[RFC 2/2] samples: rust: fwctl: add sample code for FwCtl

[Zhi Wang <zhiw@nvidia.com>]

Add sample code for creating a FwCtl device, getting device info and
issuing an RPC.

Signed-off-by: Zhi Wang <zhiw@nvidia.com>
---
 include/uapi/fwctl/fwctl.h        |   1 +
 samples/rust/Kconfig              |  11 +++
 samples/rust/Makefile             |   1 +
 samples/rust/rust_driver_fwctl.rs | 123 ++++++++++++++++++++++++++++++
 4 files changed, 136 insertions(+)
 create mode 100644 samples/rust/rust_driver_fwctl.rs

diff --git a/include/uapi/fwctl/fwctl.h b/include/uapi/fwctl/fwctl.h
index 716ac0eee42d..eea1020ad180 100644
--- a/include/uapi/fwctl/fwctl.h
+++ b/include/uapi/fwctl/fwctl.h
@@ -45,6 +45,7 @@ enum fwctl_device_type {
 	FWCTL_DEVICE_TYPE_MLX5 = 1,
 	FWCTL_DEVICE_TYPE_CXL = 2,
 	FWCTL_DEVICE_TYPE_PDS = 4,
+	FWCTL_DEVICE_TYPE_RUST_FWCTL_TEST = 8,
 };
 
 /**
diff --git a/samples/rust/Kconfig b/samples/rust/Kconfig
index c376eb899b7a..54ed2b0b86e2 100644
--- a/samples/rust/Kconfig
+++ b/samples/rust/Kconfig
@@ -138,6 +138,17 @@ config SAMPLE_RUST_DRIVER_AUXILIARY
 
 	  If unsure, say N.
 
+config SAMPLE_RUST_DRIVER_FWCTL
+	tristate "Fwctl Driver"
+	depends on FWCTL
+	help
+	  This option builds the Rust Fwctl driver sample.
+
+	  To compile this as a module, choose M here:
+	  the module will be called rust_driver_fwctl.
+
+	  If unsure, say N.
+
 config SAMPLE_RUST_HOSTPROGS
 	bool "Host programs"
 	help
diff --git a/samples/rust/Makefile b/samples/rust/Makefile
index cf8422f8f219..643208c2380e 100644
--- a/samples/rust/Makefile
+++ b/samples/rust/Makefile
@@ -12,6 +12,7 @@ obj-$(CONFIG_SAMPLE_RUST_DRIVER_PLATFORM)	+= rust_driver_platform.o
 obj-$(CONFIG_SAMPLE_RUST_DRIVER_USB)		+= rust_driver_usb.o
 obj-$(CONFIG_SAMPLE_RUST_DRIVER_FAUX)		+= rust_driver_faux.o
 obj-$(CONFIG_SAMPLE_RUST_DRIVER_AUXILIARY)	+= rust_driver_auxiliary.o
+obj-$(CONFIG_SAMPLE_RUST_DRIVER_FWCTL)		+= rust_driver_fwctl.o
 obj-$(CONFIG_SAMPLE_RUST_CONFIGFS)		+= rust_configfs.o
 
 rust_print-y := rust_print_main.o rust_print_events.o
diff --git a/samples/rust/rust_driver_fwctl.rs b/samples/rust/rust_driver_fwctl.rs
new file mode 100644
index 000000000000..386299eaf82c
--- /dev/null
+++ b/samples/rust/rust_driver_fwctl.rs
@@ -0,0 +1,123 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Rust fwctl API test (based on QEMU's `pci-testdev`).
+//!
+//! To make this driver probe, QEMU must be run with `-device pci-testdev`.
+
+use kernel::{
+    bindings, device::Core, fwctl, fwctl::FwCtlOps, fwctl::FwCtlUCtx, pci, prelude::*,
+    sync::aref::ARef,
+};
+
+struct FwCtlSampleUCtx {
+    _drvdata: u32,
+}
+
+struct FwCtlSampleOps;
+
+impl FwCtlOps for FwCtlSampleOps {
+    type UCtx = FwCtlSampleUCtx;
+
+    const DEVICE_TYPE: u32 = bindings::fwctl_device_type_FWCTL_DEVICE_TYPE_RUST_FWCTL_TEST as u32;
+
+    fn open_uctx(uctx: &mut FwCtlUCtx<FwCtlSampleUCtx>) -> Result<(), Error> {
+        let dev = uctx.get_parent_device();
+
+        dev_info!(dev, "fwctl test driver: open_uctx().\n");
+        Ok(())
+    }
+
+    fn close_uctx(uctx: &mut FwCtlUCtx<FwCtlSampleUCtx>) {
+        let dev = uctx.get_parent_device();
+
+        dev_info!(dev, "fwctl test driver: close_uctx().\n");
+    }
+
+    fn info(uctx: &mut FwCtlUCtx<FwCtlSampleUCtx>) -> Result<KVec<u8>, Error> {
+        let dev = uctx.get_parent_device();
+
+        dev_info!(dev, "fwctl test driver: info().\n");
+
+        let mut infobuf = KVec::<u8>::new();
+        infobuf.push(0xef, GFP_KERNEL)?;
+        infobuf.push(0xbe, GFP_KERNEL)?;
+        infobuf.push(0xad, GFP_KERNEL)?;
+        infobuf.push(0xde, GFP_KERNEL)?;
+
+        Ok(infobuf)
+    }
+
+    fn fw_rpc(
+        uctx: &mut FwCtlUCtx<FwCtlSampleUCtx>,
+        scope: u32,
+        rpc_in: &mut [u8],
+        _out_len: *mut usize,
+    ) -> Result<Option<KVec<u8>>, Error> {
+        let dev = uctx.get_parent_device();
+
+        dev_info!(dev, "fwctl test driver: fw_rpc() scope {}.\n", scope);
+
+        if rpc_in.len() != 4 {
+            return Err(EINVAL);
+        }
+
+        dev_info!(
+            dev,
+            "fwctl test driver: inbuf len{} bytes[0-3] {:x} {:x} {:x} {:x}.\n",
+            rpc_in.len(),
+            rpc_in[0],
+            rpc_in[1],
+            rpc_in[2],
+            rpc_in[3]
+        );
+
+        let mut outbuf = KVec::<u8>::new();
+        outbuf.push(0xef, GFP_KERNEL)?;
+        outbuf.push(0xbe, GFP_KERNEL)?;
+        outbuf.push(0xad, GFP_KERNEL)?;
+        outbuf.push(0xde, GFP_KERNEL)?;
+
+        Ok(Some(outbuf))
+    }
+}
+
+#[pin_data]
+struct FwCtlSampleDriver {
+    pdev: ARef<pci::Device>,
+    #[pin]
+    fwctl: fwctl::Registration<FwCtlSampleOps>,
+}
+
+kernel::pci_device_table!(
+    PCI_TABLE,
+    MODULE_PCI_TABLE,
+    <FwCtlSampleDriver as pci::Driver>::IdInfo,
+    [(pci::DeviceId::from_id(pci::Vendor::REDHAT, 0x5), ())]
+);
+
+impl pci::Driver for FwCtlSampleDriver {
+    type IdInfo = ();
+    const ID_TABLE: pci::IdTable<Self::IdInfo> = &PCI_TABLE;
+
+    fn probe(pdev: &pci::Device<Core>, _info: &Self::IdInfo) -> Result<Pin<KBox<Self>>> {
+        dev_info!(pdev.as_ref(), "Probe fwctl test driver.\n");
+
+        let drvdata = KBox::pin_init(
+            try_pin_init!(Self {
+                pdev: pdev.into(),
+                fwctl <- fwctl::Registration::<FwCtlSampleOps>::new(pdev.as_ref())?,
+            }),
+            GFP_KERNEL,
+        )?;
+
+        Ok(drvdata)
+    }
+}
+
+kernel::module_pci_driver! {
+    type: FwCtlSampleDriver,
+    name: "rust_driver_fwctl",
+    authors: ["Zhi Wang"],
+    description: "Rust fwctl test",
+    license: "GPL v2",
+}
-- 
2.47.3