linux/arch/mn10300/unit-asb2305/pci-asb2305.c
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   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 */
  34void pcibios_align_resource(void *data, struct resource *res,
  35                            resource_size_t size, resource_size_t align)
  36{
  37#if 0
  38        struct pci_dev *dev = data;
  39
  40        printk(KERN_DEBUG
  41               "### PCIBIOS_ALIGN_RESOURCE(%s,,{%08lx-%08lx,%08lx},%lx)\n",
  42               pci_name(dev),
  43               res->start,
  44               res->end,
  45               res->flags,
  46               size
  47               );
  48#endif
  49
  50        if (res->flags & IORESOURCE_IO) {
  51                unsigned long start = res->start;
  52
  53                if (start & 0x300) {
  54                        start = (start + 0x3ff) & ~0x3ff;
  55                        res->start = start;
  56                }
  57        }
  58}
  59
  60
  61/*
  62 *  Handle resources of PCI devices.  If the world were perfect, we could
  63 *  just allocate all the resource regions and do nothing more.  It isn't.
  64 *  On the other hand, we cannot just re-allocate all devices, as it would
  65 *  require us to know lots of host bridge internals.  So we attempt to
  66 *  keep as much of the original configuration as possible, but tweak it
  67 *  when it's found to be wrong.
  68 *
  69 *  Known BIOS problems we have to work around:
  70 *      - I/O or memory regions not configured
  71 *      - regions configured, but not enabled in the command register
  72 *      - bogus I/O addresses above 64K used
  73 *      - expansion ROMs left enabled (this may sound harmless, but given
  74 *        the fact the PCI specs explicitly allow address decoders to be
  75 *        shared between expansion ROMs and other resource regions, it's
  76 *        at least dangerous)
  77 *
  78 *  Our solution:
  79 *      (1) Allocate resources for all buses behind PCI-to-PCI bridges.
  80 *          This gives us fixed barriers on where we can allocate.
  81 *      (2) Allocate resources for all enabled devices.  If there is
  82 *          a collision, just mark the resource as unallocated. Also
  83 *          disable expansion ROMs during this step.
  84 *      (3) Try to allocate resources for disabled devices.  If the
  85 *          resources were assigned correctly, everything goes well,
  86 *          if they weren't, they won't disturb allocation of other
  87 *          resources.
  88 *      (4) Assign new addresses to resources which were either
  89 *          not configured at all or misconfigured.  If explicitly
  90 *          requested by the user, configure expansion ROM address
  91 *          as well.
  92 */
  93static void __init pcibios_allocate_bus_resources(struct list_head *bus_list)
  94{
  95        struct pci_bus *bus;
  96        struct pci_dev *dev;
  97        int idx;
  98        struct resource *r, *pr;
  99
 100        /* Depth-First Search on bus tree */
 101        list_for_each_entry(bus, bus_list, node) {
 102                dev = bus->self;
 103                if (dev) {
 104                        for (idx = PCI_BRIDGE_RESOURCES;
 105                             idx < PCI_NUM_RESOURCES;
 106                             idx++) {
 107                                r = &dev->resource[idx];
 108                                if (!r->flags)
 109                                        continue;
 110                                pr = pci_find_parent_resource(dev, r);
 111                                if (!r->start ||
 112                                    !pr ||
 113                                    request_resource(pr, r) < 0) {
 114                                        printk(KERN_ERR "PCI:"
 115                                               " Cannot allocate resource"
 116                                               " region %d of bridge %s\n",
 117                                               idx, pci_name(dev));
 118                                        /* Something is wrong with the region.
 119                                         * Invalidate the resource to prevent
 120                                         * child resource allocations in this
 121                                         * range. */
 122                                        r->flags = 0;
 123                                }
 124                        }
 125                }
 126                pcibios_allocate_bus_resources(&bus->children);
 127        }
 128}
 129
 130static void __init pcibios_allocate_resources(int pass)
 131{
 132        struct pci_dev *dev = NULL;
 133        int idx, disabled;
 134        u16 command;
 135        struct resource *r, *pr;
 136
 137        for_each_pci_dev(dev) {
 138                pci_read_config_word(dev, PCI_COMMAND, &command);
 139                for (idx = 0; idx < 6; idx++) {
 140                        r = &dev->resource[idx];
 141                        if (r->parent)          /* Already allocated */
 142                                continue;
 143                        if (!r->start)          /* Address not assigned */
 144                                continue;
 145                        if (r->flags & IORESOURCE_IO)
 146                                disabled = !(command & PCI_COMMAND_IO);
 147                        else
 148                                disabled = !(command & PCI_COMMAND_MEMORY);
 149                        if (pass == disabled) {
 150                                DBG("PCI[%s]: Resource %08lx-%08lx"
 151                                    " (f=%lx, d=%d, p=%d)\n",
 152                                    pci_name(dev), r->start, r->end, r->flags,
 153                                    disabled, pass);
 154                                pr = pci_find_parent_resource(dev, r);
 155                                if (!pr || request_resource(pr, r) < 0) {
 156                                        printk(KERN_ERR "PCI:"
 157                                               " Cannot allocate resource"
 158                                               " region %d of device %s\n",
 159                                               idx, pci_name(dev));
 160                                        /* We'll assign a new address later */
 161                                        r->end -= r->start;
 162                                        r->start = 0;
 163                                }
 164                        }
 165                }
 166                if (!pass) {
 167                        r = &dev->resource[PCI_ROM_RESOURCE];
 168                        if (r->flags & IORESOURCE_ROM_ENABLE) {
 169                                /* Turn the ROM off, leave the resource region,
 170                                 * but keep it unregistered. */
 171                                u32 reg;
 172                                DBG("PCI: Switching off ROM of %s\n",
 173                                    pci_name(dev));
 174                                r->flags &= ~IORESOURCE_ROM_ENABLE;
 175                                pci_read_config_dword(
 176                                        dev, dev->rom_base_reg, &reg);
 177                                pci_write_config_dword(
 178                                        dev, dev->rom_base_reg,
 179                                        reg & ~PCI_ROM_ADDRESS_ENABLE);
 180                        }
 181                }
 182        }
 183}
 184
 185static int __init pcibios_assign_resources(void)
 186{
 187        struct pci_dev *dev = NULL;
 188        struct resource *r, *pr;
 189
 190        if (!(pci_probe & PCI_ASSIGN_ROMS)) {
 191                /* Try to use BIOS settings for ROMs, otherwise let
 192                   pci_assign_unassigned_resources() allocate the new
 193                   addresses. */
 194                for_each_pci_dev(dev) {
 195                        r = &dev->resource[PCI_ROM_RESOURCE];
 196                        if (!r->flags || !r->start)
 197                                continue;
 198                        pr = pci_find_parent_resource(dev, r);
 199                        if (!pr || request_resource(pr, r) < 0) {
 200                                r->end -= r->start;
 201                                r->start = 0;
 202                        }
 203                }
 204        }
 205
 206        pci_assign_unassigned_resources();
 207
 208        return 0;
 209}
 210
 211fs_initcall(pcibios_assign_resources);
 212
 213void __init pcibios_resource_survey(void)
 214{
 215        DBG("PCI: Allocating resources\n");
 216        pcibios_allocate_bus_resources(&pci_root_buses);
 217        pcibios_allocate_resources(0);
 218        pcibios_allocate_resources(1);
 219}
 220
 221int pcibios_enable_resources(struct pci_dev *dev, int mask)
 222{
 223        u16 cmd, old_cmd;
 224        int idx;
 225        struct resource *r;
 226
 227        pci_read_config_word(dev, PCI_COMMAND, &cmd);
 228        old_cmd = cmd;
 229
 230        for (idx = 0; idx < 6; idx++) {
 231                /* Only set up the requested stuff */
 232                if (!(mask & (1 << idx)))
 233                        continue;
 234
 235                r = &dev->resource[idx];
 236
 237                if (!r->start && r->end) {
 238                        printk(KERN_ERR
 239                               "PCI: Device %s not available because of"
 240                               " resource collisions\n",
 241                               pci_name(dev));
 242                        return -EINVAL;
 243                }
 244
 245                if (r->flags & IORESOURCE_IO)
 246                        cmd |= PCI_COMMAND_IO;
 247                if (r->flags & IORESOURCE_MEM)
 248                        cmd |= PCI_COMMAND_MEMORY;
 249        }
 250
 251        if (dev->resource[PCI_ROM_RESOURCE].start)
 252                cmd |= PCI_COMMAND_MEMORY;
 253
 254        if (cmd != old_cmd)
 255                pci_write_config_word(dev, PCI_COMMAND, cmd);
 256
 257        return 0;
 258}
 259
 260/*
 261 *  If we set up a device for bus mastering, we need to check the latency
 262 *  timer as certain crappy BIOSes forget to set it properly.
 263 */
 264unsigned int pcibios_max_latency = 255;
 265
 266void pcibios_set_master(struct pci_dev *dev)
 267{
 268        u8 lat;
 269
 270        pci_read_config_byte(dev, PCI_LATENCY_TIMER, &lat);
 271
 272        if (lat < 16)
 273                lat = (64 <= pcibios_max_latency) ? 64 : pcibios_max_latency;
 274        else if (lat > pcibios_max_latency)
 275                lat = pcibios_max_latency;
 276        else
 277                return;
 278
 279        pci_write_config_byte(dev, PCI_LATENCY_TIMER, lat);
 280}
 281
 282int pci_mmap_page_range(struct pci_dev *dev, struct vm_area_struct *vma,
 283                        enum pci_mmap_state mmap_state, int write_combine)
 284{
 285        unsigned long prot;
 286
 287        /* Leave vm_pgoff as-is, the PCI space address is the physical
 288         * address on this platform.
 289         */
 290        vma->vm_flags |= VM_LOCKED | VM_IO;
 291
 292        prot = pgprot_val(vma->vm_page_prot);
 293        prot &= ~_PAGE_CACHE;
 294        vma->vm_page_prot = __pgprot(prot);
 295
 296        /* Write-combine setting is ignored */
 297        if (io_remap_pfn_range(vma, vma->vm_start, vma->vm_pgoff,
 298                               vma->vm_end - vma->vm_start,
 299                               vma->vm_page_prot))
 300                return -EAGAIN;
 301
 302        return 0;
 303}
 304