soc: qcom: Introduce common SMEM state machine code

This implements a common API for handling and exposing SMP2P and SMSM
state information.

Signed-off-by: Bjorn Andersson <bjorn.andersson@sonymobile.com>
Signed-off-by: Andy Gross <agross@codeaurora.org>

1 files changed, 201 insertions, 0 deletions

diff --git a/drivers/soc/qcom/smem_state.c b/drivers/soc/qcom/smem_state.c
new file mode 100644
index 000000000000..54261decb369
--- /dev/null
+++ b/drivers/soc/qcom/smem_state.c
@@ -0,0 +1,201 @@
+/*
+ * Copyright (c) 2015, Sony Mobile Communications Inc.
+ * Copyright (c) 2012-2013, The Linux Foundation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+#include <linux/device.h>
+#include <linux/list.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/slab.h>
+#include <linux/soc/qcom/smem_state.h>
+
+static LIST_HEAD(smem_states);
+static DEFINE_MUTEX(list_lock);
+
+/**
+ * struct qcom_smem_state - state context
+ * @refcount:	refcount for the state
+ * @orphan:	boolean indicator that this state has been unregistered
+ * @list:	entry in smem_states list
+ * @of_node:	of_node to use for matching the state in DT
+ * @priv:	implementation private data
+ * @ops:	ops for the state
+ */
+struct qcom_smem_state {
+	struct kref refcount;
+	bool orphan;
+
+	struct list_head list;
+	struct device_node *of_node;
+
+	void *priv;
+
+	struct qcom_smem_state_ops ops;
+};
+
+/**
+ * qcom_smem_state_update_bits() - update the masked bits in state with value
+ * @state:	state handle acquired by calling qcom_smem_state_get()
+ * @mask:	bit mask for the change
+ * @value:	new value for the masked bits
+ *
+ * Returns 0 on success, otherwise negative errno.
+ */
+int qcom_smem_state_update_bits(struct qcom_smem_state *state,
+				u32 mask,
+				u32 value)
+{
+	if (state->orphan)
+		return -ENXIO;
+
+	if (!state->ops.update_bits)
+		return -ENOTSUPP;
+
+	return state->ops.update_bits(state->priv, mask, value);
+}
+EXPORT_SYMBOL_GPL(qcom_smem_state_update_bits);
+
+static struct qcom_smem_state *of_node_to_state(struct device_node *np)
+{
+	struct qcom_smem_state *state;
+
+	mutex_lock(&list_lock);
+
+	list_for_each_entry(state, &smem_states, list) {
+		if (state->of_node == np) {
+			kref_get(&state->refcount);
+			goto unlock;
+		}
+	}
+	state = ERR_PTR(-EPROBE_DEFER);
+
+unlock:
+	mutex_unlock(&list_lock);
+
+	return state;
+}
+
+/**
+ * qcom_smem_state_get() - acquire handle to a state
+ * @dev:	client device pointer
+ * @con_id:	name of the state to lookup
+ * @bit:	flags from the state reference, indicating which bit's affected
+ *
+ * Returns handle to the state, or ERR_PTR(). qcom_smem_state_put() must be
+ * called to release the returned state handle.
+ */
+struct qcom_smem_state *qcom_smem_state_get(struct device *dev,
+					    const char *con_id,
+					    unsigned *bit)
+{
+	struct qcom_smem_state *state;
+	struct of_phandle_args args;
+	int index = 0;
+	int ret;
+
+	if (con_id) {
+		index = of_property_match_string(dev->of_node,
+						 "qcom,state-names",
+						 con_id);
+		if (index < 0) {
+			dev_err(dev, "missing qcom,state-names\n");
+			return ERR_PTR(index);
+		}
+	}
+
+	ret = of_parse_phandle_with_args(dev->of_node,
+					 "qcom,state",
+					 "#qcom,state-cells",
+					 index,
+					 &args);
+	if (ret) {
+		dev_err(dev, "failed to parse qcom,state property\n");
+		return ERR_PTR(ret);
+	}
+
+	if (args.args_count != 1) {
+		dev_err(dev, "invalid #qcom,state-cells\n");
+		return ERR_PTR(-EINVAL);
+	}
+
+	state = of_node_to_state(args.np);
+	if (IS_ERR(state))
+		goto put;
+
+	*bit = args.args[0];
+
+put:
+	of_node_put(args.np);
+	return state;
+}
+EXPORT_SYMBOL_GPL(qcom_smem_state_get);
+
+static void qcom_smem_state_release(struct kref *ref)
+{
+	struct qcom_smem_state *state = container_of(ref, struct qcom_smem_state, refcount);
+
+	list_del(&state->list);
+	kfree(state);
+}
+
+/**
+ * qcom_smem_state_put() - release state handle
+ * @state:	state handle to be released
+ */
+void qcom_smem_state_put(struct qcom_smem_state *state)
+{
+	mutex_lock(&list_lock);
+	kref_put(&state->refcount, qcom_smem_state_release);
+	mutex_unlock(&list_lock);
+}
+EXPORT_SYMBOL_GPL(qcom_smem_state_put);
+
+/**
+ * qcom_smem_state_register() - register a new state
+ * @of_node:	of_node used for matching client lookups
+ * @ops:	implementation ops
+ * @priv:	implementation specific private data
+ */
+struct qcom_smem_state *qcom_smem_state_register(struct device_node *of_node,
+						 const struct qcom_smem_state_ops *ops,
+						 void *priv)
+{
+	struct qcom_smem_state *state;
+
+	state = kzalloc(sizeof(*state), GFP_KERNEL);
+	if (!state)
+		return ERR_PTR(-ENOMEM);
+
+	kref_init(&state->refcount);
+
+	state->of_node = of_node;
+	state->ops = *ops;
+	state->priv = priv;
+
+	mutex_lock(&list_lock);
+	list_add(&state->list, &smem_states);
+	mutex_unlock(&list_lock);
+
+	return state;
+}
+EXPORT_SYMBOL_GPL(qcom_smem_state_register);
+
+/**
+ * qcom_smem_state_unregister() - unregister a registered state
+ * @state:	state handle to be unregistered
+ */
+void qcom_smem_state_unregister(struct qcom_smem_state *state)
+{
+	state->orphan = true;
+	qcom_smem_state_put(state);
+}
+EXPORT_SYMBOL_GPL(qcom_smem_state_unregister);