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https://github.com/torvalds/linux
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8885b7b637
Most architectures implement this in exactly the same way. Instead of having each architecture duplicate this function, provide a single implementation in the core and make it a weak symbol so that it can be overridden on architectures where it is required. Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
69 lines
1.7 KiB
C
69 lines
1.7 KiB
C
/*
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* drivers/pci/setup-irq.c
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*
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* Extruded from code written by
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* Dave Rusling (david.rusling@reo.mts.dec.com)
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* David Mosberger (davidm@cs.arizona.edu)
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* David Miller (davem@redhat.com)
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*
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* Support routines for initializing a PCI subsystem.
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*/
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/pci.h>
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#include <linux/errno.h>
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#include <linux/ioport.h>
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#include <linux/cache.h>
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void __weak pcibios_update_irq(struct pci_dev *dev, int irq)
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{
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dev_dbg(&dev->dev, "assigning IRQ %02d\n", irq);
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pci_write_config_byte(dev, PCI_INTERRUPT_LINE, irq);
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}
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static void
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pdev_fixup_irq(struct pci_dev *dev,
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u8 (*swizzle)(struct pci_dev *, u8 *),
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int (*map_irq)(const struct pci_dev *, u8, u8))
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{
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u8 pin, slot;
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int irq = 0;
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/* If this device is not on the primary bus, we need to figure out
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which interrupt pin it will come in on. We know which slot it
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will come in on 'cos that slot is where the bridge is. Each
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time the interrupt line passes through a PCI-PCI bridge we must
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apply the swizzle function. */
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pci_read_config_byte(dev, PCI_INTERRUPT_PIN, &pin);
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/* Cope with illegal. */
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if (pin > 4)
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pin = 1;
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if (pin != 0) {
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/* Follow the chain of bridges, swizzling as we go. */
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slot = (*swizzle)(dev, &pin);
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irq = (*map_irq)(dev, slot, pin);
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if (irq == -1)
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irq = 0;
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}
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dev->irq = irq;
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dev_dbg(&dev->dev, "fixup irq: got %d\n", dev->irq);
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/* Always tell the device, so the driver knows what is
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the real IRQ to use; the device does not use it. */
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pcibios_update_irq(dev, irq);
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}
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void
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pci_fixup_irqs(u8 (*swizzle)(struct pci_dev *, u8 *),
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int (*map_irq)(const struct pci_dev *, u8, u8))
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{
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struct pci_dev *dev = NULL;
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for_each_pci_dev(dev)
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pdev_fixup_irq(dev, swizzle, map_irq);
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}
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