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/*
* Amlogic Meson6, Meson8 and Meson8b eFuse Driver
*
* Copyright (c) 2017 Martin Blumenstingl <martin.blumenstingl@googlemail.com>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of version 2 of the GNU General Public License 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/bitfield.h>
#include <linux/bitops.h>
#include <linux/clk.h>
#include <linux/delay.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/sizes.h>
#include <linux/slab.h>
#define MESON_MX_EFUSE_CNTL1 0x04
#define MESON_MX_EFUSE_CNTL1_PD_ENABLE BIT(27)
#define MESON_MX_EFUSE_CNTL1_AUTO_RD_BUSY BIT(26)
#define MESON_MX_EFUSE_CNTL1_AUTO_RD_START BIT(25)
#define MESON_MX_EFUSE_CNTL1_AUTO_RD_ENABLE BIT(24)
#define MESON_MX_EFUSE_CNTL1_BYTE_WR_DATA GENMASK(23, 16)
#define MESON_MX_EFUSE_CNTL1_AUTO_WR_BUSY BIT(14)
#define MESON_MX_EFUSE_CNTL1_AUTO_WR_START BIT(13)
#define MESON_MX_EFUSE_CNTL1_AUTO_WR_ENABLE BIT(12)
#define MESON_MX_EFUSE_CNTL1_BYTE_ADDR_SET BIT(11)
#define MESON_MX_EFUSE_CNTL1_BYTE_ADDR_MASK GENMASK(10, 0)
#define MESON_MX_EFUSE_CNTL2 0x08
#define MESON_MX_EFUSE_CNTL4 0x10
#define MESON_MX_EFUSE_CNTL4_ENCRYPT_ENABLE BIT(10)
struct meson_mx_efuse_platform_data {
const char *name;
unsigned int word_size;
};
struct meson_mx_efuse {
void __iomem *base;
struct clk *core_clk;
struct nvmem_device *nvmem;
struct nvmem_config config;
};
static void meson_mx_efuse_mask_bits(struct meson_mx_efuse *efuse, u32 reg,
u32 mask, u32 set)
{
u32 data;
data = readl(efuse->base + reg);
data &= ~mask;
data |= (set & mask);
writel(data, efuse->base + reg);
}
static int meson_mx_efuse_hw_enable(struct meson_mx_efuse *efuse)
{
int err;
err = clk_prepare_enable(efuse->core_clk);
if (err)
return err;
/* power up the efuse */
meson_mx_efuse_mask_bits(efuse, MESON_MX_EFUSE_CNTL1,
MESON_MX_EFUSE_CNTL1_PD_ENABLE, 0);
meson_mx_efuse_mask_bits(efuse, MESON_MX_EFUSE_CNTL4,
MESON_MX_EFUSE_CNTL4_ENCRYPT_ENABLE, 0);
return 0;
}
static void meson_mx_efuse_hw_disable(struct meson_mx_efuse *efuse)
{
meson_mx_efuse_mask_bits(efuse, MESON_MX_EFUSE_CNTL1,
MESON_MX_EFUSE_CNTL1_PD_ENABLE,
MESON_MX_EFUSE_CNTL1_PD_ENABLE);
clk_disable_unprepare(efuse->core_clk);
}
static int meson_mx_efuse_read_addr(struct meson_mx_efuse *efuse,
unsigned int addr, u32 *value)
{
int err;
u32 regval;
/* write the address to read */
regval = FIELD_PREP(MESON_MX_EFUSE_CNTL1_BYTE_ADDR_MASK, addr);
meson_mx_efuse_mask_bits(efuse, MESON_MX_EFUSE_CNTL1,
MESON_MX_EFUSE_CNTL1_BYTE_ADDR_MASK, regval);
/* inform the hardware that we changed the address */
meson_mx_efuse_mask_bits(efuse, MESON_MX_EFUSE_CNTL1,
MESON_MX_EFUSE_CNTL1_BYTE_ADDR_SET,
MESON_MX_EFUSE_CNTL1_BYTE_ADDR_SET);
meson_mx_efuse_mask_bits(efuse, MESON_MX_EFUSE_CNTL1,
MESON_MX_EFUSE_CNTL1_BYTE_ADDR_SET, 0);
/* start the read process */
meson_mx_efuse_mask_bits(efuse, MESON_MX_EFUSE_CNTL1,
MESON_MX_EFUSE_CNTL1_AUTO_RD_START,
MESON_MX_EFUSE_CNTL1_AUTO_RD_START);
meson_mx_efuse_mask_bits(efuse, MESON_MX_EFUSE_CNTL1,
MESON_MX_EFUSE_CNTL1_AUTO_RD_START, 0);
/*
* perform a dummy read to ensure that the HW has the RD_BUSY bit set
* when polling for the status below.
*/
readl(efuse->base + MESON_MX_EFUSE_CNTL1);
err = readl_poll_timeout_atomic(efuse->base + MESON_MX_EFUSE_CNTL1,
regval,
(!(regval & MESON_MX_EFUSE_CNTL1_AUTO_RD_BUSY)),
1, 1000);
if (err) {
dev_err(efuse->config.dev,
"Timeout while reading efuse address %u\n", addr);
return err;
}
*value = readl(efuse->base + MESON_MX_EFUSE_CNTL2);
return 0;
}
static int meson_mx_efuse_read(void *context, unsigned int offset,
void *buf, size_t bytes)
{
struct meson_mx_efuse *efuse = context;
u32 tmp;
int err, i, addr;
err = meson_mx_efuse_hw_enable(efuse);
if (err)
return err;
meson_mx_efuse_mask_bits(efuse, MESON_MX_EFUSE_CNTL1,
MESON_MX_EFUSE_CNTL1_AUTO_RD_ENABLE,
MESON_MX_EFUSE_CNTL1_AUTO_RD_ENABLE);
for (i = 0; i < bytes; i += efuse->config.word_size) {
addr = (offset + i) / efuse->config.word_size;
err = meson_mx_efuse_read_addr(efuse, addr, &tmp);
if (err)
break;
memcpy(buf + i, &tmp, efuse->config.word_size);
}
meson_mx_efuse_mask_bits(efuse, MESON_MX_EFUSE_CNTL1,
MESON_MX_EFUSE_CNTL1_AUTO_RD_ENABLE, 0);
meson_mx_efuse_hw_disable(efuse);
return err;
}
static const struct meson_mx_efuse_platform_data meson6_efuse_data = {
.name = "meson6-efuse",
.word_size = 1,
};
static const struct meson_mx_efuse_platform_data meson8_efuse_data = {
.name = "meson8-efuse",
.word_size = 4,
};
static const struct meson_mx_efuse_platform_data meson8b_efuse_data = {
.name = "meson8b-efuse",
.word_size = 4,
};
static const struct of_device_id meson_mx_efuse_match[] = {
{ .compatible = "amlogic,meson6-efuse", .data = &meson6_efuse_data },
{ .compatible = "amlogic,meson8-efuse", .data = &meson8_efuse_data },
{ .compatible = "amlogic,meson8b-efuse", .data = &meson8b_efuse_data },
{ /* sentinel */ },
};
MODULE_DEVICE_TABLE(of, meson_mx_efuse_match);
static int meson_mx_efuse_probe(struct platform_device *pdev)
{
const struct meson_mx_efuse_platform_data *drvdata;
struct meson_mx_efuse *efuse;
struct resource *res;
drvdata = of_device_get_match_data(&pdev->dev);
if (!drvdata)
return -EINVAL;
efuse = devm_kzalloc(&pdev->dev, sizeof(*efuse), GFP_KERNEL);
if (!efuse)
return -ENOMEM;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
efuse->base = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(efuse->base))
return PTR_ERR(efuse->base);
efuse->config.name = devm_kstrdup(&pdev->dev, drvdata->name,
GFP_KERNEL);
efuse->config.owner = THIS_MODULE;
efuse->config.dev = &pdev->dev;
efuse->config.priv = efuse;
efuse->config.stride = drvdata->word_size;
efuse->config.word_size = drvdata->word_size;
efuse->config.size = SZ_512;
efuse->config.read_only = true;
efuse->config.reg_read = meson_mx_efuse_read;
efuse->core_clk = devm_clk_get(&pdev->dev, "core");
if (IS_ERR(efuse->core_clk)) {
dev_err(&pdev->dev, "Failed to get core clock\n");
return PTR_ERR(efuse->core_clk);
}
efuse->nvmem = nvmem_register(&efuse->config);
if (IS_ERR(efuse->nvmem))
return PTR_ERR(efuse->nvmem);
platform_set_drvdata(pdev, efuse);
return 0;
}
static int meson_mx_efuse_remove(struct platform_device *pdev)
{
struct meson_mx_efuse *efuse = platform_get_drvdata(pdev);
return nvmem_unregister(efuse->nvmem);
}
static struct platform_driver meson_mx_efuse_driver = {
.probe = meson_mx_efuse_probe,
.remove = meson_mx_efuse_remove,
.driver = {
.name = "meson-mx-efuse",
.of_match_table = meson_mx_efuse_match,
},
};
module_platform_driver(meson_mx_efuse_driver);
MODULE_AUTHOR("Martin Blumenstingl <martin.blumenstingl@googlemail.com>");
MODULE_DESCRIPTION("Amlogic Meson MX eFuse NVMEM driver");
MODULE_LICENSE("GPL v2");
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