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/* Copyright (c) 2014, The Linux Foundation. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 and
* only 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.
*
*/
#include <linux/module.h>
#include <linux/firmware.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/of_fdt.h>
#include <linux/cdev.h>
#include <linux/slab.h>
#include <linux/platform_device.h>
#include <linux/limits.h>
struct platform_device *pdev;
static int load_overlay(const char *dtbo_name)
{
const struct firmware *fw;
struct device_node *overlay;
struct of_overlay_info *ovinfo;
int ovinfo_cnt;
int ret;
ret = request_firmware(&fw, dtbo_name, &pdev->dev);
if (ret) {
pr_err("ovloader: request_firmware on %s failed: %d\n",
dtbo_name, ret);
return ret;
}
of_fdt_unflatten_tree((void *)fw->data, &overlay);
if (!overlay) {
pr_err("ovloader: unflatten tree failed\n");
return -EINVAL;
}
of_node_set_flag(overlay, OF_DETACHED);
ret = of_resolve(overlay);
if (ret) {
pr_err("ovloader: of_resolve failed: %d\n", ret);
return ret;
}
ret = of_build_overlay_info(overlay, &ovinfo_cnt, &ovinfo);
if (ret) {
pr_err("ovloader: of_build_overlay_info failed: %d\n", ret);
return ret;
}
ret = of_overlay(ovinfo_cnt, ovinfo);
if (ret) {
pr_err("ovloader: of_overlay failed: %d\n", ret);
return ret;
}
pr_info("ovloader: successfully loaded overlay %s\n", dtbo_name);
return ret;
}
static ssize_t ovloader_set_load(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t size)
{
int ret;
char *filename;
char *newline;
if (size < 1 || size > NAME_MAX + 1)
return -EINVAL;
filename = kstrndup(buf, size, GFP_KERNEL);
if (!filename)
return -ENOMEM;
/* Drop trailing newline introduced by userspace */
newline = strrchr(filename, '\n');
if (newline)
*newline = '\0';
ret = load_overlay(filename);
kfree(filename);
if (ret)
return ret;
return size;
}
static DEVICE_ATTR(load, S_IWUSR, NULL, ovloader_set_load);
static int __init ovloader_init(void)
{
int ret;
pdev = platform_device_alloc("ovloader", 0);
if (!pdev) {
pr_err("Failed to allocate ovloader platform device\n");
goto out;
}
ret = platform_device_add(pdev);
if (ret) {
pr_err("Failed to add ovloader platform device: %d\n", ret);
goto out;
}
ret = device_create_file(&pdev->dev, &dev_attr_load);
if (ret) {
pr_err("Failed to create ovloader sysfs attribute: %d\n", ret);
goto out_device_free;
}
return 0;
out_device_free:
platform_device_put(pdev);
out:
return -ENODEV;
}
module_init(ovloader_init);
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