[PATCH V2 0/7] Add power domain and MSI functionality with PCIe host generic ECAM driver

[Mayank Rana]

On 7/24/2024 6:34 AM, Dmitry Baryshkov wrote:
> On Wed, 24 Jul 2024 at 16:31, Manivannan Sadhasivam
> <manivannan.sadhasivam at linaro.org> wrote:
>>
>> On Wed, Jul 24, 2024 at 10:12:17AM +0300, Dmitry Baryshkov wrote:
>>> On Wed, 24 Jul 2024 at 06:58, Mayank Rana <quic_mrana at quicinc.com> wrote:
>>>>
>>>>
>>>>
>>>> On 7/23/2024 7:13 PM, Dmitry Baryshkov wrote:
>>>>> On Mon, Jul 15, 2024 at 11:13:28AM GMT, Mayank Rana wrote:
>>>>>> Based on previously received feedback, this patch series adds functionalities
>>>>>> with existing PCIe host generic ECAM driver (pci-host-generic.c) to get PCIe
>>>>>> host root complex functionality on Qualcomm SA8775P auto platform.
>>>>>>
>>>>>> Previously sent RFC patchset to have separate Qualcomm PCIe ECAM platform driver:
>>>>>> https://lore.kernel.org/all/d10199df-5fb3-407b-b404-a0a4d067341f@quicinc.com/T/
>>>>>>
>>>>>> 1. Interface to allow requesting firmware to manage system resources and performing
>>>>>> PCIe Link up (devicetree binding in terms of power domain and runtime PM APIs is used in driver)
>>>>>> 2. Performing D3 cold with system suspend and D0 with system resume (usage of GenPD
>>>>>> framework based power domain controls these operations)
>>>>>> 3. SA8775P is using Synopsys Designware PCIe controller which supports MSI controller.
>>>>>> This MSI functionality is used with PCIe host generic driver after splitting existing MSI
>>>>>> functionality from pcie-designware-host.c file into pcie-designware-msi.c file.
>>>>>
>>>>> Please excuse me my ignorance if this is described somewhere. Why are
>>>>> you using DWC-specific MSI handling instead of using GIC ITS?
>>>> Due to usage of GIC v3 on SA8775p with Gunyah hypervisor, we have
>>>> limitation of not supporting GIC ITS
>>>> functionality. We considered other approach as usage of free SPIs (not
>>>> available, limitation in terms of mismatch between number of SPIs
>>>> available with physical GIC vs hypervisor) and extended SPIs (not
>>>> supported with GIC hardware). Hence we just left with DWC-specific MSI
>>>> controller here for MSI functionality.
>>>
>>> ... or extend Gunyah to support GIC ITS. I'd say it is a significant
>>> deficiency if one can not use GIC ITS on Gunyah platforms.
>>>
>>
>> It if were possible, Qcom would've went with that. Unfortunately, it is not.
> 
> Ack.
> Mayank, if the patch gets resent for any reason, please add this to
> the commit message.
ACK.

Regards,
Mayank
>>
>> - Mani
>>
>> --
>> மணிவண்ணன் சதாசிவம்
> 
> 
>