mirror of https://gitee.com/openkylin/linux.git
202 lines
4.9 KiB
C
202 lines
4.9 KiB
C
/*
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* Copyright (c) 2015, Sony Mobile Communications Inc.
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* Copyright (c) 2012-2013, The Linux Foundation. All rights reserved.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 and
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* only version 2 as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*/
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#include <linux/device.h>
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#include <linux/list.h>
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#include <linux/module.h>
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#include <linux/of.h>
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#include <linux/slab.h>
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#include <linux/soc/qcom/smem_state.h>
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static LIST_HEAD(smem_states);
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static DEFINE_MUTEX(list_lock);
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/**
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* struct qcom_smem_state - state context
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* @refcount: refcount for the state
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* @orphan: boolean indicator that this state has been unregistered
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* @list: entry in smem_states list
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* @of_node: of_node to use for matching the state in DT
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* @priv: implementation private data
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* @ops: ops for the state
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*/
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struct qcom_smem_state {
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struct kref refcount;
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bool orphan;
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struct list_head list;
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struct device_node *of_node;
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void *priv;
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struct qcom_smem_state_ops ops;
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};
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/**
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* qcom_smem_state_update_bits() - update the masked bits in state with value
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* @state: state handle acquired by calling qcom_smem_state_get()
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* @mask: bit mask for the change
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* @value: new value for the masked bits
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*
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* Returns 0 on success, otherwise negative errno.
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*/
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int qcom_smem_state_update_bits(struct qcom_smem_state *state,
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u32 mask,
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u32 value)
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{
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if (state->orphan)
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return -ENXIO;
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if (!state->ops.update_bits)
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return -ENOTSUPP;
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return state->ops.update_bits(state->priv, mask, value);
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}
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EXPORT_SYMBOL_GPL(qcom_smem_state_update_bits);
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static struct qcom_smem_state *of_node_to_state(struct device_node *np)
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{
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struct qcom_smem_state *state;
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mutex_lock(&list_lock);
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list_for_each_entry(state, &smem_states, list) {
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if (state->of_node == np) {
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kref_get(&state->refcount);
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goto unlock;
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}
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}
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state = ERR_PTR(-EPROBE_DEFER);
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unlock:
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mutex_unlock(&list_lock);
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return state;
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}
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/**
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* qcom_smem_state_get() - acquire handle to a state
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* @dev: client device pointer
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* @con_id: name of the state to lookup
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* @bit: flags from the state reference, indicating which bit's affected
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*
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* Returns handle to the state, or ERR_PTR(). qcom_smem_state_put() must be
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* called to release the returned state handle.
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*/
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struct qcom_smem_state *qcom_smem_state_get(struct device *dev,
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const char *con_id,
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unsigned *bit)
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{
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struct qcom_smem_state *state;
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struct of_phandle_args args;
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int index = 0;
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int ret;
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if (con_id) {
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index = of_property_match_string(dev->of_node,
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"qcom,smem-state-names",
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con_id);
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if (index < 0) {
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dev_err(dev, "missing qcom,smem-state-names\n");
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return ERR_PTR(index);
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}
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}
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ret = of_parse_phandle_with_args(dev->of_node,
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"qcom,smem-states",
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"#qcom,smem-state-cells",
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index,
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&args);
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if (ret) {
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dev_err(dev, "failed to parse qcom,smem-states property\n");
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return ERR_PTR(ret);
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}
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if (args.args_count != 1) {
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dev_err(dev, "invalid #qcom,smem-state-cells\n");
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return ERR_PTR(-EINVAL);
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}
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state = of_node_to_state(args.np);
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if (IS_ERR(state))
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goto put;
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*bit = args.args[0];
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put:
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of_node_put(args.np);
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return state;
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}
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EXPORT_SYMBOL_GPL(qcom_smem_state_get);
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static void qcom_smem_state_release(struct kref *ref)
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{
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struct qcom_smem_state *state = container_of(ref, struct qcom_smem_state, refcount);
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list_del(&state->list);
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kfree(state);
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}
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/**
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* qcom_smem_state_put() - release state handle
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* @state: state handle to be released
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*/
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void qcom_smem_state_put(struct qcom_smem_state *state)
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{
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mutex_lock(&list_lock);
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kref_put(&state->refcount, qcom_smem_state_release);
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mutex_unlock(&list_lock);
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}
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EXPORT_SYMBOL_GPL(qcom_smem_state_put);
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/**
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* qcom_smem_state_register() - register a new state
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* @of_node: of_node used for matching client lookups
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* @ops: implementation ops
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* @priv: implementation specific private data
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*/
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struct qcom_smem_state *qcom_smem_state_register(struct device_node *of_node,
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const struct qcom_smem_state_ops *ops,
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void *priv)
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{
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struct qcom_smem_state *state;
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state = kzalloc(sizeof(*state), GFP_KERNEL);
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if (!state)
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return ERR_PTR(-ENOMEM);
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kref_init(&state->refcount);
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state->of_node = of_node;
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state->ops = *ops;
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state->priv = priv;
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mutex_lock(&list_lock);
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list_add(&state->list, &smem_states);
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mutex_unlock(&list_lock);
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return state;
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}
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EXPORT_SYMBOL_GPL(qcom_smem_state_register);
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/**
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* qcom_smem_state_unregister() - unregister a registered state
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* @state: state handle to be unregistered
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*/
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void qcom_smem_state_unregister(struct qcom_smem_state *state)
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{
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state->orphan = true;
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qcom_smem_state_put(state);
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}
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EXPORT_SYMBOL_GPL(qcom_smem_state_unregister);
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