[PATCH v2 09/13] gpu: nova-core: add Falcon HAL method supports_dma()

[Timur Tabi <ttabi@nvidia.com>]

Some GPUs do not support using DMA to transfer code/data from system
memory to Falcon memory, and instead must use programmed I/O (PIO).
Add a function to the Falcon HAL to indicate whether a given GPU's
Falcons support DMA for this purpose.

Signed-off-by: Timur Tabi <ttabi@nvidia.com>
---
 drivers/gpu/nova-core/falcon.rs           | 7 +++++++
 drivers/gpu/nova-core/falcon/hal.rs       | 3 +++
 drivers/gpu/nova-core/falcon/hal/ga102.rs | 4 ++++
 drivers/gpu/nova-core/falcon/hal/tu102.rs | 4 ++++
 4 files changed, 18 insertions(+)

diff --git a/drivers/gpu/nova-core/falcon.rs b/drivers/gpu/nova-core/falcon.rs
index f2da6a4a9d36..2770d608a2cf 100644
--- a/drivers/gpu/nova-core/falcon.rs
+++ b/drivers/gpu/nova-core/falcon.rs
@@ -631,6 +631,13 @@ pub(crate) fn is_riscv_active(&self, bar: &Bar0) -> bool {
         self.hal.is_riscv_active(bar)
     }
 
+    /// Check if this Falcon supports DMA for loading firmware.
+    ///
+    /// Returns `true` if DMA is supported, `false` if PIO must be used instead.
+    pub(crate) fn supports_dma(&self) -> bool {
+        self.hal.supports_dma()
+    }
+
     /// Write the application version to the OS register.
     pub(crate) fn write_os_version(&self, bar: &Bar0, app_version: u32) {
         regs::NV_PFALCON_FALCON_OS::default()
diff --git a/drivers/gpu/nova-core/falcon/hal.rs b/drivers/gpu/nova-core/falcon/hal.rs
index 7a6610e9d0a8..a760620221c3 100644
--- a/drivers/gpu/nova-core/falcon/hal.rs
+++ b/drivers/gpu/nova-core/falcon/hal.rs
@@ -48,6 +48,9 @@ fn signature_reg_fuse_version(
 
     /// Reset the falcon engine.
     fn reset_eng(&self, bar: &Bar0) -> Result;
+
+    /// Returns true of this Falcon supports DMA transfer from system memory to Falcon memory
+    fn supports_dma(&self) -> bool;
 }
 
 /// Returns a boxed falcon HAL adequate for `chipset`.
diff --git a/drivers/gpu/nova-core/falcon/hal/ga102.rs b/drivers/gpu/nova-core/falcon/hal/ga102.rs
index 232d51a4921f..684ca72b7cfe 100644
--- a/drivers/gpu/nova-core/falcon/hal/ga102.rs
+++ b/drivers/gpu/nova-core/falcon/hal/ga102.rs
@@ -160,4 +160,8 @@ fn reset_eng(&self, bar: &Bar0) -> Result {
 
         Ok(())
     }
+
+    fn supports_dma(&self) -> bool {
+        true
+    }
 }
diff --git a/drivers/gpu/nova-core/falcon/hal/tu102.rs b/drivers/gpu/nova-core/falcon/hal/tu102.rs
index 19a8b49ca2cd..d8ec914bd3f8 100644
--- a/drivers/gpu/nova-core/falcon/hal/tu102.rs
+++ b/drivers/gpu/nova-core/falcon/hal/tu102.rs
@@ -71,4 +71,8 @@ fn reset_eng(&self, bar: &Bar0) -> Result {
 
         Ok(())
     }
+
+    fn supports_dma(&self) -> bool {
+        false
+    }
 }
-- 
2.52.0