linux-kernel - Re: [PATCH v4 4/5] remoteproc: imx_rproc: Add support for System Manager API

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Message-ID: <CAEnQRZBS7zzc9AmTymCGVKwExeZ-JNFiG9MamWOZmk=gXdBY7w@mail.gmail.com>
Date: Tue, 16 Dec 2025 13:51:55 +0200
From: Daniel Baluta <daniel.baluta@...il.com>
To: "Peng Fan (OSS)" <peng.fan@....nxp.com>
Cc: Bjorn Andersson <andersson@...nel.org>, Mathieu Poirier <mathieu.poirier@...aro.org>, 
	Rob Herring <robh@...nel.org>, Krzysztof Kozlowski <krzk+dt@...nel.org>, Conor Dooley <conor+dt@...nel.org>, 
	Shawn Guo <shawnguo@...nel.org>, Sascha Hauer <s.hauer@...gutronix.de>, 
	Pengutronix Kernel Team <kernel@...gutronix.de>, Fabio Estevam <festevam@...il.com>, Frank Li <Frank.Li@....com>, 
	Daniel Baluta <daniel.baluta@....com>, linux-remoteproc@...r.kernel.org, 
	devicetree@...r.kernel.org, imx@...ts.linux.dev, 
	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org, 
	Peng Fan <peng.fan@....com>
Subject: Re: [PATCH v4 4/5] remoteproc: imx_rproc: Add support for System
 Manager API

On Tue, Dec 16, 2025 at 3:53 AM Peng Fan (OSS) <peng.fan@....nxp.com> wrote:
>
> From: Peng Fan <peng.fan@....com>
>
> 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 equals M7 LM ID(linux and M7 in same LM), use CPU
>    protocol to start/stop. Otherwise, use LMM protocol to start/stop.
>    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.
>
> Signed-off-by: Peng Fan <peng.fan@....com>

Reviewed-by: Daniel Baluta <daniel.baluta@....com>