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 gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id F0091CCA470 for ; Wed, 8 Oct 2025 14:28:20 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 3CDD910E848; Wed, 8 Oct 2025 14:28:20 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=gmail.com header.i=@gmail.com header.b="MFAsxLEG"; dkim-atps=neutral Received: from mail-qv1-f47.google.com (mail-qv1-f47.google.com [209.85.219.47]) by gabe.freedesktop.org (Postfix) with ESMTPS id 4676F10E83C for ; Wed, 8 Oct 2025 14:28:19 +0000 (UTC) Received: by mail-qv1-f47.google.com with SMTP id 6a1803df08f44-7900f7f4ba9so72564126d6.0 for ; Wed, 08 Oct 2025 07:28:19 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1759933698; x=1760538498; darn=lists.freedesktop.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=C3nyMQNps0AyLL97xzttuk+phB0DdoZh7JjDzOjB4po=; b=MFAsxLEGjCRTAdsXcqihNtVC6waBb8ZYlCNYSdQlhMwUM8A83fJpW0lpgIPTODBtrk FPjjNaKjD24dI8fbVDpcBBhTT90YCn6fwVMnrGk/HnQ2STGx2tMi1O+dNb+/AkunXV+b mFx8+0o8LMkIglLKMAgUU5lXRWpOXFIjCMqlB+aGYrT7Mg3TgTspT4+nJsqAthqvb9Gi ODmc78XC2Jn1v69t7tTqVyFIHmkVWlPxCGyeCWy6CCITohfuwoQk8yyjvwox9D7W8SY0 N+sHpM7qiv/TSrdYendR4j5ss/Op4gypgH8on+NiAH/ci1naS2PHbfHNZdE9+rrmB5D7 5qNQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1759933698; x=1760538498; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=C3nyMQNps0AyLL97xzttuk+phB0DdoZh7JjDzOjB4po=; b=M58a97fDzxJgpfgg6IQ4MWpPBz5u10ooUyrBzHZBQCjQoAme3SLAXdFdzyDM5k52ja Sz4Gqh6EmcrGQfWAwWN67y3Goca5ukbI7LKqDVUYey1QTjmMBwD4lvk5DEGNIDLxoAKj U1/1W4B++By6SSIss1uVPgOljai3lOT/fANKkwFDrhwKExMtv3QCbe+vI/MhgVo3roKu YUP1KLSiTG7Z9dh8TcTk3yzLRxj/JyeOPenerN11FtiwT4omC5fOJNN+2IvwUHuVRJog 6MGNfWkNsyNucPx+Td1SxrDmATXYPaZMrk+K9cgpp/SlHMqYkuOVMkmc/L0uVXGrr6pk YvEA== X-Forwarded-Encrypted: i=1; AJvYcCUvMNCEBuHKgvVs/3zLCoxvu9Zf/XR5I7hzFyl+0zKyaB96hFwgOjU86oUaSpiHbMYYUWrZkS26Y0M=@lists.freedesktop.org X-Gm-Message-State: AOJu0Yz6EGC2vEkKxj/M87hbYM6aLASBBxbG1PtoKyXdyOGy6alQE8tG tffPfrv6ryst0X7OgKvuDPsB/Hc7lB/WD/n3OgkEImNMFmQ6bLRBP/2q X-Gm-Gg: ASbGncuMFtMFzilpicEolWXQ7giGIFkVFnKmg19D2ASPB/6JxwL8a5bQFFR4Aj9aQ8L CZrgG4ys9P+wawJMRRKW2J3IsQbYvCAK6yZ1ni83kqi8y+M746opnC2boJBxS/6nEJs2a14LHuu nqZaDnW7HLMCV0OKq6qjhzIkXyKlMeAqO+FF3p3DDnTv26xERbh6UCU6LCQuAfw/8YmUWGUyr9v p83grocHyMkN6UejUUcOkPlsVqPZJ6MiKM+aCqdWpwaknVgfo1mybKTo2x3h6iL1OgSiVPXAF4J R5Lln4DtMTGqY8aEAmtJMUp+D/PSFgygrLuYDpsOEsz4aJjMFJX4rCQEPUP7fAfxR4qfpLjf2Mx 3aLmylXicxd5hJ+GBhHN3lTHAQzeojpaOJccNRVp8Pwg= X-Google-Smtp-Source: AGHT+IFntZefp3Ss0mi+6jECEAXuwb7eOj/bzue7nh8gRQKVbgbOiMWHYq2oEKWHI2USmbbKcqsDDg== X-Received: by 2002:a05:6214:2a87:b0:789:d698:d384 with SMTP id 6a1803df08f44-87b2103104bmr48809406d6.20.1759933697907; Wed, 08 Oct 2025 07:28:17 -0700 (PDT) Received: from localhost ([12.22.141.131]) by smtp.gmail.com with ESMTPSA id 6a1803df08f44-878be61f6bcsm163723216d6.65.2025.10.08.07.28.16 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 08 Oct 2025 07:28:17 -0700 (PDT) Date: Wed, 8 Oct 2025 10:28:15 -0400 From: Yury Norov To: Danilo Krummrich Cc: Joel Fernandes , Alexandre Courbot , linux-kernel@vger.kernel.org, rust-for-linux@vger.kernel.org, dri-devel@lists.freedesktop.org, Alistair Popple , Miguel Ojeda , Alex Gaynor , Boqun Feng , Gary Guo , bjorn3_gh@protonmail.com, Benno Lossin , Andreas Hindborg , Alice Ryhl , Trevor Gross , David Airlie , Simona Vetter , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , John Hubbard , Timur Tabi , joel@joelfernandes.org, Elle Rhumsaa , Daniel Almeida , Andrea Righi , nouveau@lists.freedesktop.org Subject: Re: [PATCH v6 0/5] Introduce bitfield and move register macro to rust/kernel/ Message-ID: References: <20251003154748.1687160-1-joelagnelf@nvidia.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" On Wed, Oct 08, 2025 at 12:08:59AM +0200, Danilo Krummrich wrote: > Regarding the bitfields for page table management: Are we > sure that we can use raw bitfields for this? As per my current understanding we can't. Bitfields are not suitable for direct I/O and considered as a data storage. In the current scheme: regs::NV_PFALCON_FALCON_DMATRFBASE::default() .set_base((dma_start >> 8) as u32) .write(bar, &E::ID); we account for endianess in the .write() method, which would be a part of register API, not bitfields. FYI: ARM64 is in process of dropping BE, and Linus announced the end of BE support for RISC-V: https://lore.kernel.org/all/CAHk-=wgYcOiFvsJzFb+HfB4n6Wj6zM5H5EghUMfpXSCzyQVSfA@mail.gmail.com/ Thanks, Yury