gpu: nova-core: gsp: Create rmargs

Initialise the GSP resource manager arguments (rmargs) which provides
initialisation parameters to the GSP firmware during boot. The rmargs
structure contains arguments to configure the GSP message/command queue
location.

These are mapped for coherent DMA and added to the libos data structure
for access when booting GSP.

Signed-off-by: Alistair Popple <apopple@nvidia.com>
Co-developed-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
Message-ID: <20251110-gsp_boot-v9-10-8ae4058e3c0e@nvidia.com>

drivers/gpu/nova-core/gsp.rs

@@ -24,8 +24,11 @@ pub(crate) use fw::{
 
 use crate::{
     gsp::cmdq::Cmdq,
-    gsp::fw::LibosMemoryRegionInitArgument,
-    num, //
+    gsp::fw::{
+        GspArgumentsCached,
+        LibosMemoryRegionInitArgument, //
+    },
+    num,
 };
 
 pub(crate) const GSP_PAGE_SHIFT: usize = 12;
@@ -108,6 +111,8 @@ pub(crate) struct Gsp {
     logrm: LogBuffer,
     /// Command queue.
     pub(crate) cmdq: Cmdq,
+    /// RM arguments.
+    rmargs: CoherentAllocation<GspArgumentsCached>,
 }
 
 impl Gsp {
@@ -134,11 +139,20 @@ impl Gsp {
 
         let cmdq = Cmdq::new(dev)?;
 
+        let rmargs = CoherentAllocation::<GspArgumentsCached>::alloc_coherent(
+            dev,
+            1,
+            GFP_KERNEL | __GFP_ZERO,
+        )?;
+        dma_write!(rmargs[0] = fw::GspArgumentsCached::new(&cmdq))?;
+        dma_write!(libos[3] = LibosMemoryRegionInitArgument::new("RMARGS", &rmargs))?;
+
         Ok(try_pin_init!(Self {
             libos,
             loginit,
             logintr,
             logrm,
+            rmargs,
             cmdq,
         }))
     }

drivers/gpu/nova-core/gsp/cmdq.rs

@@ -11,7 +11,10 @@ use core::{
 
 use kernel::{
     device,
-    dma::CoherentAllocation,
+    dma::{
+        CoherentAllocation,
+        DmaAddress, //
+    },
     dma_write,
     io::poll::read_poll_timeout,
     prelude::*,
@@ -33,6 +36,7 @@ use crate::{
             MsgqTxHeader, //
         },
         PteArray,
+        GSP_PAGE_SHIFT,
         GSP_PAGE_SIZE, //
     },
     num,
@@ -429,6 +433,22 @@ pub(crate) struct Cmdq {
 }
 
 impl Cmdq {
+    /// Offset of the data after the PTEs.
+    const POST_PTE_OFFSET: usize = core::mem::offset_of!(GspMem, cpuq);
+
+    /// Offset of command queue ring buffer.
+    pub(crate) const CMDQ_OFFSET: usize = core::mem::offset_of!(GspMem, cpuq)
+        + core::mem::offset_of!(Msgq, msgq)
+        - Self::POST_PTE_OFFSET;
+
+    /// Offset of message queue ring buffer.
+    pub(crate) const STATQ_OFFSET: usize = core::mem::offset_of!(GspMem, gspq)
+        + core::mem::offset_of!(Msgq, msgq)
+        - Self::POST_PTE_OFFSET;
+
+    /// Number of page table entries for the GSP shared region.
+    pub(crate) const NUM_PTES: usize = size_of::<GspMem>() >> GSP_PAGE_SHIFT;
+
     /// Creates a new command queue for `dev`.
     pub(crate) fn new(dev: &device::Device<device::Bound>) -> Result<Cmdq> {
         let gsp_mem = DmaGspMem::new(dev)?;
@@ -653,4 +673,9 @@ impl Cmdq {
 
         result
     }
+
+    /// Returns the DMA handle of the command queue's shared memory region.
+    pub(crate) fn dma_handle(&self) -> DmaAddress {
+        self.gsp_mem.0.dma_handle()
+    }
 }

drivers/gpu/nova-core/gsp/fw.rs

@@ -31,7 +31,10 @@ use crate::{
     fb::FbLayout,
     firmware::gsp::GspFirmware,
     gpu::Chipset,
-    gsp::GSP_PAGE_SIZE,
+    gsp::{
+        cmdq::Cmdq, //
+        GSP_PAGE_SIZE,
+    },
     num::{
         self,
         FromSafeCast, //
@@ -568,3 +571,42 @@ unsafe impl AsBytes for GspMsgElement {}
 // SAFETY: This struct only contains integer types for which all bit patterns
 // are valid.
 unsafe impl FromBytes for GspMsgElement {}
+
+/// Arguments for GSP startup.
+#[repr(transparent)]
+pub(crate) struct GspArgumentsCached(bindings::GSP_ARGUMENTS_CACHED);
+
+impl GspArgumentsCached {
+    /// Creates the arguments for starting the GSP up using `cmdq` as its command queue.
+    pub(crate) fn new(cmdq: &Cmdq) -> Self {
+        Self(bindings::GSP_ARGUMENTS_CACHED {
+            messageQueueInitArguments: MessageQueueInitArguments::new(cmdq).0,
+            bDmemStack: 1,
+            ..Default::default()
+        })
+    }
+}
+
+// SAFETY: Padding is explicit and will not contain uninitialized data.
+unsafe impl AsBytes for GspArgumentsCached {}
+
+// SAFETY: This struct only contains integer types for which all bit patterns
+// are valid.
+unsafe impl FromBytes for GspArgumentsCached {}
+
+/// Init arguments for the message queue.
+#[repr(transparent)]
+struct MessageQueueInitArguments(bindings::MESSAGE_QUEUE_INIT_ARGUMENTS);
+
+impl MessageQueueInitArguments {
+    /// Creates a new init arguments structure for `cmdq`.
+    fn new(cmdq: &Cmdq) -> Self {
+        Self(bindings::MESSAGE_QUEUE_INIT_ARGUMENTS {
+            sharedMemPhysAddr: cmdq.dma_handle(),
+            pageTableEntryCount: num::usize_into_u32::<{ Cmdq::NUM_PTES }>(),
+            cmdQueueOffset: num::usize_as_u64(Cmdq::CMDQ_OFFSET),
+            statQueueOffset: num::usize_as_u64(Cmdq::STATQ_OFFSET),
+            ..Default::default()
+        })
+    }
+}