// SPDX-License-Identifier: GPL-2.0-only
/*
* Rockchip OTP Driver
*
* Copyright (c) 2018 Rockchip Electronics Co. Ltd.
* Author: Finley Xiao <finley.xiao@rock-chips.com>
*/
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/io.h>
#include <linux/iopoll.h>
#include <linux/module.h>
#include <linux/nvmem-provider.h>
#include <linux/reset.h>
#include <linux/slab.h>
#include <linux/of.h>
#include <linux/of_platform.h>
#include <linux/platform_device.h>
/* OTP Register Offsets */
#define OTPC_SBPI_CTRL 0x0020
#define OTPC_SBPI_CMD_VALID_PRE 0x0024
#define OTPC_SBPI_CS_VALID_PRE 0x0028
#define OTPC_SBPI_STATUS 0x002C
#define OTPC_USER_CTRL 0x0100
#define OTPC_USER_ADDR 0x0104
#define OTPC_USER_ENABLE 0x0108
#define OTPC_USER_Q 0x0124
#define OTPC_INT_STATUS 0x0304
#define OTPC_SBPI_CMD0_OFFSET 0x1000
#define OTPC_SBPI_CMD1_OFFSET 0x1004
/* OTP Register bits and masks */
#define OTPC_USER_ADDR_MASK GENMASK(31, 16)
#define OTPC_USE_USER BIT(0)
#define OTPC_USE_USER_MASK GENMASK(16, 16)
#define OTPC_USER_FSM_ENABLE BIT(0)
#define OTPC_USER_FSM_ENABLE_MASK GENMASK(16, 16)
#define OTPC_SBPI_DONE BIT(1)
#define OTPC_USER_DONE BIT(2)
#define SBPI_DAP_ADDR 0x02
#define SBPI_DAP_ADDR_SHIFT 8
#define SBPI_DAP_ADDR_MASK GENMASK(31, 24)
#define SBPI_CMD_VALID_MASK GENMASK(31, 16)
#define SBPI_DAP_CMD_WRF 0xC0
#define SBPI_DAP_REG_ECC 0x3A
#define SBPI_ECC_ENABLE 0x00
#define SBPI_ECC_DISABLE 0x09
#define SBPI_ENABLE BIT(0)
#define SBPI_ENABLE_MASK GENMASK(16, 16)
#define OTPC_TIMEOUT 10000
struct rockchip_otp {
struct device *dev;
void __iomem *base;
struct clk_bulk_data *clks;
int num_clks;
struct reset_control *rst;
};
/* list of required clocks */
static const char * const rockchip_otp_clocks[] = {
"otp", "apb_pclk", "phy",
};
struct rockchip_data {
int size;
};
static int rockchip_otp_reset(struct rockchip_otp *otp)
{
int ret;
ret = reset_control_assert(otp->rst);
if (ret) {
dev_err(otp->dev, "failed to assert otp phy %d\n", ret);
return ret;
}
udelay(2);
ret = reset_control_deassert(otp->rst);
if (ret) {
dev_err(otp->dev, "failed to deassert otp phy %d\n", ret);
return ret;
}
return 0;
}
static int rockchip_otp_wait_status(struct rockchip_otp *otp, u32 flag)
{
u32 status = 0;
int ret;
ret = readl_poll_timeout_atomic(otp->base + OTPC_INT_STATUS, status,
(status & flag), 1, OTPC_TIMEOUT);
if (ret)
return ret;
/* clean int status */
writel(flag, otp->base + OTPC_INT_STATUS);
return 0;
}
static int rockchip_otp_ecc_enable(struct rockchip_otp *otp, bool enable)
{
int ret = 0;
writel(SBPI_DAP_ADDR_MASK | (SBPI_DAP_ADDR << SBPI_DAP_ADDR_SHIFT),
otp->base + OTPC_SBPI_CTRL);
writel(SBPI_CMD_VALID_MASK | 0x1, otp->base + OTPC_SBPI_CMD_VALID_PRE);
writel(SBPI_DAP_CMD_WRF | SBPI_DAP_REG_ECC,
otp->base + OTPC_SBPI_CMD0_OFFSET);
if (enable)
writel(SBPI_ECC_ENABLE, otp->base + OTPC_SBPI_CMD1_OFFSET);
else
writel(SBPI_ECC_DISABLE, otp->base + OTPC_SBPI_CMD1_OFFSET);
writel(SBPI_ENABLE_MASK | SBPI_ENABLE, otp->base + OTPC_SBPI_CTRL);
ret = rockchip_otp_wait_status(otp, OTPC_SBPI_DONE);
if (ret < 0)
dev_err(otp->dev, "timeout during ecc_enable\n");
return ret;
}
static int rockchip_otp_read(void *context, unsigned int offset,
void *val, size_t bytes)
{
struct rockchip_otp *otp = context;
u8 *buf = val;
int ret = 0;
ret = clk_bulk_prepare_enable(otp->num_clks, otp->clks);
if (ret < 0) {
dev_err(otp->dev, "failed to prepare/enable clks\n");
return ret;
}
ret = rockchip_otp_reset(otp);
if (ret) {
dev_err(otp->dev, "failed to reset otp phy\n");
goto disable_clks;
}
ret = rockchip_otp_ecc_enable(otp, false);
if (ret < 0) {
dev_err(otp->dev, "rockchip_otp_ecc_enable err\n");
goto disable_clks;
}
writel(OTPC_USE_USER | OTPC_USE_USER_MASK, otp->base + OTPC_USER_CTRL);
udelay(5);
while (bytes--) {
writel(offset++ | OTPC_USER_ADDR_MASK,
otp->base + OTPC_USER_ADDR);
writel(OTPC_USER_FSM_ENABLE | OTPC_USER_FSM_ENABLE_MASK,
otp->base + OTPC_USER_ENABLE);
ret = rockchip_otp_wait_status(otp, OTPC_USER_DONE);
if (ret < 0) {
dev_err(otp->dev, "timeout during read setup\n");
goto read_end;
}
*buf++ = readb(otp->base + OTPC_USER_Q);
}
read_end:
writel(0x0 | OTPC_USE_USER_MASK, otp->base + OTPC_USER_CTRL);
disable_clks:
clk_bulk_disable_unprepare(otp->num_clks, otp->clks);
return ret;
}
static struct nvmem_config otp_config = {
.name = "rockchip-otp",
.owner = THIS_MODULE,
.read_only = true,
.stride = 1,
.word_size = 1,
.reg_read = rockchip_otp_read,
};
static const struct rockchip_data px30_data = {
.size = 0x40,
};
static const struct of_device_id rockchip_otp_match[] = {
{
.compatible = "rockchip,px30-otp",
.data = (void *)&px30_data,
},
{
.compatible = "rockchip,rk3308-otp",
.data = (void *)&px30_data,
},
{ /* sentinel */ },
};
MODULE_DEVICE_TABLE(of, rockchip_otp_match);
static int rockchip_otp_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct rockchip_otp *otp;
const struct rockchip_data *data;
struct nvmem_device *nvmem;
int ret, i;
data = of_device_get_match_data(dev);
if (!data) {
dev_err(dev, "failed to get match data\n");
return -EINVAL;
}
otp = devm_kzalloc(&pdev->dev, sizeof(struct rockchip_otp),
GFP_KERNEL);
if (!otp)
return -ENOMEM;
otp->dev = dev;
otp->base = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(otp->base))
return PTR_ERR(otp->base);
otp->num_clks = ARRAY_SIZE(rockchip_otp_clocks);
otp->clks = devm_kcalloc(dev, otp->num_clks,
sizeof(*otp->clks), GFP_KERNEL);
if (!otp->clks)
return -ENOMEM;
for (i = 0; i < otp->num_clks; ++i)
otp->clks[i].id = rockchip_otp_clocks[i];
ret = devm_clk_bulk_get(dev, otp->num_clks, otp->clks);
if (ret)
return ret;
otp->rst = devm_reset_control_get(dev, "phy");
if (IS_ERR(otp->rst))
return PTR_ERR(otp->rst);
otp_config.size = data->size;
otp_config.priv = otp;
otp_config.dev = dev;
nvmem = devm_nvmem_register(dev, &otp_config);
return PTR_ERR_OR_ZERO(nvmem);
}
static struct platform_driver rockchip_otp_driver = {
.probe = rockchip_otp_probe,
.driver = {
.name = "rockchip-otp",
.of_match_table = rockchip_otp_match,
},
};
module_platform_driver(rockchip_otp_driver);
MODULE_DESCRIPTION("Rockchip OTP driver");
MODULE_LICENSE("GPL v2");