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184 lines
4.3 KiB
184 lines
4.3 KiB
// SPDX-License-Identifier: GPL-2.0 |
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// Copyright (c) 2019 Nuvoton Technology corporation. |
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#include <linux/kernel.h> |
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#include <linux/module.h> |
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#include <linux/io.h> |
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#include <linux/iopoll.h> |
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#include <linux/init.h> |
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#include <linux/random.h> |
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#include <linux/err.h> |
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#include <linux/platform_device.h> |
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#include <linux/hw_random.h> |
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#include <linux/delay.h> |
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#include <linux/of_irq.h> |
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#include <linux/pm_runtime.h> |
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#define NPCM_RNGCS_REG 0x00 /* Control and status register */ |
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#define NPCM_RNGD_REG 0x04 /* Data register */ |
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#define NPCM_RNGMODE_REG 0x08 /* Mode register */ |
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#define NPCM_RNG_CLK_SET_25MHZ GENMASK(4, 3) /* 20-25 MHz */ |
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#define NPCM_RNG_DATA_VALID BIT(1) |
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#define NPCM_RNG_ENABLE BIT(0) |
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#define NPCM_RNG_M1ROSEL BIT(1) |
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#define NPCM_RNG_TIMEOUT_USEC 20000 |
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#define NPCM_RNG_POLL_USEC 1000 |
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#define to_npcm_rng(p) container_of(p, struct npcm_rng, rng) |
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struct npcm_rng { |
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void __iomem *base; |
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struct hwrng rng; |
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}; |
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static int npcm_rng_init(struct hwrng *rng) |
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{ |
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struct npcm_rng *priv = to_npcm_rng(rng); |
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writel(NPCM_RNG_CLK_SET_25MHZ | NPCM_RNG_ENABLE, |
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priv->base + NPCM_RNGCS_REG); |
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return 0; |
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} |
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static void npcm_rng_cleanup(struct hwrng *rng) |
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{ |
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struct npcm_rng *priv = to_npcm_rng(rng); |
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writel(NPCM_RNG_CLK_SET_25MHZ, priv->base + NPCM_RNGCS_REG); |
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} |
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static int npcm_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait) |
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{ |
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struct npcm_rng *priv = to_npcm_rng(rng); |
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int retval = 0; |
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int ready; |
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pm_runtime_get_sync((struct device *)priv->rng.priv); |
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while (max) { |
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if (wait) { |
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if (readb_poll_timeout(priv->base + NPCM_RNGCS_REG, |
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ready, |
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ready & NPCM_RNG_DATA_VALID, |
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NPCM_RNG_POLL_USEC, |
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NPCM_RNG_TIMEOUT_USEC)) |
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break; |
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} else { |
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if ((readb(priv->base + NPCM_RNGCS_REG) & |
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NPCM_RNG_DATA_VALID) == 0) |
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break; |
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} |
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*(u8 *)buf = readb(priv->base + NPCM_RNGD_REG); |
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retval++; |
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buf++; |
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max--; |
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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 npcm_rng_probe(struct platform_device *pdev) |
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{ |
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struct npcm_rng *priv; |
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int ret; |
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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->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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dev_set_drvdata(&pdev->dev, priv); |
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pm_runtime_set_autosuspend_delay(&pdev->dev, 100); |
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pm_runtime_use_autosuspend(&pdev->dev); |
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pm_runtime_enable(&pdev->dev); |
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#ifndef CONFIG_PM |
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priv->rng.init = npcm_rng_init; |
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priv->rng.cleanup = npcm_rng_cleanup; |
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#endif |
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priv->rng.name = pdev->name; |
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priv->rng.read = npcm_rng_read; |
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priv->rng.priv = (unsigned long)&pdev->dev; |
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priv->rng.quality = 1000; |
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writel(NPCM_RNG_M1ROSEL, priv->base + NPCM_RNGMODE_REG); |
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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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pm_runtime_disable(&pdev->dev); |
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pm_runtime_set_suspended(&pdev->dev); |
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return ret; |
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} |
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return 0; |
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} |
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static int npcm_rng_remove(struct platform_device *pdev) |
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{ |
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struct npcm_rng *priv = platform_get_drvdata(pdev); |
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devm_hwrng_unregister(&pdev->dev, &priv->rng); |
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pm_runtime_disable(&pdev->dev); |
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pm_runtime_set_suspended(&pdev->dev); |
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return 0; |
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} |
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#ifdef CONFIG_PM |
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static int npcm_rng_runtime_suspend(struct device *dev) |
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{ |
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struct npcm_rng *priv = dev_get_drvdata(dev); |
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npcm_rng_cleanup(&priv->rng); |
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return 0; |
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} |
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static int npcm_rng_runtime_resume(struct device *dev) |
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{ |
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struct npcm_rng *priv = dev_get_drvdata(dev); |
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return npcm_rng_init(&priv->rng); |
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} |
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#endif |
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static const struct dev_pm_ops npcm_rng_pm_ops = { |
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SET_RUNTIME_PM_OPS(npcm_rng_runtime_suspend, |
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npcm_rng_runtime_resume, NULL) |
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SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend, |
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pm_runtime_force_resume) |
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}; |
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static const struct of_device_id rng_dt_id[] __maybe_unused = { |
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{ .compatible = "nuvoton,npcm750-rng", }, |
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{}, |
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}; |
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MODULE_DEVICE_TABLE(of, rng_dt_id); |
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static struct platform_driver npcm_rng_driver = { |
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.driver = { |
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.name = "npcm-rng", |
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.pm = &npcm_rng_pm_ops, |
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.of_match_table = of_match_ptr(rng_dt_id), |
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}, |
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.probe = npcm_rng_probe, |
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.remove = npcm_rng_remove, |
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}; |
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module_platform_driver(npcm_rng_driver); |
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MODULE_DESCRIPTION("Nuvoton NPCM Random Number Generator Driver"); |
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MODULE_AUTHOR("Tomer Maimon <[email protected]>"); |
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MODULE_LICENSE("GPL v2");
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