target/linux/bcm27xx/patches-6.1/950-0846-hwrng-iproc-rng200-Add-BCM2838-support.patch

   1 From e079555a4c68356e58249cfc041b28f6eb455bd5 Mon Sep 17 00:00:00 2001
   2 From: Stefan Wahren <wahrenst@gmx.net>
   3 Date: Sat, 4 May 2019 17:06:15 +0200
   4 Subject: [PATCH] hwrng: iproc-rng200: Add BCM2838 support
   5
   6 The HWRNG on the BCM2838 is compatible to iproc-rng200, so add the
   7 support to this driver instead of bcm2835-rng.
   8
   9 Signed-off-by: Stefan Wahren <wahrenst@gmx.net>
  10
  11 hwrng: iproc-rng200: Correct SoC name
  12
  13 The Pi 4 SoC is called BCM2711, not BCM2838.
  14
  15 Fixes: "hwrng: iproc-rng200: Add BCM2838 support"
  16
  17 Signed-off-by: Phil Elwell <phil@raspberrypi.com>
  18 ---
  19  drivers/char/hw_random/Kconfig        |  2 +-
  20  drivers/char/hw_random/iproc-rng200.c | 79 ++++++++++++++++++++++++++-
  21  2 files changed, 77 insertions(+), 4 deletions(-)
  22
  23 --- a/drivers/char/hw_random/Kconfig
  24 +++ b/drivers/char/hw_random/Kconfig
  25 @@ -104,7 +104,7 @@ config HW_RANDOM_IPROC_RNG200
  26         default HW_RANDOM
  27         help
  28           This driver provides kernel-side support for the RNG200
  29 -         hardware found on the Broadcom iProc and STB SoCs.
  30 +         hardware found on the Broadcom iProc, BCM2711 and STB SoCs.
  31
  32           To compile this driver as a module, choose M here: the
  33           module will be called iproc-rng200
  34 --- a/drivers/char/hw_random/iproc-rng200.c
  35 +++ b/drivers/char/hw_random/iproc-rng200.c
  36 @@ -14,6 +14,7 @@
  37  #include <linux/module.h>
  38  #include <linux/of_address.h>
  39  #include <linux/of_platform.h>
  40 +#include <linux/of.h>
  41  #include <linux/platform_device.h>
  42  #include <linux/delay.h>
  43
  44 @@ -21,6 +22,7 @@
  45  #define RNG_CTRL_OFFSET                                        0x00
  46  #define RNG_CTRL_RNG_RBGEN_MASK                                0x00001FFF
  47  #define RNG_CTRL_RNG_RBGEN_ENABLE                      0x00000001
  48 +#define RNG_CTRL_RNG_DIV_CTRL_SHIFT                    13
  49
  50  #define RNG_SOFT_RESET_OFFSET                          0x04
  51  #define RNG_SOFT_RESET                                 0x00000001
  52 @@ -28,16 +30,23 @@
  53  #define RBG_SOFT_RESET_OFFSET                          0x08
  54  #define RBG_SOFT_RESET                                 0x00000001
  55
  56 +#define RNG_TOTAL_BIT_COUNT_OFFSET                     0x0C
  57 +
  58 +#define RNG_TOTAL_BIT_COUNT_THRESHOLD_OFFSET           0x10
  59 +
  60  #define RNG_INT_STATUS_OFFSET                          0x18
  61  #define RNG_INT_STATUS_MASTER_FAIL_LOCKOUT_IRQ_MASK    0x80000000
  62  #define RNG_INT_STATUS_STARTUP_TRANSITIONS_MET_IRQ_MASK        0x00020000
  63  #define RNG_INT_STATUS_NIST_FAIL_IRQ_MASK              0x00000020
  64  #define RNG_INT_STATUS_TOTAL_BITS_COUNT_IRQ_MASK       0x00000001
  65
  66 +#define RNG_INT_ENABLE_OFFSET                          0x1C
  67 +
  68  #define RNG_FIFO_DATA_OFFSET                           0x20
  69
  70  #define RNG_FIFO_COUNT_OFFSET                          0x24
  71  #define RNG_FIFO_COUNT_RNG_FIFO_COUNT_MASK             0x000000FF
  72 +#define RNG_FIFO_COUNT_RNG_FIFO_THRESHOLD_SHIFT                8
  73
  74  struct iproc_rng200_dev {
  75         struct hwrng rng;
  76 @@ -158,6 +167,64 @@ static int iproc_rng200_init(struct hwrn
  77         return 0;
  78  }
  79
  80 +static int bcm2711_rng200_read(struct hwrng *rng, void *buf, size_t max,
  81 +                              bool wait)
  82 +{
  83 +       struct iproc_rng200_dev *priv = to_rng_priv(rng);
  84 +       u32 max_words = max / sizeof(u32);
  85 +       u32 num_words, count, val;
  86 +
  87 +       /* ensure warm up period has elapsed */
  88 +       while (1) {
  89 +               val = ioread32(priv->base + RNG_TOTAL_BIT_COUNT_OFFSET);
  90 +               if (val > 16)
  91 +                       break;
  92 +               cpu_relax();
  93 +       }
  94 +
  95 +       /* ensure fifo is not empty */
  96 +       while (1) {
  97 +               num_words = ioread32(priv->base + RNG_FIFO_COUNT_OFFSET) &
  98 +                           RNG_FIFO_COUNT_RNG_FIFO_COUNT_MASK;
  99 +               if (num_words)
 100 +                       break;
 101 +               if (!wait)
 102 +                       return 0;
 103 +               cpu_relax();
 104 +       }
 105 +
 106 +       if (num_words > max_words)
 107 +               num_words = max_words;
 108 +
 109 +       for (count = 0; count < num_words; count++) {
 110 +               ((u32 *)buf)[count] = ioread32(priv->base +
 111 +                                              RNG_FIFO_DATA_OFFSET);
 112 +       }
 113 +
 114 +       return num_words * sizeof(u32);
 115 +}
 116 +
 117 +static int bcm2711_rng200_init(struct hwrng *rng)
 118 +{
 119 +       struct iproc_rng200_dev *priv = to_rng_priv(rng);
 120 +       uint32_t val;
 121 +
 122 +       if (ioread32(priv->base + RNG_CTRL_OFFSET) & RNG_CTRL_RNG_RBGEN_MASK)
 123 +               return 0;
 124 +
 125 +       /* initial numbers generated are "less random" so will be discarded */
 126 +       val = 0x40000;
 127 +       iowrite32(val, priv->base + RNG_TOTAL_BIT_COUNT_THRESHOLD_OFFSET);
 128 +       /* min fifo count to generate full interrupt */
 129 +       val = 2 << RNG_FIFO_COUNT_RNG_FIFO_THRESHOLD_SHIFT;
 130 +       iowrite32(val, priv->base + RNG_FIFO_COUNT_OFFSET);
 131 +       /* enable the rng - 1Mhz sample rate */
 132 +       val = (0x3 << RNG_CTRL_RNG_DIV_CTRL_SHIFT) | RNG_CTRL_RNG_RBGEN_MASK;
 133 +       iowrite32(val, priv->base + RNG_CTRL_OFFSET);
 134 +
 135 +       return 0;
 136 +}
 137 +
 138  static void iproc_rng200_cleanup(struct hwrng *rng)
 139  {
 140         struct iproc_rng200_dev *priv = to_rng_priv(rng);
 141 @@ -184,11 +251,17 @@ static int iproc_rng200_probe(struct pla
 142
 143         dev_set_drvdata(dev, priv);
 144
 145 -       priv->rng.name = "iproc-rng200";
 146 -       priv->rng.read = iproc_rng200_read;
 147 -       priv->rng.init = iproc_rng200_init;
 148 +       priv->rng.name = pdev->name;
 149         priv->rng.cleanup = iproc_rng200_cleanup;
 150
 151 +       if (of_device_is_compatible(dev->of_node, "brcm,bcm2711-rng200")) {
 152 +               priv->rng.init = bcm2711_rng200_init;
 153 +               priv->rng.read = bcm2711_rng200_read;
 154 +       } else {
 155 +               priv->rng.init = iproc_rng200_init;
 156 +               priv->rng.read = iproc_rng200_read;
 157 +       }
 158 +
 159         /* Register driver */
 160         ret = devm_hwrng_register(dev, &priv->rng);
 161         if (ret) {