[RFC PATCH 3/3] serial: mxc: restore booting for imx8mn_bsh_smm_s2

[Michael Nazzareno Trimarchi]

Hi Fabio

On Sat, May 17, 2025 at 9:56 PM Fabio Estevam <festevam at gmail.com> wrote:
>
> Hi Michael,
>
> On Thu, May 15, 2025 at 5:12 PM Michael Nazzareno Trimarchi
> <michael at amarulasolutions.com> wrote:
>
> > The serial is not up at that time so we need to buffer the error and print later. Right now
> > we are working on other fixes
>
> Please share more details about the boot problem on the imx8mn_bsh_smm_s2 board.
>
> Does a hang occur at SPL? Do you get anything in the console?
>
> The mx8mn_bsh_smm_s2 board uses UART4 as the console.
>
> The other i.MX8MN boards where we tested this patch used UART2.
>

Can you please point me to an example of a tested board?

> UART4 does not have U-Boot/Linux permission by default.
>

TF-A is not in the game, the board is working fine.

> TF-A enables the other UART port permission access at:
> https://github.com/ARM-software/arm-trusted-firmware/blob/v2.12/plat/imx/imx8m/imx8mn/imx8mn_bl31_setup.c#L124-L143

I think we have upstream the fix there. Anyway...

>
> Is the UART clock access falling in your case?
>

If the uart is failing you don't have the console

> Is clk_enable_bulk() the one that fails?

I think that something connected to -u-boot.dtsi if you have tested
with some imx8mn

Michael


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Michael Nazzareno Trimarchi
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