From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jiada Wang Subject: Re: [PATCH 1/1] spi: imx: support to set watermark level via DTS Date: Fri, 6 Jan 2017 01:00:00 -0800 Message-ID: <586F5C90.5070108@mentor.com> References: <20170105061015.7816-1-jiada_wang@mentor.com> <20170105175854.gj5xr5drk5tddzyz@sirena.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit Cc: , , , , To: "Mark Brown vladimir_zapolskiy@mentor.com" Return-path: In-Reply-To: <20170105175854.gj5xr5drk5tddzyz@sirena.org.uk> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-spi.vger.kernel.org Hello Mark and Vladimir On 01/05/2017 09:58 AM, Mark Brown wrote: > On Thu, Jan 05, 2017 at 03:10:15PM +0900, Jiada Wang wrote: > >> Previously watermark level is configured to fifosize/2, >> DMA mode can be used only when transfer length can be divided >> by 'watermark level * bpw', which makes DMA mode not practical. >> This patch adds new DTS property 'dma-wml', user can configure >> DMA watermark level, by specify 'dma-wml' in corresponding ecspi >> node. > Doesn't this just move the problem around a bit - can we not have the > driver figure out a more sensible watermark for each transfer rather > than fixing one in the DT? I would like to submit another version of patch to adjust watermark level based on transfer length. to use largest number (< fifosize / 2 ) which can divide (transfer_length / bytes_per_work). Thanks, Jiada From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jiada Wang Subject: Re: [PATCH 1/1] spi: imx: support to set watermark level via DTS Date: Fri, 6 Jan 2017 01:00:00 -0800 Message-ID: <586F5C90.5070108@mentor.com> References: <20170105061015.7816-1-jiada_wang@mentor.com> <20170105175854.gj5xr5drk5tddzyz@sirena.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20170105175854.gj5xr5drk5tddzyz@sirena.org.uk> Sender: linux-kernel-owner@vger.kernel.org To: "Mark Brown vladimir_zapolskiy@mentor.com" Cc: robh+dt@kernel.org, mark.rutland@arm.com, linux-spi@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org List-Id: devicetree@vger.kernel.org Hello Mark and Vladimir On 01/05/2017 09:58 AM, Mark Brown wrote: > On Thu, Jan 05, 2017 at 03:10:15PM +0900, Jiada Wang wrote: > >> Previously watermark level is configured to fifosize/2, >> DMA mode can be used only when transfer length can be divided >> by 'watermark level * bpw', which makes DMA mode not practical. >> This patch adds new DTS property 'dma-wml', user can configure >> DMA watermark level, by specify 'dma-wml' in corresponding ecspi >> node. > Doesn't this just move the problem around a bit - can we not have the > driver figure out a more sensible watermark for each transfer rather > than fixing one in the DT? I would like to submit another version of patch to adjust watermark level based on transfer length. to use largest number (< fifosize / 2 ) which can divide (transfer_length / bytes_per_work). Thanks, Jiada