[ Upstream commit 95cbab4878 ]
drm_panthor_gpu_info::shader_present is currently automatically offset
by 4 byte to meet Arm's 32-bit/64-bit field alignment rules, but those
constraints don't stand on 32-bit x86 and cause a mismatch when running
an x86 binary in a user emulated environment like FEX. It's also
generally agreed that uAPIs should explicitly pad their struct fields,
which we originally intended to do, but a mistake slipped through during
the submission process, leading drm_panthor_gpu_info::shader_present to
be misaligned.
This uAPI change doesn't break any of the existing users of panthor
which are either arm32 or arm64 where the 64-bit alignment of
u64 fields is already enforced a the compiler level.
Changes in v2:
- Rename the garbage field into pad0 and adjust the comment accordingly
- Add Liviu's A-b
Changes in v3:
- Add R-bs
Fixes: 0f25e493a2 ("drm/panthor: Add uAPI")
Acked-by: Liviu Dudau <liviu.dudau@arm.com>
Reviewed-by: Adrián Larumbe <adrian.larumbe@collabora.com>
Reviewed-by: Steven Price <steven.price@arm.com>
Link: https://lore.kernel.org/r/20250606080932.4140010-2-boris.brezillon@collabora.com
Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
The field used to store the chunk size if 12 bits wide, and the encoding
is chunk_size = chunk_header.chunk_size << 12, which gives us a
theoretical [4k:8M] range. This range is further limited by
implementation constraints, and all known implementations seem to
impose a [128k:8M] range, so do the same here.
We also relax the power-of-two constraint, which doesn't seem to
exist on v10. This will allow userspace to fine-tune initial/max
tiler memory on memory-constrained devices.
v4:
- Actually fix the range in the kerneldoc
v3:
- Add R-bs
- Fix valid range in the kerneldoc
v2:
- Turn the power-of-two constraint into a page-aligned constraint to allow
fine-tune of the initial/max heap memory size
- Fix the panthor_heap_create() kerneldoc
Fixes: 9cca48fa4f ("drm/panthor: Add the heap logical block")
Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Reviewed-by: Liviu Dudau <liviu.dudau@arm.com>
Reviewed-by: Steven Price <steven.price@arm.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240502165158.1458959-4-boris.brezillon@collabora.com
Panthor follows the lead of other recently submitted drivers with
ioctls allowing us to support modern Vulkan features, like sparse memory
binding:
- Pretty standard GEM management ioctls (BO_CREATE and BO_MMAP_OFFSET),
with the 'exclusive-VM' bit to speed-up BO reservation on job submission
- VM management ioctls (VM_CREATE, VM_DESTROY and VM_BIND). The VM_BIND
ioctl is loosely based on the Xe model, and can handle both
asynchronous and synchronous requests
- GPU execution context creation/destruction, tiler heap context creation
and job submission. Those ioctls reflect how the hardware/scheduler
works and are thus driver specific.
We also have a way to expose IO regions, such that the usermode driver
can directly access specific/well-isolate registers, like the
LATEST_FLUSH register used to implement cache-flush reduction.
This uAPI intentionally keeps usermode queues out of the scope, which
explains why doorbell registers and command stream ring-buffers are not
directly exposed to userspace.
v6:
- Add Maxime's and Heiko's acks
v5:
- Fix typo
- Add Liviu's R-b
v4:
- Add a VM_GET_STATE ioctl
- Fix doc
- Expose the CORE_FEATURES register so we can deal with variants in the
UMD
- Add Steve's R-b
v3:
- Add the concept of sync-only VM operation
- Fix support for 32-bit userspace
- Rework drm_panthor_vm_create to pass the user VA size instead of
the kernel VA size (suggested by Robin Murphy)
- Typo fixes
- Explicitly cast enums with top bit set to avoid compiler warnings in
-pedantic mode.
- Drop property core_group_count as it can be easily calculated by the
number of bits set in l2_present.
Co-developed-by: Steven Price <steven.price@arm.com>
Signed-off-by: Steven Price <steven.price@arm.com>
Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Reviewed-by: Steven Price <steven.price@arm.com>
Reviewed-by: Liviu Dudau <liviu.dudau@arm.com>
Acked-by: Maxime Ripard <mripard@kernel.org>
Acked-by: Heiko Stuebner <heiko@sntech.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20240229162230.2634044-2-boris.brezillon@collabora.com
