target/linux/bmips/patches-5.10/207-hwrng-bcm2835-add-reset-support.patch

   1 From 846cd2c9eee7a99de29c743911cc047fdd56db02 Mon Sep 17 00:00:00 2001
   2 From: =?UTF-8?q?=C3=81lvaro=20Fern=C3=A1ndez=20Rojas?= <noltari@gmail.com>
   3 Date: Mon, 22 Feb 2021 20:41:04 +0100
   4 Subject: [PATCH] hwrng: bcm2835: add reset support
   5 MIME-Version: 1.0
   6 Content-Type: text/plain; charset=UTF-8
   7 Content-Transfer-Encoding: 8bit
   8
   9 BCM6368 devices need to reset the in order to generate true random numbers.
  10 This is what BCM6368 produces without a reset:
  11 root@OpenWrt:/# cat /dev/hwrng | rngtest -c 1000
  12 rngtest 6.10
  13 Copyright (c) 2004 by Henrique de Moraes Holschuh
  14 This is free software; see the source for copying conditions.  There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  15
  16 rngtest: starting FIPS tests...
  17 rngtest: bits received from input: 20000032
  18 rngtest: FIPS 140-2 successes: 0
  19 rngtest: FIPS 140-2 failures: 1000
  20 rngtest: FIPS 140-2(2001-10-10) Monobit: 2
  21 rngtest: FIPS 140-2(2001-10-10) Poker: 1000
  22 rngtest: FIPS 140-2(2001-10-10) Runs: 1000
  23 rngtest: FIPS 140-2(2001-10-10) Long run: 30
  24 rngtest: FIPS 140-2(2001-10-10) Continuous run: 0
  25 rngtest: input channel speed: (min=37.253; avg=320.827; max=635.783)Mibits/s
  26 rngtest: FIPS tests speed: (min=12.141; avg=15.034; max=16.428)Mibits/s
  27 rngtest: Program run time: 1336176 microseconds
  28 cat: write error: Broken pipe
  29
  30 Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
  31 ---
  32  drivers/char/hw_random/bcm2835-rng.c | 10 ++++++++++
  33  1 file changed, 10 insertions(+)
  34
  35 --- a/drivers/char/hw_random/bcm2835-rng.c
  36 +++ b/drivers/char/hw_random/bcm2835-rng.c
  37 @@ -13,6 +13,7 @@
  38  #include <linux/platform_device.h>
  39  #include <linux/printk.h>
  40  #include <linux/clk.h>
  41 +#include <linux/reset.h>
  42
  43  #define RNG_CTRL       0x0
  44  #define RNG_STATUS     0x4
  45 @@ -32,6 +33,7 @@ struct bcm2835_rng_priv {
  46         void __iomem *base;
  47         bool mask_interrupts;
  48         struct clk *clk;
  49 +       struct reset_control *reset;
  50  };
  51
  52  static inline struct bcm2835_rng_priv *to_rng_priv(struct hwrng *rng)
  53 @@ -94,6 +96,10 @@ static int bcm2835_rng_init(struct hwrng
  54                         return ret;
  55         }
  56
  57 +       ret = reset_control_reset(priv->reset);
  58 +       if (ret)
  59 +               return ret;
  60 +
  61         if (priv->mask_interrupts) {
  62                 /* mask the interrupt */
  63                 val = rng_readl(priv, RNG_INT_MASK);
  64 @@ -159,6 +165,10 @@ static int bcm2835_rng_probe(struct plat
  65         if (PTR_ERR(priv->clk) == -EPROBE_DEFER)
  66                 return -EPROBE_DEFER;
  67
  68 +       priv->reset = devm_reset_control_get_optional_exclusive(dev, NULL);
  69 +       if (IS_ERR(priv->reset))
  70 +               return PTR_ERR(priv->reset);
  71 +
  72         priv->rng.name = pdev->name;
  73         priv->rng.init = bcm2835_rng_init;
  74         priv->rng.read = bcm2835_rng_read;