/*
 * Copyright (c) 2011 The Chromium OS Authors. All rights reserved.
 *
 * Portions from U-Boot cmd_fdt.c (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>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of
 * the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
 * MA 02111-1307 USA
 */

#include <assert.h>
#include <ctype.h>
#include <getopt.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <libfdt.h>

#include "util.h"

enum display_mode {
        MODE_SHOW_VALUE,        /* show values for node properties */
        MODE_LIST_PROPS,        /* list the properties for a node */
        MODE_LIST_SUBNODES,     /* list the subnodes of a node */
};

/* Holds information which controls our output and options */
struct display_info {
        int type;               /* data type (s/i/u/x or 0 for default) */
        int size;               /* data size (1/2/4) */
        enum display_mode mode; /* display mode that we are using */
        const char *default_val; /* default value if node/property not found */
};

static void report_error(const char *where, int err)
{
        fprintf(stderr, "Error at '%s': %s\n", where, fdt_strerror(err));
}

/**
 * Displays data of a given length according to selected options
 *
 * If a specific data type is provided in disp, then this is used. Otherwise
 * we try to guess the data type / size from the contents.
 *
 * @param disp          Display information / options
 * @param data          Data to display
 * @param len           Maximum length of buffer
 * @return 0 if ok, -1 if data does not match format
 */
static int show_data(struct display_info *disp, const char *data, int len)
{
        int i, size;
        const uint8_t *p = (const uint8_t *)data;
        const char *s;
        int value;
        int is_string;
        char fmt[3];

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

        is_string = (disp->type) == 's' ||
                (!disp->type && util_is_printable_string(data, len));
        if (is_string) {
                if (data[len - 1] != '\0') {
                        fprintf(stderr, "Unterminated string\n");
                        return -1;
                }
                for (s = data; s - data < len; s += strlen(s) + 1) {
                        if (s != data)
                                printf(" ");
                        printf("%s", (const char *)s);
                }
                return 0;
        }
        size = disp->size;
        if (size == -1) {
                size = (len % 4) == 0 ? 4 : 1;
        } else if (len % size) {
                fprintf(stderr, "Property length must be a multiple of "
                                "selected data size\n");
                return -1;
        }
        fmt[0] = '%';
        fmt[1] = disp->type ? disp->type : 'd';
        fmt[2] = '\0';
        for (i = 0; i < len; i += size, p += size) {
                if (i)
                        printf(" ");
                value = size == 4 ? fdt32_to_cpu(*(const uint32_t *)p) :
                        size == 2 ? (*p << 8) | p[1] : *p;
                printf(fmt, value);
        }
        return 0;
}

/**
 * List all properties in a node, one per line.
 *
 * @param blob          FDT blob
 * @param node          Node to display
 * @return 0 if ok, or FDT_ERR... if not.
 */
static int list_properties(const void *blob, int node)
{
        const struct fdt_property *data;
        const char *name;
        int prop;

        prop = fdt_first_property_offset(blob, node);
        do {
                /* Stop silently when there are no more properties */
                if (prop < 0)
                        return prop == -FDT_ERR_NOTFOUND ? 0 : prop;
                data = fdt_get_property_by_offset(blob, prop, NULL);
                name = fdt_string(blob, fdt32_to_cpu(data->nameoff));
                if (name)
                        puts(name);
                prop = fdt_next_property_offset(blob, prop);
        } while (1);
}

#define MAX_LEVEL       32              /* how deeply nested we will go */

/**
 * List all subnodes in a node, one per line
 *
 * @param blob          FDT blob
 * @param node          Node to display
 * @return 0 if ok, or FDT_ERR... if not.
 */
static int list_subnodes(const void *blob, int node)
{
        int nextoffset;         /* next node offset from libfdt */
        uint32_t tag;           /* current tag */
        int level = 0;          /* keep track of nesting level */
        const char *pathp;
        int depth = 1;          /* the assumed depth of this node */

        while (level >= 0) {
                tag = fdt_next_tag(blob, node, &nextoffset);
                switch (tag) {
                case FDT_BEGIN_NODE:
                        pathp = fdt_get_name(blob, node, NULL);
                        if (level <= depth) {
                                if (pathp == NULL)
                                        pathp = "/* NULL pointer error */";
                                if (*pathp == '\0')
                                        pathp = "/";    /* root is nameless */
                                if (level == 1)
                                        puts(pathp);
                        }
                        level++;
                        if (level >= MAX_LEVEL) {
                                printf("Nested too deep, aborting.\n");
                                return 1;
                        }
                        break;
                case FDT_END_NODE:
                        level--;
                        if (level == 0)
                                level = -1;             /* exit the loop */
                        break;
                case FDT_END:
                        return 1;
                case FDT_PROP:
                        break;
                default:
                        if (level <= depth)
                                printf("Unknown tag 0x%08X\n", tag);
                        return 1;
                }
                node = nextoffset;
        }
        return 0;
}

/**
 * Show the data for a given node (and perhaps property) according to the
 * display option provided.
 *
 * @param blob          FDT blob
 * @param disp          Display information / options
 * @param node          Node to display
 * @param property      Name of property to display, or NULL if none
 * @return 0 if ok, -ve on error
 */
static int show_data_for_item(const void *blob, struct display_info *disp,
                int node, const char *property)
{
        const void *value = NULL;
        int len, err = 0;

        switch (disp->mode) {
        case MODE_LIST_PROPS:
                err = list_properties(blob, node);
                break;

        case MODE_LIST_SUBNODES:
                err = list_subnodes(blob, node);
                break;

        default:
                assert(property);
                value = fdt_getprop(blob, node, property, &len);
                if (value) {
                        if (show_data(disp, value, len))
                                err = -1;
                        else
                                printf("\n");
                } else if (disp->default_val) {
                        puts(disp->default_val);
                } else {
                        report_error(property, len);
                        err = -1;
                }
                break;
        }

        return err;
}

/**
 * Run the main fdtget operation, given a filename and valid arguments
 *
 * @param disp          Display information / options
 * @param filename      Filename of blob file
 * @param arg           List of arguments to process
 * @param arg_count     Number of arguments
 * @param return 0 if ok, -ve on error
 */
static int do_fdtget(struct display_info *disp, const char *filename,
                     char **arg, int arg_count, int args_per_step)
{
        char *blob;
        const char *prop;
        int i, node;

        blob = utilfdt_read(filename);
        if (!blob)
                return -1;

        for (i = 0; i + args_per_step <= arg_count; i += args_per_step) {
                node = fdt_path_offset(blob, arg[i]);
                if (node < 0) {
                        if (disp->default_val) {
                                puts(disp->default_val);
                                continue;
                        } else {
                                report_error(arg[i], node);
                                return -1;
                        }
                }
                prop = args_per_step == 1 ? NULL : arg[i + 1];

                if (show_data_for_item(blob, disp, node, prop))
                        return -1;
        }
        return 0;
}

static const char *usage_msg =
        "fdtget - read values from device tree\n"
        "\n"
        "Each value is printed on a new line.\n\n"
        "Usage:\n"
        "       fdtget <options> <dt file> [<node> <property>]...\n"
        "       fdtget -p <options> <dt file> [<node> ]...\n"
        "Options:\n"
        "\t-t <type>\tType of data\n"
        "\t-p\t\tList properties for each node\n"
        "\t-l\t\tList subnodes for each node\n"
        "\t-d\t\tDefault value to display when the property is "
                        "missing\n"
        "\t-h\t\tPrint this help\n\n"
        USAGE_TYPE_MSG;

static void usage(const char *msg)
{
        if (msg)
                fprintf(stderr, "Error: %s\n\n", msg);

        fprintf(stderr, "%s", usage_msg);
        exit(2);
}

int main(int argc, char *argv[])
{
        char *filename = NULL;
        struct display_info disp;
        int args_per_step = 2;

        /* set defaults */
        memset(&disp, '\0', sizeof(disp));
        disp.size = -1;
        disp.mode = MODE_SHOW_VALUE;
        for (;;) {
                int c = getopt(argc, argv, "d:hlpt:");
                if (c == -1)
                        break;

                switch (c) {
                case 'h':
                case '?':
                        usage(NULL);

                case 't':
                        if (utilfdt_decode_type(optarg, &disp.type,
                                        &disp.size))
                                usage("Invalid type string");
                        break;

                case 'p':
                        disp.mode = MODE_LIST_PROPS;
                        args_per_step = 1;
                        break;

                case 'l':
                        disp.mode = MODE_LIST_SUBNODES;
                        args_per_step = 1;
                        break;

                case 'd':
                        disp.default_val = optarg;
                        break;
                }
        }

        if (optind < argc)
                filename = argv[optind++];
        if (!filename)
                usage("Missing filename");

        argv += optind;
        argc -= optind;

        /* Allow no arguments, and silently succeed */
        if (!argc)
                return 0;

        /* Check for node, property arguments */
        if (args_per_step == 2 && (argc % 2))
                usage("Must have an even number of arguments");

        if (do_fdtget(&disp, filename, argv, argc, args_per_step))
                return 1;
        return 0;
}