// 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");