diff options
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/char/hw_random/Kconfig | 12 | ||||
| -rw-r--r-- | drivers/char/hw_random/Makefile | 1 | ||||
| -rw-r--r-- | drivers/char/hw_random/bcm2835-rng.c | 113 |
3 files changed, 126 insertions, 0 deletions
diff --git a/drivers/char/hw_random/Kconfig b/drivers/char/hw_random/Kconfig index c5a0262251b..2f9dbf7568f 100644 --- a/drivers/char/hw_random/Kconfig +++ b/drivers/char/hw_random/Kconfig @@ -86,6 +86,18 @@ config HW_RANDOM_BCM63XX If unusure, say Y. +config HW_RANDOM_BCM2835 + tristate "Broadcom BCM2835 Random Number Generator support" + depends on HW_RANDOM && ARCH_BCM2835 + default HW_RANDOM + ---help--- + This driver provides kernel-side support for the Random Number + Generator hardware found on the Broadcom BCM2835 SoCs. + + To compile this driver as a module, choose M here: the + module will be called bcm2835-rng + + If unsure, say Y. config HW_RANDOM_GEODE tristate "AMD Geode HW Random Number Generator support" diff --git a/drivers/char/hw_random/Makefile b/drivers/char/hw_random/Makefile index 1fd7eec9fbf..bed467c9300 100644 --- a/drivers/char/hw_random/Makefile +++ b/drivers/char/hw_random/Makefile @@ -26,3 +26,4 @@ obj-$(CONFIG_HW_RANDOM_PPC4XX) += ppc4xx-rng.o obj-$(CONFIG_HW_RANDOM_PSERIES) += pseries-rng.o obj-$(CONFIG_HW_RANDOM_EXYNOS) += exynos-rng.o obj-$(CONFIG_HW_RANDOM_TPM) += tpm-rng.o +obj-$(CONFIG_HW_RANDOM_BCM2835) += bcm2835-rng.o diff --git a/drivers/char/hw_random/bcm2835-rng.c b/drivers/char/hw_random/bcm2835-rng.c new file mode 100644 index 00000000000..eb7f14725eb --- /dev/null +++ b/drivers/char/hw_random/bcm2835-rng.c @@ -0,0 +1,113 @@ +/** + * Copyright (c) 2010-2012 Broadcom. All rights reserved. + * Copyright (c) 2013 Lubomir Rintel + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License ("GPL") + * version 2, as published by the Free Software Foundation. + */ + +#include <linux/hw_random.h> +#include <linux/init.h> +#include <linux/io.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/of_address.h> +#include <linux/of_platform.h> +#include <linux/platform_device.h> +#include <linux/printk.h> + +#define RNG_CTRL 0x0 +#define RNG_STATUS 0x4 +#define RNG_DATA 0x8 + +/* enable rng */ +#define RNG_RBGEN 0x1 + +/* the initial numbers generated are "less random" so will be discarded */ +#define RNG_WARMUP_COUNT 0x40000 + +static int bcm2835_rng_read(struct hwrng *rng, void *buf, size_t max, + bool wait) +{ + void __iomem *rng_base = (void __iomem *)rng->priv; + + while ((__raw_readl(rng_base + RNG_STATUS) >> 24) == 0) { + if (!wait) + return 0; + cpu_relax(); + } + + *(u32 *)buf = __raw_readl(rng_base + RNG_DATA); + return sizeof(u32); +} + +static struct hwrng bcm2835_rng_ops = { + .name = "bcm2835", + .read = bcm2835_rng_read, +}; + +static int bcm2835_rng_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct device_node *np = dev->of_node; + void __iomem *rng_base; + int err; + + /* map peripheral */ + rng_base = of_iomap(np, 0); + if (!rng_base) { + dev_err(dev, "failed to remap rng regs"); + return -ENODEV; + } + bcm2835_rng_ops.priv = (unsigned long)rng_base; + + /* register driver */ + err = hwrng_register(&bcm2835_rng_ops); + if (err) { + dev_err(dev, "hwrng registration failed\n"); + iounmap(rng_base); + } else { + dev_info(dev, "hwrng registered\n"); + + /* set warm-up count & enable */ + __raw_writel(RNG_WARMUP_COUNT, rng_base + RNG_STATUS); + __raw_writel(RNG_RBGEN, rng_base + RNG_CTRL); + } + return err; +} + +static int bcm2835_rng_remove(struct platform_device *pdev) +{ + void __iomem *rng_base = (void __iomem *)bcm2835_rng_ops.priv; + + /* disable rng hardware */ + __raw_writel(0, rng_base + RNG_CTRL); + + /* unregister driver */ + hwrng_unregister(&bcm2835_rng_ops); + iounmap(rng_base); + + return 0; +} + +static const struct of_device_id bcm2835_rng_of_match[] = { + { .compatible = "brcm,bcm2835-rng", }, + {}, +}; +MODULE_DEVICE_TABLE(of, bcm2835_rng_of_match); + +static struct platform_driver bcm2835_rng_driver = { + .driver = { + .name = "bcm2835-rng", + .owner = THIS_MODULE, + .of_match_table = bcm2835_rng_of_match, + }, + .probe = bcm2835_rng_probe, + .remove = bcm2835_rng_remove, +}; +module_platform_driver(bcm2835_rng_driver); + +MODULE_AUTHOR("Lubomir Rintel <lkundrak@v3.sk>"); +MODULE_DESCRIPTION("BCM2835 Random Number Generator (RNG) driver"); +MODULE_LICENSE("GPLv2"); |