LXR dpdk/drivers/bus/dpaa/include/dpaa

   1/* SPDX-License-Identifier: BSD-3-Clause
   2 *
   3 *   Copyright 2017 NXP
   4 *
   5 */
   6
   7#ifndef __DPAA_RBTREE_H
   8#define __DPAA_RBTREE_H
   9
  10#include <rte_common.h>
  11/************/
  12/* RB-trees */
  13/************/
  14
  15/* Linux has a good RB-tree implementation, that we can't use (GPL). It also has
  16 * a flat/hooked-in interface that virtually requires license-contamination in
  17 * order to write a caller-compatible implementation. Instead, I've created an
  18 * RB-tree encapsulation on top of linux's primitives (it does some of the work
  19 * the client logic would normally do), and this gives us something we can
  20 * reimplement on LWE. Unfortunately there's no good+free RB-tree
  21 * implementations out there that are license-compatible and "flat" (ie. no
  22 * dynamic allocation). I did find a malloc-based one that I could convert, but
  23 * that will be a task for later on. For now, LWE's RB-tree is implemented using
  24 * an ordered linked-list.
  25 *
  26 * Note, the only linux-esque type is "struct rb_node", because it's used
  27 * statically in the exported header, so it can't be opaque. Our version doesn't
  28 * include a "rb_parent_color" field because we're doing linked-list instead of
  29 * a true rb-tree.
  30 */
  31
  32struct rb_node {
  33        struct rb_node *prev, *next;
  34};
  35
  36struct dpa_rbtree {
  37        struct rb_node *head, *tail;
  38};
  39
  40#define DPAA_RBTREE { NULL, NULL }
  41static inline void dpa_rbtree_init(struct dpa_rbtree *tree)
  42{
  43        tree->head = tree->tail = NULL;
  44}
  45
  46#define QMAN_NODE2OBJ(ptr, type, node_field) \
  47        (type *)((char *)ptr - offsetof(type, node_field))
  48
  49#define IMPLEMENT_DPAA_RBTREE(name, type, node_field, val_field) \
  50static inline int name##_push(struct dpa_rbtree *tree, type *obj) \
  51{ \
  52        struct rb_node *node = tree->head; \
  53        if (!node) { \
  54                tree->head = tree->tail = &obj->node_field; \
  55                obj->node_field.prev = obj->node_field.next = NULL; \
  56                return 0; \
  57        } \
  58        while (node) { \
  59                type *item = QMAN_NODE2OBJ(node, type, node_field); \
  60                if (obj->val_field == item->val_field) \
  61                        return -EBUSY; \
  62                if (obj->val_field < item->val_field) { \
  63                        if (tree->head == node) \
  64                                tree->head = &obj->node_field; \
  65                        else \
  66                                node->prev->next = &obj->node_field; \
  67                        obj->node_field.prev = node->prev; \
  68                        obj->node_field.next = node; \
  69                        node->prev = &obj->node_field; \
  70                        return 0; \
  71                } \
  72                node = node->next; \
  73        } \
  74        obj->node_field.prev = tree->tail; \
  75        obj->node_field.next = NULL; \
  76        tree->tail->next = &obj->node_field; \
  77        tree->tail = &obj->node_field; \
  78        return 0; \
  79} \
  80static inline void name##_del(struct dpa_rbtree *tree, type *obj) \
  81{ \
  82        if (tree->head == &obj->node_field) { \
  83                if (tree->tail == &obj->node_field) \
  84                        /* Only item in the list */ \
  85                        tree->head = tree->tail = NULL; \
  86                else { \
  87                        /* Is the head, next != NULL */ \
  88                        tree->head = tree->head->next; \
  89                        tree->head->prev = NULL; \
  90                } \
  91        } else { \
  92                if (tree->tail == &obj->node_field) { \
  93                        /* Is the tail, prev != NULL */ \
  94                        tree->tail = tree->tail->prev; \
  95                        tree->tail->next = NULL; \
  96                } else { \
  97                        /* Is neither the head nor the tail */ \
  98                        obj->node_field.prev->next = obj->node_field.next; \
  99                        obj->node_field.next->prev = obj->node_field.prev; \
 100                } \
 101        } \
 102} \
 103static inline type *name##_find(struct dpa_rbtree *tree, u32 val) \
 104{ \
 105        struct rb_node *node = tree->head; \
 106        while (node) { \
 107                type *item = QMAN_NODE2OBJ(node, type, node_field); \
 108                if (val == item->val_field) \
 109                        return item; \
 110                if (val < item->val_field) \
 111                        return NULL; \
 112                node = node->next; \
 113        } \
 114        return NULL; \
 115}
 116
 117#endif /* __DPAA_RBTREE_H */
 118