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Message-ID: <89209fbb46c4ce650141ecb6fdf06476@mail.infomaniak.com>
Date:   Mon, 27 Nov 2023 10:09:27 +0100
Subject: Re: spi: imx: Increase imx51 ecspi burst length fails on imx6dl and
 imx8mm
From:   linux@bigler.io
Reply-To: linux@bigler.io
To:     Benjamin Bigler <benjamin@bigler.one>
Cc:     broonie@kernel.org, francesco@dolcini.it,
        linux-kernel@vger.kernel.org, linux-spi@vger.kernel.org,
        regressions@lists.linux.dev, stefan.moring@technolution.nl
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References: <c7a38307ac74a973e26ac820a0b98773262720bd.camel@bigler.one>
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Hi=20

Thank you Benjamin for the patch.
I have tested the patch and is works fine.

Best regards
Stefan Bigler

Am 2023-11-26T14:19:56.000+01:00 hat Benjamin Bigler <benjamin@bigler.one> =
geschrieben:
>  Hi
>=20
> I did some debugging and I think the problem is that in this case bits_pe=
r_word is 8. So in
> spi_imx_dma_configure the buswidth is set to DMA_SLAVE_BUSWIDTH_1_BYTE. B=
ut in
> mx51_ecspi_prepare_transfer the BURST_LENGTH is now set to (spi_imx->coun=
t * 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 followin=
g patch and it worked again
>=20
> 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_i=
mx_data *spi_imx,
>  =09=09ctrl |=3D (spi_imx->target_burst * 8 - 1)
>  =09=09=09<< MX51_ECSPI_CTRL_BL_OFFSET;
>  =09else {
> -=09=09if (spi_imx->count &gt;=3D 512)
> -=09=09=09ctrl |=3D 0xFFF << MX51_ECSPI_CTRL_BL_OFFSET;
> -=09=09else
> -=09=09=09ctrl |=3D (spi_imx->count * spi_imx->bits_per_word - 1)
> +=09=09if (spi_imx->usedma)
> +=09=09=09ctrl |=3D (spi_imx->bits_per_word *
> +=09=09=09=09=09 spi_imx_bytes_per_word(
> +=09=09=09=09=09=09 spi_imx->bits_per_word) -
> +=09=09=09=09 1)
>  =09=09=09=09<< MX51_ECSPI_CTRL_BL_OFFSET;
> +=09=09else {
> +=09=09=09if (spi_imx->count &gt;=3D MX51_ECSPI_CTRL_MAX_BURST)
> +=09=09=09=09ctrl |=3D (MX51_ECSPI_CTRL_MAX_BURST - 1)
> +=09=09=09=09=09<< MX51_ECSPI_CTRL_BL_OFFSET;
> +=09=09=09else
> +=09=09=09=09ctrl |=3D (spi_imx->count *
> +=09=09=09=09=09=09 spi_imx->bits_per_word -
> +=09=09=09=09=09 1)
> +=09=09=09=09=09<< MX51_ECSPI_CTRL_BL_OFFSET;
> +=09=09}
>  =09}
> =20
>  =09/* set clock speed */
>=20
> Best regards,
Benjamin Bigler