esoc: Add support for client notifications

Allow clients to register for external soc events.

Change-Id: If96ec725ecddfb548d7e680b09bfd68be573c11c
Signed-off-by: Hanumant Singh <hanumant@codeaurora.org>

Documentation/devicetree/bindings/esoc/esoc_client.txt

@@ -0,0 +1,58 @@
+== Introduction ==
+
+In case of multiple external socs each exposing more than one interface to a
+primary SOC, it is possible for the different interface drivers/clients to
+expect notifications regarding the state of the external soc that they are
+interested in. In some cases clients may need notifications of the status of
+multiple external socs. The bindings referred to below enable a client device
+to register for notifications from multiple external socs.
+
+== Esoc client devices ==
+
+For each esoc client device, every external soc that it is associated with, is
+assigned an integer id. These ids start at 0 and are contiguous. Each id
+represents a unique external soc. Each external soc is additionally assigned a
+name. An additional property is used to spcify the names. A mapping is
+performed from the name to the id.
+
+Required properties:
+esoc-0:		A phandle pointing to the esoc node that the esoc client is
+		interested in.
+
+esoc-names:	A list of string names for all the esocs that a given client
+		is interested in. Must have atleast one name corresponding to
+		esoc-0.
+
+Optional properties:
+esoc-1:		A phandle to the external soc, mapping to the second name in
+		esoc-names.
+...
+esoc-n:		A phandle to the nth external soc mapping to the nth name in
+		the esoc-names
+
+== Example ==
+
+esoc_a {
+	compatible = "esoc_mdm";
+	....
+	...
+	..
+};
+
+esoc_b {
+	compatible = "esoc_wlan";
+	..
+	..
+};
+
+pcie@0x0001 {
+	compatible = "esoc-pcie-client"
+	....
+	..
+	..
+	esoc-names = "mdm", "wlan";
+	esoc-0 = <&esoc_a>;
+	esoc-1 = <&esoc_b>;
+	..
+	..
+};

drivers/esoc/Kconfig

@@ -19,6 +19,15 @@ config ESOC_DEV
 	  for the external soc. It can receive event notifications from the
 	  control link.
 
+config ESOC_CLIENT
+	bool "ESOC client interface"
+	depends on OF
+	help
+	  Say yes here to enable client interface for external socs.
+	  Clients can specify the external soc that they are interested in
+	  by using device tree phandles. Based on this, clients can register
+	  for notifications from a specific soc.
+
 config ESOC_DEBUG
 	bool "ESOC debug support"
 	help

drivers/esoc/Makefile

@@ -3,5 +3,6 @@
 ccflags-$(CONFIG_ESOC_DEBUG)	:= -DDEBUG
 obj-$(CONFIG_ESOC)	+= esoc_bus.o
 obj-$(CONFIG_ESOC_DEV)	+= esoc_dev.o
+obj-$(CONFIG_ESOC_CLIENT)	+= esoc_client.o
 obj-$(CONFIG_ESOC_MDM_4x)	+= esoc-mdm-4x.o
 obj-$(CONFIG_ESOC_MDM_DRV)	+= esoc-mdm-drv.o

drivers/esoc/esoc.h

@@ -57,6 +57,7 @@ struct esoc_eng {
  * @compat_data: compat data of esoc driver.
  * @subsys_desc: descriptor for subsystem restart
  * @subsys_dev: ssr device handle.
+ * @np: device tree node for esoc_clink.
  */
 struct esoc_clink {
 	const char *name;
@@ -73,6 +74,7 @@ struct esoc_clink {
 	void *compat_data;
 	struct subsys_desc subsys;
 	struct subsys_device *subsys_dev;
+	struct device_node *np;
 };
 
 /**
@@ -125,6 +127,7 @@ int esoc_dev_init(void);
 void esoc_clink_unregister(struct esoc_clink *esoc_dev);
 int esoc_clink_register(struct esoc_clink *esoc_dev);
 struct esoc_clink *get_esoc_clink(int id);
+struct esoc_clink *get_esoc_clink_by_node(struct device_node *node);
 void put_esoc_clink(struct esoc_clink *esoc_clink);
 void *get_esoc_clink_data(struct esoc_clink *esoc);
 void set_esoc_clink_data(struct esoc_clink *esoc, void *data);
@@ -147,4 +150,14 @@ void *esoc_get_drv_data(struct esoc_clink *esoc_clink);
 int esoc_clink_register_ssr(struct esoc_clink *esoc_clink);
 int esoc_clink_request_ssr(struct esoc_clink *esoc_clink);
 void esoc_clink_unregister_ssr(struct esoc_clink *esoc_clink);
+/* client notification */
+#ifdef CONFIG_ESOC_CLIENT
+void notify_esoc_clients(struct esoc_clink *esoc_clink, unsigned long evt);
+#else
+static inline void notify_esoc_clients(struct esoc_clink *esoc_clink,
+							unsigned long evt)
+{
+	return;
+}
+#endif
 #endif

drivers/esoc/esoc_bus.c

@@ -101,6 +101,19 @@ static int esoc_clink_match_id(struct device *dev, void *id)
 	return 0;
 }
 
+static int esoc_clink_match_node(struct device *dev, void *id)
+{
+	struct esoc_clink *esoc_clink = to_esoc_clink(dev);
+	struct device_node *node = id;
+
+	if (esoc_clink->np == node) {
+		if (!try_module_get(esoc_clink->owner))
+			return 0;
+		return 1;
+	}
+	return 0;
+}
+
 void esoc_for_each_dev(void *data, int (*fn)(struct device *dev, void *))
 {
 	int ret;
@@ -123,6 +136,19 @@ struct esoc_clink *get_esoc_clink(int id)
 }
 EXPORT_SYMBOL(get_esoc_clink);
 
+struct esoc_clink *get_esoc_clink_by_node(struct device_node *node)
+{
+	struct esoc_clink *esoc_clink;
+	struct device *dev;
+
+	dev = bus_find_device(&esoc_bus_type, NULL, node,
+						esoc_clink_match_node);
+	if (IS_ERR(dev))
+		return NULL;
+	esoc_clink = to_esoc_clink(dev);
+	return esoc_clink;
+}
+
 void put_esoc_clink(struct esoc_clink *esoc_clink)
 {
 	module_put(esoc_clink->owner);
@@ -176,6 +202,7 @@ void esoc_clink_evt_notify(enum esoc_evt evt, struct esoc_clink *esoc_clink)
 	unsigned long flags;
 
 	spin_lock_irqsave(&esoc_clink->notify_lock, flags);
+	notify_esoc_clients(esoc_clink, evt);
 	if (esoc_clink->req_eng && esoc_clink->req_eng->handle_clink_evt)
 		esoc_clink->req_eng->handle_clink_evt(evt, esoc_clink->req_eng);
 	if (esoc_clink->cmd_eng && esoc_clink->cmd_eng->handle_clink_evt)

drivers/esoc/esoc_client.c

@@ -0,0 +1,115 @@
+/* Copyright (c) 2014, 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/esoc_client.h>
+#include <linux/of.h>
+#include <linux/spinlock.h>
+#include "esoc.h"
+
+static DEFINE_SPINLOCK(notify_lock);
+static ATOMIC_NOTIFIER_HEAD(client_notify);
+
+static void devm_esoc_desc_release(struct device *dev, void *res)
+{
+	struct esoc_desc *esoc_desc = res;
+	kfree(esoc_desc->name);
+	put_esoc_clink(esoc_desc->priv);
+}
+
+static int devm_esoc_desc_match(struct device *dev, void *res, void *data)
+{
+	struct esoc_desc *esoc_desc = res;
+	return esoc_desc == data;
+}
+
+struct esoc_desc *devm_register_esoc_client(struct device *dev,
+							const char *name)
+{
+	int ret, index;
+	const char *client_desc;
+	char *esoc_prop;
+	const __be32 *parp;
+	struct device_node *esoc_node;
+	struct device_node *np = dev->of_node;
+	struct esoc_clink *esoc_clink;
+	struct esoc_desc *desc;
+	char *esoc_name;
+
+	for (index = 0;; index++) {
+		esoc_prop = kasprintf(GFP_KERNEL, "esoc-%d", index);
+		parp = of_get_property(np, esoc_prop, NULL);
+		if (parp == NULL) {
+			dev_err(dev, "esoc device not present\n");
+			kfree(esoc_prop);
+			return NULL;
+		}
+		ret = of_property_read_string_index(np, "esoc-names", index,
+								&client_desc);
+		if (ret) {
+			dev_err(dev, "cannot find matching string\n");
+			kfree(esoc_prop);
+			return NULL;
+		}
+		if (strcmp(client_desc, name)) {
+			kfree(esoc_prop);
+			continue;
+		}
+		kfree(esoc_prop);
+		esoc_node = of_find_node_by_phandle(be32_to_cpup(parp));
+		esoc_clink = get_esoc_clink_by_node(esoc_node);
+		if (!esoc_clink) {
+			dev_err(dev, "matching esoc clink not present\n");
+			return NULL;
+		}
+		desc = devres_alloc(devm_esoc_desc_release,
+						sizeof(*desc), GFP_KERNEL);
+		if (!desc)
+			return ERR_PTR(-ENOMEM);
+		esoc_name = kasprintf(GFP_KERNEL, "subsys_esoc%d",
+							esoc_clink->id);
+		desc->name = esoc_name;
+		desc->priv = esoc_clink;
+		devres_add(dev, desc);
+		return desc;
+	}
+	return NULL;
+}
+EXPORT_SYMBOL(devm_register_esoc_client);
+
+void devm_unregister_esoc_client(struct device *dev,
+					struct esoc_desc *esoc_desc)
+{
+	int ret;
+
+	ret = devres_release(dev, devm_esoc_desc_release,
+				devm_esoc_desc_match, esoc_desc);
+	WARN_ON(ret);
+}
+EXPORT_SYMBOL(devm_unregister_esoc_client);
+
+int esoc_register_client_notifier(struct notifier_block *nb)
+{
+	return atomic_notifier_chain_register(&client_notify, nb);
+}
+EXPORT_SYMBOL(esoc_register_client_notifier);
+
+void notify_esoc_clients(struct esoc_clink *esoc_clink, unsigned long evt)
+{
+	unsigned int id;
+	unsigned long flags;
+
+	spin_lock_irqsave(&notify_lock, flags);
+	id = esoc_clink->id;
+	atomic_notifier_call_chain(&client_notify, evt, &id);
+	spin_unlock_irqrestore(&notify_lock, flags);
+}
+EXPORT_SYMBOL(notify_esoc_clients);

include/linux/esoc_client.h

@@ -0,0 +1,33 @@
+/* Copyright (c) 2014, 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.
+ */
+#ifndef __ESOC_CLIENT_H_
+#define __ESOC_CLIENT_H_
+
+#include <linux/esoc_ctrl.h>
+#include <linux/notifier.h>
+
+/*
+ * struct esoc_desc: Describes an external soc
+ * @name: external soc name
+ * @priv: private data for external soc
+ */
+struct esoc_desc {
+	const char *name;
+	void *priv;
+};
+
+struct esoc_desc *devm_register_esoc_client(struct device *dev,
+							const char *name);
+void devm_unregister_esoc_client(struct device *dev,
+						struct esoc_desc *esoc_desc);
+int esoc_register_client_notifier(struct notifier_block *nb);
+#endif