/*
 * 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 * __devinit 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;
        }
}