linux-kernel - Re: [PATCH v5 11/15] dmaengine: imx-sdma: fix ecspi1 rx dma not work on i.mx8mm

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Date:   Wed, 25 Sep 2019 14:53:29 +0000
From:   Schrempf Frieder <frieder.schrempf@...tron.de>
To:     Robin Gong <yibin.gong@....com>
CC:     "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>,
        "vkoul@...nel.org" <vkoul@...nel.org>,
        "dan.j.williams@...el.com" <dan.j.williams@...el.com>,
        "shawnguo@...nel.org" <shawnguo@...nel.org>,
        "s.hauer@...gutronix.de" <s.hauer@...gutronix.de>,
        Pengutronix Kernel Team <kernel@...gutronix.de>,
        Fabio Estevam <festevam@...il.com>,
        dl-linux-imx <linux-imx@....com>,
        "dmaengine@...r.kernel.org" <dmaengine@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-spi@...r.kernel.org" <linux-spi@...r.kernel.org>
Subject: Re: [PATCH v5 11/15] dmaengine: imx-sdma: fix ecspi1 rx dma not work
 on i.mx8mm

On 25.09.19 13:26, Robin Gong wrote:
> On 2019-9-24 21:28 Schrempf Frieder <frieder.schrempf@...tron.de> wrote:
>>
>> Hi Robin,
>>
>>> From: Robin Gong <yibin.gong at nxp.com>
>>>
>>> Because the number of ecspi1 rx event on i.mx8mm is 0, the condition
>>> check ignore such special case without dma channel enabled, which
>>> caused
>>> ecspi1 rx works failed. Actually, no need to check event_id0/event_id1
>>> and replace checking 'event_id1' with 'DMA_DEV_TO_DEV', so that
>>> configure
>>> event_id1 only in case DEV_TO_DEV.
>>>
>>> Signed-off-by: Robin Gong <yibin.gong at nxp.com>
>>> Acked-by: Vinod Koul <vkoul at kernel.org>
>>
>> I have a custom board with i.MX8MM and SPI flash on ecspi1. I'm currently
>> testing with v5.3 and as SPI didn't work, I tried two different things:
>>
>> 1. Removing 'dmas' and 'dma-names' from the ecspi1 node in imx8mm.dtsi,
>>      to use PIO instead of DMA. This works as expected and the driver
>>      boots with the following messages:
>>
>>          spi_imx 30820000.spi: dma setup error -19, use pio
>>          m25p80 spi0.0: mx25v8035f (1024 Kbytes)
>>          spi_imx 30820000.spi: probed
>>
>> 2. Applying your patchset and use DMA. In this case, the flash also
>>      works fine, but there are some error messages printed while booting:
>>
>>          spi_master spi0: I/O Error in DMA RX
>>          m25p80 spi0.0: SPI transfer failed: -110
>>          spi_master spi0: failed to transfer one message from queue
>>          m25p80 spi0.0: mx25v8035f (1024 Kbytes)
>>          spi_imx 30820000.spi: probed
>>
>> It would be great to get your patches merged and fix SPI + DMA, but for
>> i.MX8MM, we need to get rid of the error messages. Do you have an idea,
>> what's wrong?

> Could you check if the length of spi message is bigger than fifo_size during
> spi_nor probe? If yes, at that time maybe sdma firmware not loaded.
> if (transfer->len < spi_imx->devtype_data->fifo_size)

Indeed, most of the transfers triggered by the SPI NOR dirver are below 
fifo_size and work fine, but some are bigger. The transfers therefore 
try to use DMA, but the firmware is not loaded yet.

How is this supposed to work? Shouldn't all transfers use PIO as long as 
the SDMA firmware is not loaded yet?

(+ Cc: linux-spi@...r.kernel.org)