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- /*
- * 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);
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