[PATCH v1 11/12] gpu: nova-core: mm: Add GpuMm centralized memory manager

[Joel Fernandes <joelagnelf@nvidia.com>]

Introduce GpuMm as the centralized GPU memory manager. At this point in
the series, GpuMm only owns the PRAMIN window for direct VRAM access;
the buddy allocator and TLB manager are added later when those backing
types become available.

This provides a clean ownership model where GpuMm provides accessor
methods for its components that can be used for memory management
operations, and lets follow-on patches (such as the PRAMIN aperture
self-tests) reference `self.mm.pramin()` cleanly.

Signed-off-by: Joel Fernandes <joelagnelf@nvidia.com>
---
 drivers/gpu/nova-core/gpu.rs | 22 +++++++++++++++++
 drivers/gpu/nova-core/mm.rs  | 46 ++++++++++++++++++++++++++++++++++--
 2 files changed, 66 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/nova-core/gpu.rs b/drivers/gpu/nova-core/gpu.rs
index d9d1a7417a2e..38544c38d660 100644
--- a/drivers/gpu/nova-core/gpu.rs
+++ b/drivers/gpu/nova-core/gpu.rs
@@ -25,6 +25,10 @@
         commands::GetGspStaticInfoReply,
         Gsp, //
     },
+    mm::{
+        GpuMm,
+        IntoVramRange, //
+    },
     regs,
 };
 
@@ -261,6 +265,8 @@ pub(crate) struct Gpu {
     gsp_falcon: Falcon<GspFalcon>,
     /// SEC2 falcon instance, used for GSP boot up and cleanup.
     sec2_falcon: Falcon<Sec2Falcon>,
+    /// GPU memory manager owning memory management resources.
+    mm: Arc<GpuMm>,
     /// GSP runtime data. Temporarily an empty placeholder.
     #[pin]
     gsp: Gsp,
@@ -306,6 +312,22 @@ pub(crate) fn new<'a>(
                     );
                 })?,
 
+            // Create GPU memory manager owning memory management resources.
+            mm: {
+                // PRAMIN covers all physical VRAM (including GSP-reserved areas
+                // above the usable region, e.g. the BAR1 page directory).
+                let pramin_vram_region = (0..gsp_static_info.total_fb_end).into_vram_range();
+                Arc::pin_init(
+                    GpuMm::new(
+                        devres_bar.clone(),
+                        pdev.as_ref(),
+                        spec.chipset,
+                        pramin_vram_region,
+                    )?,
+                    GFP_KERNEL,
+                )?
+            },
+
             bar: devres_bar,
         })
     }
diff --git a/drivers/gpu/nova-core/mm.rs b/drivers/gpu/nova-core/mm.rs
index f425467281d3..5c1941d20d1b 100644
--- a/drivers/gpu/nova-core/mm.rs
+++ b/drivers/gpu/nova-core/mm.rs
@@ -2,7 +2,7 @@
 
 //! Memory management subsystems for nova-core.
 
-#![expect(dead_code)]
+#![allow(dead_code)]
 
 /// Implements `From` conversions between a frame-number type and `Bounded<u64, N>`.
 ///
@@ -37,10 +37,52 @@ macro_rules! impl_pfn_bounded {
 
 use kernel::{
     bitfield,
+    device,
+    devres::Devres,
     num::Bounded,
-    prelude::*, //
+    prelude::*,
+    sync::Arc, //
 };
 
+use crate::{
+    driver::Bar0,
+    gpu::Chipset, //
+};
+
+/// GPU Memory Manager - owns all core MM components.
+///
+/// Provides centralized ownership of memory management resources:
+/// - [`pramin::Pramin`] for direct VRAM access.
+#[pin_data]
+pub(crate) struct GpuMm {
+    #[pin]
+    pramin: pramin::Pramin,
+}
+
+impl GpuMm {
+    /// Create a pin-initializer for `GpuMm`.
+    ///
+    /// `pramin_vram_region` is the full physical VRAM range (including GSP-reserved
+    /// areas). PRAMIN window accesses are validated against this range.
+    pub(crate) fn new(
+        bar: Arc<Devres<Bar0>>,
+        dev: &device::Device<device::Bound>,
+        chipset: Chipset,
+        pramin_vram_region: Range<VramAddress>,
+    ) -> Result<impl PinInit<Self>> {
+        let pramin_init = pramin::Pramin::new(bar, dev, chipset, pramin_vram_region)?;
+
+        Ok(pin_init!(Self {
+            pramin <- pramin_init,
+        }))
+    }
+
+    /// Access the [`pramin::Pramin`].
+    pub(crate) fn pramin(&self) -> &pramin::Pramin {
+        &self.pramin
+    }
+}
+
 bitfield! {
     /// Physical VRAM address in GPU video memory.
     pub(crate) struct VramAddress(u64) {
-- 
2.34.1