[PATCH 0/6] Add support for Broadcom BCM2712 IOMMU driver (Raspberry Pi 5)

[Daniel Drake]

Hi,

This series adds a driver for the Broadcom BCM2712 IOMMU found on
Raspberry Pi 5, and hooks up the display controller IOMMU for efficient
management of graphics memory. This is adapted from the downstream driver
from Raspberry Pi (original author Nick Hollinghurst), with main changes:
 - Implement the page table management using generic_pt
 - Implement brcm,iova-window and brcm,iommu-cache as standards-compliant
   DT property names, while maintaining compatibility with existing
   shipped RPi firmware
 - Drop the dma-iova-offset hack, used to work around some issue seen with
   dma-ranges. This will need to be investigated separately and solved
   properly. (It's not needed for display controller iommu support included
   here.)
 - Misc simplifications/standardisations/cleanups
 
The IOMMU works strictly with 4KB pages. This means that unfortunately
when the kernel is compiled with PAGE_SIZE=16KB (the Raspberry Pi 5
kernel default), 12KB is wasted in each page that is allocated for page
tables. I plan to address this in followup work.

It has been tested on Raspberry Pi 5 using a 3D-accelerated graphical
environment which causes plenty of IOMMU maps & unmaps.

Feedback and testing welcome!

---
Daniel Drake (6):
      generic_pt: allow missing sw bit in DMA_INCOHERENT case
      iommupt: allow full-table contiguous leaves in unit tests
      dt-bindings: iommu: Add Broadcom BCM2712 IOMMU
      iommu/generic_pt: Add Broadcom BCM2712 page table format
      iommu: Add Broadcom BCM2712 IOMMU driver
      arm64: dts: broadcom: bcm2712: Add GPU IOMMU and IOMMU cache nodes

 .../bindings/iommu/brcm,bcm2712-iommu.yaml         |  65 +++
 .../bindings/iommu/brcm,bcm2712-iommuc.yaml        |  35 ++
 arch/arm64/boot/dts/broadcom/bcm2712.dtsi          |  15 +
 drivers/iommu/Kconfig                              |  15 +
 drivers/iommu/Makefile                             |   1 +
 drivers/iommu/bcm2712-iommu-cache.c                |  73 +++
 drivers/iommu/bcm2712-iommu-cache.h                |   9 +
 drivers/iommu/bcm2712-iommu.c                      | 587 +++++++++++++++++++++
 drivers/iommu/generic_pt/.kunitconfig              |   1 +
 drivers/iommu/generic_pt/Kconfig                   |  10 +
 drivers/iommu/generic_pt/fmt/Makefile              |   2 +
 drivers/iommu/generic_pt/fmt/bcm2712.h             | 259 +++++++++
 drivers/iommu/generic_pt/fmt/defs_bcm2712.h        |  18 +
 drivers/iommu/generic_pt/fmt/iommu_bcm2712.c       |  10 +
 drivers/iommu/generic_pt/kunit_generic_pt.h        |  39 +-
 drivers/iommu/generic_pt/pt_fmt_defaults.h         |  13 +
 include/linux/generic_pt/common.h                  |   7 +
 include/linux/generic_pt/iommu.h                   |  13 +
 18 files changed, 1147 insertions(+), 25 deletions(-)
---
base-commit: f4fb100039e96211609dfc44fb24b9e4a8a0f2f9
change-id: 20260712-bcm2712-iommu-submit-2e09899e65c4

Best regards,
-- 
Daniel Drake <dan@xxxxxxxxxxxxxxx>