1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (c) 2015, Sony Mobile Communications Inc.
4 * Copyright (c) 2012-2013, The Linux Foundation. All rights reserved.
5 */
6#include <linux/device.h>
7#include <linux/list.h>
8#include <linux/module.h>
9#include <linux/of.h>
10#include <linux/slab.h>
11#include <linux/soc/qcom/smem_state.h>
12
13static LIST_HEAD(smem_states);
14static DEFINE_MUTEX(list_lock);
15
16/**
17 * struct qcom_smem_state - state context
18 * @refcount:	refcount for the state
19 * @orphan:	boolean indicator that this state has been unregistered
20 * @list:	entry in smem_states list
21 * @of_node:	of_node to use for matching the state in DT
22 * @priv:	implementation private data
23 * @ops:	ops for the state
24 */
25struct qcom_smem_state {
26	struct kref refcount;
27	bool orphan;
28
29	struct list_head list;
30	struct device_node *of_node;
31
32	void *priv;
33
34	struct qcom_smem_state_ops ops;
35};
36
37/**
38 * qcom_smem_state_update_bits() - update the masked bits in state with value
39 * @state:	state handle acquired by calling qcom_smem_state_get()
40 * @mask:	bit mask for the change
41 * @value:	new value for the masked bits
42 *
43 * Returns 0 on success, otherwise negative errno.
44 */
45int qcom_smem_state_update_bits(struct qcom_smem_state *state,
46				u32 mask,
47				u32 value)
48{
49	if (state->orphan)
50		return -ENXIO;
51
52	if (!state->ops.update_bits)
53		return -ENOTSUPP;
54
55	return state->ops.update_bits(state->priv, mask, value);
56}
57EXPORT_SYMBOL_GPL(qcom_smem_state_update_bits);
58
59static struct qcom_smem_state *of_node_to_state(struct device_node *np)
60{
61	struct qcom_smem_state *state;
62
63	mutex_lock(&list_lock);
64
65	list_for_each_entry(state, &smem_states, list) {
66		if (state->of_node == np) {
67			kref_get(&state->refcount);
68			goto unlock;
69		}
70	}
71	state = ERR_PTR(-EPROBE_DEFER);
72
73unlock:
74	mutex_unlock(&list_lock);
75
76	return state;
77}
78
79/**
80 * qcom_smem_state_get() - acquire handle to a state
81 * @dev:	client device pointer
82 * @con_id:	name of the state to lookup
83 * @bit:	flags from the state reference, indicating which bit's affected
84 *
85 * Returns handle to the state, or ERR_PTR(). qcom_smem_state_put() must be
86 * called to release the returned state handle.
87 */
88struct qcom_smem_state *qcom_smem_state_get(struct device *dev,
89					    const char *con_id,
90					    unsigned *bit)
91{
92	struct qcom_smem_state *state;
93	struct of_phandle_args args;
94	int index = 0;
95	int ret;
96
97	if (con_id) {
98		index = of_property_match_string(dev->of_node,
99						 "qcom,smem-state-names",
100						 con_id);
101		if (index < 0) {
102			dev_err(dev, "missing qcom,smem-state-names\n");
103			return ERR_PTR(index);
104		}
105	}
106
107	ret = of_parse_phandle_with_args(dev->of_node,
108					 "qcom,smem-states",
109					 "#qcom,smem-state-cells",
110					 index,
111					 &args);
112	if (ret) {
113		dev_err(dev, "failed to parse qcom,smem-states property\n");
114		return ERR_PTR(ret);
115	}
116
117	if (args.args_count != 1) {
118		dev_err(dev, "invalid #qcom,smem-state-cells\n");
119		return ERR_PTR(-EINVAL);
120	}
121
122	state = of_node_to_state(args.np);
123	if (IS_ERR(state))
124		goto put;
125
126	*bit = args.args[0];
127
128put:
129	of_node_put(args.np);
130	return state;
131}
132EXPORT_SYMBOL_GPL(qcom_smem_state_get);
133
134static void qcom_smem_state_release(struct kref *ref)
135{
136	struct qcom_smem_state *state = container_of(ref, struct qcom_smem_state, refcount);
137
138	list_del(&state->list);
139	of_node_put(state->of_node);
140	kfree(state);
141}
142
143/**
144 * qcom_smem_state_put() - release state handle
145 * @state:	state handle to be released
146 */
147void qcom_smem_state_put(struct qcom_smem_state *state)
148{
149	mutex_lock(&list_lock);
150	kref_put(&state->refcount, qcom_smem_state_release);
151	mutex_unlock(&list_lock);
152}
153EXPORT_SYMBOL_GPL(qcom_smem_state_put);
154
155/**
156 * qcom_smem_state_register() - register a new state
157 * @of_node:	of_node used for matching client lookups
158 * @ops:	implementation ops
159 * @priv:	implementation specific private data
160 */
161struct qcom_smem_state *qcom_smem_state_register(struct device_node *of_node,
162						 const struct qcom_smem_state_ops *ops,
163						 void *priv)
164{
165	struct qcom_smem_state *state;
166
167	state = kzalloc(sizeof(*state), GFP_KERNEL);
168	if (!state)
169		return ERR_PTR(-ENOMEM);
170
171	kref_init(&state->refcount);
172
173	state->of_node = of_node_get(of_node);
174	state->ops = *ops;
175	state->priv = priv;
176
177	mutex_lock(&list_lock);
178	list_add(&state->list, &smem_states);
179	mutex_unlock(&list_lock);
180
181	return state;
182}
183EXPORT_SYMBOL_GPL(qcom_smem_state_register);
184
185/**
186 * qcom_smem_state_unregister() - unregister a registered state
187 * @state:	state handle to be unregistered
188 */
189void qcom_smem_state_unregister(struct qcom_smem_state *state)
190{
191	state->orphan = true;
192	qcom_smem_state_put(state);
193}
194EXPORT_SYMBOL_GPL(qcom_smem_state_unregister);
195