diff options
| -rw-r--r-- | drivers/Kconfig | 1 | ||||
| -rw-r--r-- | drivers/Makefile | 1 | ||||
| -rw-r--r-- | drivers/hw_random/Kconfig | 6 | ||||
| -rw-r--r-- | drivers/hw_random/Makefile | 1 | ||||
| -rw-r--r-- | drivers/hw_random/core.c | 125 | ||||
| -rw-r--r-- | include/linux/hw_random.h | 47 |
6 files changed, 181 insertions, 0 deletions
diff --git a/drivers/Kconfig b/drivers/Kconfig index bf31115fa0..44159f83d3 100644 --- a/drivers/Kconfig +++ b/drivers/Kconfig @@ -22,6 +22,7 @@ source "drivers/eeprom/Kconfig" source "drivers/input/Kconfig" source "drivers/watchdog/Kconfig" source "drivers/pwm/Kconfig" +source "drivers/hw_random/Kconfig" source "drivers/dma/Kconfig" source "drivers/gpio/Kconfig" source "drivers/w1/Kconfig" diff --git a/drivers/Makefile b/drivers/Makefile index 0fadf4e44b..d46cc28869 100644 --- a/drivers/Makefile +++ b/drivers/Makefile @@ -22,6 +22,7 @@ obj-y += misc/ obj-y += dma/ obj-y += watchdog/ obj-y += gpio/ +obj-$(CONFIG_HWRNG) += hw_random/ obj-$(CONFIG_OFTREE) += of/ obj-$(CONFIG_W1) += w1/ obj-y += pinctrl/ diff --git a/drivers/hw_random/Kconfig b/drivers/hw_random/Kconfig new file mode 100644 index 0000000000..807fcadd31 --- /dev/null +++ b/drivers/hw_random/Kconfig @@ -0,0 +1,6 @@ +menuconfig HWRNG + bool "HWRNG Support" + help + Support for HWRNG(Hardware Random Number Generator) devices. + + If unsure, say no. diff --git a/drivers/hw_random/Makefile b/drivers/hw_random/Makefile new file mode 100644 index 0000000000..15307b100f --- /dev/null +++ b/drivers/hw_random/Makefile @@ -0,0 +1 @@ +obj-$(CONFIG_HWRNG) += core.o diff --git a/drivers/hw_random/core.c b/drivers/hw_random/core.c new file mode 100644 index 0000000000..ef2a988c76 --- /dev/null +++ b/drivers/hw_random/core.c @@ -0,0 +1,125 @@ +/* + * Copyright (c) 2016 Pengutronix, Steffen Trumtrar <kernel@pengutronix.de> + * + * 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. + * + * derived from Linux kernel drivers/char/hw_random/core.c + */ + +#include <common.h> +#include <linux/hw_random.h> +#include <malloc.h> + +static LIST_HEAD(hwrngs); + +#define RNG_BUFFER_SIZE 32 + +int hwrng_get_data(struct hwrng *rng, void *buffer, size_t size, int wait) +{ + return rng->read(rng, buffer, size, wait); +} + +static int hwrng_init(struct hwrng *rng) +{ + int ret = 0; + + if (rng->init) + ret = rng->init(rng); + + if (!ret) + list_add_tail(&rng->list, &hwrngs); + + return ret; +} + +static ssize_t rng_dev_read(struct cdev *cdev, void *buf, size_t size, + loff_t offset, unsigned long flags) +{ + struct hwrng *rng = container_of(cdev, struct hwrng, cdev); + size_t count = size; + ssize_t cur = 0; + int len; + + memset(buf, 0, size); + + while (count) { + int max = min(count, (size_t)RNG_BUFFER_SIZE); + len = hwrng_get_data(rng, rng->buf, max, true); + if (len < 0) { + cur = len; + break; + } + + memcpy(buf + cur, rng->buf, len); + + count -= len; + cur += len; + } + + return cur; +} + +static struct file_operations rng_chrdev_ops = { + .read = rng_dev_read, + .lseek = dev_lseek_default, +}; + +static int hwrng_register_cdev(struct hwrng *rng) +{ + struct device_d *dev = rng->dev; + const char *alias; + char *devname; + int err; + + alias = of_alias_get(dev->device_node); + if (alias) { + devname = xstrdup(alias); + } else { + err = cdev_find_free_index("hwrng"); + if (err < 0) { + dev_err(dev, "no index found to name device\n"); + return err; + } + devname = xasprintf("hwrng%d", err); + } + + rng->cdev.name = devname; + rng->cdev.flags = DEVFS_IS_CHARACTER_DEV; + rng->cdev.ops = &rng_chrdev_ops; + rng->cdev.dev = rng->dev; + + return devfs_create(&rng->cdev); +} + +struct hwrng *hwrng_get_first(void) +{ + if (list_empty(&hwrngs)) + return ERR_PTR(-ENODEV); + else + return list_first_entry(&hwrngs, struct hwrng, list); +} + +int hwrng_register(struct device_d *dev, struct hwrng *rng) +{ + int err; + + if (rng->name == NULL || rng->read == NULL) + return -EINVAL; + + rng->buf = xzalloc(RNG_BUFFER_SIZE); + rng->dev = dev; + + err = hwrng_init(rng); + if (err) { + free(rng->buf); + return err; + } + + err = hwrng_register_cdev(rng); + if (err) + free(rng->buf); + + return err; +} diff --git a/include/linux/hw_random.h b/include/linux/hw_random.h new file mode 100644 index 0000000000..bae442166c --- /dev/null +++ b/include/linux/hw_random.h @@ -0,0 +1,47 @@ +/* + * 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; either version 2 of the License, or + * (at your option) any later version. + + * 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. + */ + +#ifndef LINUX_HWRANDOM_H_ +#define LINUX_HWRANDOM_H_ + +#include <linux/list.h> + +/** + * struct hwrng - Hardware Random Number Generator driver + * @name: Unique RNG name. + * @init: Initialization callback (can be NULL). + * @read: New API. drivers can fill up to max bytes of data + * into the buffer. The buffer is aligned for any type. + */ +struct hwrng { + const char *name; + int (*init)(struct hwrng *rng); + int (*read)(struct hwrng *rng, void *data, size_t max, bool wait); + + struct list_head list; + + struct cdev cdev; + struct device_d *dev; + void *buf; +}; + +/* Register a new Hardware Random Number Generator driver. */ +int hwrng_register(struct device_d *dev, struct hwrng *rng); +int hwrng_get_data(struct hwrng *rng, void *buffer, size_t size, int wait); + +#ifdef CONFIG_HWRNG +struct hwrng *hwrng_get_first(void); +#else +static inline struct hwrng *hwrng_get_first(void) { return ERR_PTR(-ENODEV); }; +#endif + +#endif /* LINUX_HWRANDOM_H_ */ |