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1// SPDX-License-Identifier: GPL-2.02// Copyright (c) 2019 Nuvoton Technology corporation.3 4#include <linux/kernel.h>5#include <linux/module.h>6#include <linux/io.h>7#include <linux/iopoll.h>8#include <linux/init.h>9#include <linux/random.h>10#include <linux/err.h>11#include <linux/of.h>12#include <linux/platform_device.h>13#include <linux/hw_random.h>14#include <linux/delay.h>15#include <linux/pm_runtime.h>16 17#define NPCM_RNGCS_REG 0x00 /* Control and status register */18#define NPCM_RNGD_REG 0x04 /* Data register */19#define NPCM_RNGMODE_REG 0x08 /* Mode register */20 21#define NPCM_RNG_CLK_SET_62_5MHZ BIT(2) /* 60-80 MHz */22#define NPCM_RNG_CLK_SET_25MHZ GENMASK(4, 3) /* 20-25 MHz */23#define NPCM_RNG_DATA_VALID BIT(1)24#define NPCM_RNG_ENABLE BIT(0)25#define NPCM_RNG_M1ROSEL BIT(1)26 27#define NPCM_RNG_TIMEOUT_USEC 2000028#define NPCM_RNG_POLL_USEC 100029 30#define to_npcm_rng(p) container_of(p, struct npcm_rng, rng)31 32struct npcm_rng {33 void __iomem *base;34 struct hwrng rng;35 u32 clkp;36};37 38static int npcm_rng_init(struct hwrng *rng)39{40 struct npcm_rng *priv = to_npcm_rng(rng);41 42 writel(priv->clkp | NPCM_RNG_ENABLE, priv->base + NPCM_RNGCS_REG);43 44 return 0;45}46 47static void npcm_rng_cleanup(struct hwrng *rng)48{49 struct npcm_rng *priv = to_npcm_rng(rng);50 51 writel(priv->clkp, priv->base + NPCM_RNGCS_REG);52}53 54static int npcm_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait)55{56 struct npcm_rng *priv = to_npcm_rng(rng);57 int retval = 0;58 int ready;59 60 pm_runtime_get_sync((struct device *)priv->rng.priv);61 62 while (max) {63 if (wait) {64 if (readb_poll_timeout(priv->base + NPCM_RNGCS_REG,65 ready,66 ready & NPCM_RNG_DATA_VALID,67 NPCM_RNG_POLL_USEC,68 NPCM_RNG_TIMEOUT_USEC))69 break;70 } else {71 if ((readb(priv->base + NPCM_RNGCS_REG) &72 NPCM_RNG_DATA_VALID) == 0)73 break;74 }75 76 *(u8 *)buf = readb(priv->base + NPCM_RNGD_REG);77 retval++;78 buf++;79 max--;80 }81 82 pm_runtime_mark_last_busy((struct device *)priv->rng.priv);83 pm_runtime_put_sync_autosuspend((struct device *)priv->rng.priv);84 85 return retval || !wait ? retval : -EIO;86}87 88static int npcm_rng_probe(struct platform_device *pdev)89{90 struct npcm_rng *priv;91 int ret;92 93 priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);94 if (!priv)95 return -ENOMEM;96 97 priv->base = devm_platform_ioremap_resource(pdev, 0);98 if (IS_ERR(priv->base))99 return PTR_ERR(priv->base);100 101 dev_set_drvdata(&pdev->dev, priv);102 pm_runtime_set_autosuspend_delay(&pdev->dev, 100);103 pm_runtime_use_autosuspend(&pdev->dev);104 pm_runtime_enable(&pdev->dev);105 106#ifndef CONFIG_PM107 priv->rng.init = npcm_rng_init;108 priv->rng.cleanup = npcm_rng_cleanup;109#endif110 priv->rng.name = pdev->name;111 priv->rng.read = npcm_rng_read;112 priv->rng.priv = (unsigned long)&pdev->dev;113 priv->clkp = (u32)(uintptr_t)of_device_get_match_data(&pdev->dev);114 115 writel(NPCM_RNG_M1ROSEL, priv->base + NPCM_RNGMODE_REG);116 117 ret = devm_hwrng_register(&pdev->dev, &priv->rng);118 if (ret) {119 dev_err(&pdev->dev, "Failed to register rng device: %d\n",120 ret);121 pm_runtime_disable(&pdev->dev);122 pm_runtime_set_suspended(&pdev->dev);123 return ret;124 }125 126 return 0;127}128 129static void npcm_rng_remove(struct platform_device *pdev)130{131 struct npcm_rng *priv = platform_get_drvdata(pdev);132 133 devm_hwrng_unregister(&pdev->dev, &priv->rng);134 pm_runtime_disable(&pdev->dev);135 pm_runtime_set_suspended(&pdev->dev);136}137 138#ifdef CONFIG_PM139static int npcm_rng_runtime_suspend(struct device *dev)140{141 struct npcm_rng *priv = dev_get_drvdata(dev);142 143 npcm_rng_cleanup(&priv->rng);144 145 return 0;146}147 148static int npcm_rng_runtime_resume(struct device *dev)149{150 struct npcm_rng *priv = dev_get_drvdata(dev);151 152 return npcm_rng_init(&priv->rng);153}154#endif155 156static const struct dev_pm_ops npcm_rng_pm_ops = {157 SET_RUNTIME_PM_OPS(npcm_rng_runtime_suspend,158 npcm_rng_runtime_resume, NULL)159 SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,160 pm_runtime_force_resume)161};162 163static const struct of_device_id rng_dt_id[] __maybe_unused = {164 { .compatible = "nuvoton,npcm750-rng",165 .data = (void *)NPCM_RNG_CLK_SET_25MHZ },166 { .compatible = "nuvoton,npcm845-rng",167 .data = (void *)NPCM_RNG_CLK_SET_62_5MHZ },168 {},169};170MODULE_DEVICE_TABLE(of, rng_dt_id);171 172static struct platform_driver npcm_rng_driver = {173 .driver = {174 .name = "npcm-rng",175 .pm = &npcm_rng_pm_ops,176 .of_match_table = of_match_ptr(rng_dt_id),177 },178 .probe = npcm_rng_probe,179 .remove_new = npcm_rng_remove,180};181 182module_platform_driver(npcm_rng_driver);183 184MODULE_DESCRIPTION("Nuvoton NPCM Random Number Generator Driver");185MODULE_AUTHOR("Tomer Maimon <tomer.maimon@nuvoton.com>");186MODULE_LICENSE("GPL v2");187