Re: [PATCH v6 4/6] remoteproc: imx_rproc: Add support for System Manager LMM API

[Daniel Baluta]

On Fri, Jan 9, 2026 at 2:11 PM Peng Fan (OSS) <peng.fan@xxxxxxxxxxx> wrote:
>
> From: Peng Fan <peng.fan@xxxxxxx>
>
> i.MX95 features a Cortex-M33 core, six Cortex-A55 cores, and
> one Cortex-M7 core. The System Control Management Interface(SCMI)
> firmware runs on the M33 core. The i.MX95 SCMI firmware named System
> Manager(SM) includes vendor extension protocols, Logical Machine
> Management(LMM) protocol and CPU protocol and etc.
>
> Depending on SM configuration, M7 can be used as follows:
>  (1) M7 in a separate Logical Machine (LM) from A55 cores, that Linux
>      can't control
>  (2) M7 in a separate LM from A55 cores that Linux can control using LMM
>      protocol.
>  (3) M7 runs in same Logical Machine as A55 cores, so Linux can control it
>      using CPU protocol
>
> So extend the driver to using LMM and CPU protocol to manage the M7 core.
>  - Compare linux LM ID(got using scmi_imx_lmm_info) and M7 LM ID(the ID
>    is fixed as 1 in SM firmware if M7 is in a separate LM),
>    if Linux LM ID is not same as M7 LM ID(linux and M7 in same LM), use
>    LMM protocol to start/stop. CPU protocol support will be added in the
>    following patch. Whether using CPU or LMM protocol to start/stop, the
>    M7 status detection could use CPU protocol to detect started or not. So
>    in imx_rproc_detect_mode, use scmi_imx_cpu_started to check the
>    status of M7.
>  - For above case (1) and (2), Use SCMI_IMX_LMM_POWER_ON to detect whether
>    the M7 LM is under control of A55 LM.
>  - For above case , after using SCMI_IMX_LMM_POWER_ON to check
>    permission, SCMI_IMX_LMM_SHUTDOWN API should be called to shutdown
>    the M7 LM to save power only when M7 LM is going to be started by
>    remoteproc framework. Otherwise bypass SCMI_IMX_LMM_SHUTDOWN API if
>    M7 LM is started before booting Linux.
>
> Current setup relies on pre-Linux software(U-Boot) to do M7 TCM ECC
> initialization. In future, we could add the support in Linux to decouple
> U-Boot and Linux.
>
> Reviewed-by: Daniel Baluta <daniel.baluta@xxxxxxx>
> Reviewed-by: Frank Li <Frank.Li@xxxxxxx>
> Signed-off-by: Peng Fan <peng.fan@xxxxxxx>

Ok, for my R-b tag but in this case of re-writing the code in the
future please remove the tag
as new reviews needs to be done.

The code is OK although it needs a bit of a time to understand it. The
commit message should
only point important stuff - that cannot be understood from the code easily.

Overall, I'm fine with this. I think it is in a mergeable form.