tegrakernel/kernel/nvidia/drivers/platform/tegra/bcp.c

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2022-02-16 09:13:02 -06:00
/*
* Copyright (c) 2016, Harman Becker. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope 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.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/kobject.h>
#include <linux/sysfs.h>
#include <linux/string.h>
#include <linux/io.h>
#include "tegra_bootloader_debug.h"
static void *tegra_bl_mapped_boot_cfg_start;
static ssize_t bcp_data_read(struct file *filp, struct kobject *kobj,
struct bin_attribute *bin_attr,
char *buf, loff_t off, size_t count)
{
uint8_t *data = (uint8_t *) tegra_bl_mapped_boot_cfg_start;
/* read from the reserved memory */
memcpy(buf, data + off, count);
return count;
}
static struct bin_attribute bcp_attr_data = {
.attr = {
.name = "boot_cfg",
.mode = 0444,
},
.size = 0,
.read = bcp_data_read,
.write = NULL,
};
static __init int bcp_init(void)
{
int ret = 0;
void __iomem *ptr_bl_boot_cfg_start = NULL;
tegra_bl_mapped_boot_cfg_start = NULL;
/* If the following variables are not set then we don't have BCP data */
if (!tegra_bl_bcp_size || !tegra_bl_bcp_start)
return -ENXIO;
tegra_bl_mapped_boot_cfg_start = phys_to_virt(tegra_bl_bcp_start);
if (!pfn_valid(__phys_to_pfn(tegra_bl_bcp_start))) {
ptr_bl_boot_cfg_start =
ioremap(tegra_bl_bcp_start, tegra_bl_bcp_size);
WARN_ON(!ptr_bl_boot_cfg_start);
if (!ptr_bl_boot_cfg_start) {
pr_error("%s: Failed to map tegra_bl_prof_start %08x\n",
__func__, (unsigned int)tegra_bl_bcp_start);
ret = -ENXIO;
goto out_err;
}
tegra_bl_mapped_boot_cfg_start = ptr_bl_boot_cfg_start;
}
bcp_attr_data.size = tegra_bl_bcp_size;
ret = sysfs_create_bin_file(kernel_kobj, &bcp_attr_data);
if (ret) {
pr_error("%s: sysfs_create_bin_file failed\n",
__func__);
goto out_err;
}
return ret;
out_err:
if (ptr_bl_boot_cfg_start)
iounmap(ptr_bl_boot_cfg_start);
return ret;
}
static void __exit bcp_exit(void)
{
if (tegra_bl_mapped_boot_cfg_start)
iounmap(tegra_bl_mapped_boot_cfg_start);
sysfs_remove_bin_file(kernel_kobj, &bcp_attr_data);
}
module_init(bcp_init);
module_exit(bcp_exit);
MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("Driver to expose BCP data to user space");
MODULE_AUTHOR("Lukasz Taborowski <lukasz.taborowski@harman.com>");