Re: [PATCH 2/2] of/address: Fix WARN when attempting translating non-translatable addresses

[Sean Anderson <sean.anderson@linux.dev>]

On 1/10/25 16:50, Rob Herring (Arm) wrote:
> The recently added WARN() for deprecated #address-cells and #size-cells
> triggered a WARN when of_platform_populate() (which calls
> of_address_to_resource()) is used on nodes with non-translatable
> addresses. This case is expected to return an error.
> 
> Rework the bus matching to allow no match and make the default require
> an #address-cells property. That should be safe to do as any platform
> missing #address-cells would have a warning already.
> 
> Fixes: 045b14ca5c36 ("of: WARN on deprecated #address-cells/#size-cells handling")
> Signed-off-by: Rob Herring (Arm) <robh@kernel.org>
> ---
>  drivers/of/address.c | 18 +++++++++++++++---
>  1 file changed, 15 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/of/address.c b/drivers/of/address.c
> index c1f1c810e810..8770004d9b08 100644
> --- a/drivers/of/address.c
> +++ b/drivers/of/address.c
> @@ -340,6 +340,15 @@ static int of_bus_default_flags_match(struct device_node *np)
>  	return of_property_present(np, "#address-cells") && (of_bus_n_addr_cells(np) == 3);
>  }
>  
> +static int of_bus_default_match(struct device_node *np)
> +{
> +	/*
> +	 * Check for presence first since of_bus_n_addr_cells() will warn when
> +	 * walking parent nodes.
> +	 */
> +	return of_property_present(np, "#address-cells");
> +}
> +
>  /*
>   * Array of bus specific translators
>   */
> @@ -384,7 +393,7 @@ static const struct of_bus of_busses[] = {
>  	{
>  		.name = "default",
>  		.addresses = "reg",
> -		.match = NULL,
> +		.match = of_bus_default_match,
>  		.count_cells = of_bus_default_count_cells,
>  		.map = of_bus_default_map,
>  		.translate = of_bus_default_translate,
> @@ -399,7 +408,6 @@ static const struct of_bus *of_match_bus(struct device_node *np)
>  	for (i = 0; i < ARRAY_SIZE(of_busses); i++)
>  		if (!of_busses[i].match || of_busses[i].match(np))
>  			return &of_busses[i];
> -	BUG();
>  	return NULL;
>  }
>  
> @@ -521,6 +529,8 @@ static u64 __of_translate_address(struct device_node *node,
>  	if (parent == NULL)
>  		return OF_BAD_ADDR;
>  	bus = of_match_bus(parent);
> +	if (!bus)
> +		return OF_BAD_ADDR;
>  
>  	/* Count address cells & copy address locally */
>  	bus->count_cells(dev, &na, &ns);
> @@ -564,6 +574,8 @@ static u64 __of_translate_address(struct device_node *node,
>  
>  		/* Get new parent bus and counts */
>  		pbus = of_match_bus(parent);
> +		if (!pbus)
> +			return OF_BAD_ADDR;
>  		pbus->count_cells(dev, &pna, &pns);
>  		if (!OF_CHECK_COUNTS(pna, pns)) {
>  			pr_err("Bad cell count for %pOF\n", dev);
> @@ -703,7 +715,7 @@ const __be32 *__of_get_address(struct device_node *dev, int index, int bar_no,
>  
>  	/* match the parent's bus type */
>  	bus = of_match_bus(parent);
> -	if (strcmp(bus->name, "pci") && (bar_no >= 0))
> +	if (!bus || (strcmp(bus->name, "pci") && (bar_no >= 0)))
>  		return NULL;
>  
>  	/* Get "reg" or "assigned-addresses" property */

Tested-by: Sean Anderson <sean.anderson@linux.dev>