| Message ID | 1314167063-15785-3-git-send-email-dengcheng.zhu@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Delegated to: | Bjorn Helgaas |
| Headers | show |
On Wed, Aug 24, 2011 at 12:24 AM, Deng-Cheng Zhu <dengcheng.zhu@gmail.com> wrote: > Currently, after pci_create_bus(), resources available on the bus could be > handled by pci_scan_child_bus(). The problem is that, in > pci_scan_child_bus(), before calling arch-dependent pcibios_fixup_bus(), > PCI quirks will probably conflict (while doing pci_claim_resource()) with > resources like system controller's I/O resource that have not yet been > added to the bus. So, add those resources right before returning the newly > created bus in pci_create_bus(). I like this approach a lot. Thanks for working it up. It's a nice small change with very little impact to other architectures, and you have a nice clear changelog. You might mention something about the fact that by default, the bus starts out with all of ioport_resource and iomem_resource -- that will mean something to people who know how host bridges work. > diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c > index 8473727..7735fe7 100644 > --- a/drivers/pci/probe.c > +++ b/drivers/pci/probe.c > @@ -1516,7 +1516,8 @@ unsigned int __devinit pci_scan_child_bus(struct pci_bus *bus) > } > > struct pci_bus * pci_create_bus(struct device *parent, > - int bus, struct pci_ops *ops, void *sysdata) > + int bus, struct pci_ops *ops, void *sysdata, > + struct pci_bus_resource *bus_res) > { > int error; > struct pci_bus *b, *b2; > @@ -1570,8 +1571,14 @@ struct pci_bus * pci_create_bus(struct device *parent, > pci_create_legacy_files(b); > > b->number = b->secondary = bus; > - b->resource[0] = &ioport_resource; > - b->resource[1] = &iomem_resource; > + > + /* Add initial resources to the bus */ > + if (bus_res != NULL) { > + list_add_tail(&b->resources, &bus_res->list); > + } else { > + pci_bus_add_resource(b, &ioport_resource, 0); > + pci_bus_add_resource(b, &iomem_resource, 0); > + } Using pci_bus_add_resource() here *seems* like it should be the right thing, but I don't think it will work correctly. The problem is that struct pci_bus has both a table of resources (bus->resource[]) *and* a list (bus->resources). pci_bus_add_resource() always puts the new resource on the list, but various arch code still references the table directly, e.g., sparc has "pbus->resource[0] = &pbm->io_space" in pcibios_fixup_bus(). As written, I think this patch will break sparc because the host bridge will end up with both pbm->io_space (in the table) and ioport_resource (in the list). I think something like this would work, though: if (bus_res) list_add_tail(&b->resources, &bus_res->list); else { b->resource[0] = &ioport_resource; b->resource[1] = &iomem_resource; } Bjorn -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
2011/8/24 Bjorn Helgaas <bhelgaas@google.com>: > I like this approach a lot. Thanks for working it up. It's a nice > small change with very little impact to other architectures, and you > have a nice clear changelog. You might mention something about the > fact that by default, the bus starts out with all of ioport_resource > and iomem_resource -- that will mean something to people who know how > host bridges work. Thanks! And I'll add this info to the patch description. > Using pci_bus_add_resource() here *seems* like it should be the right > thing, but I don't think it will work correctly. > > The problem is that struct pci_bus has both a table of resources > (bus->resource[]) *and* a list (bus->resources). > pci_bus_add_resource() always puts the new resource on the list, but > various arch code still references the table directly, e.g., sparc has > "pbus->resource[0] = &pbm->io_space" in pcibios_fixup_bus(). > > As written, I think this patch will break sparc because the host > bridge will end up with both pbm->io_space (in the table) and > ioport_resource (in the list). Good catch! I overlooked this point. > I think something like this would work, though: > > if (bus_res) > list_add_tail(&b->resources, &bus_res->list); > else { > b->resource[0] = &ioport_resource; > b->resource[1] = &iomem_resource; > } Yes, it should work. Thanks again for your time, Deng-Cheng -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/arch/microblaze/pci/pci-common.c b/arch/microblaze/pci/pci-common.c index 4cfae20..9c35aa6 100644 --- a/arch/microblaze/pci/pci-common.c +++ b/arch/microblaze/pci/pci-common.c @@ -1581,7 +1581,8 @@ static void __devinit pcibios_scan_phb(struct pci_controller *hose) node ? node->full_name : "<NO NAME>"); /* Create an empty bus for the toplevel */ - bus = pci_create_bus(hose->parent, hose->first_busno, hose->ops, hose); + bus = pci_create_bus(hose->parent, hose->first_busno, + hose->ops, hose, NULL); if (bus == NULL) { printk(KERN_ERR "Failed to create bus for PCI domain %04x\n", hose->global_number); diff --git a/arch/powerpc/kernel/pci-common.c b/arch/powerpc/kernel/pci-common.c index 32656f1..2ede26a 100644 --- a/arch/powerpc/kernel/pci-common.c +++ b/arch/powerpc/kernel/pci-common.c @@ -1703,7 +1703,8 @@ void __devinit pcibios_scan_phb(struct pci_controller *hose) node ? node->full_name : "<NO NAME>"); /* Create an empty bus for the toplevel */ - bus = pci_create_bus(hose->parent, hose->first_busno, hose->ops, hose); + bus = pci_create_bus(hose->parent, hose->first_busno, + hose->ops, hose, NULL); if (bus == NULL) { pr_err("Failed to create bus for PCI domain %04x\n", hose->global_number); diff --git a/arch/sparc/kernel/pci.c b/arch/sparc/kernel/pci.c index 1e94f94..77c38bb 100644 --- a/arch/sparc/kernel/pci.c +++ b/arch/sparc/kernel/pci.c @@ -689,7 +689,8 @@ struct pci_bus * __devinit pci_scan_one_pbm(struct pci_pbm_info *pbm, printk("PCI: Scanning PBM %s\n", node->full_name); - bus = pci_create_bus(parent, pbm->pci_first_busno, pbm->pci_ops, pbm); + bus = pci_create_bus(parent, pbm->pci_first_busno, + pbm->pci_ops, pbm, NULL); if (!bus) { printk(KERN_ERR "Failed to create bus for %s\n", node->full_name); diff --git a/arch/x86/pci/acpi.c b/arch/x86/pci/acpi.c index c953302..bab2113 100644 --- a/arch/x86/pci/acpi.c +++ b/arch/x86/pci/acpi.c @@ -353,7 +353,7 @@ struct pci_bus * __devinit pci_acpi_scan_root(struct acpi_pci_root *root) memcpy(bus->sysdata, sd, sizeof(*sd)); kfree(sd); } else { - bus = pci_create_bus(NULL, busnum, &pci_root_ops, sd); + bus = pci_create_bus(NULL, busnum, &pci_root_ops, sd, NULL); if (bus) { get_current_resources(device, busnum, domain, bus); bus->subordinate = pci_scan_child_bus(bus); diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c index 8473727..7735fe7 100644 --- a/drivers/pci/probe.c +++ b/drivers/pci/probe.c @@ -1516,7 +1516,8 @@ unsigned int __devinit pci_scan_child_bus(struct pci_bus *bus) } struct pci_bus * pci_create_bus(struct device *parent, - int bus, struct pci_ops *ops, void *sysdata) + int bus, struct pci_ops *ops, void *sysdata, + struct pci_bus_resource *bus_res) { int error; struct pci_bus *b, *b2; @@ -1570,8 +1571,14 @@ struct pci_bus * pci_create_bus(struct device *parent, pci_create_legacy_files(b); b->number = b->secondary = bus; - b->resource[0] = &ioport_resource; - b->resource[1] = &iomem_resource; + + /* Add initial resources to the bus */ + if (bus_res != NULL) { + list_add_tail(&b->resources, &bus_res->list); + } else { + pci_bus_add_resource(b, &ioport_resource, 0); + pci_bus_add_resource(b, &iomem_resource, 0); + } return b; @@ -1592,7 +1599,7 @@ struct pci_bus * __devinit pci_scan_bus_parented(struct device *parent, { struct pci_bus *b; - b = pci_create_bus(parent, bus, ops, sysdata); + b = pci_create_bus(parent, bus, ops, sysdata, NULL); if (b) b->subordinate = pci_scan_child_bus(b); return b; diff --git a/include/linux/pci.h b/include/linux/pci.h index 8c230cb..5e1bacd 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -666,7 +666,8 @@ static inline struct pci_bus * __devinit pci_scan_bus(int bus, struct pci_ops *o return root_bus; } struct pci_bus *pci_create_bus(struct device *parent, int bus, - struct pci_ops *ops, void *sysdata); + struct pci_ops *ops, void *sysdata, + struct pci_bus_resource *bus_res); struct pci_bus *pci_add_new_bus(struct pci_bus *parent, struct pci_dev *dev, int busnr); void pcie_update_link_speed(struct pci_bus *bus, u16 link_status);
Currently, after pci_create_bus(), resources available on the bus could be handled by pci_scan_child_bus(). The problem is that, in pci_scan_child_bus(), before calling arch-dependent pcibios_fixup_bus(), PCI quirks will probably conflict (while doing pci_claim_resource()) with resources like system controller's I/O resource that have not yet been added to the bus. So, add those resources right before returning the newly created bus in pci_create_bus(). A related discussion thread can be found here: http://www.spinics.net/lists/mips/msg41654.html Signed-off-by: Deng-Cheng Zhu <dengcheng.zhu@gmail.com> --- arch/microblaze/pci/pci-common.c | 3 ++- arch/powerpc/kernel/pci-common.c | 3 ++- arch/sparc/kernel/pci.c | 3 ++- arch/x86/pci/acpi.c | 2 +- drivers/pci/probe.c | 15 +++++++++++---- include/linux/pci.h | 3 ++- 6 files changed, 20 insertions(+), 9 deletions(-)