On Mon, Nov 24, 2025 at 12:28:00PM -0500, Frank Li wrote:
>On Sat, Nov 22, 2025 at 08:58:19AM +0800, Peng Fan (OSS) 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]>
>> ---
>> drivers/remoteproc/Kconfig | 2 +
>> drivers/remoteproc/imx_rproc.c | 193
>> +++++++++++++++++++++++++++++++++++++++++
>> drivers/remoteproc/imx_rproc.h | 3 +
>> 3 files changed, 198 insertions(+)
>>
>...
>> +
>> +static int imx_rproc_sm_lmm_check(struct rproc *rproc, bool started)
>> +{
>> + struct imx_rproc *priv = rproc->priv;
>> + const struct imx_rproc_dcfg *dcfg = priv->dcfg;
>> + struct device *dev = priv->dev;
>> + int ret;
>> +
>> + /*
>> + * Use power on to do permission check. If rproc is in different LM,
>> + * and linux has permission to handle the LM, set
>> IMX_RPROC_FLAGS_SM_LMM_AVAIL.
>> + */
>> + ret = scmi_imx_lmm_operation(dcfg->lmid, SCMI_IMX_LMM_POWER_ON, 0);
>> + if (ret != 0) {
>
>if (ret)
Fix in next version.
>
>> + if (ret == -EACCES) {
>> + /*
>> + * rproc LM is booted before Linux and not under Linux
>> Control, so only
>> + * do IPC between RPROC and Linux, not return failure
>> + */
>> + dev_info(dev, "lmm(%d) not under Linux Control\n",
>> dcfg->lmid);
>> + return 0;
>> + }
>> +
>> + dev_err(dev, "power on lmm(%d) failed: %d\n", dcfg->lmid, ret);
>> + return ret;
>> + }
>> +
>> + priv->flags |= IMX_RPROC_FLAGS_SM_LMM_AVAIL;
>> +
>> + /* rproc was started before boot Linux and under control of Linux,
>> directly return */
>> + if (started)
>> + return 0;
>
>should it be before scmi_imx_lmm_operation()? If started, supposed need
>check scmi_imx_lmm_operation()?
No. We need to detect whether M7 is under control of Linux before return.
Thanks,
Peng
>
>Frank
>> +
>> + /* else shutdown the LM to save power */
>> + ret = scmi_imx_lmm_operation(dcfg->lmid, SCMI_IMX_LMM_SHUTDOWN, 0);
>> + if (ret) {
>> + priv->flags &= ~IMX_RPROC_FLAGS_SM_LMM_AVAIL;
>> + dev_err(dev, "shutdown lmm(%d) failed: %d\n", dcfg->lmid, ret);
>> + return ret;
>> + }
>> +
>> + return 0;
>> +}
>> +
>...
>> };
>>
>> #endif /* _IMX_RPROC_H */
>>
>> --
>> 2.37.1
>>
