omap3-rom-rng.rar_family

/* * 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");