| // SPDX-License-Identifier: GPL-2.0 |
| // Copyright (c) 2019 Nuvoton Technology corporation. |
| |
| #include <linux/kernel.h> |
| #include <linux/module.h> |
| #include <linux/io.h> |
| #include <linux/iopoll.h> |
| #include <linux/init.h> |
| #include <linux/random.h> |
| #include <linux/err.h> |
| #include <linux/of.h> |
| #include <linux/platform_device.h> |
| #include <linux/hw_random.h> |
| #include <linux/delay.h> |
| #include <linux/pm_runtime.h> |
| |
| #define NPCM_RNGCS_REG 0x00 /* Control and status register */ |
| #define NPCM_RNGD_REG 0x04 /* Data register */ |
| #define NPCM_RNGMODE_REG 0x08 /* Mode register */ |
| |
| #define NPCM_RNG_CLK_SET_62_5MHZ BIT(2) /* 60-80 MHz */ |
| #define NPCM_RNG_CLK_SET_25MHZ GENMASK(4, 3) /* 20-25 MHz */ |
| #define NPCM_RNG_DATA_VALID BIT(1) |
| #define NPCM_RNG_ENABLE BIT(0) |
| #define NPCM_RNG_M1ROSEL BIT(1) |
| |
| #define NPCM_RNG_TIMEOUT_USEC 20000 |
| #define NPCM_RNG_POLL_USEC 1000 |
| |
| #define to_npcm_rng(p) container_of(p, struct npcm_rng, rng) |
| |
| struct npcm_rng { |
| void __iomem *base; |
| struct hwrng rng; |
| u32 clkp; |
| }; |
| |
| static int npcm_rng_init(struct hwrng *rng) |
| { |
| struct npcm_rng *priv = to_npcm_rng(rng); |
| |
| writel(priv->clkp | NPCM_RNG_ENABLE, priv->base + NPCM_RNGCS_REG); |
| |
| return 0; |
| } |
| |
| static void npcm_rng_cleanup(struct hwrng *rng) |
| { |
| struct npcm_rng *priv = to_npcm_rng(rng); |
| |
| writel(priv->clkp, priv->base + NPCM_RNGCS_REG); |
| } |
| |
| static int npcm_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait) |
| { |
| struct npcm_rng *priv = to_npcm_rng(rng); |
| int retval = 0; |
| int ready; |
| |
| pm_runtime_get_sync((struct device *)priv->rng.priv); |
| |
| while (max) { |
| if (wait) { |
| if (readb_poll_timeout(priv->base + NPCM_RNGCS_REG, |
| ready, |
| ready & NPCM_RNG_DATA_VALID, |
| NPCM_RNG_POLL_USEC, |
| NPCM_RNG_TIMEOUT_USEC)) |
| break; |
| } else { |
| if ((readb(priv->base + NPCM_RNGCS_REG) & |
| NPCM_RNG_DATA_VALID) == 0) |
| break; |
| } |
| |
| *(u8 *)buf = readb(priv->base + NPCM_RNGD_REG); |
| retval++; |
| buf++; |
| max--; |
| } |
| |
| pm_runtime_mark_last_busy((struct device *)priv->rng.priv); |
| pm_runtime_put_sync_autosuspend((struct device *)priv->rng.priv); |
| |
| return retval || !wait ? retval : -EIO; |
| } |
| |
| static int npcm_rng_probe(struct platform_device *pdev) |
| { |
| struct npcm_rng *priv; |
| int ret; |
| |
| priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL); |
| if (!priv) |
| return -ENOMEM; |
| |
| priv->base = devm_platform_ioremap_resource(pdev, 0); |
| if (IS_ERR(priv->base)) |
| return PTR_ERR(priv->base); |
| |
| dev_set_drvdata(&pdev->dev, priv); |
| pm_runtime_set_autosuspend_delay(&pdev->dev, 100); |
| pm_runtime_use_autosuspend(&pdev->dev); |
| pm_runtime_enable(&pdev->dev); |
| |
| #ifndef CONFIG_PM |
| priv->rng.init = npcm_rng_init; |
| priv->rng.cleanup = npcm_rng_cleanup; |
| #endif |
| priv->rng.name = pdev->name; |
| priv->rng.read = npcm_rng_read; |
| priv->rng.priv = (unsigned long)&pdev->dev; |
| priv->clkp = (u32)(uintptr_t)of_device_get_match_data(&pdev->dev); |
| |
| writel(NPCM_RNG_M1ROSEL, priv->base + NPCM_RNGMODE_REG); |
| |
| ret = devm_hwrng_register(&pdev->dev, &priv->rng); |
| if (ret) { |
| dev_err(&pdev->dev, "Failed to register rng device: %d\n", |
| ret); |
| pm_runtime_disable(&pdev->dev); |
| pm_runtime_set_suspended(&pdev->dev); |
| return ret; |
| } |
| |
| return 0; |
| } |
| |
| static int npcm_rng_remove(struct platform_device *pdev) |
| { |
| struct npcm_rng *priv = platform_get_drvdata(pdev); |
| |
| devm_hwrng_unregister(&pdev->dev, &priv->rng); |
| pm_runtime_disable(&pdev->dev); |
| pm_runtime_set_suspended(&pdev->dev); |
| |
| return 0; |
| } |
| |
| #ifdef CONFIG_PM |
| static int npcm_rng_runtime_suspend(struct device *dev) |
| { |
| struct npcm_rng *priv = dev_get_drvdata(dev); |
| |
| npcm_rng_cleanup(&priv->rng); |
| |
| return 0; |
| } |
| |
| static int npcm_rng_runtime_resume(struct device *dev) |
| { |
| struct npcm_rng *priv = dev_get_drvdata(dev); |
| |
| return npcm_rng_init(&priv->rng); |
| } |
| #endif |
| |
| static const struct dev_pm_ops npcm_rng_pm_ops = { |
| SET_RUNTIME_PM_OPS(npcm_rng_runtime_suspend, |
| npcm_rng_runtime_resume, NULL) |
| SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend, |
| pm_runtime_force_resume) |
| }; |
| |
| static const struct of_device_id rng_dt_id[] __maybe_unused = { |
| { .compatible = "nuvoton,npcm750-rng", |
| .data = (void *)NPCM_RNG_CLK_SET_25MHZ }, |
| { .compatible = "nuvoton,npcm845-rng", |
| .data = (void *)NPCM_RNG_CLK_SET_62_5MHZ }, |
| {}, |
| }; |
| MODULE_DEVICE_TABLE(of, rng_dt_id); |
| |
| static struct platform_driver npcm_rng_driver = { |
| .driver = { |
| .name = "npcm-rng", |
| .pm = &npcm_rng_pm_ops, |
| .of_match_table = of_match_ptr(rng_dt_id), |
| }, |
| .probe = npcm_rng_probe, |
| .remove = npcm_rng_remove, |
| }; |
| |
| module_platform_driver(npcm_rng_driver); |
| |
| MODULE_DESCRIPTION("Nuvoton NPCM Random Number Generator Driver"); |
| MODULE_AUTHOR("Tomer Maimon <tomer.maimon@nuvoton.com>"); |
| MODULE_LICENSE("GPL v2"); |