From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 DB8FB3B2D1A; Sat, 1 Aug 2026 02:42:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785552149; cv=none; b=SohOXock2b5/7+Xv0jPp0yGUAHyW6NsTmU/1TOdl1LFurzUSTOp4u9wOIew/SXWuhbNa9UqfzDIHYEf/OgByzJAZdQoHKkmJiUwZ3c3jYIreosx6M2tmHyosudvHDZch3YDJwjvNch/24ePAy5dJ/UvNqNlVrB8qY4E+Ew2lOYw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785552149; c=relaxed/simple; bh=DBy8GM64E3L4qowYNbwhnpNAdGzInexudXmTNok3qG8=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=R4C0QJZ060nu8Ks0q0r+LIRoxY52AxLpl2ZGELy0F/JdVBZCyheV6IVlgIGOhxHQxNwGvH+3CfF5bRM83F7SrA1qX9YFh3kvn09DN75WeG+KFyaHkZt1351Z/UU12S3HkCUGN9jB/MPntMBZdPo+A3xGvlybNBeKWLXww8gtUrs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=bl41I0Os; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="bl41I0Os" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3F06E1F00AC4; Sat, 1 Aug 2026 02:42:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1785552147; bh=DBy8GM64E3L4qowYNbwhnpNAdGzInexudXmTNok3qG8=; h=Date:From:To:Cc:Subject:In-Reply-To:References; b=bl41I0OsLNHW0M7Q0trWDplEPQZtiPeklWslt/nnts46swYhaptgF8Y71b3SIhDlk EsHpJ6QVBHfmQ2YZYHASnyAPu1F5unF/ClV813PgdZC9hYcgT7STn2WksxQ3ZONciS hpQBruh6iRRAlv4yasP7IchNvKM5GTZKBxVtGAUkw4lch4mB8OPf9y9DKRPD6EdlXL Wpi0gSFFW//rr6atdjXdWsBW11jOyGqc82Y4ufWX6Txvp6zZOQHwF+15tDqm4rM6Kp uuMNu/hyjHxrZTXMT7M7WWkljo8O2Wt9RYnRSiXTazuQKCusFcWnpIcnVuzBTffggq JWfcRvmZJlbDg== Date: Sat, 1 Aug 2026 03:42:22 +0100 From: Jonathan Cameron To: Frank Li Cc: nuno.sa@analog.com, dmaengine@vger.kernel.org, linux-iio@vger.kernel.org, Vinod Koul , Frank Li , Lars-Peter Clausen , David Lechner , Andy Shevchenko Subject: Re: [PATCH 1/9] dmaengine: Support bus widths of 32 bytes and above Message-ID: <20260801034222.45d4d479@jic23-huawei> In-Reply-To: References: <20260730-dmaengine-support-wider-dma-masks-v1-0-3732f1f9d9ca@analog.com> <20260730-dmaengine-support-wider-dma-masks-v1-1-3732f1f9d9ca@analog.com> X-Mailer: Claws Mail 4.4.0 (GTK 3.24.52; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: dmaengine@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable On Thu, 30 Jul 2026 14:16:30 -0500 Frank Li wrote: > On Thu, Jul 30, 2026 at 03:23:08PM +0100, Nuno S=C3=A1 via B4 Relay wrote: > > [You don't often get email from devnull+nuno.sa.analog.com@kernel.org. = Learn why this is important at https://aka.ms/LearnAboutSenderIdentificatio= n ] > > > > From: Nuno S=C3=A1 > > > > The src_addr_widths and dst_addr_widths capability masks encode each > > supported width as a bit whose position equals the corresponding > > enum dma_slave_buswidth value (e.g. DMA_SLAVE_BUSWIDTH_4_BYTES sets bit > > 4). As these masks are plain u32, widths of 32 bytes and above > > (DMA_SLAVE_BUSWIDTH_32/64/128_BYTES map to bits 32, 64 and 128) cannot > > be represented at all. > > > > Introduce bitmap-based bus width capabilities that span the full enum > > range. To allow DMA controller producers to be converted incrementally, > > keep the legacy dma_device u32 fields alongside the new bitmaps: > > producers using the new helpers populate the bitmap and mirror the low > > 32 bits back into the legacy field, while dma_get_slave_caps() folds a > > legacy-only producer's u32 into the returned bitmap. > > > > Add helpers for producers and consumers so users do not need to depend > > on the bitmap layout directly. Once the remaining producers are > > converted, the legacy dma_device u32 fields can be dropped. > > > > Signed-off-by: Nuno S=C3=A1 > > --- =20 >=20 > Reviewed-by: Frank Li https://sashiko.dev/#/patchset/20260730-dmaengine-support-wider-dma-masks-v= 1-0-3732f1f9d9ca%40analog.com=20 has a comment on this that smells plausible at least. Looks like the stm32 driver modifies dst_bus_widths in it's device_caps() callback. Jonathan