According to Maciej W. Rozycki <macro@orcam.me.uk>, the
mips_pcibios_init() for malta adjusts root bus IO resource start
address to prevent interfering with PIIX4 I/O cycle decoding. Adjusting
lower bound leaves PIIX4 IO resources outside of the root bus resource
and assign_fixed_resource_on_bus() does not link the resources into the
resource tree.
Prior to commit ae81aad5c2 ("MIPS: PCI: Use pci_enable_resources()") the
arch specific pcibios_enable_resources() did not check if the resources
were assigned which diverges from what PCI core checks, effectively hiding
the PIIX4 IO resources were not properly within the resource tree. After
starting to use pcibios_enable_resources() from PCI core, enabling PIIX4
fails:
ata_piix 0000:00:0a.1: BAR 0 [io 0x01f0-0x01f7]: not claimed; can't enable device
ata_piix 0000:00:0a.1: probe with driver ata_piix 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. Make malta PCI code too to use PCIBIOS_MIN_IO.
Fixes: ae81aad5c2 ("MIPS: PCI: Use pci_enable_resources()")
Reported-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/linux-pci/9085ab12-1559-4462-9b18-f03dcb9a4088@roeck-us.net/
Suggested-by: Maciej W. Rozycki <macro@orcam.me.uk>
Link: https://lore.kernel.org/linux-pci/alpine.DEB.2.21.2510132229120.39634@angie.orcam.me.uk/
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Tested-by: Maciej W. Rozycki <macro@orcam.me.uk>
Acked-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Link: https://patch.msgid.link/20251017110903.1973-1-ilpo.jarvinen@linux.intel.com
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