1/*
  2 * Broadcom BCM63xx Random Number Generator support
  3 *
  4 * Copyright (C) 2011, Florian Fainelli <florian@openwrt.org>
  5 * Copyright (C) 2009, Broadcom Corporation
  6 *
  7 */
  8#include <linux/module.h>
  9#include <linux/slab.h>
 10#include <linux/io.h>
 11#include <linux/err.h>
 12#include <linux/clk.h>
 13#include <linux/platform_device.h>
 14#include <linux/hw_random.h>
 15#include <linux/of.h>
 16
 17#define RNG_CTRL			0x00
 18#define RNG_EN				(1 << 0)
 19
 20#define RNG_STAT			0x04
 21#define RNG_AVAIL_MASK			(0xff000000)
 22
 23#define RNG_DATA			0x08
 24#define RNG_THRES			0x0c
 25#define RNG_MASK			0x10
 26
 27struct bcm63xx_rng_priv {
 28	struct hwrng rng;
 29	struct clk *clk;
 30	void __iomem *regs;
 31};
 32
 33#define to_rng_priv(rng)	container_of(rng, struct bcm63xx_rng_priv, rng)
 34
 35static int bcm63xx_rng_init(struct hwrng *rng)
 36{
 37	struct bcm63xx_rng_priv *priv = to_rng_priv(rng);
 38	u32 val;
 39	int error;
 40
 41	error = clk_prepare_enable(priv->clk);
 42	if (error)
 43		return error;
 44
 45	val = __raw_readl(priv->regs + RNG_CTRL);
 46	val |= RNG_EN;
 47	__raw_writel(val, priv->regs + RNG_CTRL);
 48
 49	return 0;
 50}
 51
 52static void bcm63xx_rng_cleanup(struct hwrng *rng)
 53{
 54	struct bcm63xx_rng_priv *priv = to_rng_priv(rng);
 55	u32 val;
 56
 57	val = __raw_readl(priv->regs + RNG_CTRL);
 58	val &= ~RNG_EN;
 59	__raw_writel(val, priv->regs + RNG_CTRL);
 60
 61	clk_disable_unprepare(priv->clk);
 62}
 63
 64static int bcm63xx_rng_data_present(struct hwrng *rng, int wait)
 65{
 66	struct bcm63xx_rng_priv *priv = to_rng_priv(rng);
 67
 68	return __raw_readl(priv->regs + RNG_STAT) & RNG_AVAIL_MASK;
 69}
 70
 71static int bcm63xx_rng_data_read(struct hwrng *rng, u32 *data)
 72{
 73	struct bcm63xx_rng_priv *priv = to_rng_priv(rng);
 74
 75	*data = __raw_readl(priv->regs + RNG_DATA);
 76
 77	return 4;
 78}
 79
 80static int bcm63xx_rng_probe(struct platform_device *pdev)
 81{
 82	struct resource *r;
 83	int ret;
 84	struct bcm63xx_rng_priv *priv;
 85
 86	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 87	if (!r) {
 88		dev_err(&pdev->dev, "no iomem resource\n");
 89		return -ENXIO;
 90	}
 91
 92	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
 93	if (!priv)
 94		return -ENOMEM;
 95
 96	priv->rng.name = pdev->name;
 97	priv->rng.init = bcm63xx_rng_init;
 98	priv->rng.cleanup = bcm63xx_rng_cleanup;
 99	priv->rng.data_present = bcm63xx_rng_data_present;
100	priv->rng.data_read = bcm63xx_rng_data_read;
101
102	priv->clk = devm_clk_get(&pdev->dev, "ipsec");
103	if (IS_ERR(priv->clk)) {
104		ret = PTR_ERR(priv->clk);
105		dev_err(&pdev->dev, "no clock for device: %d\n", ret);
106		return ret;
107	}
108
109	if (!devm_request_mem_region(&pdev->dev, r->start,
110					resource_size(r), pdev->name)) {
111		dev_err(&pdev->dev, "request mem failed");
112		return -EBUSY;
113	}
114
115	priv->regs = devm_ioremap_nocache(&pdev->dev, r->start,
116					resource_size(r));
117	if (!priv->regs) {
118		dev_err(&pdev->dev, "ioremap failed");
119		return -ENOMEM;
120	}
121
122	ret = devm_hwrng_register(&pdev->dev, &priv->rng);
123	if (ret) {
124		dev_err(&pdev->dev, "failed to register rng device: %d\n",
125			ret);
126		return ret;
127	}
128
129	dev_info(&pdev->dev, "registered RNG driver\n");
130
131	return 0;
132}
133
134#ifdef CONFIG_OF
135static const struct of_device_id bcm63xx_rng_of_match[] = {
136	{ .compatible = "brcm,bcm6368-rng", },
137	{},
138};
139MODULE_DEVICE_TABLE(of, bcm63xx_rng_of_match);
140#endif
141
142static struct platform_driver bcm63xx_rng_driver = {
143	.probe		= bcm63xx_rng_probe,
144	.driver		= {
145		.name	= "bcm63xx-rng",
146		.of_match_table = of_match_ptr(bcm63xx_rng_of_match),
147	},
148};
149
150module_platform_driver(bcm63xx_rng_driver);
151
152MODULE_AUTHOR("Florian Fainelli <florian@openwrt.org>");
153MODULE_DESCRIPTION("Broadcom BCM63xx RNG driver");
154MODULE_LICENSE("GPL");