/* * i.MX6 OCOTP fusebox driver * * Copyright (c) 2015 Pengutronix, Philipp Zabel * * Based on the barebox ocotp driver, * Copyright (c) 2010 Baruch Siach , * Orex Computed Radiography * * Write support based on the fsl_otp driver, * Copyright (C) 2010-2013 Freescale Semiconductor, Inc * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 * as published by the Free Software Foundation. * * http://www.opensource.org/licenses/gpl-license.html * http://www.gnu.org/copyleft/gpl.html */ #include #include #include #include #include #include #include #include #include #include #define IMX_OCOTP_OFFSET_B0W0 0x400 /* Offset from base address of the * OTP Bank0 Word0 */ #define IMX_OCOTP_OFFSET_PER_WORD 0x10 /* Offset between the start addr * of two consecutive OTP words. */ #define IMX_OCOTP_ADDR_CTRL 0x0000 #define IMX_OCOTP_ADDR_CTRL_SET 0x0004 #define IMX_OCOTP_ADDR_CTRL_CLR 0x0008 #define IMX_OCOTP_ADDR_TIMING 0x0010 #define IMX_OCOTP_ADDR_DATA 0x0020 #define IMX_OCOTP_BM_CTRL_ADDR 0x0000007F #define IMX_OCOTP_BM_CTRL_BUSY 0x00000100 #define IMX_OCOTP_BM_CTRL_ERROR 0x00000200 #define IMX_OCOTP_BM_CTRL_REL_SHADOWS 0x00000400 #define DEF_RELAX 20 /* > 16.5ns */ #define IMX_OCOTP_WR_UNLOCK 0x3E770000 #define IMX_OCOTP_READ_LOCKED_VAL 0xBADABADA static DEFINE_MUTEX(ocotp_mutex); struct ocotp_priv { struct device *dev; struct clk *clk; void __iomem *base; unsigned int nregs; struct nvmem_config *config; }; static int imx_ocotp_wait_for_busy(void __iomem *base, u32 flags) { int count; u32 c, mask; mask = IMX_OCOTP_BM_CTRL_BUSY | IMX_OCOTP_BM_CTRL_ERROR | flags; for (count = 10000; count >= 0; count--) { c = readl(base + IMX_OCOTP_ADDR_CTRL); if (!(c & mask)) break; cpu_relax(); } if (count < 0) { /* HW_OCOTP_CTRL[ERROR] will be set under the following * conditions: * - A write is performed to a shadow register during a shadow * reload (essentially, while HW_OCOTP_CTRL[RELOAD_SHADOWS] is * set. In addition, the contents of the shadow register shall * not be updated. * - A write is performed to a shadow register which has been * locked. * - A read is performed to from a shadow register which has * been read locked. * - A program is performed to a fuse word which has been locked * - A read is performed to from a fuse word which has been read * locked. */ if (c & IMX_OCOTP_BM_CTRL_ERROR) return -EPERM; return -ETIMEDOUT; } return 0; } static void imx_ocotp_clr_err_if_set(void __iomem *base) { u32 c; c = readl(base + IMX_OCOTP_ADDR_CTRL); if (!(c & IMX_OCOTP_BM_CTRL_ERROR)) return; writel(IMX_OCOTP_BM_CTRL_ERROR, base + IMX_OCOTP_ADDR_CTRL_CLR); } static int imx_ocotp_read(void *context, unsigned int offset, void *val, size_t bytes) { struct ocotp_priv *priv = context; unsigned int count; u32 *buf = val; int i, ret; u32 index; index = offset >> 2; count = bytes >> 2; if (count > (priv->nregs - index)) count = priv->nregs - index; mutex_lock(&ocotp_mutex); ret = clk_prepare_enable(priv->clk); if (ret < 0) { mutex_unlock(&ocotp_mutex); dev_err(priv->dev, "failed to prepare/enable ocotp clk\n"); return ret; } ret = imx_ocotp_wait_for_busy(priv->base, 0); if (ret < 0) { dev_err(priv->dev, "timeout during read setup\n"); goto read_end; } for (i = index; i < (index + count); i++) { *buf++ = readl(priv->base + IMX_OCOTP_OFFSET_B0W0 + i * IMX_OCOTP_OFFSET_PER_WORD); /* 47.3.1.2 * For "read locked" registers 0xBADABADA will be returned and * HW_OCOTP_CTRL[ERROR] will be set. It must be cleared by * software before any new write, read or reload access can be * issued */ if (*(buf - 1) == IMX_OCOTP_READ_LOCKED_VAL) imx_ocotp_clr_err_if_set(priv->base); } ret = 0; read_end: clk_disable_unprepare(priv->clk); mutex_unlock(&ocotp_mutex); return ret; } static int imx_ocotp_write(void *context, unsigned int offset, void *val, size_t bytes) { struct ocotp_priv *priv = context; u32 *buf = val; int ret; unsigned long clk_rate = 0; unsigned long strobe_read, relax, strobe_prog; u32 timing = 0; u32 ctrl; u8 waddr; /* allow only writing one complete OTP word at a time */ if ((bytes != priv->config->word_size) || (offset % priv->config->word_size)) return -EINVAL; mutex_lock(&ocotp_mutex); ret = clk_prepare_enable(priv->clk); if (ret < 0) { mutex_unlock(&ocotp_mutex); dev_err(priv->dev, "failed to prepare/enable ocotp clk\n"); return ret; } /* 47.3.1.3.1 * Program HW_OCOTP_TIMING[STROBE_PROG] and HW_OCOTP_TIMING[RELAX] * fields with timing values to match the current frequency of the * ipg_clk. OTP writes will work at maximum bus frequencies as long * as the HW_OCOTP_TIMING parameters are set correctly. */ clk_rate = clk_get_rate(priv->clk); relax = clk_rate / (1000000000 / DEF_RELAX) - 1; strobe_prog = clk_rate / (1000000000 / 10000) + 2 * (DEF_RELAX + 1) - 1; strobe_read = clk_rate / (1000000000 / 40) + 2 * (DEF_RELAX + 1) - 1; timing = strobe_prog & 0x00000FFF; timing |= (relax << 12) & 0x0000F000; timing |= (strobe_read << 16) & 0x003F0000; writel(timing, priv->base + IMX_OCOTP_ADDR_TIMING); /* 47.3.1.3.2 * Check that HW_OCOTP_CTRL[BUSY] and HW_OCOTP_CTRL[ERROR] are clear. * Overlapped accesses are not supported by the controller. Any pending * write or reload must be completed before a write access can be * requested. */ ret = imx_ocotp_wait_for_busy(priv->base, 0); if (ret < 0) { dev_err(priv->dev, "timeout during timing setup\n"); goto write_end; } /* 47.3.1.3.3 * Write the requested address to HW_OCOTP_CTRL[ADDR] and program the * unlock code into HW_OCOTP_CTRL[WR_UNLOCK]. This must be programmed * for each write access. The lock code is documented in the register * description. Both the unlock code and address can be written in the * same operation. */ /* OTP write/read address specifies one of 128 word address locations */ waddr = offset / 4; ctrl = readl(priv->base + IMX_OCOTP_ADDR_CTRL); ctrl &= ~IMX_OCOTP_BM_CTRL_ADDR; ctrl |= waddr & IMX_OCOTP_BM_CTRL_ADDR; ctrl |= IMX_OCOTP_WR_UNLOCK; writel(ctrl, priv->base + IMX_OCOTP_ADDR_CTRL); /* 47.3.1.3.4 * Write the data to the HW_OCOTP_DATA register. This will automatically * set HW_OCOTP_CTRL[BUSY] and clear HW_OCOTP_CTRL[WR_UNLOCK]. To * protect programming same OTP bit twice, before program OCOTP will * automatically read fuse value in OTP and use read value to mask * program data. The controller will use masked program data to program * a 32-bit word in the OTP per the address in HW_OCOTP_CTRL[ADDR]. Bit * fields with 1's will result in that OTP bit being programmed. Bit * fields with 0's will be ignored. At the same time that the write is * accepted, the controller makes an internal copy of * HW_OCOTP_CTRL[ADDR] which cannot be updated until the next write * sequence is initiated. This copy guarantees that erroneous writes to * HW_OCOTP_CTRL[ADDR] will not affect an active write operation. It * should also be noted that during the programming HW_OCOTP_DATA will * shift right (with zero fill). This shifting is required to program * the OTP serially. During the write operation, HW_OCOTP_DATA cannot be * modified. */ writel(*buf, priv->base + IMX_OCOTP_ADDR_DATA); /* 47.4.1.4.5 * Once complete, the controller will clear BUSY. A write request to a * protected or locked region will result in no OTP access and no * setting of HW_OCOTP_CTRL[BUSY]. In addition HW_OCOTP_CTRL[ERROR] will * be set. It must be cleared by software before any new write access * can be issued. */ ret = imx_ocotp_wait_for_busy(priv->base, 0); if (ret < 0) { if (ret == -EPERM) { dev_err(priv->dev, "failed write to locked region"); imx_ocotp_clr_err_if_set(priv->base); } else { dev_err(priv->dev, "timeout during data write\n"); } goto write_end; } /* 47.3.1.4 * Write Postamble: Due to internal electrical characteristics of the * OTP during writes, all OTP operations following a write must be * separated by 2 us after the clearing of HW_OCOTP_CTRL_BUSY following * the write. */ udelay(2); /* reload all shadow registers */ writel(IMX_OCOTP_BM_CTRL_REL_SHADOWS, priv->base + IMX_OCOTP_ADDR_CTRL_SET); ret = imx_ocotp_wait_for_busy(priv->base, IMX_OCOTP_BM_CTRL_REL_SHADOWS); if (ret < 0) { dev_err(priv->dev, "timeout during shadow register reload\n"); goto write_end; } write_end: clk_disable_unprepare(priv->clk); mutex_unlock(&ocotp_mutex); if (ret < 0) return ret; return bytes; } static struct nvmem_config imx_ocotp_nvmem_config = { .name = "imx-ocotp", .read_only = false, .word_size = 4, .stride = 4, .reg_read = imx_ocotp_read, .reg_write = imx_ocotp_write, }; static const struct of_device_id imx_ocotp_dt_ids[] = { { .compatible = "fsl,imx6q-ocotp", (void *)128 }, { .compatible = "fsl,imx6sl-ocotp", (void *)64 }, { .compatible = "fsl,imx6sx-ocotp", (void *)128 }, { .compatible = "fsl,imx6ul-ocotp", (void *)128 }, { .compatible = "fsl,imx7d-ocotp", (void *)64 }, { }, }; MODULE_DEVICE_TABLE(of, imx_ocotp_dt_ids); static int imx_ocotp_probe(struct platform_device *pdev) { const struct of_device_id *of_id; struct device *dev = &pdev->dev; struct resource *res; struct ocotp_priv *priv; struct nvmem_device *nvmem; priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL); if (!priv) return -ENOMEM; priv->dev = dev; res = platform_get_resource(pdev, IORESOURCE_MEM, 0); priv->base = devm_ioremap_resource(dev, res); if (IS_ERR(priv->base)) return PTR_ERR(priv->base); priv->clk = devm_clk_get(dev, NULL); if (IS_ERR(priv->clk)) return PTR_ERR(priv->clk); of_id = of_match_device(imx_ocotp_dt_ids, dev); priv->nregs = (unsigned long)of_id->data; imx_ocotp_nvmem_config.size = 4 * priv->nregs; imx_ocotp_nvmem_config.dev = dev; imx_ocotp_nvmem_config.priv = priv; priv->config = &imx_ocotp_nvmem_config; nvmem = nvmem_register(&imx_ocotp_nvmem_config); if (IS_ERR(nvmem)) return PTR_ERR(nvmem); platform_set_drvdata(pdev, nvmem); return 0; } static int imx_ocotp_remove(struct platform_device *pdev) { struct nvmem_device *nvmem = platform_get_drvdata(pdev); return nvmem_unregister(nvmem); } static struct platform_driver imx_ocotp_driver = { .probe = imx_ocotp_probe, .remove = imx_ocotp_remove, .driver = { .name = "imx_ocotp", .of_match_table = imx_ocotp_dt_ids, }, }; module_platform_driver(imx_ocotp_driver); MODULE_AUTHOR("Philipp Zabel "); MODULE_DESCRIPTION("i.MX6 OCOTP fuse box driver"); MODULE_LICENSE("GPL v2");