Mary Guillemard a778028cc5 drm/panthor: Add DEV_QUERY_TIMESTAMP_INFO dev query
Expose timestamp information supported by the GPU with a new device
query.

Mali uses an external timer as GPU system time. On ARM, this is wired to
the generic arch timer so we wire cntfrq_el0 as device frequency.

This new uAPI will be used in Mesa to implement timestamp queries and
VK_KHR_calibrated_timestamps.

Since this extends the uAPI and because userland needs a way to advertise
those features conditionally, this also bumps the driver minor version.

v2:
- Rewrote to use GPU timestamp register
- Added timestamp_offset to drm_panthor_timestamp_info
- Add missing include for arch_timer_get_cntfrq
- Rework commit message

v3:
- Add panthor_gpu_read_64bit_counter
- Change panthor_gpu_read_timestamp to use
  panthor_gpu_read_64bit_counter

v4:
- Fix multiple typos in uAPI documentation
- Mention behavior when the timestamp frequency is unknown
- Use u64 instead of unsigned long long
  for panthor_gpu_read_timestamp
- Apply r-b from Mihail

Signed-off-by: Mary Guillemard <mary.guillemard@collabora.com>
Reviewed-by: Mihail Atanassov <mihail.atanassov@arm.com>
Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>
Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240830080349.24736-2-mary.guillemard@collabora.com
2024-09-05 09:38:17 +02:00
2024-08-27 14:09:45 +02:00
2024-08-27 14:09:45 +02:00
2024-08-27 14:09:45 +02:00
2024-08-25 19:07:11 +12:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.
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