Claude review: gpu: nova-core: gsp: add sync and async command queue API to `Cmdq`

[Claude Code Review Bot <claude-review@example.com>]

Patch Review

This is the core type infrastructure patch. Key observations:

**The `NoReply` marker type is well-designed:**
```rust
pub(crate) struct NoReply;
```
Not implementing `MessageFromGsp` means `send_sync_command` can't be called with async commands — the compiler enforces it via `M::Reply: MessageFromGsp`.

**Associated type on `CommandToGsp`:**
```rust
type Reply;
```
Clean addition. The cover letter discusses the alternative of separate `SyncCommand`/`AsyncCommand` traits, and I agree the associated type approach is more composable.

**`send_sync_command` implementation:**
```rust
pub(crate) fn send_sync_command<M>(&mut self, bar: &Bar0, command: M) -> Result<M::Reply>
{
    self.send_command(bar, command)?;

    loop {
        match self.receive_msg::<M::Reply>(Delta::from_secs(10)) {
            Ok(reply) => break Ok(reply),
            Err(ERANGE) => continue,
            Err(e) => break Err(e),
        }
    }
}
```
This correctly extracts the existing pattern from `get_gsp_info`. Note the timeout change from 5s to 10s as mentioned above — this is fine but worth acknowledging.

**`send_async_command` is a thin wrapper:**
```rust
pub(crate) fn send_async_command<M>(&mut self, bar: &Bar0, command: M) -> Result
where
    M: CommandToGsp<Reply = NoReply>,
{
    self.send_command(bar, command)
}
```
The `Reply = NoReply` constraint is the enforcement mechanism. Clean.

**Making `send_command` private (`fn` instead of `pub(crate) fn`):**
```rust
-    pub(crate) fn send_command<M>(&mut self, bar: &Bar0, command: M) -> Result
+    fn send_command<M>(&mut self, bar: &Bar0, command: M) -> Result
```
Good — callers should now go through the sync/async API.

**`SplitCommand` propagates `Reply`:**
```rust
+    type Reply = C::Reply;
```
Correct — a split command should have the same reply type as the underlying command.

**Caller updates in boot.rs:**
```rust
-            .send_command(bar, commands::SetSystemInfo::new(pdev))?;
+            .send_async_command(bar, commands::SetSystemInfo::new(pdev))?;
```
Correct — these pre-boot commands are fire-and-forget.

**Refactoring of `get_gsp_info`:**
```rust
-    cmdq.send_command(bar, GetGspStaticInfo)?;
-    loop {
-        match cmdq.receive_msg::<GetGspStaticInfoReply>(Delta::from_secs(5)) {
-            Ok(info) => return Ok(info),
-            Err(ERANGE) => continue,
-            Err(e) => return Err(e),
-        }
-    }
+    cmdq.send_sync_command(bar, GetGspStaticInfo)
```
Nice simplification.

No issues. **Reviewed-by worthy.**

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Generated by Claude Code Patch Reviewer