[PATCH RFC 1/2] Implementation of pci_fixup_irqs for descendants of a specified bus
From: bhelgaas@google.com (Bjorn Helgaas)
Date: 2013-01-31 00:24:42
Also in:
linux-devicetree, linux-pci, linux-tegra, lkml
On Fri, Jan 18, 2013 at 4:37 AM, Andrew Murray [off-list ref] wrote:
Continuing from discussion with Thierry (lkml.org/lkml/2013/1/18/107) perhaps this will be useful to fold into your patchset. --- This patch provides pci_bus_fixup_irqs which performs the same function as pci_fixup_irqs but only to descendants of the specified bus.
I think pci_fixup_irqs() is a broken design to begin with because it is only called once at boot-time and it iterates over all the devices we've found so far. Any hot-added devices never get the fixups. Adding pci_bus_fixup_irqs() addresses part of that, by adding a way to fixup a subset of devices, e.g., maybe it could be done for hot-added things. But I think it would be better to do a more extensive refactoring and do the IRQ fixups directly somewhere in the pci_device_add() path. That way we can do it a device at a time, for every device (present at boot and hot-added later), and before any drivers claim the device.
quoted hunk ↗ jump to hunk
This can reduce unnecessary fixing up of device irqs when new buses are added. Signed-off-by: Andrew Murray <redacted> Signed-off-by: Liviu Dudau <Liviu.Dudau@arm.com> --- drivers/pci/setup-irq.c | 15 +++++++++++++++ include/linux/pci.h | 3 +++ 2 files changed, 18 insertions(+), 0 deletions(-)diff --git a/drivers/pci/setup-irq.c b/drivers/pci/setup-irq.c index eb219a1..ea91874 100644 --- a/drivers/pci/setup-irq.c +++ b/drivers/pci/setup-irq.c@@ -62,3 +62,18 @@ pci_fixup_irqs(u8 (*swizzle)(struct pci_dev *, u8 *), for_each_pci_dev(dev) pdev_fixup_irq(dev, swizzle, map_irq); } + +void __init +pci_bus_fixup_irqs(struct pci_bus *bus, + u8 (*swizzle)(struct pci_dev *, u8 *), + int (*map_irq)(const struct pci_dev *, u8, u8)) +{ + struct pci_dev *dev; + + list_for_each_entry(dev, &bus->devices, bus_list) { + pdev_fixup_irq(dev, swizzle, map_irq); + + if (dev->subordinate) + pci_bus_fixup_irqs(dev->subordinate, swizzle, map_irq); + } +}diff --git a/include/linux/pci.h b/include/linux/pci.h index 5faa831..1b3c2eb 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h@@ -953,6 +953,9 @@ void pdev_enable_device(struct pci_dev *); int pci_enable_resources(struct pci_dev *, int mask); void pci_fixup_irqs(u8 (*)(struct pci_dev *, u8 *), int (*)(const struct pci_dev *, u8, u8)); +void pci_bus_fixup_irqs(struct pci_bus *bus, + u8 (*swizzle)(struct pci_dev *, u8 *), + int (*map_irq)(const struct pci_dev *, u8, u8)); #define HAVE_PCI_REQ_REGIONS 2 int __must_check pci_request_regions(struct pci_dev *, const char *); int __must_check pci_request_regions_exclusive(struct pci_dev *, const char *); --1.7.0.4