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1/*2 * omap3-rom-rng.c - RNG driver for TI OMAP3 CPU family3 *4 * Copyright (C) 2009 Nokia Corporation5 * Author: Juha Yrjola <juha.yrjola@solidboot.com>6 *7 * Copyright (C) 2013 Pali Rohár <pali@kernel.org>8 *9 * This file is licensed under the terms of the GNU General Public10 * License version 2. This program is licensed "as is" without any11 * warranty of any kind, whether express or implied.12 */13 14#include <linux/module.h>15#include <linux/init.h>16#include <linux/random.h>17#include <linux/hw_random.h>18#include <linux/workqueue.h>19#include <linux/clk.h>20#include <linux/err.h>21#include <linux/io.h>22#include <linux/of.h>23#include <linux/platform_device.h>24#include <linux/pm_runtime.h>25 26#define RNG_RESET 0x0127#define RNG_GEN_PRNG_HW_INIT 0x0228#define RNG_GEN_HW 0x0829 30struct omap_rom_rng {31 struct clk *clk;32 struct device *dev;33 struct hwrng ops;34 u32 (*rom_rng_call)(u32 ptr, u32 count, u32 flag);35};36 37static int omap3_rom_rng_read(struct hwrng *rng, void *data, size_t max, bool w)38{39 struct omap_rom_rng *ddata;40 u32 ptr;41 int r;42 43 ddata = (struct omap_rom_rng *)rng->priv;44 45 r = pm_runtime_get_sync(ddata->dev);46 if (r < 0) {47 pm_runtime_put_noidle(ddata->dev);48 49 return r;50 }51 52 ptr = virt_to_phys(data);53 r = ddata->rom_rng_call(ptr, 4, RNG_GEN_HW);54 if (r != 0)55 r = -EINVAL;56 else57 r = 4;58 59 pm_runtime_mark_last_busy(ddata->dev);60 pm_runtime_put_autosuspend(ddata->dev);61 62 return r;63}64 65static int __maybe_unused omap_rom_rng_runtime_suspend(struct device *dev)66{67 struct omap_rom_rng *ddata;68 int r;69 70 ddata = dev_get_drvdata(dev);71 72 r = ddata->rom_rng_call(0, 0, RNG_RESET);73 if (r != 0)74 dev_err(dev, "reset failed: %d\n", r);75 76 clk_disable_unprepare(ddata->clk);77 78 return 0;79}80 81static int __maybe_unused omap_rom_rng_runtime_resume(struct device *dev)82{83 struct omap_rom_rng *ddata;84 int r;85 86 ddata = dev_get_drvdata(dev);87 88 r = clk_prepare_enable(ddata->clk);89 if (r < 0)90 return r;91 92 r = ddata->rom_rng_call(0, 0, RNG_GEN_PRNG_HW_INIT);93 if (r != 0) {94 clk_disable_unprepare(ddata->clk);95 dev_err(dev, "HW init failed: %d\n", r);96 97 return -EIO;98 }99 100 return 0;101}102 103static void omap_rom_rng_finish(void *data)104{105 struct omap_rom_rng *ddata = data;106 107 pm_runtime_dont_use_autosuspend(ddata->dev);108 pm_runtime_disable(ddata->dev);109}110 111static int omap3_rom_rng_probe(struct platform_device *pdev)112{113 struct omap_rom_rng *ddata;114 int ret = 0;115 116 ddata = devm_kzalloc(&pdev->dev, sizeof(*ddata), GFP_KERNEL);117 if (!ddata)118 return -ENOMEM;119 120 ddata->dev = &pdev->dev;121 ddata->ops.priv = (unsigned long)ddata;122 ddata->ops.name = "omap3-rom";123 ddata->ops.read = of_device_get_match_data(&pdev->dev);124 ddata->ops.quality = 900;125 if (!ddata->ops.read) {126 dev_err(&pdev->dev, "missing rom code handler\n");127 128 return -ENODEV;129 }130 dev_set_drvdata(ddata->dev, ddata);131 132 ddata->rom_rng_call = pdev->dev.platform_data;133 if (!ddata->rom_rng_call) {134 dev_err(ddata->dev, "rom_rng_call is NULL\n");135 return -EINVAL;136 }137 138 ddata->clk = devm_clk_get(ddata->dev, "ick");139 if (IS_ERR(ddata->clk)) {140 dev_err(ddata->dev, "unable to get RNG clock\n");141 return PTR_ERR(ddata->clk);142 }143 144 pm_runtime_enable(&pdev->dev);145 pm_runtime_set_autosuspend_delay(&pdev->dev, 500);146 pm_runtime_use_autosuspend(&pdev->dev);147 148 ret = devm_add_action_or_reset(ddata->dev, omap_rom_rng_finish,149 ddata);150 if (ret)151 return ret;152 153 return devm_hwrng_register(ddata->dev, &ddata->ops);154}155 156static const struct of_device_id omap_rom_rng_match[] = {157 { .compatible = "nokia,n900-rom-rng", .data = omap3_rom_rng_read, },158 { /* sentinel */ },159};160MODULE_DEVICE_TABLE(of, omap_rom_rng_match);161 162static const struct dev_pm_ops omap_rom_rng_pm_ops = {163 SET_SYSTEM_SLEEP_PM_OPS(omap_rom_rng_runtime_suspend,164 omap_rom_rng_runtime_resume)165};166 167static struct platform_driver omap3_rom_rng_driver = {168 .driver = {169 .name = "omap3-rom-rng",170 .of_match_table = omap_rom_rng_match,171 .pm = &omap_rom_rng_pm_ops,172 },173 .probe = omap3_rom_rng_probe,174};175 176module_platform_driver(omap3_rom_rng_driver);177 178MODULE_ALIAS("platform:omap3-rom-rng");179MODULE_AUTHOR("Juha Yrjola");180MODULE_AUTHOR("Pali Rohár <pali@kernel.org>");181MODULE_DESCRIPTION("RNG driver for TI OMAP3 CPU family");182MODULE_LICENSE("GPL");183