Hi
Am 12.08.25 um 14:56 schrieb Rob Herring:
On Tue, Aug 12, 2025 at 6:01 AM Thomas Zimmermann <tzimmerm...@suse.de> wrote:
Hi
Am 11.08.25 um 23:05 schrieb Rob Herring (Arm):
Add a driver for Arm Ethos-U65/U85 NPUs. The Ethos-U NPU has a
relatively simple interface with single command stream to describe
buffers, operation settings, and network operations. It supports up to 8
memory regions (though no h/w bounds on a region). The Ethos NPUs
are designed to use an SRAM for scratch memory. Region 2 is reserved
for SRAM (like the downstream driver stack and compiler). Userspace
doesn't need access to the SRAM.
The h/w has no MMU nor external IOMMU and is a DMA engine which can
read and write anywhere in memory without h/w bounds checks. The user
submitted command streams must be validated against the bounds of the
GEM BOs. This is similar to the VC4 design which validates shaders.
The job submit is based on the rocket driver for the Rockchip NPU
utilizing the GPU scheduler. It is simpler as there's only 1 core rather
than 3.
Tested on i.MX93 platform (U65) with WIP Mesa Teflon support.
Signed-off-by: Rob Herring (Arm) <r...@kernel.org>
I've looked over this patch and it looks good to me. There's a
dev_info() in ethos_init() of which I think it should become drm_dbg().
Anyway
I prefer to print out what h/w we've discovered. That's a fairly
common pattern for drivers (and more useful than announcing drivers
that only loaded).
Acked-by: Thomas Zimmermann <tzimmerm...@suse.de>
Thanks!
Side note: I noticed that there's buffer-allocation code here that
reinvents dumb buffers. We've ocationally talked about creating a better
dumb-buffers ioctl interface and this drivers could be another use case.
Yeah. In the past I got told don't use dumb buffers APIs for anything
but dumb scanout buffers. I guess with enough copies opinions
change...
That advice wasn't wrong. But the current dumb-buffer ioctls don't
support scanout buffers well either. If we build something new, we can
try to cover additional use cases as well.
Best regards
Thomas
Rob
--
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstrasse 146, 90461 Nuernberg, Germany
GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman
HRB 36809 (AG Nuernberg)
