Hello Sam, On 9/10/18 7:47 AM, Sam Bobroff wrote: > Hi Sergey, > > On Thu, Sep 06, 2018 at 02:57:49PM +0300, Sergey Miroshnichenko wrote: >> The pci_dn structures can be created not only from DT, but also >> directly from newly discovered PCIe devices, so allocate them >> dynamically. >> >> Signed-off-by: Sergey Miroshnichenko <s.miroshniche...@yadro.com> >> --- >> arch/powerpc/kernel/pci_dn.c | 76 ++++++++++++++++++++++++++++-------- >> 1 file changed, 59 insertions(+), 17 deletions(-) >> >> diff --git a/arch/powerpc/kernel/pci_dn.c b/arch/powerpc/kernel/pci_dn.c >> index ab147a1909c8..48ec16407835 100644 >> --- a/arch/powerpc/kernel/pci_dn.c >> +++ b/arch/powerpc/kernel/pci_dn.c >> @@ -33,6 +33,8 @@ >> #include <asm/firmware.h> >> #include <asm/eeh.h> >> >> +static struct pci_dn *create_pdn(struct pci_dev *pdev, struct pci_dn >> *parent); >> + >> /* >> * The function is used to find the firmware data of one >> * specific PCI device, which is attached to the indicated >> @@ -58,6 +60,9 @@ static struct pci_dn *pci_bus_to_pdn(struct pci_bus *bus) >> pbus = pbus->parent; >> } >> >> + if (!pbus->self && !pci_is_root_bus(pbus)) >> + return NULL; >> + >> /* >> * Except virtual bus, all PCI buses should >> * have device nodes. >> @@ -65,13 +70,15 @@ static struct pci_dn *pci_bus_to_pdn(struct pci_bus *bus) >> dn = pci_bus_to_OF_node(pbus); >> pdn = dn ? PCI_DN(dn) : NULL; >> >> + if (!pdn && pbus->self) >> + pdn = pbus->self->dev.archdata.pci_data; >> + >> return pdn; >> } >> >> struct pci_dn *pci_get_pdn_by_devfn(struct pci_bus *bus, >> int devfn) >> { >> - struct device_node *dn = NULL; >> struct pci_dn *parent, *pdn; >> struct pci_dev *pdev = NULL; >> >> @@ -80,17 +87,10 @@ struct pci_dn *pci_get_pdn_by_devfn(struct pci_bus *bus, >> if (pdev->devfn == devfn) { >> if (pdev->dev.archdata.pci_data) >> return pdev->dev.archdata.pci_data; >> - >> - dn = pci_device_to_OF_node(pdev); >> break; >> } >> } >> >> - /* Fast path: fetch from device node */ >> - pdn = dn ? PCI_DN(dn) : NULL; >> - if (pdn) >> - return pdn; >> - > > Why is it necessary to remove the above fast-path? >
It is not, actually - this had leaked from early stages of debugging, when I've found that after hotplug+rescan or hotplug+kexec the kernel took pdns from device nodes that do not represent the actual PCIe topology anymore. But after patches 3 and 4 the PCI_DN() is NULL for every PCIe device except root on PowerNV, so this block is safe. It will remain in version 3 of this patchset. >> /* Slow path: fetch from firmware data hierarchy */ >> parent = pci_bus_to_pdn(bus); >> if (!parent) >> @@ -128,16 +128,9 @@ struct pci_dn *pci_get_pdn(struct pci_dev *pdev) >> if (!parent) >> return NULL; >> >> - list_for_each_entry(pdn, &parent->child_list, list) { >> - if (pdn->busno == pdev->bus->number && >> - pdn->devfn == pdev->devfn) >> - return pdn; >> - } > > Could you explain why the above block was removed? Is it now impossible > for it to find a pdn? > I see now that this block was also removed too early: on PowerNV with this patchset it is impossible to have pdn being present in parent->child_list but not in pdev->dev.archdata.pci_data; but this may be not the case for pSeries. >> - >> - return NULL; >> + return create_pdn(pdev, parent); >> } >> >> -#ifdef CONFIG_PCI_IOV >> static struct pci_dn *add_one_dev_pci_data(struct pci_dn *parent, >> int vf_index, >> int busno, int devfn) >> @@ -156,7 +149,9 @@ static struct pci_dn *add_one_dev_pci_data(struct pci_dn >> *parent, >> pdn->parent = parent; >> pdn->busno = busno; >> pdn->devfn = devfn; >> + #ifdef CONFIG_PCI_IOV >> pdn->vf_index = vf_index; >> + #endif /* CONFIG_PCI_IOV */ >> pdn->pe_number = IODA_INVALID_PE; >> INIT_LIST_HEAD(&pdn->child_list); >> INIT_LIST_HEAD(&pdn->list); > > I can see that this change allows you to re-use this to set up a pdn in > create_pdn(). Perhaps you should refactor pci_add_device_node_info() to > use it as well, now that it's possible? > Sure, will do. >> @@ -164,7 +159,54 @@ static struct pci_dn *add_one_dev_pci_data(struct >> pci_dn *parent, >> >> return pdn; >> } >> -#endif >> + >> +static struct pci_dn *create_pdn(struct pci_dev *pdev, struct pci_dn >> *parent) >> +{ >> + struct pci_dn *pdn = NULL; >> + >> + pdn = add_one_dev_pci_data(parent, 0, pdev->bus->number, pdev->devfn); >> + dev_info(&pdev->dev, "Create a new pdn for devfn %2x\n", pdev->devfn / >> 8); >> + >> + if (pdn) { >> + #ifdef CONFIG_EEH >> + struct eeh_dev *edev; >> + #endif /* CONFIG_EEH */ >> + u32 class_code; >> + u16 device_id; >> + u16 vendor_id; >> + >> + #ifdef CONFIG_EEH >> + edev = eeh_dev_init(pdn); >> + if (!edev) { >> + kfree(pdn); >> + dev_err(&pdev->dev, "%s: Failed to allocate edev\n", >> __func__); >> + return NULL; >> + } >> + #endif /* CONFIG_EEH */ >> + >> + pdn->busno = pdev->bus->busn_res.start; > > It seems strange that pdn->busno is set by the call to > add_one_dev_pci_data() above (to pdev->bus->number) and then overwritten > here with a different value. Should add_one_dev_pci_data() use > pdev->bus->busn_res.start and this line be removed? > Thanks for capturing that! I'll prepare v3 with the fixes. >> + >> + pci_bus_read_config_word(pdev->bus, pdev->devfn, >> + PCI_VENDOR_ID, &vendor_id); >> + pdn->vendor_id = vendor_id; >> + >> + pci_bus_read_config_word(pdev->bus, pdev->devfn, >> + PCI_DEVICE_ID, &device_id); >> + pdn->device_id = device_id; >> + >> + pci_bus_read_config_dword(pdev->bus, pdev->devfn, >> + PCI_CLASS_REVISION, &class_code); >> + class_code >>= 8; >> + pdn->class_code = class_code; >> + >> + pdn->pci_ext_config_space = 0; >> + pdev->dev.archdata.pci_data = pdn; >> + } else { >> + dev_err(&pdev->dev, "%s: Failed to allocate pdn\n", __func__); >> + } >> + >> + return pdn; >> +} > > >> >> struct pci_dn *add_dev_pci_data(struct pci_dev *pdev) >> { >> -- >> 2.17.1 >> Best regards, Serge
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