// 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/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/screen_info.h>

#include <asm/efi.h>

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;
}

static __initdata unsigned long screen_info_table = EFI_INVALID_TABLE_ADDR;

static const efi_config_table_type_t arch_tables[] __initconst = {
        {LINUX_EFI_ARM_SCREEN_INFO_TABLE_GUID, NULL, &screen_info_table},
        {NULL_GUID, NULL, NULL}
};

static void __init init_screen_info(void)
{
        struct screen_info *si;

        if (screen_info_table != EFI_INVALID_TABLE_ADDR) {
                si = early_memremap_ro(screen_info_table, sizeof(*si));
                if (!si) {
                        pr_err("Could not map screen_info config table\n");
                        return;
                }
                screen_info = *si;
                early_memunmap(si, sizeof(*si));

                /* dummycon on ARM needs non-zero values for columns/lines */
                screen_info.orig_video_cols = 80;
                screen_info.orig_video_lines = 25;
        }

        if (screen_info.orig_video_isVGA == VIDEO_TYPE_EFI &&
            memblock_is_map_memory(screen_info.lfb_base))
                memblock_mark_nomap(screen_info.lfb_base, screen_info.lfb_size);
}

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, 2);
        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,
                                         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:
                /*
                 * Special purpose memory is 'soft reserved', which means it
                 * is set aside initially, but can be hotplugged back in or
                 * be assigned to the dax driver after boot.
                 */
                if (efi_soft_reserve_enabled() &&
                    (md->attribute & EFI_MEMORY_SP))
                        return false;

                /*
                 * 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: if there are any at this
         * point, they originate from memory nodes in the DT, and UEFI
         * uses its own memory map instead.
         */
        memblock_dump_all();
        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)) {
                        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();
        efi_esrt_init();

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

        init_screen_info();

        /* ARM does not permit early mappings to persist across paging_init() */
        if (IS_ENABLED(CONFIG_ARM))
                efi_memmap_unmap();
}

static bool efifb_overlaps_pci_range(const struct of_pci_range *range)
{
        u64 fb_base = screen_info.lfb_base;

        if (screen_info.capabilities & VIDEO_CAPABILITY_64BIT_BASE)
                fb_base |= (u64)(unsigned long)screen_info.ext_lfb_base << 32;

        return fb_base >= range->cpu_addr &&
               fb_base < (range->cpu_addr + range->size);
}

static struct device_node *find_pci_overlap_node(void)
{
        struct device_node *np;

        for_each_node_by_type(np, "pci") {
                struct of_pci_range_parser parser;
                struct of_pci_range range;
                int err;

                err = of_pci_range_parser_init(&parser, np);
                if (err) {
                        pr_warn("of_pci_range_parser_init() failed: %d\n", err);
                        continue;
                }

                for_each_of_pci_range(&parser, &range)
                        if (efifb_overlaps_pci_range(&range))
                                return np;
        }
        return NULL;
}

/*
 * If the efifb framebuffer is backed by a PCI graphics controller, we have
 * to ensure that this relation is expressed using a device link when
 * running in DT mode, or the probe order may be reversed, resulting in a
 * resource reservation conflict on the memory window that the efifb
 * framebuffer steals from the PCIe host bridge.
 */
static int efifb_add_links(const struct fwnode_handle *fwnode,
                           struct device *dev)
{
        struct device_node *sup_np;
        struct device *sup_dev;

        sup_np = find_pci_overlap_node();

        /*
         * If there's no PCI graphics controller backing the efifb, we are
         * done here.
         */
        if (!sup_np)
                return 0;

        sup_dev = get_dev_from_fwnode(&sup_np->fwnode);
        of_node_put(sup_np);

        /*
         * Return -ENODEV if the PCI graphics controller device hasn't been
         * registered yet.  This ensures that efifb isn't allowed to probe
         * and this function is retried again when new devices are
         * registered.
         */
        if (!sup_dev)
                return -ENODEV;

        /*
         * If this fails, retrying this function at a later point won't
         * change anything. So, don't return an error after this.
         */
        if (!device_link_add(dev, sup_dev, fw_devlink_get_flags()))
                dev_warn(dev, "device_link_add() failed\n");

        put_device(sup_dev);

        return 0;
}

static const struct fwnode_operations efifb_fwnode_ops = {
        .add_links = efifb_add_links,
};

static struct fwnode_handle efifb_fwnode = {
        .ops = &efifb_fwnode_ops,
};

static int __init register_gop_device(void)
{
        struct platform_device *pd;
        int err;

        if (screen_info.orig_video_isVGA != VIDEO_TYPE_EFI)
                return 0;

        pd = platform_device_alloc("efi-framebuffer", 0);
        if (!pd)
                return -ENOMEM;

        if (IS_ENABLED(CONFIG_PCI))
                pd->dev.fwnode = &efifb_fwnode;

        err = platform_device_add_data(pd, &screen_info, sizeof(screen_info));
        if (err)
                return err;

        return platform_device_add(pd);
}
subsys_initcall(register_gop_device);