LXR linux/arch/xtensa/kernel/pci.c

   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 * arch/xtensa/kernel/pci.c
   4 *
   5 * PCI bios-type initialisation for PCI machines
   6 *
   7 * Copyright (C) 2001-2005 Tensilica Inc.
   8 *
   9 * Based largely on work from Cort (ppc/kernel/pci.c)
  10 * IO functions copied from sparc.
  11 *
  12 * Chris Zankel <chris@zankel.net>
  13 */
  14
  15#include <linux/kernel.h>
  16#include <linux/pci.h>
  17#include <linux/delay.h>
  18#include <linux/string.h>
  19#include <linux/init.h>
  20#include <linux/sched.h>
  21#include <linux/errno.h>
  22#include <linux/memblock.h>
  23
  24#include <asm/pci-bridge.h>
  25#include <asm/platform.h>
  26
  27/*
  28 * We need to avoid collisions with `mirrored' VGA ports
  29 * and other strange ISA hardware, so we always want the
  30 * addresses to be allocated in the 0x000-0x0ff region
  31 * modulo 0x400.
  32 *
  33 * Why? Because some silly external IO cards only decode
  34 * the low 10 bits of the IO address. The 0x00-0xff region
  35 * is reserved for motherboard devices that decode all 16
  36 * bits, so it's ok to allocate at, say, 0x2800-0x28ff,
  37 * but we want to try to avoid allocating at 0x2900-0x2bff
  38 * which might have be mirrored at 0x0100-0x03ff..
  39 */
  40resource_size_t
  41pcibios_align_resource(void *data, const struct resource *res,
  42                       resource_size_t size, resource_size_t align)
  43{
  44        struct pci_dev *dev = data;
  45        resource_size_t start = res->start;
  46
  47        if (res->flags & IORESOURCE_IO) {
  48                if (size > 0x100) {
  49                        pr_err("PCI: I/O Region %s/%d too large (%u bytes)\n",
  50                                        pci_name(dev), dev->resource - res,
  51                                        size);
  52                }
  53
  54                if (start & 0x300)
  55                        start = (start + 0x3ff) & ~0x3ff;
  56        }
  57
  58        return start;
  59}
  60
  61void pcibios_fixup_bus(struct pci_bus *bus)
  62{
  63        if (bus->parent) {
  64                /* This is a subordinate bridge */
  65                pci_read_bridge_bases(bus);
  66        }
  67}
  68
  69/*
  70 * Platform support for /proc/bus/pci/X/Y mmap()s.
  71 *  -- paulus.
  72 */
  73
  74int pci_iobar_pfn(struct pci_dev *pdev, int bar, struct vm_area_struct *vma)
  75{
  76        struct pci_controller *pci_ctrl = (struct pci_controller*) pdev->sysdata;
  77        resource_size_t ioaddr = pci_resource_start(pdev, bar);
  78
  79        if (!pci_ctrl)
  80                return -EINVAL;         /* should never happen */
  81
  82        /* Convert to an offset within this PCI controller */
  83        ioaddr -= (unsigned long)pci_ctrl->io_space.base;
  84
  85        vma->vm_pgoff += (ioaddr + pci_ctrl->io_space.start) >> PAGE_SHIFT;
  86        return 0;
  87}
  88