CV-Bowen opened a new pull request, #18259:
URL: https://github.com/apache/nuttx/pull/18259
## Summary
This PR adds comprehensive documentation for RPMsg diagnostic tools and
introduces priority support for RPMsg endpoints.
### Changes Overview
| Commit | Description |
|--------|-------------|
| `549fa726e1c` | Change virtqueue dump log level to emergency |
| `7890d5a534c` | Add rpmsg_ping documentation |
| `97d1d0ef455` | Add priority support for rpmsg endpoint |
| `455026a7a93` | Add rpmsg dump documentation |
## Motivation
1. **Documentation Gap**: The RPMsg subsystem lacked documentation for its
diagnostic tools (`rpmsg ping` and `rpmsg dump`), making it difficult for
developers to troubleshoot inter-processor communication issues.
2. **Debugging Visibility**: The virtqueue dump logs were using
`METAL_LOG_DEBUG` level, which could be filtered out in production builds,
making debugging difficult when issues occur.
3. **Priority Support**: Different RPMsg endpoints may have different
importance levels. Adding priority support allows for future scheduling
optimizations and better resource management.
## Changes
### 1. Documentation: RPMsg Ping (`rpmsg_ping.rst`)
Added comprehensive documentation for the RPMsg Ping diagnostic tool:
- Command syntax and parameters explanation
- Usage examples with sample output
- Architecture workflow diagram showing the complete ping process
- Best practices for latency and throughput testing
### 2. Documentation: RPMsg Dump (`rpmsg_dump.rst`)
Added detailed documentation for the RPMsg Dump command:
- Output format description (CPU info, endpoint list, virtqueue dump, buffer
states)
- Field-by-field explanation of dump output
- Common debugging use cases:
- TX buffer timeout issues
- Communication failures
- Buffer leak detection
### 3. OpenAMP Patch: Virtqueue Dump Log Level
Changed `virtqueue_dump()` log level from `METAL_LOG_DEBUG` to
`METAL_LOG_EMERGENCY` to ensure dump information is always visible when
debugging issues.
### 4. OpenAMP Patch: RPMsg Endpoint Priority
Added priority field to `struct rpmsg_endpoint`:
- Priority constants: `RPMSG_PRIO_MIN` (0), `RPMSG_PRIO_DEFAULT` (127),
`RPMSG_PRIO_MAX` (255)
- `RPMSG_PRIO_RT` alias for real-time priority
- Auto-initialization to default priority in `rpmsg_register_endpoint()`
## Files Changed
```
Documentation/components/drivers/special/rpmsg/index.rst | 2 +
Documentation/components/drivers/special/rpmsg/rpmsg_dump.rst | 199 +++
Documentation/components/drivers/special/rpmsg/rpmsg_ping.rst | 258
++++
openamp/0016-lib-virtio-virtqueue-change-the-virtqueue-dump-log-l.patch |
29 +
openamp/0017-lib-rpmsg-add-priority-support-for-rpmsg-endpoint.patch |
64 +
openamp/open-amp.cmake | 4 +
openamp/open-amp.defs | 2 +
```
## Impact
- **Stability**: No impact - documentation only changes and additive API
changes
- **Compatibility**: Fully backward compatible - priority field defaults to
127 if not explicitly set
- **Documentation**: Significantly improves developer experience for RPMsg
debugging
- **Breaking Changes**: None
## Testing
### Build Verification
```bash
# Configure and build for QEMU ARMv8-A
cmake -B cmake_out/v8a_server -DBOARD_CONFIG=qemu-armv8a:v8a_server -GNinja
cmake --build cmake_out/v8a_server
cmake -B cmake_out/v8a_proxy -DBOARD_CONFIG=qemu-armv8a:v8a_proxy -GNinja
cmake --build cmake_out/v8a_proxy
```
### Documentation Build
```bash
cd Documentation
make html
# Verify new .rst files render correctly
```
### Runtime Testing (QEMU Dual-Core)
**Test Environment:**
- Host: Linux x86_64
- Target: QEMU ARMv8-A (dual-core simulation)
- Configuration: `qemu-armv8a:v8a_server` + `qemu-armv8a:v8a_proxy`
Log
```c
server> rpmsg ping all 1 1 1 1
[ 0.000000] [ 7] [ EMERG] [server] ping times: 1
[ 0.000000] [ 7] [ EMERG] [server] buffer_len: 1520, send_len: 17
[ 0.000000] [ 7] [ EMERG] [server] avg: 0 s, 16954704 ns
[ 0.000000] [ 7] [ EMERG] [server] min: 0 s, 16954704 ns
[ 0.000000] [ 7] [ EMERG] [server] max: 0 s, 16954704 ns
[ 0.000000] [ 7] [ EMERG] [server] rate: 0.008021 Mbits/sec
[ 0.000000] [ 7] [ EMERG] [server] ping times: 1
[ 0.000000] [ 7] [ EMERG] [server] buffer_len: 2024, send_len: 17
[ 0.000000] [ 7] [ EMERG] [server] avg: 0 s, 16483360 ns
[ 0.000000] [ 7] [ EMERG] [server] min: 0 s, 16483360 ns
[ 0.000000] [ 7] [ EMERG] [server] max: 0 s, 16483360 ns
[ 0.000000] [ 7] [ EMERG] [server] rate: 0.008250 Mbits/sec
server>
server>
server> rpmsg dump all
[ 0.000000] [ 7] [ EMERG] [server] Local: server Remote: proxy Headrx 8
[ 0.000000] [ 7] [ EMERG] [server] Dump rpmsg info between cpu (master:
yes)server <==> proxy:
[ 0.000000] [ 7] [ EMERG] [server] rpmsg vq RX:
[ 0.000000] [ 7] [ EMERG] [server] VQ: rx_vq - size=8; free=0; queued=0;
desc_head_idx=32768; available_idx=0; avail.idx=16; used_cons_idx=8; used.idx1
[ 0.000000] [ 7] [ EMERG] [server] rpmsg vq TX:
[ 0.000000] [ 7] [ EMERG] [server] VQ: tx_vq - size=8; free=5; queued=0;
desc_head_idx=3; available_idx=0; avail.idx=6; used_cons_idx=3; used.idx=6; a0
[ 0.000000] [ 7] [ EMERG] [server] rpmsg ept list:
[ 0.000000] [ 7] [ EMERG] [server] ept NS
[ 0.000000] [ 7] [ EMERG] [server] ept rpmsg-sensor
[ 0.000000] [ 7] [ EMERG] [server] ept rpmsg-ping
[ 0.000000] [ 7] [ EMERG] [server] ept rpmsg-syslog
[ 0.000000] [ 7] [ EMERG] [server] rpmsg buffer list:
[ 0.000000] [ 7] [ EMERG] [server] RX buffer, total 8, pending 0
[ 0.000000] [ 7] [ EMERG] [server] TX buffer, total 8, pending 0
[ 0.000000] [ 7] [ EMERG] [server] Remote: proxy2 state: 1
[ 0.000000] [ 7] [ EMERG] [server] ept NS
[ 0.000000] [ 7] [ EMERG] [server] ept rpmsg-sensor
[ 0.000000] [ 7] [ EMERG] [server] ept rpmsg-ping
[ 0.000000] [ 7] [ EMERG] [server] rpmsg_port queue RX: {used: 0, avail:
8}
[ 0.000000] [ 7] [ EMERG] [server] rpmsg buffer list:
[ 0.000000] [ 7] [ EMERG] [server] rpmsg_port queue TX: {used: 0, avail:
8}
[ 0.000000] [ 7] [ EMERG] [server] rpmsg buffer list:
[ 0.000000] [ 7] [ ALERT] [server] sched_dumpstack: backtrace| 5:
0x00000000402a8500 0x00000000402aa1c4 0x000000004029bf78 0x000000004028ca54
0x0000004
[ 0.000000] [ 7] [ ALERT] [server] sched_dumpstack: backtrace| 5:
0x00000000402ace74
[ 0.000000] [ 7] [ ALERT] [server] sched_dumpstack: backtrace| 6:
0x00000000402a8920 0x00000000402f59a4 0x00000000402bbcb0 0x00000000402bce4c
0x0000004
server> uname -a
NuttX server 12.10.0 455026a7a93-dirty Jan 29 2026 16:27:05 arm64 qemu-armv8a
server>
```
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