[PATCH] powerpc: isa-bridge: Fix ISA mmapping when "ranges" is not present

[Christian Zigotzky]

On 05 May 2023 at 07:18 pm, Rob Herring wrote:
> Commit e4ab08be5b49 ("powerpc/isa-bridge: Remove open coded "ranges"
> parsing") broke PASemi Nemo board booting. The issue is the ISA I/O
> range was not getting mapped as the logic to handle no "ranges" was
> inverted. If phb_io_base_phys is non-zero, then the ISA range defaults
> to the first 64K of the PCI I/O space. phb_io_base_phys should only be 0
> when looking for a non-PCI ISA region.
>
> Fixes: e4ab08be5b49 ("powerpc/isa-bridge: Remove open coded "ranges" parsing")
> Link: https://lore.kernel.org/all/301595ad-0edf-2113-b55f-f5b8051ed24c@xenosoft.de/
> Reported-by: Christian Zigotzky <chzigotzky at xenosoft.de>
> Signed-off-by: Rob Herring <robh at kernel.org>
> ---
> Untested, but I think this should fix the issue.
>
>   arch/powerpc/kernel/isa-bridge.c | 5 +++--
>   1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/arch/powerpc/kernel/isa-bridge.c b/arch/powerpc/kernel/isa-bridge.c
> index 85bdd7d3652f..48e0eaf1ad61 100644
> --- a/arch/powerpc/kernel/isa-bridge.c
> +++ b/arch/powerpc/kernel/isa-bridge.c
> @@ -93,11 +93,12 @@ static int process_ISA_OF_ranges(struct device_node *isa_node,
>   	}
>   
>   inval_range:
> -	if (!phb_io_base_phys) {
> +	if (phb_io_base_phys) {
>   		pr_err("no ISA IO ranges or unexpected isa range, mapping 64k\n");
>   		remap_isa_base(phb_io_base_phys, 0x10000);
> +		return 0;
>   	}
> -	return 0;
> +	return -EINVAL;
>   }
>   
>   
The Nemo board boots with this patch. Thanks a lot for your help!

Tested-by: Christian Zigotzky <chzigotzky at xenosoft.de>