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dtbocfg.c
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dtbocfg.c
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/*********************************************************************************
*
* Copyright (C) 2016-2019 Ichiro Kawazome
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
********************************************************************************/
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_fdt.h>
#include <linux/configfs.h>
#include <linux/types.h>
#include <linux/stat.h>
#include <linux/limits.h>
#include <linux/file.h>
#include <linux/version.h>
/**
* Device Tree Overlay Item Structure
*/
struct dtbocfg_overlay_item {
struct config_item item;
#if (LINUX_VERSION_CODE < 0x041100)
struct device_node* node;
#endif
int id;
void* dtbo;
int dtbo_size;
};
/**
* dtbocfg_overlay_create() - Create Device Tree Overlay
* @overlay: Pointer to Device Tree Overlay Item
* return Success(0) or Error Status.
*/
static int dtbocfg_overlay_item_create(struct dtbocfg_overlay_item *overlay)
{
int ret_val;
#if (LINUX_VERSION_CODE >= 0x041100)
{
int ovcs_id = 0;
ret_val = of_overlay_fdt_apply(overlay->dtbo,overlay->dtbo_size, &ovcs_id);
if (ret_val != 0) {
pr_err("%s: Failed to apply overlay (ret_val=%d)\n", __func__, ret_val);
goto failed;
}
overlay->id = ovcs_id;
pr_debug("%s: apply OK(id=%d)\n", __func__, ovcs_id);
}
#else
#if (LINUX_VERSION_CODE >= 0x040700)
of_fdt_unflatten_tree(overlay->dtbo, NULL, &overlay->node);
#else
of_fdt_unflatten_tree(overlay->dtbo, &overlay->node);
#endif
if (overlay->node == NULL) {
pr_err("%s: failed to unflatten tree\n", __func__);
ret_val = -EINVAL;
goto failed;
}
pr_debug("%s: unflattened OK\n", __func__);
#if (LINUX_VERSION_CODE >= 0x040F00)
{
int ovcs_id = 0;
ret_val = of_overlay_apply(overlay->node, &ovcs_id);
if (ret_val != 0) {
pr_err("%s: Failed to apply overlay (ret_val=%d)\n", __func__, ret_val);
goto failed;
}
overlay->id = ovcs_id;
pr_debug("%s: apply OK(id=%d)\n", __func__, ovcs_id);
}
#else
{
of_node_set_flag(overlay->node, OF_DETACHED);
ret_val = of_resolve_phandles(overlay->node);
if (ret_val != 0) {
pr_err("%s: Failed to resolve tree\n", __func__);
goto failed;
}
pr_debug("%s: resolved OK\n", __func__);
ret_val = of_overlay_create(overlay->node);
if (ret_val < 0) {
pr_err("%s: Failed to create overlay (ret_val=%d)\n", __func__, ret_val);
goto failed;
}
overlay->id = ret_val;
}
#endif
#endif
pr_debug("%s: create OK\n", __func__);
return 0;
failed:
return ret_val;
}
/**
* dtbocfg_overlay_item_release() - Relase Device Tree Overlay
* @overlay: Pointer to Device Tree Overlay Item
* return none
*/
static void dtbocfg_overlay_item_release(struct dtbocfg_overlay_item *overlay)
{
if (overlay->id >= 0) {
#if (LINUX_VERSION_CODE >= 0x040F00)
of_overlay_remove(&overlay->id);
#else
of_overlay_destroy(overlay->id);
#endif
overlay->id = -1;
}
}
/**
* container_of_dtbocfg_overlay_item() - Get Device Tree Overlay Item Pointer from Configuration Item
* @item: Pointer to Configuration Item
* return Pointer to Device Tree Overlay Item
*/
static inline struct dtbocfg_overlay_item* container_of_dtbocfg_overlay_item(struct config_item *item)
{
return item ? container_of(item, struct dtbocfg_overlay_item, item) : NULL;
}
/**
* dtbocfg_overlay_item_status_store() - Set Status Attibute
* @item: Pointer to Configuration Item
* @page: Pointer to Value Buffer
* @count: Size of Value Buffer Size
* return Stored Size or Error Status.
*/
static ssize_t dtbocfg_overlay_item_status_store(struct config_item *item, const char *buf, size_t count)
{
struct dtbocfg_overlay_item *overlay = container_of_dtbocfg_overlay_item(item);
ssize_t status;
unsigned long value;
if (0 != (status = kstrtoul(buf, 10, &value))) {
goto failed;
}
if (value == 0) {
if (overlay->id >= 0) {
dtbocfg_overlay_item_release(overlay);
}
} else {
if (overlay->id < 0) {
dtbocfg_overlay_item_create(overlay);
}
}
return count;
failed:
return -EPERM;
}
/**
* dtbocfg_overlay_item_status_show() - Show Status Attibute
* @item : Pointer to Configuration Item
* @page : Pointer to Value for Store
* return String Size or Error Status.
*/
static ssize_t dtbocfg_overlay_item_status_show(struct config_item *item, char *page)
{
struct dtbocfg_overlay_item *overlay = container_of_dtbocfg_overlay_item(item);
return sprintf(page, "%d\n", overlay->id >= 0 ? 1 : 0);
}
/**
* dtbocfg_overlay_item_dtbo_store() - Store Device Tree Blob to Configuration Item
* @item : Pointer to Configuration Item
* @page : Pointer to Value Buffer
* @count: Size of Value Buffer
* return Stored Size or Error Status.
*/
static ssize_t dtbocfg_overlay_item_dtbo_store(struct config_item *item, const char *buf, size_t count)
{
struct dtbocfg_overlay_item *overlay = container_of_dtbocfg_overlay_item(item);
if (overlay->dtbo_size > 0) {
if (overlay->id >= 0) {
return -EPERM;
}
kfree(overlay->dtbo);
overlay->dtbo = NULL;
overlay->dtbo_size = 0;
}
overlay->dtbo = kmemdup(buf, count, GFP_KERNEL);
if (overlay->dtbo == NULL) {
overlay->dtbo_size = 0;
return -ENOMEM;
} else {
overlay->dtbo_size = count;
return count;
}
}
/**
* dtbocfg_overlay_item_dtbo_show() - Read Device Tree Blob from Configuration Item
* @item : Pointer to Configuration Item
* @page : Pointer to Value for Store
* return Read Size
*/
static ssize_t dtbocfg_overlay_item_dtbo_show(struct config_item *item, char *buf)
{
struct dtbocfg_overlay_item *overlay = container_of_dtbocfg_overlay_item(item);
if (overlay->dtbo == NULL)
return 0;
if (overlay->dtbo_size > PAGE_SIZE)
return -EINVAL;
if (buf != NULL)
memcpy(buf, overlay->dtbo, overlay->dtbo_size);
return overlay->dtbo_size;
}
/**
* Device Tree Blob Overlay Attribute Structure
*/
CONFIGFS_ATTR(dtbocfg_overlay_item_, dtbo );
CONFIGFS_ATTR(dtbocfg_overlay_item_, status);
static struct configfs_attribute *dtbocfg_overlay_attrs[] = {
&dtbocfg_overlay_item_attr_status,
&dtbocfg_overlay_item_attr_dtbo,
NULL,
};
/**
* dtbocfg_overlay_release() - Release Device Tree Overlay Item
* @item : Pointer to Configuration Item
* Return None
*/
static void dtbocfg_overlay_release(struct config_item *item)
{
struct dtbocfg_overlay_item *overlay = container_of_dtbocfg_overlay_item(item);
pr_debug("%s\n", __func__);
dtbocfg_overlay_item_release(overlay);
if (overlay->dtbo) {
kfree(overlay->dtbo);
overlay->dtbo = NULL;
overlay->dtbo_size = 0;
}
kfree(overlay);
}
/**
* Device Tree Blob Overlay Item Structure
*/
static struct configfs_item_operations dtbocfg_overlay_item_ops = {
.release = dtbocfg_overlay_release,
};
static struct config_item_type dtbocfg_overlay_item_type = {
.ct_item_ops = &dtbocfg_overlay_item_ops,
.ct_attrs = dtbocfg_overlay_attrs,
.ct_owner = THIS_MODULE,
};
/**
* dtbocfg_overlay_group_make_item() - Make Device Tree Overlay Group Item
* @group: Pointer to Configuration Group
* @name : Pointer to Group Name
* Return Pointer to Device Tree Overlay Group Item
*/
static struct config_item *dtbocfg_overlay_group_make_item(struct config_group *group, const char *name)
{
struct dtbocfg_overlay_item *overlay;
pr_debug("%s\n", __func__);
overlay = kzalloc(sizeof(*overlay), GFP_KERNEL);
if (!overlay)
return ERR_PTR(-ENOMEM);
overlay->id = -1;
overlay->dtbo = NULL;
overlay->dtbo_size = 0;
config_item_init_type_name(&overlay->item, name, &dtbocfg_overlay_item_type);
return &overlay->item;
}
/**
* dtbocfg_overlay_group_drop_item() - Drop Device Tree Overlay Group Item
* @group: Pointer to Configuration Group
* @item : Pointer to Device Tree Overlay Group Item
*/
static void dtbocfg_overlay_group_drop_item(struct config_group *group, struct config_item *item)
{
struct dtbocfg_overlay_item *overlay = container_of_dtbocfg_overlay_item(item);
pr_debug("%s\n", __func__);
config_item_put(&overlay->item);
}
/**
* Device Tree Blob Overlay Sub Group Structures
*/
static struct configfs_group_operations dtbocfg_overlays_ops = {
.make_item = dtbocfg_overlay_group_make_item,
.drop_item = dtbocfg_overlay_group_drop_item,
};
static struct config_item_type dtbocfg_overlays_type = {
.ct_group_ops = &dtbocfg_overlays_ops,
.ct_owner = THIS_MODULE,
};
static struct config_group dtbocfg_overlay_group;
/**
* Device Tree Blob Overlay Root Sub System Structures
*/
static struct configfs_group_operations dtbocfg_root_ops = {
/* empty - we don't allow anything to be created */
};
static struct config_item_type dtbocfg_root_type = {
.ct_group_ops = &dtbocfg_root_ops,
.ct_owner = THIS_MODULE,
};
static struct configfs_subsystem dtbocfg_root_subsys = {
.su_group = {
.cg_item = {
.ci_namebuf = "device-tree",
.ci_type = &dtbocfg_root_type,
},
},
.su_mutex = __MUTEX_INITIALIZER(dtbocfg_root_subsys.su_mutex),
};
/**
* dtbocfg_module_init()
*/
static int __init dtbocfg_module_init(void)
{
int retval = 0;
pr_info("%s\n", __func__);
config_group_init(&dtbocfg_root_subsys.su_group);
config_group_init_type_name(&dtbocfg_overlay_group, "overlays", &dtbocfg_overlays_type);
retval = configfs_register_subsystem(&dtbocfg_root_subsys);
if (retval != 0) {
pr_err( "%s: couldn't register subsys\n", __func__);
goto register_subsystem_failed;
}
retval = configfs_register_group(&dtbocfg_root_subsys.su_group, &dtbocfg_overlay_group);
if (retval != 0) {
pr_err( "%s: couldn't register group\n", __func__);
goto register_group_failed;
}
pr_info("%s: OK\n", __func__);
return 0;
register_group_failed:
configfs_unregister_subsystem(&dtbocfg_root_subsys);
register_subsystem_failed:
return retval;
}
/**
* dtbocfg_module_exit()
*/
static void __exit dtbocfg_module_exit(void)
{
configfs_unregister_group(&dtbocfg_overlay_group);
configfs_unregister_subsystem(&dtbocfg_root_subsys);
}
module_init(dtbocfg_module_init);
module_exit(dtbocfg_module_exit);
MODULE_AUTHOR("ikwzm");
MODULE_DESCRIPTION("Device Tree Overlay Configuration File System");
MODULE_LICENSE("Dual BSD/GPL");