// SPDX-License-Identifier: GPL-2.0
/*
 * Extensible Firmware Interface
 *
 * Based on Extensible Firmware Interface Specification version 2.4
 *
 * Copyright (C) 2013 - 2015 Linaro Ltd.
 */

#define pr_fmt(fmt)     "efi: " fmt

#include <linux/efi.h>
#include <linux/fwnode.h>
#include <linux/init.h>
#include <linux/kexec_handover.h>
#include <linux/memblock.h>
#include <linux/mm_types.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_fdt.h>
#include <linux/platform_device.h>
#include <linux/sysfb.h>

#include <asm/efi.h>

unsigned long __initdata primary_display_table = EFI_INVALID_TABLE_ADDR;

static int __init is_memory(efi_memory_desc_t *md)
{
        if (md->attribute & (EFI_MEMORY_WB|EFI_MEMORY_WT|EFI_MEMORY_WC))
                return 1;
        return 0;
}

/*
 * Translate a EFI virtual address into a physical address: this is necessary,
 * as some data members of the EFI system table are virtually remapped after
 * SetVirtualAddressMap() has been called.
 */
static phys_addr_t __init efi_to_phys(unsigned long addr)
{
        efi_memory_desc_t *md;

        for_each_efi_memory_desc(md) {
                if (!(md->attribute & EFI_MEMORY_RUNTIME))
                        continue;
                if (md->virt_addr == 0)
                        /* no virtual mapping has been installed by the stub */
                        break;
                if (md->virt_addr <= addr &&
                    (addr - md->virt_addr) < (md->num_pages << EFI_PAGE_SHIFT))
                        return md->phys_addr + addr - md->virt_addr;
        }
        return addr;
}

extern __weak const efi_config_table_type_t efi_arch_tables[];

/*
 * x86 defines its own instance of sysfb_primary_display and uses
 * it even without EFI, everything else can get them from here.
 */
#if !defined(CONFIG_X86) && (defined(CONFIG_SYSFB) || defined(CONFIG_EFI_EARLYCON)) || defined(CONFIG_FIRMWARE_EDID)
struct sysfb_display_info sysfb_primary_display __section(".data");
EXPORT_SYMBOL_GPL(sysfb_primary_display);
#endif

static void __init init_primary_display(void)
{
        struct sysfb_display_info *dpy;

        if (primary_display_table != EFI_INVALID_TABLE_ADDR) {
                dpy = early_memremap(primary_display_table, sizeof(*dpy));
                if (!dpy) {
                        pr_err("Could not map primary_display config table\n");
                        return;
                }
                sysfb_primary_display = *dpy;
                memset(dpy, 0, sizeof(*dpy));
                early_memunmap(dpy, sizeof(*dpy));

                if (memblock_is_map_memory(sysfb_primary_display.screen.lfb_base))
                        memblock_mark_nomap(sysfb_primary_display.screen.lfb_base,
                                            sysfb_primary_display.screen.lfb_size);

                if (IS_ENABLED(CONFIG_EFI_EARLYCON))
                        efi_earlycon_reprobe();
        }
}

static int __init uefi_init(u64 efi_system_table)
{
        efi_config_table_t *config_tables;
        efi_system_table_t *systab;
        size_t table_size;
        int retval;

        systab = early_memremap_ro(efi_system_table, sizeof(efi_system_table_t));
        if (systab == NULL) {
                pr_warn("Unable to map EFI system table.\n");
                return -ENOMEM;
        }

        set_bit(EFI_BOOT, &efi.flags);
        if (IS_ENABLED(CONFIG_64BIT))
                set_bit(EFI_64BIT, &efi.flags);

        retval = efi_systab_check_header(&systab->hdr);
        if (retval)
                goto out;

        efi.runtime = systab->runtime;
        efi.runtime_version = systab->hdr.revision;

        efi_systab_report_header(&systab->hdr, efi_to_phys(systab->fw_vendor));

        table_size = sizeof(efi_config_table_t) * systab->nr_tables;
        config_tables = early_memremap_ro(efi_to_phys(systab->tables),
                                          table_size);
        if (config_tables == NULL) {
                pr_warn("Unable to map EFI config table array.\n");
                retval = -ENOMEM;
                goto out;
        }
        retval = efi_config_parse_tables(config_tables, systab->nr_tables,
                                         efi_arch_tables);

        early_memunmap(config_tables, table_size);
out:
        early_memunmap(systab, sizeof(efi_system_table_t));
        return retval;
}

/*
 * Return true for regions that can be used as System RAM.
 */
static __init int is_usable_memory(efi_memory_desc_t *md)
{
        switch (md->type) {
        case EFI_LOADER_CODE:
        case EFI_LOADER_DATA:
        case EFI_ACPI_RECLAIM_MEMORY:
        case EFI_BOOT_SERVICES_CODE:
        case EFI_BOOT_SERVICES_DATA:
        case EFI_CONVENTIONAL_MEMORY:
        case EFI_PERSISTENT_MEMORY:
                /*
                 * According to the spec, these regions are no longer reserved
                 * after calling ExitBootServices(). However, we can only use
                 * them as System RAM if they can be mapped writeback cacheable.
                 */
                return (md->attribute & EFI_MEMORY_WB);
        default:
                break;
        }
        return false;
}

static __init void reserve_regions(void)
{
        efi_memory_desc_t *md;
        u64 paddr, npages, size;

        if (efi_enabled(EFI_DBG))
                pr_info("Processing EFI memory map:\n");

        /*
         * Discard memblocks discovered so far except for KHO scratch
         * regions. Most memblocks at this point originate from memory nodes
         * in the DT and UEFI uses its own memory map instead. However, if
         * KHO is enabled, scratch regions, which are good known memory
         * must be preserved.
         */
        memblock_dump_all();

        if (is_kho_boot()) {
                struct memblock_region *r;

                /* Remove all non-KHO regions */
                for_each_mem_region(r) {
                        if (!memblock_is_kho_scratch(r)) {
                                memblock_remove(r->base, r->size);
                                r--;
                        }
                }
        } else {
                /*
                 * KHO is disabled. Discard memblocks discovered so far:
                 * if there are any at this point, they originate from memory
                 * nodes in the DT, and UEFI uses its own memory map instead.
                 */
                memblock_remove(0, PHYS_ADDR_MAX);
        }

        for_each_efi_memory_desc(md) {
                paddr = md->phys_addr;
                npages = md->num_pages;

                if (efi_enabled(EFI_DBG)) {
                        char buf[64];

                        pr_info("  0x%012llx-0x%012llx %s\n",
                                paddr, paddr + (npages << EFI_PAGE_SHIFT) - 1,
                                efi_md_typeattr_format(buf, sizeof(buf), md));
                }

                memrange_efi_to_native(&paddr, &npages);
                size = npages << PAGE_SHIFT;

                if (is_memory(md)) {
                        /*
                         * Special purpose memory is 'soft reserved', which
                         * means it is set aside initially. Don't add a memblock
                         * for it now so that it can be hotplugged back in or
                         * be assigned to the dax driver after boot.
                         */
                        if (efi_soft_reserve_enabled() &&
                            (md->attribute & EFI_MEMORY_SP))
                                continue;

                        early_init_dt_add_memory_arch(paddr, size);

                        if (!is_usable_memory(md))
                                memblock_mark_nomap(paddr, size);

                        /* keep ACPI reclaim memory intact for kexec etc. */
                        if (md->type == EFI_ACPI_RECLAIM_MEMORY)
                                memblock_reserve(paddr, size);
                }
        }
}

void __init efi_init(void)
{
        struct efi_memory_map_data data;
        u64 efi_system_table;

        /* Grab UEFI information placed in FDT by stub */
        efi_system_table = efi_get_fdt_params(&data);
        if (!efi_system_table)
                return;

        if (efi_memmap_init_early(&data) < 0) {
                /*
                * If we are booting via UEFI, the UEFI memory map is the only
                * description of memory we have, so there is little point in
                * proceeding if we cannot access it.
                */
                panic("Unable to map EFI memory map.\n");
        }

        WARN(efi.memmap.desc_version != 1,
             "Unexpected EFI_MEMORY_DESCRIPTOR version %ld",
              efi.memmap.desc_version);

        if (uefi_init(efi_system_table) < 0) {
                efi_memmap_unmap();
                return;
        }

        reserve_regions();
        /*
         * For memblock manipulation, the cap should come after the memblock_add().
         * And now, memblock is fully populated, it is time to do capping.
         */
        early_init_dt_check_for_usable_mem_range();
        efi_find_mirror();
        efi_esrt_init();
        efi_mokvar_table_init();

        memblock_reserve(data.phys_map & PAGE_MASK,
                         PAGE_ALIGN(data.size + (data.phys_map & ~PAGE_MASK)));

        if (IS_ENABLED(CONFIG_X86) ||
            IS_ENABLED(CONFIG_SYSFB) ||
            IS_ENABLED(CONFIG_EFI_EARLYCON))
                init_primary_display();
}