[PATCH v5 06/11] drm: nova: Add usable VRAM size to GPU info

[Alistair Popple <apopple@nvidia.com>]

Add a field to the GPU info struct containing the total usable
framebuffer size. The usable framebuffer excludes GSP carveouts and
other protected regions, so it may differ from the BAR size and total
physical VRAM.

Signed-off-by: Alistair Popple <apopple@nvidia.com>

---

Changes since v3:

 - Partially new for v4 - previously a separate scalar GETPARAM
   parameter
---
 drivers/gpu/drm/nova/file.rs          | 1 +
 drivers/gpu/nova-core/api.rs          | 5 +++++
 drivers/gpu/nova-core/gpu.rs          | 6 ++----
 drivers/gpu/nova-core/gsp/commands.rs | 8 ++++++++
 include/uapi/drm/nova_drm.h           | 6 ++++++
 5 files changed, 22 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/nova/file.rs b/drivers/gpu/drm/nova/file.rs
index 097bf607485c..cd80c5402eba 100644
--- a/drivers/gpu/drm/nova/file.rs
+++ b/drivers/gpu/drm/nova/file.rs
@@ -38,6 +38,7 @@ fn new(reg_data: &DrmRegData<'_>) -> Self {
         Self(uapi::drm_nova_gpu_info {
             architecture: reg_data.api.architecture(),
             implementation: reg_data.api.implementation(),
+            vram_size: reg_data.api.vram_size(),
         })
     }
 }
diff --git a/drivers/gpu/nova-core/api.rs b/drivers/gpu/nova-core/api.rs
index cff730a38c1d..1e73d27d701c 100644
--- a/drivers/gpu/nova-core/api.rs
+++ b/drivers/gpu/nova-core/api.rs
@@ -37,4 +37,9 @@ pub fn architecture(&self) -> u32 {
     pub fn implementation(&self) -> u32 {
         self.gpu.spec.chipset.implementation()
     }
+
+    /// Returns the total usable VRAM size of this GPU in bytes.
+    pub fn vram_size(&self) -> u64 {
+        self.gpu.gsp_static_info.vram_size()
+    }
 }
diff --git a/drivers/gpu/nova-core/gpu.rs b/drivers/gpu/nova-core/gpu.rs
index 740466af268d..3e074541af30 100644
--- a/drivers/gpu/nova-core/gpu.rs
+++ b/drivers/gpu/nova-core/gpu.rs
@@ -293,7 +293,7 @@ struct GspResources<'gpu> {
 pub(crate) struct Gpu<'gpu> {
     pub(crate) spec: Spec,
     /// Static GPU information as provided by the GSP.
-    gsp_static_info: GetGspStaticInfoReply,
+    pub(crate) gsp_static_info: GetGspStaticInfoReply,
     /// GSP and its resources.
     #[pin]
     gsp_resources: GspResources<'gpu>,
@@ -414,9 +414,7 @@ pub(crate) fn new(
                     dev_dbg!(
                         dev,
                         "Total usable VRAM: {} MiB\n",
-                        info.usable_fb_regions.iter().fold(0u64, |res, region| res
-                            .saturating_add(region.end - region.start))
-                            / u64::SZ_1M
+                        info.vram_size() / u64::SZ_1M
                     );
                 }
 
diff --git a/drivers/gpu/nova-core/gsp/commands.rs b/drivers/gpu/nova-core/gsp/commands.rs
index ffc25fd8c47b..6453184af55b 100644
--- a/drivers/gpu/nova-core/gsp/commands.rs
+++ b/drivers/gpu/nova-core/gsp/commands.rs
@@ -261,6 +261,14 @@ pub(crate) fn gpu_name(&self) -> core::result::Result<&str, GpuNameError> {
             .to_str()
             .map_err(GpuNameError::InvalidUtf8)
     }
+
+    /// Returns the total usable VRAM size in bytes, i.e. the summed lengths of all usable FB
+    /// regions.
+    pub(crate) fn vram_size(&self) -> u64 {
+        self.usable_fb_regions.iter().fold(0, |size, region| {
+            size.saturating_add(region.end - region.start)
+        })
+    }
 }
 
 pub(crate) use fw::commands::PowerStateLevel;
diff --git a/include/uapi/drm/nova_drm.h b/include/uapi/drm/nova_drm.h
index 300285b520a3..b80bb50acaa1 100644
--- a/include/uapi/drm/nova_drm.h
+++ b/include/uapi/drm/nova_drm.h
@@ -136,6 +136,12 @@ struct drm_nova_gpu_info {
 	 * @implementation: GPU implementation identifier.
 	 */
 	__u32 implementation;
+
+	/**
+	 * @vram_size: Amount of usable FB, excluding GSP carveouts and protected
+	 * regions.
+	 */
+	__u64 vram_size;
 };
 
 #define DRM_NOVA_GETPARAM		0x00
-- 
2.54.0