Re: [PATCH v2 00/17] hw/arm/aspeed: AST1700 LTPI support and device hookups

["Cédric Le Goater" <clg@redhat.com>]

On 11/5/25 04:58, Kane Chen wrote:
> From: Kane-Chen-AS <kane_chen@aspeedtech.com>
> 
> Hi all,
> 
> LTPI (LVDS Tunneling Protocol & Interface) is defined in the OCP DC-SCM
> 2.0 specification (see Figure 2):
> https://www.opencompute.org/documents/ocp-dc-scm-2-0-ltpi-ver-1-0-pdf
> 
> LTPI provides a protocol and physical interface for tunneling various
> low-speed signals between the Host Processor Module (HPM) and the
> Satellite Controller Module (SCM). In Figure 2 of the specification,
> the AST27x0 SoC (left) integrates two LTPI controllers, allowing it to
> connect to up to two AST1700 boards. On the other side, the AST1700
> consolidates HPM FPGA functions and multiple peripheral interfaces
> (GPIO, UART, I2C, I3C, etc.) onto a single board.
> 
> Because the AST1700 exposes additional I/O interfaces (GPIO, I2C, I3C,
> and others), it acts as an I/O expander. Once connected over LTPI,
> the AST27x0 can control additional downstream devices through this link.
> 
> This patch series introduces a basic LTPI controller model and wires it
> into the AST27x0 SoC. It also adds the AST1700-specific LTPI expander
> device and gradually connects common peripherals on the AST1700 model.
> For blocks that are not yet functionally implemented (I3C, SGPIOM, PWM),
> their MMIO regions are modeled as unimplemented devices to reserve
> address space and make the missing functionality explicit, ensuring that
> guest probing remains stable.
> 
> In the official release images, the AST1700 functions are not included
> by default. To test the AST1700-related functionality, please include
> the following DTS files for probing:
> https://github.com/AspeedTech-BMC/linux/blob/aspeed-master-v6.6/arch/arm64/boot/dts/aspeed/aspeed-ltpi0.dtsi
> https://github.com/AspeedTech-BMC/linux/blob/aspeed-master-v6.6/arch/arm64/boot/dts/aspeed/aspeed-ltpi1.dtsi
> 
> After including these DTS files in the BMC image, you can verify LTPI
> functionality using the following scenarios:
> 
> 1. In U-Boot:
>     Run the ltpi command to trigger the LTPI connection and display the
>     current connection status.
> 2. In BMC Linux:
>     Run i2cdetect -y <16-38> to scan and test the I2C buses exposed by
>     the AST1700.
> 
> Any feedback or suggestions are appreciated!
> 

Thanks for the update. The models look better. Let's consider them
for QEMU 11.0.


Did you run "make check" and "make check-functional" ?

Thanks,

C.