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Date:   Wed, 13 May 2020 09:20:13 +0200
From:   Sascha Hauer <s.hauer@pengutronix.de>
To:     Robin Gong <yibin.gong@nxp.com>
Cc:     vkoul@kernel.org, shawnguo@kernel.org,
        u.kleine-koenig@pengutronix.de, robh+dt@kernel.org,
        festevam@gmail.com, dan.j.williams@intel.com, mark.rutland@arm.com,
        catalin.marinas@arm.com, will.deacon@arm.com,
        l.stach@pengutronix.de, martin.fuzzey@flowbird.group,
        kernel@pengutronix.de, linux-spi@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        linux-imx@nxp.com, dmaengine@vger.kernel.org,
        devicetree@vger.kernel.org
Subject: Re: [PATCH v7 RESEND 00/13] add ecspi ERR009165 for i.mx6/7 soc
 family
Message-ID: <20200513072012.GB15934@pengutronix.de>
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On Tue, May 12, 2020 at 01:32:23AM +0800, Robin Gong wrote:
> There is ecspi ERR009165 on i.mx6/7 soc family, which cause FIFO
> transfer to be send twice in DMA mode. Please get more information from:
> https://www.nxp.com/docs/en/errata/IMX6DQCE.pdf. The workaround is adding
> new sdma ram script which works in XCH  mode as PIO inside sdma instead
> of SMC mode, meanwhile, 'TX_THRESHOLD' should be 0. The issue should be
> exist on all legacy i.mx6/7 soc family before i.mx6ul.
> NXP fix this design issue from i.mx6ul, so newer chips including i.mx6ul/
> 6ull/6sll do not need this workaroud anymore. All other i.mx6/7/8 chips
> still need this workaroud. This patch set add new 'fsl,imx6ul-ecspi'
> for ecspi driver and 'ecspi_fixed' in sdma driver to choose if need errata
> or not.
> The first two reverted patches should be the same issue, though, it
> seems 'fixed' by changing to other shp script. Hope Sean or Sascha could
> have the chance to test this patch set if could fix their issues.
> Besides, enable sdma support for i.mx8mm/8mq and fix ecspi1 not work
> on i.mx8mm because the event id is zero.

It's not nice to break SPI support when the new firmware is not present
and I think we can do better. Wouldn't it be possible to fall back to PIO
in this case?

Sascha

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