// SPDX-License-Identifier: GPL-2.0-only
// Copyright 2022 Google LLC
// Author: Ard Biesheuvel <ardb@google.com>

#include <linux/efi.h>

#include "efistub.h"

typedef union efi_smbios_protocol efi_smbios_protocol_t;

union efi_smbios_protocol {
        struct {
                efi_status_t (__efiapi *add)(efi_smbios_protocol_t *, efi_handle_t,
                                             u16 *, struct efi_smbios_record *);
                efi_status_t (__efiapi *update_string)(efi_smbios_protocol_t *, u16 *,
                                                       unsigned long *, u8 *);
                efi_status_t (__efiapi *remove)(efi_smbios_protocol_t *, u16);
                efi_status_t (__efiapi *get_next)(efi_smbios_protocol_t *, u16 *, u8 *,
                                                  struct efi_smbios_record **,
                                                  efi_handle_t *);

                u8 major_version;
                u8 minor_version;
        };
        struct {
                u32 add;
                u32 update_string;
                u32 remove;
                u32 get_next;

                u8 major_version;
                u8 minor_version;
        } mixed_mode;
};

const struct efi_smbios_record *efi_get_smbios_record(u8 type)
{
        struct efi_smbios_record *record;
        efi_smbios_protocol_t *smbios;
        efi_status_t status;
        u16 handle = 0xfffe;

        status = efi_bs_call(locate_protocol, &EFI_SMBIOS_PROTOCOL_GUID, NULL,
                             (void **)&smbios) ?:
                 efi_call_proto(smbios, get_next, &handle, &type, &record, NULL);
        if (status != EFI_SUCCESS)
                return NULL;
        return record;
}

const u8 *__efi_get_smbios_string(const struct efi_smbios_record *record,
                                  const u8 *offset)
{
        const u8 *strtable;

        if (!record)
                return NULL;

        strtable = (u8 *)record + record->length;
        for (int i = 1; i < *offset; i++) {
                int len = strlen(strtable);

                if (!len)
                        return NULL;
                strtable += len + 1;
        }
        return strtable;
}