LXR linux/arch/mn10300/unit-asb2305/pci-asb2305.c

   1/* ASB2305 PCI resource stuff
   2 *
   3 * Copyright (C) 2001 Red Hat, Inc. All Rights Reserved.
   4 * Written by David Howells (dhowells@redhat.com)
   5 * - Derived from arch/i386/pci-i386.c
   6 *   - Copyright 1997--2000 Martin Mares <mj@suse.cz>
   7 *
   8 * This program is free software; you can redistribute it and/or
   9 * modify it under the terms of the GNU General Public Licence
  10 * as published by the Free Software Foundation; either version
  11 * 2 of the Licence, or (at your option) any later version.
  12 */
  13#include <linux/types.h>
  14#include <linux/kernel.h>
  15#include <linux/pci.h>
  16#include <linux/init.h>
  17#include <linux/ioport.h>
  18#include <linux/errno.h>
  19#include "pci-asb2305.h"
  20
  21/*
  22 * We need to avoid collisions with `mirrored' VGA ports
  23 * and other strange ISA hardware, so we always want the
  24 * addresses to be allocated in the 0x000-0x0ff region
  25 * modulo 0x400.
  26 *
  27 * Why? Because some silly external IO cards only decode
  28 * the low 10 bits of the IO address. The 0x00-0xff region
  29 * is reserved for motherboard devices that decode all 16
  30 * bits, so it's ok to allocate at, say, 0x2800-0x28ff,
  31 * but we want to try to avoid allocating at 0x2900-0x2bff
  32 * which might have be mirrored at 0x0100-0x03ff..
  33 */
  34resource_size_t pcibios_align_resource(void *data, const struct resource *res,
  35                                resource_size_t size, resource_size_t align)
  36{
  37        resource_size_t start = res->start;
  38
  39#if 0
  40        struct pci_dev *dev = data;
  41
  42        printk(KERN_DEBUG
  43               "### PCIBIOS_ALIGN_RESOURCE(%s,,{%08lx-%08lx,%08lx},%lx)\n",
  44               pci_name(dev),
  45               res->start,
  46               res->end,
  47               res->flags,
  48               size
  49               );
  50#endif
  51
  52        if ((res->flags & IORESOURCE_IO) && (start & 0x300))
  53                start = (start + 0x3ff) & ~0x3ff;
  54
  55        return start;
  56}
  57
  58
  59/*
  60 *  Handle resources of PCI devices.  If the world were perfect, we could
  61 *  just allocate all the resource regions and do nothing more.  It isn't.
  62 *  On the other hand, we cannot just re-allocate all devices, as it would
  63 *  require us to know lots of host bridge internals.  So we attempt to
  64 *  keep as much of the original configuration as possible, but tweak it
  65 *  when it's found to be wrong.
  66 *
  67 *  Known BIOS problems we have to work around:
  68 *      - I/O or memory regions not configured
  69 *      - regions configured, but not enabled in the command register
  70 *      - bogus I/O addresses above 64K used
  71 *      - expansion ROMs left enabled (this may sound harmless, but given
  72 *        the fact the PCI specs explicitly allow address decoders to be
  73 *        shared between expansion ROMs and other resource regions, it's
  74 *        at least dangerous)
  75 *
  76 *  Our solution:
  77 *      (1) Allocate resources for all buses behind PCI-to-PCI bridges.
  78 *          This gives us fixed barriers on where we can allocate.
  79 *      (2) Allocate resources for all enabled devices.  If there is
  80 *          a collision, just mark the resource as unallocated. Also
  81 *          disable expansion ROMs during this step.
  82 *      (3) Try to allocate resources for disabled devices.  If the
  83 *          resources were assigned correctly, everything goes well,
  84 *          if they weren't, they won't disturb allocation of other
  85 *          resources.
  86 *      (4) Assign new addresses to resources which were either
  87 *          not configured at all or misconfigured.  If explicitly
  88 *          requested by the user, configure expansion ROM address
  89 *          as well.
  90 */
  91static void __init pcibios_allocate_bus_resources(struct list_head *bus_list)
  92{
  93        struct pci_bus *bus;
  94        struct pci_dev *dev;
  95        int idx;
  96        struct resource *r;
  97
  98        /* Depth-First Search on bus tree */
  99        list_for_each_entry(bus, bus_list, node) {
 100                dev = bus->self;
 101                if (dev) {
 102                        for (idx = PCI_BRIDGE_RESOURCES;
 103                             idx < PCI_NUM_RESOURCES;
 104                             idx++) {
 105                                r = &dev->resource[idx];
 106                                if (!r->flags)
 107                                        continue;
 108                                if (!r->start ||
 109                                    pci_claim_bridge_resource(dev, idx) < 0) {
 110                                        printk(KERN_ERR "PCI:"
 111                                               " Cannot allocate resource"
 112                                               " region %d of bridge %s\n",
 113                                               idx, pci_name(dev));
 114                                        /* Something is wrong with the region.
 115                                         * Invalidate the resource to prevent
 116                                         * child resource allocations in this
 117                                         * range. */
 118                                        r->start = r->end = 0;
 119                                        r->flags = 0;
 120                                }
 121                        }
 122                }
 123                pcibios_allocate_bus_resources(&bus->children);
 124        }
 125}
 126
 127static void __init pcibios_allocate_resources(int pass)
 128{
 129        struct pci_dev *dev = NULL;
 130        int idx, disabled;
 131        u16 command;
 132        struct resource *r;
 133
 134        for_each_pci_dev(dev) {
 135                pci_read_config_word(dev, PCI_COMMAND, &command);
 136                for (idx = 0; idx < 6; idx++) {
 137                        r = &dev->resource[idx];
 138                        if (r->parent)          /* Already allocated */
 139                                continue;
 140                        if (!r->start)          /* Address not assigned */
 141                                continue;
 142                        if (r->flags & IORESOURCE_IO)
 143                                disabled = !(command & PCI_COMMAND_IO);
 144                        else
 145                                disabled = !(command & PCI_COMMAND_MEMORY);
 146                        if (pass == disabled) {
 147                                DBG("PCI[%s]: Resource %08lx-%08lx"
 148                                    " (f=%lx, d=%d, p=%d)\n",
 149                                    pci_name(dev), r->start, r->end, r->flags,
 150                                    disabled, pass);
 151                                if (pci_claim_resource(dev, idx) < 0) {
 152                                        printk(KERN_ERR "PCI:"
 153                                               " Cannot allocate resource"
 154                                               " region %d of device %s\n",
 155                                               idx, pci_name(dev));
 156                                        /* We'll assign a new address later */
 157                                        r->end -= r->start;
 158                                        r->start = 0;
 159                                }
 160                        }
 161                }
 162                if (!pass) {
 163                        r = &dev->resource[PCI_ROM_RESOURCE];
 164                        if (r->flags & IORESOURCE_ROM_ENABLE) {
 165                                /* Turn the ROM off, leave the resource region,
 166                                 * but keep it unregistered. */
 167                                u32 reg;
 168                                DBG("PCI: Switching off ROM of %s\n",
 169                                    pci_name(dev));
 170                                r->flags &= ~IORESOURCE_ROM_ENABLE;
 171                                pci_read_config_dword(
 172                                        dev, dev->rom_base_reg, &reg);
 173                                pci_write_config_dword(
 174                                        dev, dev->rom_base_reg,
 175                                        reg & ~PCI_ROM_ADDRESS_ENABLE);
 176                        }
 177                }
 178        }
 179}
 180
 181static int __init pcibios_assign_resources(void)
 182{
 183        struct pci_dev *dev = NULL;
 184        struct resource *r;
 185
 186        /* Try to use BIOS settings for ROMs, otherwise let
 187           pci_assign_unassigned_resources() allocate the new
 188           addresses. */
 189        for_each_pci_dev(dev) {
 190                r = &dev->resource[PCI_ROM_RESOURCE];
 191                if (!r->flags || !r->start)
 192                        continue;
 193                if (pci_claim_resource(dev, PCI_ROM_RESOURCE) < 0) {
 194                        r->end -= r->start;
 195                        r->start = 0;
 196                }
 197        }
 198
 199        pci_assign_unassigned_resources();
 200
 201        return 0;
 202}
 203
 204fs_initcall(pcibios_assign_resources);
 205
 206void __init pcibios_resource_survey(void)
 207{
 208        DBG("PCI: Allocating resources\n");
 209        pcibios_allocate_bus_resources(&pci_root_buses);
 210        pcibios_allocate_resources(0);
 211        pcibios_allocate_resources(1);
 212}
 213
 214int pci_mmap_page_range(struct pci_dev *dev, struct vm_area_struct *vma,
 215                        enum pci_mmap_state mmap_state, int write_combine)
 216{
 217        unsigned long prot;
 218
 219        /* Leave vm_pgoff as-is, the PCI space address is the physical
 220         * address on this platform.
 221         */
 222        vma->vm_flags |= VM_LOCKED;
 223
 224        prot = pgprot_val(vma->vm_page_prot);
 225        prot &= ~_PAGE_CACHE;
 226        vma->vm_page_prot = __pgprot(prot);
 227
 228        /* Write-combine setting is ignored */
 229        if (io_remap_pfn_range(vma, vma->vm_start, vma->vm_pgoff,
 230                               vma->vm_end - vma->vm_start,
 231                               vma->vm_page_prot))
 232                return -EAGAIN;
 233
 234        return 0;
 235}
 236