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path: root/drivers/mfd/vexpress-config.c
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Diffstat (limited to 'drivers/mfd/vexpress-config.c')
-rw-r--r--drivers/mfd/vexpress-config.c277
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 00000000000..fae15d88075
--- /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);