arch/x86/pci/direct.c

   1 /*
   2  * direct.c - Low-level direct PCI config space access
   3  */
   4
   5 #include <linux/pci.h>
   6 #include <linux/init.h>
   7 #include <linux/dmi.h>
   8 #include <asm/pci_x86.h>
   9
  10 /*
  11  * Functions for accessing PCI base (first 256 bytes) and extended
  12  * (4096 bytes per PCI function) configuration space with type 1
  13  * accesses.
  14  */
  15
  16 #define PCI_CONF1_ADDRESS(bus, devfn, reg) \
  17         (0x80000000 | ((reg & 0xF00) << 16) | (bus << 16) \
  18         | (devfn << 8) | (reg & 0xFC))
  19
  20 static int pci_conf1_read(unsigned int seg, unsigned int bus,
  21                           unsigned int devfn, int reg, int len, u32 *value)
  22 {
  23         unsigned long flags;
  24
  25         if ((bus > 255) || (devfn > 255) || (reg > 4095)) {
  26                 *value = -1;
  27                 return -EINVAL;
  28         }
  29
  30         spin_lock_irqsave(&pci_config_lock, flags);
  31
  32         outl(PCI_CONF1_ADDRESS(bus, devfn, reg), 0xCF8);
  33
  34         switch (len) {
  35         case 1:
  36                 *value = inb(0xCFC + (reg & 3));
  37                 break;
  38         case 2:
  39                 *value = inw(0xCFC + (reg & 2));
  40                 break;
  41         case 4:
  42                 *value = inl(0xCFC);
  43                 break;
  44         }
  45
  46         spin_unlock_irqrestore(&pci_config_lock, flags);
  47
  48         return 0;
  49 }
  50
  51 static int pci_conf1_write(unsigned int seg, unsigned int bus,
  52                            unsigned int devfn, int reg, int len, u32 value)
  53 {
  54         unsigned long flags;
  55
  56         if ((bus > 255) || (devfn > 255) || (reg > 4095))
  57                 return -EINVAL;
  58
  59         spin_lock_irqsave(&pci_config_lock, flags);
  60
  61         outl(PCI_CONF1_ADDRESS(bus, devfn, reg), 0xCF8);
  62
  63         switch (len) {
  64         case 1:
  65                 outb((u8)value, 0xCFC + (reg & 3));
  66                 break;
  67         case 2:
  68                 outw((u16)value, 0xCFC + (reg & 2));
  69                 break;
  70         case 4:
  71                 outl((u32)value, 0xCFC);
  72                 break;
  73         }
  74
  75         spin_unlock_irqrestore(&pci_config_lock, flags);
  76
  77         return 0;
  78 }
  79
  80 #undef PCI_CONF1_ADDRESS
  81
  82 struct pci_raw_ops pci_direct_conf1 = {
  83         .read =         pci_conf1_read,
  84         .write =        pci_conf1_write,
  85 };
  86
  87
  88 /*
  89  * Functions for accessing PCI configuration space with type 2 accesses
  90  */
  91
  92 #define PCI_CONF2_ADDRESS(dev, reg)     (u16)(0xC000 | (dev << 8) | reg)
  93
  94 static int pci_conf2_read(unsigned int seg, unsigned int bus,
  95                           unsigned int devfn, int reg, int len, u32 *value)
  96 {
  97         unsigned long flags;
  98         int dev, fn;
  99
 100         if ((bus > 255) || (devfn > 255) || (reg > 255)) {
 101                 *value = -1;
 102                 return -EINVAL;
 103         }
 104
 105         dev = PCI_SLOT(devfn);
 106         fn = PCI_FUNC(devfn);
 107
 108         if (dev & 0x10)
 109                 return PCIBIOS_DEVICE_NOT_FOUND;
 110
 111         spin_lock_irqsave(&pci_config_lock, flags);
 112
 113         outb((u8)(0xF0 | (fn << 1)), 0xCF8);
 114         outb((u8)bus, 0xCFA);
 115
 116         switch (len) {
 117         case 1:
 118                 *value = inb(PCI_CONF2_ADDRESS(dev, reg));
 119                 break;
 120         case 2:
 121                 *value = inw(PCI_CONF2_ADDRESS(dev, reg));
 122                 break;
 123         case 4:
 124                 *value = inl(PCI_CONF2_ADDRESS(dev, reg));
 125                 break;
 126         }
 127
 128         outb(0, 0xCF8);
 129
 130         spin_unlock_irqrestore(&pci_config_lock, flags);
 131
 132         return 0;
 133 }
 134
 135 static int pci_conf2_write(unsigned int seg, unsigned int bus,
 136                            unsigned int devfn, int reg, int len, u32 value)
 137 {
 138         unsigned long flags;
 139         int dev, fn;
 140
 141         if ((bus > 255) || (devfn > 255) || (reg > 255))
 142                 return -EINVAL;
 143
 144         dev = PCI_SLOT(devfn);
 145         fn = PCI_FUNC(devfn);
 146
 147         if (dev & 0x10)
 148                 return PCIBIOS_DEVICE_NOT_FOUND;
 149
 150         spin_lock_irqsave(&pci_config_lock, flags);
 151
 152         outb((u8)(0xF0 | (fn << 1)), 0xCF8);
 153         outb((u8)bus, 0xCFA);
 154
 155         switch (len) {
 156         case 1:
 157                 outb((u8)value, PCI_CONF2_ADDRESS(dev, reg));
 158                 break;
 159         case 2:
 160                 outw((u16)value, PCI_CONF2_ADDRESS(dev, reg));
 161                 break;
 162         case 4:
 163                 outl((u32)value, PCI_CONF2_ADDRESS(dev, reg));
 164                 break;
 165         }
 166
 167         outb(0, 0xCF8);
 168
 169         spin_unlock_irqrestore(&pci_config_lock, flags);
 170
 171         return 0;
 172 }
 173
 174 #undef PCI_CONF2_ADDRESS
 175
 176 struct pci_raw_ops pci_direct_conf2 = {
 177         .read =         pci_conf2_read,
 178         .write =        pci_conf2_write,
 179 };
 180
 181
 182 /*
 183  * Before we decide to use direct hardware access mechanisms, we try to do some
 184  * trivial checks to ensure it at least _seems_ to be working -- we just test
 185  * whether bus 00 contains a host bridge (this is similar to checking
 186  * techniques used in XFree86, but ours should be more reliable since we
 187  * attempt to make use of direct access hints provided by the PCI BIOS).
 188  *
 189  * This should be close to trivial, but it isn't, because there are buggy
 190  * chipsets (yes, you guessed it, by Intel and Compaq) that have no class ID.
 191  */
 192 static int __init pci_sanity_check(struct pci_raw_ops *o)
 193 {
 194         u32 x = 0;
 195         int devfn;
 196
 197         if (pci_probe & PCI_NO_CHECKS)
 198                 return 1;
 199         /* Assume Type 1 works for newer systems.
 200            This handles machines that don't have anything on PCI Bus 0. */
 201         if (dmi_get_year(DMI_BIOS_DATE) >= 2001)
 202                 return 1;
 203
 204         for (devfn = 0; devfn < 0x100; devfn++) {
 205                 if (o->read(0, 0, devfn, PCI_CLASS_DEVICE, 2, &x))
 206                         continue;
 207                 if (x == PCI_CLASS_BRIDGE_HOST || x == PCI_CLASS_DISPLAY_VGA)
 208                         return 1;
 209
 210                 if (o->read(0, 0, devfn, PCI_VENDOR_ID, 2, &x))
 211                         continue;
 212                 if (x == PCI_VENDOR_ID_INTEL || x == PCI_VENDOR_ID_COMPAQ)
 213                         return 1;
 214         }
 215
 216         DBG(KERN_WARNING "PCI: Sanity check failed\n");
 217         return 0;
 218 }
 219
 220 static int __init pci_check_type1(void)
 221 {
 222         unsigned long flags;
 223         unsigned int tmp;
 224         int works = 0;
 225
 226         local_irq_save(flags);
 227
 228         outb(0x01, 0xCFB);
 229         tmp = inl(0xCF8);
 230         outl(0x80000000, 0xCF8);
 231         if (inl(0xCF8) == 0x80000000 && pci_sanity_check(&pci_direct_conf1)) {
 232                 works = 1;
 233         }
 234         outl(tmp, 0xCF8);
 235         local_irq_restore(flags);
 236
 237         return works;
 238 }
 239
 240 static int __init pci_check_type2(void)
 241 {
 242         unsigned long flags;
 243         int works = 0;
 244
 245         local_irq_save(flags);
 246
 247         outb(0x00, 0xCFB);
 248         outb(0x00, 0xCF8);
 249         outb(0x00, 0xCFA);
 250         if (inb(0xCF8) == 0x00 && inb(0xCFA) == 0x00 &&
 251             pci_sanity_check(&pci_direct_conf2)) {
 252                 works = 1;
 253         }
 254
 255         local_irq_restore(flags);
 256
 257         return works;
 258 }
 259
 260 void __init pci_direct_init(int type)
 261 {
 262         if (type == 0)
 263                 return;
 264         printk(KERN_INFO "PCI: Using configuration type %d for base access\n",
 265                  type);
 266         if (type == 1) {
 267                 raw_pci_ops = &pci_direct_conf1;
 268                 if (raw_pci_ext_ops)
 269                         return;
 270                 if (!(pci_probe & PCI_HAS_IO_ECS))
 271                         return;
 272                 printk(KERN_INFO "PCI: Using configuration type 1 "
 273                        "for extended access\n");
 274                 raw_pci_ext_ops = &pci_direct_conf1;
 275                 return;
 276         }
 277         raw_pci_ops = &pci_direct_conf2;
 278 }
 279
 280 int __init pci_direct_probe(void)
 281 {
 282         struct resource *region, *region2;
 283
 284         if ((pci_probe & PCI_PROBE_CONF1) == 0)
 285                 goto type2;
 286         region = request_region(0xCF8, 8, "PCI conf1");
 287         if (!region)
 288                 goto type2;
 289
 290         if (pci_check_type1()) {
 291                 raw_pci_ops = &pci_direct_conf1;
 292                 port_cf9_safe = true;
 293                 return 1;
 294         }
 295         release_resource(region);
 296
 297  type2:
 298         if ((pci_probe & PCI_PROBE_CONF2) == 0)
 299                 return 0;
 300         region = request_region(0xCF8, 4, "PCI conf2");
 301         if (!region)
 302                 return 0;
 303         region2 = request_region(0xC000, 0x1000, "PCI conf2");
 304         if (!region2)
 305                 goto fail2;
 306
 307         if (pci_check_type2()) {
 308                 raw_pci_ops = &pci_direct_conf2;
 309                 port_cf9_safe = true;
 310                 return 2;
 311         }
 312
 313         release_resource(region2);
 314  fail2:
 315         release_resource(region);
 316         return 0;
 317 }