On Tue, Sep 20, 2022 at 12:03:39AM +0530, Vidya Sagar wrote: > This series attempts to fix the issue with core register (Ex:- DBI) accesses > causing system hang issues in platforms where there is a dependency on the > availability of PCIe Reference clock from the host for their core > initialization. > This series is verified on Tegra194 & Tegra234 platforms. I think this design is just kind of weird, specifically, the fact that setting .core_init_notifier makes dw_pcie_ep_init() bail out early. The usual pattern is more like "if the specific driver sets this function pointer, the generic code calls it." The name "dw_pcie_ep_init_complete()" is not as helpful as it could be: it tells us something about what has happened before this point, but it doesn't tell us anything about what dw_pcie_ep_init_complete() *does*. Same thing with dw_pcie_ep_init_notify() -- it doesn't tell us anything about what the function *does*. I see that it calls pci_epc_init_notify(), which calls a notifier call chain (currently always empty except for a test case). I think pci_epc_linkup() is a better name because it says something about what's happening: the link is now up and we're telling somebody about it. "pci_epc_init_notify()" doesn't convey that. "pci_epc_core_initialized()" might. It looks like both qcom and tegra wait for an interrupt before calling dw_pcie_ep_init_notify(), but I'm a little concerned because I can't figure out what specifically they do to start the process that ultimately generates the interrupt. Presumably they request the IRQ *before* starting the process, but there's not much between the devm_request_threaded_irq() and the interrupt handler, which makes me wonder if both are racy. > Manivannan, could you please verify on qcom platforms? > > V4: > * Addressed review comments from Bjorn and Manivannan > * Added .ep_init_late() ops > * Added patches to refactor code in qcom and tegra platforms > > Vidya Sagar (3): > PCI: designware-ep: Fix DBI access before core init > PCI: qcom-ep: Refactor EP initialization completion > PCI: tegra194: Refactor EP initialization completion > > .../pci/controller/dwc/pcie-designware-ep.c | 112 ++++++++++-------- > drivers/pci/controller/dwc/pcie-designware.h | 10 +- > drivers/pci/controller/dwc/pcie-qcom-ep.c | 27 +++-- > drivers/pci/controller/dwc/pcie-tegra194.c | 4 +- > 4 files changed, 85 insertions(+), 68 deletions(-) > > -- > 2.17.1 >
