mirror of
https://github.com/torvalds/linux.git
synced 2024-12-22 02:52:56 +00:00
255 lines
6.6 KiB
C
255 lines
6.6 KiB
C
|
/*
|
||
|
* Copyright (C) 2015 Broadcom Corporation
|
||
|
*
|
||
|
* 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 version 2.
|
||
|
*
|
||
|
* This program is distributed "as is" WITHOUT ANY WARRANTY of any
|
||
|
* kind, whether express or implied; without even the implied warranty
|
||
|
* of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
||
|
* GNU General Public License for more details.
|
||
|
*/
|
||
|
/*
|
||
|
* DESCRIPTION: The Broadcom iProc RNG200 Driver
|
||
|
*/
|
||
|
|
||
|
#include <linux/hw_random.h>
|
||
|
#include <linux/init.h>
|
||
|
#include <linux/io.h>
|
||
|
#include <linux/kernel.h>
|
||
|
#include <linux/module.h>
|
||
|
#include <linux/of_address.h>
|
||
|
#include <linux/of_platform.h>
|
||
|
#include <linux/platform_device.h>
|
||
|
#include <linux/delay.h>
|
||
|
|
||
|
/* Registers */
|
||
|
#define RNG_CTRL_OFFSET 0x00
|
||
|
#define RNG_CTRL_RNG_RBGEN_MASK 0x00001FFF
|
||
|
#define RNG_CTRL_RNG_RBGEN_ENABLE 0x00000001
|
||
|
#define RNG_CTRL_RNG_RBGEN_DISABLE 0x00000000
|
||
|
|
||
|
#define RNG_SOFT_RESET_OFFSET 0x04
|
||
|
#define RNG_SOFT_RESET 0x00000001
|
||
|
|
||
|
#define RBG_SOFT_RESET_OFFSET 0x08
|
||
|
#define RBG_SOFT_RESET 0x00000001
|
||
|
|
||
|
#define RNG_INT_STATUS_OFFSET 0x18
|
||
|
#define RNG_INT_STATUS_MASTER_FAIL_LOCKOUT_IRQ_MASK 0x80000000
|
||
|
#define RNG_INT_STATUS_STARTUP_TRANSITIONS_MET_IRQ_MASK 0x00020000
|
||
|
#define RNG_INT_STATUS_NIST_FAIL_IRQ_MASK 0x00000020
|
||
|
#define RNG_INT_STATUS_TOTAL_BITS_COUNT_IRQ_MASK 0x00000001
|
||
|
|
||
|
#define RNG_FIFO_DATA_OFFSET 0x20
|
||
|
|
||
|
#define RNG_FIFO_COUNT_OFFSET 0x24
|
||
|
#define RNG_FIFO_COUNT_RNG_FIFO_COUNT_MASK 0x000000FF
|
||
|
|
||
|
struct iproc_rng200_dev {
|
||
|
void __iomem *base;
|
||
|
};
|
||
|
|
||
|
static void iproc_rng200_restart(void __iomem *rng_base)
|
||
|
{
|
||
|
uint32_t val;
|
||
|
|
||
|
/* Disable RBG */
|
||
|
val = ioread32(rng_base + RNG_CTRL_OFFSET);
|
||
|
val &= ~RNG_CTRL_RNG_RBGEN_MASK;
|
||
|
val |= RNG_CTRL_RNG_RBGEN_DISABLE;
|
||
|
iowrite32(val, rng_base + RNG_CTRL_OFFSET);
|
||
|
|
||
|
/* Clear all interrupt status */
|
||
|
iowrite32(0xFFFFFFFFUL, rng_base + RNG_INT_STATUS_OFFSET);
|
||
|
|
||
|
/* Reset RNG and RBG */
|
||
|
val = ioread32(rng_base + RBG_SOFT_RESET_OFFSET);
|
||
|
val |= RBG_SOFT_RESET;
|
||
|
iowrite32(val, rng_base + RBG_SOFT_RESET_OFFSET);
|
||
|
|
||
|
val = ioread32(rng_base + RNG_SOFT_RESET_OFFSET);
|
||
|
val |= RNG_SOFT_RESET;
|
||
|
iowrite32(val, rng_base + RNG_SOFT_RESET_OFFSET);
|
||
|
|
||
|
val = ioread32(rng_base + RNG_SOFT_RESET_OFFSET);
|
||
|
val &= ~RNG_SOFT_RESET;
|
||
|
iowrite32(val, rng_base + RNG_SOFT_RESET_OFFSET);
|
||
|
|
||
|
val = ioread32(rng_base + RBG_SOFT_RESET_OFFSET);
|
||
|
val &= ~RBG_SOFT_RESET;
|
||
|
iowrite32(val, rng_base + RBG_SOFT_RESET_OFFSET);
|
||
|
|
||
|
/* Enable RBG */
|
||
|
val = ioread32(rng_base + RNG_CTRL_OFFSET);
|
||
|
val &= ~RNG_CTRL_RNG_RBGEN_MASK;
|
||
|
val |= RNG_CTRL_RNG_RBGEN_ENABLE;
|
||
|
iowrite32(val, rng_base + RNG_CTRL_OFFSET);
|
||
|
}
|
||
|
|
||
|
static int iproc_rng200_read(struct hwrng *rng, void *buf, size_t max,
|
||
|
bool wait)
|
||
|
{
|
||
|
uint32_t status;
|
||
|
uint32_t num_remaining = max;
|
||
|
struct iproc_rng200_dev *priv = (struct iproc_rng200_dev *)rng->priv;
|
||
|
|
||
|
#define MAX_RESETS_PER_READ 1
|
||
|
uint32_t num_resets = 0;
|
||
|
|
||
|
#define MAX_IDLE_TIME (1 * HZ)
|
||
|
unsigned long idle_endtime = jiffies + MAX_IDLE_TIME;
|
||
|
|
||
|
while ((num_remaining > 0) && time_before(jiffies, idle_endtime)) {
|
||
|
|
||
|
/* Is RNG sane? If not, reset it. */
|
||
|
status = ioread32(priv->base + RNG_INT_STATUS_OFFSET);
|
||
|
if ((status & (RNG_INT_STATUS_MASTER_FAIL_LOCKOUT_IRQ_MASK |
|
||
|
RNG_INT_STATUS_NIST_FAIL_IRQ_MASK)) != 0) {
|
||
|
|
||
|
if (num_resets >= MAX_RESETS_PER_READ)
|
||
|
return max - num_remaining;
|
||
|
|
||
|
iproc_rng200_restart(priv->base);
|
||
|
num_resets++;
|
||
|
}
|
||
|
|
||
|
/* Are there any random numbers available? */
|
||
|
if ((ioread32(priv->base + RNG_FIFO_COUNT_OFFSET) &
|
||
|
RNG_FIFO_COUNT_RNG_FIFO_COUNT_MASK) > 0) {
|
||
|
|
||
|
if (num_remaining >= sizeof(uint32_t)) {
|
||
|
/* Buffer has room to store entire word */
|
||
|
*(uint32_t *)buf = ioread32(priv->base +
|
||
|
RNG_FIFO_DATA_OFFSET);
|
||
|
buf += sizeof(uint32_t);
|
||
|
num_remaining -= sizeof(uint32_t);
|
||
|
} else {
|
||
|
/* Buffer can only store partial word */
|
||
|
uint32_t rnd_number = ioread32(priv->base +
|
||
|
RNG_FIFO_DATA_OFFSET);
|
||
|
memcpy(buf, &rnd_number, num_remaining);
|
||
|
buf += num_remaining;
|
||
|
num_remaining = 0;
|
||
|
}
|
||
|
|
||
|
/* Reset the IDLE timeout */
|
||
|
idle_endtime = jiffies + MAX_IDLE_TIME;
|
||
|
} else {
|
||
|
if (!wait)
|
||
|
/* Cannot wait, return immediately */
|
||
|
return max - num_remaining;
|
||
|
|
||
|
/* Can wait, give others chance to run */
|
||
|
usleep_range(min(num_remaining * 10, 500U), 500);
|
||
|
}
|
||
|
}
|
||
|
|
||
|
return max - num_remaining;
|
||
|
}
|
||
|
|
||
|
static int iproc_rng200_init(struct hwrng *rng)
|
||
|
{
|
||
|
uint32_t val;
|
||
|
struct iproc_rng200_dev *priv;
|
||
|
|
||
|
priv = (struct iproc_rng200_dev *)rng->priv;
|
||
|
|
||
|
/* Setup RNG. */
|
||
|
val = ioread32(priv->base + RNG_CTRL_OFFSET);
|
||
|
val &= ~RNG_CTRL_RNG_RBGEN_MASK;
|
||
|
val |= RNG_CTRL_RNG_RBGEN_ENABLE;
|
||
|
iowrite32(val, priv->base + RNG_CTRL_OFFSET);
|
||
|
|
||
|
return 0;
|
||
|
}
|
||
|
|
||
|
static void iproc_rng200_cleanup(struct hwrng *rng)
|
||
|
{
|
||
|
uint32_t val;
|
||
|
struct iproc_rng200_dev *priv;
|
||
|
|
||
|
priv = (struct iproc_rng200_dev *)rng->priv;
|
||
|
|
||
|
/* Disable RNG hardware */
|
||
|
val = ioread32(priv->base + RNG_CTRL_OFFSET);
|
||
|
val &= ~RNG_CTRL_RNG_RBGEN_MASK;
|
||
|
val |= RNG_CTRL_RNG_RBGEN_DISABLE;
|
||
|
iowrite32(val, priv->base + RNG_CTRL_OFFSET);
|
||
|
}
|
||
|
|
||
|
static struct hwrng iproc_rng200_ops = {
|
||
|
.name = "iproc-rng200",
|
||
|
.read = iproc_rng200_read,
|
||
|
.init = iproc_rng200_init,
|
||
|
.cleanup = iproc_rng200_cleanup,
|
||
|
};
|
||
|
|
||
|
static int iproc_rng200_probe(struct platform_device *pdev)
|
||
|
{
|
||
|
struct iproc_rng200_dev *priv;
|
||
|
struct resource *res;
|
||
|
struct device *dev = &pdev->dev;
|
||
|
int ret;
|
||
|
|
||
|
priv = devm_kzalloc(dev, sizeof(struct iproc_rng200_dev), GFP_KERNEL);
|
||
|
if (!priv)
|
||
|
return -ENOMEM;
|
||
|
|
||
|
iproc_rng200_ops.priv = (unsigned long)priv;
|
||
|
platform_set_drvdata(pdev, priv);
|
||
|
|
||
|
/* Map peripheral */
|
||
|
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
|
||
|
if (!res) {
|
||
|
dev_err(dev, "failed to get rng resources\n");
|
||
|
return -EINVAL;
|
||
|
}
|
||
|
|
||
|
priv->base = devm_ioremap_resource(dev, res);
|
||
|
if (IS_ERR(priv->base)) {
|
||
|
dev_err(dev, "failed to remap rng regs\n");
|
||
|
return PTR_ERR(priv->base);
|
||
|
}
|
||
|
|
||
|
/* Register driver */
|
||
|
ret = hwrng_register(&iproc_rng200_ops);
|
||
|
if (ret) {
|
||
|
dev_err(dev, "hwrng registration failed\n");
|
||
|
return ret;
|
||
|
}
|
||
|
|
||
|
dev_info(dev, "hwrng registered\n");
|
||
|
|
||
|
return 0;
|
||
|
}
|
||
|
|
||
|
static int iproc_rng200_remove(struct platform_device *pdev)
|
||
|
{
|
||
|
/* Unregister driver */
|
||
|
hwrng_unregister(&iproc_rng200_ops);
|
||
|
|
||
|
return 0;
|
||
|
}
|
||
|
|
||
|
static const struct of_device_id iproc_rng200_of_match[] = {
|
||
|
{ .compatible = "brcm,iproc-rng200", },
|
||
|
{},
|
||
|
};
|
||
|
MODULE_DEVICE_TABLE(of, iproc_rng200_of_match);
|
||
|
|
||
|
static struct platform_driver iproc_rng200_driver = {
|
||
|
.driver = {
|
||
|
.name = "iproc-rng200",
|
||
|
.of_match_table = iproc_rng200_of_match,
|
||
|
},
|
||
|
.probe = iproc_rng200_probe,
|
||
|
.remove = iproc_rng200_remove,
|
||
|
};
|
||
|
module_platform_driver(iproc_rng200_driver);
|
||
|
|
||
|
MODULE_AUTHOR("Broadcom");
|
||
|
MODULE_DESCRIPTION("iProc RNG200 Random Number Generator driver");
|
||
|
MODULE_LICENSE("GPL v2");
|