[PATCH 0/3] 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.

Frank Li (3):
  PCI: endpoint: Add RC-to-EP doorbell support using platform MSI
    controller
  misc: pci_endpoint_test: Add doorbell test case
  tools: PCI: Add 'B' option for test doorbell

 drivers/misc/pci_endpoint_test.c    |  41 +++++++++++
 drivers/pci/endpoint/pci-epf-core.c | 109 ++++++++++++++++++++++++++++
 include/linux/pci-epf.h             |  16 ++++
 include/uapi/linux/pcitest.h        |   1 +
 tools/pci/pcitest.c                 |  16 +++-
 5 files changed, 182 insertions(+), 1 deletion(-)

-- 
2.34.1