From 225e1250dfcec7b09493b6a86bdeaab9f2669221 Mon Sep 17 00:00:00 2001 From: popcornmix <popcornmix@gmail.com> Date: Wed, 3 Jul 2013 00:51:55 +0100 Subject: [PATCH 014/114] Add hwrng (hardware random number generator) driver --- drivers/char/hw_random/Kconfig | 11 ++++ drivers/char/hw_random/Makefile | 1 + drivers/char/hw_random/bcm2708-rng.c | 118 +++++++++++++++++++++++++++++++++++ 3 files changed, 130 insertions(+) create mode 100755 drivers/char/hw_random/bcm2708-rng.c --- a/drivers/char/hw_random/Kconfig +++ b/drivers/char/hw_random/Kconfig @@ -320,6 +320,17 @@ config HW_RANDOM_TPM If unsure, say Y. +config HW_RANDOM_BCM2708 + tristate "BCM2708 generic true random number generator support" + depends on HW_RANDOM && ARCH_BCM2708 + ---help--- + This driver provides the kernel-side support for the BCM2708 hardware. + + To compile this driver as a module, choose M here: the + module will be called bcm2708-rng. + + If unsure, say N. + config HW_RANDOM_MSM tristate "Qualcomm SoCs Random Number Generator support" depends on HW_RANDOM && ARCH_QCOM --- a/drivers/char/hw_random/Makefile +++ b/drivers/char/hw_random/Makefile @@ -28,5 +28,6 @@ obj-$(CONFIG_HW_RANDOM_POWERNV) += power obj-$(CONFIG_HW_RANDOM_EXYNOS) += exynos-rng.o obj-$(CONFIG_HW_RANDOM_TPM) += tpm-rng.o obj-$(CONFIG_HW_RANDOM_BCM2835) += bcm2835-rng.o +obj-$(CONFIG_HW_RANDOM_BCM2708) += bcm2708-rng.o obj-$(CONFIG_HW_RANDOM_MSM) += msm-rng.o obj-$(CONFIG_HW_RANDOM_XGENE) += xgene-rng.o --- /dev/null +++ b/drivers/char/hw_random/bcm2708-rng.c @@ -0,0 +1,118 @@ +/** + * Copyright (c) 2010-2012 Broadcom. All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions, and the following disclaimer, + * without modification. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. The names of the above-listed copyright holders may not be used + * to endorse or promote products derived from this software without + * specific prior written permission. + * + * ALTERNATIVELY, this software may be distributed under the terms of the + * GNU General Public License ("GPL") version 2, as published by the Free + * Software Foundation. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS + * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, + * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR + * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR + * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, + * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, + * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR + * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF + * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING + * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS + * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ + +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/init.h> +#include <linux/hw_random.h> +#include <linux/printk.h> + +#include <asm/io.h> +#include <mach/hardware.h> +#include <mach/platform.h> + +#define RNG_CTRL (0x0) +#define RNG_STATUS (0x4) +#define RNG_DATA (0x8) +#define RNG_FF_THRESHOLD (0xc) + +/* enable rng */ +#define RNG_RBGEN 0x1 +/* double speed, less random mode */ +#define RNG_RBG2X 0x2 + +/* the initial numbers generated are "less random" so will be discarded */ +#define RNG_WARMUP_COUNT 0x40000 + +static int bcm2708_rng_data_read(struct hwrng *rng, u32 *buffer) +{ + void __iomem *rng_base = (void __iomem *)rng->priv; + unsigned words; + /* wait for a random number to be in fifo */ + do { + words = __raw_readl(rng_base + RNG_STATUS)>>24; + } + while (words == 0); + /* read the random number */ + *buffer = __raw_readl(rng_base + RNG_DATA); + return 4; +} + +static struct hwrng bcm2708_rng_ops = { + .name = "bcm2708", + .data_read = bcm2708_rng_data_read, +}; + +static int __init bcm2708_rng_init(void) +{ + void __iomem *rng_base; + int err; + + /* map peripheral */ + rng_base = ioremap(RNG_BASE, 0x10); + pr_info("bcm2708_rng_init=%p\n", rng_base); + if (!rng_base) { + pr_err("bcm2708_rng_init failed to ioremap\n"); + return -ENOMEM; + } + bcm2708_rng_ops.priv = (unsigned long)rng_base; + + /* set warm-up count & enable */ + __raw_writel(RNG_WARMUP_COUNT, rng_base + RNG_STATUS); + __raw_writel(RNG_RBGEN, rng_base + RNG_CTRL); + + /* register driver */ + err = hwrng_register(&bcm2708_rng_ops); + if (err) { + pr_err("bcm2708_rng_init hwrng_register()=%d\n", err); + iounmap(rng_base); + } + return err; +} + +static void __exit bcm2708_rng_exit(void) +{ + void __iomem *rng_base = (void __iomem *)bcm2708_rng_ops.priv; + pr_info("bcm2708_rng_exit\n"); + /* disable rng hardware */ + __raw_writel(0, rng_base + RNG_CTRL); + /* unregister driver */ + hwrng_unregister(&bcm2708_rng_ops); + iounmap(rng_base); +} + +module_init(bcm2708_rng_init); +module_exit(bcm2708_rng_exit); + +MODULE_DESCRIPTION("BCM2708 H/W Random Number Generator (RNG) driver"); +MODULE_LICENSE("GPL and additional rights");