/* SPDX-License-Identifier: Apache-2.0
 * Copyright (c) 2024 Cisco Systems, Inc.
 */

#ifndef CLIB_DEVICETREE_H_
#define CLIB_DEVICETREE_H_

#include <vppinfra/clib.h>
#include <vlib/vlib.h>

#ifdef __linux
#define CLIB_DT_LINUX_PREFIX "/sys/firmware/devicetree/base"
#endif

typedef struct
{
  char name[32];
  u32 size;
  u8 data[];
} clib_dt_property_t;

typedef struct clib_dt_main clib_dt_main_t;

typedef struct clib_dt_node
{
  u8 *path;
  struct clib_dt_node *parent;
  struct clib_dt_node *prev;
  struct clib_dt_node *next;
  struct clib_dt_node **child_nodes;
  u8 depth;
  clib_dt_property_t *name;
  clib_dt_property_t **properties;
  clib_dt_main_t *dt_main;
} clib_dt_node_t;

typedef struct clib_dt_main
{
  clib_dt_node_t **nodes;
  clib_dt_node_t *root;
  uword *node_by_path;
  uword *node_by_phandle;
} clib_dt_main_t;

__clib_export clib_dt_node_t *clib_dt_get_child_node (clib_dt_node_t *n,
						      char *fmt, ...);
clib_dt_node_t *clib_dt_get_node_with_path (clib_dt_main_t *dm, char *fmt,
					    ...);
clib_dt_property_t *clib_dt_get_node_property_by_name (clib_dt_node_t *,
						       char *);
int clib_dt_node_is_compatible (clib_dt_node_t *, char *);
clib_dt_node_t *clib_dt_dereference_node (clib_dt_node_t *, char *);
#ifdef __linux
clib_error_t *clib_dt_read_from_sysfs (clib_dt_main_t *dm);
#endif

format_function_t format_clib_dt_desc;
format_function_t format_clib_dt_property_data;

static_always_inline int
clib_dt_property_is_u32 (clib_dt_property_t *p)
{
  if (p == 0 || p->size != 4)
    return 0;
  return 1;
}

static_always_inline u32
clib_dt_property_get_u32 (clib_dt_property_t *p)
{
  return clib_net_to_host_u32 (*(u32u *) p->data);
}

static_always_inline char *
clib_dt_property_get_string (clib_dt_property_t *p)
{
  return (char *) p->data;
}

static_always_inline clib_dt_node_t *
clib_dt_get_root_node (clib_dt_node_t *n)
{
  return n->dt_main->root;
}

static_always_inline clib_dt_node_t *
foreach_clib_dt_tree_node_helper (clib_dt_node_t *first, clib_dt_node_t **prev,
				  clib_dt_node_t *n)
{
  clib_dt_node_t *next;

again:
  if ((!*prev || (*prev)->parent != n) && vec_len (n->child_nodes) > 0)
    next = n->child_nodes[0];
  else if (n->next)
    next = n->next;
  else
    {
      next = n->parent;
      *prev = n;
      n = next;
      if (n == first)
	return 0;
      goto again;
    }

  *prev = n;
  return next == first ? 0 : next;
}

#define foreach_clib_dt_child_node(_cn, _n)                                   \
  vec_foreach_pointer (_cn, (_n)->child_nodes)

#define foreach_clib_dt_tree_node(_n, _first)                                 \
  for (clib_dt_node_t *__last = 0, *(_n) = _first; _n;                        \
       _n = foreach_clib_dt_tree_node_helper (_first, &__last, _n))

#endif /* CLIB_DEVICETREE_H_ */