/* * drivers/char/hw_random/omap-rng.c * * RNG driver for TI OMAP CPU family * * Author: Deepak Saxena <dsaxena@plexity.net> * * Copyright 2005 (c) MontaVista Software, Inc. * * Mostly based on original driver: * * Copyright (C) 2005 Nokia Corporation * Author: Juha Yrj��<juha.yrjola@nokia.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. * * TODO: * * - Make status updated be interrupt driven so we don't poll * */ #include <linux/module.h> #include <linux/init.h> #include <linux/random.h> #include <linux/clk.h> #include <linux/err.h> #include <linux/platform_device.h> #include <linux/hw_random.h> #include <asm/io.h> #define RNG_OUT_REG 0x00 /* Output register */ #define RNG_STAT_REG 0x04 /* Status register [0] = STAT_BUSY */ #define RNG_ALARM_REG 0x24 /* Alarm register [7:0] = ALARM_COUNTER */ #define RNG_CONFIG_REG 0x28 /* Configuration register [11:6] = RESET_COUNT [5:3] = RING2_DELAY [2:0] = RING1_DELAY */ #define RNG_REV_REG 0x3c /* Revision register [7:0] = REV_NB */ #define RNG_MASK_REG 0x40 /* Mask and reset register [2] = IT_EN [1] = SOFTRESET [0] = AUTOIDLE */ #define RNG_SYSSTATUS 0x44 /* System status [0] = RESETDONE */ static void __iomem *rng_base; static struct clk *rng_ick; static struct platform_device *rng_dev; static u32 omap_rng_read_reg(int reg) { return __raw_readl(rng_base + reg); } static void omap_rng_write_reg(int reg, u32 val) { __raw_writel(val, rng_base + reg); } /* REVISIT: Does the status bit really work on 16xx? */ static int omap_rng_data_present(struct hwrng *rng) { return omap_rng_read_reg(RNG_STAT_REG) ? 0 : 1; } static int omap_rng_data_read(struct hwrng *rng, u32 *data) { *data = omap_rng_read_reg(RNG_OUT_REG); return 4; } static struct hwrng omap_rng_ops = { .name = "omap", .data_present = omap_rng_data_present, .data_read = omap_rng_data_read, }; static int __init omap_rng_probe(struct platform_device *pdev) { struct resource *res, *mem; int ret; /* * A bit ugly, and it will never actually happen but there can * be only one RNG and this catches any bork */ BUG_ON(rng_dev); if (cpu_is_omap24xx()) { rng_ick = clk_get(NULL, "rng_ick"); if (IS_ERR(rng_ick)) { dev_err(&pdev->dev, "Could not get rng_ick\n"); ret = PTR_ERR(rng_ick); return ret; } else clk_enable(rng_ick); } res = platform_get_resource(pdev, IORESOURCE_MEM, 0); if (!res) return -ENOENT; mem = request_mem_region(res->start, res->end - res->start + 1, pdev->name); if (mem == NULL) return -EBUSY; dev_set_drvdata(&pdev->dev, mem); rng_base = (u32 __iomem *)io_p2v(res->start); ret = hwrng_register(&omap_rng_ops); if (ret) { release_resource(mem); rng_base = NULL; return ret; } dev_info(&pdev->dev, "OMAP Random Number Generator ver. %02x\n", omap_rng_read_reg(RNG_REV_REG)); omap_rng_write_reg(RNG_MASK_REG, 0x1); rng_dev = pdev; return 0; } static int __exit omap_rng_remove(struct platform_device *pdev) { struct resource *mem = dev_get_drvdata(&pdev->dev); hwrng_unregister(&omap_rng_ops); omap_rng_write_reg(RNG_MASK_REG, 0x0); if (cpu_is_omap24xx()) { clk_disable(rng_ick); clk_put(rng_ick); } release_resource(mem); rng_base = NULL; return 0; } #ifdef CONFIG_PM static int omap_rng_suspend(struct platform_device *pdev, pm_message_t message) { omap_rng_write_reg(RNG_MASK_REG, 0x0); return 0; } static int omap_rng_resume(struct platform_device *pdev) { omap_rng_write_reg(RNG_MASK_REG, 0x1); return 0; } #else #define omap_rng_suspend NULL #define omap_rng_resume NULL #endif static struct platform_driver omap_rng_driver = { .driver = { .name = "omap_rng", .owner = THIS_MODULE, }, .probe = omap_rng_probe, .remove = __exit_p(omap_rng_remove), .suspend = omap_rng_suspend, .resume = omap_rng_resume }; static int __init omap_rng_init(void) { if (!cpu_is_omap16xx() && !cpu_is_omap24xx()) return -ENODEV; return platform_driver_register(&omap_rng_driver); } static void __exit omap_rng_exit(void) { platform_driver_unregister(&omap_rng_driver); } module_init(omap_rng_init); module_exit(omap_rng_exit); MODULE_AUTHOR("Deepak Saxena (and others)"); MODULE_LICENSE("GPL");