Fix stm32f723disco host HIL: UART RX starvation + DWC2 split bulk NAK/XactErr handling (#3677)
stm32f7 BSP — UART RX starvation
- The host console USART shared interrupt priority with the USB OTG ISR, so a long
OTG interrupt could starve RXNE and drop received bytes. Raise the USART RX IRQ
above OTG_FS/OTG_HS in both the bare-metal and FreeRTOS init paths, guarded by
#ifdef UART_ID so boards without a UART console keep the default OTG priority.
dwc2 host — split NAK/XactErr handling
- Slave mode: a persistently-NAKing split bulk/control IN poll re-armed the
start-split immediately, storming the ISR and starving task context. Throttle by
disabling the channel and re-arming on the resulting halt (no frame deferral).
- Buffer-DMA mode: a pure split bulk-OUT NAK was unhandled, leaving the channel
halted and stalling the transfer — the dominant cause of CDC echo truncation.
Handle it by rewinding the buffer pointers and retrying the start-split
(Programming Guide v4.20a 5.1.4.2).
- Buffer-DMA mode: a split bulk-OUT XactErr was retried immediately, exhausting
HCD_XFER_ERROR_MAX before the transient cleared. Throttle via channel_disable +
re-arm to give the hub TT a recovery gap, mirroring slave mode.
- All three are scoped to split transfers (hcsplt.split_en); non-split NAK/XactErr
keep the core-handled / immediate-retry behavior. The OUT XactErr throttle also
excludes periodic split, where channel_disable() is a no-op and would wedge the
channel. The nak_disabled flag is generalized to retry_disabled and honors
xfer->closing so an endpoint close during a throttled retry tears down cleanly.
Verified on stm32f723disco HIL (slave + CFG_TUH_DWC2_DMA_ENABLE): host/cdc_msc_hid,
msc_file_explorer, and device_info all pass on both variants; DMA CDC echo went
from ~15-25% raw failure to 10/10 clean.
- Introduced a `code-size` skill under `.claude/skills` for evaluating TinyUSB code size changes between the base branch and current branch.
- Added `metrics_compare_base.py`, automating code size comparison with granular options for examples, boards, and CI-wide runs.
- Updated `AGENTS.md` to include quick references and usage guidance for the new feature.
AGENTS.md:
- fix build dir to cmake-build-<board> (matches hil_test.py expectation)
- reformat flash section to avoid shell-pipe ambiguity, use <board>
- mention board.mk for Make-based builds
- complete OpenOCD jlink interface example
- update stale "Build Option 2" references to "All examples for a board"
- split PVS-Studio command so it is copy-pasteable
.claude/skills/hil/SKILL.md:
- clarify local.json is user-supplied, not tracked in repo
- use python3 consistently
- add all-boards variant for remote execution
- delegate remote execution to test/hil/hil_ci.sh
test/hil/hil_ci.sh:
- portable shebang (/usr/bin/env bash)
- set -euo pipefail
- env overrides for REMOTE, REMOTE_DIR, CONFIG, ROOT_DIR
- --prune-empty-dirs on rsync to skip empty subdirs
- fail-fast sanity check on repo layout
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
