target/linux/brcm2708/patches-3.18/0014-Add-hwrng-hardware-random-number-generator-driver.patch

   1 From 225e1250dfcec7b09493b6a86bdeaab9f2669221 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 014/114] Add hwrng (hardware random number generator) driver
   5
   6 ---
   7  drivers/char/hw_random/Kconfig       |  11 ++++
   8  drivers/char/hw_random/Makefile      |   1 +
   9  drivers/char/hw_random/bcm2708-rng.c | 118 +++++++++++++++++++++++++++++++++++
  10  3 files changed, 130 insertions(+)
  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 @@ -320,6 +320,17 @@ config HW_RANDOM_TPM
  16
  17           If unsure, say Y.
  18
  19 +config HW_RANDOM_BCM2708
  20 +       tristate "BCM2708 generic true random number generator support"
  21 +       depends on HW_RANDOM && ARCH_BCM2708
  22 +       ---help---
  23 +        This driver provides the kernel-side support for the BCM2708 hardware.
  24 +
  25 +        To compile this driver as a module, choose M here: the
  26 +        module will be called bcm2708-rng.
  27 +
  28 +        If unsure, say N.
  29 +
  30  config HW_RANDOM_MSM
  31         tristate "Qualcomm SoCs Random Number Generator support"
  32         depends on HW_RANDOM && ARCH_QCOM
  33 --- a/drivers/char/hw_random/Makefile
  34 +++ b/drivers/char/hw_random/Makefile
  35 @@ -28,5 +28,6 @@ obj-$(CONFIG_HW_RANDOM_POWERNV) += power
  36  obj-$(CONFIG_HW_RANDOM_EXYNOS) += exynos-rng.o
  37  obj-$(CONFIG_HW_RANDOM_TPM) += tpm-rng.o
  38  obj-$(CONFIG_HW_RANDOM_BCM2835) += bcm2835-rng.o
  39 +obj-$(CONFIG_HW_RANDOM_BCM2708) += bcm2708-rng.o
  40  obj-$(CONFIG_HW_RANDOM_MSM) += msm-rng.o
  41  obj-$(CONFIG_HW_RANDOM_XGENE) += xgene-rng.o
  42 --- /dev/null
  43 +++ b/drivers/char/hw_random/bcm2708-rng.c
  44 @@ -0,0 +1,118 @@
  45 +/**
  46 + * Copyright (c) 2010-2012 Broadcom. All rights reserved.
  47 + *
  48 + * Redistribution and use in source and binary forms, with or without
  49 + * modification, are permitted provided that the following conditions
  50 + * are met:
  51 + * 1. Redistributions of source code must retain the above copyright
  52 + *    notice, this list of conditions, and the following disclaimer,
  53 + *    without modification.
  54 + * 2. Redistributions in binary form must reproduce the above copyright
  55 + *    notice, this list of conditions and the following disclaimer in the
  56 + *    documentation and/or other materials provided with the distribution.
  57 + * 3. The names of the above-listed copyright holders may not be used
  58 + *    to endorse or promote products derived from this software without
  59 + *    specific prior written permission.
  60 + *
  61 + * ALTERNATIVELY, this software may be distributed under the terms of the
  62 + * GNU General Public License ("GPL") version 2, as published by the Free
  63 + * Software Foundation.
  64 + *
  65 + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
  66 + * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
  67 + * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  68 + * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
  69 + * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  70 + * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  71 + * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  72 + * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
  73 + * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  74 + * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  75 + * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  76 + */
  77 +
  78 +#include <linux/kernel.h>
  79 +#include <linux/module.h>
  80 +#include <linux/init.h>
  81 +#include <linux/hw_random.h>
  82 +#include <linux/printk.h>
  83 +
  84 +#include <asm/io.h>
  85 +#include <mach/hardware.h>
  86 +#include <mach/platform.h>
  87 +
  88 +#define RNG_CTRL               (0x0)
  89 +#define RNG_STATUS             (0x4)
  90 +#define RNG_DATA               (0x8)
  91 +#define RNG_FF_THRESHOLD       (0xc)
  92 +
  93 +/* enable rng */
  94 +#define RNG_RBGEN               0x1
  95 +/* double speed, less random mode */
  96 +#define RNG_RBG2X               0x2
  97 +
  98 +/* the initial numbers generated are "less random" so will be discarded */
  99 +#define RNG_WARMUP_COUNT      0x40000
 100 +
 101 +static int bcm2708_rng_data_read(struct hwrng *rng, u32 *buffer)
 102 +{
 103 +       void __iomem *rng_base = (void __iomem *)rng->priv;
 104 +       unsigned words;
 105 +       /* wait for a random number to be in fifo */
 106 +        do {
 107 +               words = __raw_readl(rng_base + RNG_STATUS)>>24;
 108 +       }
 109 +        while (words == 0);
 110 +       /* read the random number */
 111 +       *buffer = __raw_readl(rng_base + RNG_DATA);
 112 +       return 4;
 113 +}
 114 +
 115 +static struct hwrng bcm2708_rng_ops = {
 116 +       .name           = "bcm2708",
 117 +       .data_read      = bcm2708_rng_data_read,
 118 +};
 119 +
 120 +static int __init bcm2708_rng_init(void)
 121 +{
 122 +       void __iomem *rng_base;
 123 +       int err;
 124 +
 125 +       /* map peripheral */
 126 +       rng_base = ioremap(RNG_BASE, 0x10);
 127 +       pr_info("bcm2708_rng_init=%p\n", rng_base);
 128 +       if (!rng_base) {
 129 +               pr_err("bcm2708_rng_init failed to ioremap\n");
 130 +               return -ENOMEM;
 131 +       }
 132 +       bcm2708_rng_ops.priv = (unsigned long)rng_base;
 133 +
 134 +       /* set warm-up count & enable */
 135 +       __raw_writel(RNG_WARMUP_COUNT, rng_base + RNG_STATUS);
 136 +       __raw_writel(RNG_RBGEN, rng_base + RNG_CTRL);
 137 +
 138 +       /* register driver */
 139 +       err = hwrng_register(&bcm2708_rng_ops);
 140 +       if (err) {
 141 +               pr_err("bcm2708_rng_init hwrng_register()=%d\n", err);
 142 +               iounmap(rng_base);
 143 +       }
 144 +       return err;
 145 +}
 146 +
 147 +static void __exit bcm2708_rng_exit(void)
 148 +{
 149 +       void __iomem *rng_base = (void __iomem *)bcm2708_rng_ops.priv;
 150 +       pr_info("bcm2708_rng_exit\n");
 151 +       /* disable rng hardware */
 152 +       __raw_writel(0, rng_base + RNG_CTRL);
 153 +       /* unregister driver */
 154 +       hwrng_unregister(&bcm2708_rng_ops);
 155 +       iounmap(rng_base);
 156 +}
 157 +
 158 +module_init(bcm2708_rng_init);
 159 +module_exit(bcm2708_rng_exit);
 160 +
 161 +MODULE_DESCRIPTION("BCM2708 H/W Random Number Generator (RNG) driver");
 162 +MODULE_LICENSE("GPL and additional rights");