SiFive FU740 PCI driver fails on 6.18-rc1

Ron Economos re at w6rz.net
Mon Oct 13 00:14:54 PDT 2025


The SiFive FU740 PCI driver fails on the HiFive Unmatched board with 
Linux 6.18-rc1. The error message is:

[    3.166624] fu740-pcie e00000000.pcie: host bridge 
/soc/pcie at e00000000 ranges:
[    3.166706] fu740-pcie e00000000.pcie:       IO 
0x0060080000..0x006008ffff -> 0x0060080000
[    3.166767] fu740-pcie e00000000.pcie:      MEM 
0x0060090000..0x007fffffff -> 0x0060090000
[    3.166805] fu740-pcie e00000000.pcie:      MEM 
0x2000000000..0x3fffffffff -> 0x2000000000
[    3.166950] fu740-pcie e00000000.pcie: ECAM at [mem 
0xdf0000000-0xdffffffff] for [bus 00-ff]
[    3.579500] fu740-pcie e00000000.pcie: No iATU regions found
[    3.579552] fu740-pcie e00000000.pcie: Failed to configure iATU in 
ECAM mode
[    3.579655] fu740-pcie e00000000.pcie: probe with driver fu740-pcie 
failed with error -22

The normal message (on Linux 6.17.2) is:

[    3.381487] fu740-pcie e00000000.pcie: host bridge 
/soc/pcie at e00000000 ranges:
[    3.381584] fu740-pcie e00000000.pcie:       IO 
0x0060080000..0x006008ffff -> 0x0060080000
[    3.381682] fu740-pcie e00000000.pcie:      MEM 
0x0060090000..0x007fffffff -> 0x0060090000
[    3.381724] fu740-pcie e00000000.pcie:      MEM 
0x2000000000..0x3fffffffff -> 0x2000000000
[    3.484809] fu740-pcie e00000000.pcie: iATU: unroll T, 8 ob, 8 ib, 
align 4K, limit 4096G
[    3.683678] fu740-pcie e00000000.pcie: PCIe Gen.1 x8 link up
[    3.883674] fu740-pcie e00000000.pcie: PCIe Gen.3 x8 link up
[    3.987678] fu740-pcie e00000000.pcie: PCIe Gen.3 x8 link up
[    3.988164] fu740-pcie e00000000.pcie: PCI host bridge to bus 0000:00

Reverting the following commits solves the issue.

0da48c5b2fa731b21bc523c82d927399a1e508b0 PCI: dwc: Support ECAM 
mechanism by enabling iATU 'CFG Shift Feature'

4660e50cf81800f82eeecf743ad1e3e97ab72190 PCI: qcom: Prepare for the DWC 
ECAM enablement

f6fd357f7afbeb34a633e5688a23b9d7eb49d558 PCI: dwc: Prepare the driver 
for enabling ECAM mechanism using iATU 'CFG Shift Feature'




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