[PATCH 4/4] gpu: nova-core: gsp: Expose total physical VRAM end from FB region info

[Alexandre Courbot <acourbot@nvidia.com>]

From: 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             | 5 ++++-
 drivers/gpu/nova-core/gsp/commands.rs    | 5 +++++
 drivers/gpu/nova-core/gsp/fw/commands.rs | 7 +++++++
 3 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/nova-core/gpu.rs b/drivers/gpu/nova-core/gpu.rs
index a0cb36cdeeea..a357a5e60613 100644
--- a/drivers/gpu/nova-core/gpu.rs
+++ b/drivers/gpu/nova-core/gpu.rs
@@ -9,7 +9,8 @@
     io::Io,
     num::Bounded,
     pci,
-    prelude::*, //
+    prelude::*,
+    sizes::SizeConstants, //
 };
 
 use crate::{
@@ -368,6 +369,8 @@ pub(crate) fn new(
                     Err(e) => dev_warn!(pdev, "GPU name unavailable: {:?}\n", e),
                 }
 
+                dev_info!(pdev, "Total VRAM: {} MiB\n", info.total_fb_end / u64::SZ_1M);
+
                 info
             }
         })
diff --git a/drivers/gpu/nova-core/gsp/commands.rs b/drivers/gpu/nova-core/gsp/commands.rs
index d955f52a93bb..6623c7acf7cb 100644
--- a/drivers/gpu/nova-core/gsp/commands.rs
+++ b/drivers/gpu/nova-core/gsp/commands.rs
@@ -198,6 +198,8 @@ 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 {
@@ -209,9 +211,12 @@ 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.usable_fb_regions_iter().next().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 d025167927df..64154b487c05 100644
--- a/drivers/gpu/nova-core/gsp/fw/commands.rs
+++ b/drivers/gpu/nova-core/gsp/fw/commands.rs
@@ -167,6 +167,13 @@ pub(crate) fn usable_fb_regions_iter(&self) -> impl Iterator<Item = 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.

-- 
2.54.0