src/case_studies/DasharoBenchRack_study.md: Add case study

src/SUMMARY.md

@@ -22,3 +22,4 @@
   - [Ampere study](case_studies/Ampere_study.md)
   - [Google study](case_studies/Google_study.md)
   - [OCP TiogaPass](case_studies/TiogaPass.md)
+  - [Dasharo BenchRack ASRock TURIND8UD-2T/X550](case_studies/DasharoBenchRack_study.md)

src/case_studies/DasharoBenchRack_study.md

@@ -0,0 +1,300 @@
+# Dasharo BenchRack ASRock TURIND8UD-2T/X550
+
+BenchRack is [3mdeb](https://3mdeb.com/)'s modular test-bench reference design
+for open-source firmware development and validation.
+
+This case study covers the
+[Dasharo BenchRack ASRock TURIND8UD-2T/X550](https://docs.dasharo.com/variants/asrock_turind8ud/overview/) configuration,
+in which the DUT boots with [coreboot](https://www.coreboot.org/) (as
+distributed by 3mdeb) performing silicon initialization and LinuxBoot serving
+as the payload, following the same LinuxBoot adoption approach described in the
+[Ampere](Ampere_study.md) and [Google](Google_study.md) case studies.
+
+It contains the following sections:
+
+* [Reference design and goals](#reference-design-and-goals)
+* [Platform overview](#platform-overview)
+* [Firmware architecture](#firmware-architecture)
+* [Build process](#build-process)
+  * [Prerequisites](#prerequisites)
+  * [Build the firmware image](#build-the-firmware-image)
+* [Flashing and operation](#flashing-and-operation)
+* [Booting with LinuxBoot](#booting-with-linuxboot)
+* [Support](#support)
+  * [Hardware support](#hardware-support)
+  * [Community support](#community-support)
+  * [Professional support](#professional-support)
+* [See also](#see-also)
+
+## Reference design and goals
+
+BenchRack is intended as a reference design, not a one-off test rig. By
+standardizing how a DUT is powered, flashed, and observed, it serves several
+business and engineering goals:
+
+* **Compliance optimization showcasing** — demonstrating how an open firmware
+  stack can be tuned and evidenced to meet compliance and certification
+  requirements.
+* **Firmware due diligence and patching loop** — providing a repeatable
+  environment to audit firmware, reproduce issues, and validate patches in a
+  tight build-flash-test loop.
+* **Decomposition of complex rack systems** — breaking a complex rack system
+  into individually manageable components, enabling a divide-and-conquer
+  strategy for reasoning about and validating large systems.
+
+Because BenchRack is defined by this control-and-validation harness rather than
+by a specific board, future BenchRack configurations may host entirely
+different motherboards. This case study documents the ASRock TURIND8UD-2T/X550
+configuration.
+
+## Platform overview
+
+The device under test (DUT) in this configuration is the
+[ASRock Rack TURIND8UD-2T/X550](https://docs.dasharo.com/variants/asrock_turind8ud/overview/),
+a single-socket AMD EPYC server board:
+
+* **CPU**: single socket SP5 (LGA 6096), supporting AMD EPYC 9005 series
+  processors.
+* **Memory**: 8 DDR5 RDIMM slots (1 DIMM per channel).
+* **Expansion**: 4 PCIe 5.0 slots and 2 M.2 (PCIe 5.0 NVMe) slots.
+* **Networking**: onboard 10 GbE.
+
+The DUT is mounted in a BenchRack, which supplies remote power control, firmware
+flashing, and serial capture so the board can be validated automatically. Both
+silicon initialization (coreboot) and the payload (LinuxBoot) are open source,
+though — as on most modern x86 platforms — a few binary blobs are still required
+for silicon initialization (for example AMD PSP firmware and microcode). This
+places the platform at the most advanced practical stage of the LinuxBoot
+adoption model described in the [Ampere](Ampere_study.md) case study.
+
+## Firmware architecture
+
+The boot firmware for the DUT is largely open source, with a few binary blobs
+required for silicon initialization:
+
+* **coreboot**: performs early hardware and silicon initialization. Source is
+  available at [Dasharo/coreboot](https://github.com/Dasharo/coreboot.git).
+* **LinuxBoot**: built as the coreboot payload (u-root initramfs +
+  [flashkernel](../glossary.md)), responsible for boot device selection and
+  `kexec` into the target OS.
+
+## Build process
+
+The firmware image is a single `coreboot.rom` containing coreboot plus the
+LinuxBoot payload.
+
+### Prerequisites
+
+The recommended, reproducible build path uses the Dasharo/coreboot SDK
+container, which pins the toolchain and build dependencies.
+
+```bash
+git clone https://github.com/Dasharo/coreboot.git
+cd coreboot
+git checkout asrock_turind8ud_linuxboot_v0.9.0
+git submodule update --init --checkout
+```
+
+You must also obtain and extract blobs necessary for memory and silicon
+initialization. Please familiarize yourself with the [Dasharo terms of service](https://www.dasharo.com/pages/terms/),
+then download and extract them:
+
+```bash
+wget https://dl.3mdeb.com/open-source-firmware/Dasharo/gigabyte_mz33_ar1/uefi/v0.9.0/Turin.zip
+unzip Turin.zip -d 3rdparty/blobs/soc/amd/
+```
+
+Enter the Dasharo SDK container:
+
+```bash
+# Enter the pinned Dasharo SDK container
+docker run --rm -it \
+  -v "$PWD:/home/coreboot/coreboot" \
+  -w /home/coreboot/coreboot \
+  ghcr.io/dasharo/dasharo-sdk:v1.9.2 \
+  /bin/bash
+```
+
+### Build the firmware image
+
+From inside the SDK container:
+
+```bash
+# Select the BenchRack DUT board target and the LinuxBoot payload
+./build.sh asrock_turind8ud_linuxboot
+```
+
+The resulting flashable image is at `asrock_turind8ud_linuxboot_<version>.rom`.
+
+## Flashing and operation
+
+BenchRack provides remote flashing, power control, and serial capture for each
+DUT, enabling automated (CI) firmware deployment and testing. These are driven
+by [benchctl](https://github.com/zarhus/benchctl), a single command-line tool
+that controls the bench from a workstation or from the bench itself. For
+BenchRack it operates the [Remote Test Environment (RTE)](https://docs.dasharo.com/transparent-validation/rte/v1.1.0/specification/),
+driving the GPIO lines, the SPI mux, and host power through the RTE REST API and
+running `flashrom` over SSH — so the low-level SPI sequencing no longer has to be
+performed by hand.
+
+Select the BenchRack platform and DUT through flags (or the matching
+`BENCHCTL_*` environment variables). The `benchrack` platform defaults to the
+`asrock-turin` board profile, so `--board` can be omitted for this DUT. When run
+from a workstation, `--host` points at the RTE by IP or hostname; run directly on
+the RTE, the host is implied and the flag is dropped.
+
+To flash the host boot flash with the image built above:
+
+```bash
+# From a workstation, targeting the RTE:
+benchctl --host <RTE-IP> \
+  flash host ./asrock_turind8ud_linuxboot_<version>.rom
+```
+
+`benchctl` checks the firmware size, copies it to the RTE with `scp`, takes
+control of the SPI bus, runs the blocking flash, confirms it succeeded, and
+cleans up the temporary file. Power and serial console are managed through the
+same tool:
+
+```bash
+benchctl --host <RTE-IP> power reset   # power-cycle the DUT
+benchctl --host <RTE-IP> console       # attach to serial
+```
+
+## Booting with LinuxBoot
+
+On power-on, the DUT runs coreboot, hands off to the LinuxBoot payload, boots
+into u-root, and `kexec`s into the target OS.
+
+```text
+Welcome to LinuxBoot's Menu
+
+Enter a number to boot a kernel:
+
+01. Ubuntu
+
+02. Ubuntu, with Linux 7.0.0-27-generic
+
+03. Ubuntu, with Linux 7.0.0-27-generic (recovery mode)
+
+04. Ubuntu, with Linux 7.0.0-22-generic
+
+05. Ubuntu, with Linux 7.0.0-22-generic (recovery mode)
+
+06. Memory test (mt86+x64)
+
+07. Memory test (mt86+x64)
+
+08. Memory test (mt86+x64, serial console)
+
+09. Memory test (mt86+x64, serial console)
+
+10. Memory test (mt86+ia32)
+
+11. Memory test (mt86+ia32)
+
+12. Memory test (mt86+ia32, serial console)
+
+13. Memory test (mt86+ia32, serial console)
+
+14. Reboot
+
+15. Enter a LinuxBoot shell
+
+
+Enter an option ('01' is the default, 'e' to edit kernel cmdline):
+ >
+
+Attempting to boot LinuxImage(
+  Name: Ubuntu
+  Kernel: file:///tmp/u-root-mounts1460215710/nvme0n1p2/boot/vmlinuz-7.0.0-27-generic
+  Initrd: file:///tmp/u-root-mounts1460215710/nvme0n1p2/boot/initrd.img-7.0.0-27-generic
+  Cmdline: root=UUID=d6f381c6-1549-4560-87e9-f26d9e317ab1 ro quiet splash crashkernel=2G-4G:320M,4G-32G:512M,32G-64G:1024M,64G-128G:2048M,128G-:4096M console=ttyS0,115200
+  DTB: <nil>
+)
+```
+
+## Benchmarks
+
+### Boot Time
+
+coreboot timestamps may be obtained using `cbmem -t`:
+
+```text
+ubuntu@3mdeb:~$ sudo cbmem -t
+36 entries total:
+
+   0:1st timestamp                                     29,106,318 (0)
+  11:start of bootblock                                29,106,553 (235)
+  12:end of bootblock                                  29,109,232 (2,678)
+  13:starting to load romstage                         29,109,232 (0)
+  17:starting LZ4 decompress (ignore for x86)          29,174,661 (65,428)
+  18:finished LZ4 decompress (ignore for x86)          29,174,726 (65)
+  14:finished loading romstage                         29,174,730 (3)
+   1:start of romstage                                 29,174,734 (3)
+   4:end of romstage                                   29,174,885 (151)
+   8:starting to load ramstage                         29,174,885 (0)
+  15:starting LZMA decompress (ignore for x86)         29,536,943 (362,058)
+  16:finished LZMA decompress (ignore for x86)         29,583,677 (46,733)
+   9:finished loading ramstage                         29,586,162 (2,485)
+  10:start of ramstage                                 29,587,320 (1,158)
+  30:device enumeration                                29,587,383 (62)
+ 112:started reading uCode                             29,587,766 (383)
+ 113:finished reading uCode                            29,617,222 (29,455)
+  31:<unknown>                                         31,365,077 (1,747,855)
+  40:device configuration                              31,371,820 (6,742)
+  50:device enable                                     31,379,595 (7,775)
+  60:device initialization                             31,381,611 (2,015)
+  70:device setup done                                 31,884,811 (503,199)
+ 920:starting APOB read                                31,884,813 (2)
+ 921:starting APOB erase                               31,954,244 (69,431)
+ 922:starting APOB write                               39,357,767 (7,403,523)
+ 923:finished APOB                                     40,321,934 (964,166)
+  75:cbmem post                                        40,343,709 (21,775)
+  80:write tables                                      40,343,713 (3)
+  85:finalize chips                                    40,352,487 (8,774)
+  90:starting to load payload                          40,352,494 (6)
+  15:starting LZMA decompress (ignore for x86)         54,335,177 (13,982,683)
+  16:finished LZMA decompress (ignore for x86)         54,335,213 (35)
+  15:starting LZMA decompress (ignore for x86)         56,242,188 (1,906,975)
+  16:finished LZMA decompress (ignore for x86)         56,242,324 (136)
+  15:starting LZMA decompress (ignore for x86)         56,242,327 (2)
+  16:finished LZMA decompress (ignore for x86)         56,242,350 (23)
+  99:selfboot jump                                     57,809,271 (1,566,921)
+```
+
+Stock ASRock UEFI can be easily measured with systemd-analyze, though that's
+excluding PSP time, which should be the same as in coreboot:
+
+```text
+ubuntu@3mdeb:~$ sudo systemd-analyze
+[sudo] password for ubuntu:
+Startup finished in 2min 58.748s (firmware) + 1.126s (loader) + 539ms (kernel) + 10.353s (initrd) + 10.407s (userspace) = 3min 21.174s
+graphical.target reached after 10.402s in userspace.
+```
+
+Including time spent in PSP firmware, coreboot + LinuxBoot reduces the boot time
+from 3:27 to 57 seconds.
+
+## Support
+
+### Hardware support
+
+Hardware support is provided by [3mdeb](https://3mdeb.com/), and BenchRack units
+are available from the [3mdeb shop](https://shop.3mdeb.com/product/benchrack-asrock-turind8ud-2t-x550-with-dasharo-pro-package-for-servers/).
+
+### Community support
+
+* [Dasharo community](https://docs.dasharo.com/#community) — documentation and
+  matrix chat channels.
+* [LinuxBoot open source community](https://www.linuxboot.org/) — Slack, IRC,
+  mailing list, and regular meetings for technical questions.
+
+### Professional support
+
+Professional support services are provided by [3mdeb](https://3mdeb.com/).
+
+## See also
+
+* [Dasharo documentation](https://docs.dasharo.com/)
+* [Dasharo RTE specification](https://docs.dasharo.com/transparent-validation/rte/v1.1.0/specification/)

src/case_studies/index.md

@@ -7,3 +7,4 @@ This chapter contains case studies for various solutions.
 1. [Ampere study](Ampere_study.md)
 2. [Google study](Google_study.md)
 3. [OCP TiogaPass](TiogaPass.md)
+4. [Dasharo BenchRack ASRock TURIND8UD-2T/X550](DasharoBenchRack_study.md)