[PATCH v12 03/22] gpu: nova-core: gsp: Expose total physical VRAM end from FB region info

[Joel Fernandes <joelagnelf@nvidia.com>]

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@nvidia.com>
---
 drivers/gpu/nova-core/gpu.rs             | 12 +++++++++++-
 drivers/gpu/nova-core/gsp/commands.rs    |  5 +++++
 drivers/gpu/nova-core/gsp/fw/commands.rs |  7 +++++++
 3 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/nova-core/gpu.rs b/drivers/gpu/nova-core/gpu.rs
index f2a8915a1ff4..675a0676f032 100644
--- a/drivers/gpu/nova-core/gpu.rs
+++ b/drivers/gpu/nova-core/gpu.rs
@@ -273,7 +273,17 @@ pub(crate) fn new<'a>(
 
             gsp <- Gsp::new(pdev),
 
-            gsp_static_info: { gsp.boot(pdev, bar, spec.chipset, gsp_falcon, sec2_falcon)? },
+            gsp_static_info: {
+                let info = gsp.boot(pdev, bar, spec.chipset, gsp_falcon, sec2_falcon)?;
+
+                dev_info!(
+                    pdev.as_ref(),
+                    "Total physical VRAM: {} MiB\n",
+                    info.total_fb_end >> 20
+                );
+
+                info
+            },
 
             bar: devres_bar,
         })
diff --git a/drivers/gpu/nova-core/gsp/commands.rs b/drivers/gpu/nova-core/gsp/commands.rs
index d18abd8b5f04..40b4ef72169d 100644
--- a/drivers/gpu/nova-core/gsp/commands.rs
+++ b/drivers/gpu/nova-core/gsp/commands.rs
@@ -196,6 +196,8 @@ 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.
+    pub(crate) total_fb_end: u64,
 }
 
 impl MessageFromGsp for GetGspStaticInfoReply {
@@ -207,9 +209,12 @@ 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 a34d29280430..8619f08a689d 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