Notes on supported platforms

platform/README.md

@@ -4,7 +4,16 @@ Currently supported platforms:
 
 | Platform | Legacy | Base | IPI | Timer | RFENCE | HSM | SRST | Note |
 |:---------|:------:|:----:|:---:|:-----:|:------:|:---:|:----:|:-----|
-| [Kendryte K210](./k210) | √ | √ | √ | √ | P | P | P | Privileged spec version: 1.9.1 | 
-| [QEMU](./qemu)          | √ | √ | √ | √ | P | P | √ | - | 
+| [Kendryte K210](./k210) | √ | √ | √ | √ | P | P | P | Privileged spec version: 1.9.1 |
+| [QEMU](./qemu)          | √ | √ | √ | √ | P | P | √ | - |
 
 P: Pending
+
+## Notes
+
+These platforms implementations are only for reference.
+Although binaries are released along with RustSBI library itself,
+platform developers should consider using RustSBI as a library,
+other than adding code into forked project's 'platforms' and make a pull request.
+
+A reference platform implementation using RustSBI can be found at [shady831213/terminus_bl](https://github.com/shady831213/terminus_bl).