On Tue, Dec 16, 2025 at 3:53 AM Peng Fan (OSS) <[email protected]> wrote: > > From: Peng Fan <[email protected]> > > 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 <[email protected]>
Reviewed-by: Daniel Baluta <[email protected]>
