Hi,
The recent introduction of heaps in the optee driver [1] made possible
the creation of heaps as modules.
It's generally a good idea if possible, including for the already
existing system and CMA heaps.
The system one is pretty trivial, the CMA one is a bit more involved,
especially since we have a call from kernel/dma/contiguous.c to the CMA
heap code. This was solved by turning the logic around and making the
CMA heap call into the contiguous DMA code.
Let me know what you think,
Maxime
1: https://lore.kernel.org/dri-devel/20250911135007.1275833-4-jens.wiklander@l…
Signed-off-by: Maxime Ripard <mripard(a)kernel.org>
---
Changes in v3:
- Squashed cma_get_name and cma_alloc/release patches
- Fixed typo in Export dev_get_cma_area commit title
- Fixed compilation failure with DMA_CMA but not OF_RESERVED_MEM
- Link to v2: https://lore.kernel.org/r/20260227-dma-buf-heaps-as-modules-v2-0-454aee7e06…
Changes in v2:
- Collect tags
- Don't export dma_contiguous_default_area anymore, but export
dev_get_cma_area instead
- Mentioned that heap modules can't be removed
- Link to v1: https://lore.kernel.org/r/20260225-dma-buf-heaps-as-modules-v1-0-2109225a09…
---
Maxime Ripard (8):
dma: contiguous: Turn heap registration logic around
dma: contiguous: Make dev_get_cma_area() a proper function
dma: contiguous: Make dma_contiguous_default_area static
dma: contiguous: Export dev_get_cma_area()
mm: cma: Export cma_alloc(), cma_release() and cma_get_name()
dma-buf: heaps: Export mem_accounting parameter
dma-buf: heaps: cma: Turn the heap into a module
dma-buf: heaps: system: Turn the heap into a module
drivers/dma-buf/dma-heap.c | 1 +
drivers/dma-buf/heaps/Kconfig | 4 ++--
drivers/dma-buf/heaps/cma_heap.c | 21 +++++----------------
drivers/dma-buf/heaps/system_heap.c | 5 +++++
include/linux/dma-map-ops.h | 18 ++++++++++--------
kernel/dma/contiguous.c | 37 ++++++++++++++++++++++++++++++++++---
mm/cma.c | 3 +++
7 files changed, 60 insertions(+), 29 deletions(-)
---
base-commit: 499a718536dc0e1c1d1b6211847207d58acd9916
change-id: 20260225-dma-buf-heaps-as-modules-1034b3ec9f2a
Best regards,
--
Maxime Ripard <mripard(a)kernel.org>
Introduce a new accel driver for the Neutron Neural Processing Unit
(NPU), along with associated dt-bindings and DTS node.
The first patch extends the GEM DMA helper APIs to allow bidirectional
mapping of non-coherent DMA buffers. While not part of the Neutron
driver, it's a prerequisite allowing us to use the GEM DMA helper.
Neutron is a Neural Processing Unit from NXP, providing machine
learning (ML) acceleration for edge AI applications. Neutron is
integrated on NXP SoCs such as the i.MX95.
The NPU consists of the following:
- RISC-V core running a proprietary firmware
- One or more Neutron cores, representing the main computation
engine performing ML operations
- Dedicated fast memory (TCM)
- DMA engine that handles data transfers between DDR and TCM
The firmware is closed source and distributed as a binary here [1].
The Neutron software stack also contains a userspace library [1] and
a LiteRT custom delegate [2] that allow integration with standard
LiteRT tools.
[1] https://github.com/nxp-upstream/neutron/tree/upstream
[2] https://github.com/nxp-imx/tflite-neutron-delegate
Signed-off-by: Ioana Ciocoi-Radulescu <ruxandra.radulescu(a)nxp.com>
---
Changes in v2:
- rebase on newer drm-misc-next
- dt bindings: clock fixes and renames
- update DTS to match new names
- remove unnecessary fields from neutron_job structure
- fix use of uninitialized variable
- Link to v1: https://lore.kernel.org/r/20260226-neutron-v1-0-46eccb3bb50a@nxp.com
---
Ioana Ciocoi-Radulescu (9):
drm/gem-dma: Add flag for bidirectional mapping of non-coherent GEM DMA buffers
accel/neutron: Add documentation for NXP Neutron accelerator driver
dt-bindings: npu: Add NXP Neutron
accel/neutron: Add driver for NXP Neutron NPU
accel/neutron: Add GEM buffer object support
accel/neutron: Add mailbox support
accel/neutron: Add job submission IOCTL
accel/neutron: Add logging support
arm64: dts: imx95: Add Neutron node
Documentation/accel/index.rst | 1 +
Documentation/accel/neutron/index.rst | 12 +
Documentation/accel/neutron/neutron.rst | 131 ++++++++
.../devicetree/bindings/npu/nxp,imx95-neutron.yaml | 96 ++++++
MAINTAINERS | 10 +
arch/arm64/boot/dts/freescale/imx95.dtsi | 28 ++
drivers/accel/Kconfig | 1 +
drivers/accel/Makefile | 3 +-
drivers/accel/neutron/Kconfig | 16 +
drivers/accel/neutron/Makefile | 12 +
drivers/accel/neutron/neutron_debugfs.c | 34 ++
drivers/accel/neutron/neutron_debugfs.h | 15 +
drivers/accel/neutron/neutron_device.c | 239 +++++++++++++
drivers/accel/neutron/neutron_device.h | 155 +++++++++
drivers/accel/neutron/neutron_driver.c | 262 +++++++++++++++
drivers/accel/neutron/neutron_driver.h | 16 +
drivers/accel/neutron/neutron_gem.c | 116 +++++++
drivers/accel/neutron/neutron_gem.h | 14 +
drivers/accel/neutron/neutron_job.c | 372 +++++++++++++++++++++
drivers/accel/neutron/neutron_job.h | 43 +++
drivers/accel/neutron/neutron_mailbox.c | 47 +++
drivers/accel/neutron/neutron_mailbox.h | 42 +++
drivers/gpu/drm/drm_gem_dma_helper.c | 6 +-
include/drm/drm_gem_dma_helper.h | 3 +
include/uapi/drm/neutron_accel.h | 130 +++++++
25 files changed, 1801 insertions(+), 3 deletions(-)
---
base-commit: 6716101ae42949e98ad4b9e71eeba08c055be410
change-id: 20260226-neutron-c435e39d167f
Best regards,
--
Ioana Ciocoi-Radulescu <ruxandra.radulescu(a)nxp.com>
