Re: SiFive FU740 PCI driver fails on 6.18-rc1

[Krishna Chaitanya Chundru <krishna.chundru@oss.qualcomm.com>]

On 10/14/2025 10:56 AM, Ron Economos wrote:
> On 10/13/25 22:20, Krishna Chaitanya Chundru wrote:
>>
>>
>> On 10/14/2025 2:58 AM, Bjorn Helgaas wrote:
>>> [+cc FU740 driver folks, Conor, regressions]
>>>
>>> On Mon, Oct 13, 2025 at 12:14:54AM -0700, Ron Economos wrote:
>>>> 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@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@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'
>>>
>>> As Conor pointed out, we can't fix a code regression with a DT change.
>>>
>>> #regzbot introduced: f6fd357f7afb ("PCI: dwc: Prepare the driver for 
>>> enabling ECAM mechanism using iATU 'CFG Shift Feature'")
>> Hi Conor,
>>
>> Can you try with this patch and see if it is fixing the issue.
>> diff --git a/drivers/pci/controller/dwc/pcie-fu740.c 
>> b/drivers/pci/controller/dwc/pcie-fu740.c
>> index 66367252032b..b5e0f016a580 100644
>> --- a/drivers/pci/controller/dwc/pcie-fu740.c
>> +++ b/drivers/pci/controller/dwc/pcie-fu740.c
>> @@ -328,6 +328,8 @@ static int fu740_pcie_probe(struct platform_device 
>> *pdev)
>>
>>         platform_set_drvdata(pdev, afp);
>>
>> +       pci->pp.native_ecam = true;
>> +
>>         return dw_pcie_host_init(&pci->pp);
>>  }
>>
>> - Krishna Chaitanya.
>>
>>>
> I've already tried it. It doesn't work. Same error message as before.
Can you share us dmesg logs for this change.

- Krishna Chaitanya.
>