diff options
Diffstat (limited to 'drivers/nvmem/meson-mx-efuse.c')
| -rw-r--r-- | drivers/nvmem/meson-mx-efuse.c | 253 |
1 files changed, 253 insertions, 0 deletions
diff --git a/drivers/nvmem/meson-mx-efuse.c b/drivers/nvmem/meson-mx-efuse.c new file mode 100644 index 000000000..a085563e3 --- /dev/null +++ b/drivers/nvmem/meson-mx-efuse.c @@ -0,0 +1,253 @@ +/* + * 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 = 0; i < bytes; i += efuse->config.word_size) { + addr = (offset + 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 = devm_nvmem_register(&pdev->dev, &efuse->config); + + return PTR_ERR_OR_ZERO(efuse->nvmem); +} + +static struct platform_driver meson_mx_efuse_driver = { + .probe = meson_mx_efuse_probe, + .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"); |