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pcbios.c

/*
 * BIOS32 and PCI BIOS handling.
 */

#include <linux/pci.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/uaccess.h>
#include "pci.h"
#include "pci-functions.h"


/* BIOS32 signature: "_32_" */
#define BIOS32_SIGNATURE      (('_' << 0) + ('3' << 8) + ('2' << 16) + ('_' << 24))

/* PCI signature: "PCI " */
#define PCI_SIGNATURE         (('P' << 0) + ('C' << 8) + ('I' << 16) + (' ' << 24))

/* PCI service signature: "$PCI" */
#define PCI_SERVICE           (('$' << 0) + ('P' << 8) + ('C' << 16) + ('I' << 24))

/* PCI BIOS hardware mechanism flags */
#define PCIBIOS_HW_TYPE1            0x01
#define PCIBIOS_HW_TYPE2            0x02
#define PCIBIOS_HW_TYPE1_SPEC       0x10
#define PCIBIOS_HW_TYPE2_SPEC       0x20

/*
 * This is the standard structure used to identify the entry point
 * to the BIOS32 Service Directory, as documented in
 *    Standard BIOS 32-bit Service Directory Proposal
 *    Revision 0.4 May 24, 1993
 *    Phoenix Technologies Ltd.
 *    Norwood, MA
 * and the PCI BIOS specification.
 */

union bios32 {
      struct {
            unsigned long signature;      /* _32_ */
            unsigned long entry;          /* 32 bit physical address */
            unsigned char revision;       /* Revision level, 0 */
            unsigned char length;         /* Length in paragraphs should be 01 */
            unsigned char checksum;       /* All bytes must add up to zero */
            unsigned char reserved[5];    /* Must be zero */
      } fields;
      char chars[16];
};

/*
 * Physical address of the service directory.  I don't know if we're
 * allowed to have more than one of these or not, so just in case
 * we'll make pcibios_present() take a memory start parameter and store
 * the array there.
 */

static struct {
      unsigned long address;
      unsigned short segment;
} bios32_indirect = { 0, __KERNEL_CS };

/*
 * Returns the entry point for the given service, NULL on error
 */

static unsigned long bios32_service(unsigned long service)
{
      unsigned char return_code;    /* %al */
      unsigned long address;        /* %ebx */
      unsigned long length;         /* %ecx */
      unsigned long entry;          /* %edx */
      unsigned long flags;

      local_irq_save(flags);
      __asm__("lcall *(%%edi); cld"
            : "=a" (return_code),
              "=b" (address),
              "=c" (length),
              "=d" (entry)
            : "0" (service),
              "1" (0),
              "D" (&bios32_indirect));
      local_irq_restore(flags);

      switch (return_code) {
            case 0:
                  return address + entry;
            case 0x80:  /* Not present */
                  printk(KERN_WARNING "bios32_service(0x%lx): not present\n", service);
                  return 0;
            default: /* Shouldn't happen */
                  printk(KERN_WARNING "bios32_service(0x%lx): returned 0x%x -- BIOS bug!\n",
                        service, return_code);
                  return 0;
      }
}

static struct {
      unsigned long address;
      unsigned short segment;
} pci_indirect = { 0, __KERNEL_CS };

static int pci_bios_present;

static int __devinit check_pcibios(void)
{
      u32 signature, eax, ebx, ecx;
      u8 status, major_ver, minor_ver, hw_mech;
      unsigned long flags, pcibios_entry;

      if ((pcibios_entry = bios32_service(PCI_SERVICE))) {
            pci_indirect.address = pcibios_entry + PAGE_OFFSET;

            local_irq_save(flags);
            __asm__(
                  "lcall *(%%edi); cld\n\t"
                  "jc 1f\n\t"
                  "xor %%ah, %%ah\n"
                  "1:"
                  : "=d" (signature),
                    "=a" (eax),
                    "=b" (ebx),
                    "=c" (ecx)
                  : "1" (PCIBIOS_PCI_BIOS_PRESENT),
                    "D" (&pci_indirect)
                  : "memory");
            local_irq_restore(flags);

            status = (eax >> 8) & 0xff;
            hw_mech = eax & 0xff;
            major_ver = (ebx >> 8) & 0xff;
            minor_ver = ebx & 0xff;
            if (pcibios_last_bus < 0)
                  pcibios_last_bus = ecx & 0xff;
            DBG("PCI: BIOS probe returned s=%02x hw=%02x ver=%02x.%02x l=%02x\n",
                  status, hw_mech, major_ver, minor_ver, pcibios_last_bus);
            if (status || signature != PCI_SIGNATURE) {
                  printk (KERN_ERR "PCI: BIOS BUG #%x[%08x] found\n",
                        status, signature);
                  return 0;
            }
            printk(KERN_INFO "PCI: PCI BIOS revision %x.%02x entry at 0x%lx, last bus=%d\n",
                  major_ver, minor_ver, pcibios_entry, pcibios_last_bus);
#ifdef CONFIG_PCI_DIRECT
            if (!(hw_mech & PCIBIOS_HW_TYPE1))
                  pci_probe &= ~PCI_PROBE_CONF1;
            if (!(hw_mech & PCIBIOS_HW_TYPE2))
                  pci_probe &= ~PCI_PROBE_CONF2;
#endif
            return 1;
      }
      return 0;
}

static int __devinit pci_bios_find_device (unsigned short vendor, unsigned short device_id,
                              unsigned short index, unsigned char *bus, unsigned char *device_fn)
{
      unsigned short bx;
      unsigned short ret;

      __asm__("lcall *(%%edi); cld\n\t"
            "jc 1f\n\t"
            "xor %%ah, %%ah\n"
            "1:"
            : "=b" (bx),
              "=a" (ret)
            : "1" (PCIBIOS_FIND_PCI_DEVICE),
              "c" (device_id),
              "d" (vendor),
              "S" ((int) index),
              "D" (&pci_indirect));
      *bus = (bx >> 8) & 0xff;
      *device_fn = bx & 0xff;
      return (int) (ret & 0xff00) >> 8;
}

static int pci_bios_read(unsigned int seg, unsigned int bus,
                   unsigned int devfn, int reg, int len, u32 *value)
{
      unsigned long result = 0;
      unsigned long flags;
      unsigned long bx = (bus << 8) | devfn;

      if (!value || (bus > 255) || (devfn > 255) || (reg > 255))
            return -EINVAL;

      spin_lock_irqsave(&pci_config_lock, flags);

      switch (len) {
      case 1:
            __asm__("lcall *(%%esi); cld\n\t"
                  "jc 1f\n\t"
                  "xor %%ah, %%ah\n"
                  "1:"
                  : "=c" (*value),
                    "=a" (result)
                  : "1" (PCIBIOS_READ_CONFIG_BYTE),
                    "b" (bx),
                    "D" ((long)reg),
                    "S" (&pci_indirect));
            break;
      case 2:
            __asm__("lcall *(%%esi); cld\n\t"
                  "jc 1f\n\t"
                  "xor %%ah, %%ah\n"
                  "1:"
                  : "=c" (*value),
                    "=a" (result)
                  : "1" (PCIBIOS_READ_CONFIG_WORD),
                    "b" (bx),
                    "D" ((long)reg),
                    "S" (&pci_indirect));
            break;
      case 4:
            __asm__("lcall *(%%esi); cld\n\t"
                  "jc 1f\n\t"
                  "xor %%ah, %%ah\n"
                  "1:"
                  : "=c" (*value),
                    "=a" (result)
                  : "1" (PCIBIOS_READ_CONFIG_DWORD),
                    "b" (bx),
                    "D" ((long)reg),
                    "S" (&pci_indirect));
            break;
      }

      spin_unlock_irqrestore(&pci_config_lock, flags);

      return (int)((result & 0xff00) >> 8);
}

static int pci_bios_write(unsigned int seg, unsigned int bus,
                    unsigned int devfn, int reg, int len, u32 value)
{
      unsigned long result = 0;
      unsigned long flags;
      unsigned long bx = (bus << 8) | devfn;

      if ((bus > 255) || (devfn > 255) || (reg > 255)) 
            return -EINVAL;

      spin_lock_irqsave(&pci_config_lock, flags);

      switch (len) {
      case 1:
            __asm__("lcall *(%%esi); cld\n\t"
                  "jc 1f\n\t"
                  "xor %%ah, %%ah\n"
                  "1:"
                  : "=a" (result)
                  : "0" (PCIBIOS_WRITE_CONFIG_BYTE),
                    "c" (value),
                    "b" (bx),
                    "D" ((long)reg),
                    "S" (&pci_indirect));
            break;
      case 2:
            __asm__("lcall *(%%esi); cld\n\t"
                  "jc 1f\n\t"
                  "xor %%ah, %%ah\n"
                  "1:"
                  : "=a" (result)
                  : "0" (PCIBIOS_WRITE_CONFIG_WORD),
                    "c" (value),
                    "b" (bx),
                    "D" ((long)reg),
                    "S" (&pci_indirect));
            break;
      case 4:
            __asm__("lcall *(%%esi); cld\n\t"
                  "jc 1f\n\t"
                  "xor %%ah, %%ah\n"
                  "1:"
                  : "=a" (result)
                  : "0" (PCIBIOS_WRITE_CONFIG_DWORD),
                    "c" (value),
                    "b" (bx),
                    "D" ((long)reg),
                    "S" (&pci_indirect));
            break;
      }

      spin_unlock_irqrestore(&pci_config_lock, flags);

      return (int)((result & 0xff00) >> 8);
}


/*
 * Function table for BIOS32 access
 */

static struct pci_raw_ops pci_bios_access = {
      .read =           pci_bios_read,
      .write =    pci_bios_write
};

/*
 * Try to find PCI BIOS.
 */

static struct pci_raw_ops * __devinit pci_find_bios(void)
{
      union bios32 *check;
      unsigned char sum;
      int i, length;

      /*
       * Follow the standard procedure for locating the BIOS32 Service
       * directory by scanning the permissible address range from
       * 0xe0000 through 0xfffff for a valid BIOS32 structure.
       */

      for (check = (union bios32 *) __va(0xe0000);
           check <= (union bios32 *) __va(0xffff0);
           ++check) {
            long sig;
            if (probe_kernel_address(&check->fields.signature, sig))
                  continue;

            if (check->fields.signature != BIOS32_SIGNATURE)
                  continue;
            length = check->fields.length * 16;
            if (!length)
                  continue;
            sum = 0;
            for (i = 0; i < length ; ++i)
                  sum += check->chars[i];
            if (sum != 0)
                  continue;
            if (check->fields.revision != 0) {
                  printk("PCI: unsupported BIOS32 revision %d at 0x%p\n",
                        check->fields.revision, check);
                  continue;
            }
            DBG("PCI: BIOS32 Service Directory structure at 0x%p\n", check);
            if (check->fields.entry >= 0x100000) {
                  printk("PCI: BIOS32 entry (0x%p) in high memory, "
                              "cannot use.\n", check);
                  return NULL;
            } else {
                  unsigned long bios32_entry = check->fields.entry;
                  DBG("PCI: BIOS32 Service Directory entry at 0x%lx\n",
                              bios32_entry);
                  bios32_indirect.address = bios32_entry + PAGE_OFFSET;
                  if (check_pcibios())
                        return &pci_bios_access;
            }
            break;      /* Hopefully more than one BIOS32 cannot happen... */
      }

      return NULL;
}

/*
 * Sort the device list according to PCI BIOS. Nasty hack, but since some
 * fool forgot to define the `correct' device order in the PCI BIOS specs
 * and we want to be (possibly bug-to-bug ;-]) compatible with older kernels
 * which used BIOS ordering, we are bound to do this...
 */

void __devinit pcibios_sort(void)
{
      LIST_HEAD(sorted_devices);
      struct list_head *ln;
      struct pci_dev *dev, *d;
      int idx, found;
      unsigned char bus, devfn;

      DBG("PCI: Sorting device list...\n");
      while (!list_empty(&pci_devices)) {
            ln = pci_devices.next;
            dev = pci_dev_g(ln);
            idx = found = 0;
            while (pci_bios_find_device(dev->vendor, dev->device, idx, &bus, &devfn) == PCIBIOS_SUCCESSFUL) {
                  idx++;
                  list_for_each(ln, &pci_devices) {
                        d = pci_dev_g(ln);
                        if (d->bus->number == bus && d->devfn == devfn) {
                              list_move_tail(&d->global_list, &sorted_devices);
                              if (d == dev)
                                    found = 1;
                              break;
                        }
                  }
                  if (ln == &pci_devices) {
                        printk(KERN_WARNING "PCI: BIOS reporting unknown device %02x:%02x\n", bus, devfn);
                        /*
                         * We must not continue scanning as several buggy BIOSes
                         * return garbage after the last device. Grr.
                         */
                        break;
                  }
            }
            if (!found) {
                  printk(KERN_WARNING "PCI: Device %s not found by BIOS\n",
                        pci_name(dev));
                  list_move_tail(&dev->global_list, &sorted_devices);
            }
      }
      list_splice(&sorted_devices, &pci_devices);
}

/*
 *  BIOS Functions for IRQ Routing
 */

struct irq_routing_options {
      u16 size;
      struct irq_info *table;
      u16 segment;
} __attribute__((packed));

struct irq_routing_table * pcibios_get_irq_routing_table(void)
{
      struct irq_routing_options opt;
      struct irq_routing_table *rt = NULL;
      int ret, map;
      unsigned long page;

      if (!pci_bios_present)
            return NULL;
      page = __get_free_page(GFP_KERNEL);
      if (!page)
            return NULL;
      opt.table = (struct irq_info *) page;
      opt.size = PAGE_SIZE;
      opt.segment = __KERNEL_DS;

      DBG("PCI: Fetching IRQ routing table... ");
      __asm__("push %%es\n\t"
            "push %%ds\n\t"
            "pop  %%es\n\t"
            "lcall *(%%esi); cld\n\t"
            "pop %%es\n\t"
            "jc 1f\n\t"
            "xor %%ah, %%ah\n"
            "1:"
            : "=a" (ret),
              "=b" (map),
              "=m" (opt)
            : "0" (PCIBIOS_GET_ROUTING_OPTIONS),
              "1" (0),
              "D" ((long) &opt),
              "S" (&pci_indirect),
              "m" (opt)
            : "memory");
      DBG("OK  ret=%d, size=%d, map=%x\n", ret, opt.size, map);
      if (ret & 0xff00)
            printk(KERN_ERR "PCI: Error %02x when fetching IRQ routing table.\n", (ret >> 8) & 0xff);
      else if (opt.size) {
            rt = kmalloc(sizeof(struct irq_routing_table) + opt.size, GFP_KERNEL);
            if (rt) {
                  memset(rt, 0, sizeof(struct irq_routing_table));
                  rt->size = opt.size + sizeof(struct irq_routing_table);
                  rt->exclusive_irqs = map;
                  memcpy(rt->slots, (void *) page, opt.size);
                  printk(KERN_INFO "PCI: Using BIOS Interrupt Routing Table\n");
            }
      }
      free_page(page);
      return rt;
}
EXPORT_SYMBOL(pcibios_get_irq_routing_table);

int pcibios_set_irq_routing(struct pci_dev *dev, int pin, int irq)
{
      int ret;

      __asm__("lcall *(%%esi); cld\n\t"
            "jc 1f\n\t"
            "xor %%ah, %%ah\n"
            "1:"
            : "=a" (ret)
            : "0" (PCIBIOS_SET_PCI_HW_INT),
              "b" ((dev->bus->number << 8) | dev->devfn),
              "c" ((irq << 8) | (pin + 10)),
              "S" (&pci_indirect));
      return !(ret & 0xff00);
}
EXPORT_SYMBOL(pcibios_set_irq_routing);

void __init pci_pcbios_init(void)
{
      if ((pci_probe & PCI_PROBE_BIOS) 
            && ((raw_pci_ops = pci_find_bios()))) {
            pci_probe |= PCI_BIOS_SORT;
            pci_bios_present = 1;
      }
}


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