arch/x86/pci/i386.c

   1 /*
   2  *      Low-Level PCI Access for i386 machines
   3  *
   4  * Copyright 1993, 1994 Drew Eckhardt
   5  *      Visionary Computing
   6  *      (Unix and Linux consulting and custom programming)
   7  *      Drew@Colorado.EDU
   8  *      +1 (303) 786-7975
   9  *
  10  * Drew's work was sponsored by:
  11  *      iX Multiuser Multitasking Magazine
  12  *      Hannover, Germany
  13  *      hm@ix.de
  14  *
  15  * Copyright 1997--2000 Martin Mares <mj@ucw.cz>
  16  *
  17  * For more information, please consult the following manuals (look at
  18  * http://www.pcisig.com/ for how to get them):
  19  *
  20  * PCI BIOS Specification
  21  * PCI Local Bus Specification
  22  * PCI to PCI Bridge Specification
  23  * PCI System Design Guide
  24  *
  25  */
  26
  27 #include <linux/types.h>
  28 #include <linux/kernel.h>
  29 #include <linux/pci.h>
  30 #include <linux/init.h>
  31 #include <linux/ioport.h>
  32 #include <linux/errno.h>
  33 #include <linux/bootmem.h>
  34
  35 #include <asm/pat.h>
  36
  37 #include "pci.h"
  38
  39 static int
  40 skip_isa_ioresource_align(struct pci_dev *dev) {
  41
  42         if ((pci_probe & PCI_CAN_SKIP_ISA_ALIGN) &&
  43             !(dev->bus->bridge_ctl & PCI_BRIDGE_CTL_ISA))
  44                 return 1;
  45         return 0;
  46 }
  47
  48 /*
  49  * We need to avoid collisions with `mirrored' VGA ports
  50  * and other strange ISA hardware, so we always want the
  51  * addresses to be allocated in the 0x000-0x0ff region
  52  * modulo 0x400.
  53  *
  54  * Why? Because some silly external IO cards only decode
  55  * the low 10 bits of the IO address. The 0x00-0xff region
  56  * is reserved for motherboard devices that decode all 16
  57  * bits, so it's ok to allocate at, say, 0x2800-0x28ff,
  58  * but we want to try to avoid allocating at 0x2900-0x2bff
  59  * which might have be mirrored at 0x0100-0x03ff..
  60  */
  61 void
  62 pcibios_align_resource(void *data, struct resource *res,
  63                         resource_size_t size, resource_size_t align)
  64 {
  65         struct pci_dev *dev = data;
  66
  67         if (res->flags & IORESOURCE_IO) {
  68                 resource_size_t start = res->start;
  69
  70                 if (skip_isa_ioresource_align(dev))
  71                         return;
  72                 if (start & 0x300) {
  73                         start = (start + 0x3ff) & ~0x3ff;
  74                         res->start = start;
  75                 }
  76         }
  77 }
  78 EXPORT_SYMBOL(pcibios_align_resource);
  79
  80 /*
  81  *  Handle resources of PCI devices.  If the world were perfect, we could
  82  *  just allocate all the resource regions and do nothing more.  It isn't.
  83  *  On the other hand, we cannot just re-allocate all devices, as it would
  84  *  require us to know lots of host bridge internals.  So we attempt to
  85  *  keep as much of the original configuration as possible, but tweak it
  86  *  when it's found to be wrong.
  87  *
  88  *  Known BIOS problems we have to work around:
  89  *      - I/O or memory regions not configured
  90  *      - regions configured, but not enabled in the command register
  91  *      - bogus I/O addresses above 64K used
  92  *      - expansion ROMs left enabled (this may sound harmless, but given
  93  *        the fact the PCI specs explicitly allow address decoders to be
  94  *        shared between expansion ROMs and other resource regions, it's
  95  *        at least dangerous)
  96  *
  97  *  Our solution:
  98  *      (1) Allocate resources for all buses behind PCI-to-PCI bridges.
  99  *          This gives us fixed barriers on where we can allocate.
 100  *      (2) Allocate resources for all enabled devices.  If there is
 101  *          a collision, just mark the resource as unallocated. Also
 102  *          disable expansion ROMs during this step.
 103  *      (3) Try to allocate resources for disabled devices.  If the
 104  *          resources were assigned correctly, everything goes well,
 105  *          if they weren't, they won't disturb allocation of other
 106  *          resources.
 107  *      (4) Assign new addresses to resources which were either
 108  *          not configured at all or misconfigured.  If explicitly
 109  *          requested by the user, configure expansion ROM address
 110  *          as well.
 111  */
 112
 113 static void __init pcibios_allocate_bus_resources(struct list_head *bus_list)
 114 {
 115         struct pci_bus *bus;
 116         struct pci_dev *dev;
 117         int idx;
 118         struct resource *r, *pr;
 119
 120         /* Depth-First Search on bus tree */
 121         list_for_each_entry(bus, bus_list, node) {
 122                 if ((dev = bus->self)) {
 123                         for (idx = PCI_BRIDGE_RESOURCES;
 124                             idx < PCI_NUM_RESOURCES; idx++) {
 125                                 r = &dev->resource[idx];
 126                                 if (!r->flags)
 127                                         continue;
 128                                 pr = pci_find_parent_resource(dev, r);
 129                                 if (!r->start || !pr ||
 130                                     request_resource(pr, r) < 0) {
 131                                         printk(KERN_ERR "PCI: Cannot allocate "
 132                                                 "resource region %d "
 133                                                 "of bridge %s\n",
 134                                                 idx, pci_name(dev));
 135                                         /*
 136                                          * Something is wrong with the region.
 137                                          * Invalidate the resource to prevent
 138                                          * child resource allocations in this
 139                                          * range.
 140                                          */
 141                                         r->flags = 0;
 142                                 }
 143                         }
 144                 }
 145                 pcibios_allocate_bus_resources(&bus->children);
 146         }
 147 }
 148
 149 static void __init pcibios_allocate_resources(int pass)
 150 {
 151         struct pci_dev *dev = NULL;
 152         int idx, disabled;
 153         u16 command;
 154         struct resource *r, *pr;
 155
 156         for_each_pci_dev(dev) {
 157                 pci_read_config_word(dev, PCI_COMMAND, &command);
 158                 for (idx = 0; idx < PCI_ROM_RESOURCE; idx++) {
 159                         r = &dev->resource[idx];
 160                         if (r->parent)          /* Already allocated */
 161                                 continue;
 162                         if (!r->start)          /* Address not assigned at all */
 163                                 continue;
 164                         if (r->flags & IORESOURCE_IO)
 165                                 disabled = !(command & PCI_COMMAND_IO);
 166                         else
 167                                 disabled = !(command & PCI_COMMAND_MEMORY);
 168                         if (pass == disabled) {
 169                                 DBG("PCI: Resource %08lx-%08lx "
 170                                     "(f=%lx, d=%d, p=%d)\n",
 171                                     r->start, r->end, r->flags, disabled, pass);
 172                                 pr = pci_find_parent_resource(dev, r);
 173                                 if (!pr || request_resource(pr, r) < 0) {
 174                                         printk(KERN_ERR "PCI: Cannot allocate "
 175                                                 "resource region %d "
 176                                                 "of device %s\n",
 177                                                 idx, pci_name(dev));
 178                                         /* We'll assign a new address later */
 179                                         r->end -= r->start;
 180                                         r->start = 0;
 181                                 }
 182                         }
 183                 }
 184                 if (!pass) {
 185                         r = &dev->resource[PCI_ROM_RESOURCE];
 186                         if (r->flags & IORESOURCE_ROM_ENABLE) {
 187                                 /* Turn the ROM off, leave the resource region,
 188                                  * but keep it unregistered. */
 189                                 u32 reg;
 190                                 DBG("PCI: Switching off ROM of %s\n",
 191                                         pci_name(dev));
 192                                 r->flags &= ~IORESOURCE_ROM_ENABLE;
 193                                 pci_read_config_dword(dev,
 194                                                 dev->rom_base_reg, &reg);
 195                                 pci_write_config_dword(dev, dev->rom_base_reg,
 196                                                 reg & ~PCI_ROM_ADDRESS_ENABLE);
 197                         }
 198                 }
 199         }
 200 }
 201
 202 static int __init pcibios_assign_resources(void)
 203 {
 204         struct pci_dev *dev = NULL;
 205         struct resource *r, *pr;
 206
 207         if (!(pci_probe & PCI_ASSIGN_ROMS)) {
 208                 /*
 209                  * Try to use BIOS settings for ROMs, otherwise let
 210                  * pci_assign_unassigned_resources() allocate the new
 211                  * addresses.
 212                  */
 213                 for_each_pci_dev(dev) {
 214                         r = &dev->resource[PCI_ROM_RESOURCE];
 215                         if (!r->flags || !r->start)
 216                                 continue;
 217                         pr = pci_find_parent_resource(dev, r);
 218                         if (!pr || request_resource(pr, r) < 0) {
 219                                 r->end -= r->start;
 220                                 r->start = 0;
 221                         }
 222                 }
 223         }
 224
 225         pci_assign_unassigned_resources();
 226
 227         return 0;
 228 }
 229
 230 void __init pcibios_resource_survey(void)
 231 {
 232         DBG("PCI: Allocating resources\n");
 233         pcibios_allocate_bus_resources(&pci_root_buses);
 234         pcibios_allocate_resources(0);
 235         pcibios_allocate_resources(1);
 236 }
 237
 238 /**
 239  * called in fs_initcall (one below subsys_initcall),
 240  * give a chance for motherboard reserve resources
 241  */
 242 fs_initcall(pcibios_assign_resources);
 243
 244 /*
 245  *  If we set up a device for bus mastering, we need to check the latency
 246  *  timer as certain crappy BIOSes forget to set it properly.
 247  */
 248 unsigned int pcibios_max_latency = 255;
 249
 250 void pcibios_set_master(struct pci_dev *dev)
 251 {
 252         u8 lat;
 253         pci_read_config_byte(dev, PCI_LATENCY_TIMER, &lat);
 254         if (lat < 16)
 255                 lat = (64 <= pcibios_max_latency) ? 64 : pcibios_max_latency;
 256         else if (lat > pcibios_max_latency)
 257                 lat = pcibios_max_latency;
 258         else
 259                 return;
 260         printk(KERN_DEBUG "PCI: Setting latency timer of device %s to %d\n",
 261                 pci_name(dev), lat);
 262         pci_write_config_byte(dev, PCI_LATENCY_TIMER, lat);
 263 }
 264
 265 static void pci_unmap_page_range(struct vm_area_struct *vma)
 266 {
 267         u64 addr = (u64)vma->vm_pgoff << PAGE_SHIFT;
 268         free_memtype(addr, addr + vma->vm_end - vma->vm_start);
 269 }
 270
 271 static void pci_track_mmap_page_range(struct vm_area_struct *vma)
 272 {
 273         u64 addr = (u64)vma->vm_pgoff << PAGE_SHIFT;
 274         unsigned long flags = pgprot_val(vma->vm_page_prot)
 275                                                 & _PAGE_CACHE_MASK;
 276
 277         reserve_memtype(addr, addr + vma->vm_end - vma->vm_start, flags, NULL);
 278 }
 279
 280 static struct vm_operations_struct pci_mmap_ops = {
 281         .open  = pci_track_mmap_page_range,
 282         .close = pci_unmap_page_range,
 283 };
 284
 285 int pci_mmap_page_range(struct pci_dev *dev, struct vm_area_struct *vma,
 286                         enum pci_mmap_state mmap_state, int write_combine)
 287 {
 288         unsigned long prot;
 289         u64 addr = vma->vm_pgoff << PAGE_SHIFT;
 290         unsigned long len = vma->vm_end - vma->vm_start;
 291         unsigned long flags;
 292         unsigned long new_flags;
 293         int retval;
 294
 295         /* I/O space cannot be accessed via normal processor loads and
 296          * stores on this platform.
 297          */
 298         if (mmap_state == pci_mmap_io)
 299                 return -EINVAL;
 300
 301         prot = pgprot_val(vma->vm_page_prot);
 302         if (pat_enabled && write_combine)
 303                 prot |= _PAGE_CACHE_WC;
 304         else if (pat_enabled || boot_cpu_data.x86 > 3)
 305                 /*
 306                  * ioremap() and ioremap_nocache() defaults to UC MINUS for now.
 307                  * To avoid attribute conflicts, request UC MINUS here
 308                  * aswell.
 309                  */
 310                 prot |= _PAGE_CACHE_UC_MINUS;
 311
 312         vma->vm_page_prot = __pgprot(prot);
 313
 314         flags = pgprot_val(vma->vm_page_prot) & _PAGE_CACHE_MASK;
 315         retval = reserve_memtype(addr, addr + len, flags, &new_flags);
 316         if (retval)
 317                 return retval;
 318
 319         if (flags != new_flags) {
 320                 /*
 321                  * Do not fallback to certain memory types with certain
 322                  * requested type:
 323                  * - request is uncached, return cannot be write-back
 324                  * - request is uncached, return cannot be write-combine
 325                  * - request is write-combine, return cannot be write-back
 326                  */
 327                 if ((flags == _PAGE_CACHE_UC_MINUS &&
 328                      (new_flags == _PAGE_CACHE_WB)) ||
 329                     (flags == _PAGE_CACHE_WC &&
 330                      new_flags == _PAGE_CACHE_WB)) {
 331                         free_memtype(addr, addr+len);
 332                         return -EINVAL;
 333                 }
 334                 flags = new_flags;
 335         }
 336
 337         if (((vma->vm_pgoff < max_low_pfn_mapped) ||
 338              (vma->vm_pgoff >= (1UL<<(32 - PAGE_SHIFT)) &&
 339               vma->vm_pgoff < max_pfn_mapped)) &&
 340             ioremap_change_attr((unsigned long)__va(addr), len, flags)) {
 341                 free_memtype(addr, addr + len);
 342                 return -EINVAL;
 343         }
 344
 345         if (io_remap_pfn_range(vma, vma->vm_start, vma->vm_pgoff,
 346                                vma->vm_end - vma->vm_start,
 347                                vma->vm_page_prot))
 348                 return -EAGAIN;
 349
 350         vma->vm_ops = &pci_mmap_ops;
 351
 352         return 0;
 353 }