fit.c

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/* Taken from depthcharge: src/boot/fit.c */
/* SPDX-License-Identifier: GPL-2.0-or-later */
 
#include <assert.h>
#include <console/console.h>
#include <ctype.h>
#include <endian.h>
#include <bootmem.h>
#include <string.h>
#include <program_loading.h>
#include <memrange.h>
#include <fit.h>
#include <boardid.h>
#include <commonlib/stdlib.h>
#include <types.h>
 
static struct list_node image_nodes;
static struct list_node config_nodes;
static struct list_node compat_strings;
 
struct compat_string_entry {
        const char *compat_string;
        struct list_node list_node;
};
 
/* Convert string to lowercase and replace '_' and spaces with '-'. */
static char *clean_compat_string(char *str)
{
        for (size_t i = 0; i < strlen(str); i++) {
                str[i] = tolower(str[i]);
                if (str[i] == '_' || str[i] == ' ')
                        str[i] = '-';
        }
 
        return str;
}
 
static void fit_add_default_compat_strings(void)
{
        char compat_string[80] = {};
 
        if ((board_id() != UNDEFINED_STRAPPING_ID) &&
            (sku_id() != UNDEFINED_STRAPPING_ID)) {
                snprintf(compat_string, sizeof(compat_string),
                         "%s,%s-rev%u-sku%u", CONFIG_MAINBOARD_VENDOR,
                         CONFIG_MAINBOARD_PART_NUMBER, board_id(), sku_id());
 
                fit_add_compat_string(compat_string);
        }
 
        if (board_id() != UNDEFINED_STRAPPING_ID) {
                snprintf(compat_string, sizeof(compat_string), "%s,%s-rev%u",
                         CONFIG_MAINBOARD_VENDOR, CONFIG_MAINBOARD_PART_NUMBER,
                         board_id());
 
                fit_add_compat_string(compat_string);
        }
 
        if (sku_id() != UNDEFINED_STRAPPING_ID) {
                snprintf(compat_string, sizeof(compat_string), "%s,%s-sku%u",
                         CONFIG_MAINBOARD_VENDOR, CONFIG_MAINBOARD_PART_NUMBER,
                         sku_id());
 
                fit_add_compat_string(compat_string);
        }
 
        snprintf(compat_string, sizeof(compat_string), "%s,%s",
                 CONFIG_MAINBOARD_VENDOR, CONFIG_MAINBOARD_PART_NUMBER);
 
        fit_add_compat_string(compat_string);
}
 
static struct fit_image_node *find_image(const char *name)
{
        struct fit_image_node *image;
        list_for_each(image, image_nodes, list_node) {
                if (!strcmp(image->name, name))
                        return image;
        }
        printk(BIOS_ERR, "Cannot find image node %s!\n", name);
        return NULL;
}
 
static struct fit_image_node *find_image_with_overlays(const char *name,
        int bytes, struct list_node *prev)
{
        struct fit_image_node *base = find_image(name);
        if (!base)
                return NULL;
 
        int len = strnlen(name, bytes) + 1;
        bytes -= len;
        name += len;
        while (bytes > 0) {
                struct fit_overlay_chain *next = xzalloc(sizeof(*next));
                next->overlay = find_image(name);
                if (!next->overlay)
                        return NULL;
                list_insert_after(&next->list_node, prev);
                prev = &next->list_node;
                len = strnlen(name, bytes) + 1;
                bytes -= len;
                name += len;
        }
 
        return base;
}
 
static void image_node(struct device_tree_node *node)
{
        struct fit_image_node *image = xzalloc(sizeof(*image));
 
        image->compression = CBFS_COMPRESS_NONE;
        image->name = node->name;
 
        struct device_tree_property *prop;
        list_for_each(prop, node->properties, list_node) {
                if (!strcmp("data", prop->prop.name)) {
                        image->data = prop->prop.data;
                        image->size = prop->prop.size;
                } else if (!strcmp("compression", prop->prop.name)) {
                        if (!strcmp("none", prop->prop.data))
                                image->compression = CBFS_COMPRESS_NONE;
                        else if (!strcmp("lzma", prop->prop.data))
                                image->compression = CBFS_COMPRESS_LZMA;
                        else if (!strcmp("lz4", prop->prop.data))
                                image->compression = CBFS_COMPRESS_LZ4;
                        else
                                image->compression = -1;
                }
        }
 
        list_insert_after(&image->list_node, &image_nodes);
}
 
static void config_node(struct device_tree_node *node)
{
        struct fit_config_node *config = xzalloc(sizeof(*config));
        config->name = node->name;
 
        struct device_tree_property *prop;
        list_for_each(prop, node->properties, list_node) {
                if (!strcmp("kernel", prop->prop.name))
                        config->kernel = find_image(prop->prop.data);
                else if (!strcmp("fdt", prop->prop.name))
                        config->fdt = find_image_with_overlays(prop->prop.data,
                                prop->prop.size, &config->overlays);
                else if (!strcmp("ramdisk", prop->prop.name))
                        config->ramdisk = find_image(prop->prop.data);
                else if (!strcmp("compatible", prop->prop.name))
                        config->compat = prop->prop;
        }
 
        list_insert_after(&config->list_node, &config_nodes);
}
 
static void fit_unpack(struct device_tree *tree, const char **default_config)
{
        struct device_tree_node *child;
        struct device_tree_node *images = dt_find_node_by_path(tree, "/images",
                                                               NULL, NULL, 0);
        if (images)
                list_for_each(child, images->children, list_node)
                        image_node(child);
 
        struct device_tree_node *configs = dt_find_node_by_path(tree,
                "/configurations", NULL, NULL, 0);
        if (configs) {
                *default_config = dt_find_string_prop(configs, "default");
                list_for_each(child, configs->children, list_node)
                        config_node(child);
        }
}
 
static int fdt_find_compat(const void *blob, uint32_t start_offset,
                           struct fdt_property *prop)
{
        int offset = start_offset;
        int size;
 
        size = fdt_node_name(blob, offset, NULL);
        if (!size)
                return -1;
        offset += size;
 
        while ((size = fdt_next_property(blob, offset, prop))) {
                if (!strcmp("compatible", prop->name))
                        return 0;
 
                offset += size;
        }
 
        prop->name = NULL;
        return -1;
}
 
static int fit_check_compat(struct fdt_property *compat_prop,
                            const char *compat_name)
{
        int bytes = compat_prop->size;
        const char *compat_str = compat_prop->data;
 
        for (int pos = 0; bytes && compat_str[0]; pos++) {
                if (!strncmp(compat_str, compat_name, bytes))
                        return pos;
                int len = strlen(compat_str) + 1;
                compat_str += len;
                bytes -= len;
        }
        return -1;
}
 
void fit_update_chosen(struct device_tree *tree, const char *cmd_line)
{
        const char *path[] = { "chosen", NULL };
        struct device_tree_node *node;
        node = dt_find_node(tree->root, path, NULL, NULL, 1);
 
        dt_add_string_prop(node, "bootargs", cmd_line);
}
 
void fit_add_ramdisk(struct device_tree *tree, void *ramdisk_addr,
                     size_t ramdisk_size)
{
        const char *path[] = { "chosen", NULL };
        struct device_tree_node *node;
        node = dt_find_node(tree->root, path, NULL, NULL, 1);
 
        u64 start = (uintptr_t)ramdisk_addr;
        u64 end = start + ramdisk_size;
 
        dt_add_u64_prop(node, "linux,initrd-start", start);
        dt_add_u64_prop(node, "linux,initrd-end", end);
}
 
static void update_reserve_map(uint64_t start, uint64_t end,
                               struct device_tree *tree)
{
        struct device_tree_reserve_map_entry *entry = xzalloc(sizeof(*entry));
 
        entry->start = start;
        entry->size = end - start;
 
        list_insert_after(&entry->list_node, &tree->reserve_map);
}
 
struct entry_params {
        unsigned int addr_cells;
        unsigned int size_cells;
        void *data;
};
 
static uint64_t max_range(unsigned int size_cells)
{
        /*
         * Split up ranges who's sizes are too large to fit in #size-cells.
         * The largest value we can store isn't a power of two, so we'll round
         * down to make the math easier.
         */
        return 0x1ULL << (size_cells * 32 - 1);
}
 
static void update_mem_property(u64 start, u64 end, struct entry_params *params)
{
        u8 *data = (u8 *)params->data;
        u64 full_size = end - start;
        while (full_size) {
                const u64 max_size = max_range(params->size_cells);
                const u64 size = MIN(max_size, full_size);
 
                dt_write_int(data, start, params->addr_cells * sizeof(u32));
                data += params->addr_cells * sizeof(uint32_t);
                start += size;
 
                dt_write_int(data, size, params->size_cells * sizeof(u32));
                data += params->size_cells * sizeof(uint32_t);
                full_size -= size;
        }
        params->data = data;
}
 
struct mem_map {
        struct memranges mem;
        struct memranges reserved;
};
 
static bool walk_memory_table(const struct range_entry *r, void *arg)
{
        struct mem_map *arg_map = arg;
 
        /*
         * Kernel likes its available memory areas at least 1MB
         * aligned, let's trim the regions such that unaligned padding
         * is added to reserved memory.
         */
        if (range_entry_tag(r) == BM_MEM_RAM) {
                uint64_t new_start = ALIGN_UP(range_entry_base(r), 1 * MiB);
                uint64_t new_end = ALIGN_DOWN(range_entry_end(r), 1 * MiB);
 
                if (new_start != range_entry_base(r))
                        memranges_insert(&arg_map->reserved,
                                         range_entry_base(r),
                                         new_start - range_entry_base(r),
                                         BM_MEM_RESERVED);
 
                if (new_start != new_end)
                        memranges_insert(&arg_map->mem, new_start,
                                         new_end - new_start, BM_MEM_RAM);
 
                if (new_end != range_entry_end(r))
                        memranges_insert(&arg_map->reserved, new_end,
                                         range_entry_end(r) - new_end,
                                         BM_MEM_RESERVED);
        } else
                memranges_insert(&arg_map->reserved, range_entry_base(r),
                                 range_entry_size(r),
                                 BM_MEM_RESERVED);
 
        return true;
}
 
void fit_add_compat_string(const char *str)
{
        struct compat_string_entry *compat_node;
 
        compat_node = xzalloc(sizeof(*compat_node));
        compat_node->compat_string = strdup(str);
 
        clean_compat_string((char *)compat_node->compat_string);
 
        list_insert_after(&compat_node->list_node, &compat_strings);
}
 
void fit_update_memory(struct device_tree *tree)
{
        const struct range_entry *r;
        struct device_tree_node *node;
        u32 addr_cells = 1, size_cells = 1;
        struct mem_map map;
 
        printk(BIOS_INFO, "FIT: Updating devicetree memory entries\n");
 
        dt_read_cell_props(tree->root, &addr_cells, &size_cells);
 
        /*
         * First remove all existing device_type="memory" nodes, then add ours.
         */
        list_for_each(node, tree->root->children, list_node) {
                const char *devtype = dt_find_string_prop(node, "device_type");
                if (devtype && !strcmp(devtype, "memory"))
                        list_remove(&node->list_node);
        }
 
        node = xzalloc(sizeof(*node));
 
        node->name = "memory";
        list_insert_after(&node->list_node, &tree->root->children);
        dt_add_string_prop(node, "device_type", (char *)"memory");
 
        memranges_init_empty(&map.mem, NULL, 0);
        memranges_init_empty(&map.reserved, NULL, 0);
 
        bootmem_walk_os_mem(walk_memory_table, &map);
 
        /* CBMEM regions are both carved out and explicitly reserved. */
        memranges_each_entry(r, &map.reserved) {
                update_reserve_map(range_entry_base(r), range_entry_end(r),
                                   tree);
        }
 
        /*
         * Count the amount of 'reg' entries we need (account for size limits).
         */
        size_t count = 0;
        memranges_each_entry(r, &map.mem) {
                uint64_t size = range_entry_size(r);
                uint64_t max_size = max_range(size_cells);
                count += DIV_ROUND_UP(size, max_size);
        }
 
        /* Allocate the right amount of space and fill up the entries. */
        size_t length = count * (addr_cells + size_cells) * sizeof(u32);
 
        void *data = xzalloc(length);
 
        struct entry_params add_params = { addr_cells, size_cells, data };
        memranges_each_entry(r, &map.mem) {
                update_mem_property(range_entry_base(r), range_entry_end(r),
                                    &add_params);
        }
        assert(add_params.data - data == length);
 
        /* Assemble the final property and add it to the device tree. */
        dt_add_bin_prop(node, "reg", data, length);
 
        memranges_teardown(&map.mem);
        memranges_teardown(&map.reserved);
}
 
/*
 * Finds a compat string and updates the compat position and rank.
 * @param config The current config node to operate on
 * @return 0 if compat updated, -1 if this FDT cannot be used.
 */
static int fit_update_compat(struct fit_config_node *config)
{
        /* If there was no "compatible" property in config node, this is a
           legacy FIT image. Must extract compat prop from FDT itself. */
        if (!config->compat.name) {
                void *fdt_blob = config->fdt->data;
                const struct fdt_header *fdt_header = fdt_blob;
                uint32_t fdt_offset = be32_to_cpu(fdt_header->structure_offset);
 
                if (config->fdt->compression != CBFS_COMPRESS_NONE) {
                        printk(BIOS_ERR, "config %s has a compressed FDT without "
                               "external compatible property, skipping.\n",
                               config->name);
                        return -1;
                }
 
                /* FDT overlays are not supported in legacy FIT images. */
                if (config->overlays.next) {
                        printk(BIOS_ERR, "config %s has overlay but no compat!\n",
                               config->name);
                        return -1;
                }
 
                if (fdt_find_compat(fdt_blob, fdt_offset, &config->compat)) {
                        printk(BIOS_ERR, "Can't find compat string in FDT %s "
                               "for config %s, skipping.\n",
                               config->fdt->name, config->name);
                        return -1;
                }
        }
 
        config->compat_pos = -1;
        config->compat_rank = -1;
        size_t i = 0;
        struct compat_string_entry *compat_node;
        list_for_each(compat_node, compat_strings, list_node) {
                int pos = fit_check_compat(&config->compat,
                                           compat_node->compat_string);
                if (pos >= 0) {
                        config->compat_pos = pos;
                        config->compat_rank = i;
                        config->compat_string =
                                compat_node->compat_string;
                }
                i++;
        }
 
        return 0;
}
 
struct fit_config_node *fit_load(void *fit)
{
        struct fit_image_node *image;
        struct fit_config_node *config;
        struct compat_string_entry *compat_node;
        struct fit_overlay_chain *overlay_chain;
 
        printk(BIOS_DEBUG, "FIT: Loading FIT from %p\n", fit);
 
        struct device_tree *tree = fdt_unflatten(fit);
        if (!tree) {
                printk(BIOS_ERR, "Failed to unflatten FIT image!\n");
                return NULL;
        }
 
        const char *default_config_name = NULL;
        struct fit_config_node *default_config = NULL;
        struct fit_config_node *compat_config = NULL;
 
        fit_unpack(tree, &default_config_name);
 
        /* List the images we found. */
        list_for_each(image, image_nodes, list_node)
                printk(BIOS_DEBUG, "FIT: Image %s has %d bytes.\n", image->name,
                       image->size);
 
        fit_add_default_compat_strings();
 
        printk(BIOS_DEBUG, "FIT: Compat preference "
               "(lowest to highest priority) :");
 
        list_for_each(compat_node, compat_strings, list_node) {
                printk(BIOS_DEBUG, " %s", compat_node->compat_string);
        }
        printk(BIOS_DEBUG, "\n");
        /* Process and list the configs. */
        list_for_each(config, config_nodes, list_node) {
                if (!config->kernel) {
                        printk(BIOS_ERR, "config %s has no kernel, skipping.\n",
                               config->name);
                        continue;
                }
                if (!config->fdt) {
                        printk(BIOS_ERR, "config %s has no FDT, skipping.\n",
                               config->name);
                        continue;
                }
 
                if (config->ramdisk &&
                    config->ramdisk->compression < 0) {
                        printk(BIOS_WARNING, "Ramdisk is compressed with "
                               "an unsupported algorithm, discarding config %s."
                               "\n", config->name);
                        continue;
                }
 
                if (fit_update_compat(config))
                        continue;
 
                printk(BIOS_DEBUG, "FIT: config %s", config->name);
                if (default_config_name &&
                    !strcmp(config->name, default_config_name)) {
                        printk(BIOS_DEBUG, " (default)");
                        default_config = config;
                }
                printk(BIOS_DEBUG, ", kernel %s", config->kernel->name);
                printk(BIOS_DEBUG, ", fdt %s", config->fdt->name);
                list_for_each(overlay_chain, config->overlays, list_node)
                        printk(BIOS_DEBUG, " %s", overlay_chain->overlay->name);
                if (config->ramdisk)
                        printk(BIOS_DEBUG, ", ramdisk %s",
                               config->ramdisk->name);
                if (config->compat.name) {
                        printk(BIOS_DEBUG, ", compat");
                        int bytes = config->compat.size;
                        const char *compat_str = config->compat.data;
                        for (int pos = 0; bytes && compat_str[0]; pos++) {
                                printk(BIOS_DEBUG, " %s", compat_str);
                                if (pos == config->compat_pos)
                                        printk(BIOS_DEBUG, " (match)");
                                int len = strlen(compat_str) + 1;
                                compat_str += len;
                                bytes -= len;
                        }
 
                        if (config->compat_rank >= 0 && (!compat_config ||
                            config->compat_rank > compat_config->compat_rank))
                                compat_config = config;
                }
                printk(BIOS_DEBUG, "\n");
        }
 
        struct fit_config_node *to_boot = NULL;
        if (compat_config) {
                to_boot = compat_config;
                printk(BIOS_INFO, "FIT: Choosing best match %s for compat "
                       "%s.\n", to_boot->name, to_boot->compat_string);
        } else if (default_config) {
                to_boot = default_config;
                printk(BIOS_INFO, "FIT: No match, choosing default %s.\n",
                       to_boot->name);
        } else {
                printk(BIOS_ERR, "FIT: No compatible or default configs. "
                       "Giving up.\n");
                return NULL;
        }
 
        return to_boot;
}