linux/Documentation/gpu/driver-uapi.rst

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drm/panthor: Add uAPI 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
2024-02-29 17:22:15 +01:00
drm: Add UAPI for the Asahi driver This adds the UAPI for the Asahi driver targeting the GPU in the Apple M1 and M2 series systems on chip. The UAPI design is based on other modern Vulkan-capable drivers, including Xe and Panthor. Memory management is based on explicit VM management. Synchronization is exclusively explicit sync. This UAPI is validated against our open source Mesa stack, which is fully conformant to the OpenGL 4.6, OpenGL ES 3.2, OpenCL 3.0, and Vulkan 1.4 standards. The Vulkan driver supports sparse, exercising the VM_BIND mechanism. This patch adds the standalone UAPI header. It is implemented by an open source DRM driver written in Rust. We fully intend to upstream this driver when possible. However, as a production graphics driver, it depends on a significant number of Rust abstractions that will take a long time to upstream. In the mean time, our userspace is upstream in Mesa but is not allowed to probe with upstream Mesa as the UAPI is not yet reviewed and merged in the upstream kernel. Although we ship a patched Mesa in Fedora Asahi Remix, any containers shipping upstream Mesa builds are broken for our users, including upstream Flatpak and Waydroid runtimes. Additionally, it forces us to maintain forks of Mesa and virglrenderer, which complicates bisects. The intention in sending out this patch is for this UAPI to be thoroughly reviewed. Once we as the DRM community are satisfied with the UAPI, this header lands signifying that the UAPI is stable and must only be evolved in backwards-compatible ways; it will be the UAPI implemented in the DRM driver that eventually lands upstream. That promise lets us enable upstream Mesa, solving all these issues while the upstream Rust abstractions are developed. https://github.com/alyssarosenzweig/linux/commits/agx-uapi-v7 contains the DRM driver implementing this proposed UAPI. https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/33984 contains the Mesa patches to implement this proposed UAPI. That Linux and Mesa branch together give a complete graphics/compute stack on top of this UAPI. Co-developed-by: Asahi Lina <lina@asahilina.net> Signed-off-by: Asahi Lina <lina@asahilina.net> Acked-by: Simona Vetter <simona.vetter@ffwll.ch> Reviewed-by: Neal Gompa <neal@gompa.dev> Reviewed-by: Janne Grunau <j@jannau.net> Reviewed-by: Faith Ekstrand <faith.ekstrand@collabora.com> Link: https://lore.kernel.org/r/20250408-agx-uapi-v7-1-ad122d4f7324@rosenzweig.io Signed-off-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
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