linux/drivers/mfd/vexpress-config.c

289 lines
7.3 KiB
C

/*
* 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;
}
EXPORT_SYMBOL(vexpress_config_bridge_register);
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();
}
EXPORT_SYMBOL(vexpress_config_bridge_unregister);
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;
}
EXPORT_SYMBOL(__vexpress_config_func_get);
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);
}
EXPORT_SYMBOL(vexpress_config_func_put);
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);
if (list_empty(&bridge->transactions)) {
vexpress_config_dump_trans("Executing", trans);
status = bridge->info->func_exec(trans->func->func,
trans->offset, trans->write, trans->data);
} else {
vexpress_config_dump_trans("Queuing", trans);
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;
const char *message = "Completed";
spin_lock_irqsave(&bridge->transactions_lock, flags);
trans = list_first_entry(&bridge->transactions,
struct vexpress_config_trans, list);
trans->status = status;
do {
vexpress_config_dump_trans(message, trans);
list_del(&trans->list);
complete(&trans->completion);
if (list_empty(&bridge->transactions))
break;
trans = list_first_entry(&bridge->transactions,
struct vexpress_config_trans, list);
vexpress_config_dump_trans("Executing pending", trans);
trans->status = bridge->info->func_exec(trans->func->func,
trans->offset, trans->write, trans->data);
message = "Finished pending";
} while (trans->status == VEXPRESS_CONFIG_STATUS_DONE);
spin_unlock_irqrestore(&bridge->transactions_lock, flags);
}
EXPORT_SYMBOL(vexpress_config_complete);
int vexpress_config_wait(struct vexpress_config_trans *trans)
{
wait_for_completion(&trans->completion);
return trans->status;
}
EXPORT_SYMBOL(vexpress_config_wait);
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);