| Joachim Eastwood | 88806daf | 2016-10-31 14:45:16 +0000 | [diff] [blame] | 1 | /* |
| 2 | * NXP LPC18xx/43xx OTP memory NVMEM driver |
| 3 | * |
| 4 | * Copyright (c) 2016 Joachim Eastwood <manabian@gmail.com> |
| 5 | * |
| 6 | * Based on the imx ocotp driver, |
| 7 | * Copyright (c) 2015 Pengutronix, Philipp Zabel <p.zabel@pengutronix.de> |
| 8 | * |
| 9 | * This program is free software; you can redistribute it and/or modify |
| 10 | * it under the terms of the GNU General Public License version 2 |
| 11 | * as published by the Free Software Foundation. |
| 12 | * |
| 13 | * TODO: add support for writing OTP register via API in boot ROM. |
| 14 | */ |
| 15 | |
| 16 | #include <linux/io.h> |
| 17 | #include <linux/module.h> |
| 18 | #include <linux/nvmem-provider.h> |
| 19 | #include <linux/of.h> |
| 20 | #include <linux/of_device.h> |
| 21 | #include <linux/platform_device.h> |
| 22 | #include <linux/slab.h> |
| 23 | |
| 24 | /* |
| 25 | * LPC18xx OTP memory contains 4 banks with 4 32-bit words. Bank 0 starts |
| 26 | * at offset 0 from the base. |
| 27 | * |
| 28 | * Bank 0 contains the part ID for Flashless devices and is reseverd for |
| 29 | * devices with Flash. |
| 30 | * Bank 1/2 is generale purpose or AES key storage for secure devices. |
| 31 | * Bank 3 contains control data, USB ID and generale purpose words. |
| 32 | */ |
| 33 | #define LPC18XX_OTP_NUM_BANKS 4 |
| 34 | #define LPC18XX_OTP_WORDS_PER_BANK 4 |
| 35 | #define LPC18XX_OTP_WORD_SIZE sizeof(u32) |
| 36 | #define LPC18XX_OTP_SIZE (LPC18XX_OTP_NUM_BANKS * \ |
| 37 | LPC18XX_OTP_WORDS_PER_BANK * \ |
| 38 | LPC18XX_OTP_WORD_SIZE) |
| 39 | |
| 40 | struct lpc18xx_otp { |
| 41 | void __iomem *base; |
| 42 | }; |
| 43 | |
| 44 | static int lpc18xx_otp_read(void *context, unsigned int offset, |
| 45 | void *val, size_t bytes) |
| 46 | { |
| 47 | struct lpc18xx_otp *otp = context; |
| 48 | unsigned int count = bytes >> 2; |
| 49 | u32 index = offset >> 2; |
| 50 | u32 *buf = val; |
| 51 | int i; |
| 52 | |
| 53 | if (count > (LPC18XX_OTP_SIZE - index)) |
| 54 | count = LPC18XX_OTP_SIZE - index; |
| 55 | |
| 56 | for (i = index; i < (index + count); i++) |
| 57 | *buf++ = readl(otp->base + i * LPC18XX_OTP_WORD_SIZE); |
| 58 | |
| 59 | return 0; |
| 60 | } |
| 61 | |
| 62 | static struct nvmem_config lpc18xx_otp_nvmem_config = { |
| 63 | .name = "lpc18xx-otp", |
| 64 | .read_only = true, |
| 65 | .word_size = LPC18XX_OTP_WORD_SIZE, |
| 66 | .stride = LPC18XX_OTP_WORD_SIZE, |
| 67 | .owner = THIS_MODULE, |
| 68 | .reg_read = lpc18xx_otp_read, |
| 69 | }; |
| 70 | |
| 71 | static int lpc18xx_otp_probe(struct platform_device *pdev) |
| 72 | { |
| 73 | struct nvmem_device *nvmem; |
| 74 | struct lpc18xx_otp *otp; |
| 75 | struct resource *res; |
| 76 | |
| 77 | otp = devm_kzalloc(&pdev->dev, sizeof(*otp), GFP_KERNEL); |
| 78 | if (!otp) |
| 79 | return -ENOMEM; |
| 80 | |
| 81 | res = platform_get_resource(pdev, IORESOURCE_MEM, 0); |
| 82 | otp->base = devm_ioremap_resource(&pdev->dev, res); |
| 83 | if (IS_ERR(otp->base)) |
| 84 | return PTR_ERR(otp->base); |
| 85 | |
| 86 | lpc18xx_otp_nvmem_config.size = LPC18XX_OTP_SIZE; |
| 87 | lpc18xx_otp_nvmem_config.dev = &pdev->dev; |
| 88 | lpc18xx_otp_nvmem_config.priv = otp; |
| 89 | |
| 90 | nvmem = nvmem_register(&lpc18xx_otp_nvmem_config); |
| 91 | if (IS_ERR(nvmem)) |
| 92 | return PTR_ERR(nvmem); |
| 93 | |
| 94 | platform_set_drvdata(pdev, nvmem); |
| 95 | |
| 96 | return 0; |
| 97 | } |
| 98 | |
| 99 | static int lpc18xx_otp_remove(struct platform_device *pdev) |
| 100 | { |
| 101 | struct nvmem_device *nvmem = platform_get_drvdata(pdev); |
| 102 | |
| 103 | return nvmem_unregister(nvmem); |
| 104 | } |
| 105 | |
| 106 | static const struct of_device_id lpc18xx_otp_dt_ids[] = { |
| 107 | { .compatible = "nxp,lpc1850-otp" }, |
| 108 | { }, |
| 109 | }; |
| 110 | MODULE_DEVICE_TABLE(of, lpc18xx_otp_dt_ids); |
| 111 | |
| 112 | static struct platform_driver lpc18xx_otp_driver = { |
| 113 | .probe = lpc18xx_otp_probe, |
| 114 | .remove = lpc18xx_otp_remove, |
| 115 | .driver = { |
| 116 | .name = "lpc18xx_otp", |
| 117 | .of_match_table = lpc18xx_otp_dt_ids, |
| 118 | }, |
| 119 | }; |
| 120 | module_platform_driver(lpc18xx_otp_driver); |
| 121 | |
| 122 | MODULE_AUTHOR("Joachim Eastwoood <manabian@gmail.com>"); |
| 123 | MODULE_DESCRIPTION("NXP LPC18xx OTP NVMEM driver"); |
| 124 | MODULE_LICENSE("GPL v2"); |