From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by yocto-www.yoctoproject.org (Postfix, from userid 118) id 35435E0076C; Fri, 7 Nov 2014 08:39:55 -0800 (PST) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on yocto-www.yoctoproject.org X-Spam-Level: X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00 autolearn=ham version=3.3.1 X-Spam-HAM-Report: * -1.9 BAYES_00 BODY: Bayes spam probability is 0 to 1% * [score: 0.0000] Received: from mail.ahsoftware.de (h1446028.stratoserver.net [85.214.92.142]) by yocto-www.yoctoproject.org (Postfix) with ESMTP id 86898E002A8 for ; Fri, 7 Nov 2014 08:39:44 -0800 (PST) Received: by mail.ahsoftware.de (Postfix, from userid 65534) id 850B72C9C201; Fri, 7 Nov 2014 17:39:38 +0100 (CET) Received: from eiche.ahsoftware (p4FC3685E.dip0.t-ipconnect.de [79.195.104.94]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by mail.ahsoftware.de (Postfix) with ESMTPSA id 9715E2C9C1EC for ; Fri, 7 Nov 2014 17:39:37 +0100 (CET) Received: by eiche.ahsoftware (Postfix, from userid 65534) id EE0588E4DB; Fri, 7 Nov 2014 17:39:36 +0100 (CET) Received: from krabat.ahsoftware (unknown [IPv6:feee::5246:5dff:fe8b:95f8]) by eiche.ahsoftware (Postfix) with ESMTP id 746A57F846; Fri, 7 Nov 2014 16:38:15 +0000 (UTC) Message-ID: <545CF576.5050403@ahsoftware.de> Date: Fri, 07 Nov 2014 17:38:14 +0100 From: Alexander Holler User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.7.0 MIME-Version: 1.0 To: Otavio Salvador References: <1415353415-3805-1-git-send-email-holler@ahsoftware.de> <20141107150003.27c16356@e6520eb.localdomain> <20141107160443.765f9b19@e6520eb.localdomain> <545CE3DE.4070902@ahsoftware.de> In-Reply-To: Cc: "meta-freescale@yoctoproject.org" , Jon Nettleton Subject: Re: [PATCH 0/1] arm: imx: fsl_otp: make fuses (OTP memory) read-only X-BeenThere: meta-freescale@yoctoproject.org X-Mailman-Version: 2.1.13 Precedence: list List-Id: Usage and development list for the meta-fsl-* layers List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 07 Nov 2014 16:39:55 -0000 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: quoted-printable Am 07.11.2014 17:00, schrieb Otavio Salvador: > Hello Alexander, > > On Fri, Nov 7, 2014 at 1:23 PM, Alexander Holler = wrote: >> Am 07.11.2014 16:07, schrieb Otavio Salvador: >>> >>> On Fri, Nov 7, 2014 at 1:04 PM, Eric B=C3=A9nard wr= ote: >>>> >>>> Hi Jon, >>>> >>>> Le Fri, 7 Nov 2014 15:31:15 +0100, >>>> Jon Nettleton a =C3=A9crit : >>>>> >>>>> Fair enough. Can we all agree that it should default to disabled? >>>> >>>> >>>> On your product sure, on the evaluation board that's more questionab= le. >>>> >>>> When an evaluation board's user reach this sysfs entries to do a wri= te >>>> to it I believe that's not a random choice but a user's choice. >>>> >>>> Maybe adding a otp_unlock entry to the sysfs before allowing write c= ould >>>> secure more the feature when running on the evaluation boards so tha= t >>>> the user can think twice before writing to the fuses. >>> >>> >>> I like Eric's idea of the unlock sysfs entry for this purpose. >> >> >> Maybe I should mention that this extremly dangerous driver already was= >> posted for submission into the (production) kernel and nobody had a pr= oblem >> with it's write functionality, just with some other stuff. >> >> And even if it's ok for FSL to promote this feature with their BSP, I = have >> absolutely no love for the way it was done. It now is likely part of m= any >> production kernels, something never should have happened. >> >> And I still see absolutely no need to have some one time functionality= as >> part of the kernel, regardless how usefull it might be for some develo= pers. >> It's a waste of time and resources to include that write functionality= in >> something meant for the greater public. Especially something that dang= erous. > > We have two different things here. > > * Linux support: the driver is perfectly capable of handling the > reading and writing > * Driver settings: We should, indeed, have it to be explicitly > enabled on the kernel config to allow writing > > This is done in other areas of kernel (one which comes to my mind is > NTFS Writing support) and what I proposed was you to make: > > CONFIG_FSL_OTP -> read-only > CONFIG_FSL_OTP_WRITE -> write support > > The write support needs to be enabled on mfgtools defconfig and > disabled on regular kernels (this is what I think it should be but it > is up to the board maintainer). Sorry, but based on my experience and confrontations with Murphy I can't = agree. To conclude what already happened: - Someone has written that driver in the way it is. - Several devs likely have seen it before it made it's way into the BSP. - It got enabled by default in the BSP (defconfigs). - It made it's way into YOCTO. - It was submitted for inclusion into the kernel. So the driver already was seen by a lot of people (most likely all devs) = and still nobody has seen a problem. And most of these people did know=20 more about its functionality than most people which are just changing=20 switches in kernel configs or do play with sysfs. And because I don't like to play the bad boy, I'm not going to discuss=20 this any further. I did my part as responsible developer and I think I=20 made my standpoint clear. I hoped it would have happened more silently=20 without that discussion, but ... ;) But feel free to continue this discussion, I don't care if my patch will = be included or not. I just will not modify it. ;) Regards, Alexander Holler