Claude review: gpu: drm: nova: build after nova-core metadata

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

Patch Review

**Verdict: Functional but has the recursive make caveat.**

```makefile
$(objtree)/$(nova_core_rmeta): FORCE
	$(Q)$(MAKE) $(build)=drivers/gpu/nova-core $(nova_core_rmeta)
```

This recursive make invocation is the "ugly but temporary" part the comments acknowledge. It works, but:

1. **Recursive make breaks dependency tracking**: The top-level make can't see into the sub-make's dependency graph. If `nova_core.rs` changes, the sub-make will rebuild the rmeta, but the parent make's timestamp-based tracking may not always re-trigger correctly since the target is `FORCE`-ed anyway.

2. **Order-only dependency** on `nova.o`:
```makefile
$(obj)/nova.o: | $(objtree)/$(nova_core_rmeta)
```
The `|` (order-only) prerequisite means make won't rebuild `nova.o` when the rmeta *content* changes, only ensures it exists before first compile. This seems intentional — rustc will detect stale metadata itself — but could lead to missed rebuilds if the rmeta format changes across rustc versions. For a temporary workaround, acceptable.

3. The `rustflags-y += --extern nova_core=$(objtree)/$(nova_core_rmeta)` path construction looks correct.

### PATCH 7 (POC): drm: nova: demonstrate interaction with nova-core

**Verdict: POC only, not for merge — review for completeness.**

This patch demonstrates the cross-module call by adding a `NovaCore::chipset()` method and calling it from `nova-drm`:

```rust
impl NovaCore {
    pub fn chipset(adev: &auxiliary::Device<Core>) -> Result<gpu::Chipset> {
        let dev = adev.parent();
        let drvdata = dev.drvdata::<Self>()?;
        Ok(drvdata.gpu.spec.chipset)
    }
}
```

Observations:

1. **API design**: The method takes an `auxiliary::Device<Core>` and navigates up to the parent PCI device to extract `drvdata`. This means the caller (`nova-drm`) needs to know that `nova-core`'s data lives on the parent device, which leaks implementation detail. A proper API would likely take `&self` or use a handle/trait abstraction. Fine for POC.

2. **Visibility changes**: `pub(crate)` to `pub` on `NovaCore`, `Chipset`, `Spec.chipset`, `Gpu.spec`, plus `mod driver`/`mod gpu` going from `mod` to `pub mod`. This opens up a lot of internal surface. The real implementation should expose a curated public API, not just broaden all visibility.

3. **The `#[allow(missing_docs)]` on `Chipset`** and the added `//!` module-level docs are there to satisfy clippy. Harmless but indicates the POC is lightly polished.

4. The trailing `//` comment on the import:
```rust
use crate::gpu::{
    self,
    Gpu, //
};
```
This is the `rustfmt` workaround pattern to force vertical formatting. Stylistically fine.

5. The `use nova_core::driver::NovaCore;` import in `nova-drm`'s `driver.rs` confirms the cross-crate resolution works via the `--extern` flag from patch 6.

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Generated by Claude Code Patch Reviewer