From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751438AbaFEJqs (ORCPT ); Thu, 5 Jun 2014 05:46:48 -0400 Received: from mga03.intel.com ([143.182.124.21]:57838 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750833AbaFEJqr (ORCPT ); Thu, 5 Jun 2014 05:46:47 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.98,980,1392192000"; d="scan'208";a="441186874" Date: Thu, 5 Jun 2014 12:46:42 +0300 From: Mika Westerberg To: Chew Chiau Ee Cc: Mark Brown , Eric Miao , Russell King , Haojian Zhuang , linux-arm-kernel@lists.infradead.org, linux-spi@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] spi/pxa2xx: change default supported DMA burst size to 1 Message-ID: <20140605094642.GJ5214@lahna.fi.intel.com> References: <1401990309-12492-1-git-send-email-chiau.ee.chew@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1401990309-12492-1-git-send-email-chiau.ee.chew@intel.com> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jun 06, 2014 at 01:45:09AM +0800, Chew Chiau Ee wrote: > From: Chew, Chiau Ee > > This is to fix the SPI DMA transfer failure for speed less than 1M. > If using current DMA burst size setting (16), the Rx data bytes are > invalid due to each data byte is multiplied according to the burst > size setting. > > Let's said supposedly we shall receive the following 18 bytes of data: > 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 > Instead, the data bytes received consist of "16 bytes of '01' + > 2 bytes of '02'" : > 01 01 01 01 01 01 01 01 01 01 01 01 01 01 01 01 02 02 > > Signed-off-by: Chew, Chiau Ee > Cc: Mika Westerberg Works for me (and individual chips can tune this by passing custom dma_burst_size if needed). Acked-by: Mika Westerberg