Re: [PATCH v3 2/5] remoteproc: imx_rproc: Add support for System Manager API

[Mathieu Poirier <mathieu.poirier@linaro.org>]

Good day,

On Wed, Jun 25, 2025 at 10:23:28AM +0800, Peng Fan (OSS) wrote:
> From: Peng Fan <peng.fan@nxp.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.
> 
> There are three cases for M7:
>  (1) M7 in a separate Logical Machine(LM) that Linux can't control it.
>  (2) M7 in a separate Logical Machine that Linux can control it using
>      LMM protocol
>  (3) M7 runs in same Logical Machine as A55, so Linux can control it
>      using CPU protocol
> 
> So extend the driver to using LMM and CPU protocol to manage the M7 core.
>  - Add IMX_RPROC_SM to indicate the remote core runs on a SoC that
>    has System Manager.
>  - 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 seprate 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.
>

Thanks for the context, it really helps.

 
> 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@nxp.com>
> Signed-off-by: Peng Fan <peng.fan@nxp.com>
> ---
>  drivers/remoteproc/imx_rproc.c | 113 ++++++++++++++++++++++++++++++++++++++++-
>  drivers/remoteproc/imx_rproc.h |   5 ++
>  2 files changed, 116 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/remoteproc/imx_rproc.c b/drivers/remoteproc/imx_rproc.c
> index 74299af1d7f10a0db794de494c52304b2323b89f..b1a117ca5e5795554b67eb7092db2a25fc7de13b 100644
> --- a/drivers/remoteproc/imx_rproc.c
> +++ b/drivers/remoteproc/imx_rproc.c
> @@ -8,6 +8,7 @@
>  #include <linux/clk.h>
>  #include <linux/err.h>
>  #include <linux/firmware/imx/sci.h>
> +#include <linux/firmware/imx/sm.h>
>  #include <linux/interrupt.h>
>  #include <linux/kernel.h>
>  #include <linux/mailbox_client.h>
> @@ -21,6 +22,7 @@
>  #include <linux/reboot.h>
>  #include <linux/regmap.h>
>  #include <linux/remoteproc.h>
> +#include <linux/scmi_imx_protocol.h>
>  #include <linux/workqueue.h>
>  
>  #include "imx_rproc.h"
> @@ -91,6 +93,11 @@ struct imx_rproc_mem {
>  #define ATT_CORE_MASK   0xffff
>  #define ATT_CORE(I)     BIT((I))
>  
> +/* Logical Machine Operation */
> +#define IMX_RPROC_FLAGS_SM_LMM_OP	BIT(0)
> +/* Linux has permission to handle the Logical Machine of remote cores */
> +#define IMX_RPROC_FLAGS_SM_LMM_AVAIL	BIT(1)
> +
>  static int imx_rproc_xtr_mbox_init(struct rproc *rproc, bool tx_block);
>  static void imx_rproc_free_mbox(struct rproc *rproc);
>  
> @@ -115,6 +122,8 @@ struct imx_rproc {
>  	u32				entry;		/* cpu start address */
>  	u32				core_index;
>  	struct dev_pm_domain_list	*pd_list;
> +	/* For i.MX System Manager based systems */
> +	u32				flags;
>  };
>  
>  static const struct imx_rproc_att imx_rproc_att_imx93[] = {
> @@ -393,6 +402,30 @@ static int imx_rproc_start(struct rproc *rproc)
>  	case IMX_RPROC_SCU_API:
>  		ret = imx_sc_pm_cpu_start(priv->ipc_handle, priv->rsrc_id, true, priv->entry);
>  		break;
> +	case IMX_RPROC_SM:
> +		if (priv->flags & IMX_RPROC_FLAGS_SM_LMM_OP) {
> +			if (!(priv->flags & IMX_RPROC_FLAGS_SM_LMM_AVAIL))
> +				return -EACCES;
> +
> +			ret = scmi_imx_lmm_reset_vector_set(dcfg->lmid, dcfg->cpuid, 0, 0);
> +			if (ret) {
> +				dev_err(dev, "Failed to set reset vector lmid(%u), cpuid(%u): %d\n",
> +					dcfg->lmid, dcfg->cpuid, ret);
> +			}
> +
> +			ret = scmi_imx_lmm_operation(dcfg->lmid, SCMI_IMX_LMM_BOOT, 0);
> +			if (ret)
> +				dev_err(dev, "Failed to boot lmm(%d): %d\n", ret, dcfg->lmid);
> +		} else {
> +			ret = scmi_imx_cpu_reset_vector_set(dcfg->cpuid, 0, true, false, false);
> +			if (ret) {
> +				dev_err(dev, "Failed to set reset vector cpuid(%u): %d\n",
> +					dcfg->cpuid, ret);
> +			}
> +
> +			ret = scmi_imx_cpu_start(dcfg->cpuid, true);
> +		}
> +		break;
>  	default:
>  		return -EOPNOTSUPP;
>  	}
> @@ -435,6 +468,16 @@ static int imx_rproc_stop(struct rproc *rproc)
>  	case IMX_RPROC_SCU_API:
>  		ret = imx_sc_pm_cpu_start(priv->ipc_handle, priv->rsrc_id, false, priv->entry);
>  		break;
> +	case IMX_RPROC_SM:
> +		if (priv->flags & IMX_RPROC_FLAGS_SM_LMM_OP) {
> +			if (priv->flags & IMX_RPROC_FLAGS_SM_LMM_AVAIL)
> +				ret = scmi_imx_lmm_operation(dcfg->lmid, SCMI_IMX_LMM_SHUTDOWN, 0);
> +			else
> +				ret = -EACCES;
> +		} else {
> +			ret = scmi_imx_cpu_start(dcfg->cpuid, false);
> +		}
> +		break;
>  	default:
>  		return -EOPNOTSUPP;
>  	}
> @@ -549,9 +592,11 @@ static int imx_rproc_prepare(struct rproc *rproc)
>  {
>  	struct imx_rproc *priv = rproc->priv;
>  	struct device_node *np = priv->dev->of_node;
> +	const struct imx_rproc_dcfg *dcfg = priv->dcfg;
>  	struct of_phandle_iterator it;
>  	struct rproc_mem_entry *mem;
>  	struct reserved_mem *rmem;
> +	int ret;
>  	u32 da;
>  
>  	/* Register associated reserved memory regions */
> @@ -592,6 +637,38 @@ static int imx_rproc_prepare(struct rproc *rproc)
>  		rproc_add_carveout(rproc, mem);
>  	}
>  
> +	switch (dcfg->method) {
> +	case IMX_RPROC_SM:
> +		if (!(priv->flags & IMX_RPROC_FLAGS_SM_LMM_OP))
> +			break;
> +		/*
> +		 * Power on the Logical Machine to make sure TCM is available.
> +		 * Also serve as permission check. If in different Logical
> +		 * Machine, and linux has permission to handle the Logical
> +		 * Machine, set IMX_RPROC_FLAGS_SM_LMM_AVAIL.
> +		 */
> +		ret = scmi_imx_lmm_operation(dcfg->lmid, SCMI_IMX_LMM_POWER_ON, 0);
> +		if (ret == 0) {
> +			dev_info(priv->dev, "lmm(%d) powered on\n", dcfg->lmid);
> +			priv->flags |= IMX_RPROC_FLAGS_SM_LMM_AVAIL;

This is set all the time imx_rproc_prepare() is called - isn't there a way to
set it once at initialisation time?

> +		} else if (ret == -EACCES) {
> +			dev_info(priv->dev, "lmm(%d) not under Linux Control\n", dcfg->lmid);
> +			/*
> +			 * If remote cores boots up in detached mode, continue;
> +			 * else linux has no permission, return -EACCES.
> +			 */
> +			if (priv->rproc->state != RPROC_DETACHED)
> +				return -EACCES;
> +		} else if (ret) {
> +			dev_err(priv->dev, "Failed to power on lmm(%d): %d\n", ret, dcfg->lmid);
> +			return ret;
> +		}
> +
> +		break;
> +	default:
> +		break;
> +	};
> +

Please put this in a function and get rid of the switch{}.

>  	return  0;
>  }
>  
> @@ -911,13 +988,41 @@ static int imx_rproc_detect_mode(struct imx_rproc *priv)
>  	struct regmap_config config = { .name = "imx-rproc" };
>  	const struct imx_rproc_dcfg *dcfg = priv->dcfg;
>  	struct device *dev = priv->dev;
> +	struct scmi_imx_lmm_info info;
>  	struct regmap *regmap;
>  	struct arm_smccc_res res;
> +	bool started = false;
>  	int ret;
>  	u32 val;
>  	u8 pt;
>  
>  	switch (dcfg->method) {
> +	case IMX_RPROC_SM:
> +		/* Get current Linux Logical Machine ID */
> +		ret = scmi_imx_lmm_info(LMM_ID_DISCOVER, &info);
> +		if (ret) {
> +			dev_err(dev, "Failed to get current LMM ID err: %d\n", ret);
> +			return ret;
> +		}
> +
> +		/*
> +		 * Check whether remote processor is in same Logical Machine as Linux.
> +		 * If no, need use Logical Machine API to manage remote processor, and
> +		 * set IMX_RPROC_FLAGS_SM_LMM_OP.
> +		 * If yes, use CPU protocol API to manage remote processor.
> +		 */
> +		if (dcfg->lmid != info.lmid) {
> +			priv->flags |= IMX_RPROC_FLAGS_SM_LMM_OP;
> +			dev_info(dev, "Using LMM Protocol OPS\n");
> +		} else {
> +			dev_info(dev, "Using CPU Protocol OPS\n");
> +		}
> +
> +		scmi_imx_cpu_started(dcfg->cpuid, &started);

Function scmi_imx_cpu_started() returns a value that is not taken into account.

> +		if (started)
> +			priv->rproc->state = RPROC_DETACHED;
> +
> +		return 0;
>  	case IMX_RPROC_NONE:
>  		priv->rproc->state = RPROC_DETACHED;
>  		return 0;
> @@ -1029,8 +1134,12 @@ static int imx_rproc_clk_enable(struct imx_rproc *priv)
>  	struct device *dev = priv->dev;
>  	int ret;
>  
> -	/* Remote core is not under control of Linux */
> -	if (dcfg->method == IMX_RPROC_NONE)
> +	/*
> +	 * IMX_RPROC_NONE indicates not under control of Linux.
> +	 * System Manager(SM) firmware automatically configures clock,
> +	 * so bypass the clk settings for IMX_RPROC_SM.
> +	 */
> +	if (dcfg->method == IMX_RPROC_NONE || dcfg->method == IMX_RPROC_SM)
>  		return 0;
>  
>  	priv->clk = devm_clk_get(dev, NULL);
> diff --git a/drivers/remoteproc/imx_rproc.h b/drivers/remoteproc/imx_rproc.h
> index cfd38d37e1467d1d9e6f89be146c0b53262b92a0..6fe8d975ed302967f27b7a4319a899e6f0822976 100644
> --- a/drivers/remoteproc/imx_rproc.h
> +++ b/drivers/remoteproc/imx_rproc.h
> @@ -26,6 +26,8 @@ enum imx_rproc_method {
>  	IMX_RPROC_SCU_API,
>  	/* Through Reset Controller API */
>  	IMX_RPROC_RESET_CONTROLLER,
> +	/* Through System Manager */
> +	IMX_RPROC_SM,
>  };
>  
>  /* dcfg flags */
> @@ -42,6 +44,9 @@ struct imx_rproc_dcfg {
>  	size_t				att_size;
>  	enum imx_rproc_method		method;
>  	u32				flags;
> +	/* For System Manager(SM) based SoCs, the IDs are from SM firmware */
> +	u32				cpuid;
> +	u32				lmid;
>  };
>  
>  #endif /* _IMX_RPROC_H */
> 
> -- 
> 2.37.1
>