LXR linux/arch/x86/pci/pcbios.c

   1/*
   2 * BIOS32 and PCI BIOS handling.
   3 */
   4
   5#include <linux/pci.h>
   6#include <linux/init.h>
   7#include <linux/slab.h>
   8#include <linux/module.h>
   9#include <linux/uaccess.h>
  10#include <asm/pci_x86.h>
  11#include <asm/pci-functions.h>
  12#include <asm/cacheflush.h>
  13
  14/* BIOS32 signature: "_32_" */
  15#define BIOS32_SIGNATURE        (('_' << 0) + ('3' << 8) + ('2' << 16) + ('_' << 24))
  16
  17/* PCI signature: "PCI " */
  18#define PCI_SIGNATURE           (('P' << 0) + ('C' << 8) + ('I' << 16) + (' ' << 24))
  19
  20/* PCI service signature: "$PCI" */
  21#define PCI_SERVICE             (('$' << 0) + ('P' << 8) + ('C' << 16) + ('I' << 24))
  22
  23/* PCI BIOS hardware mechanism flags */
  24#define PCIBIOS_HW_TYPE1                0x01
  25#define PCIBIOS_HW_TYPE2                0x02
  26#define PCIBIOS_HW_TYPE1_SPEC           0x10
  27#define PCIBIOS_HW_TYPE2_SPEC           0x20
  28
  29int pcibios_enabled;
  30
  31/* According to the BIOS specification at:
  32 * http://members.datafast.net.au/dft0802/specs/bios21.pdf, we could
  33 * restrict the x zone to some pages and make it ro. But this may be
  34 * broken on some bios, complex to handle with static_protections.
  35 * We could make the 0xe0000-0x100000 range rox, but this can break
  36 * some ISA mapping.
  37 *
  38 * So we let's an rw and x hole when pcibios is used. This shouldn't
  39 * happen for modern system with mmconfig, and if you don't want it
  40 * you could disable pcibios...
  41 */
  42static inline void set_bios_x(void)
  43{
  44        pcibios_enabled = 1;
  45        set_memory_x(PAGE_OFFSET + BIOS_BEGIN, (BIOS_END - BIOS_BEGIN) >> PAGE_SHIFT);
  46        if (__supported_pte_mask & _PAGE_NX)
  47                printk(KERN_INFO "PCI : PCI BIOS area is rw and x. Use pci=nobios if you want it NX.\n");
  48}
  49
  50/*
  51 * This is the standard structure used to identify the entry point
  52 * to the BIOS32 Service Directory, as documented in
  53 *      Standard BIOS 32-bit Service Directory Proposal
  54 *      Revision 0.4 May 24, 1993
  55 *      Phoenix Technologies Ltd.
  56 *      Norwood, MA
  57 * and the PCI BIOS specification.
  58 */
  59
  60union bios32 {
  61        struct {
  62                unsigned long signature;        /* _32_ */
  63                unsigned long entry;            /* 32 bit physical address */
  64                unsigned char revision;         /* Revision level, 0 */
  65                unsigned char length;           /* Length in paragraphs should be 01 */
  66                unsigned char checksum;         /* All bytes must add up to zero */
  67                unsigned char reserved[5];      /* Must be zero */
  68        } fields;
  69        char chars[16];
  70};
  71
  72/*
  73 * Physical address of the service directory.  I don't know if we're
  74 * allowed to have more than one of these or not, so just in case
  75 * we'll make pcibios_present() take a memory start parameter and store
  76 * the array there.
  77 */
  78
  79static struct {
  80        unsigned long address;
  81        unsigned short segment;
  82} bios32_indirect __initdata = { 0, __KERNEL_CS };
  83
  84/*
  85 * Returns the entry point for the given service, NULL on error
  86 */
  87
  88static unsigned long __init bios32_service(unsigned long service)
  89{
  90        unsigned char return_code;      /* %al */
  91        unsigned long address;          /* %ebx */
  92        unsigned long length;           /* %ecx */
  93        unsigned long entry;            /* %edx */
  94        unsigned long flags;
  95
  96        local_irq_save(flags);
  97        __asm__("lcall *(%%edi); cld"
  98                : "=a" (return_code),
  99                  "=b" (address),
 100                  "=c" (length),
 101                  "=d" (entry)
 102                : "0" (service),
 103                  "1" (0),
 104                  "D" (&bios32_indirect));
 105        local_irq_restore(flags);
 106
 107        switch (return_code) {
 108                case 0:
 109                        return address + entry;
 110                case 0x80:      /* Not present */
 111                        printk(KERN_WARNING "bios32_service(0x%lx): not present\n", service);
 112                        return 0;
 113                default: /* Shouldn't happen */
 114                        printk(KERN_WARNING "bios32_service(0x%lx): returned 0x%x -- BIOS bug!\n",
 115                                service, return_code);
 116                        return 0;
 117        }
 118}
 119
 120static struct {
 121        unsigned long address;
 122        unsigned short segment;
 123} pci_indirect = { 0, __KERNEL_CS };
 124
 125static int pci_bios_present;
 126
 127static int __init check_pcibios(void)
 128{
 129        u32 signature, eax, ebx, ecx;
 130        u8 status, major_ver, minor_ver, hw_mech;
 131        unsigned long flags, pcibios_entry;
 132
 133        if ((pcibios_entry = bios32_service(PCI_SERVICE))) {
 134                pci_indirect.address = pcibios_entry + PAGE_OFFSET;
 135
 136                local_irq_save(flags);
 137                __asm__(
 138                        "lcall *(%%edi); cld\n\t"
 139                        "jc 1f\n\t"
 140                        "xor %%ah, %%ah\n"
 141                        "1:"
 142                        : "=d" (signature),
 143                          "=a" (eax),
 144                          "=b" (ebx),
 145                          "=c" (ecx)
 146                        : "1" (PCIBIOS_PCI_BIOS_PRESENT),
 147                          "D" (&pci_indirect)
 148                        : "memory");
 149                local_irq_restore(flags);
 150
 151                status = (eax >> 8) & 0xff;
 152                hw_mech = eax & 0xff;
 153                major_ver = (ebx >> 8) & 0xff;
 154                minor_ver = ebx & 0xff;
 155                if (pcibios_last_bus < 0)
 156                        pcibios_last_bus = ecx & 0xff;
 157                DBG("PCI: BIOS probe returned s=%02x hw=%02x ver=%02x.%02x l=%02x\n",
 158                        status, hw_mech, major_ver, minor_ver, pcibios_last_bus);
 159                if (status || signature != PCI_SIGNATURE) {
 160                        printk (KERN_ERR "PCI: BIOS BUG #%x[%08x] found\n",
 161                                status, signature);
 162                        return 0;
 163                }
 164                printk(KERN_INFO "PCI: PCI BIOS revision %x.%02x entry at 0x%lx, last bus=%d\n",
 165                        major_ver, minor_ver, pcibios_entry, pcibios_last_bus);
 166#ifdef CONFIG_PCI_DIRECT
 167                if (!(hw_mech & PCIBIOS_HW_TYPE1))
 168                        pci_probe &= ~PCI_PROBE_CONF1;
 169                if (!(hw_mech & PCIBIOS_HW_TYPE2))
 170                        pci_probe &= ~PCI_PROBE_CONF2;
 171#endif
 172                return 1;
 173        }
 174        return 0;
 175}
 176
 177static int pci_bios_read(unsigned int seg, unsigned int bus,
 178                         unsigned int devfn, int reg, int len, u32 *value)
 179{
 180        unsigned long result = 0;
 181        unsigned long flags;
 182        unsigned long bx = (bus << 8) | devfn;
 183        u16 number = 0, mask = 0;
 184
 185        WARN_ON(seg);
 186        if (!value || (bus > 255) || (devfn > 255) || (reg > 255))
 187                return -EINVAL;
 188
 189        raw_spin_lock_irqsave(&pci_config_lock, flags);
 190
 191        switch (len) {
 192        case 1:
 193                number = PCIBIOS_READ_CONFIG_BYTE;
 194                mask = 0xff;
 195                break;
 196        case 2:
 197                number = PCIBIOS_READ_CONFIG_WORD;
 198                mask = 0xffff;
 199                break;
 200        case 4:
 201                number = PCIBIOS_READ_CONFIG_DWORD;
 202                break;
 203        }
 204
 205        __asm__("lcall *(%%esi); cld\n\t"
 206                "jc 1f\n\t"
 207                "xor %%ah, %%ah\n"
 208                "1:"
 209                : "=c" (*value),
 210                  "=a" (result)
 211                : "1" (number),
 212                  "b" (bx),
 213                  "D" ((long)reg),
 214                  "S" (&pci_indirect));
 215        /*
 216         * Zero-extend the result beyond 8 or 16 bits, do not trust the
 217         * BIOS having done it:
 218         */
 219        if (mask)
 220                *value &= mask;
 221
 222        raw_spin_unlock_irqrestore(&pci_config_lock, flags);
 223
 224        return (int)((result & 0xff00) >> 8);
 225}
 226
 227static int pci_bios_write(unsigned int seg, unsigned int bus,
 228                          unsigned int devfn, int reg, int len, u32 value)
 229{
 230        unsigned long result = 0;
 231        unsigned long flags;
 232        unsigned long bx = (bus << 8) | devfn;
 233        u16 number = 0;
 234
 235        WARN_ON(seg);
 236        if ((bus > 255) || (devfn > 255) || (reg > 255)) 
 237                return -EINVAL;
 238
 239        raw_spin_lock_irqsave(&pci_config_lock, flags);
 240
 241        switch (len) {
 242        case 1:
 243                number = PCIBIOS_WRITE_CONFIG_BYTE;
 244                break;
 245        case 2:
 246                number = PCIBIOS_WRITE_CONFIG_WORD;
 247                break;
 248        case 4:
 249                number = PCIBIOS_WRITE_CONFIG_DWORD;
 250                break;
 251        }
 252
 253        __asm__("lcall *(%%esi); cld\n\t"
 254                "jc 1f\n\t"
 255                "xor %%ah, %%ah\n"
 256                "1:"
 257                : "=a" (result)
 258                : "0" (number),
 259                  "c" (value),
 260                  "b" (bx),
 261                  "D" ((long)reg),
 262                  "S" (&pci_indirect));
 263
 264        raw_spin_unlock_irqrestore(&pci_config_lock, flags);
 265
 266        return (int)((result & 0xff00) >> 8);
 267}
 268
 269
 270/*
 271 * Function table for BIOS32 access
 272 */
 273
 274static const struct pci_raw_ops pci_bios_access = {
 275        .read =         pci_bios_read,
 276        .write =        pci_bios_write
 277};
 278
 279/*
 280 * Try to find PCI BIOS.
 281 */
 282
 283static const struct pci_raw_ops *__init pci_find_bios(void)
 284{
 285        union bios32 *check;
 286        unsigned char sum;
 287        int i, length;
 288
 289        /*
 290         * Follow the standard procedure for locating the BIOS32 Service
 291         * directory by scanning the permissible address range from
 292         * 0xe0000 through 0xfffff for a valid BIOS32 structure.
 293         */
 294
 295        for (check = (union bios32 *) __va(0xe0000);
 296             check <= (union bios32 *) __va(0xffff0);
 297             ++check) {
 298                long sig;
 299                if (probe_kernel_address(&check->fields.signature, sig))
 300                        continue;
 301
 302                if (check->fields.signature != BIOS32_SIGNATURE)
 303                        continue;
 304                length = check->fields.length * 16;
 305                if (!length)
 306                        continue;
 307                sum = 0;
 308                for (i = 0; i < length ; ++i)
 309                        sum += check->chars[i];
 310                if (sum != 0)
 311                        continue;
 312                if (check->fields.revision != 0) {
 313                        printk("PCI: unsupported BIOS32 revision %d at 0x%p\n",
 314                                check->fields.revision, check);
 315                        continue;
 316                }
 317                DBG("PCI: BIOS32 Service Directory structure at 0x%p\n", check);
 318                if (check->fields.entry >= 0x100000) {
 319                        printk("PCI: BIOS32 entry (0x%p) in high memory, "
 320                                        "cannot use.\n", check);
 321                        return NULL;
 322                } else {
 323                        unsigned long bios32_entry = check->fields.entry;
 324                        DBG("PCI: BIOS32 Service Directory entry at 0x%lx\n",
 325                                        bios32_entry);
 326                        bios32_indirect.address = bios32_entry + PAGE_OFFSET;
 327                        set_bios_x();
 328                        if (check_pcibios())
 329                                return &pci_bios_access;
 330                }
 331                break;  /* Hopefully more than one BIOS32 cannot happen... */
 332        }
 333
 334        return NULL;
 335}
 336
 337/*
 338 *  BIOS Functions for IRQ Routing
 339 */
 340
 341struct irq_routing_options {
 342        u16 size;
 343        struct irq_info *table;
 344        u16 segment;
 345} __attribute__((packed));
 346
 347struct irq_routing_table * pcibios_get_irq_routing_table(void)
 348{
 349        struct irq_routing_options opt;
 350        struct irq_routing_table *rt = NULL;
 351        int ret, map;
 352        unsigned long page;
 353
 354        if (!pci_bios_present)
 355                return NULL;
 356        page = __get_free_page(GFP_KERNEL);
 357        if (!page)
 358                return NULL;
 359        opt.table = (struct irq_info *) page;
 360        opt.size = PAGE_SIZE;
 361        opt.segment = __KERNEL_DS;
 362
 363        DBG("PCI: Fetching IRQ routing table... ");
 364        __asm__("push %%es\n\t"
 365                "push %%ds\n\t"
 366                "pop  %%es\n\t"
 367                "lcall *(%%esi); cld\n\t"
 368                "pop %%es\n\t"
 369                "jc 1f\n\t"
 370                "xor %%ah, %%ah\n"
 371                "1:"
 372                : "=a" (ret),
 373                  "=b" (map),
 374                  "=m" (opt)
 375                : "0" (PCIBIOS_GET_ROUTING_OPTIONS),
 376                  "1" (0),
 377                  "D" ((long) &opt),
 378                  "S" (&pci_indirect),
 379                  "m" (opt)
 380                : "memory");
 381        DBG("OK  ret=%d, size=%d, map=%x\n", ret, opt.size, map);
 382        if (ret & 0xff00)
 383                printk(KERN_ERR "PCI: Error %02x when fetching IRQ routing table.\n", (ret >> 8) & 0xff);
 384        else if (opt.size) {
 385                rt = kmalloc(sizeof(struct irq_routing_table) + opt.size, GFP_KERNEL);
 386                if (rt) {
 387                        memset(rt, 0, sizeof(struct irq_routing_table));
 388                        rt->size = opt.size + sizeof(struct irq_routing_table);
 389                        rt->exclusive_irqs = map;
 390                        memcpy(rt->slots, (void *) page, opt.size);
 391                        printk(KERN_INFO "PCI: Using BIOS Interrupt Routing Table\n");
 392                }
 393        }
 394        free_page(page);
 395        return rt;
 396}
 397EXPORT_SYMBOL(pcibios_get_irq_routing_table);
 398
 399int pcibios_set_irq_routing(struct pci_dev *dev, int pin, int irq)
 400{
 401        int ret;
 402
 403        __asm__("lcall *(%%esi); cld\n\t"
 404                "jc 1f\n\t"
 405                "xor %%ah, %%ah\n"
 406                "1:"
 407                : "=a" (ret)
 408                : "0" (PCIBIOS_SET_PCI_HW_INT),
 409                  "b" ((dev->bus->number << 8) | dev->devfn),
 410                  "c" ((irq << 8) | (pin + 10)),
 411                  "S" (&pci_indirect));
 412        return !(ret & 0xff00);
 413}
 414EXPORT_SYMBOL(pcibios_set_irq_routing);
 415
 416void __init pci_pcbios_init(void)
 417{
 418        if ((pci_probe & PCI_PROBE_BIOS) 
 419                && ((raw_pci_ops = pci_find_bios()))) {
 420                pci_bios_present = 1;
 421        }
 422}
 423
 424