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From 53bbc98101781c4c4a6a26e987439088423e1d5e Mon Sep 17 00:00:00 2001
From: popcornmix <popcornmix@gmail.com>
Date: Wed, 3 Jul 2013 00:51:55 +0100
Subject: [PATCH 015/171] Add hwrng (hardware random number generator) driver
---
drivers/char/hw_random/Kconfig | 13 +++-
drivers/char/hw_random/Makefile | 1 +
drivers/char/hw_random/bcm2708-rng.c | 118 +++++++++++++++++++++++++++++++++++
3 files changed, 131 insertions(+), 1 deletion(-)
create mode 100755 drivers/char/hw_random/bcm2708-rng.c
--- a/drivers/char/hw_random/Kconfig
+++ b/drivers/char/hw_random/Kconfig
@@ -90,7 +90,7 @@ config HW_RANDOM_BCM63XX
config HW_RANDOM_BCM2835
tristate "Broadcom BCM2835 Random Number Generator support"
- depends on ARCH_BCM2835
+ depends on ARCH_BCM2835 || ARCH_BCM2708 || ARCH_BCM2709
default HW_RANDOM
---help---
This driver provides kernel-side support for the Random Number
@@ -333,6 +333,17 @@ 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 || ARCH_BCM2709)
+ ---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
@@ -4,6 +4,7 @@
obj-$(CONFIG_HW_RANDOM) += rng-core.o
rng-core-y := core.o
+obj-$(CONFIG_HW_RANDOM_BCM2708) += bcm2708-rng.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
--- /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");
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