char/hw_random/mtk-rng.c

1 // SPDX-License-Identifier: GPL-2.0-or-later
33 #define to_mtk_rng(p)	container_of(p, struct mtk_rng, rng)
38 	struct hwrng rng;
42 static int mtk_rng_init(struct hwrng *rng)
44 	struct mtk_rng *priv = to_mtk_rng(rng);
48 	err = clk_prepare_enable(priv->clk);
52 	val = readl(priv->base + RNG_CTRL);
54 	writel(val, priv->base + RNG_CTRL);
59 static void mtk_rng_cleanup(struct hwrng *rng)
61 	struct mtk_rng *priv = to_mtk_rng(rng);
64 	val = readl(priv->base + RNG_CTRL);
66 	writel(val, priv->base + RNG_CTRL);
68 	clk_disable_unprepare(priv->clk);
71 static bool mtk_rng_wait_ready(struct hwrng *rng, bool wait)
73 	struct mtk_rng *priv = to_mtk_rng(rng);
76 	ready = readl(priv->base + RNG_CTRL) & RNG_READY;
78 		readl_poll_timeout_atomic(priv->base + RNG_CTRL, ready,
84 static int mtk_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait)
86 	struct mtk_rng *priv = to_mtk_rng(rng);
89 	pm_runtime_get_sync(priv->dev);
92 		if (!mtk_rng_wait_ready(rng, wait))
95 		*(u32 *)buf = readl(priv->base + RNG_DATA);
98 		max -= sizeof(u32);
101 	pm_runtime_put_sync_autosuspend(priv->dev);
103 	return retval || !wait ? retval : -EIO;
111 	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
113 		return -ENOMEM;
115 	priv->dev = &pdev->dev;
116 	priv->rng.name = pdev->name;
118 	priv->rng.init = mtk_rng_init;
119 	priv->rng.cleanup = mtk_rng_cleanup;
121 	priv->rng.read = mtk_rng_read;
122 	priv->rng.quality = 900;
124 	priv->clk = devm_clk_get(&pdev->dev, "rng");
125 	if (IS_ERR(priv->clk)) {
126 		ret = PTR_ERR(priv->clk);
127 		dev_err(&pdev->dev, "no clock for device: %d\n", ret);
131 	priv->base = devm_platform_ioremap_resource(pdev, 0);
132 	if (IS_ERR(priv->base))
133 		return PTR_ERR(priv->base);
135 	ret = devm_hwrng_register(&pdev->dev, &priv->rng);
137 		dev_err(&pdev->dev, "failed to register rng device: %d\n",
142 	dev_set_drvdata(&pdev->dev, priv);
143 	pm_runtime_set_autosuspend_delay(&pdev->dev, RNG_AUTOSUSPEND_TIMEOUT);
144 	pm_runtime_use_autosuspend(&pdev->dev);
145 	ret = devm_pm_runtime_enable(&pdev->dev);
149 	dev_info(&pdev->dev, "registered RNG driver\n");
159 	mtk_rng_cleanup(&priv->rng);
168 	return mtk_rng_init(&priv->rng);
184 	{ .compatible = "mediatek,mt7986-rng" },
185 	{ .compatible = "mediatek,mt7623-rng" },