PCI: endpoint: pci-epf-vntb: Add MSI doorbell support

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Add MSI doorbell support to reduce latency between PCI host and EP.

Before this change:
  ping 169.254.172.137
  64 bytes from 169.254.172.137: icmp_seq=1 ttl=64 time=0.575 ms
  64 bytes from 169.254.172.137: icmp_seq=2 ttl=64 time=1.80 ms
  64 bytes from 169.254.172.137: icmp_seq=3 ttl=64 time=8.19 ms
  64 bytes from 169.254.172.137: icmp_seq=4 ttl=64 time=2.00 ms

After this change:
  ping 169.254.144.71
  64 bytes from 169.254.144.71: icmp_seq=1 ttl=64 time=0.215 ms
  64 bytes from 169.254.144.71: icmp_seq=2 ttl=64 time=0.456 ms
  64 bytes from 169.254.144.71: icmp_seq=3 ttl=64 time=0.448 ms

Also, change the data type of 'epf_ntb::db' to 'atomic_64' as multiple
doorbell interrupts might trigger at the same time.

Signed-off-by: Frank Li <Frank.Li@nxp.com>
[mani: added 'pci_epf_' prefix to doorbell IRQ name, minor code cleanups]
Signed-off-by: Manivannan Sadhasivam <mani@kernel.org>
Link: https://patch.msgid.link/20251015-vntb_msi_doorbell-v6-4-9230298b1910@nxp.com

...

This commit is contained in:

Frank Li 2025-10-15 11:27:31 -04:00 • committed by Manivannan Sadhasivam

parent 0bfc6758f2

commit dc693d6066

1 changed files with 136 additions and 17 deletions

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153

drivers/pci/endpoint/functions/pci-epf-vntb.c

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