Re: [PATCH v2 0/2] soc: aspeed: ipmi: add KCS Channel 4 over PCIe

> The PCIe-to-LPC bridge on the AST2600 exposes 4 channels, matching the LP=
C=0A=
> controller's own KCS1-4, not just channel 4.=0A=
> It would be better If you can provide a way to handle multiple LPC contro=
ller for=0A=
> kcs channels.=0A=
=0A=
I raised an RFC to discuss support for multiple LPC controllers in [1].=0A=
=0A=
Perhaps we should first take other people's opinions into consideration=0A=
before moving forward.=0A=
=0A=
[1] https://lkml.org/lkml/2026/7/23/429=0A=
=0A=
> >=0A=
> > The ASPEED AST2600 has a PCIe to LPC controller. It includes a KCS inte=
rface=0A=
> > on channel 4. This is a fully KCS-compatible interface that is exposed =
over=0A=
> > PCIe.=0A=
> >=0A=
> > Add pcie_kcs4 to existing LPC bus in aspeed-g6.dtsi.=0A=
> > Modify kcs_bmc_aspeed driver to detect the PCIe over LPC channel.=0A=
> >=0A=
> > In the driver, this PCIe over LPC channel will be detected as Channel 5=
.=0A=
> > In the datasheet this is defined as Channel 4 over PCIe.=0A=
> >=0A=
> > The Channel 4 name is still referenced in the offsets macros.=0A=
> >=0A=
> > The host need a driver to activate the MSI interrupts with the PCIe BMC=
=0A=
> > Device.=0A=
> >=0A=
> > Tests:=0A=
> > With the patch [2] adding PCIe BMC device for Virtual UART, the MSI=0A=
> > interrupts are correctly setups. The Host driver is build and side load=
ed on the=0A=
> > host. The ipmi_si driver on the host is loaded manually with the KCS ad=
dress=0A=
> > given by hand. 'ipmitool mc info' is run to confirm it's working.=0A=
> >=0A=
> > Tested on : Asus IPMI Expansion Card, AST2600.=0A=
> > ```=0A=
> > # insmod aspeed-host-bmc-dev.ko=0A=
> > # lspci -vvv -d 1a03:2402=0A=
> > 02:01.0 Unassigned class [ff00]: ASPEED Technology, Inc. Device 2402=0A=
> >        Subsystem: ASPEED Technology, Inc. Device 2402=0A=
> >        Control: I/O- Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop-=0A=
> > ParErr- Stepping- SERR- FastB2B- DisINTx+=0A=
> >        Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=3Dmedium > >TAb=
ort-=0A=
> > <TAbort- <MAbort- > >SERR- <PERR- INTx-=0A=
> >        Latency: 0=0A=
> >        Interrupt: pin A routed to IRQ 154=0A=
> >        IOMMU group: 12=0A=
> >        Region 0: Memory at 82080000 (32-bit, non-prefetchable) [size=3D=
4K]=0A=
> >        Region 1: Memory at 82040000 (32-bit, non-prefetchable) [size=3D=
256K]=0A=
> >        Capabilities: [40] Power Management version 3=0A=
> >                Flags: PMEClk- DSI- D1+ D2+ AuxCurrent=3D375mA=0A=
> > PME(D0+,D1+,D2+,D3hot+,D3cold+)=0A=
> >                Status: D0 NoSoftRst- PME-Enable- DSel=3D0 DScale=3D0 PM=
E-=0A=
> >        Capabilities: [50] MSI: Enable+ Count=3D32/32 Maskable- 64bit+=
=0A=
> >                Address: 00000000fee00818  Data: 0000=0A=
> >        Kernel driver in use: aspeed-host-bmc-dev=0A=
> >=0A=
> > # modprobe ipmi_si type=3Dkcs addrs=3D0x82040E88 regspacings=3D4 regsiz=
es=3D1=0A=
> > regshifts=3D0=0A=
> >=0A=
> > # ipmitool mc info=0A=
> > Device ID                 : 32=0A=
> > Device Revision           : 1=0A=
> > Firmware Revision         : 26.04=0A=
> > IPMI Version              : 2.0=0A=
> > Manufacturer ID           : 2623=0A=
> > Manufacturer Name         : ASUSTek Computer Inc.=0A=
> > ...=0A=
> > ```=0A=
> >=0A=
> > The original patch [1] review set to use the existing LPC bus and modif=
y the=0A=
> > kcs_bmc_aspeed driver.=0A=
> >=0A=
> > [1]=0A=
> > https://lore.kernel.org/linux-aspeed/de49f2032f5b1f170161dcd6191c0daa48=
f0=0A=
> > [email protected]/=0A=
> > [2]=0A=
> > https://lore.kernel.org/linux-aspeed/51e455417bdcfe608270c6cb2806b1fd97=
1f=0A=
> > [email protected]/=0A=
> >=0A=
> > Gr=E9goire Layet (2):=0A=
> >   ipmi: kcs_bmc_aspeed: g6: Add KCS Channel 4 over PCIe=0A=
> >   ARM: dts: aspeed-g6: add pcie-kcs4=0A=
> >=0A=
> >  arch/arm/boot/dts/aspeed/aspeed-g6.dtsi |  7 +++++=0A=
> >  drivers/char/ipmi/kcs_bmc_aspeed.c      | 39=0A=
> > +++++++++++++++++++++++--=0A=
> >  2 files changed, 44 insertions(+), 2 deletions(-)=0A=
> >=0A=
> >=0A=
> > base-commit: 03f906d8f5541e8bb741035981304feceed5993d=0A=
> > --=0A=
> > 2.54.0=