linux-kernel - [PATCH 5/7] gpu: nova-core: Add support for managing GSP falcon interrupts

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Message-Id: <20251020185539.49986-6-joelagnelf@nvidia.com>
Date: Mon, 20 Oct 2025 14:55:37 -0400
From: Joel Fernandes <joelagnelf@...dia.com>
To: linux-kernel@...r.kernel.org,
	rust-for-linux@...r.kernel.org,
	dri-devel@...ts.freedesktop.org,
	dakr@...nel.org,
	acourbot@...dia.com
Cc: Alistair Popple <apopple@...dia.com>,
	Miguel Ojeda <ojeda@...nel.org>,
	Alex Gaynor <alex.gaynor@...il.com>,
	Boqun Feng <boqun.feng@...il.com>,
	Gary Guo <gary@...yguo.net>,
	bjorn3_gh@...tonmail.com,
	Benno Lossin <lossin@...nel.org>,
	Andreas Hindborg <a.hindborg@...nel.org>,
	Alice Ryhl <aliceryhl@...gle.com>,
	Trevor Gross <tmgross@...ch.edu>,
	David Airlie <airlied@...il.com>,
	Simona Vetter <simona@...ll.ch>,
	Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
	Maxime Ripard <mripard@...nel.org>,
	Thomas Zimmermann <tzimmermann@...e.de>,
	John Hubbard <jhubbard@...dia.com>,
	Joel Fernandes <joelagnelf@...dia.com>,
	Timur Tabi <ttabi@...dia.com>,
	joel@...lfernandes.org,
	Elle Rhumsaa <elle@...thered-steel.dev>,
	Daniel Almeida <daniel.almeida@...labora.com>,
	nouveau@...ts.freedesktop.org
Subject: [PATCH 5/7] gpu: nova-core: Add support for managing GSP falcon interrupts

Add support for managing GSP falcon interrupts. These are required for
GSP message queue interrupt handling.

Also rename clear_swgen0_intr() to enable_msq_interrupt() for
readability.

Signed-off-by: Joel Fernandes <joelagnelf@...dia.com>
---
 drivers/gpu/nova-core/falcon/gsp.rs | 26 +++++++++++++++++++++++---
 drivers/gpu/nova-core/gpu.rs        |  2 +-
 drivers/gpu/nova-core/regs.rs       | 10 ++++++++++
 3 files changed, 34 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/nova-core/falcon/gsp.rs b/drivers/gpu/nova-core/falcon/gsp.rs
index f17599cb49fa..6da63823996b 100644
--- a/drivers/gpu/nova-core/falcon/gsp.rs
+++ b/drivers/gpu/nova-core/falcon/gsp.rs
@@ -22,11 +22,31 @@ impl FalconEngine for Gsp {
 }
 
 impl Falcon<Gsp> {
-    /// Clears the SWGEN0 bit in the Falcon's IRQ status clear register to
-    /// allow GSP to signal CPU for processing new messages in message queue.
-    pub(crate) fn clear_swgen0_intr(&self, bar: &Bar0) {
+    /// Enable the GSP Falcon message queue interrupt (SWGEN0 interrupt).
+    #[expect(dead_code)]
+    pub(crate) fn enable_msgq_interrupt(&self, bar: &Bar0) {
+        regs::NV_PFALCON_FALCON_IRQMASK::alter(bar, &Gsp::ID, |r| r.set_swgen0(true));
+    }
+
+    /// Check if the message queue interrupt is pending.
+    #[expect(dead_code)]
+    pub(crate) fn has_msgq_interrupt(&self, bar: &Bar0) -> bool {
+        regs::NV_PFALCON_FALCON_IRQSTAT::read(bar, &Gsp::ID).swgen0()
+    }
+
+    /// Clears the message queue interrupt to allow GSP to signal CPU
+    /// for processing new messages.
+    pub(crate) fn clear_msgq_interrupt(&self, bar: &Bar0) {
         regs::NV_PFALCON_FALCON_IRQSCLR::default()
             .set_swgen0(true)
             .write(bar, &Gsp::ID);
     }
+
+    /// Acknowledge all pending GSP interrupts.
+    #[expect(dead_code)]
+    pub(crate) fn ack_all_interrupts(&self, bar: &Bar0) {
+        // Read status and write the raw value to IRQSCLR to clear all pending interrupts.
+        let status = regs::NV_PFALCON_FALCON_IRQSTAT::read(bar, &Gsp::ID);
+        regs::NV_PFALCON_FALCON_IRQSCLR::from(u32::from(status)).write(bar, &Gsp::ID);
+    }
 }
diff --git a/drivers/gpu/nova-core/gpu.rs b/drivers/gpu/nova-core/gpu.rs
index af20e2daea24..fb120cf7b15d 100644
--- a/drivers/gpu/nova-core/gpu.rs
+++ b/drivers/gpu/nova-core/gpu.rs
@@ -216,7 +216,7 @@ pub(crate) fn new<'a>(
                 bar,
                 spec.chipset > Chipset::GA100,
             )
-            .inspect(|falcon| falcon.clear_swgen0_intr(bar))?,
+            .inspect(|falcon| falcon.clear_msgq_interrupt(bar))?,
 
             sec2_falcon: Falcon::new(pdev.as_ref(), spec.chipset, bar, true)?,
 
diff --git a/drivers/gpu/nova-core/regs.rs b/drivers/gpu/nova-core/regs.rs
index 206dab2e1335..a3836a01996b 100644
--- a/drivers/gpu/nova-core/regs.rs
+++ b/drivers/gpu/nova-core/regs.rs
@@ -198,6 +198,16 @@ pub(crate) fn vga_workspace_addr(self) -> Option<u64> {
 
 // PFALCON
 
+register!(NV_PFALCON_FALCON_IRQMASK @ PFalconBase[0x00000014] {
+    4:4     halt as bool;
+    6:6     swgen0 as bool;
+});
+
+register!(NV_PFALCON_FALCON_IRQSTAT @ PFalconBase[0x00000008] {
+    4:4     halt as bool;
+    6:6     swgen0 as bool;
+});
+
 register!(NV_PFALCON_FALCON_IRQSCLR @ PFalconBase[0x00000004] {
     4:4     halt as bool;
     6:6     swgen0 as bool;
-- 
2.34.1