[PATCH v10 0/6] gpu: nova-core: expose the logging buffers via debugfs

[Timur Tabi <ttabi@nvidia.com>]

GSP-RM writes its printf messages to "logging buffers", which are blocks
of memory allocated by the driver.  The messages are encoded, so exposing
the buffers as debugfs entries allows the buffers to be extracted and
decoded by a special application.

When the driver loads, a /sys/kernel/debug/nova_core root entry is
created.  To do this, the normal module_pci_driver! macro call is
replaced with an explicit initialization function, as this allows
that debugfs entry to be created once for all GPUs.

Then in each GPU's initialization, a subdirectory based on the PCI
BDF name is created, and the logging buffer entries are created under
that.

This series depends on Eliot Courtney's Cmdq patch set [1].

Note: the debugfs entry has a file size of 0, because debugfs defaults
a 0 size and the Rust abstractions do not adjust it for the same of
the object.  Nouveau makes this adjustment manually in the driver.

[1] https://lore.kernel.org/all/20260310-cmdq-locking-v4-0-4e5c4753c408@nvidia.com/

Changes since v9:
1. Rebased onto drm-rust-next and resolved merge conflicts
2. Replaced c_str! macro with 'c' prefix
3. Improved safety and function comments in uaccess.rs
4. Replaced self.count() with more appropos self.size()
5. Added example to write_dma()

Timur Tabi (6):
  rust: device: add device name method
  rust: uaccess: add write_dma() for copying from DMA buffers to
    userspace
  rust: dma: implement BinaryWriter for CoherentAllocation<u8>
  gpu: nova-core: Replace module_pci_driver! with explicit module init
  gpu: nova-core: create debugfs root in module init
  gpu: nova-core: create GSP-RM logging buffers debugfs entries

 drivers/gpu/nova-core/gsp.rs       | 48 +++++++++++++---
 drivers/gpu/nova-core/nova_core.rs | 50 +++++++++++++++-
 rust/helpers/device.c              |  5 ++
 rust/kernel/device.rs              | 11 ++++
 rust/kernel/dma.rs                 | 35 +++++++++++-
 rust/kernel/uaccess.rs             | 92 ++++++++++++++++++++++++++----
 6 files changed, 220 insertions(+), 21 deletions(-)


base-commit: 76bce7ac51673640a4a46236ea723cf5543268d7
prerequisite-patch-id: fefd403caf8af386276351dd12397dda8ae8553f
prerequisite-patch-id: 3e02192944c4dde97e6895a28371479aa49ddc96
prerequisite-patch-id: f5f44c25a817e1e539a8418c88fe1e99d06b2c34
prerequisite-patch-id: 45041e4ac74e3ea76ea8dd0632e7746418bdf822
prerequisite-patch-id: d4f34f7eda8f5dcad2464f1bf3789e78556eb51c
-- 
2.53.0