[PATCH v4 0/4] xen/arm: add i.MX8M platform and UART support

[Wig Cheng <onlywig@gmail.com>]

This series adds Xen support for the NXP i.MX8M family (i.MX8MP / MQ /
MM / MN).  It provides the console UART driver, its early printk, the
platform glue (SiP SMC whitelist for the calls the dom0 kernel issues
to TF-A), and a MAINTAINERS entry.

Tested on i.MX8MP (4x Cortex-A53, GICv3) with the vendor kernel 6.18:
dom0 boots to login on the hypervisor console, and a domU starts with a
PV disk and virtio devices running a full Wayland distro.

Notes for reviewers:

- Unlike i.MX8MQ, the i.MX8MP device tree uses the GIC as the root
  interrupt controller (interrupt-parent = <&gic>), so no device-tree
  workaround is needed and power domains keep working.

- The i.MX8M family has no SMMU, so device passthrough relies on the
  1:1 direct-mapped hardware domain.

- The SiP SMC whitelist forwards only the specific subfunctions the
  dom0 kernel issues, extracted from the vendor kernel call sites.  CPU
  and DRAM frequency scaling are both denied: the hardware domain
  cannot make an informed decision about resources it shares with the
  other domains.  dom0's i.MX8M DDRC devfreq driver issues the DDR DVFS
  call at boot; with it denied that driver just skips DRAM frequency
  scaling (the DRAM stays at the frequency set by firmware) and dom0
  boots normally.

Changes since v3:

- Patch 3: filter the SRC and NoC subfunctions with an explicit switch
  that lists each accepted subfunction, instead of a range check
  (Michal Orzel).  The NoC service now accepts only the QoS priority
  subfunction, and the unknown-function-id warning also prints the
  subfunction id.
- Patches 1, 2 and 4 are unchanged; all four patches now carry Michal's
  Reviewed-by.

Per-patch changelogs are in each patch.

v3: https://lore.kernel.org/xen-devel/20260818153946.1635464-1-onlywig@gmail.com/

Wig Cheng (4):
  xen/char: add classic i.MX UART driver
  xen/arm64: add early printk for the classic i.MX UART
  xen/arm: add i.MX8M platform support
  MAINTAINERS: add myself as reviewer of i.MX8M related patches

 MAINTAINERS                           |   8 +
 xen/arch/arm/Kconfig.debug            |  12 ++
 xen/arch/arm/arm64/debug-imx-uart.inc |  37 ++++
 xen/arch/arm/include/asm/imx-uart.h   |  57 +++++++
 xen/arch/arm/platforms/Makefile       |   1 +
 xen/arch/arm/platforms/imx8m.c        | 161 ++++++++++++++++++
 xen/drivers/char/Kconfig              |   8 +
 xen/drivers/char/Makefile             |   1 +
 xen/drivers/char/imx-uart.c           | 233 ++++++++++++++++++++++++++
 9 files changed, 518 insertions(+)
 create mode 100644 xen/arch/arm/arm64/debug-imx-uart.inc
 create mode 100644 xen/arch/arm/include/asm/imx-uart.h
 create mode 100644 xen/arch/arm/platforms/imx8m.c
 create mode 100644 xen/drivers/char/imx-uart.c

-- 
2.43.0