Commit ebc915ad authored by Michael Buesch's avatar Michael Buesch Committed by Linus Torvalds
Browse files

[PATCH] Add TI OMAP CPU family HW RNG driver


Signed-off-by: default avatarMichael Buesch <mb@bu3sch.de>
Cc: Jeff Garzik <jeff@garzik.org>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent d7174bcb
......@@ -74,3 +74,17 @@ config HW_RANDOM_IXP4XX
module will be called ixp4xx-rng.
If unsure, say Y.
config HW_RANDOM_OMAP
tristate "OMAP Random Number Generator support"
depends on HW_RANDOM && (ARCH_OMAP16XX || ARCH_OMAP24XX)
default y
---help---
This driver provides kernel-side support for the Random Number
Generator hardware found on OMAP16xx and OMAP24xx multimedia
processors.
To compile this driver as a module, choose M here: the
module will be called omap-rng.
If unsure, say Y.
......@@ -8,3 +8,4 @@ obj-$(CONFIG_HW_RANDOM_AMD) += amd-rng.o
obj-$(CONFIG_HW_RANDOM_GEODE) += geode-rng.o
obj-$(CONFIG_HW_RANDOM_VIA) += via-rng.o
obj-$(CONFIG_HW_RANDOM_IXP4XX) += ixp4xx-rng.o
obj-$(CONFIG_HW_RANDOM_OMAP) += omap-rng.o
/*
* driver/char/hw_random/omap-rng.c
*
* RNG driver for TI OMAP CPU family
*
* Author: Deepak Saxena <dsaxena@plexity.net>
*
* Copyright 2005 (c) MontaVista Software, Inc.
*
* Mostly based on original driver:
*
* Copyright (C) 2005 Nokia Corporation
* Author: Juha Yrj��<juha.yrjola@nokia.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.
*
* TODO:
*
* - Make status updated be interrupt driven so we don't poll
*
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/random.h>
#include <linux/err.h>
#include <linux/device.h>
#include <linux/hw_random.h>
#include <asm/io.h>
#include <asm/hardware/clock.h>
#define RNG_OUT_REG 0x00 /* Output register */
#define RNG_STAT_REG 0x04 /* Status register
[0] = STAT_BUSY */
#define RNG_ALARM_REG 0x24 /* Alarm register
[7:0] = ALARM_COUNTER */
#define RNG_CONFIG_REG 0x28 /* Configuration register
[11:6] = RESET_COUNT
[5:3] = RING2_DELAY
[2:0] = RING1_DELAY */
#define RNG_REV_REG 0x3c /* Revision register
[7:0] = REV_NB */
#define RNG_MASK_REG 0x40 /* Mask and reset register
[2] = IT_EN
[1] = SOFTRESET
[0] = AUTOIDLE */
#define RNG_SYSSTATUS 0x44 /* System status
[0] = RESETDONE */
static void __iomem *rng_base;
static struct clk *rng_ick;
static struct device *rng_dev;
static u32 omap_rng_read_reg(int reg)
{
return __raw_readl(rng_base + reg);
}
static void omap_rng_write_reg(int reg, u32 val)
{
__raw_writel(val, rng_base + reg);
}
/* REVISIT: Does the status bit really work on 16xx? */
static int omap_rng_data_present(struct hwrng *rng)
{
return omap_rng_read_reg(RNG_STAT_REG) ? 0 : 1;
}
static int omap_rng_data_read(struct hwrng *rng, u32 *data)
{
*data = omap_rng_read_reg(RNG_OUT_REG);
return 4;
}
static struct hwrng omap_rng_ops = {
.name = "omap",
.data_present = omap_rng_data_present,
.data_read = omap_rng_data_read,
};
static int __init omap_rng_probe(struct device *dev)
{
struct platform_device *pdev = to_platform_device(dev);
struct resource *res, *mem;
int ret;
/*
* A bit ugly, and it will never actually happen but there can
* be only one RNG and this catches any bork
*/
BUG_ON(rng_dev);
if (cpu_is_omap24xx()) {
rng_ick = clk_get(NULL, "rng_ick");
if (IS_ERR(rng_ick)) {
dev_err(dev, "Could not get rng_ick\n");
ret = PTR_ERR(rng_ick);
return ret;
}
else {
clk_use(rng_ick);
}
}
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!res)
return -ENOENT;
mem = request_mem_region(res->start, res->end - res->start + 1,
pdev->name);
if (mem == NULL)
return -EBUSY;
dev_set_drvdata(dev, mem);
rng_base = (u32 __iomem *)io_p2v(res->start);
ret = hwrng_register(&omap_rng_ops);
if (ret) {
release_resource(mem);
rng_base = NULL;
return ret;
}
dev_info(dev, "OMAP Random Number Generator ver. %02x\n",
omap_rng_read_reg(RNG_REV_REG));
omap_rng_write_reg(RNG_MASK_REG, 0x1);
rng_dev = dev;
return 0;
}
static int __exit omap_rng_remove(struct device *dev)
{
struct resource *mem = dev_get_drvdata(dev);
hwrng_unregister(&omap_rng_ops);
omap_rng_write_reg(RNG_MASK_REG, 0x0);
if (cpu_is_omap24xx()) {
clk_unuse(rng_ick);
clk_put(rng_ick);
}
release_resource(mem);
rng_base = NULL;
return 0;
}
#ifdef CONFIG_PM
static int omap_rng_suspend(struct device *dev, pm_message_t message, u32 level)
{
omap_rng_write_reg(RNG_MASK_REG, 0x0);
return 0;
}
static int omap_rng_resume(struct device *dev, pm_message_t message, u32 level)
{
omap_rng_write_reg(RNG_MASK_REG, 0x1);
return 1;
}
#else
#define omap_rng_suspend NULL
#define omap_rng_resume NULL
#endif
static struct device_driver omap_rng_driver = {
.name = "omap_rng",
.bus = &platform_bus_type,
.probe = omap_rng_probe,
.remove = __exit_p(omap_rng_remove),
.suspend = omap_rng_suspend,
.resume = omap_rng_resume
};
static int __init omap_rng_init(void)
{
if (!cpu_is_omap16xx() && !cpu_is_omap24xx())
return -ENODEV;
return driver_register(&omap_rng_driver);
}
static void __exit omap_rng_exit(void)
{
driver_unregister(&omap_rng_driver);
}
module_init(omap_rng_init);
module_exit(omap_rng_exit);
MODULE_AUTHOR("Deepak Saxena (and others)");
MODULE_LICENSE("GPL");
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