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
13 static LIST_HEAD(smem_states);
14 static 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 */
25 struct 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 */
qcom_smem_state_update_bits(struct qcom_smem_state * state,u32 mask,u32 value)45 int 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 }
57 EXPORT_SYMBOL_GPL(qcom_smem_state_update_bits);
58
of_node_to_state(struct device_node * np)59 static 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
73 unlock:
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 */
qcom_smem_state_get(struct device * dev,const char * con_id,unsigned * bit)88 struct 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
128 put:
129 of_node_put(args.np);
130 return state;
131 }
132 EXPORT_SYMBOL_GPL(qcom_smem_state_get);
133
qcom_smem_state_release(struct kref * ref)134 static 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 */
qcom_smem_state_put(struct qcom_smem_state * state)147 void 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 }
153 EXPORT_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 */
qcom_smem_state_register(struct device_node * of_node,const struct qcom_smem_state_ops * ops,void * priv)161 struct 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 }
183 EXPORT_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 */
qcom_smem_state_unregister(struct qcom_smem_state * state)189 void qcom_smem_state_unregister(struct qcom_smem_state *state)
190 {
191 state->orphan = true;
192 qcom_smem_state_put(state);
193 }
194 EXPORT_SYMBOL_GPL(qcom_smem_state_unregister);
195