1 files changed, 95 insertions, 0 deletions
diff --git a/drivers/gpu/nova-core/firmware/riscv.rs b/drivers/gpu/nova-core/firmware/riscv.rs
new file mode 100644
index 000000000000..28dfef63657a
--- /dev/null
+++ b/drivers/gpu/nova-core/firmware/riscv.rs
@@ -0,0 +1,95 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Support for firmware binaries designed to run on a RISC-V core. Such firmwares files have a
+//! dedicated header.
+
+use core::mem::size_of;
+
+use kernel::{
+    device,
+    firmware::Firmware,
+    prelude::*,
+    transmute::FromBytes, //
+};
+
+use crate::{
+    dma::DmaObject,
+    firmware::BinFirmware,
+    num::FromSafeCast, //
+};
+
+/// Descriptor for microcode running on a RISC-V core.
+#[repr(C)]
+#[derive(Debug)]
+struct RmRiscvUCodeDesc {
+    version: u32,
+    bootloader_offset: u32,
+    bootloader_size: u32,
+    bootloader_param_offset: u32,
+    bootloader_param_size: u32,
+    riscv_elf_offset: u32,
+    riscv_elf_size: u32,
+    app_version: u32,
+    manifest_offset: u32,
+    manifest_size: u32,
+    monitor_data_offset: u32,
+    monitor_data_size: u32,
+    monitor_code_offset: u32,
+    monitor_code_size: u32,
+}
+
+// SAFETY: all bit patterns are valid for this type, and it doesn't use interior mutability.
+unsafe impl FromBytes for RmRiscvUCodeDesc {}
+
+impl RmRiscvUCodeDesc {
+    /// Interprets the header of `bin_fw` as a [`RmRiscvUCodeDesc`] and returns it.
+    ///
+    /// Fails if the header pointed at by `bin_fw` is not within the bounds of the firmware image.
+    fn new(bin_fw: &BinFirmware<'_>) -> Result<Self> {
+        let offset = usize::from_safe_cast(bin_fw.hdr.header_offset);
+
+        bin_fw
+            .fw
+            .get(offset..offset + size_of::<Self>())
+            .and_then(Self::from_bytes_copy)
+            .ok_or(EINVAL)
+    }
+}
+
+/// A parsed firmware for a RISC-V core, ready to be loaded and run.
+pub(crate) struct RiscvFirmware {
+    /// Offset at which the code starts in the firmware image.
+    pub(crate) code_offset: u32,
+    /// Offset at which the data starts in the firmware image.
+    pub(crate) data_offset: u32,
+    /// Offset at which the manifest starts in the firmware image.
+    pub(crate) manifest_offset: u32,
+    /// Application version.
+    pub(crate) app_version: u32,
+    /// Device-mapped firmware image.
+    pub(crate) ucode: DmaObject,
+}
+
+impl RiscvFirmware {
+    /// Parses the RISC-V firmware image contained in `fw`.
+    pub(crate) fn new(dev: &device::Device<device::Bound>, fw: &Firmware) -> Result<Self> {
+        let bin_fw = BinFirmware::new(fw)?;
+
+        let riscv_desc = RmRiscvUCodeDesc::new(&bin_fw)?;
+
+        let ucode = {
+            let start = usize::from_safe_cast(bin_fw.hdr.data_offset);
+            let len = usize::from_safe_cast(bin_fw.hdr.data_size);
+
+            DmaObject::from_data(dev, fw.data().get(start..start + len).ok_or(EINVAL)?)?
+        };
+
+        Ok(Self {
+            ucode,
+            code_offset: riscv_desc.monitor_code_offset,
+            data_offset: riscv_desc.monitor_data_offset,
+            manifest_offset: riscv_desc.manifest_offset,
+            app_version: riscv_desc.app_version,
+        })
+    }
+}