On 10/07/2015 12:44 PM, Bjorn Helgaas wrote:
Hi David,
On Fri, Oct 02, 2015 at 11:43:59AM -0700, David Daney wrote:
From: David Daney <[email protected]>
pci_bus_fixup_irqs() works like pci_fixup_irqs(), except it only does
the fixups for devices on the specified bus.
Follow-on patch will use the new function.
Signed-off-by: David Daney <[email protected]>
---
No change from v2.
drivers/pci/setup-irq.c | 30 ++++++++++++++++++++++++++++++
include/linux/pci.h | 4 ++++
2 files changed, 34 insertions(+)
diff --git a/drivers/pci/setup-irq.c b/drivers/pci/setup-irq.c
index 95c225b..189ad17 100644
--- a/drivers/pci/setup-irq.c
+++ b/drivers/pci/setup-irq.c
@@ -66,3 +66,33 @@ void pci_fixup_irqs(u8 (*swizzle)(struct pci_dev *, u8 *),
pdev_fixup_irq(dev, swizzle, map_irq);
}
EXPORT_SYMBOL_GPL(pci_fixup_irqs);
+
+struct pci_bus_fixup_cb_info {
+ u8 (*swizzle)(struct pci_dev *, u8 *);
+ int (*map_irq)(const struct pci_dev *, u8, u8);
+};
+
+static int pci_bus_fixup_irq_cb(struct pci_dev *dev, void *arg)
+{
+ struct pci_bus_fixup_cb_info *info = arg;
+
+ pdev_fixup_irq(dev, info->swizzle, info->map_irq);
+ return 0;
+}
+
+/*
+ * Fixup the irqs only for devices on the given bus using supplied
+ * swizzle and map_irq function pointers
+ */
+void 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_bus_fixup_cb_info info;
+
+ info.swizzle = swizzle;
+ info.map_irq = map_irq;
+ pci_walk_bus(bus, pci_bus_fixup_irq_cb, &info);
I don't like the existing pci_fixup_irqs(), so by transitivity, I
don't like pci_bus_fixup_irqs() either.
We are in agreement with respect to this point.
The problem is that in both
cases this is a one-time pass over the tree, so we don't handle
hot-added devices correctly.
I think we need to get rid of pci_fixup_irqs() and somehow integrate
it into the pci_device_add() path, where it would be done once for
every device we enumerate.
I also agree with this point.
If we did that, I don't think you would
need to add pci_bus_fixup_irqs(), would you?
Nope.
However, such a change is essentially untestable by me. So, I didn't
attempt it. pci_fixup_irqs() is used by alpha, arm, m68k, mips, sh,
sparc, tile, unicore32 and other things as well. If the core
pci_device_add() code were to suddenly start doing the fixup, there
would be the potential to break all these things I cannot test.
The new pci_bus_fixup_irqs() is really an optimization so that if we
have multiple buses created by pci-host-generic.c, that we only iterate
over each device once. I believe that pci-host-generic.c would still
operate without these patches 1/5 and 2/5, and could test that if you
are OK with the remaining three patches. Or we could merge all 5 and
live a while longer with the ugliness that is already there.
David Daney
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