On Tue, 24 Oct 2023 16:28:02 +0000
Benno Lossin [off-list ref] wrote:

On 24.10.23 02:58, FUJITA Tomonori wrote:

quoted

This macro creates an array of kernel's `struct phy_driver` and
registers it. This also corresponds to the kernel's
`MODULE_DEVICE_TABLE` macro, which embeds the information for module
loading into the module binary file.

A PHY driver should use this macro.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com>
---
  rust/kernel/net/phy.rs | 129 +++++++++++++++++++++++++++++++++++++++++
  1 file changed, 129 insertions(+)

diff --git a/rust/kernel/net/phy.rs b/rust/kernel/net/phy.rs
index 2d821c2475e1..f346b2b4d3cb 100644
--- a/rust/kernel/net/phy.rs
+++ b/rust/kernel/net/phy.rs

@@ -706,3 +706,132 @@ const fn as_int(&self) -> u32 {
          }
      }
  }
+
+/// Declares a kernel module for PHYs drivers.
+///
+/// This creates a static array of kernel's `struct phy_driver` and registers it.
+/// This also corresponds to the kernel's `MODULE_DEVICE_TABLE` macro, which embeds the information
+/// for module loading into the module binary file. Every driver needs an entry in `device_table`.
+///
+/// # Examples
+///
+/// ```ignore

Is this example ignored, because it does not compile?

The old version can't be compiled but the current version can so I'll
drop ignore.

I think Wedson was wrapping his example with `module!` inside
of a module, so maybe try that?

I'm not sure what you mean.

quoted

+/// use kernel::c_str;
+/// use kernel::net::phy::{self, DeviceId};
+/// use kernel::prelude::*;
+///
+/// kernel::module_phy_driver! {
+///     drivers: [PhyAX88772A],
+///     device_table: [
+///         DeviceId::new_with_driver::<PhyAX88772A>(),
+///     ],
+///     name: "rust_asix_phy",
+///     author: "Rust for Linux Contributors",
+///     description: "Rust Asix PHYs driver",
+///     license: "GPL",
+/// }
+///
+/// struct PhyAX88772A;
+///
+/// impl phy::Driver for PhyAX88772A {
+///     const NAME: &'static CStr = c_str!("Asix Electronics AX88772A");
+///     const PHY_DEVICE_ID: phy::DeviceId = phy::DeviceId::new_with_exact_mask(0x003b1861);
+/// }
+/// ```
+///
+/// This expands to the following code:
+///
+/// ```ignore
+/// use kernel::c_str;
+/// use kernel::net::phy::{self, DeviceId};
+/// use kernel::prelude::*;
+///
+/// struct Module {
+///     _reg: ::kernel::net::phy::Registration,
+/// }
+///
+/// module! {
+///     type: Module,
+///     name: "rust_asix_phy",
+///     author: "Rust for Linux Contributors",
+///     description: "Rust Asix PHYs driver",
+///     license: "GPL",
+/// }
+///
+/// const _: () = {
+///     static mut DRIVERS: [::kernel::net::phy::DriverVTable; 1] = [
+///         ::kernel::net::phy::create_phy_driver::<PhyAX88772A>::(),
+///     ];
+///
+///     impl ::kernel::Module for Module {
+///        fn init(module: &'static ThisModule) -> Result<Self> {
+///            let mut reg = unsafe { ::kernel::net::phy::Registration::register(module, Pin::static_mut(&mut DRIVERS)) }?;

Can you please format this as well?

Done.

quoted

+///            Ok(Module { _reg: reg })
+///        }
+///     }
+/// }
+///
+/// static __mod_mdio__phydev_device_table: [::kernel::bindings::mdio_device_id; 2] = [
+///     ::kernel::bindings::mdio_device_id {
+///         phy_id: 0x003b1861,
+///         phy_id_mask: 0xffffffff,
+///     },
+///     ::kernel::bindings::mdio_device_id {
+///         phy_id: 0,
+///         phy_id_mask: 0,
+///     }
+/// ];
+/// ```
+#[macro_export]
+macro_rules! module_phy_driver {
+    (@replace_expr $_t:tt $sub:expr) => {$sub};
+
+    (@count_devices $($x:expr),*) => {
+        0usize $(+ $crate::module_phy_driver!(@replace_expr $x 1usize))*
+    };
+
+    (@device_table [$($dev:expr),+]) => {
+        #[no_mangle]
+        static __mod_mdio__phydev_device_table: [
+            ::kernel::bindings::mdio_device_id;
+            $crate::module_phy_driver!(@count_devices $($dev),+) + 1
+        ] = [
+            $($dev.mdio_device_id()),+,
+            ::kernel::bindings::mdio_device_id {
+                phy_id: 0,
+                phy_id_mask: 0
+            }
+        ];
+    };
+
+    (drivers: [$($driver:ident),+], device_table: [$($dev:expr),+], $($f:tt)*) => {
+        struct Module {
+            _reg: ::kernel::net::phy::Registration,
+        }
+
+        $crate::prelude::module! {
+            type: Module,
+            $($f)*
+        }
+
+        const _: () = {
+            static mut DRIVERS: [
+                ::kernel::net::phy::DriverVTable;
+                $crate::module_phy_driver!(@count_devices $($driver),+)
+            ] = [
+                $(::kernel::net::phy::create_phy_driver::<$driver>()),+
+            ];
+
+            impl ::kernel::Module for Module {
+                fn init(module: &'static ThisModule) -> Result<Self> {
+                    // SAFETY: The anonymous constant guarantees that nobody else can access the `DRIVERS` static.
+                    // The array is used only in the C side.
+                    let mut reg = unsafe { ::kernel::net::phy::Registration::register(module, core::pin::Pin::static_mut(&mut DRIVERS)) }?;

Can you put the safe operations outside of the `unsafe` block?

fn init(module: &'static ThisModule) -> Result<Self> {
    // SAFETY: The anonymous constant guarantees that nobody else can access
    // the `DRIVERS` static. The array is used only in the C side.
    let mut reg = ::kernel::net::phy::Registration::register(
        module,
        core::pin::Pin::static_mut(unsafe { &mut DRIVERS }),
    )?;
    Ok(Module { _reg: reg })
}

Since `rustfmt` does not work well within `macro_rules`, you
have to manually format this code. One trick I use to do this
is to replace all meta variables with normal variables and
just put it in `rustfmt` and then revert the replacement in
the output.

Understood, done.