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 78D3B25742F; Wed, 20 May 2026 07:09:59 +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=1779261000; cv=none; b=kXKN1CQNTG6OzBUxMMNkxfhX42VdlWOsUpyv+5WmX3RitGkySYUlOfcT5AtFxv5RTfwhRuT+75HkPlD7vgHzHYWZXHylwUP7IZdfekAiTZfM/FBw5OdyJfGjVIzS2NeZBQm1pGGy/3fouDfKwa7Om9DWfBOv5GE5t1RlzWIg5M0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779261000; c=relaxed/simple; bh=9IViVaf+Wszx8ZhNtH9hghH9H9OH40GFse+I8qT/1M4=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=pgj8TlWVG7MzAhagCsTcKju38h6xCC3IWV52UqT6aOgciSHr2DUk1ws0XIIxEq0BThs/EBhelb7Ybgt/HQE1C6WsyS7fQWpci+oEU3l5ooXvbeAi5lPP3rMA6k9bGBEELNixFCduTM8kh4W9JFNG+XozW+9LB/TfFmEngPk4+ew= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=lxM6tUI3; 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="lxM6tUI3" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3C92E1F000E9; Wed, 20 May 2026 07:09:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1779260999; bh=yCEx1ZgD7hquCJpA2zMjQAl8AHM2PWKyoyzhPNTgAHg=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=lxM6tUI3fPPhuJL503kwN3wymSlUNBBp5VUdvmUfbJgD1EfZBKNcsWDx+f/sxenPF GAcEi//fkRN/z9vSVfD0bLajEk6UcICb61Do/Jo1WOOB+m9Hl59Z//c43/qAiTL7ZB c4PGZtF9g4+u/6eNBSxkEiiHIVNZhS7wEvJK4pN1a5IJhcvEzpMejHomlldBSbDPGj ph2vYyAb10bmPuwvopL4YtShZvcE6ksLi+MkRPP9G0KkHFea6s1DjO8uBIMt3y5+4K d1aDrhDZQq2nhuGN+QVK/dK8ZppS6cQ5lgHfX3sv2M2hilDrzKNMKWAgMCQ5IeiHsM 5lnE/svX97DaQ== Message-ID: <21d30826-bfe6-44cd-8c89-c1986f539e48@kernel.org> Date: Wed, 20 May 2026 09:09:55 +0200 Precedence: bulk X-Mailing-List: linux-spi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 1/2] spi: dt-bindings: cdns,xspi: add sdma-io-width 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 References: <20260511031732.3199-1-jszhang@kernel.org> <20260511031732.3199-2-jszhang@kernel.org> <20260515-expert-devious-cricket-faff56@quoll> From: Krzysztof Kozlowski Content-Language: en-US Autocrypt: addr=krzk@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit On 20/05/2026 01:38, Jisheng Zhang wrote: > On Fri, May 15, 2026 at 10:00:50AM +0200, Krzysztof Kozlowski wrote: >> 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. > > in cdns xspi, sdma == slave dma. It can be read by any master, such > as DMA engine or CPU. Its purpose and usage is similar as the data > reg in other spi controllers, e.g the DW_SPI_DR in dw spi. You did not really answer the questions. Best regards, Krzysztof