PCI: qcom: Add ICC bandwidth vote for CPU to PCIe path
authorKrishna chaitanya chundru <quic_krichai@quicinc.com>
Wed, 19 Jun 2024 15:11:10 +0000 (20:41 +0530)
committerBjorn Helgaas <bhelgaas@google.com>
Tue, 9 Jul 2024 21:56:32 +0000 (16:56 -0500)
commit980136d1c2b95644b96df6c7ec00ca5d7c87f37f
treeeb39bd637981ff2fc5736c7052c694da6b9bbd13
parent912315715d7b74f7abdb6f063ebace44ee288af9
PCI: qcom: Add ICC bandwidth vote for CPU to PCIe path

To access the host controller registers of the host controller and the
endpoint BAR/config space, the CPU-PCIe ICC (interconnect) path should
be voted otherwise it may lead to NoC (Network on chip) timeout.
We are surviving because of other driver voting for this path.

As there is less access on this path compared to PCIe to mem path
add minimum vote i.e 1KBps bandwidth always which is sufficient enough
to keep the path active and is recommended by HW team.

During S2RAM (Suspend-to-RAM), the DBI access can happen very late (while
disabling the boot CPU). So do not disable the CPU-PCIe interconnect path
during S2RAM as that may lead to NoC error.

Link: https://lore.kernel.org/linux-pci/20240619-opp_support-v15-1-aa769a2173a3@quicinc.com
Signed-off-by: Krishna chaitanya chundru <quic_krichai@quicinc.com>
Signed-off-by: Krzysztof WilczyƄski <kwilczynski@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
drivers/pci/controller/dwc/pcie-qcom.c