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  */
  34 resource_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  */
  91 static 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
 127 static 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
 181 static 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
 204 fs_initcall(pcibios_assign_resources);
 205
 206 void __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 }