// SPDX-License-Identifier: GPL-2.0-only
/*
 *  PS3 flash memory os area.
 *
 *  Copyright (C) 2006 Sony Computer Entertainment Inc.
 *  Copyright 2006 Sony Corp.
 */

#include <linux/kernel.h>
#include <linux/io.h>
#include <linux/workqueue.h>
#include <linux/fs.h>
#include <linux/syscalls.h>
#include <linux/export.h>
#include <linux/ctype.h>
#include <linux/memblock.h>
#include <linux/of.h>
#include <linux/slab.h>

#include "platform.h"

enum {
        OS_AREA_SEGMENT_SIZE = 0X200,
};

enum os_area_ldr_format {
        HEADER_LDR_FORMAT_RAW = 0,
        HEADER_LDR_FORMAT_GZIP = 1,
};

#define OS_AREA_HEADER_MAGIC_NUM "cell_ext_os_area"

/**
 * struct os_area_header - os area header segment.
 * @magic_num: Always 'cell_ext_os_area'.
 * @hdr_version: Header format version number.
 * @db_area_offset: Starting segment number of other os database area.
 * @ldr_area_offset: Starting segment number of bootloader image area.
 * @ldr_format: HEADER_LDR_FORMAT flag.
 * @ldr_size: Size of bootloader image in bytes.
 *
 * Note that the docs refer to area offsets.  These are offsets in units of
 * segments from the start of the os area (top of the header).  These are
 * better thought of as segment numbers.  The os area of the os area is
 * reserved for the os image.
 */

struct os_area_header {
        u8 magic_num[16];
        u32 hdr_version;
        u32 db_area_offset;
        u32 ldr_area_offset;
        u32 _reserved_1;
        u32 ldr_format;
        u32 ldr_size;
        u32 _reserved_2[6];
};

enum os_area_boot_flag {
        PARAM_BOOT_FLAG_GAME_OS = 0,
        PARAM_BOOT_FLAG_OTHER_OS = 1,
};

enum os_area_ctrl_button {
        PARAM_CTRL_BUTTON_O_IS_YES = 0,
        PARAM_CTRL_BUTTON_X_IS_YES = 1,
};

/**
 * struct os_area_params - os area params segment.
 * @boot_flag: User preference of operating system, PARAM_BOOT_FLAG flag.
 * @num_params: Number of params in this (params) segment.
 * @rtc_diff: Difference in seconds between 1970 and the ps3 rtc value.
 * @av_multi_out: User preference of AV output, PARAM_AV_MULTI_OUT flag.
 * @ctrl_button: User preference of controller button config, PARAM_CTRL_BUTTON
 *      flag.
 * @static_ip_addr: User preference of static IP address.
 * @network_mask: User preference of static network mask.
 * @default_gateway: User preference of static default gateway.
 * @dns_primary: User preference of static primary dns server.
 * @dns_secondary: User preference of static secondary dns server.
 *
 * The ps3 rtc maintains a read-only value that approximates seconds since
 * 2000-01-01 00:00:00 UTC.
 *
 * User preference of zero for static_ip_addr means use dhcp.
 */

struct os_area_params {
        u32 boot_flag;
        u32 _reserved_1[3];
        u32 num_params;
        u32 _reserved_2[3];
        /* param 0 */
        s64 rtc_diff;
        u8 av_multi_out;
        u8 ctrl_button;
        u8 _reserved_3[6];
        /* param 1 */
        u8 static_ip_addr[4];
        u8 network_mask[4];
        u8 default_gateway[4];
        u8 _reserved_4[4];
        /* param 2 */
        u8 dns_primary[4];
        u8 dns_secondary[4];
        u8 _reserved_5[8];
};

#define OS_AREA_DB_MAGIC_NUM "-db-"

/**
 * struct os_area_db - Shared flash memory database.
 * @magic_num: Always '-db-'.
 * @version: os_area_db format version number.
 * @index_64: byte offset of the database id index for 64 bit variables.
 * @count_64: number of usable 64 bit index entries
 * @index_32: byte offset of the database id index for 32 bit variables.
 * @count_32: number of usable 32 bit index entries
 * @index_16: byte offset of the database id index for 16 bit variables.
 * @count_16: number of usable 16 bit index entries
 *
 * Flash rom storage for exclusive use by guests running in the other os lpar.
 * The current system configuration allocates 1K (two segments) for other os
 * use.
 */

struct os_area_db {
        u8 magic_num[4];
        u16 version;
        u16 _reserved_1;
        u16 index_64;
        u16 count_64;
        u16 index_32;
        u16 count_32;
        u16 index_16;
        u16 count_16;
        u32 _reserved_2;
        u8 _db_data[1000];
};

/**
 * enum os_area_db_owner - Data owners.
 */

enum os_area_db_owner {
        OS_AREA_DB_OWNER_ANY = -1,
        OS_AREA_DB_OWNER_NONE = 0,
        OS_AREA_DB_OWNER_PROTOTYPE = 1,
        OS_AREA_DB_OWNER_LINUX = 2,
        OS_AREA_DB_OWNER_PETITBOOT = 3,
        OS_AREA_DB_OWNER_MAX = 32,
};

enum os_area_db_key {
        OS_AREA_DB_KEY_ANY = -1,
        OS_AREA_DB_KEY_NONE = 0,
        OS_AREA_DB_KEY_RTC_DIFF = 1,
        OS_AREA_DB_KEY_VIDEO_MODE = 2,
        OS_AREA_DB_KEY_MAX = 8,
};

struct os_area_db_id {
        int owner;
        int key;
};

static const struct os_area_db_id os_area_db_id_empty = {
        .owner = OS_AREA_DB_OWNER_NONE,
        .key = OS_AREA_DB_KEY_NONE
};

static const struct os_area_db_id os_area_db_id_any = {
        .owner = OS_AREA_DB_OWNER_ANY,
        .key = OS_AREA_DB_KEY_ANY
};

static const struct os_area_db_id os_area_db_id_rtc_diff = {
        .owner = OS_AREA_DB_OWNER_LINUX,
        .key = OS_AREA_DB_KEY_RTC_DIFF
};

#define SECONDS_FROM_1970_TO_2000 946684800LL

/**
 * struct saved_params - Static working copies of data from the PS3 'os area'.
 *
 * The order of preference we use for the rtc_diff source:
 *  1) The database value.
 *  2) The game os value.
 *  3) The number of seconds from 1970 to 2000.
 */

static struct saved_params {
        unsigned int valid;
        s64 rtc_diff;
        unsigned int av_multi_out;
} saved_params;

static struct property property_rtc_diff = {
        .name = "linux,rtc_diff",
        .length = sizeof(saved_params.rtc_diff),
        .value = &saved_params.rtc_diff,
};

static struct property property_av_multi_out = {
        .name = "linux,av_multi_out",
        .length = sizeof(saved_params.av_multi_out),
        .value = &saved_params.av_multi_out,
};


static DEFINE_MUTEX(os_area_flash_mutex);

static const struct ps3_os_area_flash_ops *os_area_flash_ops;

void ps3_os_area_flash_register(const struct ps3_os_area_flash_ops *ops)
{
        mutex_lock(&os_area_flash_mutex);
        os_area_flash_ops = ops;
        mutex_unlock(&os_area_flash_mutex);
}
EXPORT_SYMBOL_GPL(ps3_os_area_flash_register);

static ssize_t os_area_flash_read(void *buf, size_t count, loff_t pos)
{
        ssize_t res = -ENODEV;

        mutex_lock(&os_area_flash_mutex);
        if (os_area_flash_ops)
                res = os_area_flash_ops->read(buf, count, pos);
        mutex_unlock(&os_area_flash_mutex);

        return res;
}

static ssize_t os_area_flash_write(const void *buf, size_t count, loff_t pos)
{
        ssize_t res = -ENODEV;

        mutex_lock(&os_area_flash_mutex);
        if (os_area_flash_ops)
                res = os_area_flash_ops->write(buf, count, pos);
        mutex_unlock(&os_area_flash_mutex);

        return res;
}


/**
 * os_area_set_property - Add or overwrite a saved_params value to the device tree.
 *
 * Overwrites an existing property.
 */

static void os_area_set_property(struct device_node *node,
        struct property *prop)
{
        int result;
        struct property *tmp = of_find_property(node, prop->name, NULL);

        if (tmp) {
                pr_debug("%s:%d found %s\n", __func__, __LINE__, prop->name);
                of_remove_property(node, tmp);
        }

        result = of_add_property(node, prop);

        if (result)
                pr_debug("%s:%d of_set_property failed\n", __func__,
                        __LINE__);
}

/**
 * os_area_get_property - Get a saved_params value from the device tree.
 *
 */

static void __init os_area_get_property(struct device_node *node,
        struct property *prop)
{
        const struct property *tmp = of_find_property(node, prop->name, NULL);

        if (tmp) {
                BUG_ON(prop->length != tmp->length);
                memcpy(prop->value, tmp->value, prop->length);
        } else
                pr_debug("%s:%d not found %s\n", __func__, __LINE__,
                        prop->name);
}

static void dump_field(char *s, const u8 *field, int size_of_field)
{
#if defined(DEBUG)
        int i;

        for (i = 0; i < size_of_field; i++)
                s[i] = isprint(field[i]) ? field[i] : '.';
        s[i] = 0;
#endif
}

#define dump_header(_a) _dump_header(_a, __func__, __LINE__)
static void _dump_header(const struct os_area_header *h, const char *func,
        int line)
{
        char str[sizeof(h->magic_num) + 1];

        dump_field(str, h->magic_num, sizeof(h->magic_num));
        pr_debug("%s:%d: h.magic_num:       '%s'\n", func, line,
                str);
        pr_debug("%s:%d: h.hdr_version:     %u\n", func, line,
                h->hdr_version);
        pr_debug("%s:%d: h.db_area_offset:  %u\n", func, line,
                h->db_area_offset);
        pr_debug("%s:%d: h.ldr_area_offset: %u\n", func, line,
                h->ldr_area_offset);
        pr_debug("%s:%d: h.ldr_format:      %u\n", func, line,
                h->ldr_format);
        pr_debug("%s:%d: h.ldr_size:        %xh\n", func, line,
                h->ldr_size);
}

#define dump_params(_a) _dump_params(_a, __func__, __LINE__)
static void _dump_params(const struct os_area_params *p, const char *func,
        int line)
{
        pr_debug("%s:%d: p.boot_flag:       %u\n", func, line, p->boot_flag);
        pr_debug("%s:%d: p.num_params:      %u\n", func, line, p->num_params);
        pr_debug("%s:%d: p.rtc_diff         %lld\n", func, line, p->rtc_diff);
        pr_debug("%s:%d: p.av_multi_out     %u\n", func, line, p->av_multi_out);
        pr_debug("%s:%d: p.ctrl_button:     %u\n", func, line, p->ctrl_button);
        pr_debug("%s:%d: p.static_ip_addr:  %u.%u.%u.%u\n", func, line,
                p->static_ip_addr[0], p->static_ip_addr[1],
                p->static_ip_addr[2], p->static_ip_addr[3]);
        pr_debug("%s:%d: p.network_mask:    %u.%u.%u.%u\n", func, line,
                p->network_mask[0], p->network_mask[1],
                p->network_mask[2], p->network_mask[3]);
        pr_debug("%s:%d: p.default_gateway: %u.%u.%u.%u\n", func, line,
                p->default_gateway[0], p->default_gateway[1],
                p->default_gateway[2], p->default_gateway[3]);
        pr_debug("%s:%d: p.dns_primary:     %u.%u.%u.%u\n", func, line,
                p->dns_primary[0], p->dns_primary[1],
                p->dns_primary[2], p->dns_primary[3]);
        pr_debug("%s:%d: p.dns_secondary:   %u.%u.%u.%u\n", func, line,
                p->dns_secondary[0], p->dns_secondary[1],
                p->dns_secondary[2], p->dns_secondary[3]);
}

static int verify_header(const struct os_area_header *header)
{
        if (memcmp(header->magic_num, OS_AREA_HEADER_MAGIC_NUM,
                sizeof(header->magic_num))) {
                pr_debug("%s:%d magic_num failed\n", __func__, __LINE__);
                return -1;
        }

        if (header->hdr_version < 1) {
                pr_debug("%s:%d hdr_version failed\n", __func__, __LINE__);
                return -1;
        }

        if (header->db_area_offset > header->ldr_area_offset) {
                pr_debug("%s:%d offsets failed\n", __func__, __LINE__);
                return -1;
        }

        return 0;
}

static int db_verify(const struct os_area_db *db)
{
        if (memcmp(db->magic_num, OS_AREA_DB_MAGIC_NUM,
                sizeof(db->magic_num))) {
                pr_debug("%s:%d magic_num failed\n", __func__, __LINE__);
                return -EINVAL;
        }

        if (db->version != 1) {
                pr_debug("%s:%d version failed\n", __func__, __LINE__);
                return -EINVAL;
        }

        return 0;
}

struct db_index {
       uint8_t owner:5;
       uint8_t key:3;
};

struct db_iterator {
        const struct os_area_db *db;
        struct os_area_db_id match_id;
        struct db_index *idx;
        struct db_index *last_idx;
        union {
                uint64_t *value_64;
                uint32_t *value_32;
                uint16_t *value_16;
        };
};

static unsigned int db_align_up(unsigned int val, unsigned int size)
{
        return (val + (size - 1)) & (~(size - 1));
}

/**
 * db_for_each_64 - Iterator for 64 bit entries.
 *
 * A NULL value for id can be used to match all entries.
 * OS_AREA_DB_OWNER_ANY and OS_AREA_DB_KEY_ANY can be used to match all.
 */

static int db_for_each_64(const struct os_area_db *db,
        const struct os_area_db_id *match_id, struct db_iterator *i)
{
next:
        if (!i->db) {
                i->db = db;
                i->match_id = match_id ? *match_id : os_area_db_id_any;
                i->idx = (void *)db + db->index_64;
                i->last_idx = i->idx + db->count_64;
                i->value_64 = (void *)db + db->index_64
                        + db_align_up(db->count_64, 8);
        } else {
                i->idx++;
                i->value_64++;
        }

        if (i->idx >= i->last_idx) {
                pr_debug("%s:%d: reached end\n", __func__, __LINE__);
                return 0;
        }

        if (i->match_id.owner != OS_AREA_DB_OWNER_ANY
                && i->match_id.owner != (int)i->idx->owner)
                goto next;
        if (i->match_id.key != OS_AREA_DB_KEY_ANY
                && i->match_id.key != (int)i->idx->key)
                goto next;

        return 1;
}

static int db_delete_64(struct os_area_db *db, const struct os_area_db_id *id)
{
        struct db_iterator i;

        for (i.db = NULL; db_for_each_64(db, id, &i); ) {

                pr_debug("%s:%d: got (%d:%d) %llxh\n", __func__, __LINE__,
                        i.idx->owner, i.idx->key,
                        (unsigned long long)*i.value_64);

                i.idx->owner = 0;
                i.idx->key = 0;
                *i.value_64 = 0;
        }
        return 0;
}

static int db_set_64(struct os_area_db *db, const struct os_area_db_id *id,
        uint64_t value)
{
        struct db_iterator i;

        pr_debug("%s:%d: (%d:%d) <= %llxh\n", __func__, __LINE__,
                id->owner, id->key, (unsigned long long)value);

        if (!id->owner || id->owner == OS_AREA_DB_OWNER_ANY
                || id->key == OS_AREA_DB_KEY_ANY) {
                pr_debug("%s:%d: bad id: (%d:%d)\n", __func__,
                        __LINE__, id->owner, id->key);
                return -1;
        }

        db_delete_64(db, id);

        i.db = NULL;
        if (db_for_each_64(db, &os_area_db_id_empty, &i)) {

                pr_debug("%s:%d: got (%d:%d) %llxh\n", __func__, __LINE__,
                        i.idx->owner, i.idx->key,
                        (unsigned long long)*i.value_64);

                i.idx->owner = id->owner;
                i.idx->key = id->key;
                *i.value_64 = value;

                pr_debug("%s:%d: set (%d:%d) <= %llxh\n", __func__, __LINE__,
                        i.idx->owner, i.idx->key,
                        (unsigned long long)*i.value_64);
                return 0;
        }
        pr_debug("%s:%d: database full.\n",
                __func__, __LINE__);
        return -1;
}

static int __init db_get_64(const struct os_area_db *db,
        const struct os_area_db_id *id, uint64_t *value)
{
        struct db_iterator i;

        i.db = NULL;
        if (db_for_each_64(db, id, &i)) {
                *value = *i.value_64;
                pr_debug("%s:%d: found %lld\n", __func__, __LINE__,
                                (long long int)*i.value_64);
                return 0;
        }
        pr_debug("%s:%d: not found\n", __func__, __LINE__);
        return -1;
}

static int __init db_get_rtc_diff(const struct os_area_db *db, int64_t *rtc_diff)
{
        return db_get_64(db, &os_area_db_id_rtc_diff, (uint64_t*)rtc_diff);
}

#define dump_db(a) _dump_db(a, __func__, __LINE__)
static void _dump_db(const struct os_area_db *db, const char *func,
        int line)
{
        char str[sizeof(db->magic_num) + 1];

        dump_field(str, db->magic_num, sizeof(db->magic_num));
        pr_debug("%s:%d: db.magic_num:      '%s'\n", func, line,
                str);
        pr_debug("%s:%d: db.version:         %u\n", func, line,
                db->version);
        pr_debug("%s:%d: db.index_64:        %u\n", func, line,
                db->index_64);
        pr_debug("%s:%d: db.count_64:        %u\n", func, line,
                db->count_64);
        pr_debug("%s:%d: db.index_32:        %u\n", func, line,
                db->index_32);
        pr_debug("%s:%d: db.count_32:        %u\n", func, line,
                db->count_32);
        pr_debug("%s:%d: db.index_16:        %u\n", func, line,
                db->index_16);
        pr_debug("%s:%d: db.count_16:        %u\n", func, line,
                db->count_16);
}

static void os_area_db_init(struct os_area_db *db)
{
        enum {
                HEADER_SIZE = offsetof(struct os_area_db, _db_data),
                INDEX_64_COUNT = 64,
                VALUES_64_COUNT = 57,
                INDEX_32_COUNT = 64,
                VALUES_32_COUNT = 57,
                INDEX_16_COUNT = 64,
                VALUES_16_COUNT = 57,
        };

        memset(db, 0, sizeof(struct os_area_db));

        memcpy(db->magic_num, OS_AREA_DB_MAGIC_NUM, sizeof(db->magic_num));
        db->version = 1;
        db->index_64 = HEADER_SIZE;
        db->count_64 = VALUES_64_COUNT;
        db->index_32 = HEADER_SIZE
                        + INDEX_64_COUNT * sizeof(struct db_index)
                        + VALUES_64_COUNT * sizeof(u64);
        db->count_32 = VALUES_32_COUNT;
        db->index_16 = HEADER_SIZE
                        + INDEX_64_COUNT * sizeof(struct db_index)
                        + VALUES_64_COUNT * sizeof(u64)
                        + INDEX_32_COUNT * sizeof(struct db_index)
                        + VALUES_32_COUNT * sizeof(u32);
        db->count_16 = VALUES_16_COUNT;

        /* Rules to check db layout. */

        BUILD_BUG_ON(sizeof(struct db_index) != 1);
        BUILD_BUG_ON(sizeof(struct os_area_db) != 2 * OS_AREA_SEGMENT_SIZE);
        BUILD_BUG_ON(INDEX_64_COUNT & 0x7);
        BUILD_BUG_ON(VALUES_64_COUNT > INDEX_64_COUNT);
        BUILD_BUG_ON(INDEX_32_COUNT & 0x7);
        BUILD_BUG_ON(VALUES_32_COUNT > INDEX_32_COUNT);
        BUILD_BUG_ON(INDEX_16_COUNT & 0x7);
        BUILD_BUG_ON(VALUES_16_COUNT > INDEX_16_COUNT);
        BUILD_BUG_ON(HEADER_SIZE
                        + INDEX_64_COUNT * sizeof(struct db_index)
                        + VALUES_64_COUNT * sizeof(u64)
                        + INDEX_32_COUNT * sizeof(struct db_index)
                        + VALUES_32_COUNT * sizeof(u32)
                        + INDEX_16_COUNT * sizeof(struct db_index)
                        + VALUES_16_COUNT * sizeof(u16)
                        > sizeof(struct os_area_db));
}

/**
 * update_flash_db - Helper for os_area_queue_work_handler.
 *
 */

static int update_flash_db(void)
{
        const unsigned int buf_len = 8 * OS_AREA_SEGMENT_SIZE;
        struct os_area_header *header;
        ssize_t count;
        int error;
        loff_t pos;
        struct os_area_db* db;

        /* Read in header and db from flash. */

        header = kmalloc(buf_len, GFP_KERNEL);
        if (!header)
                return -ENOMEM;

        count = os_area_flash_read(header, buf_len, 0);
        if (count < 0) {
                pr_debug("%s: os_area_flash_read failed %zd\n", __func__,
                         count);
                error = count;
                goto fail;
        }

        pos = header->db_area_offset * OS_AREA_SEGMENT_SIZE;
        if (count < OS_AREA_SEGMENT_SIZE || verify_header(header) ||
            count < pos) {
                pr_debug("%s: verify_header failed\n", __func__);
                dump_header(header);
                error = -EINVAL;
                goto fail;
        }

        /* Now got a good db offset and some maybe good db data. */

        db = (void *)header + pos;

        error = db_verify(db);
        if (error) {
                pr_notice("%s: Verify of flash database failed, formatting.\n",
                          __func__);
                dump_db(db);
                os_area_db_init(db);
        }

        /* Now got good db data. */

        db_set_64(db, &os_area_db_id_rtc_diff, saved_params.rtc_diff);

        count = os_area_flash_write(db, sizeof(struct os_area_db), pos);
        if (count < 0 || count < sizeof(struct os_area_db)) {
                pr_debug("%s: os_area_flash_write failed %zd\n", __func__,
                         count);
                error = count < 0 ? count : -EIO;
        }

fail:
        kfree(header);
        return error;
}

/**
 * os_area_queue_work_handler - Asynchronous write handler.
 *
 * An asynchronous write for flash memory and the device tree.  Do not
 * call directly, use os_area_queue_work().
 */

static void os_area_queue_work_handler(struct work_struct *work)
{
        struct device_node *node;
        int error;

        pr_debug(" -> %s:%d\n", __func__, __LINE__);

        node = of_find_node_by_path("/");
        if (node) {
                os_area_set_property(node, &property_rtc_diff);
                of_node_put(node);
        } else
                pr_debug("%s:%d of_find_node_by_path failed\n",
                        __func__, __LINE__);

        error = update_flash_db();
        if (error)
                pr_warn("%s: Could not update FLASH ROM\n", __func__);

        pr_debug(" <- %s:%d\n", __func__, __LINE__);
}

static void os_area_queue_work(void)
{
        static DECLARE_WORK(q, os_area_queue_work_handler);

        wmb();
        schedule_work(&q);
}

/**
 * ps3_os_area_save_params - Copy data from os area mirror to @saved_params.
 *
 * For the convenience of the guest the HV makes a copy of the os area in
 * flash to a high address in the boot memory region and then puts that RAM
 * address and the byte count into the repository for retrieval by the guest.
 * We copy the data we want into a static variable and allow the memory setup
 * by the HV to be claimed by the memblock manager.
 *
 * The os area mirror will not be available to a second stage kernel, and
 * the header verify will fail.  In this case, the saved_params values will
 * be set from flash memory or the passed in device tree in ps3_os_area_init().
 */

void __init ps3_os_area_save_params(void)
{
        int result;
        u64 lpar_addr;
        unsigned int size;
        struct os_area_header *header;
        struct os_area_params *params;
        struct os_area_db *db;

        pr_debug(" -> %s:%d\n", __func__, __LINE__);

        result = ps3_repository_read_boot_dat_info(&lpar_addr, &size);

        if (result) {
                pr_debug("%s:%d ps3_repository_read_boot_dat_info failed\n",
                        __func__, __LINE__);
                return;
        }

        header = (struct os_area_header *)__va(lpar_addr);
        params = (struct os_area_params *)__va(lpar_addr
                + OS_AREA_SEGMENT_SIZE);

        result = verify_header(header);

        if (result) {
                /* Second stage kernels exit here. */
                pr_debug("%s:%d verify_header failed\n", __func__, __LINE__);
                dump_header(header);
                return;
        }

        db = (struct os_area_db *)__va(lpar_addr
                + header->db_area_offset * OS_AREA_SEGMENT_SIZE);

        dump_header(header);
        dump_params(params);
        dump_db(db);

        result = db_verify(db) || db_get_rtc_diff(db, &saved_params.rtc_diff);
        if (result)
                saved_params.rtc_diff = params->rtc_diff ? params->rtc_diff
                        : SECONDS_FROM_1970_TO_2000;
        saved_params.av_multi_out = params->av_multi_out;
        saved_params.valid = 1;

        memset(header, 0, sizeof(*header));

        pr_debug(" <- %s:%d\n", __func__, __LINE__);
}

/**
 * ps3_os_area_init - Setup os area device tree properties as needed.
 */

void __init ps3_os_area_init(void)
{
        struct device_node *node;

        pr_debug(" -> %s:%d\n", __func__, __LINE__);

        node = of_find_node_by_path("/");

        if (!saved_params.valid && node) {
                /* Second stage kernels should have a dt entry. */
                os_area_get_property(node, &property_rtc_diff);
                os_area_get_property(node, &property_av_multi_out);
        }

        if(!saved_params.rtc_diff)
                saved_params.rtc_diff = SECONDS_FROM_1970_TO_2000;

        if (node) {
                os_area_set_property(node, &property_rtc_diff);
                os_area_set_property(node, &property_av_multi_out);
                of_node_put(node);
        } else
                pr_debug("%s:%d of_find_node_by_path failed\n",
                        __func__, __LINE__);

        pr_debug(" <- %s:%d\n", __func__, __LINE__);
}

/**
 * ps3_os_area_get_rtc_diff - Returns the rtc diff value.
 */

u64 ps3_os_area_get_rtc_diff(void)
{
        return saved_params.rtc_diff;
}
EXPORT_SYMBOL_GPL(ps3_os_area_get_rtc_diff);

/**
 * ps3_os_area_set_rtc_diff - Set the rtc diff value.
 *
 * An asynchronous write is needed to support writing updates from
 * the timer interrupt context.
 */

void ps3_os_area_set_rtc_diff(u64 rtc_diff)
{
        if (saved_params.rtc_diff != rtc_diff) {
                saved_params.rtc_diff = rtc_diff;
                os_area_queue_work();
        }
}
EXPORT_SYMBOL_GPL(ps3_os_area_set_rtc_diff);

/**
 * ps3_os_area_get_av_multi_out - Returns the default video mode.
 */

enum ps3_param_av_multi_out ps3_os_area_get_av_multi_out(void)
{
    return saved_params.av_multi_out;
}
EXPORT_SYMBOL_GPL(ps3_os_area_get_av_multi_out);