// SPDX-License-Identifier: GPL-2.0+
/*
 * (C) Copyright 2007
 * Gerald Van Baren, Custom IDEAS, vanbaren@cideas.com
 * Based on code written by:
 *   Pantelis Antoniou <pantelis.antoniou@gmail.com> and
 *   Matthew McClintock <msm@freescale.com>
 */

#include <common.h>
#include <command.h>
#include <env.h>
#include <image.h>
#include <linux/ctype.h>
#include <linux/types.h>
#include <asm/global_data.h>
#include <linux/libfdt.h>
#include <fdt_support.h>
#include <mapmem.h>
#include <asm/io.h>

#define MAX_LEVEL       32              /* how deeply nested we will go */
#define SCRATCHPAD      1024            /* bytes of scratchpad memory */

/*
 * Global data (for the gd->bd)
 */
DECLARE_GLOBAL_DATA_PTR;

static int fdt_parse_prop(char *const*newval, int count, char *data, int *len);
static int fdt_print(const char *pathp, char *prop, int depth);
static int is_printable_string(const void *data, int len);

/*
 * The working_fdt points to our working flattened device tree.
 */
struct fdt_header *working_fdt;

void set_working_fdt_addr(ulong addr)
{
        void *buf;

        buf = map_sysmem(addr, 0);
        working_fdt = buf;
        env_set_hex("fdtaddr", addr);
}

/*
 * Get a value from the fdt and format it to be set in the environment
 */
static int fdt_value_env_set(const void *nodep, int len, const char *var)
{
        if (is_printable_string(nodep, len))
                env_set(var, (void *)nodep);
        else if (len == 4) {
                char buf[11];

                sprintf(buf, "0x%08X", fdt32_to_cpu(*(fdt32_t *)nodep));
                env_set(var, buf);
        } else if (len%4 == 0 && len <= 20) {
                /* Needed to print things like sha1 hashes. */
                char buf[41];
                int i;

                for (i = 0; i < len; i += sizeof(unsigned int))
                        sprintf(buf + (i * 2), "%08x",
                                *(unsigned int *)(nodep + i));
                env_set(var, buf);
        } else {
                printf("error: unprintable value\n");
                return 1;
        }
        return 0;
}

static const char * const fdt_member_table[] = {
        "magic",
        "totalsize",
        "off_dt_struct",
        "off_dt_strings",
        "off_mem_rsvmap",
        "version",
        "last_comp_version",
        "boot_cpuid_phys",
        "size_dt_strings",
        "size_dt_struct",
};

static int fdt_get_header_value(int argc, char *const argv[])
{
        fdt32_t *fdtp = (fdt32_t *)working_fdt;
        ulong val;
        int i;

        if (argv[2][0] != 'g')
                return CMD_RET_FAILURE;

        for (i = 0; i < ARRAY_SIZE(fdt_member_table); i++) {
                if (strcmp(fdt_member_table[i], argv[4]))
                        continue;

                val = fdt32_to_cpu(fdtp[i]);
                env_set_hex(argv[3], val);
                return CMD_RET_SUCCESS;
        }

        return CMD_RET_FAILURE;
}

/*
 * Flattened Device Tree command, see the help for parameter definitions.
 */
static int do_fdt(struct cmd_tbl *cmdtp, int flag, int argc, char *const argv[])
{
        if (argc < 2)
                return CMD_RET_USAGE;

        /* fdt addr: Set the address of the fdt */
        if (strncmp(argv[1], "ad", 2) == 0) {
                unsigned long addr;
                int control = 0;
                struct fdt_header *blob;

                /* Set the address [and length] of the fdt */
                argc -= 2;
                argv += 2;
                if (argc && !strcmp(*argv, "-c")) {
                        control = 1;
                        argc--;
                        argv++;
                }
                if (argc == 0) {
                        if (control)
                                blob = (struct fdt_header *)gd->fdt_blob;
                        else
                                blob = working_fdt;
                        if (!blob || !fdt_valid(&blob))
                                return 1;
                        printf("%s fdt: %08lx\n",
                               control ? "Control" : "Working",
                               control ? (ulong)map_to_sysmem(blob) :
                               env_get_hex("fdtaddr", 0));
                        return 0;
                }

                addr = hextoul(argv[0], NULL);
                blob = map_sysmem(addr, 0);
                if (!fdt_valid(&blob))
                        return 1;
                if (control)
                        gd->fdt_blob = blob;
                else
                        set_working_fdt_addr(addr);

                if (argc >= 2) {
                        int  len;
                        int  err;

                        /* Optional new length */
                        len = hextoul(argv[1], NULL);
                        if (len < fdt_totalsize(blob)) {
                                printf("New length %d < existing length %d, ignoring\n",
                                       len, fdt_totalsize(blob));
                        } else {
                                /* Open in place with a new length */
                                err = fdt_open_into(blob, blob, len);
                                if (err != 0) {
                                        printf("libfdt fdt_open_into(): %s\n",
                                               fdt_strerror(err));
                                }
                        }
                }

                return CMD_RET_SUCCESS;
        }

        if (!working_fdt) {
                puts("No FDT memory address configured. Please configure\n"
                     "the FDT address via \"fdt addr <address>\" command.\n"
                     "Aborting!\n");
                return CMD_RET_FAILURE;
        }

        /*
         * Move the working_fdt
         */
        if (strncmp(argv[1], "mo", 2) == 0) {
                struct fdt_header *newaddr;
                int  len;
                int  err;

                if (argc < 4)
                        return CMD_RET_USAGE;

                /*
                 * Set the address and length of the fdt.
                 */
                working_fdt = (struct fdt_header *)hextoul(argv[2], NULL);
                if (!fdt_valid(&working_fdt))
                        return 1;

                newaddr = (struct fdt_header *)hextoul(argv[3], NULL);

                /*
                 * If the user specifies a length, use that.  Otherwise use the
                 * current length.
                 */
                if (argc <= 4) {
                        len = fdt_totalsize(working_fdt);
                } else {
                        len = hextoul(argv[4], NULL);
                        if (len < fdt_totalsize(working_fdt)) {
                                printf ("New length 0x%X < existing length "
                                        "0x%X, aborting.\n",
                                        len, fdt_totalsize(working_fdt));
                                return 1;
                        }
                }

                /*
                 * Copy to the new location.
                 */
                err = fdt_open_into(working_fdt, newaddr, len);
                if (err != 0) {
                        printf ("libfdt fdt_open_into(): %s\n",
                                fdt_strerror(err));
                        return 1;
                }
                set_working_fdt_addr((ulong)newaddr);
#ifdef CONFIG_OF_SYSTEM_SETUP
        /* Call the board-specific fixup routine */
        } else if (strncmp(argv[1], "sys", 3) == 0) {
                int err = ft_system_setup(working_fdt, gd->bd);

                if (err) {
                        printf("Failed to add system information to FDT: %s\n",
                               fdt_strerror(err));
                        return CMD_RET_FAILURE;
                }
#endif
        /*
         * Make a new node
         */
        } else if (strncmp(argv[1], "mk", 2) == 0) {
                char *pathp;            /* path */
                char *nodep;            /* new node to add */
                int  nodeoffset;        /* node offset from libfdt */
                int  err;

                /*
                 * Parameters: Node path, new node to be appended to the path.
                 */
                if (argc < 4)
                        return CMD_RET_USAGE;

                pathp = argv[2];
                nodep = argv[3];

                nodeoffset = fdt_path_offset (working_fdt, pathp);
                if (nodeoffset < 0) {
                        /*
                         * Not found or something else bad happened.
                         */
                        printf ("libfdt fdt_path_offset() returned %s\n",
                                fdt_strerror(nodeoffset));
                        return 1;
                }
                err = fdt_add_subnode(working_fdt, nodeoffset, nodep);
                if (err < 0) {
                        printf ("libfdt fdt_add_subnode(): %s\n",
                                fdt_strerror(err));
                        return 1;
                }

        /*
         * Set the value of a property in the working_fdt.
         */
        } else if (strncmp(argv[1], "se", 2) == 0) {
                char *pathp;            /* path */
                char *prop;             /* property */
                int  nodeoffset;        /* node offset from libfdt */
                static char data[SCRATCHPAD] __aligned(4);/* property storage */
                const void *ptmp;
                int  len;               /* new length of the property */
                int  ret;               /* return value */

                /*
                 * Parameters: Node path, property, optional value.
                 */
                if (argc < 4)
                        return CMD_RET_USAGE;

                pathp  = argv[2];
                prop   = argv[3];

                nodeoffset = fdt_path_offset (working_fdt, pathp);
                if (nodeoffset < 0) {
                        /*
                         * Not found or something else bad happened.
                         */
                        printf ("libfdt fdt_path_offset() returned %s\n",
                                fdt_strerror(nodeoffset));
                        return 1;
                }

                if (argc == 4) {
                        len = 0;
                } else {
                        ptmp = fdt_getprop(working_fdt, nodeoffset, prop, &len);
                        if (len > SCRATCHPAD) {
                                printf("prop (%d) doesn't fit in scratchpad!\n",
                                       len);
                                return 1;
                        }
                        if (ptmp != NULL)
                                memcpy(data, ptmp, len);

                        ret = fdt_parse_prop(&argv[4], argc - 4, data, &len);
                        if (ret != 0)
                                return ret;
                }

                ret = fdt_setprop(working_fdt, nodeoffset, prop, data, len);
                if (ret < 0) {
                        printf ("libfdt fdt_setprop(): %s\n", fdt_strerror(ret));
                        return 1;
                }

        /********************************************************************
         * Get the value of a property in the working_fdt.
         ********************************************************************/
        } else if (argv[1][0] == 'g') {
                char *subcmd;           /* sub-command */
                char *pathp;            /* path */
                char *prop;             /* property */
                char *var;              /* variable to store result */
                int  nodeoffset;        /* node offset from libfdt */
                const void *nodep;      /* property node pointer */
                int  len = 0;           /* new length of the property */

                /*
                 * Parameters: Node path, property, optional value.
                 */
                if (argc < 5)
                        return CMD_RET_USAGE;

                subcmd = argv[2];

                if (argc < 6 && subcmd[0] != 's')
                        return CMD_RET_USAGE;

                var    = argv[3];
                pathp  = argv[4];
                prop   = argv[5];

                nodeoffset = fdt_path_offset(working_fdt, pathp);
                if (nodeoffset < 0) {
                        /*
                         * Not found or something else bad happened.
                         */
                        printf("libfdt fdt_path_offset() returned %s\n",
                                fdt_strerror(nodeoffset));
                        return 1;
                }

                if (subcmd[0] == 'n' || (subcmd[0] == 's' && argc == 5)) {
                        int req_index = -1;
                        int startDepth = fdt_node_depth(
                                working_fdt, nodeoffset);
                        int curDepth = startDepth;
                        int cur_index = -1;
                        int nextNodeOffset = fdt_next_node(
                                working_fdt, nodeoffset, &curDepth);

                        if (subcmd[0] == 'n')
                                req_index = hextoul(argv[5], NULL);

                        while (curDepth > startDepth) {
                                if (curDepth == startDepth + 1)
                                        cur_index++;
                                if (subcmd[0] == 'n' &&
                                    cur_index == req_index) {
                                        const char *node_name;

                                        node_name = fdt_get_name(working_fdt,
                                                                 nextNodeOffset,
                                                                 NULL);
                                        env_set(var, node_name);
                                        return 0;
                                }
                                nextNodeOffset = fdt_next_node(
                                        working_fdt, nextNodeOffset, &curDepth);
                                if (nextNodeOffset < 0)
                                        break;
                        }
                        if (subcmd[0] == 's') {
                                /* get the num nodes at this level */
                                env_set_ulong(var, cur_index + 1);
                        } else {
                                /* node index not found */
                                printf("libfdt node not found\n");
                                return 1;
                        }
                } else {
                        nodep = fdt_getprop(
                                working_fdt, nodeoffset, prop, &len);
                        if (len == 0) {
                                /* no property value */
                                env_set(var, "");
                                return 0;
                        } else if (nodep && len > 0) {
                                if (subcmd[0] == 'v') {
                                        int ret;

                                        ret = fdt_value_env_set(nodep, len,
                                                                var);
                                        if (ret != 0)
                                                return ret;
                                } else if (subcmd[0] == 'a') {
                                        /* Get address */
                                        char buf[11];

                                        sprintf(buf, "0x%p", nodep);
                                        env_set(var, buf);
                                } else if (subcmd[0] == 's') {
                                        /* Get size */
                                        char buf[11];

                                        sprintf(buf, "0x%08X", len);
                                        env_set(var, buf);
                                } else
                                        return CMD_RET_USAGE;
                                return 0;
                        } else {
                                printf("libfdt fdt_getprop(): %s\n",
                                        fdt_strerror(len));
                                return 1;
                        }
                }

        /*
         * Print (recursive) / List (single level)
         */
        } else if ((argv[1][0] == 'p') || (argv[1][0] == 'l')) {
                int depth = MAX_LEVEL;  /* how deep to print */
                char *pathp;            /* path */
                char *prop;             /* property */
                int  ret;               /* return value */
                static char root[2] = "/";

                /*
                 * list is an alias for print, but limited to 1 level
                 */
                if (argv[1][0] == 'l') {
                        depth = 1;
                }

                /*
                 * Get the starting path.  The root node is an oddball,
                 * the offset is zero and has no name.
                 */
                if (argc == 2)
                        pathp = root;
                else
                        pathp = argv[2];
                if (argc > 3)
                        prop = argv[3];
                else
                        prop = NULL;

                ret = fdt_print(pathp, prop, depth);
                if (ret != 0)
                        return ret;

        /*
         * Remove a property/node
         */
        } else if (strncmp(argv[1], "rm", 2) == 0) {
                int  nodeoffset;        /* node offset from libfdt */
                int  err;

                /*
                 * Get the path.  The root node is an oddball, the offset
                 * is zero and has no name.
                 */
                nodeoffset = fdt_path_offset (working_fdt, argv[2]);
                if (nodeoffset < 0) {
                        /*
                         * Not found or something else bad happened.
                         */
                        printf ("libfdt fdt_path_offset() returned %s\n",
                                fdt_strerror(nodeoffset));
                        return 1;
                }
                /*
                 * Do the delete.  A fourth parameter means delete a property,
                 * otherwise delete the node.
                 */
                if (argc > 3) {
                        err = fdt_delprop(working_fdt, nodeoffset, argv[3]);
                        if (err < 0) {
                                printf("libfdt fdt_delprop():  %s\n",
                                        fdt_strerror(err));
                                return err;
                        }
                } else {
                        err = fdt_del_node(working_fdt, nodeoffset);
                        if (err < 0) {
                                printf("libfdt fdt_del_node():  %s\n",
                                        fdt_strerror(err));
                                return err;
                        }
                }

        /*
         * Display header info
         */
        } else if (argv[1][0] == 'h') {
                if (argc == 5)
                        return fdt_get_header_value(argc, argv);

                u32 version = fdt_version(working_fdt);
                printf("magic:\t\t\t0x%x\n", fdt_magic(working_fdt));
                printf("totalsize:\t\t0x%x (%d)\n", fdt_totalsize(working_fdt),
                       fdt_totalsize(working_fdt));
                printf("off_dt_struct:\t\t0x%x\n",
                       fdt_off_dt_struct(working_fdt));
                printf("off_dt_strings:\t\t0x%x\n",
                       fdt_off_dt_strings(working_fdt));
                printf("off_mem_rsvmap:\t\t0x%x\n",
                       fdt_off_mem_rsvmap(working_fdt));
                printf("version:\t\t%d\n", version);
                printf("last_comp_version:\t%d\n",
                       fdt_last_comp_version(working_fdt));
                if (version >= 2)
                        printf("boot_cpuid_phys:\t0x%x\n",
                                fdt_boot_cpuid_phys(working_fdt));
                if (version >= 3)
                        printf("size_dt_strings:\t0x%x\n",
                                fdt_size_dt_strings(working_fdt));
                if (version >= 17)
                        printf("size_dt_struct:\t\t0x%x\n",
                                fdt_size_dt_struct(working_fdt));
                printf("number mem_rsv:\t\t0x%x\n",
                       fdt_num_mem_rsv(working_fdt));
                printf("\n");

        /*
         * Set boot cpu id
         */
        } else if (strncmp(argv[1], "boo", 3) == 0) {
                unsigned long tmp = hextoul(argv[2], NULL);
                fdt_set_boot_cpuid_phys(working_fdt, tmp);

        /*
         * memory command
         */
        } else if (strncmp(argv[1], "me", 2) == 0) {
                uint64_t addr, size;
                int err;
                addr = simple_strtoull(argv[2], NULL, 16);
                size = simple_strtoull(argv[3], NULL, 16);
                err = fdt_fixup_memory(working_fdt, addr, size);
                if (err < 0)
                        return err;

        /*
         * mem reserve commands
         */
        } else if (strncmp(argv[1], "rs", 2) == 0) {
                if (argv[2][0] == 'p') {
                        uint64_t addr, size;
                        int total = fdt_num_mem_rsv(working_fdt);
                        int j, err;
                        printf("index\t\t   start\t\t    size\n");
                        printf("-------------------------------"
                                "-----------------\n");
                        for (j = 0; j < total; j++) {
                                err = fdt_get_mem_rsv(working_fdt, j, &addr, &size);
                                if (err < 0) {
                                        printf("libfdt fdt_get_mem_rsv():  %s\n",
                                                        fdt_strerror(err));
                                        return err;
                                }
                                printf("    %x\t%08x%08x\t%08x%08x\n", j,
                                        (u32)(addr >> 32),
                                        (u32)(addr & 0xffffffff),
                                        (u32)(size >> 32),
                                        (u32)(size & 0xffffffff));
                        }
                } else if (argv[2][0] == 'a') {
                        uint64_t addr, size;
                        int err;
                        addr = simple_strtoull(argv[3], NULL, 16);
                        size = simple_strtoull(argv[4], NULL, 16);
                        err = fdt_add_mem_rsv(working_fdt, addr, size);

                        if (err < 0) {
                                printf("libfdt fdt_add_mem_rsv():  %s\n",
                                        fdt_strerror(err));
                                return err;
                        }
                } else if (argv[2][0] == 'd') {
                        unsigned long idx = hextoul(argv[3], NULL);
                        int err = fdt_del_mem_rsv(working_fdt, idx);

                        if (err < 0) {
                                printf("libfdt fdt_del_mem_rsv():  %s\n",
                                        fdt_strerror(err));
                                return err;
                        }
                } else {
                        /* Unrecognized command */
                        return CMD_RET_USAGE;
                }
        }
#ifdef CONFIG_OF_BOARD_SETUP
        /* Call the board-specific fixup routine */
        else if (strncmp(argv[1], "boa", 3) == 0) {
                int err = ft_board_setup(working_fdt, gd->bd);

                if (err) {
                        printf("Failed to update board information in FDT: %s\n",
                               fdt_strerror(err));
                        return CMD_RET_FAILURE;
                }
#ifdef CONFIG_ARCH_KEYSTONE
                ft_board_setup_ex(working_fdt, gd->bd);
#endif
        }
#endif
        /* Create a chosen node */
        else if (strncmp(argv[1], "cho", 3) == 0) {
                unsigned long initrd_start = 0, initrd_end = 0;

                if ((argc != 2) && (argc != 4))
                        return CMD_RET_USAGE;

                if (argc == 4) {
                        initrd_start = hextoul(argv[2], NULL);
                        initrd_end = hextoul(argv[3], NULL);
                }

                fdt_chosen(working_fdt);
                fdt_initrd(working_fdt, initrd_start, initrd_end);

#if defined(CONFIG_FIT_SIGNATURE)
        } else if (strncmp(argv[1], "che", 3) == 0) {
                int cfg_noffset;
                int ret;
                unsigned long addr;
                struct fdt_header *blob;

                if (!working_fdt)
                        return CMD_RET_FAILURE;

                if (argc > 2) {
                        addr = hextoul(argv[2], NULL);
                        blob = map_sysmem(addr, 0);
                } else {
                        blob = (struct fdt_header *)gd->fdt_blob;
                }
                if (!fdt_valid(&blob))
                        return 1;

                gd->fdt_blob = blob;
                cfg_noffset = fit_conf_get_node(working_fdt, NULL);
                if (!cfg_noffset) {
                        printf("Could not find configuration node: %s\n",
                               fdt_strerror(cfg_noffset));
                        return CMD_RET_FAILURE;
                }

                ret = fit_config_verify(working_fdt, cfg_noffset);
                if (ret == 0)
                        return CMD_RET_SUCCESS;
                else
                        return CMD_RET_FAILURE;
#endif

        }
#ifdef CONFIG_OF_LIBFDT_OVERLAY
        /* apply an overlay */
        else if (strncmp(argv[1], "ap", 2) == 0) {
                unsigned long addr;
                struct fdt_header *blob;
                int ret;

                if (argc != 3)
                        return CMD_RET_USAGE;

                if (!working_fdt)
                        return CMD_RET_FAILURE;

                addr = hextoul(argv[2], NULL);
                blob = map_sysmem(addr, 0);
                if (!fdt_valid(&blob))
                        return CMD_RET_FAILURE;

                /* apply method prints messages on error */
                ret = fdt_overlay_apply_verbose(working_fdt, blob);
                if (ret)
                        return CMD_RET_FAILURE;
        }
#endif
        /* resize the fdt */
        else if (strncmp(argv[1], "re", 2) == 0) {
                uint extrasize;
                if (argc > 2)
                        extrasize = hextoul(argv[2], NULL);
                else
                        extrasize = 0;
                fdt_shrink_to_minimum(working_fdt, extrasize);
        }
        else {
                /* Unrecognized command */
                return CMD_RET_USAGE;
        }

        return 0;
}

/****************************************************************************/

/*
 * Parse the user's input, partially heuristic.  Valid formats:
 * <0x00112233 4 05>    - an array of cells.  Numbers follow standard
 *                      C conventions.
 * [00 11 22 .. nn] - byte stream
 * "string"     - If the the value doesn't start with "<" or "[", it is
 *                      treated as a string.  Note that the quotes are
 *                      stripped by the parser before we get the string.
 * newval: An array of strings containing the new property as specified
 *      on the command line
 * count: The number of strings in the array
 * data: A bytestream to be placed in the property
 * len: The length of the resulting bytestream
 */
static int fdt_parse_prop(char * const *newval, int count, char *data, int *len)
{
        char *cp;               /* temporary char pointer */
        char *newp;             /* temporary newval char pointer */
        unsigned long tmp;      /* holds converted values */
        int stridx = 0;

        *len = 0;
        newp = newval[0];

        /* An array of cells */
        if (*newp == '<') {
                newp++;
                while ((*newp != '>') && (stridx < count)) {
                        /*
                         * Keep searching until we find that last ">"
                         * That way users don't have to escape the spaces
                         */
                        if (*newp == '\0') {
                                newp = newval[++stridx];
                                continue;
                        }

                        cp = newp;
                        tmp = simple_strtoul(cp, &newp, 0);
                        if (*cp != '?')
                                *(fdt32_t *)data = cpu_to_fdt32(tmp);
                        else
                                newp++;

                        data  += 4;
                        *len += 4;

                        /* If the ptr didn't advance, something went wrong */
                        if ((newp - cp) <= 0) {
                                printf("Sorry, I could not convert \"%s\"\n",
                                        cp);
                                return 1;
                        }

                        while (*newp == ' ')
                                newp++;
                }

                if (*newp != '>') {
                        printf("Unexpected character '%c'\n", *newp);
                        return 1;
                }
        } else if (*newp == '[') {
                /*
                 * Byte stream.  Convert the values.
                 */
                newp++;
                while ((stridx < count) && (*newp != ']')) {
                        while (*newp == ' ')
                                newp++;
                        if (*newp == '\0') {
                                newp = newval[++stridx];
                                continue;
                        }
                        if (!isxdigit(*newp))
                                break;
                        tmp = hextoul(newp, &newp);
                        *data++ = tmp & 0xFF;
                        *len    = *len + 1;
                }
                if (*newp != ']') {
                        printf("Unexpected character '%c'\n", *newp);
                        return 1;
                }
        } else {
                /*
                 * Assume it is one or more strings.  Copy it into our
                 * data area for convenience (including the
                 * terminating '\0's).
                 */
                while (stridx < count) {
                        size_t length = strlen(newp) + 1;
                        strcpy(data, newp);
                        data += length;
                        *len += length;
                        newp = newval[++stridx];
                }
        }
        return 0;
}

/****************************************************************************/

/*
 * Heuristic to guess if this is a string or concatenated strings.
 */

static int is_printable_string(const void *data, int len)
{
        const char *s = data;

        /* zero length is not */
        if (len == 0)
                return 0;

        /* must terminate with zero or '\n' */
        if (s[len - 1] != '\0' && s[len - 1] != '\n')
                return 0;

        /* printable or a null byte (concatenated strings) */
        while (((*s == '\0') || isprint(*s) || isspace(*s)) && (len > 0)) {
                /*
                 * If we see a null, there are three possibilities:
                 * 1) If len == 1, it is the end of the string, printable
                 * 2) Next character also a null, not printable.
                 * 3) Next character not a null, continue to check.
                 */
                if (s[0] == '\0') {
                        if (len == 1)
                                return 1;
                        if (s[1] == '\0')
                                return 0;
                }
                s++;
                len--;
        }

        /* Not the null termination, or not done yet: not printable */
        if (*s != '\0' || (len != 0))
                return 0;

        return 1;
}


/*
 * Print the property in the best format, a heuristic guess.  Print as
 * a string, concatenated strings, a byte, word, double word, or (if all
 * else fails) it is printed as a stream of bytes.
 */
static void print_data(const void *data, int len)
{
        int j;
        const char *env_max_dump;
        ulong max_dump = ULONG_MAX;

        /* no data, don't print */
        if (len == 0)
                return;

        env_max_dump = env_get("fdt_max_dump");
        if (env_max_dump)
                max_dump = hextoul(env_max_dump, NULL);

        /*
         * It is a string, but it may have multiple strings (embedded '\0's).
         */
        if (is_printable_string(data, len)) {
                puts("\"");
                j = 0;
                while (j < len) {
                        if (j > 0)
                                puts("\", \"");
                        puts(data);
                        j    += strlen(data) + 1;
                        data += strlen(data) + 1;
                }
                puts("\"");
                return;
        }

        if ((len %4) == 0) {
                if (len > max_dump)
                        printf("* 0x%p [0x%08x]", data, len);
                else {
                        const __be32 *p;

                        printf("<");
                        for (j = 0, p = data; j < len/4; j++)
                                printf("0x%08x%s", fdt32_to_cpu(p[j]),
                                        j < (len/4 - 1) ? " " : "");
                        printf(">");
                }
        } else { /* anything else... hexdump */
                if (len > max_dump)
                        printf("* 0x%p [0x%08x]", data, len);
                else {
                        const u8 *s;

                        printf("[");
                        for (j = 0, s = data; j < len; j++)
                                printf("%02x%s", s[j], j < len - 1 ? " " : "");
                        printf("]");
                }
        }
}

/****************************************************************************/

/*
 * Recursively print (a portion of) the working_fdt.  The depth parameter
 * determines how deeply nested the fdt is printed.
 */
static int fdt_print(const char *pathp, char *prop, int depth)
{
        static char tabs[MAX_LEVEL+1] =
                "\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t"
                "\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t";
        const void *nodep;      /* property node pointer */
        int  nodeoffset;        /* node offset from libfdt */
        int  nextoffset;        /* next node offset from libfdt */
        uint32_t tag;           /* tag */
        int  len;               /* length of the property */
        int  level = 0;         /* keep track of nesting level */
        const struct fdt_property *fdt_prop;

        nodeoffset = fdt_path_offset (working_fdt, pathp);
        if (nodeoffset < 0) {
                /*
                 * Not found or something else bad happened.
                 */
                printf ("libfdt fdt_path_offset() returned %s\n",
                        fdt_strerror(nodeoffset));
                return 1;
        }
        /*
         * The user passed in a property as well as node path.
         * Print only the given property and then return.
         */
        if (prop) {
                nodep = fdt_getprop (working_fdt, nodeoffset, prop, &len);
                if (len == 0) {
                        /* no property value */
                        printf("%s %s\n", pathp, prop);
                        return 0;
                } else if (nodep && len > 0) {
                        printf("%s = ", prop);
                        print_data (nodep, len);
                        printf("\n");
                        return 0;
                } else {
                        printf ("libfdt fdt_getprop(): %s\n",
                                fdt_strerror(len));
                        return 1;
                }
        }

        /*
         * The user passed in a node path and no property,
         * print the node and all subnodes.
         */
        while(level >= 0) {
                tag = fdt_next_tag(working_fdt, nodeoffset, &nextoffset);
                switch(tag) {
                case FDT_BEGIN_NODE:
                        pathp = fdt_get_name(working_fdt, nodeoffset, NULL);
                        if (level <= depth) {
                                if (pathp == NULL)
                                        pathp = "/* NULL pointer error */";
                                if (*pathp == '\0')
                                        pathp = "/";    /* root is nameless */
                                printf("%s%s {\n",
                                        &tabs[MAX_LEVEL - level], pathp);
                        }
                        level++;
                        if (level >= MAX_LEVEL) {

                                printf("Nested too deep, aborting.\n");
                                return 1;
                        }
                        break;
                case FDT_END_NODE:
                        level--;
                        if (level <= depth)
                                printf("%s};\n", &tabs[MAX_LEVEL - level]);
                        if (level == 0) {
                                level = -1;             /* exit the loop */
                        }
                        break;
                case FDT_PROP:
                        fdt_prop = fdt_offset_ptr(working_fdt, nodeoffset,
                                        sizeof(*fdt_prop));
                        pathp    = fdt_string(working_fdt,
                                        fdt32_to_cpu(fdt_prop->nameoff));
                        len      = fdt32_to_cpu(fdt_prop->len);
                        nodep    = fdt_prop->data;
                        if (len < 0) {
                                printf ("libfdt fdt_getprop(): %s\n",
                                        fdt_strerror(len));
                                return 1;
                        } else if (len == 0) {
                                /* the property has no value */
                                if (level <= depth)
                                        printf("%s%s;\n",
                                                &tabs[MAX_LEVEL - level],
                                                pathp);
                        } else {
                                if (level <= depth) {
                                        printf("%s%s = ",
                                                &tabs[MAX_LEVEL - level],
                                                pathp);
                                        print_data (nodep, len);
                                        printf(";\n");
                                }
                        }
                        break;
                case FDT_NOP:
                        printf("%s/* NOP */\n", &tabs[MAX_LEVEL - level]);
                        break;
                case FDT_END:
                        return 1;
                default:
                        if (level <= depth)
                                printf("Unknown tag 0x%08X\n", tag);
                        return 1;
                }
                nodeoffset = nextoffset;
        }
        return 0;
}

/********************************************************************/
#ifdef CONFIG_SYS_LONGHELP
static char fdt_help_text[] =
        "addr [-c]  <addr> [<length>]   - Set the [control] fdt location to <addr>\n"
#ifdef CONFIG_OF_LIBFDT_OVERLAY
        "fdt apply <addr>                    - Apply overlay to the DT\n"
#endif
#ifdef CONFIG_OF_BOARD_SETUP
        "fdt boardsetup                      - Do board-specific set up\n"
#endif
#ifdef CONFIG_OF_SYSTEM_SETUP
        "fdt systemsetup                     - Do system-specific set up\n"
#endif
        "fdt move   <fdt> <newaddr> <length> - Copy the fdt to <addr> and make it active\n"
        "fdt resize [<extrasize>]            - Resize fdt to size + padding to 4k addr + some optional <extrasize> if needed\n"
        "fdt print  <path> [<prop>]          - Recursive print starting at <path>\n"
        "fdt list   <path> [<prop>]          - Print one level starting at <path>\n"
        "fdt get value <var> <path> <prop>   - Get <property> and store in <var>\n"
        "fdt get name <var> <path> <index>   - Get name of node <index> and store in <var>\n"
        "fdt get addr <var> <path> <prop>    - Get start address of <property> and store in <var>\n"
        "fdt get size <var> <path> [<prop>]  - Get size of [<property>] or num nodes and store in <var>\n"
        "fdt set    <path> <prop> [<val>]    - Set <property> [to <val>]\n"
        "fdt mknode <path> <node>            - Create a new node after <path>\n"
        "fdt rm     <path> [<prop>]          - Delete the node or <property>\n"
        "fdt header [get <var> <member>]     - Display header info\n"
        "                                      get - get header member <member> and store it in <var>\n"
        "fdt bootcpu <id>                    - Set boot cpuid\n"
        "fdt memory <addr> <size>            - Add/Update memory node\n"
        "fdt rsvmem print                    - Show current mem reserves\n"
        "fdt rsvmem add <addr> <size>        - Add a mem reserve\n"
        "fdt rsvmem delete <index>           - Delete a mem reserves\n"
        "fdt chosen [<start> <end>]          - Add/update the /chosen branch in the tree\n"
        "                                        <start>/<end> - initrd start/end addr\n"
#if defined(CONFIG_FIT_SIGNATURE)
        "fdt checksign [<addr>]              - check FIT signature\n"
        "                                        <start> - addr of key blob\n"
        "                                                  default gd->fdt_blob\n"
#endif
        "NOTE: Dereference aliases by omitting the leading '/', "
                "e.g. fdt print ethernet0.";
#endif

U_BOOT_CMD(
        fdt,    255,    0,      do_fdt,
        "flattened device tree utility commands", fdt_help_text
);