153 lines
3.4 KiB
C
153 lines
3.4 KiB
C
// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
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/*
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* Copyright (c) 2016 BayLibre, SAS.
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* Author: Neil Armstrong <narmstrong@baylibre.com>
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* Copyright (C) 2014 Amlogic, Inc.
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*/
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#include <linux/err.h>
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#include <linux/module.h>
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#include <linux/io.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/slab.h>
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#include <linux/types.h>
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#include <linux/of.h>
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#include <linux/clk.h>
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#include <linux/iopoll.h>
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#define RNG_DATA 0x00
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#define RNG_S4_DATA 0x08
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#define RNG_S4_CFG 0x00
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#define RUN_BIT BIT(0)
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#define SEED_READY_STS_BIT BIT(31)
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struct meson_rng_priv {
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int (*read)(struct hwrng *rng, void *buf, size_t max, bool wait);
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};
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struct meson_rng_data {
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void __iomem *base;
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struct hwrng rng;
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struct device *dev;
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};
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static int meson_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait)
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{
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struct meson_rng_data *data =
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container_of(rng, struct meson_rng_data, rng);
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*(u32 *)buf = readl_relaxed(data->base + RNG_DATA);
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return sizeof(u32);
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}
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static int meson_rng_wait_status(void __iomem *cfg_addr, int bit)
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{
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u32 status = 0;
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int ret;
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ret = readl_relaxed_poll_timeout_atomic(cfg_addr,
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status, !(status & bit),
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10, 10000);
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if (ret)
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return -EBUSY;
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return 0;
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}
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static int meson_s4_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait)
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{
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struct meson_rng_data *data =
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container_of(rng, struct meson_rng_data, rng);
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void __iomem *cfg_addr = data->base + RNG_S4_CFG;
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int err;
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writel_relaxed(readl_relaxed(cfg_addr) | SEED_READY_STS_BIT, cfg_addr);
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err = meson_rng_wait_status(cfg_addr, SEED_READY_STS_BIT);
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if (err) {
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dev_err(data->dev, "Seed isn't ready, try again\n");
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return err;
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}
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err = meson_rng_wait_status(cfg_addr, RUN_BIT);
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if (err) {
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dev_err(data->dev, "Can't get random number, try again\n");
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return err;
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}
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*(u32 *)buf = readl_relaxed(data->base + RNG_S4_DATA);
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return sizeof(u32);
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}
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static int meson_rng_probe(struct platform_device *pdev)
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{
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struct device *dev = &pdev->dev;
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struct meson_rng_data *data;
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struct clk *core_clk;
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const struct meson_rng_priv *priv;
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data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
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if (!data)
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return -ENOMEM;
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priv = device_get_match_data(&pdev->dev);
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if (!priv)
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return -ENODEV;
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data->base = devm_platform_ioremap_resource(pdev, 0);
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if (IS_ERR(data->base))
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return PTR_ERR(data->base);
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core_clk = devm_clk_get_optional_enabled(dev, "core");
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if (IS_ERR(core_clk))
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return dev_err_probe(dev, PTR_ERR(core_clk),
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"Failed to get core clock\n");
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data->rng.name = pdev->name;
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data->rng.read = priv->read;
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data->dev = &pdev->dev;
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return devm_hwrng_register(dev, &data->rng);
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}
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static const struct meson_rng_priv meson_rng_priv = {
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.read = meson_rng_read,
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};
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static const struct meson_rng_priv meson_rng_priv_s4 = {
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.read = meson_s4_rng_read,
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};
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static const struct of_device_id meson_rng_of_match[] = {
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{
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.compatible = "amlogic,meson-rng",
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.data = (void *)&meson_rng_priv,
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},
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{
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.compatible = "amlogic,meson-s4-rng",
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.data = (void *)&meson_rng_priv_s4,
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},
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{},
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};
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MODULE_DEVICE_TABLE(of, meson_rng_of_match);
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static struct platform_driver meson_rng_driver = {
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.probe = meson_rng_probe,
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.driver = {
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.name = "meson-rng",
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.of_match_table = meson_rng_of_match,
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},
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};
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module_platform_driver(meson_rng_driver);
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MODULE_DESCRIPTION("Meson H/W Random Number Generator driver");
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MODULE_AUTHOR("Lawrence Mok <lawrence.mok@amlogic.com>");
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MODULE_AUTHOR("Neil Armstrong <narmstrong@baylibre.com>");
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MODULE_LICENSE("Dual BSD/GPL");
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