wifi: ath12k: start-up crash with WCN7850 hw2.0 on TI AM69-SK board

[Baochen Qiang]

On 5/15/2025 10:23 PM, Francesco Dolcini wrote:
> Hello,
> 
> On Tue, May 06, 2025 at 01:56:11PM +0800, Baochen Qiang wrote:
>> On 4/30/2025 8:50 PM, Parth Panchoil wrote:
>>> On Wed, 2025-02-19 at 18:18 +0800, Baochen Qiang wrote:
>>>> On 2/5/2025 10:20 AM, Baochen Qiang wrote:
>>>>> On 1/27/2025 10:01 PM, Parth Panchoil wrote:
>>>>>> I am currently debugging the ath12k_pci_enable_ltssm start up
>>>>>> crash/bug
>>>>>> with the mainline kernel on my system and would like to share my
>>>>>> observations so far:
>>>>>>
>>>>>> The ath12k mainline driver gets stuck at this specific line: 
>>>>>> https://github.com/torvalds/linux/blob/9c5968db9e625019a0ee5226c7eebef5519d366a/drivers/net/wireless/ath/ath12k/pci.c#L295
>>>>>> in the ath12k_pci_enable_ltssm  which attempts to read
>>>>>> GCC_GCC_PCIE_HOT_RST, particularly
>>>>>> https://github.com/torvalds/linux/blob/9c5968db9e625019a0ee5226c7eebef5519d366a/drivers/net/wireless/ath/ath12k/pci.c#L1209
> 
> ...
> 
>>>>
>>>> -#define GCC_GCC_PCIE_HOT_RST                   0x1e38338
>>>> +#define GCC_GCC_PCIE_HOT_RST                   0x1e40304
> 
> ...
> 
>>
>> GCC_GCC_PCIE_HOT_RST is wrongly defined, normally this should not cause any critical
>> issue, because IMO the RC is expected to return 0xffffffff when accessing a non-exist
>> register. However in your case kernel crashes, so seems RC does not behave well, maybe not
>> following spec?
>>
>> anyway I will submit a patch to fix it.
> 
> Any update on this? I can easily submit a patch myself, just let me
> know. Because of this bug we have a crash that is preventing us to use
> the device.
> 

The patch has been submitted for internal review. Will make it public available once
approved internally.

> Francesco
>