sandbox: rng: Add a random number generator(rng) driver

Add a sandbox driver for random number generation. Mostly aimed at
providing a unit test for rng uclass.

Signed-off-by: Sughosh Ganu <sughosh.ganu@linaro.org>
Reviewed-by: Patrice Chotard <patrice.chotard@st.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

diff --git a/arch/sandbox/dts/test.dts b/arch/sandbox/dts/test.dts
index 57513a449fab24c5169ddfffe4a685cf7f523eb6..4ea8fea674d0148455d1cc1bbb356b369a9fe756 100644 (file)
--- a/arch/sandbox/dts/test.dts
+++ b/arch/sandbox/dts/test.dts
@@ -630,6 +630,10 @@
                reset-names = "other", "test";
        };
 
+       rng {
+               compatible = "sandbox,sandbox-rng";
+       };
+
        rproc_1: rproc@1 {
                compatible = "sandbox,test-processor";
                remoteproc-name = "remoteproc-test-dev1";

diff --git a/drivers/rng/Kconfig b/drivers/rng/Kconfig
index c9c475128edb100cef8faf03dab3ee86cf73b69d..35a3bd192aa94ea1bf210c7e406db4119aad4e28 100644 (file)
--- a/drivers/rng/Kconfig
+++ b/drivers/rng/Kconfig
@@ -6,6 +6,14 @@ config DM_RNG
          This interface is used to initialise the rng device and to
          read the random seed from the device.
 
+config RNG_SANDBOX
+       bool "Sandbox random number generator"
+       depends on SANDBOX && DM_RNG
+       select CONFIG_LIB_RAND
+       help
+         Enable random number generator for sandbox. This is an
+         emulation of a rng device.
+
 config RNG_STM32MP1
        bool "Enable random number generator for STM32MP1"
        depends on ARCH_STM32MP && DM_RNG

diff --git a/drivers/rng/Makefile b/drivers/rng/Makefile
index 699beb383b12c6bd29eed00e6fe88a6add8f8282..35170055415846a59239d46cce93d790a2ad70e7 100644 (file)
--- a/drivers/rng/Makefile
+++ b/drivers/rng/Makefile
@@ -4,4 +4,5 @@
 #
 
 obj-$(CONFIG_DM_RNG) += rng-uclass.o
+obj-$(CONFIG_RNG_SANDBOX) += sandbox_rng.o
 obj-$(CONFIG_RNG_STM32MP1) += stm32mp1_rng.o

diff --git a/drivers/rng/sandbox_rng.c b/drivers/rng/sandbox_rng.c
new file mode 100644 (file)
index 0000000..cd0b0ac
--- /dev/null
+++ b/drivers/rng/sandbox_rng.c
@@ -0,0 +1,56 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2019, Linaro Limited
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <rng.h>
+
+#include <linux/string.h>
+
+static int sandbox_rng_read(struct udevice *dev, void *data, size_t len)
+{
+       unsigned int i, seed, random;
+       unsigned char *buf = data;
+       size_t nrem, nloops;
+
+       if (!len)
+               return 0;
+
+       nloops = len / sizeof(random);
+       seed = get_timer(0) ^ rand();
+       srand(seed);
+
+       for (i = 0, nrem = len; i < nloops; i++) {
+               random = rand();
+               memcpy(buf, &random, sizeof(random));
+               buf += sizeof(random);
+               nrem -= sizeof(random);
+       }
+
+       if (nrem) {
+               random = rand();
+               memcpy(buf, &random, nrem);
+       }
+
+       return 0;
+}
+
+static const struct dm_rng_ops sandbox_rng_ops = {
+       .read = sandbox_rng_read,
+};
+
+static const struct udevice_id sandbox_rng_match[] = {
+       {
+               .compatible = "sandbox,sandbox-rng",
+       },
+       {},
+};
+
+U_BOOT_DRIVER(sandbox_rng) = {
+       .name = "sandbox-rng",
+       .id = UCLASS_RNG,
+       .of_match = sandbox_rng_match,
+       .ops = &sandbox_rng_ops,
+};