[PATCH v2 0/5] Add RC-to-EP doorbell with platform MSI controller

[Frank Li]

┌────────────┐   ┌───────────────────────────────────┐   ┌────────────────┐
│            │   │                                   │   │                │
│            │   │ PCI Endpoint                      │   │ PCI Host       │
│            │   │                                   │   │                │
│            │◄──┤ 1.platform_msi_domain_alloc_irqs()│   │                │
│            │   │                                   │   │                │
│ MSI        ├──►│ 2.write_msi_msg()                 ├──►├─BAR<n>         │
│ Controller │   │   update doorbell register address│   │                │
│            │   │   for BAR                         │   │                │
│            │   │                                   │   │ 3. Write BAR<n>│
│            │◄──┼───────────────────────────────────┼───┤                │
│            │   │                                   │   │                │
│            ├──►│ 4.Irq Handle                      │   │                │
│            │   │                                   │   │                │
│            │   │                                   │   │                │
└────────────┘   └───────────────────────────────────┘   └────────────────┘

This patches based on old https://lore.kernel.org/imx/20221124055036.1630573-1-Frank.Li@xxxxxxx/

Original patch only target to vntb driver. But actually it is common
method.

This patches add new API to pci-epf-core, so any EP driver can use it.

The key point is comments from Thomas Gleixner, who suggest use new
PCI/IMS. But arm platform change still not be merged yet.

git://git.kernel.org/pub/scm/linux/kernel/git/tglx/devel.git devmsi-v2-arm

So I still use existed method implement RC to EP doorbell.

If Thomas Gleixner want to continue work on devmsi-v2-arm, I can help test
and update this patch.

Change from v1 to v2
- Add missed patch for endpont/pci-epf-test.c
- Move alloc and free to epc driver from epf.
- Provide general help function for EPC driver to alloc platform msi irq.
- Fixed manivannan's comments.

Frank Li (5):
  PCI: endpoint: Add RC-to-EP doorbell support using platform MSI
    controller
  PCI: dwc: add doorbell support by use MSI controller
  PCI: endpoint: pci-epf-test: add doorbell test
  misc: pci_endpoint_test: Add doorbell test case
  tools: PCI: Add 'B' option for test doorbell

 drivers/misc/pci_endpoint_test.c              |  48 +++++
 .../pci/controller/dwc/pcie-designware-ep.c   |   2 +
 drivers/pci/endpoint/functions/pci-epf-test.c |  59 +++++-
 drivers/pci/endpoint/pci-epc-core.c           | 192 ++++++++++++++++++
 drivers/pci/endpoint/pci-epf-core.c           |  44 ++++
 include/linux/pci-epc.h                       |   6 +
 include/linux/pci-epf.h                       |   7 +
 include/uapi/linux/pcitest.h                  |   1 +
 tools/pci/pcitest.c                           |  16 +-
 9 files changed, 373 insertions(+), 2 deletions(-)

-- 
2.34.1