target/linux/brcm2708/patches-4.1/0015-Add-hwrng-hardware-random-number-generator-driver.patch

   1 From 53bbc98101781c4c4a6a26e987439088423e1d5e Mon Sep 17 00:00:00 2001
   2 From: popcornmix <popcornmix@gmail.com>
   3 Date: Wed, 3 Jul 2013 00:51:55 +0100
   4 Subject: [PATCH 015/171] Add hwrng (hardware random number generator) driver
   5
   6 ---
   7  drivers/char/hw_random/Kconfig       |  13 +++-
   8  drivers/char/hw_random/Makefile      |   1 +
   9  drivers/char/hw_random/bcm2708-rng.c | 118 +++++++++++++++++++++++++++++++++++
  10  3 files changed, 131 insertions(+), 1 deletion(-)
  11  create mode 100755 drivers/char/hw_random/bcm2708-rng.c
  12
  13 --- a/drivers/char/hw_random/Kconfig
  14 +++ b/drivers/char/hw_random/Kconfig
  15 @@ -90,7 +90,7 @@ config HW_RANDOM_BCM63XX
  16
  17  config HW_RANDOM_BCM2835
  18         tristate "Broadcom BCM2835 Random Number Generator support"
  19 -       depends on ARCH_BCM2835
  20 +       depends on ARCH_BCM2835 || ARCH_BCM2708 || ARCH_BCM2709
  21         default HW_RANDOM
  22         ---help---
  23           This driver provides kernel-side support for the Random Number
  24 @@ -333,6 +333,17 @@ config HW_RANDOM_TPM
  25
  26           If unsure, say Y.
  27
  28 +config HW_RANDOM_BCM2708
  29 +       tristate "BCM2708 generic true random number generator support"
  30 +       depends on HW_RANDOM && (ARCH_BCM2708 || ARCH_BCM2709)
  31 +       ---help---
  32 +        This driver provides the kernel-side support for the BCM2708 hardware.
  33 +
  34 +        To compile this driver as a module, choose M here: the
  35 +        module will be called bcm2708-rng.
  36 +
  37 +        If unsure, say N.
  38 +
  39  config HW_RANDOM_MSM
  40         tristate "Qualcomm SoCs Random Number Generator support"
  41         depends on HW_RANDOM && ARCH_QCOM
  42 --- a/drivers/char/hw_random/Makefile
  43 +++ b/drivers/char/hw_random/Makefile
  44 @@ -4,6 +4,7 @@
  45
  46  obj-$(CONFIG_HW_RANDOM) += rng-core.o
  47  rng-core-y := core.o
  48 +obj-$(CONFIG_HW_RANDOM_BCM2708) += bcm2708-rng.o
  49  obj-$(CONFIG_HW_RANDOM_TIMERIOMEM) += timeriomem-rng.o
  50  obj-$(CONFIG_HW_RANDOM_INTEL) += intel-rng.o
  51  obj-$(CONFIG_HW_RANDOM_AMD) += amd-rng.o
  52 --- /dev/null
  53 +++ b/drivers/char/hw_random/bcm2708-rng.c
  54 @@ -0,0 +1,118 @@
  55 +/**
  56 + * Copyright (c) 2010-2012 Broadcom. All rights reserved.
  57 + *
  58 + * Redistribution and use in source and binary forms, with or without
  59 + * modification, are permitted provided that the following conditions
  60 + * are met:
  61 + * 1. Redistributions of source code must retain the above copyright
  62 + *    notice, this list of conditions, and the following disclaimer,
  63 + *    without modification.
  64 + * 2. Redistributions in binary form must reproduce the above copyright
  65 + *    notice, this list of conditions and the following disclaimer in the
  66 + *    documentation and/or other materials provided with the distribution.
  67 + * 3. The names of the above-listed copyright holders may not be used
  68 + *    to endorse or promote products derived from this software without
  69 + *    specific prior written permission.
  70 + *
  71 + * ALTERNATIVELY, this software may be distributed under the terms of the
  72 + * GNU General Public License ("GPL") version 2, as published by the Free
  73 + * Software Foundation.
  74 + *
  75 + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
  76 + * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
  77 + * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  78 + * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
  79 + * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  80 + * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  81 + * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  82 + * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
  83 + * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  84 + * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  85 + * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  86 + */
  87 +
  88 +#include <linux/kernel.h>
  89 +#include <linux/module.h>
  90 +#include <linux/init.h>
  91 +#include <linux/hw_random.h>
  92 +#include <linux/printk.h>
  93 +
  94 +#include <asm/io.h>
  95 +#include <mach/hardware.h>
  96 +#include <mach/platform.h>
  97 +
  98 +#define RNG_CTRL               (0x0)
  99 +#define RNG_STATUS             (0x4)
 100 +#define RNG_DATA               (0x8)
 101 +#define RNG_FF_THRESHOLD       (0xc)
 102 +
 103 +/* enable rng */
 104 +#define RNG_RBGEN               0x1
 105 +/* double speed, less random mode */
 106 +#define RNG_RBG2X               0x2
 107 +
 108 +/* the initial numbers generated are "less random" so will be discarded */
 109 +#define RNG_WARMUP_COUNT      0x40000
 110 +
 111 +static int bcm2708_rng_data_read(struct hwrng *rng, u32 *buffer)
 112 +{
 113 +       void __iomem *rng_base = (void __iomem *)rng->priv;
 114 +       unsigned words;
 115 +       /* wait for a random number to be in fifo */
 116 +        do {
 117 +               words = __raw_readl(rng_base + RNG_STATUS)>>24;
 118 +       }
 119 +        while (words == 0);
 120 +       /* read the random number */
 121 +       *buffer = __raw_readl(rng_base + RNG_DATA);
 122 +       return 4;
 123 +}
 124 +
 125 +static struct hwrng bcm2708_rng_ops = {
 126 +       .name           = "bcm2708",
 127 +       .data_read      = bcm2708_rng_data_read,
 128 +};
 129 +
 130 +static int __init bcm2708_rng_init(void)
 131 +{
 132 +       void __iomem *rng_base;
 133 +       int err;
 134 +
 135 +       /* map peripheral */
 136 +       rng_base = ioremap(RNG_BASE, 0x10);
 137 +       pr_info("bcm2708_rng_init=%p\n", rng_base);
 138 +       if (!rng_base) {
 139 +               pr_err("bcm2708_rng_init failed to ioremap\n");
 140 +               return -ENOMEM;
 141 +       }
 142 +       bcm2708_rng_ops.priv = (unsigned long)rng_base;
 143 +
 144 +       /* set warm-up count & enable */
 145 +       __raw_writel(RNG_WARMUP_COUNT, rng_base + RNG_STATUS);
 146 +       __raw_writel(RNG_RBGEN, rng_base + RNG_CTRL);
 147 +
 148 +       /* register driver */
 149 +       err = hwrng_register(&bcm2708_rng_ops);
 150 +       if (err) {
 151 +               pr_err("bcm2708_rng_init hwrng_register()=%d\n", err);
 152 +               iounmap(rng_base);
 153 +       }
 154 +       return err;
 155 +}
 156 +
 157 +static void __exit bcm2708_rng_exit(void)
 158 +{
 159 +       void __iomem *rng_base = (void __iomem *)bcm2708_rng_ops.priv;
 160 +       pr_info("bcm2708_rng_exit\n");
 161 +       /* disable rng hardware */
 162 +       __raw_writel(0, rng_base + RNG_CTRL);
 163 +       /* unregister driver */
 164 +       hwrng_unregister(&bcm2708_rng_ops);
 165 +       iounmap(rng_base);
 166 +}
 167 +
 168 +module_init(bcm2708_rng_init);
 169 +module_exit(bcm2708_rng_exit);
 170 +
 171 +MODULE_DESCRIPTION("BCM2708 H/W Random Number Generator (RNG) driver");
 172 +MODULE_LICENSE("GPL and additional rights");