[PATCH 14/16] gpu: nova-core: Add BAR1 aperture type and size constant

[Eliot Courtney]

From: Joel Fernandes <joelagnelf@xxxxxxxxxx>

Add BAR1_SIZE constant and Bar1 type alias for the 256MB BAR1 aperture.
These are prerequisites for BAR1 memory access functionality.

Co-developed-by: Zhi Wang <zhiw@xxxxxxxxxx>
Signed-off-by: Zhi Wang <zhiw@xxxxxxxxxx>
Signed-off-by: Joel Fernandes <joelagnelf@xxxxxxxxxx>
[ecourtney: add the Bar1 lifetime for current PCI BAR ownership]
Signed-off-by: Eliot Courtney <ecourtney@xxxxxxxxxx>
---
 drivers/gpu/nova-core/driver.rs          | 2 ++
 drivers/gpu/nova-core/gsp/commands.rs    | 4 ++++
 drivers/gpu/nova-core/gsp/fw/commands.rs | 8 ++++++++
 3 files changed, 14 insertions(+)

diff --git a/drivers/gpu/nova-core/driver.rs b/drivers/gpu/nova-core/driver.rs
index 8cef4c284277..5723ff8f71ea 100644
--- a/drivers/gpu/nova-core/driver.rs
+++ b/drivers/gpu/nova-core/driver.rs
@@ -38,6 +38,8 @@ pub(crate) struct NovaCore<'bound> {
 
 pub(crate) type Bar0<'a> = &'a pci::Bar<'a, BAR0_SIZE>;
 pub(crate) type NovaRegisters = kernel::io::Region<BAR0_SIZE>;
+#[expect(dead_code)]
+pub(crate) type Bar1<'a> = pci::Bar<'a>;
 
 kernel::pci_device_table!(
     PCI_TABLE,
diff --git a/drivers/gpu/nova-core/gsp/commands.rs b/drivers/gpu/nova-core/gsp/commands.rs
index eea1c9ed4684..1c467718c679 100644
--- a/drivers/gpu/nova-core/gsp/commands.rs
+++ b/drivers/gpu/nova-core/gsp/commands.rs
@@ -214,6 +214,9 @@ fn init(&self) -> impl Init<Self::Command, Self::InitError> {
 /// The reply from the GSP to the [`GetGspStaticInfo`] command.
 pub(crate) struct GetGspStaticInfoReply {
     gpu_name: [u8; 64],
+    /// BAR1 Page Directory Entry base address.
+    #[expect(dead_code)]
+    pub(crate) bar1_pde_base: u64,
     /// Usable FB (VRAM) regions for driver memory allocation.
     pub(crate) usable_fb_regions: KVec<Range<u64>>,
     /// Exclusive end of the FB physical address space.
@@ -237,6 +240,7 @@ fn read(
 
         Ok(GetGspStaticInfoReply {
             gpu_name: msg.gpu_name_str(),
+            bar1_pde_base: msg.bar1_pde_base(),
             usable_fb_regions,
             total_fb_end,
         })
diff --git a/drivers/gpu/nova-core/gsp/fw/commands.rs b/drivers/gpu/nova-core/gsp/fw/commands.rs
index 6e85442a4b13..32856ff74183 100644
--- a/drivers/gpu/nova-core/gsp/fw/commands.rs
+++ b/drivers/gpu/nova-core/gsp/fw/commands.rs
@@ -131,6 +131,14 @@ impl GspStaticConfigInfo {
         self.0.gpuNameString
     }
 
+    /// Returns the BAR1 Page Directory Entry base address.
+    ///
+    /// This is the root page table address for BAR1 virtual memory,
+    /// set up by GSP-RM firmware.
+    pub(crate) fn bar1_pde_base(&self) -> u64 {
+        self.0.bar1PdeBase
+    }
+
     /// Returns an iterator over valid FB regions from GSP firmware data.
     fn fb_regions(
         &self,

-- 
2.55.0