157 lines
4.2 KiB
C
157 lines
4.2 KiB
C
/*
|
|
* Copyright (c) 2013 Oliver Schinagl <oliver@schinagl.nl>
|
|
* http://www.linux-sunxi.org
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License as published by
|
|
* the Free Software Foundation; either version 2 of the License, or
|
|
* (at your option) any later version.
|
|
*
|
|
* 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.
|
|
*
|
|
* This driver exposes the Allwinner security ID, efuses exported in byte-
|
|
* sized chunks.
|
|
*/
|
|
|
|
#include <linux/compiler.h>
|
|
#include <linux/device.h>
|
|
#include <linux/err.h>
|
|
#include <linux/export.h>
|
|
#include <linux/fs.h>
|
|
#include <linux/io.h>
|
|
#include <linux/kernel.h>
|
|
#include <linux/kobject.h>
|
|
#include <linux/module.h>
|
|
#include <linux/of_device.h>
|
|
#include <linux/platform_device.h>
|
|
#include <linux/random.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/stat.h>
|
|
#include <linux/sysfs.h>
|
|
#include <linux/types.h>
|
|
|
|
#define DRV_NAME "sunxi-sid"
|
|
|
|
struct sunxi_sid_data {
|
|
void __iomem *reg_base;
|
|
unsigned int keysize;
|
|
};
|
|
|
|
/* We read the entire key, due to a 32 bit read alignment requirement. Since we
|
|
* want to return the requested byte, this results in somewhat slower code and
|
|
* uses 4 times more reads as needed but keeps code simpler. Since the SID is
|
|
* only very rarely probed, this is not really an issue.
|
|
*/
|
|
static u8 sunxi_sid_read_byte(const struct sunxi_sid_data *sid_data,
|
|
const unsigned int offset)
|
|
{
|
|
u32 sid_key;
|
|
|
|
if (offset >= sid_data->keysize)
|
|
return 0;
|
|
|
|
sid_key = ioread32be(sid_data->reg_base + round_down(offset, 4));
|
|
sid_key >>= (offset % 4) * 8;
|
|
|
|
return sid_key; /* Only return the last byte */
|
|
}
|
|
|
|
static ssize_t sid_read(struct file *fd, struct kobject *kobj,
|
|
struct bin_attribute *attr, char *buf,
|
|
loff_t pos, size_t size)
|
|
{
|
|
struct platform_device *pdev;
|
|
struct sunxi_sid_data *sid_data;
|
|
int i;
|
|
|
|
pdev = to_platform_device(kobj_to_dev(kobj));
|
|
sid_data = platform_get_drvdata(pdev);
|
|
|
|
if (pos < 0 || pos >= sid_data->keysize)
|
|
return 0;
|
|
if (size > sid_data->keysize - pos)
|
|
size = sid_data->keysize - pos;
|
|
|
|
for (i = 0; i < size; i++)
|
|
buf[i] = sunxi_sid_read_byte(sid_data, pos + i);
|
|
|
|
return i;
|
|
}
|
|
|
|
static struct bin_attribute sid_bin_attr = {
|
|
.attr = { .name = "eeprom", .mode = S_IRUGO, },
|
|
.read = sid_read,
|
|
};
|
|
|
|
static int sunxi_sid_remove(struct platform_device *pdev)
|
|
{
|
|
device_remove_bin_file(&pdev->dev, &sid_bin_attr);
|
|
dev_dbg(&pdev->dev, "driver unloaded\n");
|
|
|
|
return 0;
|
|
}
|
|
|
|
static const struct of_device_id sunxi_sid_of_match[] = {
|
|
{ .compatible = "allwinner,sun4i-a10-sid", .data = (void *)16},
|
|
{ .compatible = "allwinner,sun7i-a20-sid", .data = (void *)512},
|
|
{/* sentinel */},
|
|
};
|
|
MODULE_DEVICE_TABLE(of, sunxi_sid_of_match);
|
|
|
|
static int sunxi_sid_probe(struct platform_device *pdev)
|
|
{
|
|
struct sunxi_sid_data *sid_data;
|
|
struct resource *res;
|
|
const struct of_device_id *of_dev_id;
|
|
u8 *entropy;
|
|
unsigned int i;
|
|
|
|
sid_data = devm_kzalloc(&pdev->dev, sizeof(struct sunxi_sid_data),
|
|
GFP_KERNEL);
|
|
if (!sid_data)
|
|
return -ENOMEM;
|
|
|
|
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
|
|
sid_data->reg_base = devm_ioremap_resource(&pdev->dev, res);
|
|
if (IS_ERR(sid_data->reg_base))
|
|
return PTR_ERR(sid_data->reg_base);
|
|
|
|
of_dev_id = of_match_device(sunxi_sid_of_match, &pdev->dev);
|
|
if (!of_dev_id)
|
|
return -ENODEV;
|
|
sid_data->keysize = (int)of_dev_id->data;
|
|
|
|
platform_set_drvdata(pdev, sid_data);
|
|
|
|
sid_bin_attr.size = sid_data->keysize;
|
|
if (device_create_bin_file(&pdev->dev, &sid_bin_attr))
|
|
return -ENODEV;
|
|
|
|
entropy = kzalloc(sizeof(u8) * sid_data->keysize, GFP_KERNEL);
|
|
for (i = 0; i < sid_data->keysize; i++)
|
|
entropy[i] = sunxi_sid_read_byte(sid_data, i);
|
|
add_device_randomness(entropy, sid_data->keysize);
|
|
kfree(entropy);
|
|
|
|
dev_dbg(&pdev->dev, "loaded\n");
|
|
|
|
return 0;
|
|
}
|
|
|
|
static struct platform_driver sunxi_sid_driver = {
|
|
.probe = sunxi_sid_probe,
|
|
.remove = sunxi_sid_remove,
|
|
.driver = {
|
|
.name = DRV_NAME,
|
|
.of_match_table = sunxi_sid_of_match,
|
|
},
|
|
};
|
|
module_platform_driver(sunxi_sid_driver);
|
|
|
|
MODULE_AUTHOR("Oliver Schinagl <oliver@schinagl.nl>");
|
|
MODULE_DESCRIPTION("Allwinner sunxi security id driver");
|
|
MODULE_LICENSE("GPL");
|