From: Martin Kaiser <martin@kaiser.cx>
To: "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>
Cc: imx@lists.linux.dev,
Alexander Stein <alexander.stein@ew.tq-group.com>,
Fabio Estevam <festevam@gmail.com>,
Sascha Hauer <s.hauer@pengutronix.de>,
linux-spi@vger.kernel.org, Mark Brown <broonie@kernel.org>,
Pengutronix Kernel Team <kernel@pengutronix.de>,
Francesco Dolcini <francesco.dolcini@toradex.com>,
Shawn Guo <shawnguo@kernel.org>,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] spi: imx: Don't expect DMA for i.MX{25, 35, 50, 51, 53} cspi devices
Date: Wed, 15 May 2024 21:26:17 +0200 [thread overview]
Message-ID: <ZkUMWWcEpLvE3b-J@akranes.kaiser.cx> (raw)
In-Reply-To: <ZkDq73W7MuyQ4RLj@akranes.kaiser.cx>
Thus wrote Martin Kaiser (martin@kaiser.cx):
> > However this breaks SPI transfers, when I try to read out an MRAM I get:
> > root@ecu02:~ hexdump -C /dev/mtd4
> > [ 71.813807] spi_imx 43fa4000.spi: I/O Error in DMA TX
> > [ 71.819173] spi-nor spi0.2: SPI transfer failed: -110
> > [ 71.829129] spi_master spi0: failed to transfer one message from queue
> > [ 71.843962] spi_master spi0: noqueue transfer failed
> > So it would indeed be interesting if you ever managed to use DMA on
> > i.MX25.
> I believe so. Looking into my notes from 2016 (when I last tried this), I got
> the -110 error when the SMC bit in CONREG wasn't set. But this should now be
> done in mx31_prepare_transfer if DMA is used...
> I'll try to set up a test some time next week.
I can now reproduce the dma tx error. My test board uses a dummy spidev device
on cspi1 and configures loopback on the cspi1 controller (disabling loopback
makes no difference).
I'm relatively sure that this setup did work back in 2016/17.
Commit 24bb244e02a6 ("ARM: i.MX25: globally disable supervisor protect") was
required before any DMA transfers started working on imx25. As far as I can
see, this code is still present.
I'll look into this a bit more as time permits.
Martin
prev parent reply other threads:[~2024-05-15 19:26 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-08 9:56 [PATCH] spi: imx: Don't expect DMA for i.MX{25,35,50,51,53} cspi devices Uwe Kleine-König
2024-05-08 13:44 ` Martin Kaiser
2024-05-10 12:32 ` [PATCH] spi: imx: Don't expect DMA for i.MX{25, 35, 50, 51, 53} " Uwe Kleine-König
2024-05-10 13:40 ` Uwe Kleine-König
2024-05-12 16:14 ` Martin Kaiser
2024-05-15 19:26 ` Martin Kaiser [this message]
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