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Diffstat (limited to '')
| -rw-r--r-- | drivers/nvmem/jz4780-efuse.c | 237 |
1 files changed, 237 insertions, 0 deletions
diff --git a/drivers/nvmem/jz4780-efuse.c b/drivers/nvmem/jz4780-efuse.c new file mode 100644 index 000000000..0b01b840e --- /dev/null +++ b/drivers/nvmem/jz4780-efuse.c @@ -0,0 +1,237 @@ +// 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); + + return PTR_ERR_OR_ZERO(nvmem); +} + +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"); |