Messages in this thread | | | Date | Mon, 11 Sep 2023 09:58:04 -0700 | Subject | Re: [PATCH V13 2/5] PCI: Create device tree node for bridge | From | Lizhi Hou <> |
| |
On 9/11/23 07:48, Jonathan Cameron wrote: > On Tue, 15 Aug 2023 10:19:57 -0700 > Lizhi Hou <lizhi.hou@amd.com> wrote: > >> The PCI endpoint device such as Xilinx Alveo PCI card maps the register >> spaces from multiple hardware peripherals to its PCI BAR. Normally, >> the PCI core discovers devices and BARs using the PCI enumeration process. >> There is no infrastructure to discover the hardware peripherals that are >> present in a PCI device, and which can be accessed through the PCI BARs. >> >> Apparently, the device tree framework requires a device tree node for the >> PCI device. Thus, it can generate the device tree nodes for hardware >> peripherals underneath. Because PCI is self discoverable bus, there might >> not be a device tree node created for PCI devices. Furthermore, if the PCI >> device is hot pluggable, when it is plugged in, the device tree nodes for >> its parent bridges are required. Add support to generate device tree node >> for PCI bridges. >> >> Add an of_pci_make_dev_node() interface that can be used to create device >> tree node for PCI devices. >> >> Add a PCI_DYNAMIC_OF_NODES config option. When the option is turned on, >> the kernel will generate device tree nodes for PCI bridges unconditionally. >> >> Initially, add the basic properties for the dynamically generated device >> tree nodes which include #address-cells, #size-cells, device_type, >> compatible, ranges, reg. >> >> Acked-by: Bjorn Helgaas <bhelgaas@google.com> >> Signed-off-by: Lizhi Hou <lizhi.hou@amd.com> > I tried to bring this up for a custom PCIe card emulated in QEMU on an ARM ACPI > machine. > > There are some missing parts that were present in Clements series, but not this > one, particularly creation of the root pci object. Thanks for trying this. The entire effort was separated in different phases. That is why this patchset does not include creating of_root. > > Anyhow, hit an intermittent crash... > > >> --- >> +static int of_pci_prop_intr_map(struct pci_dev *pdev, struct of_changeset *ocs, >> + struct device_node *np) >> +{ >> + struct of_phandle_args out_irq[OF_PCI_MAX_INT_PIN]; >> + u32 i, addr_sz[OF_PCI_MAX_INT_PIN], map_sz = 0; >> + __be32 laddr[OF_PCI_ADDRESS_CELLS] = { 0 }; >> + u32 int_map_mask[] = { 0xffff00, 0, 0, 7 }; >> + struct device_node *pnode; >> + struct pci_dev *child; >> + u32 *int_map, *mapp; >> + int ret; >> + u8 pin; >> + >> + pnode = pci_device_to_OF_node(pdev->bus->self); >> + if (!pnode) >> + pnode = pci_bus_to_OF_node(pdev->bus); >> + >> + if (!pnode) { >> + pci_err(pdev, "failed to get parent device node"); >> + return -EINVAL; >> + } >> + >> + laddr[0] = cpu_to_be32((pdev->bus->number << 16) | (pdev->devfn << 8)); >> + for (pin = 1; pin <= OF_PCI_MAX_INT_PIN; pin++) { >> + i = pin - 1; >> + out_irq[i].np = pnode; >> + out_irq[i].args_count = 1; >> + out_irq[i].args[0] = pin; >> + ret = of_irq_parse_raw(laddr, &out_irq[i]); >> + if (ret) { >> + pci_err(pdev, "parse irq %d failed, ret %d", pin, ret); >> + continue; > If all the interrupt parsing fails we continue ever time...
Did you use Clement's patch to create of_root? I am just wondering if parsing irq could fail on a dt-based system.
And yes, the failure case should be handled without crash. I think if irq parsing failed, the interrupt-map pair generation should be skipped.
Thanks,
Lizhi
> >> + } >> + ret = of_property_read_u32(out_irq[i].np, "#address-cells", >> + &addr_sz[i]); >> + if (ret) >> + addr_sz[i] = 0; > This never happens. > >> + } >> + >> + list_for_each_entry(child, &pdev->subordinate->devices, bus_list) { >> + for (pin = 1; pin <= OF_PCI_MAX_INT_PIN; pin++) { >> + i = pci_swizzle_interrupt_pin(child, pin) - 1; >> + map_sz += 5 + addr_sz[i] + out_irq[i].args_count; > and here we end up derefencing random memory which happens in my case to cause > a massive allocation sometimes and that fails one of the assertions in the > allocator. > > I'd suggest just setting addr_sz[xxx] = {}; above > to ensure it's initialized. Then the if(ret) handling should not be needed > as well as of_property_read_u32 should be side effect free I hope! > >> + } >> + } >> + >> + int_map = kcalloc(map_sz, sizeof(u32), GFP_KERNEL); >> + mapp = int_map;
| |