Re: [PATCH] ARM: rpi: cleanup parsing of vc fdt

[Ahmad Fatoum <a.fatoum@pengutronix.de>]

On 21.06.22 22:02, Daniel Brát wrote:
> Refactoring and cleanup of vc fdt parsing based on advice
> from Ahmad Fatoum.
> 
> Signed-off-by: Daniel Brát <danek.brat@gmail.com>

Reviewed-by: Ahmad Fatoum <a.fatoum@pengutronix.de>

> ---
> I originally wanted to send these as part of v5 of
> 'ARM: rpi: parse useful data from vc fdt' patch, but you
> were quicker with accepting the v4 :)
> Hope that's not a problem.

Original patch is in next, so this should be squashable.

> 
>  arch/arm/boards/raspberry-pi/rpi-common.c | 114 +++++++++++-----------
>  1 file changed, 58 insertions(+), 56 deletions(-)
> 
> diff --git a/arch/arm/boards/raspberry-pi/rpi-common.c b/arch/arm/boards/raspberry-pi/rpi-common.c
> index eaca4edef..77935e5c8 100644
> --- a/arch/arm/boards/raspberry-pi/rpi-common.c
> +++ b/arch/arm/boards/raspberry-pi/rpi-common.c
> @@ -202,22 +202,52 @@ static int rpi_env_init(void)
>  }
>  
>  /* Some string properties in fdt passed to us from vc may be
> - * malformed by not being null terminated. In that case, create and
> - * return a null terminated copy.
> + * malformed by not being null terminated, so just create and
> + * return a fixed copy.
>   */
>  static char *of_read_vc_string(struct device_node *node,
> -				     const char *prop_name,
> -				     bool *is_dyn)
> +			       const char *prop_name)
>  {
>  	int len;
> -	char *str;
> +	const char *str;
>  
> -	str = (char *)of_get_property(node, prop_name, &len);
> -	if (!str || len <= 0)
> +	str = of_get_property(node, prop_name, &len);
> +	if (!str) {
> +		pr_warn("no property '%s' found in vc fdt's '%s' node\n",
> +			prop_name, node->full_name);
>  		return NULL;
> -	if (is_dyn)
> -		*is_dyn = str[len - 1] != '\0';
> -	return str[len - 1] == '\0' ? str : xstrndup(str, len);
> +	}
> +	return xstrndup(str, len);
> +}
> +
> +static enum reset_src_type rpi_decode_pm_rsts(struct device_node *chosen,
> +					      struct device_node *bootloader)
> +{
> +	u32 pm_rsts;
> +	int ret;
> +
> +	ret = of_property_read_u32(chosen, "pm_rsts", &pm_rsts);
> +	if (ret && bootloader)
> +		 ret = of_property_read_u32(bootloader, "rsts", &pm_rsts);
> +
> +	if (ret) {
> +		pr_warn("'pm_rsts' value not found in vc fdt\n");
> +		return RESET_UKWN;
> +	}
> +	/*
> +	 * https://github.com/raspberrypi/linux/issues/932#issuecomment-93989581
> +	 */
> +
> +	if (pm_rsts & PM_RSTS_HADPOR_SET)
> +		return RESET_POR;
> +	if (pm_rsts & PM_RSTS_HADDR_SET)
> +		return RESET_JTAG;
> +	if (pm_rsts & PM_RSTS_HADWR_SET)
> +		return RESET_WDG;
> +	if (pm_rsts & PM_RSTS_HADSR_SET)
> +		return RESET_RST;
> +
> +	return RESET_UKWN;
>  }
>  
>  static u32 rpi_boot_mode, rpi_boot_part;
> @@ -229,31 +259,22 @@ static void rpi_vc_fdt_parse(void *fdt)
>  {
>  	int ret;
>  	struct device_node *root, *chosen, *bootloader;
> -	enum reset_src_type rst_src = RESET_UKWN;
>  	char *str;
> -	bool is_dyn;
> -	u32 pm_rsts;
>  
>  	root = of_unflatten_dtb(fdt, INT_MAX);
>  	if (IS_ERR(root))
>  		return;
>  
> -	str = of_read_vc_string(root, "serial-number", &is_dyn);
> +	str = of_read_vc_string(root, "serial-number");
>  	if (str) {
>  		barebox_set_serial_number(str);
> -		if (is_dyn)
> -			free(str);
> -	} else {
> -		pr_warn("no 'serial-number' property found in vc fdt root\n");
> +		free(str);
>  	}
>  
> -	str = of_read_vc_string(root, "model", &is_dyn);
> +	str = of_read_vc_string(root, "model");
>  	if (str) {
>  		barebox_set_model(str);
> -		if (is_dyn)
> -			free(str);
> -	} else {
> -		pr_warn("no 'model' property found in vc fdt root\n");
> +		free(str);
>  	}
>  
>  	chosen = of_find_node_by_path_from(root, "/chosen");
> @@ -264,23 +285,23 @@ static void rpi_vc_fdt_parse(void *fdt)
>  
>  	bootloader = of_find_node_by_name(chosen, "bootloader");
>  
> -	str = of_read_vc_string(chosen, "bootargs", NULL);
> -	if (str)
> +	str = of_read_vc_string(chosen, "bootargs");
> +	if (str) {
>  		globalvar_add_simple("vc.bootargs", str);
> -	else
> -		pr_warn("no 'bootargs' property found in vc fdt '/chosen'\n");
> +		free(str);
> +	}
>  
> -	str = of_read_vc_string(chosen, "overlay_prefix", NULL);
> -	if (str)
> +	str = of_read_vc_string(chosen, "overlay_prefix");
> +	if (str) {
>  		globalvar_add_simple("vc.overlay_prefix", str);
> -	else
> -		pr_warn("no 'overlay_prefix' property found in vc fdt '/chosen'\n");
> +		free(str);
> +	}
>  
> -	str = of_read_vc_string(chosen, "os_prefix", NULL);
> -	if (str)
> +	str = of_read_vc_string(chosen, "os_prefix");
> +	if (str) {
>  		globalvar_add_simple("vc.os_prefix", str);
> -	else
> -		pr_warn("no 'os_prefix' property found in vc fdt '/chosen'\n");
> +		free(str);
> +	}
>  
>  	ret = of_property_read_u32(chosen, "boot-mode", &rpi_boot_mode);
>  	if (ret && bootloader)
> @@ -300,28 +321,9 @@ static void rpi_vc_fdt_parse(void *fdt)
>  	else
>  		globalvar_add_simple_int("vc.boot_partition", &rpi_boot_part, "%u");
>  
> -	if (IS_ENABLED(CONFIG_RESET_SOURCE)) {
> -		ret = of_property_read_u32(chosen, "pm_rsts", &pm_rsts);
> -		if (ret && bootloader)
> -			 ret = of_property_read_u32(bootloader, "rsts", &pm_rsts);
> +	if (IS_ENABLED(CONFIG_RESET_SOURCE))
> +		reset_source_set(rpi_decode_pm_rsts(chosen, bootloader));
>  
> -		if (ret) {
> -			pr_warn("pm_rsts could not be get from vc fdt\n");
> -		} else {
> -/*
> - * https://github.com/raspberrypi/linux/issues/932#issuecomment-93989581
> - */
> -			if (pm_rsts & PM_RSTS_HADPOR_SET)
> -				rst_src = RESET_POR;
> -			else if (pm_rsts & PM_RSTS_HADDR_SET)
> -				rst_src = RESET_JTAG;
> -			else if (pm_rsts & PM_RSTS_HADWR_SET)
> -				rst_src = RESET_WDG;
> -			else if (pm_rsts & PM_RSTS_HADSR_SET)
> -				rst_src = RESET_RST;
> -			reset_source_set(rst_src);
> -		}
> -	}
>  out:
>  	if (root)
>  		of_delete_node(root);


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