[Upstream] [PATCH v2 1/2] board: phytec: common: Add product information to FTD

[Yannic Moog]

Hello Daniel,

On Wed, 2025-01-15 at 02:35 -0800, Daniel Schultz wrote:
> ft_board_setup inside the board code allows to alter
> device-tree during the boot process.
> 
> Introduce a new function for the PHYTEC SOM detection
> to read the product name and part number from the EEPROM
> content and include both into the device-tree as
> * phytec,som-part-number
> * phytec,som-product-name
> 
> This function can be called from the board code when those
> values should be exposed to Linux.
> 
> Signed-off-by: Daniel Schultz <d.schultz at phytec.de>
> ---
> 
> Changes in v2:
>   * Removed 'struct bd_info' as argument in function phytec_ft_board_fixup
> 
>  board/phytec/common/phytec_som_detection.c | 202 ++++++++++++++++-----
>  board/phytec/common/phytec_som_detection.h |   7 +
>  2 files changed, 166 insertions(+), 43 deletions(-)
> 
> diff --git a/board/phytec/common/phytec_som_detection.c
> b/board/phytec/common/phytec_som_detection.c
> index 166c3eae565..a4a1d20e0ec 100644
> --- a/board/phytec/common/phytec_som_detection.c
> +++ b/board/phytec/common/phytec_som_detection.c
> @@ -271,11 +271,126 @@ err:
>  	return ret;
>  }
>  
> +static int phytec_get_product_name(struct phytec_eeprom_data *data,
> +				   char *product)

phytec_eeprom_data should be const

Please add documentation to this function

> +{
> +	struct phytec_api2_data *api2;
> +	unsigned int ksp_no, som_type;
> +	int len;
> +
> +	if (!data)
> +		data = &eeprom_data;

Why do you have this in here?


> +
> +	if (!data->valid || data->payload.api_rev < PHYTEC_API_REV2)
> +		return -EINVAL;
> +
> +	api2 = &data->payload.data.data_api2;
> +
> +	if (api2->som_type > 1 && api2->som_type <= 3) {
> +		ksp_no = (api2->ksp_no << 8) | api2->som_no;
> +		len = snprintf(product, PHYTEC_PRODUCT_NAME_LEN, "%s-%04u",
> +			       phytec_som_type_str[api2->som_type], ksp_no);
> +		if (len != 8)

Please use a variable here. You used snprintf, so you probably the value you expect here should be
connected to the value you passed to the function.

> +			return -1;

Use error code?

> +		return 0;
> +	}
> +
> +	switch (api2->som_type) {

I think some explanation/documentation on how som_type's value is determined would be useful.

> +	case 0:
> +		som_type = api2->som_type;
> +		break;
> +	case 4:
> +		som_type = 0;
> +		break;
> +	case 5:
> +		som_type = 0;
> +		break;
> +	case 6:
> +		som_type = 1;
> +		break;
> +	case 7:
> +		som_type = 1;
> +		break;
> +	default:
> +		pr_err("%s: Invalid SOM type: %i", __func__, api2->som_type);
> +		return -EINVAL;
> +	};
> +
> +	len = snprintf(product, PHYTEC_PRODUCT_NAME_LEN, "%s-%03u",
> +		       phytec_som_type_str[som_type], api2->som_no);
> +	if (len != 7)
> +		return -1;

Same as above when you called snprintf.


> +	return 0;
> +}
> +
> +static int phytec_get_part_number(struct phytec_eeprom_data *data,
> +				  char  *part)

phytec_eeprom_data should be const

Please add documentation to this function

> +{
> +	char product_name[PHYTEC_PRODUCT_NAME_LEN] = {'\0'};

nitpick: C99 should support  {} as initializer.

> +	struct phytec_api2_data *api2;
> +	unsigned int ksp_type;
> +	int res, len;
> +
> +	if (!data)
> +		data = &eeprom_data;

Why is this here?


> +
> +	if (!data->valid || data->payload.api_rev < PHYTEC_API_REV2)
> +		return -EINVAL;
> +
> +	api2 = &data->payload.data.data_api2;
> +
> +	res = phytec_get_product_name(data, product_name);
> +	if (res)
> +		return res;
> +
> +	if (api2->som_type <= 1) {
> +		len = snprintf(part, PHYTEC_PART_NUMBER_LEN, "%s-%s.%s",
> +			       product_name, api2->opt, api2->bom_rev);
> +		if (len < 11)
> +			return -1;

Please use a variable instead of hardcoded number, see above.

> +		return 0;
> +	}
> +	if (api2->som_type <= 3) {
> +		snprintf(part, PHYTEC_PART_NUMBER_LEN, "%s.%s", product_name,
> +			 api2->bom_rev);
> +		if (len != 11)
> +			return -1;
> +		return 0;
> +	}
> +
> +	switch (api2->som_type) {
> +	case 4:
> +		ksp_type = 3;
> +		break;
> +	case 5:
> +		ksp_type = 2;
> +		break;
> +	case 6:
> +		ksp_type = 3;
> +		break;
> +	case 7:
> +		ksp_type = 2;
> +		break;

Please add some explanation here as well.

> +	default:
> +		pr_err("%s: Invalid SOM type: %i", __func__, api2->som_type);
> +		return -EINVAL;
> +	};
> +
> +	len = snprintf(part, PHYTEC_PART_NUMBER_LEN, "%s-%s%02u.%s",
> +		       product_name, phytec_som_type_str[ksp_type],
> +		       api2->ksp_no, api2->bom_rev);
> +	if (len < 16)
> +		return -1;

Same as for the other cases

> +
> +	return 0;
> +}
> +
>  void __maybe_unused phytec_print_som_info(struct phytec_eeprom_data *data)
>  {
> +	char part_number[PHYTEC_PART_NUMBER_LEN] = {'\0'};
>  	struct phytec_api2_data *api2;
>  	char pcb_sub_rev;
> -	unsigned int ksp_no, sub_som_type1, sub_som_type2;
> +	int res;
>  
>  	if (!data)
>  		data = &eeprom_data;
> @@ -289,50 +404,14 @@ void __maybe_unused phytec_print_som_info(struct phytec_eeprom_data *data)
>  	pcb_sub_rev = api2->pcb_sub_opt_rev & 0x0f;
>  	pcb_sub_rev = pcb_sub_rev ? ((pcb_sub_rev - 1) + 'a') : ' ';
>  
> -	/* print standard product string */
> -	if (api2->som_type <= 1) {
> -		printf("SoM: %s-%03u-%s.%s PCB rev: %u%c\n",
> -		       phytec_som_type_str[api2->som_type], api2->som_no,
> -		       api2->opt, api2->bom_rev, api2->pcb_rev, pcb_sub_rev);
> +	res = phytec_get_part_number(data, part_number);
> +	if (res)
>  		return;
> -	}
> -	/* print KSP/KSM string */
> -	if (api2->som_type <= 3) {
> -		ksp_no = (api2->ksp_no << 8) | api2->som_no;
> -		printf("SoM: %s-%u ",
> -		       phytec_som_type_str[api2->som_type], ksp_no);
> -	/* print standard product based KSP/KSM strings */
> -	} else {
> -		switch (api2->som_type) {
> -		case 4:
> -			sub_som_type1 = 0;
> -			sub_som_type2 = 3;
> -			break;
> -		case 5:
> -			sub_som_type1 = 0;
> -			sub_som_type2 = 2;
> -			break;
> -		case 6:
> -			sub_som_type1 = 1;
> -			sub_som_type2 = 3;
> -			break;
> -		case 7:
> -			sub_som_type1 = 1;
> -			sub_som_type2 = 2;
> -			break;
> -		default:
> -			pr_err("%s: Invalid SoM type: %i", __func__, api2->som_type);
> -			return;
> -		};
> -
> -		printf("SoM: %s-%03u-%s-%03u ",
> -		       phytec_som_type_str[sub_som_type1],
> -		       api2->som_no, phytec_som_type_str[sub_som_type2],
> -		       api2->ksp_no);
> -	}
>  
> -	printf("Option: %s BOM rev: %s PCB rev: %u%c\n", api2->opt,
> -	       api2->bom_rev, api2->pcb_rev, pcb_sub_rev);
> +	printf("SOM: %s\n", part_number);
> +	printf("PCB Rev.: %u%c\n", api2->pcb_rev, pcb_sub_rev);
> +	if (api2->som_type > 1)
> +		printf("Options: %s\n", api2->opt);

You are changing the way infos are printed. Please put this in the commit description! These are
hidden changes.
Otherwise, make a separate patch where you change this.

>  }
>  
>  char * __maybe_unused phytec_get_opt(struct phytec_eeprom_data *data)
> @@ -379,6 +458,37 @@ u8 __maybe_unused phytec_get_som_type(struct phytec_eeprom_data *data)
>  	return data->payload.data.data_api2.som_type;
>  }
>  
> +#if IS_ENABLED(CONFIG_OF_LIBFDT)
> +int phytec_ft_board_fixup(struct phytec_eeprom_data *data, void *blob)
> +{
> +	char product_name[PHYTEC_PRODUCT_NAME_LEN] = {'\0'};
> +	char part_number[PHYTEC_PART_NUMBER_LEN] = {'\0'};
> +	int res;
> +
> +	if (!data)
> +		data = &eeprom_data;
> +
> +	if (!data->valid || data->payload.api_rev < PHYTEC_API_REV2)
> +		return -EINVAL;
> +
> +	res = phytec_get_product_name(data, product_name);
> +	if (res)
> +		return res;
> +
> +	fdt_setprop(blob, 0, "phytec,som-product-name", product_name,
> +		    strlen(product_name) + 1);
> +
> +	res = phytec_get_part_number(data, part_number);
> +	if (res)
> +		return res;
> +
> +	fdt_setprop(blob, 0, "phytec,som-part-number", part_number,
> +		    strlen(part_number) + 1);
> +
> +	return 0;
> +}
> +#endif /* IS_ENABLED(CONFIG_OF_LIBFDT) */
> +
>  #if IS_ENABLED(CONFIG_CMD_EXTENSION)
>  struct extension *phytec_add_extension(const char *name, const char *overlay,
>  				       const char *other)
> @@ -458,6 +568,12 @@ inline struct phytec_api3_element * __maybe_unused
>  	return NULL;
>  }
>  
> +#if IS_ENABLED(CONFIG_OF_LIBFDT)
> +inline int phytec_ft_board_fixup(struct phytec_eeprom_data *data, void *blob)
> +{
> +	return 0;
> +}
> +#endif /* IS_ENABLED(CONFIG_OF_LIBFDT) */
>  #if IS_ENABLED(CONFIG_CMD_EXTENSION)
>  inline struct extension *phytec_add_extension(const char *name,
>  					      const char *overlay,
> diff --git a/board/phytec/common/phytec_som_detection.h
> b/board/phytec/common/phytec_som_detection.h
> index 5e35a13cb21..5b0ff9b0c89 100644
> --- a/board/phytec/common/phytec_som_detection.h
> +++ b/board/phytec/common/phytec_som_detection.h
> @@ -8,6 +8,7 @@
>  #define _PHYTEC_SOM_DETECTION_H
>  
>  #include "phytec_som_detection_blocks.h"
> +#include <fdtdec.h>
>  
>  #define PHYTEC_MAX_OPTIONS	17
>  #define PHYTEC_EEPROM_INVAL	0xff
> @@ -17,6 +18,9 @@
>  #define PHYTEC_GET_OPTION(option) \
>  	(((option) > '9') ? (option) - 'A' + 10 : (option) - '0')
>  
> +#define PHYTEC_PRODUCT_NAME_LEN		8 + 1
> +#define PHYTEC_PART_NUMBER_LEN		PHYTEC_PRODUCT_NAME_LEN + 14 + 1
> +

Do you add 1 here to account for the null byte in the string? 
If so, please do not do that here, instead use PHYTEC_PRODUCT_NAME_LEN +1 in the snprintf function
calls. Also, defining the PHYTEC_PART_NUMBER_LEN based on PHYTEC_PRODUCT_NAME_LEN now becomes
"inconsistent" since you would need to omit the +1 for the null byte you added before.

Yannic

>  enum {
>  	PHYTEC_API_REV0 = 0,
>  	PHYTEC_API_REV1,
> @@ -86,6 +90,9 @@ void __maybe_unused phytec_print_som_info(struct phytec_eeprom_data *data);
>  char * __maybe_unused phytec_get_opt(struct phytec_eeprom_data *data);
>  u8 __maybe_unused phytec_get_rev(struct phytec_eeprom_data *data);
>  u8 __maybe_unused phytec_get_som_type(struct phytec_eeprom_data *data);
> +#if IS_ENABLED(CONFIG_OF_LIBFDT)
> +int phytec_ft_board_fixup(struct phytec_eeprom_data *data, void *blob);
> +#endif /* IS_ENABLED(CONFIG_OF_LIBFDT) */
>  
>  #if IS_ENABLED(CONFIG_CMD_EXTENSION)
>  struct extension *phytec_add_extension(const char *name, const char *overlay,