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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 | /* * omap3-rom-rng.c - RNG driver for TI OMAP3 CPU family * * Copyright (C) 2009 Nokia Corporation * Author: Juha Yrjola <juha.yrjola@solidboot.com> * * Copyright (C) 2013 Pali Rohár <pali.rohar@gmail.com> * * This file is licensed under the terms of the GNU General Public * License version 2. This program is licensed "as is" without any * warranty of any kind, whether express or implied. */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include <linux/module.h> #include <linux/init.h> #include <linux/random.h> #include <linux/hw_random.h> #include <linux/timer.h> #include <linux/clk.h> #include <linux/err.h> #include <linux/platform_device.h> #define RNG_RESET 0x01 #define RNG_GEN_PRNG_HW_INIT 0x02 #define RNG_GEN_HW 0x08 /* param1: ptr, param2: count, param3: flag */ static u32 (*omap3_rom_rng_call)(u32, u32, u32); static struct timer_list idle_timer; static int rng_idle; static struct clk *rng_clk; static void omap3_rom_rng_idle(unsigned long data) { int r; r = omap3_rom_rng_call(0, 0, RNG_RESET); if (r != 0) { pr_err("reset failed: %d\n", r); return; } clk_disable_unprepare(rng_clk); rng_idle = 1; } static int omap3_rom_rng_get_random(void *buf, unsigned int count) { u32 r; u32 ptr; del_timer_sync(&idle_timer); if (rng_idle) { clk_prepare_enable(rng_clk); r = omap3_rom_rng_call(0, 0, RNG_GEN_PRNG_HW_INIT); if (r != 0) { clk_disable_unprepare(rng_clk); pr_err("HW init failed: %d\n", r); return -EIO; } rng_idle = 0; } ptr = virt_to_phys(buf); r = omap3_rom_rng_call(ptr, count, RNG_GEN_HW); mod_timer(&idle_timer, jiffies + msecs_to_jiffies(500)); if (r != 0) return -EINVAL; return 0; } static int omap3_rom_rng_data_present(struct hwrng *rng, int wait) { return 1; } static int omap3_rom_rng_data_read(struct hwrng *rng, u32 *data) { int r; r = omap3_rom_rng_get_random(data, 4); if (r < 0) return r; return 4; } static struct hwrng omap3_rom_rng_ops = { .name = "omap3-rom", .data_present = omap3_rom_rng_data_present, .data_read = omap3_rom_rng_data_read, }; static int omap3_rom_rng_probe(struct platform_device *pdev) { pr_info("initializing\n"); omap3_rom_rng_call = pdev->dev.platform_data; if (!omap3_rom_rng_call) { pr_err("omap3_rom_rng_call is NULL\n"); return -EINVAL; } setup_timer(&idle_timer, omap3_rom_rng_idle, 0); rng_clk = clk_get(&pdev->dev, "ick"); if (IS_ERR(rng_clk)) { pr_err("unable to get RNG clock\n"); return PTR_ERR(rng_clk); } /* Leave the RNG in reset state. */ clk_prepare_enable(rng_clk); omap3_rom_rng_idle(0); return hwrng_register(&omap3_rom_rng_ops); } static int omap3_rom_rng_remove(struct platform_device *pdev) { hwrng_unregister(&omap3_rom_rng_ops); clk_disable_unprepare(rng_clk); clk_put(rng_clk); return 0; } static struct platform_driver omap3_rom_rng_driver = { .driver = { .name = "omap3-rom-rng", .owner = THIS_MODULE, }, .probe = omap3_rom_rng_probe, .remove = omap3_rom_rng_remove, }; module_platform_driver(omap3_rom_rng_driver); MODULE_ALIAS("platform:omap3-rom-rng"); MODULE_AUTHOR("Juha Yrjola"); MODULE_AUTHOR("Pali Rohár <pali.rohar@gmail.com>"); MODULE_LICENSE("GPL"); |