Re: spi: imx: Increase imx51 ecspi burst length fails on imx6dl and imx8mm
From: Linux regression tracking (Thorsten Leemhuis)
Date: Tue Dec 05 2023 - 08:36:41 EST
On 27.11.23 10:09, linux@xxxxxxxxx wrote:
>
> Thank you Benjamin for the patch.
> I have tested the patch and is works fine.
That's great.
Benjamin, what's the status of the fix for this regression? I tried to
find a proper submission for review, but didn't find one. Am I missing
something or did that fall through the cracks?
Ciao, Thorsten (wearing his 'the Linux kernel's regression tracker' hat)
--
Everything you wanna know about Linux kernel regression tracking:
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If I did something stupid, please tell me, as explained on that page.
#regzbot poke
> Am 2023-11-26T14:19:56.000+01:00 hat Benjamin Bigler <benjamin@xxxxxxxxxx> geschrieben:
>> Hi
>>
>> I did some debugging and I think the problem is that in this case bits_per_word is 8. So in
>> spi_imx_dma_configure the buswidth is set to DMA_SLAVE_BUSWIDTH_1_BYTE. But in
>> mx51_ecspi_prepare_transfer the BURST_LENGTH is now set to (spi_imx->count * spi_imx->bits_per_word
>> - 1)
>> before 15a6af94a2779d5dfb42ee4bfac858ea8e964a3f it was (spi_imx->bits_per_word - 1). Now the spi
>> transmits 4 byte per byte except for the first word. I added the following patch and it worked again
>>
>> diff --git a/drivers/spi/spi-imx.c b/drivers/spi/spi-imx.c
>> index 498e35c8db2c..f514966e2ada 100644
>> --- a/drivers/spi/spi-imx.c
>> +++ b/drivers/spi/spi-imx.c
>> @@ -659,11 +659,22 @@ static int mx51_ecspi_prepare_transfer(struct spi_imx_data *spi_imx,
>> ctrl |= (spi_imx->target_burst * 8 - 1)
>> << MX51_ECSPI_CTRL_BL_OFFSET;
>> else {
>> - if (spi_imx->count >= 512)
>> - ctrl |= 0xFFF << MX51_ECSPI_CTRL_BL_OFFSET;
>> - else
>> - ctrl |= (spi_imx->count * spi_imx->bits_per_word - 1)
>> + if (spi_imx->usedma)
>> + ctrl |= (spi_imx->bits_per_word *
>> + spi_imx_bytes_per_word(
>> + spi_imx->bits_per_word) -
>> + 1)
>> << MX51_ECSPI_CTRL_BL_OFFSET;
>> + else {
>> + if (spi_imx->count >= MX51_ECSPI_CTRL_MAX_BURST)
>> + ctrl |= (MX51_ECSPI_CTRL_MAX_BURST - 1)
>> + << MX51_ECSPI_CTRL_BL_OFFSET;
>> + else
>> + ctrl |= (spi_imx->count *
>> + spi_imx->bits_per_word -
>> + 1)
>> + << MX51_ECSPI_CTRL_BL_OFFSET;
>> + }
>> }
>>
>> /* set clock speed */
>>
>> Best regards,
> Benjamin Bigler
>
>