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// SPDX-License-Identifier: GPL-2.0+
/*
* Allwinner sunXi SoCs Security ID support.
*
* Copyright (c) 2013 Oliver Schinagl <oliver@schinagl.nl>
* Copyright (C) 2014 Maxime Ripard <maxime.ripard@free-electrons.com>
*/
#include <linux/device.h>
#include <linux/io.h>
#include <linux/iopoll.h>
#include <linux/module.h>
#include <linux/nvmem-provider.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/random.h>
/* Registers and special values for doing register-based SID readout on H3 */
#define SUN8I_SID_PRCTL 0x40
#define SUN8I_SID_RDKEY 0x60
#define SUN8I_SID_OFFSET_MASK 0x1FF
#define SUN8I_SID_OFFSET_SHIFT 16
#define SUN8I_SID_OP_LOCK (0xAC << 8)
#define SUN8I_SID_READ BIT(1)
struct sunxi_sid_cfg {
u32 value_offset;
u32 size;
bool need_register_readout;
};
struct sunxi_sid {
void __iomem *base;
u32 value_offset;
};
static int sunxi_sid_read(void *context, unsigned int offset,
void *val, size_t bytes)
{
struct sunxi_sid *sid = context;
memcpy_fromio(val, sid->base + sid->value_offset + offset, bytes);
return 0;
}
static int sun8i_sid_register_readout(const struct sunxi_sid *sid,
const unsigned int offset,
u32 *out)
{
u32 reg_val;
int ret;
/* Set word, lock access, and set read command */
reg_val = (offset & SUN8I_SID_OFFSET_MASK)
<< SUN8I_SID_OFFSET_SHIFT;
reg_val |= SUN8I_SID_OP_LOCK | SUN8I_SID_READ;
writel(reg_val, sid->base + SUN8I_SID_PRCTL);
ret = readl_poll_timeout(sid->base + SUN8I_SID_PRCTL, reg_val,
!(reg_val & SUN8I_SID_READ), 100, 250000);
if (ret)
return ret;
if (out)
*out = readl(sid->base + SUN8I_SID_RDKEY);
writel(0, sid->base + SUN8I_SID_PRCTL);
return 0;
}
/*
* On Allwinner H3, the value on the 0x200 offset of the SID controller seems
* to be not reliable at all.
* Read by the registers instead.
*/
static int sun8i_sid_read_by_reg(void *context, unsigned int offset,
void *val, size_t bytes)
{
struct sunxi_sid *sid = context;
u32 word;
int ret;
/* .stride = 4 so offset is guaranteed to be aligned */
while (bytes >= 4) {
ret = sun8i_sid_register_readout(sid, offset, val);
if (ret)
return ret;
val += 4;
offset += 4;
bytes -= 4;
}
if (!bytes)
return 0;
/* Handle any trailing bytes */
ret = sun8i_sid_register_readout(sid, offset, &word);
if (ret)
return ret;
memcpy(val, &word, bytes);
return 0;
}
static int sunxi_sid_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct resource *res;
struct nvmem_config *nvmem_cfg;
struct nvmem_device *nvmem;
struct sunxi_sid *sid;
int size;
char *randomness;
const struct sunxi_sid_cfg *cfg;
sid = devm_kzalloc(dev, sizeof(*sid), GFP_KERNEL);
if (!sid)
return -ENOMEM;
cfg = of_device_get_match_data(dev);
if (!cfg)
return -EINVAL;
sid->value_offset = cfg->value_offset;
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 = cfg->size;
nvmem_cfg = devm_kzalloc(dev, sizeof(*nvmem_cfg), GFP_KERNEL);
if (!nvmem_cfg)
return -ENOMEM;
nvmem_cfg->dev = dev;
nvmem_cfg->name = "sunxi-sid";
nvmem_cfg->read_only = true;
nvmem_cfg->size = cfg->size;
nvmem_cfg->word_size = 1;
nvmem_cfg->stride = 4;
nvmem_cfg->priv = sid;
if (cfg->need_register_readout)
nvmem_cfg->reg_read = sun8i_sid_read_by_reg;
else
nvmem_cfg->reg_read = sunxi_sid_read;
nvmem = devm_nvmem_register(dev, nvmem_cfg);
if (IS_ERR(nvmem))
return PTR_ERR(nvmem);
randomness = kzalloc(size, GFP_KERNEL);
if (!randomness)
return -ENOMEM;
nvmem_cfg->reg_read(sid, 0, randomness, size);
add_device_randomness(randomness, size);
kfree(randomness);
platform_set_drvdata(pdev, nvmem);
return 0;
}
static const struct sunxi_sid_cfg sun4i_a10_cfg = {
.size = 0x10,
};
static const struct sunxi_sid_cfg sun7i_a20_cfg = {
.size = 0x200,
};
static const struct sunxi_sid_cfg sun8i_h3_cfg = {
.value_offset = 0x200,
.size = 0x100,
.need_register_readout = true,
};
static const struct sunxi_sid_cfg sun50i_a64_cfg = {
.value_offset = 0x200,
.size = 0x100,
};
static const struct sunxi_sid_cfg sun50i_h6_cfg = {
.value_offset = 0x200,
.size = 0x200,
};
static const struct of_device_id sunxi_sid_of_match[] = {
{ .compatible = "allwinner,sun4i-a10-sid", .data = &sun4i_a10_cfg },
{ .compatible = "allwinner,sun7i-a20-sid", .data = &sun7i_a20_cfg },
{ .compatible = "allwinner,sun8i-a83t-sid", .data = &sun50i_a64_cfg },
{ .compatible = "allwinner,sun8i-h3-sid", .data = &sun8i_h3_cfg },
{ .compatible = "allwinner,sun50i-a64-sid", .data = &sun50i_a64_cfg },
{ .compatible = "allwinner,sun50i-h5-sid", .data = &sun50i_a64_cfg },
{ .compatible = "allwinner,sun50i-h6-sid", .data = &sun50i_h6_cfg },
{/* sentinel */},
};
MODULE_DEVICE_TABLE(of, sunxi_sid_of_match);
static struct platform_driver sunxi_sid_driver = {
.probe = sunxi_sid_probe,
.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");
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