/* * 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 = offset; i < offset + bytes; i += efuse->config.word_size) { addr = 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");