Re: [PATCH 0/2] MIPS: Loongson2ef: Use pcibios_align_resource() to block io range

["Jiaxun Yang" <jiaxun.yang@flygoat.com>]

On Sat, 31 Jan 2026, at 9:32 PM, Rong Zhang wrote:
> Loongson2ef reserves io range below 0x4000 (LOONGSON_PCI_IO_START) while
> ISA-mode only IDE controller on the south bridge still has a hard
> dependency on ISA IO ports.
>
> The reservation was done by lifting loongson_pci_io_resource.start onto
> 0x4000. Prior to commit ae81aad5c2e1 ("MIPS: PCI: Use
> pci_enable_resources()"), the arch specific pcibios_enable_resources()
> did not check if the resources were claimed, which diverges from what
> PCI core checks, effectively hiding the fact that IDE IO resources were
> not properly within the resource tree. After starting to use
> pcibios_enable_resources() from PCI core, enabling IDE controller fails:
>
>   pata_cs5536 0000:00:0e.2: BAR 0 [io  0x01f0-0x01f7]: not claimed; 
> can't enable device
>   pata_cs5536 0000:00:0e.2: probe with driver pata_cs5536 failed with 
> error -22
>
> MIPS PCI code already has support for enforcing lower bounds using
> PCIBIOS_MIN_IO in pcibios_align_resource() without altering the IO
> window start address itself. Register PCI controller in plat_mem_setup()
> instead of arch_initcall() to make it the root of other resources (e.g.,
> i8259) and prevent resource conflicts. Then, make Loongson2ef PCI code
> use PCIBIOS_MIN_IO too.
>
> Rong Zhang (2):
>   MIPS: Loongson2ef: Register PCI controller in early stage
>   MIPS: Loongson2ef: Use pcibios_align_resource() to block io range

Acked-by: Jiaxun Yang <jiaxun.yang@flygoat.com>

>
>  .../include/asm/mach-loongson2ef/loongson.h    |  6 ++++++
>  arch/mips/loongson2ef/common/pci.c             | 18 +++++++++++-------
>  arch/mips/loongson2ef/common/setup.c           |  1 +
>  3 files changed, 18 insertions(+), 7 deletions(-)
>
>
> base-commit: ad9a728a3388dc5f66eab6b7135e0154249e9403
> -- 
> 2.51.0

-- 
- Jiaxun