diff options
| -rw-r--r-- | drivers/char/hw_random/Kconfig | 14 | ||||
| -rw-r--r-- | drivers/char/hw_random/Makefile | 1 | ||||
| -rw-r--r-- | drivers/char/hw_random/timeriomem-rng.c | 151 | ||||
| -rw-r--r-- | include/linux/timeriomem-rng.h | 21 |
4 files changed, 187 insertions, 0 deletions
diff --git a/drivers/char/hw_random/Kconfig b/drivers/char/hw_random/Kconfig index 8822eca..e86dd42 100644 --- a/drivers/char/hw_random/Kconfig +++ b/drivers/char/hw_random/Kconfig @@ -20,6 +20,20 @@ config HW_RANDOM If unsure, say Y. +config HW_RANDOM_TIMERIOMEM + tristate "Timer IOMEM HW Random Number Generator support" + depends on HW_RANDOM + ---help--- + This driver provides kernel-side support for a generic Random + Number Generator used by reading a 'dumb' iomem address that + is to be read no faster than, for example, once a second; + the default FPGA bitstream on the TS-7800 has such functionality. + + To compile this driver as a module, choose M here: the + module will be called timeriomem-rng. + + If unsure, say Y. + config HW_RANDOM_INTEL tristate "Intel HW Random Number Generator support" depends on HW_RANDOM && (X86 || IA64) && PCI diff --git a/drivers/char/hw_random/Makefile b/drivers/char/hw_random/Makefile index b6effb7..e81d21a 100644 --- a/drivers/char/hw_random/Makefile +++ b/drivers/char/hw_random/Makefile @@ -4,6 +4,7 @@ obj-$(CONFIG_HW_RANDOM) += rng-core.o rng-core-y := core.o +obj-$(CONFIG_HW_RANDOM_TIMERIOMEM) += timeriomem-rng.o obj-$(CONFIG_HW_RANDOM_INTEL) += intel-rng.o obj-$(CONFIG_HW_RANDOM_AMD) += amd-rng.o obj-$(CONFIG_HW_RANDOM_GEODE) += geode-rng.o diff --git a/drivers/char/hw_random/timeriomem-rng.c b/drivers/char/hw_random/timeriomem-rng.c new file mode 100644 index 0000000..10ad41b --- /dev/null +++ b/drivers/char/hw_random/timeriomem-rng.c @@ -0,0 +1,151 @@ +/* + * drivers/char/hw_random/timeriomem-rng.c + * + * Copyright (C) 2009 Alexander Clouter <alex@digriz.org.uk> + * + * Derived from drivers/char/hw_random/omap-rng.c + * Copyright 2005 (c) MontaVista Software, Inc. + * Author: Deepak Saxena <dsaxena@plexity.net> + * + * 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. + * + * Overview: + * This driver is useful for platforms that have an IO range that provides + * periodic random data from a single IO memory address. All the platform + * has to do is provide the address and 'wait time' that new data becomes + * available. + * + * TODO: add support for reading sizes other than 32bits and masking + */ + +#include <linux/module.h> +#include <linux/kernel.h> +#include <linux/platform_device.h> +#include <linux/hw_random.h> +#include <linux/io.h> +#include <linux/timeriomem-rng.h> +#include <linux/jiffies.h> +#include <linux/sched.h> +#include <linux/timer.h> +#include <linux/completion.h> + +static struct timeriomem_rng_data *timeriomem_rng_data; + +static void timeriomem_rng_trigger(unsigned long); +static DEFINE_TIMER(timeriomem_rng_timer, timeriomem_rng_trigger, 0, 0); + +/* + * have data return 1, however return 0 if we have nothing + */ +static int timeriomem_rng_data_present(struct hwrng *rng, int wait) +{ + if (rng->priv == 0) + return 1; + + if (!wait || timeriomem_rng_data->present) + return timeriomem_rng_data->present; + + wait_for_completion(&timeriomem_rng_data->completion); + + return 1; +} + +static int timeriomem_rng_data_read(struct hwrng *rng, u32 *data) +{ + unsigned long cur; + s32 delay; + + *data = readl(timeriomem_rng_data->address); + + if (rng->priv != 0) { + cur = jiffies; + + delay = cur - timeriomem_rng_timer.expires; + delay = rng->priv - (delay % rng->priv); + + timeriomem_rng_timer.expires = cur + delay; + timeriomem_rng_data->present = 0; + + init_completion(&timeriomem_rng_data->completion); + add_timer(&timeriomem_rng_timer); + } + + return 4; +} + +static void timeriomem_rng_trigger(unsigned long dummy) +{ + timeriomem_rng_data->present = 1; + complete(&timeriomem_rng_data->completion); +} + +static struct hwrng timeriomem_rng_ops = { + .name = "timeriomem", + .data_present = timeriomem_rng_data_present, + .data_read = timeriomem_rng_data_read, + .priv = 0, +}; + +static int __init timeriomem_rng_probe(struct platform_device *pdev) +{ + int ret; + + timeriomem_rng_data = pdev->dev.platform_data; + + if (timeriomem_rng_data->period != 0 + && usecs_to_jiffies(timeriomem_rng_data->period) > 0) { + timeriomem_rng_timer.expires = jiffies; + + timeriomem_rng_ops.priv = usecs_to_jiffies( + timeriomem_rng_data->period); + } + timeriomem_rng_data->present = 1; + + ret = hwrng_register(&timeriomem_rng_ops); + if (ret) { + dev_err(&pdev->dev, "problem registering\n"); + return ret; + } + + dev_info(&pdev->dev, "32bits from 0x%p @ %dus\n", + timeriomem_rng_data->address, + timeriomem_rng_data->period); + + return 0; +} + +static int __devexit timeriomem_rng_remove(struct platform_device *pdev) +{ + del_timer_sync(&timeriomem_rng_timer); + hwrng_unregister(&timeriomem_rng_ops); + + return 0; +} + +static struct platform_driver timeriomem_rng_driver = { + .driver = { + .name = "timeriomem_rng", + .owner = THIS_MODULE, + }, + .probe = timeriomem_rng_probe, + .remove = __devexit_p(timeriomem_rng_remove), +}; + +static int __init timeriomem_rng_init(void) +{ + return platform_driver_register(&timeriomem_rng_driver); +} + +static void __exit timeriomem_rng_exit(void) +{ + platform_driver_unregister(&timeriomem_rng_driver); +} + +module_init(timeriomem_rng_init); +module_exit(timeriomem_rng_exit); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Alexander Clouter <alex@digriz.org.uk>"); +MODULE_DESCRIPTION("Timer IOMEM H/W RNG driver"); diff --git a/include/linux/timeriomem-rng.h b/include/linux/timeriomem-rng.h new file mode 100644 index 0000000..dd25317 --- /dev/null +++ b/include/linux/timeriomem-rng.h @@ -0,0 +1,21 @@ +/* + * linux/include/linux/timeriomem-rng.h + * + * Copyright (c) 2009 Alexander Clouter <alex@digriz.org.uk> + * + * 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. + */ + +#include <linux/completion.h> + +struct timeriomem_rng_data { + struct completion completion; + unsigned int present:1; + + u32 __iomem *address; + + /* measures in usecs */ + unsigned int period; +}; |
