[PATCH v2 19/32] gpu: nova-core: gsp: factor out NVKV payload conversion

[Zhi Wang <zhiw@nvidia.com>]

Both GSP initialization and vGPU property queries decode their replies as
NVKV streams.

Move the byte-to-word conversion helper into the NVKV module and make
that module accessible to the vGPU firmware interface.

No functional change is intended.

Signed-off-by: Zhi Wang <zhiw@nvidia.com>
---
 drivers/gpu/nova-core/gsp.rs          |  2 +-
 drivers/gpu/nova-core/gsp/commands.rs | 24 +-----------------------
 drivers/gpu/nova-core/gsp/nvkv.rs     | 24 ++++++++++++++++++++++++
 3 files changed, 26 insertions(+), 24 deletions(-)

diff --git a/drivers/gpu/nova-core/gsp.rs b/drivers/gpu/nova-core/gsp.rs
index 93291c67d6de..5b1e4eb7cad8 100644
--- a/drivers/gpu/nova-core/gsp.rs
+++ b/drivers/gpu/nova-core/gsp.rs
@@ -24,7 +24,7 @@
 pub(crate) mod cmdq;
 pub(crate) mod commands;
 mod fw;
-mod nvkv;
+pub(crate) mod nvkv;
 mod regs;
 
 pub(crate) use fw::{
diff --git a/drivers/gpu/nova-core/gsp/commands.rs b/drivers/gpu/nova-core/gsp/commands.rs
index 7ca5ec2a58d9..7945a191bd08 100644
--- a/drivers/gpu/nova-core/gsp/commands.rs
+++ b/drivers/gpu/nova-core/gsp/commands.rs
@@ -33,6 +33,7 @@
             GMCAPI_CMD_GSP_SUSPEND, //
         },
         nvkv::{
+            nvkv_words,
             Decoder,
             Encodable,
             EncodedStream,
@@ -41,7 +42,6 @@
         },
         GspBootContext,
     },
-    sbuffer::SBufferIter,
     vgpu::VgpuState, //
 };
 
@@ -256,28 +256,6 @@ fn decode_gsp_init_reply(
     decode_gsp_info(&nvkv_words(payload_0, payload_1)?)
 }
 
-/// Joins the two halves of a wrapped payload into the `u64` words an NVKV stream is made of.
-///
-/// # Errors
-///
-/// - `EIO` if the combined length is not a whole number of words.
-/// - `ENOMEM` if the buffer cannot be allocated.
-fn nvkv_words(payload_0: &[u8], payload_1: &[u8]) -> Result<KVVec<u64>> {
-    let bytes = SBufferIter::new_reader([payload_0, payload_1]).flush_into_kvec(GFP_KERNEL)?;
-    let words = bytes.chunks_exact(size_of::<u64>());
-    if !words.remainder().is_empty() {
-        return Err(EIO);
-    }
-
-    let mut out = KVVec::with_capacity(bytes.len() / size_of::<u64>(), GFP_KERNEL)?;
-    for word in words {
-        let word: [u8; size_of::<u64>()] = word.try_into().map_err(|_| EIO)?;
-        out.push(u64::from_le_bytes(word), GFP_KERNEL)?;
-    }
-
-    Ok(out)
-}
-
 /// Decodes the static GPU configuration from an NVKV stream.
 ///
 /// # Errors
diff --git a/drivers/gpu/nova-core/gsp/nvkv.rs b/drivers/gpu/nova-core/gsp/nvkv.rs
index e7a9549919fb..9f2119b98b26 100644
--- a/drivers/gpu/nova-core/gsp/nvkv.rs
+++ b/drivers/gpu/nova-core/gsp/nvkv.rs
@@ -27,6 +27,30 @@
 };
 use zerocopy::Immutable;
 
+use crate::sbuffer::SBufferIter;
+
+/// Joins the two halves of a wrapped payload into the `u64` words an NVKV stream is made of.
+///
+/// # Errors
+///
+/// - `EIO` if the combined length is not a whole number of words.
+/// - `ENOMEM` if the buffer cannot be allocated.
+pub(crate) fn nvkv_words(payload_0: &[u8], payload_1: &[u8]) -> Result<KVVec<u64>> {
+    let bytes = SBufferIter::new_reader([payload_0, payload_1]).flush_into_kvec(GFP_KERNEL)?;
+    let words = bytes.chunks_exact(size_of::<u64>());
+    if !words.remainder().is_empty() {
+        return Err(EIO);
+    }
+
+    let mut out = KVVec::with_capacity(bytes.len() / size_of::<u64>(), GFP_KERNEL)?;
+    for word in words {
+        let word: [u8; size_of::<u64>()] = word.try_into().map_err(|_| EIO)?;
+        out.push(u64::from_le_bytes(word), GFP_KERNEL)?;
+    }
+
+    Ok(out)
+}
+
 mod encode;
 pub(crate) use encode::*;