Re: [PATCH] of/address: Drop ISA parts when !CONFIG_ISA

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [High] Wrapping the 'isa' OF bus translator in `#ifdef CONFIG_ISA` breaks I/O address translation for LPC/ISA bridges on architectures that do not enable `CONFIG_ISA`.
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commit 2b56de0432a2e0bc839872a80da8947f0a3d2b72
Author: Daniel Palmer <daniel@thingy.jp>

of/address: Drop ISA parts when !CONFIG_ISA

This commit wraps the ISA-specific address translation code in of/address.c
with #ifdef CONFIG_ISA. This is intended to reduce code and data size on
configurations that do not enable CONFIG_ISA.

> diff --git a/drivers/of/address.c b/drivers/of/address.c
> index cf4aab11e9b1f..9b2f0d462fb59 100644
> --- a/drivers/of/address.c
> +++ b/drivers/of/address.c

[ ... ]

> @@ -349,6 +351,7 @@ static const struct of_bus of_busses[] = {
>  		.get_flags = of_bus_pci_get_flags,
>  	},
>  #endif /* CONFIG_PCI */
> +#ifdef CONFIG_ISA
>  	/* ISA */
>  	{
>  		.name = "isa",
>  		.addresses = "reg",
>  		.match = of_bus_isa_match,
>  		.count_cells = of_bus_isa_count_cells,
>  		.map = of_bus_isa_map,
>  		.translate = of_bus_default_flags_translate,
>  		.flag_cells = 1,
>  		.get_flags = of_bus_isa_get_flags,
>  	},
> +#endif /* CONFIG_ISA */

[Severity: High]
Will this break I/O address translation for LPC/ISA bridges on architectures
that do not enable CONFIG_ISA?

While the architecture itself might not have CONFIG_ISA enabled (such as
ARM64, PowerPC, or MIPS), they often still use LPC bridges in their device
trees for devices like RTC, UART, or IPMI nodes. 

If this "isa" translator is completely disabled, the bus mapping will fall
back to the "default" translator. The default translator will incorrectly
parse these resources as IORESOURCE_MEM instead of IORESOURCE_IO.

Could this prevent drivers relying on I/O space access from probing or
mapping resources correctly on those platforms?

>  	/* Default with flags cell */
>  	{
>  		.name = "default-flags",

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260626171906.476688-1-daniel@thingy.jp?part=1