Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751740AbdHRKpH (ORCPT ); Fri, 18 Aug 2017 06:45:07 -0400 Received: from metis.ext.4.pengutronix.de ([92.198.50.35]:60103 "EHLO metis.ext.4.pengutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750988AbdHRKpF (ORCPT ); Fri, 18 Aug 2017 06:45:05 -0400 Date: Fri, 18 Aug 2017 12:45:01 +0200 From: Oleksij Rempel To: Jiada Wang Cc: broonie@kernel.org, s.hauer@pengutronix.de, linux-spi@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH linux-next v5 1/1] spi: imx: dynamic burst length adjust for PIO mode Message-ID: <20170818104500.ixuiy7ghvyuavbdh@pengutronix.de> References: <20170810045008.7532-1-jiada_wang@mentor.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170810045008.7532-1-jiada_wang@mentor.com> X-Sent-From: Pengutronix Hildesheim X-URL: http://www.pengutronix.de/ X-IRC: #ptxdist @freenode X-Accept-Language: de,en X-Accept-Content-Type: text/plain X-Uptime: 12:40:03 up 68 days, 22:38, 198 users, load average: 3,60, 5,89, 4,29 User-Agent: NeoMutt/20170609 (1.8.3) X-SA-Exim-Connect-IP: 2001:67c:670:100:1d::7 X-SA-Exim-Mail-From: ore@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-kernel@vger.kernel.org Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 848 Lines: 19 On Thu, Aug 10, 2017 at 01:50:08PM +0900, Jiada Wang wrote: > > previously burst length (BURST_LENGTH) is always set to equal > to bits_per_word, causes a 10us gap between each word in > transfer, which significantly affects performance. > > This patch uses 32 bits transfer to simulate lower bits transfer, > and adjusts burst length runtimely to use biggeest burst length > as possible to reduce the gaps in transfer for PIO mode. > > Signed-off-by: Jiada Wang Tested-by: Oleksij Rempel -- Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |