1 files changed, 277 insertions, 0 deletions

diff --git a/drivers/mfd/vexpress-config.c b/drivers/mfd/vexpress-config.c
new file mode 100644
index 000000000000..fae15d880758
--- /dev/null
+++ b/drivers/mfd/vexpress-config.c
@@ -0,0 +1,277 @@
+/*
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License 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.
+ *
+ * Copyright (C) 2012 ARM Limited
+ */
+
+#define pr_fmt(fmt) "vexpress-config: " fmt
+
+#include <linux/bitops.h>
+#include <linux/completion.h>
+#include <linux/export.h>
+#include <linux/init.h>
+#include <linux/list.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/vexpress.h>
+
+
+#define VEXPRESS_CONFIG_MAX_BRIDGES 2
+
+struct vexpress_config_bridge {
+	struct device_node *node;
+	struct vexpress_config_bridge_info *info;
+	struct list_head transactions;
+	spinlock_t transactions_lock;
+} vexpress_config_bridges[VEXPRESS_CONFIG_MAX_BRIDGES];
+
+static DECLARE_BITMAP(vexpress_config_bridges_map,
+		ARRAY_SIZE(vexpress_config_bridges));
+static DEFINE_MUTEX(vexpress_config_bridges_mutex);
+
+struct vexpress_config_bridge *vexpress_config_bridge_register(
+		struct device_node *node,
+		struct vexpress_config_bridge_info *info)
+{
+	struct vexpress_config_bridge *bridge;
+	int i;
+
+	pr_debug("Registering bridge '%s'\n", info->name);
+
+	mutex_lock(&vexpress_config_bridges_mutex);
+	i = find_first_zero_bit(vexpress_config_bridges_map,
+			ARRAY_SIZE(vexpress_config_bridges));
+	if (i >= ARRAY_SIZE(vexpress_config_bridges)) {
+		pr_err("Can't register more bridges!\n");
+		mutex_unlock(&vexpress_config_bridges_mutex);
+		return NULL;
+	}
+	__set_bit(i, vexpress_config_bridges_map);
+	bridge = &vexpress_config_bridges[i];
+
+	bridge->node = node;
+	bridge->info = info;
+	INIT_LIST_HEAD(&bridge->transactions);
+	spin_lock_init(&bridge->transactions_lock);
+
+	mutex_unlock(&vexpress_config_bridges_mutex);
+
+	return bridge;
+}
+
+void vexpress_config_bridge_unregister(struct vexpress_config_bridge *bridge)
+{
+	struct vexpress_config_bridge __bridge = *bridge;
+	int i;
+
+	mutex_lock(&vexpress_config_bridges_mutex);
+	for (i = 0; i < ARRAY_SIZE(vexpress_config_bridges); i++)
+		if (&vexpress_config_bridges[i] == bridge)
+			__clear_bit(i, vexpress_config_bridges_map);
+	mutex_unlock(&vexpress_config_bridges_mutex);
+
+	WARN_ON(!list_empty(&__bridge.transactions));
+	while (!list_empty(&__bridge.transactions))
+		cpu_relax();
+}
+
+
+struct vexpress_config_func {
+	struct vexpress_config_bridge *bridge;
+	void *func;
+};
+
+struct vexpress_config_func *__vexpress_config_func_get(struct device *dev,
+		struct device_node *node)
+{
+	struct device_node *bridge_node;
+	struct vexpress_config_func *func;
+	int i;
+
+	if (WARN_ON(dev && node && dev->of_node != node))
+		return NULL;
+	if (dev && !node)
+		node = dev->of_node;
+
+	func = kzalloc(sizeof(*func), GFP_KERNEL);
+	if (!func)
+		return NULL;
+
+	bridge_node = of_node_get(node);
+	while (bridge_node) {
+		const __be32 *prop = of_get_property(bridge_node,
+				"arm,vexpress,config-bridge", NULL);
+
+		if (prop) {
+			bridge_node = of_find_node_by_phandle(
+					be32_to_cpup(prop));
+			break;
+		}
+
+		bridge_node = of_get_next_parent(bridge_node);
+	}
+
+	mutex_lock(&vexpress_config_bridges_mutex);
+	for (i = 0; i < ARRAY_SIZE(vexpress_config_bridges); i++) {
+		struct vexpress_config_bridge *bridge =
+				&vexpress_config_bridges[i];
+
+		if (test_bit(i, vexpress_config_bridges_map) &&
+				bridge->node == bridge_node) {
+			func->bridge = bridge;
+			func->func = bridge->info->func_get(dev, node);
+			break;
+		}
+	}
+	mutex_unlock(&vexpress_config_bridges_mutex);
+
+	if (!func->func) {
+		of_node_put(node);
+		kfree(func);
+		return NULL;
+	}
+
+	return func;
+}
+
+void vexpress_config_func_put(struct vexpress_config_func *func)
+{
+	func->bridge->info->func_put(func->func);
+	of_node_put(func->bridge->node);
+	kfree(func);
+}
+
+
+struct vexpress_config_trans {
+	struct vexpress_config_func *func;
+	int offset;
+	bool write;
+	u32 *data;
+	int status;
+	struct completion completion;
+	struct list_head list;
+};
+
+static void vexpress_config_dump_trans(const char *what,
+		struct vexpress_config_trans *trans)
+{
+	pr_debug("%s %s trans %p func 0x%p offset %d data 0x%x status %d\n",
+			what, trans->write ? "write" : "read", trans,
+			trans->func->func, trans->offset,
+			trans->data ? *trans->data : 0, trans->status);
+}
+
+static int vexpress_config_schedule(struct vexpress_config_trans *trans)
+{
+	int status;
+	struct vexpress_config_bridge *bridge = trans->func->bridge;
+	unsigned long flags;
+
+	init_completion(&trans->completion);
+	trans->status = -EFAULT;
+
+	spin_lock_irqsave(&bridge->transactions_lock, flags);
+
+	vexpress_config_dump_trans("Executing", trans);
+
+	if (list_empty(&bridge->transactions))
+		status = bridge->info->func_exec(trans->func->func,
+				trans->offset, trans->write, trans->data);
+	else
+		status = VEXPRESS_CONFIG_STATUS_WAIT;
+
+	switch (status) {
+	case VEXPRESS_CONFIG_STATUS_DONE:
+		vexpress_config_dump_trans("Finished", trans);
+		trans->status = status;
+		break;
+	case VEXPRESS_CONFIG_STATUS_WAIT:
+		list_add_tail(&trans->list, &bridge->transactions);
+		break;
+	}
+
+	spin_unlock_irqrestore(&bridge->transactions_lock, flags);
+
+	return status;
+}
+
+void vexpress_config_complete(struct vexpress_config_bridge *bridge,
+		int status)
+{
+	struct vexpress_config_trans *trans;
+	unsigned long flags;
+
+	spin_lock_irqsave(&bridge->transactions_lock, flags);
+
+	trans = list_first_entry(&bridge->transactions,
+			struct vexpress_config_trans, list);
+	vexpress_config_dump_trans("Completed", trans);
+
+	trans->status = status;
+	list_del(&trans->list);
+
+	if (!list_empty(&bridge->transactions)) {
+		vexpress_config_dump_trans("Pending", trans);
+
+		bridge->info->func_exec(trans->func->func, trans->offset,
+				trans->write, trans->data);
+	}
+	spin_unlock_irqrestore(&bridge->transactions_lock, flags);
+
+	complete(&trans->completion);
+}
+
+int vexpress_config_wait(struct vexpress_config_trans *trans)
+{
+	wait_for_completion(&trans->completion);
+
+	return trans->status;
+}
+
+
+int vexpress_config_read(struct vexpress_config_func *func, int offset,
+		u32 *data)
+{
+	struct vexpress_config_trans trans = {
+		.func = func,
+		.offset = offset,
+		.write = false,
+		.data = data,
+		.status = 0,
+	};
+	int status = vexpress_config_schedule(&trans);
+
+	if (status == VEXPRESS_CONFIG_STATUS_WAIT)
+		status = vexpress_config_wait(&trans);
+
+	return status;
+}
+EXPORT_SYMBOL(vexpress_config_read);
+
+int vexpress_config_write(struct vexpress_config_func *func, int offset,
+		u32 data)
+{
+	struct vexpress_config_trans trans = {
+		.func = func,
+		.offset = offset,
+		.write = true,
+		.data = &data,
+		.status = 0,
+	};
+	int status = vexpress_config_schedule(&trans);
+
+	if (status == VEXPRESS_CONFIG_STATUS_WAIT)
+		status = vexpress_config_wait(&trans);
+
+	return status;
+}
+EXPORT_SYMBOL(vexpress_config_write);