From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vignesh R Subject: Re: [PATCH 1/5] spi: introduce mmap read support for spi flash devices Date: Wed, 16 Sep 2015 15:38:09 +0530 Message-ID: <55F93F89.7060708@ti.com> References: <1441355402-6837-1-git-send-email-vigneshr@ti.com> <1441355402-6837-2-git-send-email-vigneshr@ti.com> <20150914183744.GF12027@sirena.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20150914183744.GF12027@sirena.org.uk> Sender: linux-kernel-owner@vger.kernel.org To: Mark Brown Cc: Benoit Cousson , Tony Lindgren , Russell King , David Woodhouse , Brian Norris , hramrach@gmail.com, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-omap@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mtd@lists.infradead.org, linux-spi@vger.kernel.org List-Id: devicetree@vger.kernel.org On 09/15/2015 12:07 AM, Mark Brown wrote: > On Fri, Sep 04, 2015 at 01:59:58PM +0530, Vignesh R wrote: >> In addition to providing direct access to SPI bus, some spi controller >> hardwares (like ti-qspi) provide special memory mapped port >> to accesses SPI flash devices in order to increase read performance. >> This means the controller can automatically send the SPI signals >> required to read data from the SPI flash device. > > Sorry, also meant to say here: as I kind of indicated in response to the > flash patch I'd expect to see the SPI core know something about this and > export an API for this which is integrated with things like the existing > message queue. > Adding an API to SPI core makes sense to me. This can take care of spi bus locking and runtime pm. But, I didn't get how to integrate with existing message queue. Memory mapped read by-passes message queue of SPI core. Could you please explain a bit more on integrating with message queue? Did you mean locking the existing message queue when memory mapped read is being requested? Thanks, Vignesh