[PATCH v4 4/6] gpu: nova-core: add FbHal::frts_size() for GA100 support

[Timur Tabi <ttabi@nvidia.com>]

Introduce FbHal method frts_size() to return the size of the FRTS
window.  GA100 is a special case in that there is no FRTS, and so
the size must be set to 0.

Note that we cannot use supports_display() to determine the FRTS
size because there are other GPUs (e.g. GA102GL) that have display
disabled (and so supports_display() returns False), but the FRTS
window size still needs to be 1MB.

Signed-off-by: Timur Tabi <ttabi@nvidia.com>
Reviewed-by: Eliot Courtney <ecourtney@nvidia.com>
---
 drivers/gpu/nova-core/fb.rs           |  6 +++---
 drivers/gpu/nova-core/fb/hal.rs       |  3 +++
 drivers/gpu/nova-core/fb/hal/ga100.rs |  6 ++++++
 drivers/gpu/nova-core/fb/hal/ga102.rs |  4 ++++
 drivers/gpu/nova-core/fb/hal/tu102.rs | 11 ++++++++++-
 5 files changed, 26 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/nova-core/fb.rs b/drivers/gpu/nova-core/fb.rs
index f357fb28b22c..a305a6dac758 100644
--- a/drivers/gpu/nova-core/fb.rs
+++ b/drivers/gpu/nova-core/fb.rs
@@ -216,10 +216,10 @@ pub(crate) fn new(chipset: Chipset, bar: &Bar0, gsp_fw: &GspFirmware) -> Result<
 
         let frts = {
             const FRTS_DOWN_ALIGN: Alignment = Alignment::new::<SZ_128K>();
-            const FRTS_SIZE: u64 = usize_as_u64(SZ_1M);
-            let frts_base = vga_workspace.start.align_down(FRTS_DOWN_ALIGN) - FRTS_SIZE;
+            let frts_size: u64 = hal.frts_size();
+            let frts_base = vga_workspace.start.align_down(FRTS_DOWN_ALIGN) - frts_size;
 
-            FbRange(frts_base..frts_base + FRTS_SIZE)
+            FbRange(frts_base..frts_base + frts_size)
         };
 
         let boot = {
diff --git a/drivers/gpu/nova-core/fb/hal.rs b/drivers/gpu/nova-core/fb/hal.rs
index aba0abd8ee00..1c01a6cbed65 100644
--- a/drivers/gpu/nova-core/fb/hal.rs
+++ b/drivers/gpu/nova-core/fb/hal.rs
@@ -25,6 +25,9 @@ pub(crate) trait FbHal {
 
     /// Returns the VRAM size, in bytes.
     fn vidmem_size(&self, bar: &Bar0) -> u64;
+
+    /// Returns the FRTS size, in bytes.
+    fn frts_size(&self) -> u64;
 }
 
 /// Returns the HAL corresponding to `chipset`.
diff --git a/drivers/gpu/nova-core/fb/hal/ga100.rs b/drivers/gpu/nova-core/fb/hal/ga100.rs
index 1c03783cddef..2f5871d915c3 100644
--- a/drivers/gpu/nova-core/fb/hal/ga100.rs
+++ b/drivers/gpu/nova-core/fb/hal/ga100.rs
@@ -66,6 +66,12 @@ fn supports_display(&self, bar: &Bar0) -> bool {
     fn vidmem_size(&self, bar: &Bar0) -> u64 {
         super::tu102::vidmem_size_gp102(bar)
     }
+
+    // GA100 is a special case where its FRTS region exists, but is empty.  We
+    // return a size of 0 because we still need to record where the region starts.
+    fn frts_size(&self) -> u64 {
+        0
+    }
 }
 
 const GA100: Ga100 = Ga100;
diff --git a/drivers/gpu/nova-core/fb/hal/ga102.rs b/drivers/gpu/nova-core/fb/hal/ga102.rs
index 4b9f0f74d0e7..3bb66f64bef7 100644
--- a/drivers/gpu/nova-core/fb/hal/ga102.rs
+++ b/drivers/gpu/nova-core/fb/hal/ga102.rs
@@ -35,6 +35,10 @@ fn supports_display(&self, bar: &Bar0) -> bool {
     fn vidmem_size(&self, bar: &Bar0) -> u64 {
         vidmem_size_ga102(bar)
     }
+
+    fn frts_size(&self) -> u64 {
+        super::tu102::frts_size_tu102()
+    }
 }
 
 const GA102: Ga102 = Ga102;
diff --git a/drivers/gpu/nova-core/fb/hal/tu102.rs b/drivers/gpu/nova-core/fb/hal/tu102.rs
index 281bb796e198..22c174bf1472 100644
--- a/drivers/gpu/nova-core/fb/hal/tu102.rs
+++ b/drivers/gpu/nova-core/fb/hal/tu102.rs
@@ -2,7 +2,8 @@
 
 use kernel::{
     io::Io,
-    prelude::*, //
+    prelude::*,
+    sizes::*, //
 };
 
 use crate::{
@@ -38,6 +39,10 @@ pub(super) fn vidmem_size_gp102(bar: &Bar0) -> u64 {
         .usable_fb_size()
 }
 
+pub(super) const fn frts_size_tu102() -> u64 {
+    u64::SZ_1M
+}
+
 struct Tu102;
 
 impl FbHal for Tu102 {
@@ -56,6 +61,10 @@ fn supports_display(&self, bar: &Bar0) -> bool {
     fn vidmem_size(&self, bar: &Bar0) -> u64 {
         vidmem_size_gp102(bar)
     }
+
+    fn frts_size(&self) -> u64 {
+        frts_size_tu102()
+    }
 }
 
 const TU102: Tu102 = Tu102;
-- 
2.53.0