From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B0F2131814B; Fri, 15 Aug 2025 17:11:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755277874; cv=none; b=HBntlxAlZ4KGNL+GmF83s2b34Zh89mRfhNFDrI+mrx42upTK3wI5yw+wcuFYfjqPPRVLL5UyEVSJ8MG+G0rzIEdQ9BGozBijKdKT/GvxQ3/r9d5w1FCh6eoIgg/DcM8qaSsGGrKHtEfURAHJkpwfjdvnBuNE3jltAtVU9sezeLw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755277874; c=relaxed/simple; bh=5GF/fPBri3zusHWMYumFRlNhCGJGYDbHoq1k0jnDBy0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=L1Kg3QucpiVxrs1HS1OOADlrKUFFjXZIUFH999jF1jIUUZY5rE1A9CtwnR7YLn0EncoJF9qOjDmqTbaISC/ZeeAnWwFrnLKo5mSBHfPYWHlXCNAuWvSCPvmW2sOcqibYl+VukMGpVpiXfqS362tg0R0OHgSNjtf+uJL60DPl8Eg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=u7+T4Iw9; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="u7+T4Iw9" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7EAD5C4CEF1; Fri, 15 Aug 2025 17:11:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1755277874; bh=5GF/fPBri3zusHWMYumFRlNhCGJGYDbHoq1k0jnDBy0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=u7+T4Iw9C0jUNglh534nlG6bA1LnmWp/y687grWwGYK2DPVCZdnf/PmXySdia6At3 +E6w8OpFhW554Rns/vDIrv65ozsiCb/8U1P+V6TScdRmaiGchIm6d0mpYakq/CaE1R HZeWcK5vnUXqP+u9Mu5gvvVibipC+wDzOpMI7SKIucA/gzzStb+TzeBlOnfcWg7TAH 28xCIyDQLcNbvQYL+nnZ+MR4ZWrVEyop12glfvCvTkBk/3ilZe0b6EbUTMRGKJox+C bpIeGiw/fnTy3OoPzXiOpbyQyvC2C9IA0JkXacKnm5Wj1YpTi+x3rv4/S+MZAxNtnc yhMpNWsz2IVew== From: Danilo Krummrich To: akpm@linux-foundation.org, ojeda@kernel.org, alex.gaynor@gmail.com, boqun.feng@gmail.com, gary@garyguo.net, bjorn3_gh@protonmail.com, lossin@kernel.org, a.hindborg@kernel.org, aliceryhl@google.com, tmgross@umich.edu, abdiel.janulgue@gmail.com, acourbot@nvidia.com, jgg@ziepe.ca, lyude@redhat.com, robin.murphy@arm.com, daniel.almeida@collabora.com Cc: rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org, Danilo Krummrich Subject: [PATCH 1/4] rust: dma: implement DataDirection Date: Fri, 15 Aug 2025 19:10:02 +0200 Message-ID: <20250815171058.299270-2-dakr@kernel.org> X-Mailer: git-send-email 2.50.1 In-Reply-To: <20250815171058.299270-1-dakr@kernel.org> References: <20250815171058.299270-1-dakr@kernel.org> Precedence: bulk X-Mailing-List: rust-for-linux@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Add the `DataDirection` struct, a newtype wrapper around the C `enum dma_data_direction`. This provides a type-safe Rust interface for specifying the direction of DMA transfers. Signed-off-by: Danilo Krummrich --- rust/bindings/bindings_helper.h | 1 + rust/kernel/dma.rs | 41 +++++++++++++++++++++++++++++++++ 2 files changed, 42 insertions(+) diff --git a/rust/bindings/bindings_helper.h b/rust/bindings/bindings_helper.h index 0e140e07758b..c2cc52ee9945 100644 --- a/rust/bindings/bindings_helper.h +++ b/rust/bindings/bindings_helper.h @@ -47,6 +47,7 @@ #include #include #include +#include #include #include #include diff --git a/rust/kernel/dma.rs b/rust/kernel/dma.rs index 2bc8ab51ec28..b0950a2768a5 100644 --- a/rust/kernel/dma.rs +++ b/rust/kernel/dma.rs @@ -244,6 +244,47 @@ pub mod attrs { pub const DMA_ATTR_PRIVILEGED: Attrs = Attrs(bindings::DMA_ATTR_PRIVILEGED); } +/// DMA data direction. +/// +/// Corresponds to the C [`enum dma_data_direction`]. +/// +/// [`enum dma_data_direction`]: srctree/include/linux/dma-direction.h +#[derive(Copy, Clone, PartialEq, Eq)] +pub struct DataDirection(bindings::dma_data_direction); + +impl DataDirection { + /// The DMA mapping is for bidirectional data transfer. + /// + /// This is used when the buffer can be both read from and written to by the device. + /// The cache for the corresponding memory region is both flushed and invalidated. + pub const BIDIRECTIONAL: DataDirection = + DataDirection(bindings::dma_data_direction_DMA_BIDIRECTIONAL); + + /// The DMA mapping is for data transfer from memory to the device (write). + /// + /// The CPU has prepared data in the buffer, and the device will read it. + /// The cache for the corresponding memory region is flushed. + pub const TO_DEVICE: DataDirection = DataDirection(bindings::dma_data_direction_DMA_TO_DEVICE); + + /// The DMA mapping is for data transfer from the device to memory (read). + /// + /// The device will write data into the buffer for the CPU to read. + /// The cache for the corresponding memory region is invalidated before CPU access. + pub const FROM_DEVICE: DataDirection = + DataDirection(bindings::dma_data_direction_DMA_FROM_DEVICE); + + /// The DMA mapping is not for data transfer. + /// + /// This is primarily for debugging purposes. With this direction, the DMA mapping API + /// will not perform any cache coherency operations. + pub const NONE: DataDirection = DataDirection(bindings::dma_data_direction_DMA_NONE); + + /// Returns the raw representation of [`enum dma_data_direction`]. + pub fn as_raw(self) -> bindings::dma_data_direction { + self.0 + } +} + /// An abstraction of the `dma_alloc_coherent` API. /// /// This is an abstraction around the `dma_alloc_coherent` API which is used to allocate and map -- 2.50.1