linux/drivers/char/hw_random/omap3-rom-rng.c
Jingoo Han 0574bce969 hwrng: omap3-rom - Use devm_clk_get()
Use devm_clk_get() to make cleanup paths simpler.

Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2014-03-10 20:13:36 +08:00

141 lines
3.1 KiB
C

/*
* omap3-rom-rng.c - RNG driver for TI OMAP3 CPU family
*
* Copyright (C) 2009 Nokia Corporation
* Author: Juha Yrjola <juha.yrjola@solidboot.com>
*
* Copyright (C) 2013 Pali Rohár <pali.rohar@gmail.com>
*
* This file is licensed under the terms of the GNU General Public
* License version 2. This program is licensed "as is" without any
* warranty of any kind, whether express or implied.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/module.h>
#include <linux/init.h>
#include <linux/random.h>
#include <linux/hw_random.h>
#include <linux/timer.h>
#include <linux/clk.h>
#include <linux/err.h>
#include <linux/platform_device.h>
#define RNG_RESET 0x01
#define RNG_GEN_PRNG_HW_INIT 0x02
#define RNG_GEN_HW 0x08
/* param1: ptr, param2: count, param3: flag */
static u32 (*omap3_rom_rng_call)(u32, u32, u32);
static struct timer_list idle_timer;
static int rng_idle;
static struct clk *rng_clk;
static void omap3_rom_rng_idle(unsigned long data)
{
int r;
r = omap3_rom_rng_call(0, 0, RNG_RESET);
if (r != 0) {
pr_err("reset failed: %d\n", r);
return;
}
clk_disable_unprepare(rng_clk);
rng_idle = 1;
}
static int omap3_rom_rng_get_random(void *buf, unsigned int count)
{
u32 r;
u32 ptr;
del_timer_sync(&idle_timer);
if (rng_idle) {
clk_prepare_enable(rng_clk);
r = omap3_rom_rng_call(0, 0, RNG_GEN_PRNG_HW_INIT);
if (r != 0) {
clk_disable_unprepare(rng_clk);
pr_err("HW init failed: %d\n", r);
return -EIO;
}
rng_idle = 0;
}
ptr = virt_to_phys(buf);
r = omap3_rom_rng_call(ptr, count, RNG_GEN_HW);
mod_timer(&idle_timer, jiffies + msecs_to_jiffies(500));
if (r != 0)
return -EINVAL;
return 0;
}
static int omap3_rom_rng_data_present(struct hwrng *rng, int wait)
{
return 1;
}
static int omap3_rom_rng_data_read(struct hwrng *rng, u32 *data)
{
int r;
r = omap3_rom_rng_get_random(data, 4);
if (r < 0)
return r;
return 4;
}
static struct hwrng omap3_rom_rng_ops = {
.name = "omap3-rom",
.data_present = omap3_rom_rng_data_present,
.data_read = omap3_rom_rng_data_read,
};
static int omap3_rom_rng_probe(struct platform_device *pdev)
{
pr_info("initializing\n");
omap3_rom_rng_call = pdev->dev.platform_data;
if (!omap3_rom_rng_call) {
pr_err("omap3_rom_rng_call is NULL\n");
return -EINVAL;
}
setup_timer(&idle_timer, omap3_rom_rng_idle, 0);
rng_clk = devm_clk_get(&pdev->dev, "ick");
if (IS_ERR(rng_clk)) {
pr_err("unable to get RNG clock\n");
return PTR_ERR(rng_clk);
}
/* Leave the RNG in reset state. */
clk_prepare_enable(rng_clk);
omap3_rom_rng_idle(0);
return hwrng_register(&omap3_rom_rng_ops);
}
static int omap3_rom_rng_remove(struct platform_device *pdev)
{
hwrng_unregister(&omap3_rom_rng_ops);
clk_disable_unprepare(rng_clk);
return 0;
}
static struct platform_driver omap3_rom_rng_driver = {
.driver = {
.name = "omap3-rom-rng",
.owner = THIS_MODULE,
},
.probe = omap3_rom_rng_probe,
.remove = omap3_rom_rng_remove,
};
module_platform_driver(omap3_rom_rng_driver);
MODULE_ALIAS("platform:omap3-rom-rng");
MODULE_AUTHOR("Juha Yrjola");
MODULE_AUTHOR("Pali Rohár <pali.rohar@gmail.com>");
MODULE_LICENSE("GPL");