/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _ASM_E820_TYPES_H
#define _ASM_E820_TYPES_H

#include <uapi/asm/bootparam.h>

/*
 * These are the E820 types known to the kernel:
 */
enum e820_type {
        E820_TYPE_RAM           = 1,
        E820_TYPE_RESERVED      = 2,
        E820_TYPE_ACPI          = 3,
        E820_TYPE_NVS           = 4,
        E820_TYPE_UNUSABLE      = 5,
        E820_TYPE_PMEM          = 7,

        /*
         * This is a non-standardized way to represent ADR or
         * NVDIMM regions that persist over a reboot.
         *
         * The kernel will ignore their special capabilities
         * unless the CONFIG_X86_PMEM_LEGACY=y option is set.
         *
         * ( Note that older platforms also used 6 for the same
         *   type of memory, but newer versions switched to 12 as
         *   6 was assigned differently. Some time they will learn... )
         */
        E820_TYPE_PRAM          = 12,

        /*
         * Special-purpose memory is indicated to the system via the
         * EFI_MEMORY_SP attribute. Define an e820 translation of this
         * memory type for the purpose of reserving this range and
         * marking it with the IORES_DESC_SOFT_RESERVED designation.
         */
        E820_TYPE_SOFT_RESERVED = 0xefffffff,
};

/*
 * A single E820 map entry, describing a memory range of [addr...addr+size-1],
 * of 'type' memory type:
 *
 * (We pack it because there can be thousands of them on large systems.)
 */
struct e820_entry {
        u64                     addr;
        u64                     size;
        enum e820_type          type;
} __attribute__((packed));

/*
 * The legacy E820 BIOS limits us to 128 (E820_MAX_ENTRIES_ZEROPAGE) nodes
 * due to the constrained space in the zeropage.
 *
 * On large systems we can easily have thousands of nodes with RAM,
 * which cannot be fit into so few entries - so we have a mechanism
 * to extend the e820 table size at build-time, via the E820_MAX_ENTRIES
 * define below.
 *
 * ( Those extra entries are enumerated via the EFI memory map, not
 *   via the legacy zeropage mechanism. )
 *
 * Size our internal memory map tables to have room for these additional
 * entries, based on a heuristic calculation: up to three entries per
 * NUMA node, plus E820_MAX_ENTRIES_ZEROPAGE for some extra space.
 *
 * This allows for bootstrap/firmware quirks such as possible duplicate
 * E820 entries that might need room in the same arrays, prior to the
 * call to e820__update_table() to remove duplicates.  The allowance
 * of three memory map entries per node is "enough" entries for
 * the initial hardware platform motivating this mechanism to make
 * use of additional EFI map entries.  Future platforms may want
 * to allow more than three entries per node or otherwise refine
 * this size.
 */

#include <linux/numa.h>

#define E820_MAX_ENTRIES        (E820_MAX_ENTRIES_ZEROPAGE + 3*MAX_NUMNODES)

/*
 * The whole array of E820 entries:
 */
struct e820_table {
        u32 nr_entries;
        struct e820_entry entries[E820_MAX_ENTRIES];
};

/*
 * Various well-known legacy memory ranges in physical memory:
 */
#define ISA_START_ADDRESS       0x000a0000
#define ISA_END_ADDRESS         0x00100000

#define BIOS_BEGIN              0x000a0000
#define BIOS_END                0x00100000

#define HIGH_MEMORY             0x00100000

#define BIOS_ROM_BASE           0xffe00000
#define BIOS_ROM_END            0xffffffff

#endif /* _ASM_E820_TYPES_H */