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  */
  40 resource_size_t
  41 pcibios_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
  61 void 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
  74 int 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 == 0)
  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 }