mirror of https://gitee.com/openkylin/linux.git
184 lines
4.7 KiB
C
184 lines
4.7 KiB
C
/*
|
|
* exynos-rng.c - Random Number Generator driver for the exynos
|
|
*
|
|
* Copyright (C) 2012 Samsung Electronics
|
|
* Jonghwa Lee <jonghwa3.lee@smasung.com>
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License as published by
|
|
* the Free Software Foundation;
|
|
*
|
|
* This program is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License
|
|
* along with this program; if not, write to the Free Software
|
|
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
|
|
*
|
|
*/
|
|
|
|
#include <linux/hw_random.h>
|
|
#include <linux/kernel.h>
|
|
#include <linux/module.h>
|
|
#include <linux/io.h>
|
|
#include <linux/platform_device.h>
|
|
#include <linux/clk.h>
|
|
#include <linux/pm_runtime.h>
|
|
#include <linux/err.h>
|
|
|
|
#define EXYNOS_PRNG_STATUS_OFFSET 0x10
|
|
#define EXYNOS_PRNG_SEED_OFFSET 0x140
|
|
#define EXYNOS_PRNG_OUT1_OFFSET 0x160
|
|
#define SEED_SETTING_DONE BIT(1)
|
|
#define PRNG_START 0x18
|
|
#define PRNG_DONE BIT(5)
|
|
#define EXYNOS_AUTOSUSPEND_DELAY 100
|
|
|
|
struct exynos_rng {
|
|
struct device *dev;
|
|
struct hwrng rng;
|
|
void __iomem *mem;
|
|
struct clk *clk;
|
|
};
|
|
|
|
static u32 exynos_rng_readl(struct exynos_rng *rng, u32 offset)
|
|
{
|
|
return __raw_readl(rng->mem + offset);
|
|
}
|
|
|
|
static void exynos_rng_writel(struct exynos_rng *rng, u32 val, u32 offset)
|
|
{
|
|
__raw_writel(val, rng->mem + offset);
|
|
}
|
|
|
|
static int exynos_init(struct hwrng *rng)
|
|
{
|
|
struct exynos_rng *exynos_rng = container_of(rng,
|
|
struct exynos_rng, rng);
|
|
int i;
|
|
int ret = 0;
|
|
|
|
pm_runtime_get_sync(exynos_rng->dev);
|
|
|
|
for (i = 0 ; i < 5 ; i++)
|
|
exynos_rng_writel(exynos_rng, jiffies,
|
|
EXYNOS_PRNG_SEED_OFFSET + 4*i);
|
|
|
|
if (!(exynos_rng_readl(exynos_rng, EXYNOS_PRNG_STATUS_OFFSET)
|
|
& SEED_SETTING_DONE))
|
|
ret = -EIO;
|
|
|
|
pm_runtime_put_noidle(exynos_rng->dev);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static int exynos_read(struct hwrng *rng, void *buf,
|
|
size_t max, bool wait)
|
|
{
|
|
struct exynos_rng *exynos_rng = container_of(rng,
|
|
struct exynos_rng, rng);
|
|
u32 *data = buf;
|
|
|
|
pm_runtime_get_sync(exynos_rng->dev);
|
|
|
|
exynos_rng_writel(exynos_rng, PRNG_START, 0);
|
|
|
|
while (!(exynos_rng_readl(exynos_rng,
|
|
EXYNOS_PRNG_STATUS_OFFSET) & PRNG_DONE))
|
|
cpu_relax();
|
|
|
|
exynos_rng_writel(exynos_rng, PRNG_DONE, EXYNOS_PRNG_STATUS_OFFSET);
|
|
|
|
*data = exynos_rng_readl(exynos_rng, EXYNOS_PRNG_OUT1_OFFSET);
|
|
|
|
pm_runtime_mark_last_busy(exynos_rng->dev);
|
|
pm_runtime_autosuspend(exynos_rng->dev);
|
|
|
|
return 4;
|
|
}
|
|
|
|
static int exynos_rng_probe(struct platform_device *pdev)
|
|
{
|
|
struct exynos_rng *exynos_rng;
|
|
struct resource *res;
|
|
|
|
exynos_rng = devm_kzalloc(&pdev->dev, sizeof(struct exynos_rng),
|
|
GFP_KERNEL);
|
|
if (!exynos_rng)
|
|
return -ENOMEM;
|
|
|
|
exynos_rng->dev = &pdev->dev;
|
|
exynos_rng->rng.name = "exynos";
|
|
exynos_rng->rng.init = exynos_init;
|
|
exynos_rng->rng.read = exynos_read;
|
|
exynos_rng->clk = devm_clk_get(&pdev->dev, "secss");
|
|
if (IS_ERR(exynos_rng->clk)) {
|
|
dev_err(&pdev->dev, "Couldn't get clock.\n");
|
|
return -ENOENT;
|
|
}
|
|
|
|
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
|
|
exynos_rng->mem = devm_ioremap_resource(&pdev->dev, res);
|
|
if (IS_ERR(exynos_rng->mem))
|
|
return PTR_ERR(exynos_rng->mem);
|
|
|
|
platform_set_drvdata(pdev, exynos_rng);
|
|
|
|
pm_runtime_set_autosuspend_delay(&pdev->dev, EXYNOS_AUTOSUSPEND_DELAY);
|
|
pm_runtime_use_autosuspend(&pdev->dev);
|
|
pm_runtime_enable(&pdev->dev);
|
|
|
|
return hwrng_register(&exynos_rng->rng);
|
|
}
|
|
|
|
static int exynos_rng_remove(struct platform_device *pdev)
|
|
{
|
|
struct exynos_rng *exynos_rng = platform_get_drvdata(pdev);
|
|
|
|
hwrng_unregister(&exynos_rng->rng);
|
|
|
|
return 0;
|
|
}
|
|
|
|
#ifdef CONFIG_PM
|
|
static int exynos_rng_runtime_suspend(struct device *dev)
|
|
{
|
|
struct platform_device *pdev = to_platform_device(dev);
|
|
struct exynos_rng *exynos_rng = platform_get_drvdata(pdev);
|
|
|
|
clk_disable_unprepare(exynos_rng->clk);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int exynos_rng_runtime_resume(struct device *dev)
|
|
{
|
|
struct platform_device *pdev = to_platform_device(dev);
|
|
struct exynos_rng *exynos_rng = platform_get_drvdata(pdev);
|
|
|
|
return clk_prepare_enable(exynos_rng->clk);
|
|
}
|
|
#endif
|
|
|
|
static UNIVERSAL_DEV_PM_OPS(exynos_rng_pm_ops, exynos_rng_runtime_suspend,
|
|
exynos_rng_runtime_resume, NULL);
|
|
|
|
static struct platform_driver exynos_rng_driver = {
|
|
.driver = {
|
|
.name = "exynos-rng",
|
|
.owner = THIS_MODULE,
|
|
.pm = &exynos_rng_pm_ops,
|
|
},
|
|
.probe = exynos_rng_probe,
|
|
.remove = exynos_rng_remove,
|
|
};
|
|
|
|
module_platform_driver(exynos_rng_driver);
|
|
|
|
MODULE_DESCRIPTION("EXYNOS 4 H/W Random Number Generator driver");
|
|
MODULE_AUTHOR("Jonghwa Lee <jonghwa3.lee@samsung.com>");
|
|
MODULE_LICENSE("GPL");
|