Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755831AbcDKQFN (ORCPT ); Mon, 11 Apr 2016 12:05:13 -0400 Received: from mail-ob0-f178.google.com ([209.85.214.178]:34037 "EHLO mail-ob0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755417AbcDKQFK (ORCPT ); Mon, 11 Apr 2016 12:05:10 -0400 MIME-Version: 1.0 In-Reply-To: References: <1460061433-63750-1-git-send-email-andriy.shevchenko@linux.intel.com> <1460061433-63750-13-git-send-email-andriy.shevchenko@linux.intel.com> <1460388795.19152.38.camel@nexus-software.ie> Date: Mon, 11 Apr 2016 19:05:04 +0300 Message-ID: Subject: Re: [PATCH v1 12/12] serial: 8250_lpss: enable DMA on Intel Quark UART From: Andy Shevchenko To: "Bryan O'Donoghue" , Jarkko Nikula Cc: Andy Shevchenko , Vinod Koul , "linux-kernel@vger.kernel.org" , dmaengine , Greg Kroah-Hartman , "Puustinen, Ismo" , Heikki Krogerus , "linux-serial@vger.kernel.org" Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 955 Lines: 28 On Mon, Apr 11, 2016 at 6:51 PM, Andy Shevchenko wrote: > On Mon, Apr 11, 2016 at 6:33 PM, Bryan O'Donoghue > wrote: >> On Thu, 2016-04-07 at 23:37 +0300, Andy Shevchenko wrote: >> >> Preface. I tried this on Galileo and it appears to work. I'll do some >> throughput testing to verify but, initially the results are positive :) > > I submitted (and pushed into my branch) a bit changed version (see my v2). > >>> + lpss->dma_maxburst = 8; >> >> Are these dwords ? If those are bytes then the maxburst value looks >> small. In the BSP the max burst is 32 bytes. > > max_burst is in items of given size (here is 32 bytes for memory and 8 > bytes for UART). I took this value from Quark BSP, but I'll be happy > to adjust to more optimal values. +Jarkko. Oy vei, seems we don't set memory side of transfer neither in 8250_dma, nor in spi-pxa2xx-dma. -- With Best Regards, Andy Shevchenko