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 20AF73DFC74; Fri, 15 May 2026 08:00:52 +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=1778832053; cv=none; b=C+DKW+W5NIAzXIpsqjzC0in+l9i9Jrl/mN4lKlL7RalE25QR5lQa/hR6izMllyxHj26VfDDX6SRCevSRY4i9+O9w4jy2KOdlNof2lppNFERSUfB7sXBvKgGadEXiXBUueQ+1d9cF1p68iOyF/a8K0KwEJv4NaM7jiyyUVRyh5Gg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778832053; c=relaxed/simple; bh=OzZj9ylPNNHPLzhxqC6dkIKTlpbmg5YsdZhk+gmhbu0=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Aq9P9uR7QyPRuK9O+y2/cZBTKpoN7FFRF4lLxKNdOXjyqLpoB0f01WeRoWVU4wqZt8HPCVwSKPLdUyqtgcDq6bLAKLLdbkPdGfqgS6hNLiHyip00LBoXwQeGVIGbF8ZAgJ4TzfNK6fV88iL7kscI0/mqV2Ipfr1yAlxC8xrt6EQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=oJp3H6N9; 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="oJp3H6N9" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2AE02C2BCB0; Fri, 15 May 2026 08:00:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1778832052; bh=OzZj9ylPNNHPLzhxqC6dkIKTlpbmg5YsdZhk+gmhbu0=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=oJp3H6N9SjX7yJw/cxlZ31uenc0CjVsA3glhdm1rg3fJQ47kQhtKzgztPliQN2HHl HfGq2ABZ27meKMZdmAM1/M0L3Cpgc+1b78w/0gzNPsB5z651q70CGO2W5kpcGDywP5 4xFz9jN1A5TxJZXrmaylzW5m/Jblmc2Qc7SgzjSRr1AGpT44/AXhnnT82JLuuzzSQt 30fnVIDXEYvE13ma/OnyHA8aILZ7eUEOR0ytRZb+uZLyUDPUEMWCXW2tLIOJoMH1ft j1lsuvlJJRcrzJTdcHOpCbGYKIZUugyArRXPaiZNqzparPjA0PYR3wKxu5zx+BdtNQ 9pg+lJAikdARg== Date: Fri, 15 May 2026 10:00:50 +0200 From: Krzysztof Kozlowski To: Jisheng Zhang Cc: Mark Brown , Rob Herring , Krzysztof Kozlowski , Conor Dooley , linux-spi@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/2] spi: dt-bindings: cdns,xspi: add sdma-io-width Message-ID: <20260515-expert-devious-cricket-faff56@quoll> References: <20260511031732.3199-1-jszhang@kernel.org> <20260511031732.3199-2-jszhang@kernel.org> Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20260511031732.3199-2-jszhang@kernel.org> On Mon, May 11, 2026 at 11:17:31AM +0800, Jisheng Zhang wrote: > The cdns xspi controller SDMA data port may support wider I/O width. > Wider I/O width can benefit performance. A simple test with QSPI nor > flash on one arm64 platform: > > 1 byte io width (default): > # dd if=/dev/mtdblock0 of=/dev/null bs=8192 count=1000 > 1000+0 records in > 1000+0 records out > 8192000 bytes (7.8MB) copied, 1.368735 seconds, 5.7MB/s > > 4 bytes io width: > # dd if=/dev/mtdblock0 of=/dev/null bs=8192 count=1000 > 1000+0 records in > 1000+0 records out > 8192000 bytes (7.8MB) copied, 1.088787 seconds, 7.2MB/s > > Improved by 26.3%! > > Add dt binding for sdma-io-width. > > Signed-off-by: Jisheng Zhang > --- > Documentation/devicetree/bindings/spi/cdns,xspi.yaml | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/Documentation/devicetree/bindings/spi/cdns,xspi.yaml b/Documentation/devicetree/bindings/spi/cdns,xspi.yaml > index 38a5795589de..1fd4b6dfd417 100644 > --- a/Documentation/devicetree/bindings/spi/cdns,xspi.yaml > +++ b/Documentation/devicetree/bindings/spi/cdns,xspi.yaml > @@ -40,6 +40,12 @@ properties: > interrupts: > maxItems: 1 > > + sdma-io-width: > + description: Slave DMA data port I/O width (in bytes) Waht is SDMA? What is Slave DMA? The same? Why this cannot be deduced from the compatible? DMA is fixed per platform and SDMA do not sound like SPI device (so slave in older terminology) property. Anyway, there is generic property reg-io-width if this is for MMIO, bus-width and spi-tx/rx-bus-width. Best regards, Krzysztof