From: Alexandre Courbot Date: Fri, 18 Jul 2025 07:26:22 +0000 (+0900) Subject: gpu: nova-core: register: add support for register arrays X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=20ed4a8695b277c296e3a30306ef8551903e1e04;p=users%2Fhch%2Fmisc.git gpu: nova-core: register: add support for register arrays Having registers that can be interpreted identically in a contiguous I/O area (or at least, following a given stride) is a common way to organize registers, and is used by NVIDIA hardware. Thus, add a way to simply and safely declare such a layout using the register!() macro. Build-time bound-checking is effective for array accesses performed with a constant. For cases where the index cannot be known at compile time, `try_` variants of the accessors are also made available that return `EINVAL` if the access is out-of-bounds. Reviewed-by: Daniel Almeida Reviewed-by: Lyude Paul Link: https://lore.kernel.org/r/20250718-nova-regs-v2-17-7b6a762aa1cd@nvidia.com Signed-off-by: Alexandre Courbot --- diff --git a/drivers/gpu/nova-core/gpu.rs b/drivers/gpu/nova-core/gpu.rs index b5c9786619a9..8caecaf7dfb4 100644 --- a/drivers/gpu/nova-core/gpu.rs +++ b/drivers/gpu/nova-core/gpu.rs @@ -221,7 +221,7 @@ impl Gpu { fwsec_frts.run(dev, falcon, bar)?; // SCRATCH_E contains the error code for FWSEC-FRTS. - let frts_status = regs::NV_PBUS_SW_SCRATCH_0E::read(bar).frts_err_code(); + let frts_status = regs::NV_PBUS_SW_SCRATCH_0E_FRTS_ERR::read(bar).frts_err_code(); if frts_status != 0 { dev_err!( dev, diff --git a/drivers/gpu/nova-core/regs.rs b/drivers/gpu/nova-core/regs.rs index e55525916bad..c45de208055d 100644 --- a/drivers/gpu/nova-core/regs.rs +++ b/drivers/gpu/nova-core/regs.rs @@ -45,8 +45,10 @@ impl NV_PMC_BOOT_0 { // PBUS -// TODO[REGA]: this is an array of registers. -register!(NV_PBUS_SW_SCRATCH_0E@0x00001438 { +register!(NV_PBUS_SW_SCRATCH @ 0x00001400[64] {}); + +register!(NV_PBUS_SW_SCRATCH_0E_FRTS_ERR => NV_PBUS_SW_SCRATCH[0xe], + "scratch register 0xe used as FRTS firmware error code" { 31:16 frts_err_code as u16; }); @@ -124,13 +126,12 @@ register!(NV_PGC6_AON_SECURE_SCRATCH_GROUP_05_PRIV_LEVEL_MASK @ 0x00118128, 0:0 read_protection_level0 as bool, "Set after FWSEC lowers its protection level"; }); -// TODO[REGA]: This is an array of registers. -register!(NV_PGC6_AON_SECURE_SCRATCH_GROUP_05 @ 0x00118234 { - 31:0 value as u32; -}); +// OpenRM defines this as a register array, but doesn't specify its size and only uses its first +// element. Be conservative until we know the actual size or need to use more registers. +register!(NV_PGC6_AON_SECURE_SCRATCH_GROUP_05 @ 0x00118234[1] {}); register!( - NV_PGC6_AON_SECURE_SCRATCH_GROUP_05_0_GFW_BOOT => NV_PGC6_AON_SECURE_SCRATCH_GROUP_05, + NV_PGC6_AON_SECURE_SCRATCH_GROUP_05_0_GFW_BOOT => NV_PGC6_AON_SECURE_SCRATCH_GROUP_05[0], "Scratch group 05 register 0 used as GFW boot progress indicator" { 7:0 progress as u8, "Progress of GFW boot (0xff means completed)"; } diff --git a/drivers/gpu/nova-core/regs/macros.rs b/drivers/gpu/nova-core/regs/macros.rs index 005ee7afe279..f38177065c25 100644 --- a/drivers/gpu/nova-core/regs/macros.rs +++ b/drivers/gpu/nova-core/regs/macros.rs @@ -162,6 +162,57 @@ pub(crate) trait RegisterBase { /// // Start the aliased `CPU0`. /// CPU_CTL_ALIAS::alter(bar, &CPU0, |r| r.set_alias_start(true)); /// ``` +/// +/// ## Arrays of registers +/// +/// Some I/O areas contain consecutive values that can be interpreted in the same way. These areas +/// can be defined as an array of identical registers, allowing them to be accessed by index with +/// compile-time or runtime bound checking. Simply define their address as `Address[Size]`, and add +/// an `idx` parameter to their `read`, `write` and `alter` methods: +/// +/// ```no_run +/// # fn no_run() -> Result<(), Error> { +/// # fn get_scratch_idx() -> usize { +/// # 0x15 +/// # } +/// // Array of 64 consecutive registers with the same layout starting at offset `0x80`. +/// register!(SCRATCH @ 0x00000080[64], "Scratch registers" { +/// 31:0 value as u32; +/// }); +/// +/// // Read scratch register 0, i.e. I/O address `0x80`. +/// let scratch_0 = SCRATCH::read(bar, 0).value(); +/// // Read scratch register 15, i.e. I/O address `0x80 + (15 * 4)`. +/// let scratch_15 = SCRATCH::read(bar, 15).value(); +/// +/// // This is out of bounds and won't build. +/// // let scratch_128 = SCRATCH::read(bar, 128).value(); +/// +/// // Runtime-obtained array index. +/// let scratch_idx = get_scratch_idx(); +/// // Access on a runtime index returns an error if it is out-of-bounds. +/// let some_scratch = SCRATCH::try_read(bar, scratch_idx)?.value(); +/// +/// // Alias to a particular register in an array. +/// // Here `SCRATCH[8]` is used to convey the firmware exit code. +/// register!(FIRMWARE_STATUS => SCRATCH[8], "Firmware exit status code" { +/// 7:0 status as u8; +/// }); +/// +/// let status = FIRMWARE_STATUS::read(bar).status(); +/// +/// // Non-contiguous register arrays can be defined by adding a stride parameter. +/// // Here, each of the 16 registers of the array are separated by 8 bytes, meaning that the +/// // registers of the two declarations below are interleaved. +/// register!(SCRATCH_INTERLEAVED_0 @ 0x000000c0[16 ; 8], "Scratch registers bank 0" { +/// 31:0 value as u32; +/// }); +/// register!(SCRATCH_INTERLEAVED_1 @ 0x000000c4[16 ; 8], "Scratch registers bank 1" { +/// 31:0 value as u32; +/// }); +/// # Ok(()) +/// # } +/// ``` macro_rules! register { // Creates a register at a fixed offset of the MMIO space. ($name:ident @ $offset:literal $(, $comment:literal)? { $($fields:tt)* } ) => { @@ -187,6 +238,35 @@ macro_rules! register { register!(@io_relative $name @ $base [ $alias::OFFSET ]); }; + // Creates an array of registers at a fixed offset of the MMIO space. + ( + $name:ident @ $offset:literal [ $size:expr ; $stride:expr ] $(, $comment:literal)? { + $($fields:tt)* + } + ) => { + static_assert!(::core::mem::size_of::() <= $stride); + register!(@core $name $(, $comment)? { $($fields)* } ); + register!(@io_array $name @ $offset [ $size ; $stride ]); + }; + + // Shortcut for contiguous array of registers (stride == size of element). + ( + $name:ident @ $offset:literal [ $size:expr ] $(, $comment:literal)? { + $($fields:tt)* + } + ) => { + register!($name @ $offset [ $size ; ::core::mem::size_of::() ] $(, $comment)? { + $($fields)* + } ); + }; + + // Creates an alias of register `idx` of array of registers `alias` with its own fields. + ($name:ident => $alias:ident [ $idx:expr ] $(, $comment:literal)? { $($fields:tt)* }) => { + static_assert!($idx < $alias::SIZE); + register!(@core $name $(, $comment)? { $($fields)* } ); + register!(@io_fixed $name @ $alias::OFFSET + $idx * $alias::STRIDE ); + }; + // All rules below are helpers. // Defines the wrapper `$name` type, as well as its relevant implementations (`Debug`, @@ -520,4 +600,119 @@ macro_rules! register { } } }; + + // Generates the IO accessors for an array of registers. + (@io_array $name:ident @ $offset:literal [ $size:expr ; $stride:expr ]) => { + #[allow(dead_code)] + impl $name { + pub(crate) const OFFSET: usize = $offset; + pub(crate) const SIZE: usize = $size; + pub(crate) const STRIDE: usize = $stride; + + /// Read the array register at index `idx` from its address in `io`. + #[inline(always)] + pub(crate) fn read( + io: &T, + idx: usize, + ) -> Self where + T: ::core::ops::Deref>, + { + build_assert!(idx < Self::SIZE); + + let offset = Self::OFFSET + (idx * Self::STRIDE); + let value = io.read32(offset); + + Self(value) + } + + /// Write the value contained in `self` to the array register with index `idx` in `io`. + #[inline(always)] + pub(crate) fn write( + self, + io: &T, + idx: usize + ) where + T: ::core::ops::Deref>, + { + build_assert!(idx < Self::SIZE); + + let offset = Self::OFFSET + (idx * Self::STRIDE); + + io.write32(self.0, offset); + } + + /// Read the array register at index `idx` in `io` and run `f` on its value to obtain a + /// new value to write back. + #[inline(always)] + pub(crate) fn alter( + io: &T, + idx: usize, + f: F, + ) where + T: ::core::ops::Deref>, + F: ::core::ops::FnOnce(Self) -> Self, + { + let reg = f(Self::read(io, idx)); + reg.write(io, idx); + } + + /// Read the array register at index `idx` from its address in `io`. + /// + /// The validity of `idx` is checked at run-time, and `EINVAL` is returned is the + /// access was out-of-bounds. + #[inline(always)] + pub(crate) fn try_read( + io: &T, + idx: usize, + ) -> ::kernel::error::Result where + T: ::core::ops::Deref>, + { + if idx < Self::SIZE { + Ok(Self::read(io, idx)) + } else { + Err(EINVAL) + } + } + + /// Write the value contained in `self` to the array register with index `idx` in `io`. + /// + /// The validity of `idx` is checked at run-time, and `EINVAL` is returned is the + /// access was out-of-bounds. + #[inline(always)] + pub(crate) fn try_write( + self, + io: &T, + idx: usize, + ) -> ::kernel::error::Result where + T: ::core::ops::Deref>, + { + if idx < Self::SIZE { + Ok(self.write(io, idx)) + } else { + Err(EINVAL) + } + } + + /// Read the array register at index `idx` in `io` and run `f` on its value to obtain a + /// new value to write back. + /// + /// The validity of `idx` is checked at run-time, and `EINVAL` is returned is the + /// access was out-of-bounds. + #[inline(always)] + pub(crate) fn try_alter( + io: &T, + idx: usize, + f: F, + ) -> ::kernel::error::Result where + T: ::core::ops::Deref>, + F: ::core::ops::FnOnce(Self) -> Self, + { + if idx < Self::SIZE { + Ok(Self::alter(io, idx, f)) + } else { + Err(EINVAL) + } + } + } + }; }