// SPDX-License-Identifier: GPL-2.0-or-later
/*
* JZ4780 EFUSE Memory Support driver
*
* Copyright (c) 2017 PrasannaKumar Muralidharan <prasannatsmkumar@gmail.com>
* Copyright (c) 2020 H. Nikolaus Schaller <hns@goldelico.com>
*/
/*
* Currently supports JZ4780 efuse which has 8K programmable bit.
* Efuse is separated into seven segments as below:
*
* -----------------------------------------------------------------------
* | 64 bit | 128 bit | 128 bit | 3520 bit | 8 bit | 2296 bit | 2048 bit |
* -----------------------------------------------------------------------
*
* The rom itself is accessed using a 9 bit address line and an 8 word wide bus
* which reads/writes based on strobes. The strobe is configured in the config
* register and is based on number of cycles of the bus clock.
*
* Driver supports read only as the writes are done in the Factory.
*/
#include <linux/bitops.h>
#include <linux/clk.h>
#include <linux/module.h>
#include <linux/nvmem-provider.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>
#include <linux/timer.h>
#define JZ_EFUCTRL (0x0) /* Control Register */
#define JZ_EFUCFG (0x4) /* Configure Register*/
#define JZ_EFUSTATE (0x8) /* Status Register */
#define JZ_EFUDATA(n) (0xC + (n) * 4)
/* We read 32 byte chunks to avoid complexity in the driver. */
#define JZ_EFU_READ_SIZE 32
#define EFUCTRL_ADDR_MASK 0x3FF
#define EFUCTRL_ADDR_SHIFT 21
#define EFUCTRL_LEN_MASK 0x1F
#define EFUCTRL_LEN_SHIFT 16
#define EFUCTRL_PG_EN BIT(15)
#define EFUCTRL_WR_EN BIT(1)
#define EFUCTRL_RD_EN BIT(0)
#define EFUCFG_INT_EN BIT(31)
#define EFUCFG_RD_ADJ_MASK 0xF
#define EFUCFG_RD_ADJ_SHIFT 20
#define EFUCFG_RD_STR_MASK 0xF
#define EFUCFG_RD_STR_SHIFT 16
#define EFUCFG_WR_ADJ_MASK 0xF
#define EFUCFG_WR_ADJ_SHIFT 12
#define EFUCFG_WR_STR_MASK 0xFFF
#define EFUCFG_WR_STR_SHIFT 0
#define EFUSTATE_WR_DONE BIT(1)
#define EFUSTATE_RD_DONE BIT(0)
struct jz4780_efuse {
struct device *dev;
struct regmap *map;
struct clk *clk;
};
/* main entry point */
static int jz4780_efuse_read(void *context, unsigned int offset,
void *val, size_t bytes)
{
struct jz4780_efuse *efuse = context;
while (bytes > 0) {
size_t start = offset & ~(JZ_EFU_READ_SIZE - 1);
size_t chunk = min(bytes, (start + JZ_EFU_READ_SIZE)
- offset);
char buf[JZ_EFU_READ_SIZE];
unsigned int tmp;
u32 ctrl;
int ret;
ctrl = (start << EFUCTRL_ADDR_SHIFT)
| ((JZ_EFU_READ_SIZE - 1) << EFUCTRL_LEN_SHIFT)
| EFUCTRL_RD_EN;
regmap_update_bits(efuse->map, JZ_EFUCTRL,
(EFUCTRL_ADDR_MASK << EFUCTRL_ADDR_SHIFT) |
(EFUCTRL_LEN_MASK << EFUCTRL_LEN_SHIFT) |
EFUCTRL_PG_EN | EFUCTRL_WR_EN |
EFUCTRL_RD_EN,
ctrl);
ret = regmap_read_poll_timeout(efuse->map, JZ_EFUSTATE,
tmp, tmp & EFUSTATE_RD_DONE,
1 * MSEC_PER_SEC,
50 * MSEC_PER_SEC);
if (ret < 0) {
dev_err(efuse->dev, "Time out while reading efuse data");
return ret;
}
ret = regmap_bulk_read(efuse->map, JZ_EFUDATA(0),
buf, JZ_EFU_READ_SIZE / sizeof(u32));
if (ret < 0)
return ret;
memcpy(val, &buf[offset - start], chunk);
val += chunk;
offset += chunk;
bytes -= chunk;
}
return 0;
}
static struct nvmem_config jz4780_efuse_nvmem_config = {
.name = "jz4780-efuse",
.size = 1024,
.word_size = 1,
.stride = 1,
.owner = THIS_MODULE,
.reg_read = jz4780_efuse_read,
};
static const struct regmap_config jz4780_efuse_regmap_config = {
.reg_bits = 32,
.val_bits = 32,
.reg_stride = 4,
.max_register = JZ_EFUDATA(7),
};
static void clk_disable_unprepare_helper(void *clock)
{
clk_disable_unprepare(clock);
}
static int jz4780_efuse_probe(struct platform_device *pdev)
{
struct nvmem_device *nvmem;
struct jz4780_efuse *efuse;
struct nvmem_config cfg;
unsigned long clk_rate;
unsigned long rd_adj;
unsigned long rd_strobe;
struct device *dev = &pdev->dev;
void __iomem *regs;
int ret;
efuse = devm_kzalloc(dev, sizeof(*efuse), GFP_KERNEL);
if (!efuse)
return -ENOMEM;
regs = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(regs))
return PTR_ERR(regs);
efuse->map = devm_regmap_init_mmio(dev, regs,
&jz4780_efuse_regmap_config);
if (IS_ERR(efuse->map))
return PTR_ERR(efuse->map);
efuse->clk = devm_clk_get(&pdev->dev, NULL);
if (IS_ERR(efuse->clk))
return PTR_ERR(efuse->clk);
ret = clk_prepare_enable(efuse->clk);
if (ret < 0)
return ret;
ret = devm_add_action_or_reset(&pdev->dev,
clk_disable_unprepare_helper,
efuse->clk);
if (ret < 0)
return ret;
clk_rate = clk_get_rate(efuse->clk);
efuse->dev = dev;
/*
* rd_adj and rd_strobe are 4 bit values
* conditions:
* bus clk_period * (rd_adj + 1) > 6.5ns
* bus clk_period * (rd_adj + 5 + rd_strobe) > 35ns
* i.e. rd_adj >= 6.5ns / clk_period
* i.e. rd_strobe >= 35 ns / clk_period - 5 - rd_adj + 1
* constants:
* 1 / 6.5ns == 153846154 Hz
* 1 / 35ns == 28571429 Hz
*/
rd_adj = clk_rate / 153846154;
rd_strobe = clk_rate / 28571429 - 5 - rd_adj + 1;
if (rd_adj > EFUCFG_RD_ADJ_MASK ||
rd_strobe > EFUCFG_RD_STR_MASK) {
dev_err(&pdev->dev, "Cannot set clock configuration\n");
return -EINVAL;
}
regmap_update_bits(efuse->map, JZ_EFUCFG,
(EFUCFG_RD_ADJ_MASK << EFUCFG_RD_ADJ_SHIFT) |
(EFUCFG_RD_STR_MASK << EFUCFG_RD_STR_SHIFT),
(rd_adj << EFUCFG_RD_ADJ_SHIFT) |
(rd_strobe << EFUCFG_RD_STR_SHIFT));
cfg = jz4780_efuse_nvmem_config;
cfg.dev = &pdev->dev;
cfg.priv = efuse;
nvmem = devm_nvmem_register(dev, &cfg);
if (IS_ERR(nvmem))
return PTR_ERR(nvmem);
return 0;
}
static const struct of_device_id jz4780_efuse_match[] = {
{ .compatible = "ingenic,jz4780-efuse" },
{ /* sentinel */ },
};
MODULE_DEVICE_TABLE(of, jz4780_efuse_match);
static struct platform_driver jz4780_efuse_driver = {
.probe = jz4780_efuse_probe,
.driver = {
.name = "jz4780-efuse",
.of_match_table = jz4780_efuse_match,
},
};
module_platform_driver(jz4780_efuse_driver);
MODULE_AUTHOR("PrasannaKumar Muralidharan <prasannatsmkumar@gmail.com>");
MODULE_AUTHOR("H. Nikolaus Schaller <hns@goldelico.com>");
MODULE_AUTHOR("Paul Cercueil <paul@crapouillou.net>");
MODULE_DESCRIPTION("Ingenic JZ4780 efuse driver");
MODULE_LICENSE("GPL v2");
