[PATCH v6 0/5] xen/arm: scmi: introduce SCI SCMI SMC multi-agent support

[Oleksii Moisieiev <Oleksii_Moisieiev@xxxxxxxx>]

Inroducing patch series which includes implementation of the SCI SCMI
SMC multi-agent support.
This patch series follows RFC v5 [3] series which was introducing both
SCMI single-agent and multi-agent support. After the discussion it was
decided to split features and upstream singe-agent support first. This
feature is merged for now to v4.21-rc2.
I'm starting this patch series from v6 to save the discussion history
and don't break changes log.

Patch 0 - xen/domctl: extend XEN_DOMCTL_assign_device to handle not
only iommu
- add chainged handling of assigned DT devices to support
access-controller functionality through SCI framework.
Change was done in two parts:
 - update iommu_do_dt_domctl() to check for dt_device_is_protected()
 and not fail if DT device is not protected by IOMMU
 -add chained call to sci_do_domctl() to do_domctl()

Patch 3 - xen/arm: scmi: introduce SCI SCMI SMC multi-agent driver
- added "scmi-secondary-agents" and "#scmi-secondary-agent-cells"
  property to "xen,config" node in "chosen" to inform SCI SCMI
  multi-agent driver about available agents and their
  configuration. It defines <agent_id> to <smc-id,scmi_shm> map.
  This option is Xen specific as Xen is the only one entry in the
  system which need to know about SCMI multi-agent support and configuration.
- each guest using SCMI should be configured with SCMI agent_id, so SCMI
  FW can implement Agent-specific permission policy.
  -- dom0: dom0_scmi_agent_id=<agent_id> in Xen command line option
  -- toolstack: arm_sci = "type=scmi_smc_multiagent,agent_id=<agent_id>"
  -- dom0less: "xen,sci_type", "xen,sci_agent_id" properties in
"xen,domain" nodes.
- factored out SCMI generic definitions (re-usable)
- factored out SCMI shmem code (re-usable)
- the SCMI passthrough configuration for guest domains is similar to any other
HW passthrough cfg.

Patch 4 - docs: arm: add SCI SCMI SMC multi-agent driver docs
- add SCI SCMI SMC multi-agent driver documentation.

Add separate SCMI DT node for Xen management agent under "xen,config"
node under chosen.

All Xen-specific configuration provided under "/chosen" node. This
approach allows to isolate modifications to Host DT only under
"/chosen" node.

This approach provides the following device tree (DT)
parameters (placed under xen,config node):

- "scmi-secondary-agents": A Xen-specific parameter under the
  "/chosen" node, which describes the SCMI agent configuration for
  the domains.
- the SCMI configuration for Xen (privileged agent) and the shared
  memory configuration for all agents are provided under the "/chosen"
  node and are used strictly by Xen for its initial configuration.
- the scmi_shm and SCMI configuration for Dom0 are placed in the
  "/firmware/scmi" node so that they can be moved to Dom0 without
  any changes.

This configuration allows the use of Xen-specific nodes to provide
information strictly needed by Xen while using the default SCMI
configuration for Dom0 and other domains. As a result, no additional
bindings need to be introduced to the device tree.
This simplifies the Xen SCMI multi-agent configuration and utilizes
generic device tree bindings for the domains.

Code can be found at:
https://github.com/oleksiimoisieiev/xen/tree/scmi_ma_upstrv6

[1] RFC v2:
http://patchwork.kernel.org/project/xen-devel/cover/cover.1644341635.git.oleksii_moisieiev@xxxxxxxx/
[2] RFC v3:
https://patchwork.kernel.org/project/xen-devel/patch/20250311111618.1850927-1-grygorii_strashko@xxxxxxxx
[3] RFC v5:
https://lore.kernel.org/xen-devel/cover.1753184487.git.oleksii_moisieiev@xxxxxxxx/
[4] SCMI single-agent:
https://lore.kernel.org/xen-devel/cover.1756995595.git.oleksii_moisieiev@xxxxxxxx/
SCMI spec:
https://developer.arm.com/documentation/den0056/e/?lang=en

SCMI bindings:
https://web.git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/devicetree/bindings/firmware/arm,scmi.yaml
https://web.git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/devicetree/bindings/access-controllers/access-controllers.yaml

Reference EL3 FW:
RPI5: https://github.com/xen-troops/arm-trusted-firmware/commits/rpi5_dev/
Renesas v4h:
https://github.com/GrygiriiS/arm-trusted-firmware/commits/rcar_gen4_v2.7_v4x-scmi_upd/

base-commit: dbe60f244c (Update Xen to 4.21, 2025-02-21)

Changes in v6:
- change iommu_do_domctl and sci_do_domctl command order and
call sci_do_domctl first which will produce cleaner code path.
Also dropped changing return code when iommu was disabled in
iommu_do_domctl.
- sorted objs in Makefile alhabetically
- added newline at the end of Makefile
- used uint{N}_t intead of u{N}
- add comment about why 32 bit IO operations were used
- updated cast opertaions to avoid dropping constness which is wrong
- move function definitions to generic place so the could be reused by
other arch
- add SPDX tag to io.c
- updated scmi-shmem to use io.h from generic location
- update scmi_agent_id parameter to be provided inside dom0= parameter
list and have the following format "dom0=sci-agent-id=0"
This change was done as a response for Stefano comment and
requires a lot of code changes, but produces much cleaner solution
that's why I've added it to the code.
- fix file comments and return codes
- fix lenght checks in shmem_{get,put}_message to use offsetof
- remove len member from scmi_channel structure as it is not used
- set scmi-secondary-agents property to be mandatory since if no
secondary agents were provided then there is no sence to enable scmi
when no secondary agents are populated to the Domains
- update documentation in booting.txt, added xen_scmi node to the
example
- adjust d->arch.sci_enabled value in scmi_domain_destroy
- fix lock management in smc_create_channel call
- avoid extra map_channel_memory command for Xen management channel
because collect_agent_id call unmaps memory if DOMID_XEN is not
set. So for Xen management channel we can init domain_id ad DOMID_XEN
before calling collect_agent_id so memory shouldn't be unmapped.
- remove all HVC mentions from the multi-agent doc
- update sci-agent-id parameter description in the documentation
- add missing Sign-of
- minor fixes across the document

Changes in v5:
- return -EINVAL if mediator without assign_dt_device was provided
- invert return code check for iommu_do_domctl in
XEN_DOMCTL_assign_device domctl processing to make cleaner code
- change -ENOTSUPP error code to -ENXIO in sci_do_domctl
- handle -ENXIO return comde of iommu_do_domctl
- leave !dt_device_is_protected check in iommu_do_dt_domctl to make
code work the same way it's done in "handle_device" call while
creating hwdom(dom0) and "handle_passthrough_prop" call for dom0less
creation
- drop return check from sci_assign_dt_device call as not needed
- do not return EINVAL when addign_dt_device is not set. That is
because this callback is optional and not implemented in single-agent driver
- move memcpy_toio/fromio to the generic place
- fix device-tree example format in booting.txt, added ";" after "}".
- update define in scmi-proto.h
- update define in scmi-shmem.h file
- scmi_assign_device - do not ignore -EOPNOTSUPP return
code of the do_smc_xfer
- remove overwriting agent_channel->agent_id after
SCMI_BASE_DISCOVER_AGENT call
- add multi-agent files to the MAINTAINERS
- add SCMI multi-agent description to the SUPPORT.md
- handle ARM_SMCCC_INVALID_PARAMETER return code and return -EINVAL
for smc call
- updated collect_agents function. Set agent_id parameter as optional
in scmi-secondary-agents device-tree property
- introduce "#scmi-secondary-agents-cells" parameter to set if
agent_id was provided
- reanme xen,scmi-secondary-agents property to scmi-secondary-agents
- move memcpu_toio/fromio for the generic place
- update Xen to get management channel from /chosen/xen,config node
- get hypervisor channnel from node instead of using hardcoded
- update handling scmi and shmem nodes for the domain
- Set multi-agent driver to support only Arm64
- rework multi-agent driver to leave Host Device-tree unmodified

Changes in v4:
- toolstack comments from Anthony PERARD
- added dom0less support
- added doc for "xen,scmi-secondary-agents"

Grygorii Strashko (2):
  xen/domctl: extend XEN_DOMCTL_assign_device to handle not only iommu
  docs: arm: add SCI SCMI SMC multi-agent driver docs

Oleksii Moisieiev (3):
  xen: arm: smccc: add INVALID_PARAMETER error code
  lib/arm: Add I/O memory copy helpers
  xen/arm: scmi: introduce SCI SCMI SMC multi-agent driver

 MAINTAINERS                                   |   4 +
 SUPPORT.md                                    |  11 +
 .../arm/firmware/arm-scmi.rst                 | 341 ++++++++
 docs/man/xl.cfg.5.pod.in                      |  13 +
 docs/misc/arm/device-tree/booting.txt         | 103 +++
 docs/misc/xen-command-line.pandoc             |  19 +-
 tools/libs/light/libxl_arm.c                  |   4 +
 tools/libs/light/libxl_types.idl              |   4 +-
 tools/xl/xl_parse.c                           |  12 +
 xen/arch/arm/dom0less-build.c                 |  11 +
 xen/arch/arm/domain_build.c                   |  26 +-
 xen/arch/arm/firmware/Kconfig                 |  12 +
 xen/arch/arm/firmware/Makefile                |   1 +
 xen/arch/arm/firmware/sci.c                   |  35 +
 xen/arch/arm/firmware/scmi-proto.h            | 164 ++++
 xen/arch/arm/firmware/scmi-shmem.c            | 115 +++
 xen/arch/arm/firmware/scmi-shmem.h            |  45 +
 xen/arch/arm/firmware/scmi-smc-multiagent.c   | 794 ++++++++++++++++++
 xen/arch/arm/include/asm/firmware/sci.h       |  14 +
 xen/arch/arm/include/asm/smccc.h              |   1 +
 xen/common/domctl.c                           |  26 +
 xen/drivers/passthrough/device_tree.c         |   6 +
 xen/include/public/arch-arm.h                 |   3 +
 xen/include/xen/lib/io.h                      |  83 ++
 xen/lib/Makefile                              |   1 +
 xen/lib/arm/Makefile                          |   1 +
 xen/lib/arm/io.c                              | 102 +++
 27 files changed, 1948 insertions(+), 3 deletions(-)
 create mode 100644 xen/arch/arm/firmware/scmi-proto.h
 create mode 100644 xen/arch/arm/firmware/scmi-shmem.c
 create mode 100644 xen/arch/arm/firmware/scmi-shmem.h
 create mode 100644 xen/arch/arm/firmware/scmi-smc-multiagent.c
 create mode 100644 xen/include/xen/lib/io.h
 create mode 100644 xen/lib/arm/Makefile
 create mode 100644 xen/lib/arm/io.c

-- 
2.34.1