1 /* Copyright (c) 2017-2018, The Linux Foundation. All rights reserved.
2 *
3 * This program is free software; you can redistribute it and/or modify
4 * it under the terms of the GNU General Public License version 2 and
5 * only version 2 as published by the Free Software Foundation.
6 *
7 * This program is distributed in the hope that it will be useful,
8 * but WITHOUT ANY WARRANTY; without even the implied warranty of
9 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
10 * GNU General Public License for more details.
11 */
12
13 #define pr_fmt(fmt) "[drm:%s:%d] " fmt, __func__, __LINE__
14
15 #include <linux/mutex.h>
16 #include <linux/errno.h>
17 #include <linux/slab.h>
18
19 #include "dpu_hw_mdss.h"
20 #include "dpu_hw_blk.h"
21
22 /* Serialization lock for dpu_hw_blk_list */
23 static DEFINE_MUTEX(dpu_hw_blk_lock);
24
25 /* List of all hw block objects */
26 static LIST_HEAD(dpu_hw_blk_list);
27
28 /**
29 * dpu_hw_blk_init - initialize hw block object
30 * @type: hw block type - enum dpu_hw_blk_type
31 * @id: instance id of the hw block
32 * @ops: Pointer to block operations
33 * return: 0 if success; error code otherwise
34 */
dpu_hw_blk_init(struct dpu_hw_blk * hw_blk,u32 type,int id,struct dpu_hw_blk_ops * ops)35 int dpu_hw_blk_init(struct dpu_hw_blk *hw_blk, u32 type, int id,
36 struct dpu_hw_blk_ops *ops)
37 {
38 if (!hw_blk) {
39 pr_err("invalid parameters\n");
40 return -EINVAL;
41 }
42
43 INIT_LIST_HEAD(&hw_blk->list);
44 hw_blk->type = type;
45 hw_blk->id = id;
46 atomic_set(&hw_blk->refcount, 0);
47
48 if (ops)
49 hw_blk->ops = *ops;
50
51 mutex_lock(&dpu_hw_blk_lock);
52 list_add(&hw_blk->list, &dpu_hw_blk_list);
53 mutex_unlock(&dpu_hw_blk_lock);
54
55 return 0;
56 }
57
58 /**
59 * dpu_hw_blk_destroy - destroy hw block object.
60 * @hw_blk: pointer to hw block object
61 * return: none
62 */
dpu_hw_blk_destroy(struct dpu_hw_blk * hw_blk)63 void dpu_hw_blk_destroy(struct dpu_hw_blk *hw_blk)
64 {
65 if (!hw_blk) {
66 pr_err("invalid parameters\n");
67 return;
68 }
69
70 if (atomic_read(&hw_blk->refcount))
71 pr_err("hw_blk:%d.%d invalid refcount\n", hw_blk->type,
72 hw_blk->id);
73
74 mutex_lock(&dpu_hw_blk_lock);
75 list_del(&hw_blk->list);
76 mutex_unlock(&dpu_hw_blk_lock);
77 }
78
79 /**
80 * dpu_hw_blk_get - get hw_blk from free pool
81 * @hw_blk: if specified, increment reference count only
82 * @type: if hw_blk is not specified, allocate the next available of this type
83 * @id: if specified (>= 0), allocate the given instance of the above type
84 * return: pointer to hw block object
85 */
dpu_hw_blk_get(struct dpu_hw_blk * hw_blk,u32 type,int id)86 struct dpu_hw_blk *dpu_hw_blk_get(struct dpu_hw_blk *hw_blk, u32 type, int id)
87 {
88 struct dpu_hw_blk *curr;
89 int rc, refcount;
90
91 if (!hw_blk) {
92 mutex_lock(&dpu_hw_blk_lock);
93 list_for_each_entry(curr, &dpu_hw_blk_list, list) {
94 if ((curr->type != type) ||
95 (id >= 0 && curr->id != id) ||
96 (id < 0 &&
97 atomic_read(&curr->refcount)))
98 continue;
99
100 hw_blk = curr;
101 break;
102 }
103 mutex_unlock(&dpu_hw_blk_lock);
104 }
105
106 if (!hw_blk) {
107 pr_debug("no hw_blk:%d\n", type);
108 return NULL;
109 }
110
111 refcount = atomic_inc_return(&hw_blk->refcount);
112
113 if (refcount == 1 && hw_blk->ops.start) {
114 rc = hw_blk->ops.start(hw_blk);
115 if (rc) {
116 pr_err("failed to start hw_blk:%d rc:%d\n", type, rc);
117 goto error_start;
118 }
119 }
120
121 pr_debug("hw_blk:%d.%d refcount:%d\n", hw_blk->type,
122 hw_blk->id, refcount);
123 return hw_blk;
124
125 error_start:
126 dpu_hw_blk_put(hw_blk);
127 return ERR_PTR(rc);
128 }
129
130 /**
131 * dpu_hw_blk_put - put hw_blk to free pool if decremented refcount is zero
132 * @hw_blk: hw block to be freed
133 * @free_blk: function to be called when reference count goes to zero
134 */
dpu_hw_blk_put(struct dpu_hw_blk * hw_blk)135 void dpu_hw_blk_put(struct dpu_hw_blk *hw_blk)
136 {
137 if (!hw_blk) {
138 pr_err("invalid parameters\n");
139 return;
140 }
141
142 pr_debug("hw_blk:%d.%d refcount:%d\n", hw_blk->type, hw_blk->id,
143 atomic_read(&hw_blk->refcount));
144
145 if (!atomic_read(&hw_blk->refcount)) {
146 pr_err("hw_blk:%d.%d invalid put\n", hw_blk->type, hw_blk->id);
147 return;
148 }
149
150 if (atomic_dec_return(&hw_blk->refcount))
151 return;
152
153 if (hw_blk->ops.stop)
154 hw_blk->ops.stop(hw_blk);
155 }
156
