gpu: nova-core: mm: Add support to use PRAMIN windows to write to VRAM

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 <joelagnelf@nvidia.com>
[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 <ecourtney@nvidia.com>
Signed-off-by: Eliot Courtney <ecourtney@nvidia.com>
Acked-by: Danilo Krummrich <dakr@kernel.org>
Link: https://patch.msgid.link/20260827-pramin-split-v3-6-24b24d7afc52@nvidia.com
Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>

0 files changed, 0 insertions, 0 deletions