#include <linux/types.h>
#include <linux/string.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/dmi.h>
#include <linux/efi.h>
#include <linux/bootmem.h>
#include <linux/slab.h>
#include <asm/dmi.h>

/*
 * DMI stands for "Desktop Management Interface".  It is part
 * of and an antecedent to, SMBIOS, which stands for System
 * Management BIOS.  See further: http://www.dmtf.org/standards
 */
static char dmi_empty_string[] = "        ";

/*
 * Catch too early calls to dmi_check_system():
 */
static int dmi_initialized;

static const char * __init dmi_string_nosave(const struct dmi_header *dm, u8 s)
{
        const u8 *bp = ((u8 *) dm) + dm->length;

        if (s) {
                s--;
                while (s > 0 && *bp) {
                        bp += strlen(bp) + 1;
                        s--;
                }

                if (*bp != 0) {
                        size_t len = strlen(bp)+1;
                        size_t cmp_len = len > 8 ? 8 : len;

                        if (!memcmp(bp, dmi_empty_string, cmp_len))
                                return dmi_empty_string;
                        return bp;
                }
        }

        return "";
}

static char * __init dmi_string(const struct dmi_header *dm, u8 s)
{
        const char *bp = dmi_string_nosave(dm, s);
        char *str;
        size_t len;

        if (bp == dmi_empty_string)
                return dmi_empty_string;

        len = strlen(bp) + 1;
        str = dmi_alloc(len);
        if (str != NULL)
                strcpy(str, bp);
        else
                printk(KERN_ERR "dmi_string: cannot allocate %Zu bytes.\n", len);

        return str;
}

/*
 *      We have to be cautious here. We have seen BIOSes with DMI pointers
 *      pointing to completely the wrong place for example
 */
static void dmi_table(u8 *buf, int len, int num,
                      void (*decode)(const struct dmi_header *, void *),
                      void *private_data)
{
        u8 *data = buf;
        int i = 0;

        /*
         *      Stop when we see all the items the table claimed to have
         *      OR we run off the end of the table (also happens)
         */
        while ((i < num) && (data - buf + sizeof(struct dmi_header)) <= len) {
                const struct dmi_header *dm = (const struct dmi_header *)data;

                /*
                 *  We want to know the total length (formatted area and
                 *  strings) before decoding to make sure we won't run off the
                 *  table in dmi_decode or dmi_string
                 */
                data += dm->length;
                while ((data - buf < len - 1) && (data[0] || data[1]))
                        data++;
                if (data - buf < len - 1)
                        decode(dm, private_data);
                data += 2;
                i++;
        }
}

static u32 dmi_base;
static u16 dmi_len;
static u16 dmi_num;

static int __init dmi_walk_early(void (*decode)(const struct dmi_header *,
                void *))
{
        u8 *buf;

        buf = dmi_ioremap(dmi_base, dmi_len);
        if (buf == NULL)
                return -1;

        dmi_table(buf, dmi_len, dmi_num, decode, NULL);

        dmi_iounmap(buf, dmi_len);
        return 0;
}

static int __init dmi_checksum(const u8 *buf)
{
        u8 sum = 0;
        int a;

        for (a = 0; a < 15; a++)
                sum += buf[a];

        return sum == 0;
}

static char *dmi_ident[DMI_STRING_MAX];
static LIST_HEAD(dmi_devices);
int dmi_available;

/*
 *      Save a DMI string
 */
static void __init dmi_save_ident(const struct dmi_header *dm, int slot, int string)
{
        const char *d = (const char*) dm;
        char *p;

        if (dmi_ident[slot])
                return;

        p = dmi_string(dm, d[string]);
        if (p == NULL)
                return;

        dmi_ident[slot] = p;
}

static void __init dmi_save_uuid(const struct dmi_header *dm, int slot, int index)
{
        const u8 *d = (u8*) dm + index;
        char *s;
        int is_ff = 1, is_00 = 1, i;

        if (dmi_ident[slot])
                return;

        for (i = 0; i < 16 && (is_ff || is_00); i++) {
                if(d[i] != 0x00) is_ff = 0;
                if(d[i] != 0xFF) is_00 = 0;
        }

        if (is_ff || is_00)
                return;

        s = dmi_alloc(16*2+4+1);
        if (!s)
                return;

        sprintf(s,
                "%02X%02X%02X%02X-%02X%02X-%02X%02X-%02X%02X-%02X%02X%02X%02X%02X%02X",
                d[0], d[1], d[2], d[3], d[4], d[5], d[6], d[7],
                d[8], d[9], d[10], d[11], d[12], d[13], d[14], d[15]);

        dmi_ident[slot] = s;
}

static void __init dmi_save_type(const struct dmi_header *dm, int slot, int index)
{
        const u8 *d = (u8*) dm + index;
        char *s;

        if (dmi_ident[slot])
                return;

        s = dmi_alloc(4);
        if (!s)
                return;

        sprintf(s, "%u", *d & 0x7F);
        dmi_ident[slot] = s;
}

static void __init dmi_save_one_device(int type, const char *name)
{
        struct dmi_device *dev;

        /* No duplicate device */
        if (dmi_find_device(type, name, NULL))
                return;

        dev = dmi_alloc(sizeof(*dev) + strlen(name) + 1);
        if (!dev) {
                printk(KERN_ERR "dmi_save_one_device: out of memory.\n");
                return;
        }

        dev->type = type;
        strcpy((char *)(dev + 1), name);
        dev->name = (char *)(dev + 1);
        dev->device_data = NULL;
        list_add(&dev->list, &dmi_devices);
}

static void __init dmi_save_devices(const struct dmi_header *dm)
{
        int i, count = (dm->length - sizeof(struct dmi_header)) / 2;

        for (i = 0; i < count; i++) {
                const char *d = (char *)(dm + 1) + (i * 2);

                /* Skip disabled device */
                if ((*d & 0x80) == 0)
                        continue;

                dmi_save_one_device(*d & 0x7f, dmi_string_nosave(dm, *(d + 1)));
        }
}

static void __init dmi_save_oem_strings_devices(const struct dmi_header *dm)
{
        int i, count = *(u8 *)(dm + 1);
        struct dmi_device *dev;

        for (i = 1; i <= count; i++) {
                char *devname = dmi_string(dm, i);

                if (devname == dmi_empty_string)
                        continue;

                dev = dmi_alloc(sizeof(*dev));
                if (!dev) {
                        printk(KERN_ERR
                           "dmi_save_oem_strings_devices: out of memory.\n");
                        break;
                }

                dev->type = DMI_DEV_TYPE_OEM_STRING;
                dev->name = devname;
                dev->device_data = NULL;

                list_add(&dev->list, &dmi_devices);
        }
}

static void __init dmi_save_ipmi_device(const struct dmi_header *dm)
{
        struct dmi_device *dev;
        void * data;

        data = dmi_alloc(dm->length);
        if (data == NULL) {
                printk(KERN_ERR "dmi_save_ipmi_device: out of memory.\n");
                return;
        }

        memcpy(data, dm, dm->length);

        dev = dmi_alloc(sizeof(*dev));
        if (!dev) {
                printk(KERN_ERR "dmi_save_ipmi_device: out of memory.\n");
                return;
        }

        dev->type = DMI_DEV_TYPE_IPMI;
        dev->name = "IPMI controller";
        dev->device_data = data;

        list_add_tail(&dev->list, &dmi_devices);
}

static void __init dmi_save_extended_devices(const struct dmi_header *dm)
{
        const u8 *d = (u8*) dm + 5;

        /* Skip disabled device */
        if ((*d & 0x80) == 0)
                return;

        dmi_save_one_device(*d & 0x7f, dmi_string_nosave(dm, *(d - 1)));
}

/*
 *      Process a DMI table entry. Right now all we care about are the BIOS
 *      and machine entries. For 2.5 we should pull the smbus controller info
 *      out of here.
 */
static void __init dmi_decode(const struct dmi_header *dm, void *dummy)
{
        switch(dm->type) {
        case 0:         /* BIOS Information */
                dmi_save_ident(dm, DMI_BIOS_VENDOR, 4);
                dmi_save_ident(dm, DMI_BIOS_VERSION, 5);
                dmi_save_ident(dm, DMI_BIOS_DATE, 8);
                break;
        case 1:         /* System Information */
                dmi_save_ident(dm, DMI_SYS_VENDOR, 4);
                dmi_save_ident(dm, DMI_PRODUCT_NAME, 5);
                dmi_save_ident(dm, DMI_PRODUCT_VERSION, 6);
                dmi_save_ident(dm, DMI_PRODUCT_SERIAL, 7);
                dmi_save_uuid(dm, DMI_PRODUCT_UUID, 8);
                break;
        case 2:         /* Base Board Information */
                dmi_save_ident(dm, DMI_BOARD_VENDOR, 4);
                dmi_save_ident(dm, DMI_BOARD_NAME, 5);
                dmi_save_ident(dm, DMI_BOARD_VERSION, 6);
                dmi_save_ident(dm, DMI_BOARD_SERIAL, 7);
                dmi_save_ident(dm, DMI_BOARD_ASSET_TAG, 8);
                break;
        case 3:         /* Chassis Information */
                dmi_save_ident(dm, DMI_CHASSIS_VENDOR, 4);
                dmi_save_type(dm, DMI_CHASSIS_TYPE, 5);
                dmi_save_ident(dm, DMI_CHASSIS_VERSION, 6);
                dmi_save_ident(dm, DMI_CHASSIS_SERIAL, 7);
                dmi_save_ident(dm, DMI_CHASSIS_ASSET_TAG, 8);
                break;
        case 10:        /* Onboard Devices Information */
                dmi_save_devices(dm);
                break;
        case 11:        /* OEM Strings */
                dmi_save_oem_strings_devices(dm);
                break;
        case 38:        /* IPMI Device Information */
                dmi_save_ipmi_device(dm);
                break;
        case 41:        /* Onboard Devices Extended Information */
                dmi_save_extended_devices(dm);
        }
}

static int __init dmi_present(const char __iomem *p)
{
        u8 buf[15];

        memcpy_fromio(buf, p, 15);
        if ((memcmp(buf, "_DMI_", 5) == 0) && dmi_checksum(buf)) {
                dmi_num = (buf[13] << 8) | buf[12];
                dmi_len = (buf[7] << 8) | buf[6];
                dmi_base = (buf[11] << 24) | (buf[10] << 16) |
                        (buf[9] << 8) | buf[8];

                /*
                 * DMI version 0.0 means that the real version is taken from
                 * the SMBIOS version, which we don't know at this point.
                 */
                if (buf[14] != 0)
                        printk(KERN_INFO "DMI %d.%d present.\n",
                               buf[14] >> 4, buf[14] & 0xF);
                else
                        printk(KERN_INFO "DMI present.\n");
                if (dmi_walk_early(dmi_decode) == 0)
                        return 0;
        }
        return 1;
}

void __init dmi_scan_machine(void)
{
        char __iomem *p, *q;
        int rc;

        if (efi_enabled) {
                if (efi.smbios == EFI_INVALID_TABLE_ADDR)
                        goto error;

                /* This is called as a core_initcall() because it isn't
                 * needed during early boot.  This also means we can
                 * iounmap the space when we're done with it.
                 */
                p = dmi_ioremap(efi.smbios, 32);
                if (p == NULL)
                        goto error;

                rc = dmi_present(p + 0x10); /* offset of _DMI_ string */
                dmi_iounmap(p, 32);
                if (!rc) {
                        dmi_available = 1;
                        goto out;
                }
        }
        else {
                /*
                 * no iounmap() for that ioremap(); it would be a no-op, but
                 * it's so early in setup that sucker gets confused into doing
                 * what it shouldn't if we actually call it.
                 */
                p = dmi_ioremap(0xF0000, 0x10000);
                if (p == NULL)
                        goto error;

                for (q = p; q < p + 0x10000; q += 16) {
                        rc = dmi_present(q);
                        if (!rc) {
                                dmi_available = 1;
                                dmi_iounmap(p, 0x10000);
                                goto out;
                        }
                }
                dmi_iounmap(p, 0x10000);
        }
 error:
        printk(KERN_INFO "DMI not present or invalid.\n");
 out:
        dmi_initialized = 1;
}

/**
 *      dmi_matches - check if dmi_system_id structure matches system DMI data
 *      @dmi: pointer to the dmi_system_id structure to check
 */
static bool dmi_matches(const struct dmi_system_id *dmi)
{
        int i;

        WARN(!dmi_initialized, KERN_ERR "dmi check: not initialized yet.\n");

        for (i = 0; i < ARRAY_SIZE(dmi->matches); i++) {
                int s = dmi->matches[i].slot;
                if (s == DMI_NONE)
                        continue;
                if (dmi_ident[s]
                    && strstr(dmi_ident[s], dmi->matches[i].substr))
                        continue;
                /* No match */
                return false;
        }
        return true;
}

/**
 *      dmi_check_system - check system DMI data
 *      @list: array of dmi_system_id structures to match against
 *              All non-null elements of the list must match
 *              their slot's (field index's) data (i.e., each
 *              list string must be a substring of the specified
 *              DMI slot's string data) to be considered a
 *              successful match.
 *
 *      Walk the blacklist table running matching functions until someone
 *      returns non zero or we hit the end. Callback function is called for
 *      each successful match. Returns the number of matches.
 */
int dmi_check_system(const struct dmi_system_id *list)
{
        int count = 0;
        const struct dmi_system_id *d;

        for (d = list; d->ident; d++)
                if (dmi_matches(d)) {
                        count++;
                        if (d->callback && d->callback(d))
                                break;
                }

        return count;
}
EXPORT_SYMBOL(dmi_check_system);

/**
 *      dmi_first_match - find dmi_system_id structure matching system DMI data
 *      @list: array of dmi_system_id structures to match against
 *              All non-null elements of the list must match
 *              their slot's (field index's) data (i.e., each
 *              list string must be a substring of the specified
 *              DMI slot's string data) to be considered a
 *              successful match.
 *
 *      Walk the blacklist table until the first match is found.  Return the
 *      pointer to the matching entry or NULL if there's no match.
 */
const struct dmi_system_id *dmi_first_match(const struct dmi_system_id *list)
{
        const struct dmi_system_id *d;

        for (d = list; d->ident; d++)
                if (dmi_matches(d))
                        return d;

        return NULL;
}
EXPORT_SYMBOL(dmi_first_match);

/**
 *      dmi_get_system_info - return DMI data value
 *      @field: data index (see enum dmi_field)
 *
 *      Returns one DMI data value, can be used to perform
 *      complex DMI data checks.
 */
const char *dmi_get_system_info(int field)
{
        return dmi_ident[field];
}
EXPORT_SYMBOL(dmi_get_system_info);

/**
 * dmi_name_in_serial - Check if string is in the DMI product serial information
 * @str: string to check for
 */
int dmi_name_in_serial(const char *str)
{
        int f = DMI_PRODUCT_SERIAL;
        if (dmi_ident[f] && strstr(dmi_ident[f], str))
                return 1;
        return 0;
}

/**
 *      dmi_name_in_vendors - Check if string is anywhere in the DMI vendor information.
 *      @str:   Case sensitive Name
 */
int dmi_name_in_vendors(const char *str)
{
        static int fields[] = { DMI_BIOS_VENDOR, DMI_BIOS_VERSION, DMI_SYS_VENDOR,
                                DMI_PRODUCT_NAME, DMI_PRODUCT_VERSION, DMI_BOARD_VENDOR,
                                DMI_BOARD_NAME, DMI_BOARD_VERSION, DMI_NONE };
        int i;
        for (i = 0; fields[i] != DMI_NONE; i++) {
                int f = fields[i];
                if (dmi_ident[f] && strstr(dmi_ident[f], str))
                        return 1;
        }
        return 0;
}
EXPORT_SYMBOL(dmi_name_in_vendors);

/**
 *      dmi_find_device - find onboard device by type/name
 *      @type: device type or %DMI_DEV_TYPE_ANY to match all device types
 *      @name: device name string or %NULL to match all
 *      @from: previous device found in search, or %NULL for new search.
 *
 *      Iterates through the list of known onboard devices. If a device is
 *      found with a matching @vendor and @device, a pointer to its device
 *      structure is returned.  Otherwise, %NULL is returned.
 *      A new search is initiated by passing %NULL as the @from argument.
 *      If @from is not %NULL, searches continue from next device.
 */
const struct dmi_device * dmi_find_device(int type, const char *name,
                                    const struct dmi_device *from)
{
        const struct list_head *head = from ? &from->list : &dmi_devices;
        struct list_head *d;

        for(d = head->next; d != &dmi_devices; d = d->next) {
                const struct dmi_device *dev =
                        list_entry(d, struct dmi_device, list);

                if (((type == DMI_DEV_TYPE_ANY) || (dev->type == type)) &&
                    ((name == NULL) || (strcmp(dev->name, name) == 0)))
                        return dev;
        }

        return NULL;
}
EXPORT_SYMBOL(dmi_find_device);

/**
 *      dmi_get_date - parse a DMI date
 *      @field: data index (see enum dmi_field)
 *      @yearp: optional out parameter for the year
 *      @monthp: optional out parameter for the month
 *      @dayp: optional out parameter for the day
 *
 *      The date field is assumed to be in the form resembling
 *      [mm[/dd]]/yy[yy] and the result is stored in the out
 *      parameters any or all of which can be omitted.
 *
 *      If the field doesn't exist, all out parameters are set to zero
 *      and false is returned.  Otherwise, true is returned with any
 *      invalid part of date set to zero.
 *
 *      On return, year, month and day are guaranteed to be in the
 *      range of [0,9999], [0,12] and [0,31] respectively.
 */
bool dmi_get_date(int field, int *yearp, int *monthp, int *dayp)
{
        int year = 0, month = 0, day = 0;
        bool exists;
        const char *s, *y;
        char *e;

        s = dmi_get_system_info(field);
        exists = s;
        if (!exists)
                goto out;

        /*
         * Determine year first.  We assume the date string resembles
         * mm/dd/yy[yy] but the original code extracted only the year
         * from the end.  Keep the behavior in the spirit of no
         * surprises.
         */
        y = strrchr(s, '/');
        if (!y)
                goto out;

        y++;
        year = simple_strtoul(y, &e, 10);
        if (y != e && year < 100) {     /* 2-digit year */
                year += 1900;
                if (year < 1996)        /* no dates < spec 1.0 */
                        year += 100;
        }
        if (year > 9999)                /* year should fit in %04d */
                year = 0;

        /* parse the mm and dd */
        month = simple_strtoul(s, &e, 10);
        if (s == e || *e != '/' || !month || month > 12) {
                month = 0;
                goto out;
        }

        s = e + 1;
        day = simple_strtoul(s, &e, 10);
        if (s == y || s == e || *e != '/' || day > 31)
                day = 0;
out:
        if (yearp)
                *yearp = year;
        if (monthp)
                *monthp = month;
        if (dayp)
                *dayp = day;
        return exists;
}
EXPORT_SYMBOL(dmi_get_date);

/**
 *      dmi_walk - Walk the DMI table and get called back for every record
 *      @decode: Callback function
 *      @private_data: Private data to be passed to the callback function
 *
 *      Returns -1 when the DMI table can't be reached, 0 on success.
 */
int dmi_walk(void (*decode)(const struct dmi_header *, void *),
             void *private_data)
{
        u8 *buf;

        if (!dmi_available)
                return -1;

        buf = ioremap(dmi_base, dmi_len);
        if (buf == NULL)
                return -1;

        dmi_table(buf, dmi_len, dmi_num, decode, private_data);

        iounmap(buf);
        return 0;
}
EXPORT_SYMBOL_GPL(dmi_walk);

/**
 * dmi_match - compare a string to the dmi field (if exists)
 * @f: DMI field identifier
 * @str: string to compare the DMI field to
 *
 * Returns true if the requested field equals to the str (including NULL).
 */
bool dmi_match(enum dmi_field f, const char *str)
{
        const char *info = dmi_get_system_info(f);

        if (info == NULL || str == NULL)
                return info == str;

        return !strcmp(info, str);
}
EXPORT_SYMBOL_GPL(dmi_match);