// SPDX-License-Identifier: GPL-2.0
/*
* FPGA Bridge Framework Driver
*
* Copyright (C) 2013-2016 Altera Corporation, All Rights Reserved.
* Copyright (C) 2017 Intel Corporation
*/
#include <linux/fpga/fpga-bridge.h>
#include <linux/idr.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of_platform.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
static DEFINE_IDA(fpga_bridge_ida);
static const struct class fpga_bridge_class;
/* Lock for adding/removing bridges to linked lists*/
static DEFINE_SPINLOCK(bridge_list_lock);
/**
* fpga_bridge_enable - Enable transactions on the bridge
*
* @bridge: FPGA bridge
*
* Return: 0 for success, error code otherwise.
*/
int fpga_bridge_enable(struct fpga_bridge *bridge)
{
dev_dbg(&bridge->dev, "enable\n");
if (bridge->br_ops->enable_set)
return bridge->br_ops->enable_set(bridge, 1);
return 0;
}
EXPORT_SYMBOL_GPL(fpga_bridge_enable);
/**
* fpga_bridge_disable - Disable transactions on the bridge
*
* @bridge: FPGA bridge
*
* Return: 0 for success, error code otherwise.
*/
int fpga_bridge_disable(struct fpga_bridge *bridge)
{
dev_dbg(&bridge->dev, "disable\n");
if (bridge->br_ops->enable_set)
return bridge->br_ops->enable_set(bridge, 0);
return 0;
}
EXPORT_SYMBOL_GPL(fpga_bridge_disable);
static struct fpga_bridge *__fpga_bridge_get(struct device *bridge_dev,
struct fpga_image_info *info)
{
struct fpga_bridge *bridge;
bridge = to_fpga_bridge(bridge_dev);
bridge->info = info;
if (!mutex_trylock(&bridge->mutex))
return ERR_PTR(-EBUSY);
if (!try_module_get(bridge->br_ops_owner)) {
mutex_unlock(&bridge->mutex);
return ERR_PTR(-ENODEV);
}
dev_dbg(&bridge->dev, "get\n");
return bridge;
}
/**
* of_fpga_bridge_get - get an exclusive reference to an fpga bridge
*
* @np: node pointer of an FPGA bridge.
* @info: fpga image specific information.
*
* Return:
* * fpga_bridge struct pointer if successful.
* * -EBUSY if someone already has a reference to the bridge.
* * -ENODEV if @np is not an FPGA Bridge or can't take parent driver refcount.
*/
struct fpga_bridge *of_fpga_bridge_get(struct device_node *np,
struct fpga_image_info *info)
{
struct fpga_bridge *bridge;
struct device *bridge_dev;
bridge_dev = class_find_device_by_of_node(&fpga_bridge_class, np);
if (!bridge_dev)
return ERR_PTR(-ENODEV);
bridge = __fpga_bridge_get(bridge_dev, info);
if (IS_ERR(bridge))
put_device(bridge_dev);
return bridge;
}
EXPORT_SYMBOL_GPL(of_fpga_bridge_get);
static int fpga_bridge_dev_match(struct device *dev, const void *data)
{
return dev->parent == data;
}
/**
* fpga_bridge_get - get an exclusive reference to an fpga bridge
* @dev: parent device that fpga bridge was registered with
* @info: fpga image specific information
*
* Given a device, get an exclusive reference to an fpga bridge.
*
* Return: fpga bridge struct or IS_ERR() condition containing error code.
*/
struct fpga_bridge *fpga_bridge_get(struct device *dev,
struct fpga_image_info *info)
{
struct fpga_bridge *bridge;
struct device *bridge_dev;
bridge_dev = class_find_device(&fpga_bridge_class, NULL, dev,
fpga_bridge_dev_match);
if (!bridge_dev)
return ERR_PTR(-ENODEV);
bridge = __fpga_bridge_get(bridge_dev, info);
if (IS_ERR(bridge))
put_device(bridge_dev);
return bridge;
}
EXPORT_SYMBOL_GPL(fpga_bridge_get);
/**
* fpga_bridge_put - release a reference to a bridge
*
* @bridge: FPGA bridge
*/
void fpga_bridge_put(struct fpga_bridge *bridge)
{
dev_dbg(&bridge->dev, "put\n");
bridge->info = NULL;
module_put(bridge->br_ops_owner);
mutex_unlock(&bridge->mutex);
put_device(&bridge->dev);
}
EXPORT_SYMBOL_GPL(fpga_bridge_put);
/**
* fpga_bridges_enable - enable bridges in a list
* @bridge_list: list of FPGA bridges
*
* Enable each bridge in the list. If list is empty, do nothing.
*
* Return: 0 for success or empty bridge list or an error code otherwise.
*/
int fpga_bridges_enable(struct list_head *bridge_list)
{
struct fpga_bridge *bridge;
int ret;
list_for_each_entry(bridge, bridge_list, node) {
ret = fpga_bridge_enable(bridge);
if (ret)
return ret;
}
return 0;
}
EXPORT_SYMBOL_GPL(fpga_bridges_enable);
/**
* fpga_bridges_disable - disable bridges in a list
*
* @bridge_list: list of FPGA bridges
*
* Disable each bridge in the list. If list is empty, do nothing.
*
* Return: 0 for success or empty bridge list or an error code otherwise.
*/
int fpga_bridges_disable(struct list_head *bridge_list)
{
struct fpga_bridge *bridge;
int ret;
list_for_each_entry(bridge, bridge_list, node) {
ret = fpga_bridge_disable(bridge);
if (ret)
return ret;
}
return 0;
}
EXPORT_SYMBOL_GPL(fpga_bridges_disable);
/**
* fpga_bridges_put - put bridges
*
* @bridge_list: list of FPGA bridges
*
* For each bridge in the list, put the bridge and remove it from the list.
* If list is empty, do nothing.
*/
void fpga_bridges_put(struct list_head *bridge_list)
{
struct fpga_bridge *bridge, *next;
unsigned long flags;
list_for_each_entry_safe(bridge, next, bridge_list, node) {
fpga_bridge_put(bridge);
spin_lock_irqsave(&bridge_list_lock, flags);
list_del(&bridge->node);
spin_unlock_irqrestore(&bridge_list_lock, flags);
}
}
EXPORT_SYMBOL_GPL(fpga_bridges_put);
/**
* of_fpga_bridge_get_to_list - get a bridge, add it to a list
*
* @np: node pointer of an FPGA bridge
* @info: fpga image specific information
* @bridge_list: list of FPGA bridges
*
* Get an exclusive reference to the bridge and it to the list.
*
* Return: 0 for success, error code from of_fpga_bridge_get() otherwise.
*/
int of_fpga_bridge_get_to_list(struct device_node *np,
struct fpga_image_info *info,
struct list_head *bridge_list)
{
struct fpga_bridge *bridge;
unsigned long flags;
bridge = of_fpga_bridge_get(np, info);
if (IS_ERR(bridge))
return PTR_ERR(bridge);
spin_lock_irqsave(&bridge_list_lock, flags);
list_add(&bridge->node, bridge_list);
spin_unlock_irqrestore(&bridge_list_lock, flags);
return 0;
}
EXPORT_SYMBOL_GPL(of_fpga_bridge_get_to_list);
/**
* fpga_bridge_get_to_list - given device, get a bridge, add it to a list
*
* @dev: FPGA bridge device
* @info: fpga image specific information
* @bridge_list: list of FPGA bridges
*
* Get an exclusive reference to the bridge and it to the list.
*
* Return: 0 for success, error code from fpga_bridge_get() otherwise.
*/
int fpga_bridge_get_to_list(struct device *dev,
struct fpga_image_info *info,
struct list_head *bridge_list)
{
struct fpga_bridge *bridge;
unsigned long flags;
bridge = fpga_bridge_get(dev, info);
if (IS_ERR(bridge))
return PTR_ERR(bridge);
spin_lock_irqsave(&bridge_list_lock, flags);
list_add(&bridge->node, bridge_list);
spin_unlock_irqrestore(&bridge_list_lock, flags);
return 0;
}
EXPORT_SYMBOL_GPL(fpga_bridge_get_to_list);
static ssize_t name_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct fpga_bridge *bridge = to_fpga_bridge(dev);
return sprintf(buf, "%s\n", bridge->name);
}
static ssize_t state_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct fpga_bridge *bridge = to_fpga_bridge(dev);
int state = 1;
if (bridge->br_ops->enable_show) {
state = bridge->br_ops->enable_show(bridge);
if (state < 0)
return state;
}
return sysfs_emit(buf, "%s\n", state ? "enabled" : "disabled");
}
static DEVICE_ATTR_RO(name);
static DEVICE_ATTR_RO(state);
static struct attribute *fpga_bridge_attrs[] = {
&dev_attr_name.attr,
&dev_attr_state.attr,
NULL,
};
ATTRIBUTE_GROUPS(fpga_bridge);
/**
* __fpga_bridge_register - create and register an FPGA Bridge device
* @parent: FPGA bridge device from pdev
* @name: FPGA bridge name
* @br_ops: pointer to structure of fpga bridge ops
* @priv: FPGA bridge private data
* @owner: owner module containing the br_ops
*
* Return: struct fpga_bridge pointer or ERR_PTR()
*/
struct fpga_bridge *
__fpga_bridge_register(struct device *parent, const char *name,
const struct fpga_bridge_ops *br_ops,
void *priv, struct module *owner)
{
struct fpga_bridge *bridge;
int id, ret;
if (!br_ops) {
dev_err(parent, "Attempt to register without fpga_bridge_ops\n");
return ERR_PTR(-EINVAL);
}
if (!name || !strlen(name)) {
dev_err(parent, "Attempt to register with no name!\n");
return ERR_PTR(-EINVAL);
}
bridge = kzalloc(sizeof(*bridge), GFP_KERNEL);
if (!bridge)
return ERR_PTR(-ENOMEM);
id = ida_alloc(&fpga_bridge_ida, GFP_KERNEL);
if (id < 0) {
ret = id;
goto error_kfree;
}
mutex_init(&bridge->mutex);
INIT_LIST_HEAD(&bridge->node);
bridge->name = name;
bridge->br_ops = br_ops;
bridge->br_ops_owner = owner;
bridge->priv = priv;
bridge->dev.groups = br_ops->groups;
bridge->dev.class = &fpga_bridge_class;
bridge->dev.parent = parent;
bridge->dev.of_node = parent->of_node;
bridge->dev.id = id;
ret = dev_set_name(&bridge->dev, "br%d", id);
if (ret)
goto error_device;
ret = device_register(&bridge->dev);
if (ret) {
put_device(&bridge->dev);
return ERR_PTR(ret);
}
of_platform_populate(bridge->dev.of_node, NULL, NULL, &bridge->dev);
return bridge;
error_device:
ida_free(&fpga_bridge_ida, id);
error_kfree:
kfree(bridge);
return ERR_PTR(ret);
}
EXPORT_SYMBOL_GPL(__fpga_bridge_register);
/**
* fpga_bridge_unregister - unregister an FPGA bridge
*
* @bridge: FPGA bridge struct
*
* This function is intended for use in an FPGA bridge driver's remove function.
*/
void fpga_bridge_unregister(struct fpga_bridge *bridge)
{
/*
* If the low level driver provides a method for putting bridge into
* a desired state upon unregister, do it.
*/
if (bridge->br_ops->fpga_bridge_remove)
bridge->br_ops->fpga_bridge_remove(bridge);
device_unregister(&bridge->dev);
}
EXPORT_SYMBOL_GPL(fpga_bridge_unregister);
static void fpga_bridge_dev_release(struct device *dev)
{
struct fpga_bridge *bridge = to_fpga_bridge(dev);
ida_free(&fpga_bridge_ida, bridge->dev.id);
kfree(bridge);
}
static const struct class fpga_bridge_class = {
.name = "fpga_bridge",
.dev_groups = fpga_bridge_groups,
.dev_release = fpga_bridge_dev_release,
};
static int __init fpga_bridge_dev_init(void)
{
return class_register(&fpga_bridge_class);
}
static void __exit fpga_bridge_dev_exit(void)
{
class_unregister(&fpga_bridge_class);
ida_destroy(&fpga_bridge_ida);
}
MODULE_DESCRIPTION("FPGA Bridge Driver");
MODULE_AUTHOR("Alan Tull <[email protected]>");
MODULE_LICENSE("GPL v2");
subsys_initcall(fpga_bridge_dev_init);
module_exit(fpga_bridge_dev_exit);
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