[v7,0/6] PCI: EP: Add RC-to-EP doorbell with platform MSI controller

Message

Frank Li Nov. 14, 2024, 10:52 p.m. UTC

┌────────────┐   ┌───────────────────────────────────┐   ┌────────────────┐
│            │   │                                   │   │                │
│            │   │ 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/[e-mail]/

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.

Previous v2 discussion here.
https://lore.kernel.org/imx/[e-mail]/

Changes in v7:
- Add helper function pci_epf_align_addr();
- Link to v6: https://lore.kernel.org/r/[e-mail]

Changes in v6:
- change doorbell_addr to doorbell_offset
- use round_down()
- add Niklas's test by tag
- rebase to pci/endpoint
- Link to v5: https://lore.kernel.org/r/[e-mail]

Changes in v5:
- Move request_irq to epf test function driver for more flexiable user case
- Add fixed size bar handler
- Some minor improvememtn to see each patches's changelog.
- Link to v4: https://lore.kernel.org/r/[e-mail]

Changes in v4:
- Remove patch genirq/msi: Add cleanup guard define for msi_lock_descs()/msi_unlock_descs()
- Use new method to avoid compatible problem.
  Add new command DOORBELL_ENABLE and DOORBELL_DISABLE.
  pcitest -B send DOORBELL_ENABLE first, EP test function driver try to
remap one of BAR_N (except test register bar) to ITS MSI MMIO space. Old
driver don't support new command, so failure return, not side effect.
  After test, DOORBELL_DISABLE command send out to recover original map, so
pcitest bar test can pass as normal.
- Other detail change see each patches's change log
- Link to v3: https://lore.kernel.org/r/[e-mail]

Change from v2 to v3
- Fixed manivannan's comments
- Move common part to pci-ep-msi.c and pci-ep-msi.h
- rebase to 6.12-rc1
- use RevID to distingiush old version

mkdir /sys/kernel/config/pci_ep/functions/pci_epf_test/func1
echo 16 > /sys/kernel/config/pci_ep/functions/pci_epf_test/func1/msi_interrupts
echo 0x080c > /sys/kernel/config/pci_ep/functions/pci_epf_test/func1/deviceid
echo 0x1957 > /sys/kernel/config/pci_ep/functions/pci_epf_test/func1/vendorid
echo 1 > /sys/kernel/config/pci_ep/functions/pci_epf_test/func1/revid
^^^^^^ to enable platform msi support.
ln -s /sys/kernel/config/pci_ep/functions/pci_epf_test/func1 /sys/kernel/config/pci_ep/controllers/4c380000.pcie-ep

- use new device ID, which identify support doorbell to avoid broken
compatility.

    Enable doorbell support only for PCI_DEVICE_ID_IMX8_DB, while other devices
    keep the same behavior as before.

           EP side             RC with old driver      RC with new driver
    PCI_DEVICE_ID_IMX8_DB          no probe              doorbell enabled
    Other device ID             doorbell disabled*       doorbell disabled*

    * Behavior remains unchanged.

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.

To: Manivannan Sadhasivam <[e-mail]>
To: Krzysztof Wilczyński <[e-mail]>
To: Kishon Vijay Abraham I <[e-mail]>
To: Bjorn Helgaas <[e-mail]>
To: Arnd Bergmann <[e-mail]>
To: Greg Kroah-Hartman <[e-mail]>
Cc: [e-mail]
Cc: [e-mail]
Cc: [e-mail]
Cc: Niklas Cassel <[e-mail]>
Cc: [e-mail]
Cc: [e-mail]
Cc: [e-mail]
Cc: [e-mail]
Cc: [e-mail]

Signed-off-by: Frank Li <[e-mail]>
---
Frank Li (6):
      PCI: endpoint: Add pci_epc_get_fn() API for customizable filtering
      PCI: endpoint: Add RC-to-EP doorbell support using platform MSI controller
      PCI: endpoint: Add pci_epf_align_addr() helper for address alignment
      PCI: endpoint: pci-epf-test: Add doorbell test support
      misc: pci_endpoint_test: Add doorbell test case
      tools: PCI: Add 'B' option for test doorbell

 drivers/misc/pci_endpoint_test.c              |  71 ++++++++++++++++
 drivers/pci/endpoint/Makefile                 |   2 +-
 drivers/pci/endpoint/functions/pci-epf-test.c | 117 ++++++++++++++++++++++++++
 drivers/pci/endpoint/pci-ep-msi.c             |  99 ++++++++++++++++++++++
 drivers/pci/endpoint/pci-epc-core.c           |  23 ++++-
 drivers/pci/endpoint/pci-epf-core.c           |  39 +++++++++
 include/linux/pci-ep-msi.h                    |  15 ++++
 include/linux/pci-epc.h                       |   2 +
 include/linux/pci-epf.h                       |  29 +++++++
 include/uapi/linux/pcitest.h                  |   1 +
 tools/pci/pcitest.c                           |  16 +++-
 11 files changed, 410 insertions(+), 4 deletions(-)
---
base-commit: f5373677e13177cfc7875f44a864f9a1db751df9
change-id: 20241010-ep-msi-8b4cab33b1be

Best regards,
---
Frank Li <[e-mail]>

Comments

Niklas Cassel Nov. 15, 2024, 9:43 a.m. UTC | #1

On Thu, Nov 14, 2024 at 05:52:36PM -0500, Frank Li wrote:
> ┌────────────┐   ┌───────────────────────────────────┐   ┌────────────────┐
> │            │   │                                   │   │                │
> │            │   │ 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/[e-mail]/
> 
> 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.
> 
> Previous v2 discussion here.
> https://lore.kernel.org/imx/[e-mail]/
> 
> Changes in v7:
> - Add helper function pci_epf_align_addr();
> - Link to v6: https://lore.kernel.org/r/[e-mail]

V7 looks very nice!

Tested-by: Niklas Cassel <[e-mail]>