From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from metis.ext.pengutronix.de ([2001:67c:670:201:290:27ff:fe1d:cc33]) by bombadil.infradead.org with esmtps (Exim 4.87 #1 (Red Hat Linux)) id 1cqcMC-0000sq-Qs for barebox@lists.infradead.org; Wed, 22 Mar 2017 09:15:07 +0000 From: Oleksij Rempel Date: Wed, 22 Mar 2017 10:14:33 +0100 Message-Id: <20170322091439.18187-2-o.rempel@pengutronix.de> In-Reply-To: <20170322091439.18187-1-o.rempel@pengutronix.de> References: <20170322091439.18187-1-o.rempel@pengutronix.de> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "barebox" Errors-To: barebox-bounces+u.kleine-koenig=pengutronix.de@lists.infradead.org Subject: [PATCH v8 1/7] drivers: add simple hw_random implementation To: barebox@lists.infradead.org Cc: Oleksij Rempel , Steffen Trumtrar From: Steffen Trumtrar Add a simple hw_random implementation based on code from Linux v4.5-rc5. All the entropypool initialization stuff is left out and the obsolete data_read/data_present calls are omitted. Signed-off-by: Steffen Trumtrar Signed-off-by: Oleksij Rempel --- drivers/Kconfig | 1 + drivers/Makefile | 1 + drivers/hw_random/Kconfig | 6 +++ drivers/hw_random/Makefile | 1 + drivers/hw_random/core.c | 125 +++++++++++++++++++++++++++++++++++++++++++++ include/linux/hw_random.h | 47 +++++++++++++++++ 6 files changed, 181 insertions(+) create mode 100644 drivers/hw_random/Kconfig create mode 100644 drivers/hw_random/Makefile create mode 100644 drivers/hw_random/core.c create mode 100644 include/linux/hw_random.h diff --git a/drivers/Kconfig b/drivers/Kconfig index cc086ac2d..2f5784a4d 100644 --- a/drivers/Kconfig +++ b/drivers/Kconfig @@ -21,6 +21,7 @@ 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 6a70f6ee1..7e9b80e59 100644 --- a/drivers/Makefile +++ b/drivers/Makefile @@ -20,6 +20,7 @@ obj-y += misc/ obj-y += dma/ obj-y += watchdog/ obj-y += gpio/ +obj-$(CONFIG_HWRNG) += hw_random/ obj-$(CONFIG_OFTREE) += of/ obj-$(CONFIG_W1) += w1/ obj-y += pinctrl/ diff --git a/drivers/hw_random/Kconfig b/drivers/hw_random/Kconfig new file mode 100644 index 000000000..807fcadd3 --- /dev/null +++ b/drivers/hw_random/Kconfig @@ -0,0 +1,6 @@ +menuconfig HWRNG + bool "HWRNG Support" + help + Support for HWRNG(Hardware Random Number Generator) devices. + + If unsure, say no. diff --git a/drivers/hw_random/Makefile b/drivers/hw_random/Makefile new file mode 100644 index 000000000..15307b100 --- /dev/null +++ b/drivers/hw_random/Makefile @@ -0,0 +1 @@ +obj-$(CONFIG_HWRNG) += core.o diff --git a/drivers/hw_random/core.c b/drivers/hw_random/core.c new file mode 100644 index 000000000..ef2a988c7 --- /dev/null +++ b/drivers/hw_random/core.c @@ -0,0 +1,125 @@ +/* + * Copyright (c) 2016 Pengutronix, Steffen Trumtrar + * + * 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 +#include +#include + +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 000000000..bae442166 --- /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 + +/** + * 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_ */ -- 2.11.0 _______________________________________________ barebox mailing list barebox@lists.infradead.org http://lists.infradead.org/mailman/listinfo/barebox