[PATCH v5 0/8] gpu: nova-core: expose the logging buffers via debugfs

[Timur Tabi <ttabi@nvidia.com>]

GSP-RM writes its printf message to "logging buffers", which are blocks
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.

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.

Changes since v4:
1. Replaced all debugfs_lookup() code with the original global DEBUGFS_ROOT variable.
2. Added a Dir::empty() to support !DEBUGFS
3. Added UserSliceWriter::write_buffer() to avoid creating a slice over the log buffer.
4. Replaced pci::name() with device::name()

Alexandre Courbot (1):
  gpu: nova-core: implement BinaryWriter for LogBuffer

Timur Tabi (7):
  rust: pci: add device name method
  rust: debugfs: add Dir::empty() for conditional debugfs usage
  rust: uaccess: add UserSliceWriter::write_buffer() for raw pointer
    writes
  gpu: nova-core: Replace module_pci_driver! with explicit module init
  gpu: nova-core: use pin projection in method boot()
  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       | 85 +++++++++++++++++++++++++++---
 drivers/gpu/nova-core/gsp/boot.rs  | 14 ++---
 drivers/gpu/nova-core/nova_core.rs | 44 ++++++++++++++--
 rust/helpers/device.c              |  5 ++
 rust/kernel/debugfs.rs             | 18 +++++++
 rust/kernel/device.rs              | 16 ++++++
 rust/kernel/uaccess.rs             | 50 ++++++++++++++++++
 7 files changed, 215 insertions(+), 17 deletions(-)


base-commit: 654826aa4a8f25cf825ad9254f37e6cb5092098f
-- 
2.52.0