From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dirk Behme Subject: Re: [PATCH] i.MX SPI DMA cleanup Date: Wed, 17 Feb 2016 15:10:44 +0100 Message-ID: <56C47F64.1080706@de.bosch.com> References: <1455715739-25161-1-git-send-email-s.hauer@pengutronix.de> <56C478C9.6050706@de.bosch.com> <20160217135441.GA3939@pengutronix.de> Mime-Version: 1.0 Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Transfer-Encoding: 7bit Cc: , Mark Brown , Shawn Guo , To: Sascha Hauer Return-path: In-Reply-To: <20160217135441.GA3939-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org> Sender: linux-spi-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: On 17.02.2016 14:54, Sascha Hauer wrote: > Hi Dirk, > > On Wed, Feb 17, 2016 at 02:42:33PM +0100, Dirk Behme wrote: >> Hi Sascha, >> >> On 17.02.2016 14:28, Sascha Hauer wrote: >>> This picks up a series sent by Anton Bondarenko last year. It >>> contains the remaining not yet upstreamed patches from Antons series >>> plus some more DMA related cleanup patches. >>> >>> My mission was to hunt a bug in the DMA code path sometimes causing >>> an additional word in the RX FIFO which locked up the driver in the >>> next transfer. It turned out that this was no bug in the driver but >>> instead in the device tree: We used the wrong SDMA script for i.MX6. >>> The ECSPI cores are connected through the SPBA, so according to the >>> reference manual we need the shp/mcu scripts rather than the app/mcu >>> scripts. >> >> >> Are you talking about what is known as "TKT238285 hardware issue" >> >> https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/drivers/spi/spi-imx.c?id=a02bb401f8ae264be782ee57d98bdd99f14c8022 > > I am aware of this issue, but I have no idea if this is the same or > another issue. It says: > >> For TKT238285 hardware issue which may cause txfifo store data twice can only >> be caught on i.mx6dl, we use pio mode instead of DMA mode on i.mx6dl. > > What I saw here is that there was one word more than expected in the RX > FIFO. Since both RX and TX FIFO act synchronously it could be that the > additional word in the RX FIFO was caused by an additional word in the > TX FIFO as described above. The question behind all this is if we could drop https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/drivers/spi/spi-imx.c?id=a02bb401f8ae264be782ee57d98bdd99f14c8022 ? And/Or if/how we like to import the FSL workaround for TKT238285 http://git.freescale.com/git/cgit.cgi/imx/linux-2.6-imx.git/commit/?h=imx_3.14.38_6qp_ga&id=646a751a4d1d0e227a762b461d9b8f92605c26b1 http://git.freescale.com/git/cgit.cgi/imx/linux-2.6-imx.git/commit/?h=imx_3.14.38_6qp_ga&id=01f180af19a7d5c6f5abc51218be93ea4b5d68ff http://git.freescale.com/git/cgit.cgi/imx/linux-2.6-imx.git/commit/?h=imx_3.14.38_6qp_ga&id=321beb210ffb382b8b5378cbf4467f8986efd52f ? Best regards Dirk -- To unsubscribe from this list: send the line "unsubscribe linux-spi" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html