125 lines
3.2 KiB
C
125 lines
3.2 KiB
C
/*
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* NXP LPC18xx/43xx OTP memory NVMEM driver
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*
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* Copyright (c) 2016 Joachim Eastwood <manabian@gmail.com>
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*
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* Based on the imx ocotp driver,
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* Copyright (c) 2015 Pengutronix, Philipp Zabel <p.zabel@pengutronix.de>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2
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* as published by the Free Software Foundation.
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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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.owner = THIS_MODULE,
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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 = nvmem_register(&lpc18xx_otp_nvmem_config);
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if (IS_ERR(nvmem))
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return PTR_ERR(nvmem);
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platform_set_drvdata(pdev, nvmem);
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return 0;
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}
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static int lpc18xx_otp_remove(struct platform_device *pdev)
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{
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struct nvmem_device *nvmem = platform_get_drvdata(pdev);
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return nvmem_unregister(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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.remove = lpc18xx_otp_remove,
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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 <manabian@gmail.com>");
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MODULE_DESCRIPTION("NXP LPC18xx OTP NVMEM driver");
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MODULE_LICENSE("GPL v2");
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