PCI: rcar-gen4: Add missing PM ops

The R-Car Gen4 PCIe controller is part of a power domain. On R-Car S4
and V4H, this is an always-on power domain which is not shut down in
suspend. On R-Car V4M, this is a dedicated A2PCIPHY power domain,
which is shut down during suspend, and the controller loses state,
which prevents the PCIe from working after resume.

Fix this by adding generic suspend/resume noirq ops for the controller,
which tear the link down on suspend, and restart it on resume. Use the
same PM ops on all of R-Car Gen4 to gracefully suspend and resume the
PCIe link on V4H and S4 too.

Test case which demonstrates the problem on R-Car V4M:

  $ hexdump -vC /sys/bus/pci/devices/0000:00:00.0/config > /tmp/pre
  $ echo s2idle > /sys/power/mem_sleep
  $ echo platform > /sys/power/pm_test
  $ echo mem > /sys/power/state
  $ hexdump -vC /sys/bus/pci/devices/0000:00:00.0/config > /tmp/post
  $ diff -Naru /tmp/pre /tmp/post
  ...
  -00000000  12 19 32 00 07 05 10 00  00 00 04 06 00 00 01 00
  +00000000  12 19 32 00 07 05 10 00  00 00 00 ff 00 00 80 00
                                            ^^^^^
                                      Class 0604->00ff

Fixes: 0270dbe4f891 ("arm64: dts: renesas: r8a779h0: Add PCIe Host and Endpoint nodes")
Reported-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Tested-by: Koichiro Den <den@valinux.co.jp>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://patch.msgid.link/20261004011851.866833-1-marek.vasut+renesas@mailbox.org

0 files changed, 0 insertions, 0 deletions