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ARM/PCI: Remove pci_fixup_irqs() call for bios32 host controllers

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Legacy PCI host controllers (ie host controllers that set-up the PCI bus
through the ARM pci_common_init() API) are currently relying on
pci_fixup_irqs() to assign legacy PCI irqs to devices.  This is not ideal
in that pci_fixup_irqs() assigns IRQs for all PCI devices present in a given
system some of which may well be enabled by the time pci_fixup_irqs() is
called (ie a system with multiple host controllers).  With the introduction
of struct pci_host_bridge.(*map_irq) pointer it is possible to assign IRQs
for all devices originating from a PCI host bridge at probe time; this is
implemented through pci_assign_irq() that relies on the struct
pci_host_bridge.map_irq pointer to map IRQ for a given device.

The benefits this brings are twofold:

  - the IRQ for a device is assigned once at probe time
  - the IRQ assignment works also for hotplugged devices

Remove pci_fixup_irqs() call from bios32 code and rely on pci_assign_irq()
to carry out the IRQ mapping at device probe time.

The map_irq() and swizzle_irq() struct pci_host_bridge callbacks are set-up
in the struct pci_host_bridge created in the bios32 pcibios_init_hw()
function and mach-* code paths (for PCI mach implementations that require a
specific struct hw_pci.(*scan) function callback).

Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
[bhelgaas: folded in fixes from Lorenzo:
http://lkml.kernel.org/r/20170701140629.GC8977@red-moon]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Andrew Lunn <andrew@lunn.ch>
This commit is contained in:
Lorenzo Pieralisi 2017-06-28 15:14:04 -05:00 committed by Bjorn Helgaas
parent 30fdfb929e
commit 16508469c0
1 changed files with 3 additions and 2 deletions
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5
arch/arm/kernel/bios32.c
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@ -484,6 +484,9 @@ static void pcibios_init_hw(struct device *parent, struct hw_pci *hw,
break;
}
bridge->map_irq = pcibios_map_irq;
bridge->swizzle_irq = pcibios_swizzle;
if (hw->scan)
ret = hw->scan(nr, bridge);
else {
@ -530,8 +533,6 @@ void pci_common_init_dev(struct device *parent, struct hw_pci *hw)
if (hw->postinit)
hw->postinit();
pci_fixup_irqs(pcibios_swizzle, pcibios_map_irq);
list_for_each_entry(sys, &head, node) {
struct pci_bus *bus = sys->bus;