Nouveau - Oct 2025 - [PATCH v4 12/13] nova-core: falcon: Add support to write firmware version

From: Joel Fernandes <joelagnelf at nvidia.com>

This will be needed by both the GSP boot code as well as GSP resume code
in the sequencer.

Signed-off-by: Joel Fernandes <joelagnelf at nvidia.com>
Reviewed-by: Lyude Paul <lyude at redhat.com>
---
 drivers/gpu/nova-core/falcon.rs | 9 +++++++++
 drivers/gpu/nova-core/regs.rs   | 6 ++++++
 2 files changed, 15 insertions(+)

diff --git a/drivers/gpu/nova-core/falcon.rs b/drivers/gpu/nova-core/falcon.rs
index 185ed6d1cfb8..01869b8deb8a 100644
--- a/drivers/gpu/nova-core/falcon.rs
+++ b/drivers/gpu/nova-core/falcon.rs
@@ -515,4 +515,13 @@ pub(crate) fn is_riscv_active(&self, bar: &Bar0)
-> bool {
         let cpuctl = regs::NV_PRISCV_RISCV_CPUCTL::read(bar, &E::ID);
         cpuctl.active_stat()
     }
+
+    /// Write the application version to the OS register.
+    #[expect(dead_code)]
+    pub(crate) fn write_os_version(&self, bar: &Bar0, app_version: u32)
-> Result<()> {
+        regs::NV_PFALCON_FALCON_OS::default()
+            .set_value(app_version)
+            .write(bar, &E::ID);
+        Ok(())
+    }
 }
diff --git a/drivers/gpu/nova-core/regs.rs b/drivers/gpu/nova-core/regs.rs
index 3bd1bddb16bb..6eda5c44c599 100644
--- a/drivers/gpu/nova-core/regs.rs
+++ b/drivers/gpu/nova-core/regs.rs
@@ -215,6 +215,12 @@ pub(crate) fn vga_workspace_addr(self) ->
Option<u64> {
     31:0    value as u32;
 });
 
+// Used to store version information about the firmware running
+// on the Falcon processor.
+register!(NV_PFALCON_FALCON_OS @ PFalconBase[0x00000080] {
+    31:0    value as u32;
+});
+
 register!(NV_PFALCON_FALCON_RM @ PFalconBase[0x00000084] {
     31:0    value as u32;
 });
-- 
2.50.1

On Wed, 2025-10-08 at 11:12 +1100, Alistair Popple
wrote:
> +
> +??? /// Write the application version to the OS register.
> +??? #[expect(dead_code)]
> +??? pub(crate) fn write_os_version(&self, bar: &Bar0, app_version:
u32) -> Result<()> {
> +??????? regs::NV_PFALCON_FALCON_OS::default()
> +??????????? .set_value(app_version)
> +??????????? .write(bar, &E::ID);
> +??????? Ok(())
> +??? }
I should have noticed this in v3, but why return Result here?  This is just like
is_riscv_active
-- this function cannot fail.