arch/x86/kernel/aperture_64.c

   1 /*
   2  * Firmware replacement code.
   3  *
   4  * Work around broken BIOSes that don't set an aperture or only set the
   5  * aperture in the AGP bridge.
   6  * If all fails map the aperture over some low memory.  This is cheaper than
   7  * doing bounce buffering. The memory is lost. This is done at early boot
   8  * because only the bootmem allocator can allocate 32+MB.
   9  *
  10  * Copyright 2002 Andi Kleen, SuSE Labs.
  11  */
  12 #include <linux/kernel.h>
  13 #include <linux/types.h>
  14 #include <linux/init.h>
  15 #include <linux/bootmem.h>
  16 #include <linux/mmzone.h>
  17 #include <linux/pci_ids.h>
  18 #include <linux/pci.h>
  19 #include <linux/bitops.h>
  20 #include <linux/ioport.h>
  21 #include <asm/e820.h>
  22 #include <asm/io.h>
  23 #include <asm/gart.h>
  24 #include <asm/pci-direct.h>
  25 #include <asm/dma.h>
  26 #include <asm/k8.h>
  27
  28 int gart_iommu_aperture;
  29 int gart_iommu_aperture_disabled __initdata = 0;
  30 int gart_iommu_aperture_allowed __initdata = 0;
  31
  32 int fallback_aper_order __initdata = 1; /* 64MB */
  33 int fallback_aper_force __initdata = 0;
  34
  35 int fix_aperture __initdata = 1;
  36
  37 static struct resource gart_resource = {
  38         .name   = "GART",
  39         .flags  = IORESOURCE_MEM,
  40 };
  41
  42 static void __init insert_aperture_resource(u32 aper_base, u32 aper_size)
  43 {
  44         gart_resource.start = aper_base;
  45         gart_resource.end = aper_base + aper_size - 1;
  46         insert_resource(&iomem_resource, &gart_resource);
  47 }
  48
  49 /* This code runs before the PCI subsystem is initialized, so just
  50    access the northbridge directly. */
  51
  52 static u32 __init allocate_aperture(void)
  53 {
  54         u32 aper_size;
  55         void *p;
  56
  57         if (fallback_aper_order > 7)
  58                 fallback_aper_order = 7;
  59         aper_size = (32 * 1024 * 1024) << fallback_aper_order;
  60
  61         /*
  62          * Aperture has to be naturally aligned. This means a 2GB aperture
  63          * won't have much chance of finding a place in the lower 4GB of
  64          * memory. Unfortunately we cannot move it up because that would
  65          * make the IOMMU useless.
  66          */
  67         p = __alloc_bootmem_nopanic(aper_size, aper_size, 0);
  68         if (!p || __pa(p)+aper_size > 0xffffffff) {
  69                 printk(KERN_ERR
  70                         "Cannot allocate aperture memory hole (%p,%uK)\n",
  71                                 p, aper_size>>10);
  72                 if (p)
  73                         free_bootmem(__pa(p), aper_size);
  74                 return 0;
  75         }
  76         printk(KERN_INFO "Mapping aperture over %d KB of RAM @ %lx\n",
  77                         aper_size >> 10, __pa(p));
  78         insert_aperture_resource((u32)__pa(p), aper_size);
  79
  80         return (u32)__pa(p);
  81 }
  82
  83 static int __init aperture_valid(u64 aper_base, u32 aper_size)
  84 {
  85         if (!aper_base)
  86                 return 0;
  87
  88         if (aper_size < 64*1024*1024) {
  89                 printk(KERN_ERR "Aperture too small (%d MB)\n", aper_size>>20);
  90                 return 0;
  91         }
  92         if (aper_base + aper_size > 0x100000000UL) {
  93                 printk(KERN_ERR "Aperture beyond 4GB. Ignoring.\n");
  94                 return 0;
  95         }
  96         if (e820_any_mapped(aper_base, aper_base + aper_size, E820_RAM)) {
  97                 printk(KERN_ERR "Aperture pointing to e820 RAM. Ignoring.\n");
  98                 return 0;
  99         }
 100
 101         return 1;
 102 }
 103
 104 /* Find a PCI capability */
 105 static __u32 __init find_cap(int num, int slot, int func, int cap)
 106 {
 107         int bytes;
 108         u8 pos;
 109
 110         if (!(read_pci_config_16(num, slot, func, PCI_STATUS) &
 111                                                 PCI_STATUS_CAP_LIST))
 112                 return 0;
 113
 114         pos = read_pci_config_byte(num, slot, func, PCI_CAPABILITY_LIST);
 115         for (bytes = 0; bytes < 48 && pos >= 0x40; bytes++) {
 116                 u8 id;
 117
 118                 pos &= ~3;
 119                 id = read_pci_config_byte(num, slot, func, pos+PCI_CAP_LIST_ID);
 120                 if (id == 0xff)
 121                         break;
 122                 if (id == cap)
 123                         return pos;
 124                 pos = read_pci_config_byte(num, slot, func,
 125                                                 pos+PCI_CAP_LIST_NEXT);
 126         }
 127         return 0;
 128 }
 129
 130 /* Read a standard AGPv3 bridge header */
 131 static __u32 __init read_agp(int num, int slot, int func, int cap, u32 *order)
 132 {
 133         u32 apsize;
 134         u32 apsizereg;
 135         int nbits;
 136         u32 aper_low, aper_hi;
 137         u64 aper;
 138
 139         printk(KERN_INFO "AGP bridge at %02x:%02x:%02x\n", num, slot, func);
 140         apsizereg = read_pci_config_16(num, slot, func, cap + 0x14);
 141         if (apsizereg == 0xffffffff) {
 142                 printk(KERN_ERR "APSIZE in AGP bridge unreadable\n");
 143                 return 0;
 144         }
 145
 146         apsize = apsizereg & 0xfff;
 147         /* Some BIOS use weird encodings not in the AGPv3 table. */
 148         if (apsize & 0xff)
 149                 apsize |= 0xf00;
 150         nbits = hweight16(apsize);
 151         *order = 7 - nbits;
 152         if ((int)*order < 0) /* < 32MB */
 153                 *order = 0;
 154
 155         aper_low = read_pci_config(num, slot, func, 0x10);
 156         aper_hi = read_pci_config(num, slot, func, 0x14);
 157         aper = (aper_low & ~((1<<22)-1)) | ((u64)aper_hi << 32);
 158
 159         printk(KERN_INFO "Aperture from AGP @ %Lx size %u MB (APSIZE %x)\n",
 160                         aper, 32 << *order, apsizereg);
 161
 162         if (!aperture_valid(aper, (32*1024*1024) << *order))
 163                 return 0;
 164         return (u32)aper;
 165 }
 166
 167 /*
 168  * Look for an AGP bridge. Windows only expects the aperture in the
 169  * AGP bridge and some BIOS forget to initialize the Northbridge too.
 170  * Work around this here.
 171  *
 172  * Do an PCI bus scan by hand because we're running before the PCI
 173  * subsystem.
 174  *
 175  * All K8 AGP bridges are AGPv3 compliant, so we can do this scan
 176  * generically. It's probably overkill to always scan all slots because
 177  * the AGP bridges should be always an own bus on the HT hierarchy,
 178  * but do it here for future safety.
 179  */
 180 static __u32 __init search_agp_bridge(u32 *order, int *valid_agp)
 181 {
 182         int num, slot, func;
 183
 184         /* Poor man's PCI discovery */
 185         for (num = 0; num < 256; num++) {
 186                 for (slot = 0; slot < 32; slot++) {
 187                         for (func = 0; func < 8; func++) {
 188                                 u32 class, cap;
 189                                 u8 type;
 190                                 class = read_pci_config(num, slot, func,
 191                                                         PCI_CLASS_REVISION);
 192                                 if (class == 0xffffffff)
 193                                         break;
 194
 195                                 switch (class >> 16) {
 196                                 case PCI_CLASS_BRIDGE_HOST:
 197                                 case PCI_CLASS_BRIDGE_OTHER: /* needed? */
 198                                         /* AGP bridge? */
 199                                         cap = find_cap(num, slot, func,
 200                                                         PCI_CAP_ID_AGP);
 201                                         if (!cap)
 202                                                 break;
 203                                         *valid_agp = 1;
 204                                         return read_agp(num, slot, func, cap,
 205                                                         order);
 206                                 }
 207
 208                                 /* No multi-function device? */
 209                                 type = read_pci_config_byte(num, slot, func,
 210                                                                PCI_HEADER_TYPE);
 211                                 if (!(type & 0x80))
 212                                         break;
 213                         }
 214                 }
 215         }
 216         printk(KERN_INFO "No AGP bridge found\n");
 217
 218         return 0;
 219 }
 220
 221 void __init gart_iommu_hole_init(void)
 222 {
 223         u32 aper_size, aper_alloc = 0, aper_order = 0, last_aper_order = 0;
 224         u64 aper_base, last_aper_base = 0;
 225         int fix, num, valid_agp = 0;
 226
 227         if (gart_iommu_aperture_disabled || !fix_aperture ||
 228             !early_pci_allowed())
 229                 return;
 230
 231         printk(KERN_INFO  "Checking aperture...\n");
 232
 233         fix = 0;
 234         for (num = 24; num < 32; num++) {
 235                 if (!early_is_k8_nb(read_pci_config(0, num, 3, 0x00)))
 236                         continue;
 237
 238                 iommu_detected = 1;
 239                 gart_iommu_aperture = 1;
 240
 241                 aper_order = (read_pci_config(0, num, 3, 0x90) >> 1) & 7;
 242                 aper_size = (32 * 1024 * 1024) << aper_order;
 243                 aper_base = read_pci_config(0, num, 3, 0x94) & 0x7fff;
 244                 aper_base <<= 25;
 245
 246                 printk(KERN_INFO "CPU %d: aperture @ %Lx size %u MB\n",
 247                                 num-24, aper_base, aper_size>>20);
 248
 249                 if (!aperture_valid(aper_base, aper_size)) {
 250                         fix = 1;
 251                         break;
 252                 }
 253
 254                 if ((last_aper_order && aper_order != last_aper_order) ||
 255                     (last_aper_base && aper_base != last_aper_base)) {
 256                         fix = 1;
 257                         break;
 258                 }
 259                 last_aper_order = aper_order;
 260                 last_aper_base = aper_base;
 261         }
 262
 263         if (!fix && !fallback_aper_force) {
 264                 if (last_aper_base) {
 265                         unsigned long n = (32 * 1024 * 1024) << last_aper_order;
 266
 267                         insert_aperture_resource((u32)last_aper_base, n);
 268                 }
 269                 return;
 270         }
 271
 272         if (!fallback_aper_force)
 273                 aper_alloc = search_agp_bridge(&aper_order, &valid_agp);
 274
 275         if (aper_alloc) {
 276                 /* Got the aperture from the AGP bridge */
 277         } else if (swiotlb && !valid_agp) {
 278                 /* Do nothing */
 279         } else if ((!no_iommu && end_pfn > MAX_DMA32_PFN) ||
 280                    force_iommu ||
 281                    valid_agp ||
 282                    fallback_aper_force) {
 283                 printk(KERN_ERR
 284                         "Your BIOS doesn't leave a aperture memory hole\n");
 285                 printk(KERN_ERR
 286                         "Please enable the IOMMU option in the BIOS setup\n");
 287                 printk(KERN_ERR
 288                         "This costs you %d MB of RAM\n",
 289                                 32 << fallback_aper_order);
 290
 291                 aper_order = fallback_aper_order;
 292                 aper_alloc = allocate_aperture();
 293                 if (!aper_alloc) {
 294                         /*
 295                          * Could disable AGP and IOMMU here, but it's
 296                          * probably not worth it. But the later users
 297                          * cannot deal with bad apertures and turning
 298                          * on the aperture over memory causes very
 299                          * strange problems, so it's better to panic
 300                          * early.
 301                          */
 302                         panic("Not enough memory for aperture");
 303                 }
 304         } else {
 305                 return;
 306         }
 307
 308         /* Fix up the north bridges */
 309         for (num = 24; num < 32; num++) {
 310                 if (!early_is_k8_nb(read_pci_config(0, num, 3, 0x00)))
 311                         continue;
 312
 313                 /*
 314                  * Don't enable translation yet. That is done later.
 315                  * Assume this BIOS didn't initialise the GART so
 316                  * just overwrite all previous bits
 317                  */
 318                 write_pci_config(0, num, 3, 0x90, aper_order<<1);
 319                 write_pci_config(0, num, 3, 0x94, aper_alloc>>25);
 320         }
 321 }