From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C58B7C433EF for ; Wed, 10 Nov 2021 09:59:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A816361207 for ; Wed, 10 Nov 2021 09:59:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231142AbhKJKBq (ORCPT ); Wed, 10 Nov 2021 05:01:46 -0500 Received: from so254-9.mailgun.net ([198.61.254.9]:41406 "EHLO so254-9.mailgun.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229781AbhKJKBn (ORCPT ); Wed, 10 Nov 2021 05:01:43 -0500 DKIM-Signature: a=rsa-sha256; v=1; c=relaxed/relaxed; d=mg.codeaurora.org; q=dns/txt; s=smtp; t=1636538336; h=Content-Transfer-Encoding: Content-Type: MIME-Version: Message-ID: In-Reply-To: Date: References: Subject: Cc: To: From: Sender; bh=fcAghAoVZ0JxeVWaGkjHk7dhQU80Wv79lwRh7/w5leA=; b=Pps+SI9Usj4DJo9TLGSBMBV70h9IVkfkHhuT8I30e966dX0IpuZMB2w9mcg4tuWootjC5fT1 s+s8TZY4eP30DihefZP2YD6/epr+U+2tKG8bEQ8/2O5lFLq95waGm1U1ur8kn2fMlj0ZBe3V Z7bsVaBmSx7Wbwog55zO+R8kQPU= X-Mailgun-Sending-Ip: 198.61.254.9 X-Mailgun-Sid: WyI0MWYwYSIsICJsaW51eC1rZXJuZWxAdmdlci5rZXJuZWwub3JnIiwgImJlOWU0YSJd Received: from smtp.codeaurora.org (ec2-35-166-182-171.us-west-2.compute.amazonaws.com [35.166.182.171]) by smtp-out-n05.prod.us-east-1.postgun.com with SMTP id 618b97db0f34c3436a4a4aab (version=TLS1.2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256); Wed, 10 Nov 2021 09:58:51 GMT Sender: kvalo=codeaurora.org@mg.codeaurora.org Received: by smtp.codeaurora.org (Postfix, from userid 1001) id 8A01DC43616; Wed, 10 Nov 2021 09:58:50 +0000 (UTC) Received: from tykki (tynnyri.adurom.net [51.15.11.48]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) (Authenticated sender: kvalo) by smtp.codeaurora.org (Postfix) with ESMTPSA id 85DE0C4338F; Wed, 10 Nov 2021 09:58:46 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 smtp.codeaurora.org 85DE0C4338F Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; spf=fail smtp.mailfrom=codeaurora.org From: Kalle Valo To: =?utf-8?B?SsOpcsO0bWU=?= Pouiller Cc: linux-wireless@vger.kernel.org, netdev@vger.kernel.org, devel@driverdev.osuosl.org, linux-kernel@vger.kernel.org, Greg Kroah-Hartman , "David S . Miller" , devicetree@vger.kernel.org, Rob Herring , linux-mmc@vger.kernel.org, Pali =?utf-8?Q?Roh?= =?utf-8?Q?=C3=A1r?= , Ulf Hansson Subject: Re: [PATCH v7 05/24] wfx: add main.c/main.h References: <20210920161136.2398632-1-Jerome.Pouiller@silabs.com> <87zgrl86cx.fsf@codeaurora.org> <87v92985ys.fsf@codeaurora.org> <6117440.dvjIZRh6BQ@pc-42> Date: Wed, 10 Nov 2021 11:58:41 +0200 In-Reply-To: <6117440.dvjIZRh6BQ@pc-42> (=?utf-8?B?IkrDqXLDtG1l?= Pouiller"'s message of "Thu, 07 Oct 2021 13:22:14 +0200") Message-ID: <87lf1wnxgu.fsf@codeaurora.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org J=C3=A9r=C3=B4me Pouiller writes: > On Thursday 7 October 2021 12:49:47 CEST Kalle Valo wrote: >> CAUTION: This email originated from outside of the organization. Do >> not click links or open attachments unless you recognize the sender >> and know the content is safe. >>=20 >>=20 >> Kalle Valo writes: >>=20 >> > J=C3=A9r=C3=B4me Pouiller writes: >> > >> >>> >> >> I'm not really fond of having this kind of ASCII based parser = in the >> >>> >> >> kernel. Do you have an example compressed file somewhere? >> >>> >> > >> >>> >> > An example of uncompressed configuration file can be found here= [1]. Once >> >>> >> > compressed with [2], you get: >> >>> >> > >> >>> >> > {a:{a:4,b:1},b:{a:{a:4,b:0,c:0,d:0,e:A},b:{a:4,b:0,c:0,d:0,= e:B},c:{a:4,b:0,c:0,d:0,e:C},d:{a:4,b:0,c:0,d:0,e:D},e:{a:4,b:0,c:0,d:0,e:E= },f:{a:4,b:0,c:0,d:0,e:F},g:{a:4,b:0,c:0,d:0,e:G},h:{a:4,b:0,c:0,d:0,e:H},i= :{a:4,b:0,c:0,d:0,e:I},j:{a:4,b:0,c:0,d:0,e:J},k:{a:4,b:0,c:0,d:0,e:K},l:{a= :4,b:0,c:0,d:1,e:L},m:{a:4,b:0,c:0,d:1,e:M}},c:{a:{a:4},b:{a:6},c:{a:6,c:0}= ,d:{a:6},e:{a:6},f:{a:6}},e:{b:0,c:1},h:{e:0,a:50,b:0,d:0,c:[{a:1,b:[0,0,0,= 0,0,0]},{a:2,b:[0,0,0,0,0,0]},{a:[3,9],b:[0,0,0,0,0,0]},{a:A,b:[0,0,0,0,0,0= ]},{a:B,b:[0,0,0,0,0,0]},{a:[C,D],b:[0,0,0,0,0,0]},{a:E,b:[0,0,0,0,0,0]}]},= j:{a:0,b:0}} >> >>> >> >> >>> >> So what's the grand idea with this braces format? I'm not getting= it. >> >>> > >> >>> > - It allows to describe a tree structure >> >>> > - It is ascii (easy to dump, easy to copy-paste) >> >>> > - It is small (as I explain below, size matters) >> >>> > - Since it is similar to JSON, the structure is obvious to many = people >> >>> > >> >>> > Anyway, I am not the author of that and I have to deal with it. >> >>> >> >>> I'm a supported for JSON like formats, flexibility and all that. But >> >>> they belong to user space, not kernel. >> >>> >> >>> >> Usually the drivers just consider this kind of firmware configura= tion >> >>> >> data as a binary blob and dump it to the firmware, without knowin= g what >> >>> >> the data contains. Can't you do the same? >> >>> > >> >>> > [I didn't had received this mail :( ] >> >>> > >> >>> > The idea was also to send it as a binary blob. However, the firmwa= re use >> >>> > a limited buffer (1500 bytes) to parse it. In most of case the PDS= exceeds >> >>> > this size. So, we have to split the PDS before to send it. >> >>> > >> >>> > Unfortunately, we can't split it anywhere. The PDS is a tree struc= ture and >> >>> > the firmware expects to receive a well formatted tree. >> >>> > >> >>> > So, the easiest way to send it to the firmware is to split the tree >> >>> > between each root nodes and send each subtree separately (see also= the >> >>> > comment above wfx_send_pds()). >> >>> > >> >>> > Anyway, someone has to cook this configuration before to send it t= o the >> >>> > firmware. This could be done by a script outside of the kernel. Th= en we >> >>> > could change the input format to simplify a bit the processing in = the >> >>> > kernel. >> >>> >> >>> I think a binary file with TLV format would be much better, but I'm = sure >> >>> there also other good choises. >> >>> >> >>> > However, the driver has already some users and I worry that changi= ng >> >>> > the input format would lead to a mess. >> >>> >> >>> You can implement a script which converts the old format to the new >> >>> format. And you can use different naming scheme in the new format so >> >>> that we don't accidentally load the old format. And even better if y= ou >> >>> add a some kind of signature in the new format and give a proper err= or >> >>> from the driver if it doesn't match. >> >> >> >> Ok. I am going to change the input format. I think the new function is >> >> going to look like: >> >> >> >> int wfx_send_pds(struct wfx_dev *wdev, u8 *buf, size_t buf_len) >> >> { >> >> int ret; >> >> int start =3D 0; >> >> >> >> if (buf[start] !=3D '{') { >> >> dev_err(wdev->dev, "valid PDS start with '{'. Did you fo= rget to compress it?\n"); >> >> return -EINVAL; >> >> } >> >> while (start < buf_len) { >> >> len =3D strnlen(buf + start, buf_len - start); >> >> if (len > WFX_PDS_MAX_SIZE) { >> >> dev_err(wdev->dev, "PDS chunk is too big (legacy= format?)\n"); >> >> return -EINVAL; >> >> } >> >> dev_dbg(wdev->dev, "send PDS '%s'\n", buf + start); >> >> ret =3D wfx_hif_configuration(wdev, buf + start, len); >> >> /* FIXME: Add error handling here */ >> >> start +=3D len; >> >> } >> >> return 0; >> > >> > Did you read at all what I wrote above? Please ditch the ASCII format >> > completely. >>=20 >> Sorry, I read this too hastily. I just saw "buf[start] !=3D '{'" and >> assumed this is the same ASCII format, but not sure anymore. Can you >> explain what changes you made now? > > The script I am going to write will compute where the PDS have to be split > (this work is currently done by the driver). The script will add a > separating character (let's say '\0') between each chunk. > > The driver will just have to find the separating character, send the > chunk and repeat. I would forget ASCII altogether and implement a proper binary format like TLV. For example, ath10k uses TLV with board-2.bin files (grep for enum ath10k_bd_ie_type). Also I recommend changing the file "signature" ('{') to something else so that the driver detects incorrect formats. And maybe even use suffix .pds2 or something like that to make it more obvious and avoid confusion? --=20 https://patchwork.kernel.org/project/linux-wireless/list/ https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatc= hes