many reasons to have a failure during the >> production, having several DTB files will increase the risk. > > Then package them as a single file. You can even use DT to do that. > See u-boot FIT image. > In the ideal case there is no u-boot, and no bootloader. Packaging 27 difference DTBs, as in the Atmel people case, differing in only a few properties seems a waste of space, no? We keep on dancing around the issue, namely that DT does not have a quirk/variant mechanism. I feel that it is a glaring omission. We can?t keep shoveling crap over the fence to firmware and expect it to get buried there. > Rob Regards ? Pantelis