On Tue, Dec 23, 2025 at 5:42 PM Kane Chen <[email protected]> wrote: > > From: Kane-Chen-AS <[email protected]> > > 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 is based on the SGPIO changes: > https://patchwork.kernel.org/project/qemu-devel/patch/[email protected]/ > > It introduces a basic LTPI controller model and wires it into the > AST27x0 SoC. The series also adds the AST1700-specific LTPI expander > device and incrementally connects common peripherals on the AST1700 > model. For the I3C block, which may cause kernel crashes, its MMIO > region is modeled as an unimplemented device to reserve address space > and make the missing functionality explicit, ensuring stable guest > probing. > > 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! > > Kane >
Adding the explanation of the tested tag in every patch feels unnecessary since the tests applied equally to all patches. However, I didn't want to add the tag without any explanation, so I figured I might as well reply to the cover letter. I tested between patches to make sure all our internal tests passed and there was no unexpected breakages, and once the whole patchset landed tested against our internal ast2700 machines and was able to see the i2c buses and attach devices to them. > --- > > ChangeLog > --------- > v4: > - Add missing Signed-off-by > - Fix checkpatch.pl warnings > - Refine code structure > - Enable AST1700 support only after all devices are ready > > v3: > - Add PWM model > - Integrate the SGPIO model > - Fix I2C test case failure > - Refine code structure > > v2: > - Separate the AST1700 model into a standalone implementation > - Refine the mechanism for assigning the AST1700 board number > > v1: > - Initial version > --- > > Kane-Chen-AS (19): > hw/misc: Add LTPI controller > hw/arm/aspeed: Attach LTPI controller to AST27X0 platform > hw/misc: Add basic Aspeed PWM model > hw/arm/aspeed: Add AST1700 LTPI expander device model > hw/arm/aspeed: Integrate AST1700 device into AST27X0 > hw/arm/aspeed: Integrate interrupt controller for AST1700 > hw/arm/aspeed: Attach LTPI controller to AST1700 model > hw/arm/aspeed: Attach UART device to AST1700 model > hw/arm/aspeed: Attach SRAM device to AST1700 model > hw/arm/aspeed: Attach SPI device to AST1700 model > hw/arm/aspeed: Attach ADC device to AST1700 model > hw/arm/aspeed: Attach SCU device to AST1700 model > hw/arm/aspeed: Attach GPIO device to AST1700 model > hw/arm/aspeed: attach I2C device to AST1700 model > hw/arm/aspeed: Attach WDT device to AST1700 model > hw/arm/aspeed: Attach PWM device to AST1700 model > hw/arm/aspeed: Attach SGPIOM device to AST1700 model > hw/arm/aspeed: Model AST1700 I3C block as unimplemented device > hw/arm/aspeed: Enable AST1700 IO expander support > > include/hw/arm/aspeed_ast1700.h | 53 +++++++ > include/hw/arm/aspeed_soc.h | 25 ++- > include/hw/i2c/aspeed_i2c.h | 1 + > include/hw/intc/aspeed_intc.h | 2 + > include/hw/misc/aspeed_ltpi.h | 33 ++++ > include/hw/misc/aspeed_pwm.h | 31 ++++ > hw/arm/aspeed_ast1700.c | 268 ++++++++++++++++++++++++++++++++ > hw/arm/aspeed_ast27x0.c | 165 ++++++++++++++++++-- > hw/i2c/aspeed_i2c.c | 19 ++- > hw/intc/aspeed_intc.c | 60 +++++++ > hw/misc/aspeed_ltpi.c | 193 +++++++++++++++++++++++ > hw/misc/aspeed_pwm.c | 121 ++++++++++++++ > hw/arm/meson.build | 1 + > hw/misc/meson.build | 2 + > hw/misc/trace-events | 4 + > 15 files changed, 959 insertions(+), 19 deletions(-) > create mode 100644 include/hw/arm/aspeed_ast1700.h > create mode 100644 include/hw/misc/aspeed_ltpi.h > create mode 100644 include/hw/misc/aspeed_pwm.h > create mode 100644 hw/arm/aspeed_ast1700.c > create mode 100644 hw/misc/aspeed_ltpi.c > create mode 100644 hw/misc/aspeed_pwm.c > > -- > 2.43.0 >
