Commit e66aaaff authored by Alexandre Courbot's avatar Alexandre Courbot Committed by Danilo Krummrich
Browse files

gpu: nova-core: allow register aliases 



Some registers (notably scratch registers) don't have a definitive
purpose, but need to be interpreted differently depending on context.

Expand the register!() macro to support a syntax indicating that a
register type should be at the same offset as another one, but under a
different name, and with different fields and documentation.

Signed-off-by: default avatarAlexandre Courbot <acourbot@nvidia.com>
Link: https://lore.kernel.org/r/20250619-nova-frts-v6-9-ecf41ef99252@nvidia.com


Signed-off-by: default avatarDanilo Krummrich <dakr@kernel.org>
parent cdfe233e

drivers/gpu/nova-core/regs/macros.rs

+38 −2
Original line number Diff line number Diff line
@@ -71,6 +71,20 @@ 
/// pr_info!("CPU CTL: {:#x}", cpuctl);

/// cpuctl.set_start(true).write(&bar, CPU_BASE);

/// ```

///

/// It is also possible to create a alias register by using the `=> ALIAS` syntax. This is useful

/// for cases where a register's interpretation depends on the context:

///

/// ```no_run

/// register!(SCRATCH_0 @ 0x0000100, "Scratch register 0" {

///    31:0     value as u32, "Raw value";

///

/// register!(SCRATCH_0_BOOT_STATUS => SCRATCH_0, "Boot status of the firmware" {

///     0:0     completed as bool, "Whether the firmware has completed booting";

/// ```

///

/// In this example, `SCRATCH_0_BOOT_STATUS` uses the same I/O address as `SCRATCH_0`, while also

/// providing its own `completed` method.

macro_rules! register {

    // Creates a register at a fixed offset of the MMIO space.

    (
@@ -83,6 +97,17 @@ macro_rules! register { 
        register!(@io $name @ $offset);

    };



    // Creates a alias register of fixed offset register `alias` with its own fields.

    (

        $name:ident => $alias:ident $(, $comment:literal)? {

            $($fields:tt)*

        }

    ) => {

        register!(@common $name @ $alias::OFFSET $(, $comment)?);

        register!(@field_accessors $name { $($fields)* });

        register!(@io $name @ $alias::OFFSET);

    };



    // Creates a register at a relative offset from a base address.

    (

        $name:ident @ + $offset:literal $(, $comment:literal)? {
@@ -94,11 +119,22 @@ macro_rules! register { 
        register!(@io$name @ + $offset);

    };



    // Creates a alias register of relative offset register `alias` with its own fields.

    (

        $name:ident => + $alias:ident $(, $comment:literal)? {

            $($fields:tt)*

        }

    ) => {

        register!(@common $name @ $alias::OFFSET $(, $comment)?);

        register!(@field_accessors $name { $($fields)* });

        register!(@io $name @ + $alias::OFFSET);

    };



    // All rules below are helpers.



    // Defines the wrapper `$name` type, as well as its relevant implementations (`Debug`, `BitOr`,

    // and conversion to regular `u32`).

    (@common $name:ident @ $offset:literal $(, $comment:literal)?) => {

    (@common $name:ident @ $offset:expr $(, $comment:literal)?) => {

        $(

        #[doc=$comment]

        )?
@@ -280,7 +316,7 @@ pub(crate) fn [<set_ $field>](mut self, value: $to_type) -> Self { 
    };



    // Creates the IO accessors for a fixed offset register.

    (@io $name:ident @ $offset:literal) => {

    (@io $name:ident @ $offset:expr) => {

        #[allow(dead_code)]

        impl $name {

            #[inline]