Linaro-mm-sig October 2025

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27 participants
61 discussions

[PATCH v5 0/2] accel: Add Arm Ethos-U NPU

by Rob Herring (Arm)

The Arm Ethos-U65/85 NPUs are designed for edge AI inference applications[0]. The driver works with Mesa Teflon. The Ethos support was merged on 10/15. The UAPI should also be compatible with the downstream (open source) driver stack[2] and Vela compiler though that has not been implemented. Testing so far has been on i.MX93 boards with Ethos-U65 and a FVP model with Ethos-U85. More work is needed in mesa for handling U85 command stream differences, but that doesn't affect the UAPI. A git tree is here[3]. Rob [0] https://www.arm.com/products/silicon-ip-cpu?families=ethos%20npus [2] https://gitlab.arm.com/artificial-intelligence/ethos-u/ [3] git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux.git ethos-v5 Signed-off-by: Rob Herring (Arm) <robh(a)kernel.org> --- Changes in v5: - Rework Runtime PM init in probe - Use __free() cleanups where possible - Use devm_mutex_init() - Handle U85 NPU_SET_WEIGHT2_BASE and NPU_SET_WEIGHT2_LENGTH - Link to v4: https://lore.kernel.org/r/20251015-ethos-v4-0-81025a3dcbf3@kernel.org Changes in v4: - Use bulk clk API - Various whitespace fixes mostly due to ethos->ethosu rename - Drop error check on dma_set_mask_and_coherent() - Drop unnecessary pm_runtime_mark_last_busy() call - Move variable declarations out of switch (a riscv/clang build failure) - Use lowercase hex in all defines - Drop unused ethosu_device.coherent member - Add comments on all locks - Link to v3: https://lore.kernel.org/r/20250926-ethos-v3-0-6bd24373e4f5@kernel.org Changes in v3: - Rework and improve job submit validation - Rename ethos to ethosu. There was an Ethos-Nxx that's unrelated. - Add missing init for sched_lock mutex - Drop some prints to debug level - Fix i.MX93 SRAM accesses (AXI config) - Add U85 AXI configuration and test on FVP with U85 - Print the current cmd value on timeout - Link to v2: https://lore.kernel.org/r/20250811-ethos-v2-0-a219fc52a95b@kernel.org Changes in v2: - Rebase on v6.17-rc1 adapting to scheduler changes - scheduler: Drop the reset workqueue. According to the scheduler docs, we don't need it since we have a single h/w queue. - scheduler: Rework the timeout handling to continue running if we are making progress. Fixes timeouts on larger jobs. - Reset the NPU on resume so it's in a known state - Add error handling on clk_get() calls - Fix drm_mm splat on module unload. We were missing a put on the cmdstream BO in the scheduler clean-up. - Fix 0-day report needing explicit bitfield.h include - Link to v1: https://lore.kernel.org/r/20250722-ethos-v1-0-cc1c5a0cbbfb@kernel.org --- Rob Herring (Arm) (2): dt-bindings: npu: Add Arm Ethos-U65/U85 accel: Add Arm Ethos-U NPU driver .../devicetree/bindings/npu/arm,ethos.yaml | 79 +++ MAINTAINERS | 9 + drivers/accel/Kconfig | 1 + drivers/accel/Makefile | 1 + drivers/accel/ethosu/Kconfig | 10 + drivers/accel/ethosu/Makefile | 4 + drivers/accel/ethosu/ethosu_device.h | 195 ++++++ drivers/accel/ethosu/ethosu_drv.c | 403 ++++++++++++ drivers/accel/ethosu/ethosu_drv.h | 15 + drivers/accel/ethosu/ethosu_gem.c | 704 +++++++++++++++++++++ drivers/accel/ethosu/ethosu_gem.h | 46 ++ drivers/accel/ethosu/ethosu_job.c | 540 ++++++++++++++++ drivers/accel/ethosu/ethosu_job.h | 41 ++ include/uapi/drm/ethosu_accel.h | 261 ++++++++ 14 files changed, 2309 insertions(+) --- base-commit: 3a8660878839faadb4f1a6dd72c3179c1df56787 change-id: 20250715-ethos-3fdd39ef6f19 Best regards, -- Rob Herring (Arm) <robh(a)kernel.org>

2 weeks

Re: [PATCH v8 0/2] i2c: i2c-qcom-geni: Add Block event interrupt support

by Vinod Koul

On Thu, 25 Sep 2025 17:30:33 +0530, Jyothi Kumar Seerapu wrote: > The I2C driver gets an interrupt upon transfer completion. > When handling multiple messages in a single transfer, this > results in N interrupts for N messages, leading to significant > software interrupt latency. > > To mitigate this latency, utilize Block Event Interrupt (BEI) > mechanism. Enabling BEI instructs the hardware to prevent interrupt > generation and BEI is disabled when an interrupt is necessary. > > [...] Applied, thanks! [1/2] dmaengine: qcom: gpi: Add GPI Block event interrupt support commit: 4e8331317e73902e8b2663352c8766227e633901 [2/2] i2c: i2c-qcom-geni: Add Block event interrupt support commit: 398035178503bf662281bbffb4bebce1460a4bc5 Best regards, -- ~Vinod

2 weeks

Re: [PATCH v4 2/2] accel: Add Arm Ethos-U NPU driver

by Rob Herring

On Wed, Oct 15, 2025 at 4:02 PM Frank Li <Frank.li(a)nxp.com> wrote: > > On Wed, Oct 15, 2025 at 03:36:05PM -0500, Rob Herring wrote: > > On Wed, Oct 15, 2025 at 2:39 PM Frank Li <Frank.li(a)nxp.com> wrote: > > > > > > On Wed, Oct 15, 2025 at 12:47:40PM -0500, Rob Herring (Arm) wrote: > > > > 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. > > > > +static int ethosu_init(struct ethosu_device *ethosudev) > > > > +{ > > > > + int ret; > > > > + u32 id, config; > > > > + > > > > + ret = devm_pm_runtime_enable(ethosudev->base.dev); > > > > + if (ret) > > > > + return ret; > > > > + > > > > + ret = pm_runtime_resume_and_get(ethosudev->base.dev); > > > > + if (ret) > > > > + return ret; > > > > + > > > > + pm_runtime_set_autosuspend_delay(ethosudev->base.dev, 50); > > > > + pm_runtime_use_autosuspend(ethosudev->base.dev); > > > > + > > > > + /* If PM is disabled, we need to call ethosu_device_resume() manually. */ > > > > + if (!IS_ENABLED(CONFIG_PM)) { > > > > + ret = ethosu_device_resume(ethosudev->base.dev); > > > > + if (ret) > > > > + return ret; > > > > + } > > > > > > I think it should call ethosu_device_resume() unconditional before > > > devm_pm_runtime_enable(); > > > > > > ethosu_device_resume(); > > > pm_runtime_set_active(); > > > pm_runtime_set_autosuspend_delay(ethosudev->base.dev, 50); > > > devm_pm_runtime_enable(); > > > > Why do you think this? Does this do a get? > > > > I don't think it is good to call the resume hook on our own, but we > > have no choice with !CONFIG_PM. With CONFIG_PM, we should only use the > > pm_runtime API. > > Enable clock and do some init work at probe() is quite common. But I never > seen IS_ENABLED(CONFIG_PM) check. It is quite weird and not necessary to > check CONFIG_PM flags. The most CONFIG_PM is enabled, so the branch !CONFIG_PM > almost never tested. Okay, I get what you meant. > > probe() > { > devm_clk_bulk_get_all_enabled(); > > ... did some init work > > pm_runtime_set_active(); > devm_pm_runtime_enable(); > > ... > pm_runtime_put_autosuspend(ethosudev->base.dev); > } I think we still need a pm_runtime_get_noresume() in here since we do a put later on. Here's what I have now: ret = ethosu_device_resume(ethosudev->base.dev); if (ret) return ret; pm_runtime_set_autosuspend_delay(ethosudev->base.dev, 50); pm_runtime_use_autosuspend(ethosudev->base.dev); ret = devm_pm_runtime_set_active_enabled(ethosudev->base.dev); if (ret) return ret; pm_runtime_get_noresume(ethosudev->base.dev); Rob

2 weeks

Re: [PATCH v8 2/2] i2c: i2c-qcom-geni: Add Block event interrupt support

by Vinod Koul

On 03-10-25, 20:50, Andi Shyti wrote: > On Thu, Sep 25, 2025 at 05:30:35PM +0530, Jyothi Kumar Seerapu wrote: > > From: Jyothi Kumar Seerapu <quic_jseerapu(a)quicinc.com> > > > > The I2C driver gets an interrupt upon transfer completion. > > When handling multiple messages in a single transfer, this > > results in N interrupts for N messages, leading to significant > > software interrupt latency. > > > > To mitigate this latency, utilize Block Event Interrupt (BEI) > > mechanism. Enabling BEI instructs the hardware to prevent interrupt > > generation and BEI is disabled when an interrupt is necessary. > > > > Large I2C transfer can be divided into chunks of messages internally. > > Interrupts are not expected for the messages for which BEI bit set, > > only the last message triggers an interrupt, indicating the completion of > > N messages. This BEI mechanism enhances overall transfer efficiency. > > > > BEI optimizations are currently implemented for I2C write transfers only, > > as there is no use case for multiple I2C read messages in a single transfer > > at this time. > > > > Signed-off-by: Jyothi Kumar Seerapu <quic_jseerapu(a)quicinc.com> > > Because this series is touching multiple subsystems, I'm going to > ack it: > > Acked-by: Andi Shyti <andi.shyti(a)kernel.org> > > We are waiting for someone from DMA to ack it (Vinod or Sinan). Thanks, I will pick it with your ack -- ~Vinod

2 weeks

Re: [PATCH v2] htmldocs: userspace-api/dma-buf-heaps.rst: fix block quote warning

by Bagas Sanjaya

On Thu, Oct 16, 2025 at 02:09:12AM +0000, Kriish Sharma wrote: > diff --git a/Documentation/userspace-api/dma-buf-heaps.rst b/Documentation/userspace-api/dma-buf-heaps.rst > index a0979440d2a4..c0035dc257e0 100644 > --- a/Documentation/userspace-api/dma-buf-heaps.rst > +++ b/Documentation/userspace-api/dma-buf-heaps.rst > @@ -26,6 +26,7 @@ following heaps: > ``DMABUF_HEAPS_CMA_LEGACY`` Kconfig option is set, a duplicate node is > created following legacy naming conventions; the legacy name might be > ``reserved``, ``linux,cma``, or ``default-pool``. > + > Naming Convention > ================= > LGTM, thanks! Reviewed-by: Bagas Sanjaya <bagasdotme(a)gmail.com> -- An old man doll... just what I always wanted! - Clara

2 weeks

Re: [PATCH v5 8/9] vfio/pci: Enable peer-to-peer DMA transactions by default

by Leon Romanovsky

On Wed, Oct 15, 2025 at 09:09:53PM -0700, Nicolin Chen wrote: > Hi Leon, > > On Mon, Oct 13, 2025 at 06:26:10PM +0300, Leon Romanovsky wrote: > > @@ -2090,6 +2092,9 @@ int vfio_pci_core_init_dev(struct vfio_device *core_vdev) > > INIT_LIST_HEAD(&vdev->dummy_resources_list); > > INIT_LIST_HEAD(&vdev->ioeventfds_list); > > INIT_LIST_HEAD(&vdev->sriov_pfs_item); > > + ret = pcim_p2pdma_init(vdev->pdev); > > + if (ret != -EOPNOTSUPP) > > + return ret; > > init_rwsem(&vdev->memory_lock); > > xa_init(&vdev->ctx); > > I think this should be: > if (ret && ret != -EOPNOTSUPP) > return ret; > > Otherwise, init_rwsem() and xa_init() would be missed if ret==0. You absolutely right. Thanks > > Thanks > Nicolin >

2 weeks, 1 day

Re: [PATCH] htmldocs: userspace-api/dma-buf-heaps.rst: fix block quote warning

by Bagas Sanjaya

On Wed, Oct 15, 2025 at 06:34:02PM +0000, Kriish Sharma wrote: > Fixes: 1fdbb3ff1233 ("Add linux-next specific files for 20251015") The correct blamed fixes should've been: Fixes: 507211e3c7a1 ("Documentation: dma-buf: heaps: Add naming guidelines") Thanks. -- An old man doll... just what I always wanted! - Clara

2 weeks, 1 day

Re: [PATCH] htmldocs: userspace-api/dma-buf-heaps.rst: fix block quote warning

by Randy Dunlap

On 10/15/25 11:34 AM, Kriish Sharma wrote: > Fix the following warning encountered when running `make htmldocs`: > > Documentation/userspace-api/dma-buf-heaps.rst:29: WARNING: Block quote ends without a blank line; unexpected unindent > > Added a blank line before the "Naming Convention" heading to comply with reST > > Fixes: 1fdbb3ff1233 ("Add linux-next specific files for 20251015") > Signed-off-by: Kriish Sharma <kriish.sharma2006(a)gmail.com> Reviewed-by: Randy Dunlap <rdunlap(a)infradead.org> Tested-by: Randy Dunlap <rdunlap(a)infradead.org> Thanks. > --- > Documentation/userspace-api/dma-buf-heaps.rst | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/Documentation/userspace-api/dma-buf-heaps.rst b/Documentation/userspace-api/dma-buf-heaps.rst > index a0979440d2a4..c0035dc257e0 100644 > --- a/Documentation/userspace-api/dma-buf-heaps.rst > +++ b/Documentation/userspace-api/dma-buf-heaps.rst > @@ -26,6 +26,7 @@ following heaps: > ``DMABUF_HEAPS_CMA_LEGACY`` Kconfig option is set, a duplicate node is > created following legacy naming conventions; the legacy name might be > ``reserved``, ``linux,cma``, or ``default-pool``. > + > Naming Convention > ================= > -- ~Randy

2 weeks, 1 day

Re: [PATCH v4 2/2] accel: Add Arm Ethos-U NPU driver

by Rob Herring

On Wed, Oct 15, 2025 at 2:39 PM Frank Li <Frank.li(a)nxp.com> wrote: > > On Wed, Oct 15, 2025 at 12:47:40PM -0500, Rob Herring (Arm) wrote: > > 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) and FVP (U85) with WIP Mesa Teflon > > support. > > > > Acked-by: Thomas Zimmermann <tzimmermann(a)suse.de> > > Signed-off-by: Rob Herring (Arm) <robh(a)kernel.org> > > --- > > How to test this driver? You need to add the DT node to i.MX93 .dts like the example, build the mesa ethosu branch, and then run tflite with it pointed to the mesa delegate. I can send an i.MX93 dts patch after this is merged. > > v4: > > - Use bulk clk API > > - Various whitespace fixes mostly due to ethos->ethosu rename > > - Drop error check on dma_set_mask_and_coherent() > > - Drop unnecessary pm_runtime_mark_last_busy() call > > - Move variable declarations out of switch (a riscv/clang build failure) > > - Use lowercase hex in all defines > > - Drop unused ethosu_device.coherent member > > - Add comments on all locks > > > ... > > diff --git a/drivers/accel/ethosu/ethosu_device.h b/drivers/accel/ethosu/ethosu_device.h > > new file mode 100644 > > index 000000000000..69d610c5c2d7 > > --- /dev/null > > +++ b/drivers/accel/ethosu/ethosu_device.h > > @@ -0,0 +1,190 @@ > > +/* SPDX-License-Identifier: GPL-2.0-only or MIT */ > > +/* Copyright 2025 Arm, Ltd. */ > > + > > +#ifndef __ETHOSU_DEVICE_H__ > > +#define __ETHOSU_DEVICE_H__ > > + > > +#include <linux/types.h> > > + > > +#include <drm/drm_device.h> > > +#include <drm/gpu_scheduler.h> > > + > > +#include <drm/ethosu_accel.h> > > + > > +struct clk; > > +struct gen_pool; > > Supposed should include clk.h instead declear a struct. Headers should only use a forward declaration if that's all they need. It keeps the struct opaque for starters. > ... > > + > > +static int ethosu_open(struct drm_device *ddev, struct drm_file *file) > > +{ > > + int ret = 0; > > + struct ethosu_file_priv *priv; > > + > > + if (!try_module_get(THIS_MODULE)) > > + return -EINVAL; > > + > > + priv = kzalloc(sizeof(*priv), GFP_KERNEL); > > + if (!priv) { > > + ret = -ENOMEM; > > + goto err_put_mod; > > + } > > + priv->edev = to_ethosu_device(ddev); > > + > > + ret = ethosu_job_open(priv); > > + if (ret) > > + goto err_free; > > + > > + file->driver_priv = priv; > > slice simple. > > struct ethosu_file_priv __free(kfree) *priv = NULL; > ... > priv = kzalloc(sizeof(*priv), GFP_KERNEL); Linus has voiced his opinion that the above should not be done. It should be all one line *only*. But now we allow C99 declarations, so we can move it down. We can't get rid of the goto for module_put(), so it only marginally helps here. > ... > > file->driver_priv = no_free_ptr(priv); > > > > + return 0; > > + > > +err_free: > > + kfree(priv); > > +err_put_mod: > > + module_put(THIS_MODULE); > > + return ret; > > +} > > + > ... > > + > > + > > +static int ethosu_init(struct ethosu_device *ethosudev) > > +{ > > + int ret; > > + u32 id, config; > > + > > + ret = devm_pm_runtime_enable(ethosudev->base.dev); > > + if (ret) > > + return ret; > > + > > + ret = pm_runtime_resume_and_get(ethosudev->base.dev); > > + if (ret) > > + return ret; > > + > > + pm_runtime_set_autosuspend_delay(ethosudev->base.dev, 50); > > + pm_runtime_use_autosuspend(ethosudev->base.dev); > > + > > + /* If PM is disabled, we need to call ethosu_device_resume() manually. */ > > + if (!IS_ENABLED(CONFIG_PM)) { > > + ret = ethosu_device_resume(ethosudev->base.dev); > > + if (ret) > > + return ret; > > + } > > I think it should call ethosu_device_resume() unconditional before > devm_pm_runtime_enable(); > > ethosu_device_resume(); > pm_runtime_set_active(); > pm_runtime_set_autosuspend_delay(ethosudev->base.dev, 50); > devm_pm_runtime_enable(); Why do you think this? Does this do a get? I don't think it is good to call the resume hook on our own, but we have no choice with !CONFIG_PM. With CONFIG_PM, we should only use the pm_runtime API. Rob

2 weeks, 1 day

[PATCH v4 0/2] accel: Add Arm Ethos-U NPU

by Rob Herring (Arm)

The Arm Ethos-U65/85 NPUs are designed for edge AI inference applications[0]. The driver works with Mesa Teflon. A merge request for Ethos support is here[1]. The UAPI should also be compatible with the downstream (open source) driver stack[2] and Vela compiler though that has not been implemented. Testing so far has been on i.MX93 boards with Ethos-U65 and a FVP model with Ethos-U85. More work is needed in mesa for handling U85 command stream differences, but that doesn't affect the UABI. A git tree is here[3]. Rob [0] https://www.arm.com/products/silicon-ip-cpu?families=ethos%20npus [1] https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/36699/ [2] https://gitlab.arm.com/artificial-intelligence/ethos-u/ [3] git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux.git ethos-v4 Signed-off-by: Rob Herring (Arm) <robh(a)kernel.org> --- Changes in v4: - Use bulk clk API - Various whitespace fixes mostly due to ethos->ethosu rename - Drop error check on dma_set_mask_and_coherent() - Drop unnecessary pm_runtime_mark_last_busy() call - Move variable declarations out of switch (a riscv/clang build failure) - Use lowercase hex in all defines - Drop unused ethosu_device.coherent member - Add comments on all locks - Link to v3: https://lore.kernel.org/r/20250926-ethos-v3-0-6bd24373e4f5@kernel.org Changes in v3: - Rework and improve job submit validation - Rename ethos to ethosu. There was an Ethos-Nxx that's unrelated. - Add missing init for sched_lock mutex - Drop some prints to debug level - Fix i.MX93 SRAM accesses (AXI config) - Add U85 AXI configuration and test on FVP with U85 - Print the current cmd value on timeout - Link to v2: https://lore.kernel.org/r/20250811-ethos-v2-0-a219fc52a95b@kernel.org Changes in v2: - Rebase on v6.17-rc1 adapting to scheduler changes - scheduler: Drop the reset workqueue. According to the scheduler docs, we don't need it since we have a single h/w queue. - scheduler: Rework the timeout handling to continue running if we are making progress. Fixes timeouts on larger jobs. - Reset the NPU on resume so it's in a known state - Add error handling on clk_get() calls - Fix drm_mm splat on module unload. We were missing a put on the cmdstream BO in the scheduler clean-up. - Fix 0-day report needing explicit bitfield.h include - Link to v1: https://lore.kernel.org/r/20250722-ethos-v1-0-cc1c5a0cbbfb@kernel.org --- Rob Herring (Arm) (2): dt-bindings: npu: Add Arm Ethos-U65/U85 accel: Add Arm Ethos-U NPU driver .../devicetree/bindings/npu/arm,ethos.yaml | 79 +++ MAINTAINERS | 9 + drivers/accel/Kconfig | 1 + drivers/accel/Makefile | 1 + drivers/accel/ethosu/Kconfig | 10 + drivers/accel/ethosu/Makefile | 4 + drivers/accel/ethosu/ethosu_device.h | 190 ++++++ drivers/accel/ethosu/ethosu_drv.c | 418 ++++++++++++ drivers/accel/ethosu/ethosu_drv.h | 15 + drivers/accel/ethosu/ethosu_gem.c | 710 +++++++++++++++++++++ drivers/accel/ethosu/ethosu_gem.h | 46 ++ drivers/accel/ethosu/ethosu_job.c | 539 ++++++++++++++++ drivers/accel/ethosu/ethosu_job.h | 41 ++ include/uapi/drm/ethosu_accel.h | 261 ++++++++ 14 files changed, 2324 insertions(+) --- base-commit: 3a8660878839faadb4f1a6dd72c3179c1df56787 change-id: 20250715-ethos-3fdd39ef6f19 Best regards, -- Rob Herring (Arm) <robh(a)kernel.org>

2 weeks, 1 day

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Linaro-mm-sig October 2025