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![Ben Dooks](/assets/img/avatar_default.png)
The __raw IO functions are not endian safe, so use the readl_relaxed and writel_relaxed versions of these. Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
231 lines
5.7 KiB
C
231 lines
5.7 KiB
C
/*
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* exynos-rng.c - Random Number Generator driver for the exynos
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*
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* Copyright (C) 2012 Samsung Electronics
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* Jonghwa Lee <jonghwa3.lee@samsung.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation;
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*
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*/
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#include <linux/hw_random.h>
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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/platform_device.h>
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#include <linux/clk.h>
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#include <linux/pm_runtime.h>
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#include <linux/err.h>
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#define EXYNOS_PRNG_STATUS_OFFSET 0x10
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#define EXYNOS_PRNG_SEED_OFFSET 0x140
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#define EXYNOS_PRNG_OUT1_OFFSET 0x160
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#define SEED_SETTING_DONE BIT(1)
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#define PRNG_START 0x18
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#define PRNG_DONE BIT(5)
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#define EXYNOS_AUTOSUSPEND_DELAY 100
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struct exynos_rng {
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struct device *dev;
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struct hwrng rng;
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void __iomem *mem;
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struct clk *clk;
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};
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static u32 exynos_rng_readl(struct exynos_rng *rng, u32 offset)
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{
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return readl_relaxed(rng->mem + offset);
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}
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static void exynos_rng_writel(struct exynos_rng *rng, u32 val, u32 offset)
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{
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writel_relaxed(val, rng->mem + offset);
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}
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static int exynos_rng_configure(struct exynos_rng *exynos_rng)
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{
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int i;
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int ret = 0;
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for (i = 0 ; i < 5 ; i++)
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exynos_rng_writel(exynos_rng, jiffies,
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EXYNOS_PRNG_SEED_OFFSET + 4*i);
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if (!(exynos_rng_readl(exynos_rng, EXYNOS_PRNG_STATUS_OFFSET)
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& SEED_SETTING_DONE))
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ret = -EIO;
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return ret;
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}
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static int exynos_init(struct hwrng *rng)
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{
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struct exynos_rng *exynos_rng = container_of(rng,
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struct exynos_rng, rng);
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int ret = 0;
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pm_runtime_get_sync(exynos_rng->dev);
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ret = exynos_rng_configure(exynos_rng);
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pm_runtime_mark_last_busy(exynos_rng->dev);
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pm_runtime_put_autosuspend(exynos_rng->dev);
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return ret;
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}
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static int exynos_read(struct hwrng *rng, void *buf,
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size_t max, bool wait)
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{
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struct exynos_rng *exynos_rng = container_of(rng,
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struct exynos_rng, rng);
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u32 *data = buf;
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int retry = 100;
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int ret = 4;
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pm_runtime_get_sync(exynos_rng->dev);
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exynos_rng_writel(exynos_rng, PRNG_START, 0);
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while (!(exynos_rng_readl(exynos_rng,
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EXYNOS_PRNG_STATUS_OFFSET) & PRNG_DONE) && --retry)
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cpu_relax();
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if (!retry) {
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ret = -ETIMEDOUT;
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goto out;
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}
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exynos_rng_writel(exynos_rng, PRNG_DONE, EXYNOS_PRNG_STATUS_OFFSET);
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*data = exynos_rng_readl(exynos_rng, EXYNOS_PRNG_OUT1_OFFSET);
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out:
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pm_runtime_mark_last_busy(exynos_rng->dev);
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pm_runtime_put_sync_autosuspend(exynos_rng->dev);
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return ret;
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}
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static int exynos_rng_probe(struct platform_device *pdev)
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{
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struct exynos_rng *exynos_rng;
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struct resource *res;
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int ret;
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exynos_rng = devm_kzalloc(&pdev->dev, sizeof(struct exynos_rng),
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GFP_KERNEL);
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if (!exynos_rng)
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return -ENOMEM;
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exynos_rng->dev = &pdev->dev;
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exynos_rng->rng.name = "exynos";
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exynos_rng->rng.init = exynos_init;
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exynos_rng->rng.read = exynos_read;
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exynos_rng->clk = devm_clk_get(&pdev->dev, "secss");
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if (IS_ERR(exynos_rng->clk)) {
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dev_err(&pdev->dev, "Couldn't get clock.\n");
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return -ENOENT;
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}
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res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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exynos_rng->mem = devm_ioremap_resource(&pdev->dev, res);
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if (IS_ERR(exynos_rng->mem))
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return PTR_ERR(exynos_rng->mem);
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platform_set_drvdata(pdev, exynos_rng);
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pm_runtime_set_autosuspend_delay(&pdev->dev, EXYNOS_AUTOSUSPEND_DELAY);
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pm_runtime_use_autosuspend(&pdev->dev);
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pm_runtime_enable(&pdev->dev);
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ret = devm_hwrng_register(&pdev->dev, &exynos_rng->rng);
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if (ret) {
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pm_runtime_dont_use_autosuspend(&pdev->dev);
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pm_runtime_disable(&pdev->dev);
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}
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return ret;
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}
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static int exynos_rng_remove(struct platform_device *pdev)
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{
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pm_runtime_dont_use_autosuspend(&pdev->dev);
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pm_runtime_disable(&pdev->dev);
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return 0;
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}
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static int __maybe_unused exynos_rng_runtime_suspend(struct device *dev)
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{
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struct platform_device *pdev = to_platform_device(dev);
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struct exynos_rng *exynos_rng = platform_get_drvdata(pdev);
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clk_disable_unprepare(exynos_rng->clk);
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return 0;
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}
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static int __maybe_unused exynos_rng_runtime_resume(struct device *dev)
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{
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struct platform_device *pdev = to_platform_device(dev);
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struct exynos_rng *exynos_rng = platform_get_drvdata(pdev);
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return clk_prepare_enable(exynos_rng->clk);
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}
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static int __maybe_unused exynos_rng_suspend(struct device *dev)
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{
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return pm_runtime_force_suspend(dev);
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}
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static int __maybe_unused exynos_rng_resume(struct device *dev)
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{
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struct platform_device *pdev = to_platform_device(dev);
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struct exynos_rng *exynos_rng = platform_get_drvdata(pdev);
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int ret;
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ret = pm_runtime_force_resume(dev);
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if (ret)
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return ret;
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return exynos_rng_configure(exynos_rng);
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}
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static const struct dev_pm_ops exynos_rng_pm_ops = {
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SET_SYSTEM_SLEEP_PM_OPS(exynos_rng_suspend, exynos_rng_resume)
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SET_RUNTIME_PM_OPS(exynos_rng_runtime_suspend,
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exynos_rng_runtime_resume, NULL)
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};
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static const struct of_device_id exynos_rng_dt_match[] = {
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{
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.compatible = "samsung,exynos4-rng",
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},
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{ },
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};
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MODULE_DEVICE_TABLE(of, exynos_rng_dt_match);
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static struct platform_driver exynos_rng_driver = {
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.driver = {
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.name = "exynos-rng",
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.pm = &exynos_rng_pm_ops,
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.of_match_table = exynos_rng_dt_match,
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},
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.probe = exynos_rng_probe,
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.remove = exynos_rng_remove,
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};
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module_platform_driver(exynos_rng_driver);
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MODULE_DESCRIPTION("EXYNOS 4 H/W Random Number Generator driver");
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MODULE_AUTHOR("Jonghwa Lee <jonghwa3.lee@samsung.com>");
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MODULE_LICENSE("GPL");
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