lowRISC/opentitan
Nov 2023 – Dec 2025
22 Months active
Languages Used
CSystemVerilogPythonHjsonMarkdownSVGC++HCL
Technical Skills
C programmingDMA configurationSPI communicationembedded systemshardware interfacingtesting frameworks
Robert Schilling
PROFILE
Robert Schilling
Robert Schilling developed and maintained core hardware and verification infrastructure for the lowRISC/opentitan repository, focusing on scalable SoC integration, security, and test automation. He engineered features such as register access control logic (RACL), DMA enhancements, and parameterized hardware modules, using SystemVerilog and Python to enable flexible, secure hardware design. His work included templated IP generation, device tree integration, and robust build system improvements, addressing both RTL correctness and CI-driven validation. By implementing detailed logging, formal verification, and modular configuration, Robert improved system reliability, reduced integration risk, and accelerated onboarding of new IP, demonstrating deep technical understanding and maintainable engineering practices.
Overall Statistics
Feature vs Bugs
71%Features
Repository Contributions
628Total
Bugs
100
Commits
628
Features
243
Lines of code
640,685
Activity Months22
Your Network
122 peopleSame Organization
@rivosinc.com28
Work History
December 2025
1 Commits • 1 Features
Dec 1, 2025December 2025: Delivered Power Manager External Reset Acknowledgment Signal in lowRISC/opentitan to improve reset handling clarity and reliability. Implemented a dedicated acknowledgment path for external resets, ensuring ext reset and its ack are not muxed on the same wire, thereby reducing contention and timing hazards in RTL. The change spans hardware/pwrmgr/rtl and is committed as e7ff16dbd0f077ff6bd70e6952597ac68eb0864b. Signed-off-by: Robert Schilling. Business value: increases system stability for external reset flows and reduces debugging/maintenance overhead in reset plumbing.
1 Commits • 1 Features
Dec 1, 2025December 2025: Delivered Power Manager External Reset Acknowledgment Signal in lowRISC/opentitan to improve reset handling clarity and reliability. Implemented a dedicated acknowledgment path for external resets, ensuring ext reset and its ack are not muxed on the same wire, thereby reducing contention and timing hazards in RTL. The change spans hardware/pwrmgr/rtl and is committed as e7ff16dbd0f077ff6bd70e6952597ac68eb0864b. Signed-off-by: Robert Schilling. Business value: increases system stability for external reset flows and reduces debugging/maintenance overhead in reset plumbing.
December 2025
November 2025
47 Commits • 23 Features
Nov 1, 2025November 2025 (lowRISC/opentitan): Delivered expanded automated DV coverage and significant test infrastructure improvements. Key outcomes include enabling and maintaining the Darjeeling test suite with system-level tests and pmp smoketests, porting a broad set of tests to multitop for scalable CI, and stabilizing the build/test pipeline with lint/config updates. These efforts increased test coverage, reduced investigation time, and improved hardware DV portability and maintainability, delivering tangible business value through faster release cycles and higher confidence in silicon bring-up.
November 2025
47 Commits • 23 Features
Nov 1, 2025November 2025 (lowRISC/opentitan): Delivered expanded automated DV coverage and significant test infrastructure improvements. Key outcomes include enabling and maintaining the Darjeeling test suite with system-level tests and pmp smoketests, porting a broad set of tests to multitop for scalable CI, and stabilizing the build/test pipeline with lint/config updates. These efforts increased test coverage, reduced investigation time, and improved hardware DV portability and maintainability, delivering tangible business value through faster release cycles and higher confidence in silicon bring-up.
October 2025
20 Commits • 7 Features
Oct 1, 2025In October 2025, the opentitan effort delivered a set of cross-cutting features and reliability improvements spanning RTL, DV, tooling, and device-tree handling. The work improves debug policy governance, expands hardware configuration support, and strengthens maintainability, verification, and documentation to enable faster integration of next hardware iterations and reduced risk across the deployment pipeline.
20 Commits • 7 Features
Oct 1, 2025In October 2025, the opentitan effort delivered a set of cross-cutting features and reliability improvements spanning RTL, DV, tooling, and device-tree handling. The work improves debug policy governance, expands hardware configuration support, and strengthens maintainability, verification, and documentation to enable faster integration of next hardware iterations and reduced risk across the deployment pipeline.
October 2025
September 2025
68 Commits • 12 Features
Sep 1, 2025September 2025 monthly summary for opentitan focused on security hardening, RTL improvements, and DT integration, delivering concrete features, robust CI validation, and enhanced key management. The month advanced hardware-software integration, improved security posture, and maintainability through Device Tree migrations and CI checks.
September 2025
68 Commits • 12 Features
Sep 1, 2025September 2025 monthly summary for opentitan focused on security hardening, RTL improvements, and DT integration, delivering concrete features, robust CI validation, and enhanced key management. The month advanced hardware-software integration, improved security posture, and maintainability through Device Tree migrations and CI checks.
August 2025
44 Commits • 21 Features
Aug 1, 2025August 2025: Delivered scalability, reliability, and security improvements across opentitan, focusing on interrupt handling, IP generation tooling, and OTP/secrets hygiene. Enabled 1024-source interrupt support, extended dtgen/ipgen types to uint16, standardized ipgen IP generation, and refactored core/topgen components for maintainability. Strengthened build-time quality, linting, and secret management to reduce risk and accelerate future feature work, while improving OTP/map integration and alert rendering for Darjeeling and EARLGREY. Implemented PRNG seeding improvements and RACL sizing for better hardware scalability and security, with targeted refactors to core files and primitives.
44 Commits • 21 Features
Aug 1, 2025August 2025: Delivered scalability, reliability, and security improvements across opentitan, focusing on interrupt handling, IP generation tooling, and OTP/secrets hygiene. Enabled 1024-source interrupt support, extended dtgen/ipgen types to uint16, standardized ipgen IP generation, and refactored core/topgen components for maintainability. Strengthened build-time quality, linting, and secret management to reduce risk and accelerate future feature work, while improving OTP/map integration and alert rendering for Darjeeling and EARLGREY. Implemented PRNG seeding improvements and RACL sizing for better hardware scalability and security, with targeted refactors to core files and primitives.
August 2025
July 2025
36 Commits • 12 Features
Jul 1, 2025July 2025 monthly summary for lowRISC/openTitan focused on delivering measurable business value through a mix of timing/configuration improvements, security hardening, and DV/testbench realism across RTL, IPs, and top-level integration. The month emphasizes configurable timing controls, improved observability, and robust build/quality hygiene to accelerate DV cycles and reduce integration risk.
July 2025
36 Commits • 12 Features
Jul 1, 2025July 2025 monthly summary for lowRISC/openTitan focused on delivering measurable business value through a mix of timing/configuration improvements, security hardening, and DV/testbench realism across RTL, IPs, and top-level integration. The month emphasizes configurable timing controls, improved observability, and robust build/quality hygiene to accelerate DV cycles and reduce integration risk.
June 2025
30 Commits • 11 Features
Jun 1, 2025June 2025 monthly summary for lowRISC/opentitan: Delivered notable feature enhancements in ac_range_check and entropy_src, applied corefiles improvements, and substantial RTL/test reliability fixes. Focused on reliability, security, and maintainability with broader test coverage through multitop test porting, lint/config hardening, and build workflow improvements across hardware and software stacks.
30 Commits • 11 Features
Jun 1, 2025June 2025 monthly summary for lowRISC/opentitan: Delivered notable feature enhancements in ac_range_check and entropy_src, applied corefiles improvements, and substantial RTL/test reliability fixes. Focused on reliability, security, and maintainability with broader test coverage through multitop test porting, lint/config hardening, and build workflow improvements across hardware and software stacks.
June 2025
May 2025
13 Commits • 3 Features
May 1, 2025May 2025 monthly summary for lowRISC/opentitan: Delivered critical RTL correctness fixes, formal verification improvements, and tooling/maintenance updates. Key outcomes include updated DMA documentation; RTL fixes for OTP address calculation and QE behavior; Xcelium simulator warning resolved; Ibex core upgraded with formal verification improvements and Nix-based env; tooling and RTL cleanup improving module detection, parameter defaults, and linting waivers. These changes reduce RTL risk, improve validation accuracy, accelerate onboarding for formal flows, and enhance overall development reliability.
May 2025
13 Commits • 3 Features
May 1, 2025May 2025 monthly summary for lowRISC/opentitan: Delivered critical RTL correctness fixes, formal verification improvements, and tooling/maintenance updates. Key outcomes include updated DMA documentation; RTL fixes for OTP address calculation and QE behavior; Xcelium simulator warning resolved; Ibex core upgraded with formal verification improvements and Nix-based env; tooling and RTL cleanup improving module detection, parameter defaults, and linting waivers. These changes reduce RTL risk, improve validation accuracy, accelerate onboarding for formal flows, and enhance overall development reliability.
April 2025
11 Commits • 3 Features
Apr 1, 2025April 2025 monthly summary for lowRISC/opentitan focusing on security, traceability, and maintainability improvements across core peripherals and hardware IP packaging.
11 Commits • 3 Features
Apr 1, 2025April 2025 monthly summary for lowRISC/opentitan focusing on security, traceability, and maintainability improvements across core peripherals and hardware IP packaging.
April 2025
March 2025
41 Commits • 17 Features
Mar 1, 2025March 2025: Delivered end-to-end IP templating and ipgen integration for GPIO and PWM, enabling templated IP blocks and automated top regeneration. Implemented configurable hardware parameters (outstanding SRAM transactions, PWM channels) and advanced IP hygiene (optional flash-key interface in otp_ctrl, always-on late debug). Updated the ibex core to the latest upstream and performed RTL/lint improvements to boost reliability and synthesis safety. Strengthened the ipgen/topgen pipeline with robust handling of undefined modules and unique IP listings, and improved build tooling and cross-platform compatibility. These changes reduce manual collateral, accelerate IP reuse, and enhance traceability and debugging across the SoC.
March 2025
41 Commits • 17 Features
Mar 1, 2025March 2025: Delivered end-to-end IP templating and ipgen integration for GPIO and PWM, enabling templated IP blocks and automated top regeneration. Implemented configurable hardware parameters (outstanding SRAM transactions, PWM channels) and advanced IP hygiene (optional flash-key interface in otp_ctrl, always-on late debug). Updated the ibex core to the latest upstream and performed RTL/lint improvements to boost reliability and synthesis safety. Strengthened the ipgen/topgen pipeline with robust handling of undefined modules and unique IP listings, and improved build tooling and cross-platform compatibility. These changes reduce manual collateral, accelerate IP reuse, and enhance traceability and debugging across the SoC.
February 2025
56 Commits • 21 Features
Feb 1, 2025February 2025 (2025-02) monthly summary for lowRISC/opentitan focusing on business value and technical excellence. Delivered substantial enhancements across AC range checks, RACL integration, risk-reducing bug fixes, and infrastructure improvements enabling security features and reliable deployment. Implemented robust top-level regeneration and topology updates to reflect ongoing changes, improved test coverage, and expanded hardware capabilities.
56 Commits • 21 Features
Feb 1, 2025February 2025 (2025-02) monthly summary for lowRISC/opentitan focusing on business value and technical excellence. Delivered substantial enhancements across AC range checks, RACL integration, risk-reducing bug fixes, and infrastructure improvements enabling security features and reliable deployment. Implemented robust top-level regeneration and topology updates to reflect ongoing changes, improved test coverage, and expanded hardware capabilities.
February 2025
January 2025
121 Commits • 53 Features
Jan 1, 2025Summary for 2025-01: Delivered a suite of HDL, IP-generation, and system integration improvements across the OpenTitan repository, emphasizing performance, security, and maintainability. Key features include enabling Ibex pipelining to boost instruction throughput, standardizing HDL semantics with localparam usage, expanding Darjeeling user-bit support (27 and 28 bits) and aligning CSB width to NumCS, plus exposing I2C RAM configuration at the top level. Major hardware security and reliability work includes RACL integration across modules with RAC L protections, RACL-protected TLUL adapters, and re-generation of top designs via ipgen for rv_core_ibex; these changes enable safer routing and more predictable security policies. Observability and validation gains were achieved by adding missing incoming_alert definitions, augmenting topgen validations, and applying ASSERT_KNOWN to new IP outputs across multiple modules, as well as templating RTL/DV files to simplify reuse. Foundational work in build and naming consistency (rename/refactor of alert_handler_pkg, module_instance_name handling, and topgen utilities) lays groundwork for easier maintenance and scalable growth. Business value includes higher throughput, stronger security posture, faster onboarding of new IP, and reduced maintenance burden through templating and standardized HDL semantics.
January 2025
121 Commits • 53 Features
Jan 1, 2025Summary for 2025-01: Delivered a suite of HDL, IP-generation, and system integration improvements across the OpenTitan repository, emphasizing performance, security, and maintainability. Key features include enabling Ibex pipelining to boost instruction throughput, standardizing HDL semantics with localparam usage, expanding Darjeeling user-bit support (27 and 28 bits) and aligning CSB width to NumCS, plus exposing I2C RAM configuration at the top level. Major hardware security and reliability work includes RACL integration across modules with RAC L protections, RACL-protected TLUL adapters, and re-generation of top designs via ipgen for rv_core_ibex; these changes enable safer routing and more predictable security policies. Observability and validation gains were achieved by adding missing incoming_alert definitions, augmenting topgen validations, and applying ASSERT_KNOWN to new IP outputs across multiple modules, as well as templating RTL/DV files to simplify reuse. Foundational work in build and naming consistency (rename/refactor of alert_handler_pkg, module_instance_name handling, and topgen utilities) lays groundwork for easier maintenance and scalable growth. Business value includes higher throughput, stronger security posture, faster onboarding of new IP, and reduced maintenance burden through templating and standardized HDL semantics.
December 2024
38 Commits • 18 Features
Dec 1, 2024December 2024 performance snapshot for lowRISC/opentitan. Delivered security, build readiness, and RTL/SoC integration improvements across the OpenTitan repository, with a focus on enabling secure hardware interactions, scalable build processes for Darjeeling, and enhanced debugging support. Key features were implemented across reggen, rv_core_ibex, Topgen, and memory/RAM subsystems, along with substantial DFT and peripheral enhancements. Resolved critical corefile issues and improved code quality with lint fixes, contributing to more reliable releases and faster iteration cycles.
38 Commits • 18 Features
Dec 1, 2024December 2024 performance snapshot for lowRISC/opentitan. Delivered security, build readiness, and RTL/SoC integration improvements across the OpenTitan repository, with a focus on enabling secure hardware interactions, scalable build processes for Darjeeling, and enhanced debugging support. Key features were implemented across reggen, rv_core_ibex, Topgen, and memory/RAM subsystems, along with substantial DFT and peripheral enhancements. Resolved critical corefile issues and improved code quality with lint fixes, contributing to more reliable releases and faster iteration cycles.
December 2024
November 2024
78 Commits • 29 Features
Nov 1, 2024November 2024 monthly summary for lowRISC/opentitan focusing on business value, reliability, and technical depth. The month emphasized completing end-to-end Darjeeling integration with the topgen/template flow, expanding IP generation and parameterization to improve configurability, and enhancing observability and debug capabilities. Deliveries targeted reduction of risk, faster integration, and scalable hardware configuration across targets.
November 2024
78 Commits • 29 Features
Nov 1, 2024November 2024 monthly summary for lowRISC/opentitan focusing on business value, reliability, and technical depth. The month emphasized completing end-to-end Darjeeling integration with the topgen/template flow, expanding IP generation and parameterization to improve configurability, and enhancing observability and debug capabilities. Deliveries targeted reduction of risk, faster integration, and scalable hardware configuration across targets.
October 2024
13 Commits • 5 Features
Oct 1, 2024October 2024 monthly summary for lowRISC/opentitan focused on delivering reliable hardware verification tooling, expanding automation, and improving maintainability. The team emphasized features that enable scalable simulation, robust alerting, and accelerated cryptographic IP integration, while addressing verification environment compatibility and documentation alignment. The work balanced performance improvements with security and correctness fixes across the RTL/DV stack.
13 Commits • 5 Features
Oct 1, 2024October 2024 monthly summary for lowRISC/opentitan focused on delivering reliable hardware verification tooling, expanding automation, and improving maintainability. The team emphasized features that enable scalable simulation, robust alerting, and accelerated cryptographic IP integration, while addressing verification environment compatibility and documentation alignment. The work balanced performance improvements with security and correctness fixes across the RTL/DV stack.
October 2024
September 2024
3 Commits • 2 Features
Sep 1, 2024September 2024 monthly summary for lowRISC/opentitan: Delivered preparatory work for DMI TL-UL conversion and registry modularization, and introduced DMA status interrupts to enhance interrupt handling. This lays groundwork for migration to a real TL-UL interface and modular lifecycle architecture, improving system reliability and maintainability.
September 2024
3 Commits • 2 Features
Sep 1, 2024September 2024 monthly summary for lowRISC/opentitan: Delivered preparatory work for DMI TL-UL conversion and registry modularization, and introduced DMA status interrupts to enhance interrupt handling. This lays groundwork for migration to a real TL-UL interface and modular lifecycle architecture, improving system reliability and maintainability.
August 2024
2 Commits • 1 Features
Aug 1, 2024Month: 2024-08 — Focused feature delivery in lowRISC/opentitan: DMA Transfer Enhancements. No major bugs fixed this month. Delivered a chunk-done interrupt and flexible address increment options to improve DMA throughput and configurability. This work enables finer-grained transfer signaling and supports diverse data layouts, reducing software overhead and improving system-level data movement reliability.
2 Commits • 1 Features
Aug 1, 2024Month: 2024-08 — Focused feature delivery in lowRISC/opentitan: DMA Transfer Enhancements. No major bugs fixed this month. Delivered a chunk-done interrupt and flexible address increment options to improve DMA throughput and configurability. This work enables finer-grained transfer signaling and supports diverse data layouts, reducing software overhead and improving system-level data movement reliability.
August 2024
July 2024
1 Commits • 1 Features
Jul 1, 2024July 2024 — Delivered the DMA Multi-Chunk Transfer Status Feedback feature in lowRISC/opentitan by introducing a new STATUS.chunk_done bit to signal per-chunk completion in multi-chunk DMA transfers. This enhances observability, control, and reliability of DMA data movement. No major bugs were recorded for this repo in the provided data. Overall impact: improved DMA feedback loop, enabling faster issue diagnosis and safer multi-chunk transfers. Technologies demonstrated: RTL/hw design, DMA subsystem work, and hardware-software integration in a version-controlled environment.
July 2024
1 Commits • 1 Features
Jul 1, 2024July 2024 — Delivered the DMA Multi-Chunk Transfer Status Feedback feature in lowRISC/opentitan by introducing a new STATUS.chunk_done bit to signal per-chunk completion in multi-chunk DMA transfers. This enhances observability, control, and reliability of DMA data movement. No major bugs were recorded for this repo in the provided data. Overall impact: improved DMA feedback loop, enabling faster issue diagnosis and safer multi-chunk transfers. Technologies demonstrated: RTL/hw design, DMA subsystem work, and hardware-software integration in a version-controlled environment.
June 2024
1 Commits • 1 Features
Jun 1, 2024June 2024 monthly summary for lowRISC/opentitan: Delivered parametrized inter-module signal widths to enable dynamic width definitions across configurations, improving configurability, modularity, and scalability of hardware designs. This change supports broader variant testing and reduces rework by standardizing width-parametric interfaces across modules. Key commit includes [topgen] Support for parametrized inter-module signals (d0b70aef0a481ce35f290a8960e73156d33caeec).
1 Commits • 1 Features
Jun 1, 2024June 2024 monthly summary for lowRISC/opentitan: Delivered parametrized inter-module signal widths to enable dynamic width definitions across configurations, improving configurability, modularity, and scalability of hardware designs. This change supports broader variant testing and reduces rework by standardizing width-parametric interfaces across modules. Key commit includes [topgen] Support for parametrized inter-module signals (d0b70aef0a481ce35f290a8960e73156d33caeec).
June 2024
January 2024
1 Commits
Jan 1, 2024January 2024 focused on stabilizing Ibex I-cache scramble timing constraint handling within lowRISC/opentitan. Implemented a targeted timing window increase to ensure proper handling of scramble key requests after fence instructions, improving reliability and security in the I-cache scramble flow.
January 2024
1 Commits
Jan 1, 2024January 2024 focused on stabilizing Ibex I-cache scramble timing constraint handling within lowRISC/opentitan. Implemented a targeted timing window increase to ensure proper handling of scramble key requests after fence instructions, improving reliability and security in the I-cache scramble flow.
December 2023
1 Commits • 1 Features
Dec 1, 2023December 2023 monthly summary: Delivered end-to-end DMA abort test coverage for lowRISC/opentitan, reinforcing robustness of the DMA controller under abort scenarios and enabling regression testing across the DMA-SPI path. The work improved test coverage, reduced risk in abort-related edge cases, and supported CI-driven verification.
1 Commits • 1 Features
Dec 1, 2023December 2023 monthly summary: Delivered end-to-end DMA abort test coverage for lowRISC/opentitan, reinforcing robustness of the DMA controller under abort scenarios and enabling regression testing across the DMA-SPI path. The work improved test coverage, reduced risk in abort-related edge cases, and supported CI-driven verification.
December 2023
November 2023
2 Commits • 1 Features
Nov 1, 2023Month: 2023-11 — Performance review-ready monthly summary for lowRISC/OpenTitan repository focusing on key accomplishments, feature delivery, and business value. This month delivered a new DMA inline hashing testing framework with SPI host transaction handling improvements and a refactor to separate configuration and FIFO read paths for SPI host. No explicit bug fixes were reported; however, the changes reduce risk by improving test coverage, clarity, and maintainability. The work strengthens hardware test coverage for DMA, SPI host, and DIF layers, enabling more reliable regression testing and faster debugging.
November 2023
2 Commits • 1 Features
Nov 1, 2023Month: 2023-11 — Performance review-ready monthly summary for lowRISC/OpenTitan repository focusing on key accomplishments, feature delivery, and business value. This month delivered a new DMA inline hashing testing framework with SPI host transaction handling improvements and a refactor to separate configuration and FIFO read paths for SPI host. No explicit bug fixes were reported; however, the changes reduce risk by improving test coverage, clarity, and maintainability. The work strengthens hardware test coverage for DMA, SPI host, and DIF layers, enabling more reliable regression testing and faster debugging.
Activity
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Quality Metrics
Correctness94.0%
Maintainability93.2%
Architecture92.8%
Performance87.4%
AI Usage20.4%
Skills & Technologies
Programming Languages
Jinja Jinja2AssemblyBUILDBashBazelBzlCC++Core
Technical Skills
AES ImplementationASIC DesignAccess ControlAccess Control LogicArbiter DesignAssertion WritingAssertion-Based VerificationAssertionsBackend DevelopmentBazelBuild SystemBuild System ConfigurationBuild SystemsC ProgrammingC programming
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