On Thu Aug 20, 2026 at 8:05 AM JST, Alistair Popple wrote: > On 2026-08-10 at 23:55 +1000, Eliot Courtney <[email protected]> wrote... >> From: Joel Fernandes <[email protected]> >> >> PRAMIN apertures are a crucial mechanism for direct CPU read/write to >> VRAM. Add a `Pramin` manager whose `window_at()` returns a typed MMIO >> view of VRAM through the 1 MiB PRAMIN aperture in BAR0, validating the >> view against the VRAM region and repositioning the window as needed for >> the accessed address. >> >> A view borrows `Pramin` mutably, so the window cannot move while >> the view is in use, and it inserts an ordering point on Drop. >> >> Signed-off-by: Joel Fernandes <[email protected]> >> [ecourtney: split the registers and HAL into the two preceding patches] >> [ecourtney: rebase w.r.t. Bar0 lifetime changes and register projections] >> [ecourtney: drop the window guard and mutex, use &mut self] >> [ecourtney: position at init to avoid reads, reposition in window_offset] >> [ecourtney: return typed MMIO views instead of read/write accessors] >> [ecourtney: insert an ordering read when a view drops] >> [ecourtney: declare the window location, drop the doc examples] >> [ecourtney: add the copyright header, doc and naming cleanups] >> [ecourtney: the pramin module is mm-internal] >> Co-developed-by: Eliot Courtney <[email protected]> >> Signed-off-by: Eliot Courtney <[email protected]> >> --- >> drivers/gpu/nova-core/mm.rs | 1 + >> drivers/gpu/nova-core/mm/pramin.rs | 178 >> +++++++++++++++++++++++++++++++++++++ >> 2 files changed, 179 insertions(+) >> >> diff --git a/drivers/gpu/nova-core/mm.rs b/drivers/gpu/nova-core/mm.rs >> index 07dce4ce2473..ef5b1cad56c3 100644 >> --- a/drivers/gpu/nova-core/mm.rs >> +++ b/drivers/gpu/nova-core/mm.rs >> @@ -20,6 +20,7 @@ >> }; >> >> mod hal; >> +mod pramin; >> mod regs; >> >> /// Physical VRAM address in GPU video memory. >> diff --git a/drivers/gpu/nova-core/mm/pramin.rs >> b/drivers/gpu/nova-core/mm/pramin.rs >> new file mode 100644 >> index 000000000000..20be3fc471ba >> --- /dev/null >> +++ b/drivers/gpu/nova-core/mm/pramin.rs >> @@ -0,0 +1,178 @@ >> +// SPDX-License-Identifier: GPL-2.0 >> +// SPDX-FileCopyrightText: Copyright (c) 2026 NVIDIA CORPORATION & >> AFFILIATES. All rights reserved. >> + >> +//! Utilities for accessing VRAM through the PRAMIN window. >> + >> +use core::ops::Range; >> + >> +use kernel::{ >> + io::{ >> + io_project, >> + register, >> + register::OffsetLoc, >> + Io, >> + Mmio, // >> + }, >> + prelude::*, >> + ptr::{ >> + Alignable, >> + Alignment, // >> + }, >> + sizes::{ >> + SZ_1M, >> + SZ_64K, // >> + }, >> +}; >> + >> +use crate::{ >> + driver::{ >> + Bar0, >> + NovaRegisters, // >> + }, >> + gpu::Chipset, >> + mm::{ >> + hal::{ >> + self, >> + MmHal, // >> + }, >> + VramAddress, // >> + }, >> + num::IntoSafeCast, // >> +}; >> + >> +/// Size of the PRAMIN window (1 MiB). >> +const WINDOW_SIZE: usize = SZ_1M; >> + >> +/// The PRAMIN window, which is a 1 MiB window into VRAM at a fixed BAR0 >> offset. >> +#[derive(FromBytes, IntoBytes)] >> +struct PraminWindow([u8; WINDOW_SIZE]); >> + >> +register! { >> + base: NovaRegisters; > > I tried building this on drm-rust-next against the base commit > (4c9ba407018e8deb06dbc643112bac8f40404f95) but am getting some build errors:
I think you also need [1] (the v3 might also work, but not tested yet). [1] https://patch.msgid.link/[email protected]
