[PATCH v5 1/3] gpu: nova-core: prepare Spec and Revision types for boot0/boot42

[John Hubbard <jhubbard@nvidia.com>]

1) Implement Display for Spec. This simplifies the dev_info!() code for
   printing banners such as:

    NVIDIA (Chipset: GA104, Architecture: Ampere, Revision: a.1)

2) Decouple Revision from boot0.

3) Enhance Revision, which in turn simplifies Spec::new().

4) Also, slightly enhance the comment about Spec, to be more precise.

Cc: Alexandre Courbot <acourbot@nvidia.com>
Cc: Danilo Krummrich <dakr@kernel.org>
Cc: Timur Tabi <ttabi@nvidia.com>
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
---
 drivers/gpu/nova-core/gpu.rs  | 45 +++++++++++++++++++----------------
 drivers/gpu/nova-core/regs.rs |  8 +++++++
 2 files changed, 33 insertions(+), 20 deletions(-)

diff --git a/drivers/gpu/nova-core/gpu.rs b/drivers/gpu/nova-core/gpu.rs
index 9d182bffe8b4..8173cdcd8378 100644
--- a/drivers/gpu/nova-core/gpu.rs
+++ b/drivers/gpu/nova-core/gpu.rs
@@ -130,16 +130,18 @@ fn try_from(value: u8) -> Result<Self> {
 }
 
 pub(crate) struct Revision {
-    major: u8,
-    minor: u8,
+    pub(crate) major: u8,
+    pub(crate) minor: u8,
 }
 
-impl Revision {
-    fn from_boot0(boot0: regs::NV_PMC_BOOT_0) -> Self {
-        Self {
-            major: boot0.major_revision(),
-            minor: boot0.minor_revision(),
-        }
+impl TryFrom<regs::NV_PMC_BOOT_0> for Spec {
+    type Error = Error;
+
+    fn try_from(boot0: regs::NV_PMC_BOOT_0) -> Result<Self> {
+        Ok(Self {
+            chipset: boot0.chipset()?,
+            revision: boot0.revision(),
+        })
     }
 }
 
@@ -149,7 +151,7 @@ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
     }
 }
 
-/// Structure holding the metadata of the GPU.
+/// Structure holding a basic description of the GPU: Architecture, Chipset and Revision.
 pub(crate) struct Spec {
     chipset: Chipset,
     /// The revision of the chipset.
@@ -160,10 +162,19 @@ impl Spec {
     fn new(bar: &Bar0) -> Result<Spec> {
         let boot0 = regs::NV_PMC_BOOT_0::read(bar);
 
-        Ok(Self {
-            chipset: boot0.chipset()?,
-            revision: Revision::from_boot0(boot0),
-        })
+        Spec::try_from(boot0)
+    }
+}
+
+impl fmt::Display for Spec {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(
+            f,
+            "Chipset: {}, Architecture: {:?}, Revision: {}",
+            self.chipset,
+            self.chipset.arch(),
+            self.revision
+        )
     }
 }
 
@@ -193,13 +204,7 @@ pub(crate) fn new<'a>(
     ) -> impl PinInit<Self, Error> + 'a {
         try_pin_init!(Self {
             spec: Spec::new(bar).inspect(|spec| {
-                dev_info!(
-                    pdev.as_ref(),
-                    "NVIDIA (Chipset: {}, Architecture: {:?}, Revision: {})\n",
-                    spec.chipset,
-                    spec.chipset.arch(),
-                    spec.revision
-                );
+                dev_info!(pdev.as_ref(),"NVIDIA ({})\n", spec);
             })?,
 
             // We must wait for GFW_BOOT completion before doing any significant setup on the GPU.
diff --git a/drivers/gpu/nova-core/regs.rs b/drivers/gpu/nova-core/regs.rs
index 206dab2e1335..207b865335af 100644
--- a/drivers/gpu/nova-core/regs.rs
+++ b/drivers/gpu/nova-core/regs.rs
@@ -41,6 +41,14 @@ pub(crate) fn chipset(self) -> Result<Chipset> {
             })
             .and_then(Chipset::try_from)
     }
+
+    /// Returns the revision information of the chip.
+    pub(crate) fn revision(self) -> crate::gpu::Revision {
+        crate::gpu::Revision {
+            major: self.major_revision(),
+            minor: self.minor_revision(),
+        }
+    }
 }
 
 // PBUS
-- 
2.51.2