2 * omap-rng.c - RNG driver for TI OMAP CPU family
4 * Author: Deepak Saxena <dsaxena@plexity.net>
6 * Copyright 2005 (c) MontaVista Software, Inc.
8 * Mostly based on original driver:
10 * Copyright (C) 2005 Nokia Corporation
11 * Author: Juha Yrjölä <juha.yrjola@nokia.com>
13 * This file is licensed under the terms of the GNU General Public
14 * License version 2. This program is licensed "as is" without any
15 * warranty of any kind, whether express or implied.
18 #include <linux/module.h>
19 #include <linux/init.h>
20 #include <linux/random.h>
21 #include <linux/err.h>
22 #include <linux/platform_device.h>
23 #include <linux/hw_random.h>
24 #include <linux/delay.h>
25 #include <linux/slab.h>
26 #include <linux/pm_runtime.h>
30 #define RNG_OUT_REG 0x00 /* Output register */
31 #define RNG_STAT_REG 0x04 /* Status register
33 #define RNG_ALARM_REG 0x24 /* Alarm register
34 [7:0] = ALARM_COUNTER */
35 #define RNG_CONFIG_REG 0x28 /* Configuration register
38 [2:0] = RING1_DELAY */
39 #define RNG_REV_REG 0x3c /* Revision register
41 #define RNG_MASK_REG 0x40 /* Mask and reset register
45 #define RNG_SYSSTATUS 0x44 /* System status
49 * struct omap_rng_private_data - RNG IP block-specific data
50 * @base: virtual address of the beginning of the RNG IP block registers
51 * @mem_res: struct resource * for the IP block registers physical memory
53 struct omap_rng_private_data {
55 struct resource *mem_res;
58 static inline u32 omap_rng_read_reg(struct omap_rng_private_data *priv, int reg)
60 return __raw_readl(priv->base + reg);
63 static inline void omap_rng_write_reg(struct omap_rng_private_data *priv,
66 __raw_writel(val, priv->base + reg);
69 static int omap_rng_data_present(struct hwrng *rng, int wait)
71 struct omap_rng_private_data *priv;
74 priv = (struct omap_rng_private_data *)rng->priv;
76 for (i = 0; i < 20; i++) {
77 data = omap_rng_read_reg(priv, RNG_STAT_REG) ? 0 : 1;
80 /* RNG produces data fast enough (2+ MBit/sec, even
81 * during "rngtest" loads, that these delays don't
82 * seem to trigger. We *could* use the RNG IRQ, but
83 * that'd be higher overhead ... so why bother?
90 static int omap_rng_data_read(struct hwrng *rng, u32 *data)
92 struct omap_rng_private_data *priv;
94 priv = (struct omap_rng_private_data *)rng->priv;
96 *data = omap_rng_read_reg(priv, RNG_OUT_REG);
101 static struct hwrng omap_rng_ops = {
103 .data_present = omap_rng_data_present,
104 .data_read = omap_rng_data_read,
107 static int omap_rng_probe(struct platform_device *pdev)
109 struct omap_rng_private_data *priv;
112 priv = devm_kzalloc(&pdev->dev, sizeof(struct omap_rng_private_data),
115 dev_err(&pdev->dev, "could not allocate memory\n");
119 omap_rng_ops.priv = (unsigned long)priv;
120 platform_set_drvdata(pdev, priv);
122 priv->mem_res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
123 priv->base = devm_ioremap_resource(&pdev->dev, priv->mem_res);
124 if (IS_ERR(priv->base)) {
125 ret = PTR_ERR(priv->base);
128 platform_set_drvdata(pdev, priv);
130 pm_runtime_enable(&pdev->dev);
131 pm_runtime_get_sync(&pdev->dev);
133 ret = hwrng_register(&omap_rng_ops);
137 dev_info(&pdev->dev, "OMAP Random Number Generator ver. %02x\n",
138 omap_rng_read_reg(priv, RNG_REV_REG));
140 omap_rng_write_reg(priv, RNG_MASK_REG, 0x1);
146 pm_runtime_disable(&pdev->dev);
151 static int __exit omap_rng_remove(struct platform_device *pdev)
153 struct omap_rng_private_data *priv = platform_get_drvdata(pdev);
155 hwrng_unregister(&omap_rng_ops);
157 omap_rng_write_reg(priv, RNG_MASK_REG, 0x0);
159 pm_runtime_put_sync(&pdev->dev);
160 pm_runtime_disable(&pdev->dev);
165 #ifdef CONFIG_PM_SLEEP
167 static int omap_rng_suspend(struct device *dev)
169 struct omap_rng_private_data *priv = dev_get_drvdata(dev);
171 omap_rng_write_reg(priv, RNG_MASK_REG, 0x0);
172 pm_runtime_put_sync(dev);
177 static int omap_rng_resume(struct device *dev)
179 struct omap_rng_private_data *priv = dev_get_drvdata(dev);
181 pm_runtime_get_sync(dev);
182 omap_rng_write_reg(priv, RNG_MASK_REG, 0x1);
187 static SIMPLE_DEV_PM_OPS(omap_rng_pm, omap_rng_suspend, omap_rng_resume);
188 #define OMAP_RNG_PM (&omap_rng_pm)
192 #define OMAP_RNG_PM NULL
196 static struct platform_driver omap_rng_driver = {
199 .owner = THIS_MODULE,
202 .probe = omap_rng_probe,
203 .remove = __exit_p(omap_rng_remove),
206 module_platform_driver(omap_rng_driver);
207 MODULE_ALIAS("platform:omap_rng");
208 MODULE_AUTHOR("Deepak Saxena (and others)");
209 MODULE_LICENSE("GPL");