What are you expecting to happen?
BAR enabled and working with PCI_IO
What is happening that doesn't match that expectation?
It doesn't. PROMISE PDC20265 (pATA chip) fails the PCI_probe
pata_pdc202xx_old 0008:00:04.0: can't enable device: BAR 0 [io size
0x0008] not assigned
pata_pdc202xx_old: probe of 0008:00:04.0 failed with error -22
(kernel 4.11)
I see a lot of things to investigate
Firmware Bug?
invalid BAR (can't size)?
IDE quirk?
Linux is not clear at all
a) Is it a problem with the firmware which doesn't initialize the PCI in the proper way?
b) Is it a problem with the DeviceTree which doesn't pass the correct description (e.g. PCI-range)?
c) Is it a problem with the linux kernel which doesn't support the old PCI_legay stuff?
about c) I can say linux 2.6.22 works on the same board with the same PROMISE PDC20265
PCI: Probing PCI hardware
PCI: Cannot allocate resource region 4 of device 0000:00:04.0
Uniform Multi-Platform E-IDE driver Revision: 7.00alpha2
ide: Assuming 33MHz system bus speed for PIO modes; override with idebus=xx
PDC20265: IDE controller at PCI slot 0000:00:04.0
PDC20265: chipset revision 2
PDC20265: not 100% native mode: will probe irqs later
PDC20265: (U)DMA Burst Bit DISABLED Primary PCI Mode Secondary PCI Mode.
ide0: BM-DMA at 0x1000-0x1007, BIOS settings: hda:DMA, hdb:pio
ide1: BM-DMA at 0x1008-0x100f, BIOS settings: hdc:pio, hdd:pio
(kernel 2.6.22)
lspci
00:04.0 Class 0101: Device 105a:0d30 (rev 02) (prog-if 8a [Master SecP PriP])
Subsystem: Device 105a:4d33
Flags: bus master, medium devsel, latency 128, IRQ 31
I/O ports at 121f0 [size=8]
I/O ports at 123f4 [size=1]
I/O ports at 12170 [size=8]
I/O ports at 12374 [size=1]
I/O ports at 13000 [size=64]
Memory at 81000000 (32-bit, non-prefetchable) [size=128K]
Expansion ROM at <ignored> [disabled]
Capabilities: [58] Power Management version 1
Kernel driver in use: Promise_Old_IDE
(kernel 2.6.22)