From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Krishna Prasad Herur" Subject: RE: DMA transfer using McSPI driver Date: Wed, 31 Jan 2007 09:10:34 -0800 Message-ID: References: <46149.192.168.10.89.1170250434.squirrel@dbdmail.itg.ti.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Return-path: Content-class: urn:content-classes:message In-Reply-To: <46149.192.168.10.89.1170250434.squirrel@dbdmail.itg.ti.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-omap-open-source-bounces@linux.omap.com Errors-To: linux-omap-open-source-bounces@linux.omap.com To: girishsg@ti.com Cc: linux-omap-open-source@linux.omap.com List-Id: linux-omap@vger.kernel.org Thanks Girish, I had made a "Linux newbie" mistake. I was passing in an address in virtual memory, which caused a DMA transaction error. Works much better when I pass the physical address. I may need to do a few cache flushes to get the actual data out, but I do not see the resets anymore. Thanks again. -Prasad -----Original Message----- From: Girish. S. G. [mailto:girishsg@ti.com]=20 Sent: Wednesday, January 31, 2007 5:34 AM To: Krishna Prasad Herur Cc: linux-omap-open-source@linux.omap.com Subject: RE: DMA transfer using McSPI driver hi prasad, If you have called all config macros correctly (like, set and get transmission enable on line 1/0 etc,.) then there shoudn't b any problem. Just check once if you are allocating memory for DMA buf properly. regards, girish > I think I know the reason for the soft lockup. > > The omap 2430 errata says that the DMA Tx complete interrupt continues > to be asserted after a transaction error. I found this to be the reason > for the soft lockup. I am still unsure as to why there is a transaction > error! > > > > The McSpi driver configuration for DMA transfer seems to be > straightforward. The McSpi driver seems to be calling all the Dma driver > functions with the right parameters. > > > > Does anyone had success doing DMA transfers to/from McSpi channels using > the Omap McSpi driver? > > Regards, > > -Prasad > > > > ________________________________ > > From: Krishna Prasad Herur > Sent: Tuesday, January 23, 2007 12:02 PM > To: linux-omap-open-source@linux.omap.com > Subject: DMA transfer using McSPI driver > > > > Hi Gurus, > > I was able to get raw data transfers over the McSPI bus on > an Omap 2430 based platform running Linux 2.6. I am trying to do the > same transmit using DMA. Is it possible to use DMA in polling mode? I > have not registered interrupt handlers or dma handlers. Below is the > programming sequence I followed, after calling all the config macros. > > > > omap2_mcspi_request_interface(devPtr); > > omap2_mcspi_interface_reset(devPtr); > > omap2_mcspi_get(devPtr); > > omap2_mcspi_config_channel(devPtr); > > omap2_mcspi_enable_channel(devPtr); > > omap2_mcspi_dma_writereq(devPtr,OMAP2_McSPI_DMAW_ENABLE); > > omap2_mcspi_transmit_buf(devPtr,dmaBuf,8); > > > > I get a DMA transaction error, and a soft lockup. > > > > DMA transaction error occurred with device 35 > > BUG: soft lockup detected on CPU#0! > > > > Regards, > > -Prasad > > _______________________________________________ > Linux-omap-open-source mailing list > Linux-omap-open-source@linux.omap.com > http://linux.omap.com/mailman/listinfo/linux-omap-open-source >