From: Yuquan Wang <wangyuquan1236@phytium.com.cn>
v3 -> v4:
- Simplify variable definitions (Jonathan)
- Fix some alignment and space problems (Jonathan)
- Include the header file for MemoryRegion (Jonathan)
- Rebased on 'Make the CXL fixed memory windows devices'
- Keep cxl_fixed_memory_window_config() static and remove its declaration in the header file
v2 -> v3:
- Update the commit message
- Fix some alignment and space problems
- Add a SPDX header for the new file
- Remove unnecessary comments
- Add CXL_HOST_BRIDGE config
v1 -> v2:
- Move the code of new bridge to hw/pci-host/cxl.c
- Fix and simplify some logic on handling the different bridge types
Background
==========
Currently the base CXL support for arm platforms is only on Jonathan's
patches[1]. Some platform like SBSA-REF can be more like a real machine,
thus the support of CXL could be meaningful. However, the pxb-cxl-host
realization on this platform seems not satisfying their requirements[2].
New CXL HOST design
===================
Defines a new CXL host bridge type (TYPE_CXL_HOST). This is an
independent CXL host bridge which combined GPEX features (ECAM, MMIO
windows and irq) and CXL Host Bridge Component Registers (CHBCR).
The root bus path of CXL_HOST is "0001:00", that would not affect the
original pcie host topology. In the previous, the pxb-cxl-host with
any CXL root ports and CXL endpoint devices would occupy the BDF
number of the original pcie domain. This new type provide a solution
to resolve the problem.
Remaining problems
==================
I tried to use 'object_resolve_path' but it could not work in
'cxl_fmws_link', so I used 'TYPE_DEVICE' to match that.
Reviewing
=========
Welcome more PCI folks to review this patch, thanks a lot!
Link:
[1]: https://lore.kernel.org/linux-cxl/20220616141950.23374-1-Jonathan.Cameron@huawei.com/
[2]: https://lists.nongnu.org/archive/html/qemu-arm/2024-11/msg00522.html
Yuquan Wang (2):
pci-host/cxl: Support creation of a new CXL Host Bridge
hw/pxb-cxl: Rename the pxb cxl host bridge
hw/cxl/cxl-host.c | 56 +++++++---
hw/pci-bridge/pci_expander_bridge.c | 8 +-
hw/pci-host/Kconfig | 4 +
hw/pci-host/cxl.c | 146 ++++++++++++++++++++++++++
hw/pci-host/meson.build | 1 +
include/hw/cxl/cxl.h | 7 +-
include/hw/pci-host/cxl_host_bridge.h | 24 +++++
7 files changed, 229 insertions(+), 17 deletions(-)
create mode 100644 hw/pci-host/cxl.c
create mode 100644 include/hw/pci-host/cxl_host_bridge.h
--
2.34.1