forked from Minki/linux
9c7b16eb35
This patch moves to nvmem support in the driver to use callback instead of regmap. Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
142 lines
3.6 KiB
C
142 lines
3.6 KiB
C
/*
|
|
* Allwinner sunXi SoCs Security ID support.
|
|
*
|
|
* Copyright (c) 2013 Oliver Schinagl <oliver@schinagl.nl>
|
|
* Copyright (C) 2014 Maxime Ripard <maxime.ripard@free-electrons.com>
|
|
*
|
|
* 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.
|
|
*/
|
|
|
|
#include <linux/device.h>
|
|
#include <linux/io.h>
|
|
#include <linux/module.h>
|
|
#include <linux/nvmem-provider.h>
|
|
#include <linux/of.h>
|
|
#include <linux/platform_device.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/random.h>
|
|
|
|
static struct nvmem_config econfig = {
|
|
.name = "sunxi-sid",
|
|
.read_only = true,
|
|
.stride = 4,
|
|
.word_size = 1,
|
|
.owner = THIS_MODULE,
|
|
};
|
|
|
|
struct sunxi_sid {
|
|
void __iomem *base;
|
|
};
|
|
|
|
/* 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 *sid,
|
|
const unsigned int offset)
|
|
{
|
|
u32 sid_key;
|
|
|
|
sid_key = ioread32be(sid->base + round_down(offset, 4));
|
|
sid_key >>= (offset % 4) * 8;
|
|
|
|
return sid_key; /* Only return the last byte */
|
|
}
|
|
|
|
static int sunxi_sid_read(void *context, unsigned int offset,
|
|
void *val, size_t bytes)
|
|
{
|
|
struct sunxi_sid *sid = context;
|
|
u8 *buf = val;
|
|
|
|
while (bytes--)
|
|
*buf++ = sunxi_sid_read_byte(sid, offset++);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int sunxi_sid_probe(struct platform_device *pdev)
|
|
{
|
|
struct device *dev = &pdev->dev;
|
|
struct resource *res;
|
|
struct nvmem_device *nvmem;
|
|
struct sunxi_sid *sid;
|
|
int ret, i, size;
|
|
char *randomness;
|
|
|
|
sid = devm_kzalloc(dev, sizeof(*sid), GFP_KERNEL);
|
|
if (!sid)
|
|
return -ENOMEM;
|
|
|
|
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
|
|
sid->base = devm_ioremap_resource(dev, res);
|
|
if (IS_ERR(sid->base))
|
|
return PTR_ERR(sid->base);
|
|
|
|
size = resource_size(res) - 1;
|
|
econfig.size = resource_size(res);
|
|
econfig.dev = dev;
|
|
econfig.reg_read = sunxi_sid_read;
|
|
econfig.priv = sid;
|
|
nvmem = nvmem_register(&econfig);
|
|
if (IS_ERR(nvmem))
|
|
return PTR_ERR(nvmem);
|
|
|
|
randomness = kzalloc(sizeof(u8) * (size), GFP_KERNEL);
|
|
if (!randomness) {
|
|
ret = -EINVAL;
|
|
goto err_unreg_nvmem;
|
|
}
|
|
|
|
for (i = 0; i < size; i++)
|
|
randomness[i] = sunxi_sid_read_byte(sid, i);
|
|
|
|
add_device_randomness(randomness, size);
|
|
kfree(randomness);
|
|
|
|
platform_set_drvdata(pdev, nvmem);
|
|
|
|
return 0;
|
|
|
|
err_unreg_nvmem:
|
|
nvmem_unregister(nvmem);
|
|
return ret;
|
|
}
|
|
|
|
static int sunxi_sid_remove(struct platform_device *pdev)
|
|
{
|
|
struct nvmem_device *nvmem = platform_get_drvdata(pdev);
|
|
|
|
return nvmem_unregister(nvmem);
|
|
}
|
|
|
|
static const struct of_device_id sunxi_sid_of_match[] = {
|
|
{ .compatible = "allwinner,sun4i-a10-sid" },
|
|
{ .compatible = "allwinner,sun7i-a20-sid" },
|
|
{/* sentinel */},
|
|
};
|
|
MODULE_DEVICE_TABLE(of, sunxi_sid_of_match);
|
|
|
|
static struct platform_driver sunxi_sid_driver = {
|
|
.probe = sunxi_sid_probe,
|
|
.remove = sunxi_sid_remove,
|
|
.driver = {
|
|
.name = "eeprom-sunxi-sid",
|
|
.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");
|