[PATCH v11 03/20] gpu: nova-core: gsp: Expose total physical VRAM end from FB region info

[Joel Fernandes]

Add `total_fb_end()` to `GspStaticConfigInfo` that computes the
exclusive end address of the highest valid FB region covering both
usable and GSP-reserved areas.

This allows callers to know the full physical VRAM extent, not just
the allocatable portion.

Signed-off-by: Joel Fernandes <joelagnelf@xxxxxxxxxx>
---
 drivers/gpu/nova-core/gsp/commands.rs    | 6 ++++++
 drivers/gpu/nova-core/gsp/fw/commands.rs | 7 +++++++
 2 files changed, 13 insertions(+)

diff --git a/drivers/gpu/nova-core/gsp/commands.rs b/drivers/gpu/nova-core/gsp/commands.rs
index d18abd8b5f04..e42a865fd4ac 100644
--- a/drivers/gpu/nova-core/gsp/commands.rs
+++ b/drivers/gpu/nova-core/gsp/commands.rs
@@ -196,6 +196,9 @@ pub(crate) struct GetGspStaticInfoReply {
     /// Usable FB (VRAM) region for driver memory allocation.
     #[expect(dead_code)]
     pub(crate) usable_fb_region: Range<u64>,
+    /// End of VRAM.
+    #[expect(dead_code)]
+    pub(crate) total_fb_end: u64,
 }
 
 impl MessageFromGsp for GetGspStaticInfoReply {
@@ -207,9 +210,12 @@ fn read(
         msg: &Self::Message,
         _sbuffer: &mut SBufferIter<array::IntoIter<&[u8], 2>>,
     ) -> Result<Self, Self::InitError> {
+        let total_fb_end = msg.total_fb_end().ok_or(ENODEV)?;
+
         Ok(GetGspStaticInfoReply {
             gpu_name: msg.gpu_name_str(),
             usable_fb_region: msg.first_usable_fb_region().ok_or(ENODEV)?,
+            total_fb_end,
         })
     }
 }
diff --git a/drivers/gpu/nova-core/gsp/fw/commands.rs b/drivers/gpu/nova-core/gsp/fw/commands.rs
index 3d5180e6b1e0..f2d59aa3131f 100644
--- a/drivers/gpu/nova-core/gsp/fw/commands.rs
+++ b/drivers/gpu/nova-core/gsp/fw/commands.rs
@@ -164,6 +164,13 @@ pub(crate) fn first_usable_fb_region(&self) -> Option<Range<u64>> {
             }
         })
     }
+
+    /// Compute the end of physical VRAM from all FB regions.
+    pub(crate) fn total_fb_end(&self) -> Option<u64> {
+        self.fb_regions()
+            .filter_map(|reg| reg.limit.checked_add(1))
+            .max()
+    }
 }
 
 // SAFETY: Padding is explicit and will not contain uninitialized data.
-- 
2.34.1