Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752847Ab0HRLY4 (ORCPT ); Wed, 18 Aug 2010 07:24:56 -0400 Received: from smtp0.epfl.ch ([128.178.224.219]:43360 "HELO smtp0.epfl.ch" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1752645Ab0HRLYy convert rfc822-to-8bit (ORCPT ); Wed, 18 Aug 2010 07:24:54 -0400 X-Greylist: delayed 398 seconds by postgrey-1.27 at vger.kernel.org; Wed, 18 Aug 2010 07:24:53 EDT From: Philippe =?iso-8859-1?q?R=E9tornaz?= Organization: EPFL - STI - LSRO1 To: linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH 3/3] dmaengine: Add Freescale i.MX SDMA support Date: Wed, 18 Aug 2010 13:17:48 +0200 User-Agent: KMail/1.12.4 (Linux/2.6.31.13-desktop-1mnb; KDE/4.3.5; x86_64; ; ) Cc: Sascha Hauer , Baruch Siach , Linus Walleij , Dan Williams , "linux-kernel@vger.kernel.org" References: <1281956870-12463-1-git-send-email-s.hauer@pengutronix.de> <20100817043612.GA9631@jasper.tkos.co.il> <20100817064734.GS27749@pengutronix.de> In-Reply-To: <20100817064734.GS27749@pengutronix.de> MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 8BIT Message-Id: <201008181317.48948.philippe.retornaz@epfl.ch> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1883 Lines: 43 Le mardi, 17 ao?t 2010 08.47:34, Sascha Hauer a ?crit : > On Tue, Aug 17, 2010 at 07:36:12AM +0300, Baruch Siach wrote: > > Hi Sascha, > > > > On Mon, Aug 16, 2010 at 04:15:40PM +0200, Sascha Hauer wrote: > > > On Mon, Aug 16, 2010 at 02:21:06PM +0200, Linus Walleij wrote: > > > > 2010/8/16 Sascha Hauer : > > > > > The SDMA engine is a scatter/gather DMA engine which is implemented > > > > > as a seperate coprocessor. SDMA needs its own firmware which is > > > > > requested using the standard request_firmware mechanism. The > > > > > firmware has different entry points for each peripheral type, so > > > > > drivers have to pass the peripheral type to the DMA engine which in > > > > > turn picks the correct firmware entry point from a table contained > > > > > in the firmware image itself. > > > > > > > > Quite fun, if the spec for the microcode is open this opens up > > > > for dynamic firmware generation for specific DMA jobs does it > > > > not? > > > > > > Unfortunately the specs are not open, so we are sticked to the binary > > > microcode from Freescale. I'm pretty sure though that the SDMA engine > > > could do at least a device_prep_dma_xor operation. > > > > Chapter 38 in the i.MX25 Reference Manual seems to include almost > > everything there is to know about the SDMA. Isn't this enough for writing > > custom SDMA microcodes? > > Unfortunately not, the assembler is missing. > I think the instruction list and encoding is available in the imx31 reference manual at section 40.19. BTW, I tested the non-dmaengine version of your patch on imx31, works great ! Regards, Philippe -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/