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108 lines
2.8 KiB
108 lines
2.8 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* NXP LPC18xx/43xx OTP memory NVMEM driver |
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* |
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* Copyright (c) 2016 Joachim Eastwood <[email protected]> |
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* |
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* Based on the imx ocotp driver, |
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* Copyright (c) 2015 Pengutronix, Philipp Zabel <[email protected]> |
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* |
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* TODO: add support for writing OTP register via API in boot ROM. |
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*/ |
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#include <linux/io.h> |
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#include <linux/module.h> |
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#include <linux/nvmem-provider.h> |
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#include <linux/of.h> |
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#include <linux/of_device.h> |
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#include <linux/platform_device.h> |
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#include <linux/slab.h> |
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/* |
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* LPC18xx OTP memory contains 4 banks with 4 32-bit words. Bank 0 starts |
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* at offset 0 from the base. |
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* |
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* Bank 0 contains the part ID for Flashless devices and is reseverd for |
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* devices with Flash. |
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* Bank 1/2 is generale purpose or AES key storage for secure devices. |
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* Bank 3 contains control data, USB ID and generale purpose words. |
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*/ |
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#define LPC18XX_OTP_NUM_BANKS 4 |
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#define LPC18XX_OTP_WORDS_PER_BANK 4 |
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#define LPC18XX_OTP_WORD_SIZE sizeof(u32) |
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#define LPC18XX_OTP_SIZE (LPC18XX_OTP_NUM_BANKS * \ |
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LPC18XX_OTP_WORDS_PER_BANK * \ |
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LPC18XX_OTP_WORD_SIZE) |
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struct lpc18xx_otp { |
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void __iomem *base; |
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}; |
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static int lpc18xx_otp_read(void *context, unsigned int offset, |
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void *val, size_t bytes) |
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{ |
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struct lpc18xx_otp *otp = context; |
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unsigned int count = bytes >> 2; |
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u32 index = offset >> 2; |
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u32 *buf = val; |
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int i; |
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if (count > (LPC18XX_OTP_SIZE - index)) |
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count = LPC18XX_OTP_SIZE - index; |
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for (i = index; i < (index + count); i++) |
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*buf++ = readl(otp->base + i * LPC18XX_OTP_WORD_SIZE); |
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return 0; |
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} |
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static struct nvmem_config lpc18xx_otp_nvmem_config = { |
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.name = "lpc18xx-otp", |
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.read_only = true, |
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.word_size = LPC18XX_OTP_WORD_SIZE, |
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.stride = LPC18XX_OTP_WORD_SIZE, |
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.reg_read = lpc18xx_otp_read, |
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}; |
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static int lpc18xx_otp_probe(struct platform_device *pdev) |
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{ |
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struct nvmem_device *nvmem; |
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struct lpc18xx_otp *otp; |
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struct resource *res; |
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otp = devm_kzalloc(&pdev->dev, sizeof(*otp), GFP_KERNEL); |
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if (!otp) |
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return -ENOMEM; |
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res = platform_get_resource(pdev, IORESOURCE_MEM, 0); |
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otp->base = devm_ioremap_resource(&pdev->dev, res); |
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if (IS_ERR(otp->base)) |
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return PTR_ERR(otp->base); |
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lpc18xx_otp_nvmem_config.size = LPC18XX_OTP_SIZE; |
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lpc18xx_otp_nvmem_config.dev = &pdev->dev; |
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lpc18xx_otp_nvmem_config.priv = otp; |
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nvmem = devm_nvmem_register(&pdev->dev, &lpc18xx_otp_nvmem_config); |
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return PTR_ERR_OR_ZERO(nvmem); |
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} |
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static const struct of_device_id lpc18xx_otp_dt_ids[] = { |
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{ .compatible = "nxp,lpc1850-otp" }, |
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{ }, |
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}; |
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MODULE_DEVICE_TABLE(of, lpc18xx_otp_dt_ids); |
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static struct platform_driver lpc18xx_otp_driver = { |
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.probe = lpc18xx_otp_probe, |
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.driver = { |
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.name = "lpc18xx_otp", |
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.of_match_table = lpc18xx_otp_dt_ids, |
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}, |
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}; |
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module_platform_driver(lpc18xx_otp_driver); |
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MODULE_AUTHOR("Joachim Eastwoood <[email protected]>"); |
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MODULE_DESCRIPTION("NXP LPC18xx OTP NVMEM driver"); |
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MODULE_LICENSE("GPL v2");
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