[U-Boot] FSL PCIe LTSSM >= PCI_LTSSM_L0 equals link up

[York Sun]

On 09/05/2017 04:08 AM, Joakim Tjernlund wrote:
> On Mon, 2017-08-28 at 17:14 +0000, York Sun wrote:
>> +Xiaowei
>>
>> On 08/28/2017 10:09 AM, Joakim Tjernlund wrote:
>>> On Mon, 2017-08-28 at 16:55 +0000, York Sun wrote:
>>>> On 08/28/2017 09:48 AM, Joakim Tjernlund wrote:
>>>>> FSL PCIe controller drivers before REV 3 has this test for link up:
>>>>>      enabled = ltssm >= PCI_LTSSM_L0;
>>>>>
>>>>> We have a PCIe dev. that stays in LTSSM=0x51 (Polling Compliance) when non ready
>>>>> for PCI transaktions. When FSL PCIe controller tries to access this device, it
>>>>> hangs forever.
>>>>>
>>>>> Is LTSSM=0x51 really a "legal" state for link up?
>>>>> If not, what is a suitable range(maybe LO <= ltssm <= L0s(0x27)) ?
>>>>>
>>>>>     Jocke
>>>>>
>>>>> BTW, the same test is valid in Linux too.
>>>>>
>>>>
>>>> Jocke,
>>>>
>>>> I am not an expert on PCIe. Please if this thread is helpful,
>>>
>>> Me neither .. :)
>>>>    
>>>> https://emea01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fpatchwork.ozlabs.org%2Fpatch%2F801519%2F&data=01%7C01%7Cyork.sun%40nxp.com%7Cf46ff5111ba04e631a9b08d4ee377ecc%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0&sdata=n9%2B2NIjEvsMBCljRLHS6NVVN4ANa3nBGpwUjI4Od%2Bhs%3D&reserved=0.
>>>
>>> It mentions polling compliance but this driver already tests for:
>>> if (ltssm < LTSSM_PCIE_L0)
>>> 		return 0;
>>> 	return 1;
>>>
>>> It just adds some delay if the device is in Polling Compliance to see if that
>>> changes to L0.
>>> Since both layerscape and fsl >= rev 3 already require ltssm to be == L0, I suspect
>>> the ltssm >= L0 is bogus.
>>>
>>
>> Xiaowei, can you comment?
>>
>> York
> 
> Ping?
> Should I just send a patch ?
> 

+Mingkai