LXR linux/arch/mips/pci/pci-generic.c

   1/*
   2 * Copyright (C) 2016 Imagination Technologies
   3 * Author: Paul Burton <paul.burton@imgtec.com>
   4 *
   5 * pcibios_align_resource taken from arch/arm/kernel/bios32.c.
   6 *
   7 * This program is free software; you can redistribute it and/or modify it
   8 * under the terms of the GNU General Public License as published by the
   9 * Free Software Foundation;  either version 2 of the  License, or (at your
  10 * option) any later version.
  11 */
  12
  13#include <linux/pci.h>
  14
  15/*
  16 * We need to avoid collisions with `mirrored' VGA ports
  17 * and other strange ISA hardware, so we always want the
  18 * addresses to be allocated in the 0x000-0x0ff region
  19 * modulo 0x400.
  20 *
  21 * Why? Because some silly external IO cards only decode
  22 * the low 10 bits of the IO address. The 0x00-0xff region
  23 * is reserved for motherboard devices that decode all 16
  24 * bits, so it's ok to allocate at, say, 0x2800-0x28ff,
  25 * but we want to try to avoid allocating at 0x2900-0x2bff
  26 * which might have be mirrored at 0x0100-0x03ff..
  27 */
  28resource_size_t pcibios_align_resource(void *data, const struct resource *res,
  29                                resource_size_t size, resource_size_t align)
  30{
  31        struct pci_dev *dev = data;
  32        resource_size_t start = res->start;
  33        struct pci_host_bridge *host_bridge;
  34
  35        if (res->flags & IORESOURCE_IO && start & 0x300)
  36                start = (start + 0x3ff) & ~0x3ff;
  37
  38        start = (start + align - 1) & ~(align - 1);
  39
  40        host_bridge = pci_find_host_bridge(dev->bus);
  41
  42        if (host_bridge->align_resource)
  43                return host_bridge->align_resource(dev, res,
  44                                start, size, align);
  45
  46        return start;
  47}
  48
  49void pcibios_fixup_bus(struct pci_bus *bus)
  50{
  51        pci_read_bridge_bases(bus);
  52}
  53