[PATCH] Documentation: riscv: add patch acceptance guidelines

[Paul Walmsley]

Formalize, in kernel documentation, the patch acceptance policy for 
arch/riscv.  In summary, it states that as maintainers, we plan to only 
accept patches for new modules or extensions that have been frozen or 
ratified by the RISC-V Foundation.

We've been following these guidelines for the past few months.  In the
meantime, we've received quite a bit of feedback that it would be
helpful to have these guidelines formally documented.

Signed-off-by: Paul Walmsley <paul.walmsley@xxxxxxxxxx>
Cc: Palmer Dabbelt <palmer@xxxxxxxxxxx>
Cc: Albert Ou <aou@xxxxxxxxxxxxxxxxx>
Cc: Krste Asanovic <krste@xxxxxxxxxxxx>
Cc: Andrew Waterman <waterman@xxxxxxxxxxxxxxxxx>
---
 Documentation/riscv/patch-acceptance.rst | 32 ++++++++++++++++++++++++
 1 file changed, 32 insertions(+)
 create mode 100644 Documentation/riscv/patch-acceptance.rst

diff --git a/Documentation/riscv/patch-acceptance.rst b/Documentation/riscv/patch-acceptance.rst
new file mode 100644
index 000000000000..2e658353b53c
--- /dev/null
+++ b/Documentation/riscv/patch-acceptance.rst
@@ -0,0 +1,32 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+====================================================
+arch/riscv maintenance and the RISC-V specifications
+====================================================
+
+The RISC-V instruction set architecture is developed in the open:
+in-progress drafts are available for all to review and to experiment
+with implementations.  New module or extension drafts can change
+during the development process - sometimes in ways that are
+incompatible with previous drafts.  This flexibility can present a
+challenge for RISC-V Linux maintenance.  Linux maintainers disapprove
+of churn, and the Linux development process prefers well-reviewed and
+tested code over experimental code.  We wish to extend these same
+principles to the RISC-V-related code that will be accepted for
+inclusion in the kernel.
+
+Therefore, as maintainers, we'll only accept patches for new modules
+or extensions if the specifications for those modules or extensions
+are listed as being "Frozen" or "Ratified" by the RISC-V Foundation.
+(Developers may, of course, maintain their own Linux kernel trees that
+contain code for any draft extensions that they wish.)
+
+Additionally, the RISC-V specification allows implementors to create
+their own custom extensions.  These custom extensions aren't required
+to go through any review or ratification process by the RISC-V
+Foundation.  To avoid the maintenance complexity and potential
+performance impact of adding kernel code for implementor-specific
+RISC-V extensions, we'll only to accept patches for extensions that
+have been officially frozen or ratified by the RISC-V Foundation.
+(Implementors, may, of course, maintain their own Linux kernel trees
+containing code for any custom extensions that they wish.)
-- 
2.24.0.rc0