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

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

[Daniel Palmer]

The PCI parts are already wrapped in #ifdef CONFIG_PCI
so it seems sensible to add #ifdef CONFIG_ISA around the ISA
parts.

This reduces the code/data size a bit on configs with !CONFIG_ISA.

Signed-off-by: Daniel Palmer <daniel@thingy.jp>
---

Sorry for the spam, somehow I botched sending a patch..

I thought about making this RFC as I'm a bit unsure if machines
that need this ISA stuff actually select CONFIG_ISA or not.

The only in-kernel devicetrees that seem to use this are 4 old powerpc
ones and I couldn't work out if those boards do end up with CONFIG_ISA.

But then again it seems odd for everyone to get this code for 4 old
boards.

 drivers/of/address.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/of/address.c b/drivers/of/address.c
index cf4aab11e9b1..9b2f0d462fb5 100644
--- a/drivers/of/address.c
+++ b/drivers/of/address.c
@@ -277,6 +277,7 @@ int of_range_to_resource(struct device_node *np, int index, struct resource *res
 }
 EXPORT_SYMBOL(of_range_to_resource);
 
+#ifdef CONFIG_ISA
 /*
  * ISA bus specific translator
  */
@@ -316,6 +317,7 @@ static unsigned int of_bus_isa_get_flags(const __be32 *addr)
 		flags |= IORESOURCE_MEM;
 	return flags;
 }
+#endif
 
 static int of_bus_default_flags_match(struct device_node *np)
 {
@@ -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",
@@ -360,6 +363,7 @@ static const struct of_bus of_busses[] = {
 		.flag_cells = 1,
 		.get_flags = of_bus_isa_get_flags,
 	},
+#endif /* CONFIG_ISA */
 	/* Default with flags cell */
 	{
 		.name = "default-flags",
-- 
2.53.0

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

[sashiko-bot]

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`.
--

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