// SPDX-License-Identifier: GPL-2.0+
/*
 * Copyright (c) 2017 Intel Corporation
 */

#include <common.h>
#include <init.h>
#include <log.h>
#include <asm/e820.h>
#include <asm/global_data.h>
#include <asm/sfi.h>

DECLARE_GLOBAL_DATA_PTR;

/*
 * SFI tables are part of the first stage bootloader.
 *
 * U-Boot finds the System Table by searching 16-byte boundaries between
 * physical address 0x000E0000 and 0x000FFFFF. U-Boot shall search this region
 * starting at the low address and shall stop searching when the 1st valid SFI
 * System Table is found.
 */
#define SFI_BASE_ADDR           0x000E0000
#define SFI_LENGTH              0x00020000
#define SFI_TABLE_LENGTH        16

static int sfi_table_check(struct sfi_table_header *sbh)
{
        char chksum = 0;
        char *pos = (char *)sbh;
        u32 i;

        if (sbh->len < SFI_TABLE_LENGTH)
                return -ENXIO;

        if (sbh->len > SFI_LENGTH)
                return -ENXIO;

        for (i = 0; i < sbh->len; i++)
                chksum += *pos++;

        if (chksum)
                pr_err("sfi: Invalid checksum\n");

        /* Checksum is OK if zero */
        return chksum ? -EILSEQ : 0;
}

static int sfi_table_is_type(struct sfi_table_header *sbh, const char *signature)
{
        return !strncmp(sbh->sig, signature, SFI_SIGNATURE_SIZE) &&
               !sfi_table_check(sbh);
}

static struct sfi_table_simple *sfi_get_table_by_sig(unsigned long addr,
                                                     const char *signature)
{
        struct sfi_table_simple *sb;
        u32 i;

        for (i = 0; i < SFI_LENGTH; i += SFI_TABLE_LENGTH) {
                sb = (struct sfi_table_simple *)(addr + i);
                if (sfi_table_is_type(&sb->header, signature))
                        return sb;
        }

        return NULL;
}

static struct sfi_table_simple *sfi_search_mmap(void)
{
        struct sfi_table_header *sbh;
        struct sfi_table_simple *sb;
        u32 sys_entry_cnt;
        u32 i;

        /* Find SYST table */
        sb = sfi_get_table_by_sig(SFI_BASE_ADDR, SFI_SIG_SYST);
        if (!sb) {
                pr_err("sfi: failed to locate SYST table\n");
                return NULL;
        }

        sys_entry_cnt = (sb->header.len - sizeof(*sbh)) / 8;

        /* Search through each SYST entry for MMAP table */
        for (i = 0; i < sys_entry_cnt; i++) {
                sbh = (struct sfi_table_header *)(unsigned long)sb->pentry[i];

                if (sfi_table_is_type(sbh, SFI_SIG_MMAP))
                        return (struct sfi_table_simple *)sbh;
        }

        pr_err("sfi: failed to locate SFI MMAP table\n");
        return NULL;
}

#define sfi_for_each_mentry(i, sb, mentry)                              \
        for (i = 0, mentry = (struct sfi_mem_entry *)sb->pentry;        \
             i < SFI_GET_NUM_ENTRIES(sb, struct sfi_mem_entry);         \
             i++, mentry++)                                             \

static unsigned int sfi_setup_e820(unsigned int max_entries,
                                   struct e820_entry *entries)
{
        struct sfi_table_simple *sb;
        struct sfi_mem_entry *mentry;
        unsigned long long start, end, size;
        int type, total = 0;
        u32 i;

        sb = sfi_search_mmap();
        if (!sb)
                return 0;

        sfi_for_each_mentry(i, sb, mentry) {
                start = mentry->phys_start;
                size = mentry->pages << 12;
                end = start + size;

                if (start > end)
                        continue;

                /* translate SFI mmap type to E820 map type */
                switch (mentry->type) {
                case SFI_MEM_CONV:
                        type = E820_RAM;
                        break;
                case SFI_MEM_UNUSABLE:
                case SFI_RUNTIME_SERVICE_DATA:
                        continue;
                default:
                        type = E820_RESERVED;
                }

                if (total == E820MAX)
                        break;
                entries[total].addr = start;
                entries[total].size = size;
                entries[total].type = type;

                total++;
        }

        return total;
}

static int sfi_get_bank_size(void)
{
        struct sfi_table_simple *sb;
        struct sfi_mem_entry *mentry;
        int bank = 0;
        u32 i;

        sb = sfi_search_mmap();
        if (!sb)
                return 0;

        sfi_for_each_mentry(i, sb, mentry) {
                if (mentry->type != SFI_MEM_CONV)
                        continue;

                gd->bd->bi_dram[bank].start = mentry->phys_start;
                gd->bd->bi_dram[bank].size = mentry->pages << 12;
                bank++;
        }

        return bank;
}

static phys_size_t sfi_get_ram_size(void)
{
        struct sfi_table_simple *sb;
        struct sfi_mem_entry *mentry;
        phys_size_t ram = 0;
        u32 i;

        sb = sfi_search_mmap();
        if (!sb)
                return 0;

        sfi_for_each_mentry(i, sb, mentry) {
                if (mentry->type != SFI_MEM_CONV)
                        continue;

                ram += mentry->pages << 12;
        }

        debug("sfi: RAM size %llu\n", ram);
        return ram;
}

unsigned int install_e820_map(unsigned int max_entries,
                              struct e820_entry *entries)
{
        return sfi_setup_e820(max_entries, entries);
}

/*
 * This function looks for the highest region of memory lower than 2GB which
 * has enough space for U-Boot where U-Boot is aligned on a page boundary. It
 * overrides the default implementation found elsewhere which simply picks the
 * end of RAM, wherever that may be. The location of the stack, the relocation
 * address, and how far U-Boot is moved by relocation are set in the global
 * data structure.
 */
phys_size_t board_get_usable_ram_top(phys_size_t total_size)
{
        struct sfi_table_simple *sb;
        struct sfi_mem_entry *mentry;
        ulong dest_addr = 0;
        u32 i;

        sb = sfi_search_mmap();
        if (!sb)
                panic("No available memory found for relocation");

        sfi_for_each_mentry(i, sb, mentry) {
                unsigned long long start, end;

                if (mentry->type != SFI_MEM_CONV)
                        continue;

                start = mentry->phys_start;
                end = start + (mentry->pages << 12);

                /* Filter memory over 2GB. */
                if (end > 0x7fffffffULL)
                        end = 0x80000000ULL;
                /* Skip this region if it's too small. */
                if (end - start < total_size)
                        continue;

                /* Use this address if it's the largest so far. */
                if (end > dest_addr)
                        dest_addr = end;
        }

        return dest_addr;
}

int dram_init_banksize(void)
{
        sfi_get_bank_size();
        return 0;
}

int dram_init(void)
{
        gd->ram_size = sfi_get_ram_size();
        return 0;
}