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195 lines
4.3 KiB
195 lines
4.3 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* Driver for Mediatek Hardware Random Number Generator |
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* |
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* Copyright (C) 2017 Sean Wang <[email protected]> |
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*/ |
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#define MTK_RNG_DEV KBUILD_MODNAME |
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#include <linux/clk.h> |
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#include <linux/delay.h> |
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#include <linux/err.h> |
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#include <linux/hw_random.h> |
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#include <linux/io.h> |
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#include <linux/iopoll.h> |
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#include <linux/kernel.h> |
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#include <linux/module.h> |
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#include <linux/of.h> |
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#include <linux/platform_device.h> |
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#include <linux/pm_runtime.h> |
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/* Runtime PM autosuspend timeout: */ |
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#define RNG_AUTOSUSPEND_TIMEOUT 100 |
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#define USEC_POLL 2 |
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#define TIMEOUT_POLL 20 |
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#define RNG_CTRL 0x00 |
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#define RNG_EN BIT(0) |
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#define RNG_READY BIT(31) |
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#define RNG_DATA 0x08 |
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#define to_mtk_rng(p) container_of(p, struct mtk_rng, rng) |
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struct mtk_rng { |
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void __iomem *base; |
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struct clk *clk; |
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struct hwrng rng; |
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}; |
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static int mtk_rng_init(struct hwrng *rng) |
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{ |
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struct mtk_rng *priv = to_mtk_rng(rng); |
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u32 val; |
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int err; |
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err = clk_prepare_enable(priv->clk); |
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if (err) |
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return err; |
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val = readl(priv->base + RNG_CTRL); |
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val |= RNG_EN; |
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writel(val, priv->base + RNG_CTRL); |
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return 0; |
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} |
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static void mtk_rng_cleanup(struct hwrng *rng) |
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{ |
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struct mtk_rng *priv = to_mtk_rng(rng); |
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u32 val; |
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val = readl(priv->base + RNG_CTRL); |
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val &= ~RNG_EN; |
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writel(val, priv->base + RNG_CTRL); |
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clk_disable_unprepare(priv->clk); |
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} |
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static bool mtk_rng_wait_ready(struct hwrng *rng, bool wait) |
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{ |
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struct mtk_rng *priv = to_mtk_rng(rng); |
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int ready; |
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ready = readl(priv->base + RNG_CTRL) & RNG_READY; |
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if (!ready && wait) |
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readl_poll_timeout_atomic(priv->base + RNG_CTRL, ready, |
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ready & RNG_READY, USEC_POLL, |
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TIMEOUT_POLL); |
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return !!ready; |
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} |
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static int mtk_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait) |
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{ |
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struct mtk_rng *priv = to_mtk_rng(rng); |
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int retval = 0; |
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pm_runtime_get_sync((struct device *)priv->rng.priv); |
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while (max >= sizeof(u32)) { |
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if (!mtk_rng_wait_ready(rng, wait)) |
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break; |
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*(u32 *)buf = readl(priv->base + RNG_DATA); |
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retval += sizeof(u32); |
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buf += sizeof(u32); |
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max -= sizeof(u32); |
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} |
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pm_runtime_mark_last_busy((struct device *)priv->rng.priv); |
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pm_runtime_put_sync_autosuspend((struct device *)priv->rng.priv); |
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return retval || !wait ? retval : -EIO; |
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} |
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static int mtk_rng_probe(struct platform_device *pdev) |
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{ |
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int ret; |
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struct mtk_rng *priv; |
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priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL); |
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if (!priv) |
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return -ENOMEM; |
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priv->rng.name = pdev->name; |
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#ifndef CONFIG_PM |
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priv->rng.init = mtk_rng_init; |
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priv->rng.cleanup = mtk_rng_cleanup; |
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#endif |
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priv->rng.read = mtk_rng_read; |
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priv->rng.priv = (unsigned long)&pdev->dev; |
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priv->rng.quality = 900; |
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priv->clk = devm_clk_get(&pdev->dev, "rng"); |
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if (IS_ERR(priv->clk)) { |
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ret = PTR_ERR(priv->clk); |
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dev_err(&pdev->dev, "no clock for device: %d\n", ret); |
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return ret; |
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} |
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priv->base = devm_platform_ioremap_resource(pdev, 0); |
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if (IS_ERR(priv->base)) |
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return PTR_ERR(priv->base); |
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ret = devm_hwrng_register(&pdev->dev, &priv->rng); |
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if (ret) { |
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dev_err(&pdev->dev, "failed to register rng device: %d\n", |
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ret); |
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return ret; |
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} |
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dev_set_drvdata(&pdev->dev, priv); |
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pm_runtime_set_autosuspend_delay(&pdev->dev, RNG_AUTOSUSPEND_TIMEOUT); |
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pm_runtime_use_autosuspend(&pdev->dev); |
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pm_runtime_enable(&pdev->dev); |
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dev_info(&pdev->dev, "registered RNG driver\n"); |
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return 0; |
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} |
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#ifdef CONFIG_PM |
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static int mtk_rng_runtime_suspend(struct device *dev) |
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{ |
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struct mtk_rng *priv = dev_get_drvdata(dev); |
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mtk_rng_cleanup(&priv->rng); |
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return 0; |
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} |
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static int mtk_rng_runtime_resume(struct device *dev) |
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{ |
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struct mtk_rng *priv = dev_get_drvdata(dev); |
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return mtk_rng_init(&priv->rng); |
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} |
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static UNIVERSAL_DEV_PM_OPS(mtk_rng_pm_ops, mtk_rng_runtime_suspend, |
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mtk_rng_runtime_resume, NULL); |
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#define MTK_RNG_PM_OPS (&mtk_rng_pm_ops) |
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#else /* CONFIG_PM */ |
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#define MTK_RNG_PM_OPS NULL |
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#endif /* CONFIG_PM */ |
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static const struct of_device_id mtk_rng_match[] = { |
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{ .compatible = "mediatek,mt7623-rng" }, |
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{}, |
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}; |
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MODULE_DEVICE_TABLE(of, mtk_rng_match); |
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static struct platform_driver mtk_rng_driver = { |
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.probe = mtk_rng_probe, |
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.driver = { |
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.name = MTK_RNG_DEV, |
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.pm = MTK_RNG_PM_OPS, |
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.of_match_table = mtk_rng_match, |
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}, |
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}; |
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module_platform_driver(mtk_rng_driver); |
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MODULE_DESCRIPTION("Mediatek Random Number Generator Driver"); |
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MODULE_AUTHOR("Sean Wang <[email protected]>"); |
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MODULE_LICENSE("GPL");
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