Re: [PATCH v4 5/6] PCI: qcom: Add support for X1E80100 SoC

Qiang Yu
2024-09-26T03:29:16Z

On 9/25/2024 4:07 PM, Manivannan Sadhasivam wrote:
> On Wed, Sep 25, 2024 at 11:47:02AM +0800, Qiang Yu wrote:
>> On 9/24/2024 11:17 PM, Johan Hovold wrote:
>>> On Tue, Sep 24, 2024 at 03:50:21PM +0200, Manivannan Sadhasivam wrote:
>>>> On Tue, Sep 24, 2024 at 03:14:43AM -0700, Qiang Yu wrote:
>>>>> X1E80100 has PCIe ports that support up to Gen4 x8 based on hardware IP
>>>>> version 1.38.0.
>>>>>
>>>>> Currently the ops_1_9_0 which is being used for X1E80100 has config_sid
>>>>> callback to config BDF to SID table. However, this callback is not
>>>>> required for X1E80100 because it has smmuv3 support and BDF to SID table
>>>>> will be not present.
>>>>>
>>>>> Hence add support for X1E80100 by introducing a new ops and cfg structures
>>>>> that don't require the config_sid callback. This could be reused by the
>>>>> future platforms based on SMMUv3.
>>>>>
>>>> Oops... I completely overlooked that you are not adding the SoC support but
>>>> fixing the existing one :( Sorry for suggesting a commit message that changed
>>>> the context.
>>>>
>>>> For this, you can have something like:
>>>>
>>>> "PCI: qcom: Fix the ops for X1E80100 SoC
>>>>
>>>> X1E80100 SoC is based on SMMUv3, hence it doesn't need the BDF2SID mapping
>>>> present in the existing cfg_1_9_0 ops. This is fixed by introducing new ops
>>>> 'ops_1_38_0' and cfg 'cfg_1_38_0' structures. These are exactly same as the
>>>> 1_9_0 ones, but they don't have the 'config_sid()' callback that handles the
>>>> BDF2SID mapping in the hardware. These new structures could also be used by the
>>>> future SoCs making use of SMMUv3."
>>> Don't we need something like this for sc8280xp and other platforms using
>>> SMMUv3 as well?
>> From what I know, sc8280xp and other qcom platforms are not using SMMUv3.
> sc8280xp indeed has SMMUv3 for PCIe, but I'm not sure how it is configured. So
> not completely sure whether we can avoid the mapping table or not.
>
> Qiang, please check with the hw team and let us know.
Sure, will update once I get any response from hw team.

Thanks,
Qiang
>
> - Mani
>