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![Herbert Xu](/assets/img/avatar_default.png)
This patch fixes an unused variable warning when this driver is built-in with CONFIG_OF=n. Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
184 lines
4.4 KiB
C
184 lines
4.4 KiB
C
// 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 >= sizeof(u32)) {
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if (wait) {
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if (readl_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 ((readl(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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*(u32 *)buf = readl(priv->base + NPCM_RNGD_REG);
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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 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 <tomer.maimon@nuvoton.com>");
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MODULE_LICENSE("GPL v2");
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