Re: [PATCH v3 4/8] thermal: amlogic: Add support for secure monitor calibration readout

[Daniel Lezcano <daniel.lezcano@oss.qualcomm.com>]

Hi Ronald,

On 4/21/26 09:19, Ronald Claveau wrote:
> Some SoCs (e.g. T7) expose thermal calibration data through the secure
> monitor rather than a directly accessible eFuse register. Add a use_sm
> flag to amlogic_thermal_data to select this path, and retrieve the
> firmware handle and tsensor_id from the "amlogic,secure-monitor" DT
> phandle with one fixed argument.
> 
> Also introduce the amlogic,t7-thermal compatible using this new path.
> 
> Signed-off-by: Ronald Claveau <linux-kernel-dev@aliel.fr>
> ---
>   drivers/thermal/amlogic_thermal.c | 58 +++++++++++++++++++++++++++++++++++----
>   1 file changed, 53 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/thermal/amlogic_thermal.c b/drivers/thermal/amlogic_thermal.c
> index 5448d772db12a..11e3948cc0669 100644
> --- a/drivers/thermal/amlogic_thermal.c
> +++ b/drivers/thermal/amlogic_thermal.c
> @@ -25,6 +25,7 @@
>   #include <linux/platform_device.h>
>   #include <linux/regmap.h>
>   #include <linux/thermal.h>
> +#include <linux/firmware/meson/meson_sm.h>
>   
>   #include "thermal_hwmon.h"
>   
> @@ -84,12 +85,14 @@ struct amlogic_thermal_soc_calib_data {
>    * @u_efuse_off: register offset to read fused calibration value
>    * @calibration_parameters: calibration parameters structure pointer
>    * @regmap_config: regmap config for the device
> + * @use_sm: read data from secure monitor instead of efuse
>    * This structure is required for configuration of amlogic thermal driver.
>    */
>   struct amlogic_thermal_data {
>   	int u_efuse_off;
>   	const struct amlogic_thermal_soc_calib_data *calibration_parameters;
>   	const struct regmap_config *regmap_config;
> +	bool use_sm;
>   };
>   
>   struct amlogic_thermal {
> @@ -100,6 +103,8 @@ struct amlogic_thermal {
>   	struct clk *clk;
>   	struct thermal_zone_device *tzd;
>   	u32 trim_info;
> +	struct meson_sm_firmware *sm_fw;
> +	u32 tsensor_id;
>   };
>   
>   /*
> @@ -138,6 +143,12 @@ static int amlogic_thermal_initialize(struct amlogic_thermal *pdata)
>   	int ret = 0;
>   	int ver;
>   
> +	if (pdata->data->use_sm) {
> +		return meson_sm_get_thermal_calib(pdata->sm_fw,
> +						  &pdata->trim_info,
> +						  pdata->tsensor_id);
> +	}
> +
>   	regmap_read(pdata->sec_ao_map, pdata->data->u_efuse_off,
>   		    &pdata->trim_info);
>   
> @@ -226,6 +237,12 @@ static const struct amlogic_thermal_data amlogic_thermal_a1_cpu_param = {
>   	.regmap_config = &amlogic_thermal_regmap_config_g12a,
>   };
>   
> +static const struct amlogic_thermal_data amlogic_thermal_t7_param = {
> +	.use_sm			= true,
> +	.calibration_parameters	= &amlogic_thermal_g12a,
> +	.regmap_config		= &amlogic_thermal_regmap_config_g12a,
> +};
> +
>   static const struct of_device_id of_amlogic_thermal_match[] = {
>   	{
>   		.compatible = "amlogic,g12a-ddr-thermal",
> @@ -239,6 +256,10 @@ static const struct of_device_id of_amlogic_thermal_match[] = {
>   		.compatible = "amlogic,a1-cpu-thermal",
>   		.data = &amlogic_thermal_a1_cpu_param,
>   	},
> +	{
> +		.compatible = "amlogic,t7-thermal",
> +		.data = &amlogic_thermal_t7_param,
> +	},
>   	{ /* sentinel */ }
>   };
>   MODULE_DEVICE_TABLE(of, of_amlogic_thermal_match);
> @@ -271,11 +292,38 @@ static int amlogic_thermal_probe(struct platform_device *pdev)
>   	if (IS_ERR(pdata->clk))
>   		return dev_err_probe(dev, PTR_ERR(pdata->clk), "failed to get clock\n");
>   
> -	pdata->sec_ao_map = syscon_regmap_lookup_by_phandle
> -		(pdev->dev.of_node, "amlogic,ao-secure");
> -	if (IS_ERR(pdata->sec_ao_map)) {
> -		dev_err(dev, "syscon regmap lookup failed.\n");
> -		return PTR_ERR(pdata->sec_ao_map);
> +	if (pdata->data->use_sm) {
> +		struct device_node *sm_np;
> +		struct of_phandle_args ph_args;
> +
> +		ret = of_parse_phandle_with_fixed_args(pdev->dev.of_node,
> +						       "amlogic,secure-monitor",
> +						       1, 0, &ph_args);
> +		if (ret)
> +			return ret;
> +
> +		sm_np = ph_args.np;
> +		if (!sm_np) {
> +			dev_err(dev,
> +				"Failed to parse secure monitor phandle\n");
> +			return -ENODEV;
> +		}
> +
> +		pdata->sm_fw = meson_sm_get(sm_np);
> +		of_node_put(sm_np);
> +		if (!pdata->sm_fw) {
> +			dev_err(dev, "Failed to get secure monitor firmware\n");
> +			return -EPROBE_DEFER;
> +		}
> +
> +		pdata->tsensor_id = ph_args.args[0];
> +	} else {
> +		pdata->sec_ao_map = syscon_regmap_lookup_by_phandle
> +			(pdev->dev.of_node, "amlogic,ao-secure");
> +		if (IS_ERR(pdata->sec_ao_map)) {
> +			dev_err(dev, "syscon regmap lookup failed.\n");
> +			return PTR_ERR(pdata->sec_ao_map);
> +		}
>   	}

I suggest to separate these two routines into functions. That will help 
the readability.

>   	pdata->tzd = devm_thermal_of_zone_register(&pdev->dev

The thermal zone is registered before calling 
amlogic_thermal_initialize(), thus pdata->trim_info is not initialized. 
When a thermal zone is registered the thermal framework reads the 
temperature, so it reads an invalid value because:

devm_thermal_of_zone_register()
  -> thermal_of_zone_register()
    -> thermal_zone_device_register_with_trips()
    -> thermal_zone_device_enable()
       -> __thermal_zone_device_update()
         -> __thermal_zone_get_temp()
           -> amlogic_thermal_get_temp()
              -> amlogic_thermal_code_to_millicelsius()
                  [ Use of uninitialized pdata->trim_info ]

Right ?

IIUC, amlogic_thermal_initialize() can be also split and moved the 
corresponding blocks to the functions to be created in the comment above.


>