156 lines
3.8 KiB
C
156 lines
3.8 KiB
C
/*
|
|
* Copyright (C) 2006-2007 PA Semi, Inc
|
|
*
|
|
* Maintained by: Olof Johansson <olof@lixom.net>
|
|
*
|
|
* Driver for the PWRficient onchip rng
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License version 2 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/module.h>
|
|
#include <linux/kernel.h>
|
|
#include <linux/platform_device.h>
|
|
#include <linux/hw_random.h>
|
|
#include <linux/delay.h>
|
|
#include <linux/of_platform.h>
|
|
#include <asm/io.h>
|
|
|
|
#define SDCRNG_CTL_REG 0x00
|
|
#define SDCRNG_CTL_FVLD_M 0x0000f000
|
|
#define SDCRNG_CTL_FVLD_S 12
|
|
#define SDCRNG_CTL_KSZ 0x00000800
|
|
#define SDCRNG_CTL_RSRC_CRG 0x00000010
|
|
#define SDCRNG_CTL_RSRC_RRG 0x00000000
|
|
#define SDCRNG_CTL_CE 0x00000004
|
|
#define SDCRNG_CTL_RE 0x00000002
|
|
#define SDCRNG_CTL_DR 0x00000001
|
|
#define SDCRNG_CTL_SELECT_RRG_RNG (SDCRNG_CTL_RE | SDCRNG_CTL_RSRC_RRG)
|
|
#define SDCRNG_CTL_SELECT_CRG_RNG (SDCRNG_CTL_CE | SDCRNG_CTL_RSRC_CRG)
|
|
#define SDCRNG_VAL_REG 0x20
|
|
|
|
#define MODULE_NAME "pasemi_rng"
|
|
|
|
static int pasemi_rng_data_present(struct hwrng *rng, int wait)
|
|
{
|
|
void __iomem *rng_regs = (void __iomem *)rng->priv;
|
|
int data, i;
|
|
|
|
for (i = 0; i < 20; i++) {
|
|
data = (in_le32(rng_regs + SDCRNG_CTL_REG)
|
|
& SDCRNG_CTL_FVLD_M) ? 1 : 0;
|
|
if (data || !wait)
|
|
break;
|
|
udelay(10);
|
|
}
|
|
return data;
|
|
}
|
|
|
|
static int pasemi_rng_data_read(struct hwrng *rng, u32 *data)
|
|
{
|
|
void __iomem *rng_regs = (void __iomem *)rng->priv;
|
|
*data = in_le32(rng_regs + SDCRNG_VAL_REG);
|
|
return 4;
|
|
}
|
|
|
|
static int pasemi_rng_init(struct hwrng *rng)
|
|
{
|
|
void __iomem *rng_regs = (void __iomem *)rng->priv;
|
|
u32 ctl;
|
|
|
|
ctl = SDCRNG_CTL_DR | SDCRNG_CTL_SELECT_RRG_RNG | SDCRNG_CTL_KSZ;
|
|
out_le32(rng_regs + SDCRNG_CTL_REG, ctl);
|
|
out_le32(rng_regs + SDCRNG_CTL_REG, ctl & ~SDCRNG_CTL_DR);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void pasemi_rng_cleanup(struct hwrng *rng)
|
|
{
|
|
void __iomem *rng_regs = (void __iomem *)rng->priv;
|
|
u32 ctl;
|
|
|
|
ctl = SDCRNG_CTL_RE | SDCRNG_CTL_CE;
|
|
out_le32(rng_regs + SDCRNG_CTL_REG,
|
|
in_le32(rng_regs + SDCRNG_CTL_REG) & ~ctl);
|
|
}
|
|
|
|
static struct hwrng pasemi_rng = {
|
|
.name = MODULE_NAME,
|
|
.init = pasemi_rng_init,
|
|
.cleanup = pasemi_rng_cleanup,
|
|
.data_present = pasemi_rng_data_present,
|
|
.data_read = pasemi_rng_data_read,
|
|
};
|
|
|
|
static int rng_probe(struct platform_device *ofdev)
|
|
{
|
|
void __iomem *rng_regs;
|
|
struct device_node *rng_np = ofdev->dev.of_node;
|
|
struct resource res;
|
|
int err = 0;
|
|
|
|
err = of_address_to_resource(rng_np, 0, &res);
|
|
if (err)
|
|
return -ENODEV;
|
|
|
|
rng_regs = ioremap(res.start, 0x100);
|
|
|
|
if (!rng_regs)
|
|
return -ENOMEM;
|
|
|
|
pasemi_rng.priv = (unsigned long)rng_regs;
|
|
|
|
printk(KERN_INFO "Registering PA Semi RNG\n");
|
|
|
|
err = hwrng_register(&pasemi_rng);
|
|
|
|
if (err)
|
|
iounmap(rng_regs);
|
|
|
|
return err;
|
|
}
|
|
|
|
static int rng_remove(struct platform_device *dev)
|
|
{
|
|
void __iomem *rng_regs = (void __iomem *)pasemi_rng.priv;
|
|
|
|
hwrng_unregister(&pasemi_rng);
|
|
iounmap(rng_regs);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static struct of_device_id rng_match[] = {
|
|
{ .compatible = "1682m-rng", },
|
|
{ .compatible = "pasemi,pwrficient-rng", },
|
|
{ },
|
|
};
|
|
|
|
static struct platform_driver rng_driver = {
|
|
.driver = {
|
|
.name = "pasemi-rng",
|
|
.owner = THIS_MODULE,
|
|
.of_match_table = rng_match,
|
|
},
|
|
.probe = rng_probe,
|
|
.remove = rng_remove,
|
|
};
|
|
|
|
module_platform_driver(rng_driver);
|
|
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_AUTHOR("Egor Martovetsky <egor@pasemi.com>");
|
|
MODULE_DESCRIPTION("H/W RNG driver for PA Semi processor");
|