[PATCH v2 0/7] Add a random number generator uclass

[PATCH v2 0/7] Add a random number generator uclass

[Sughosh Ganu]

Add a random number generator(rng) uclass to facilitate adding drivers
for rng devices. I plan to add an implementation of the
EFI_RNG_PROTOCOL, which would get the random number from the rng
uclass -- the protocol would be used by the efi stub for getting a
random number for the kaslr feature.

The patch series also adds a driver for the rng device found on the
stm32mp1 platforms. A dummy rng driver for sandbox has also been
added, along with the unit test for the rng uclass.

Changes since V1:
* Add a SPDX header in rng.h
* Change the UCLASS_DRIVER name from hwrng to rng, consistent with the
  rest of the naming convention
* Handle review comment from Patrice Chotard

Sughosh Ganu (7):
  dm: rng: Add random number generator(rng) uclass
  clk: stm32mp1: Add a clock entry for RNG1 device
  stm32mp1: rng: Add a driver for random number generator(rng) device
  configs: stm32mp15: Enable random number generator(rng) device
  sandbox: rng: Add a random number generator(rng) driver
  configs: sandbox: Enable random number generator(rng) device
  test: rng: Add basic test for random number generator(rng) uclass

 arch/sandbox/dts/test.dts           |   4 +
 configs/sandbox64_defconfig         |   2 +
 configs/sandbox_defconfig           |   2 +
 configs/stm32mp15_basic_defconfig   |   2 +
 configs/stm32mp15_optee_defconfig   |   2 +
 configs/stm32mp15_trusted_defconfig |   2 +
 drivers/Kconfig                     |   2 +
 drivers/Makefile                    |   1 +
 drivers/clk/clk_stm32mp1.c          |   1 +
 drivers/rng/Kconfig                 |  21 +++++
 drivers/rng/Makefile                |   8 ++
 drivers/rng/rng-uclass.c            |  23 ++++++
 drivers/rng/sandbox_rng.c           |  36 ++++++++
 drivers/rng/stm32mp1_rng.c          | 158 ++++++++++++++++++++++++++++++++++++
 include/dm/uclass-id.h              |   1 +
 include/rng.h                       |  30 +++++++
 test/dm/Makefile                    |   1 +
 test/dm/rng.c                       |  26 ++++++
 18 files changed, 322 insertions(+)
 create mode 100644 drivers/rng/Kconfig
 create mode 100644 drivers/rng/Makefile
 create mode 100644 drivers/rng/rng-uclass.c
 create mode 100644 drivers/rng/sandbox_rng.c
 create mode 100644 drivers/rng/stm32mp1_rng.c
 create mode 100644 include/rng.h
 create mode 100644 test/dm/rng.c

-- 
2.7.4

[PATCH v2 1/7] dm: rng: Add random number generator(rng) uclass

[Sughosh Ganu]

Add a uclass for reading a random number seed from a random number
generator device.

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

Changes since V1:
* Add a SPDX header in rng.h
* Change the UCLASS_DRIVER name from hwrng to rng, to be consistent
  with the rest of the naming convention

 drivers/Kconfig          |  2 ++
 drivers/Makefile         |  1 +
 drivers/rng/Kconfig      |  7 +++++++
 drivers/rng/Makefile     |  6 ++++++
 drivers/rng/rng-uclass.c | 23 +++++++++++++++++++++++
 include/dm/uclass-id.h   |  1 +
 include/rng.h            | 30 ++++++++++++++++++++++++++++++
 7 files changed, 70 insertions(+)
 create mode 100644 drivers/rng/Kconfig
 create mode 100644 drivers/rng/Makefile
 create mode 100644 drivers/rng/rng-uclass.c
 create mode 100644 include/rng.h

diff --git a/drivers/Kconfig b/drivers/Kconfig
index 9d99ce0..e34a227 100644
--- a/drivers/Kconfig
+++ b/drivers/Kconfig
@@ -90,6 +90,8 @@ source "drivers/remoteproc/Kconfig"
 
 source "drivers/reset/Kconfig"
 
+source "drivers/rng/Kconfig"
+
 source "drivers/rtc/Kconfig"
 
 source "drivers/scsi/Kconfig"
diff --git a/drivers/Makefile b/drivers/Makefile
index 0d1d6bd..50e5c70 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -114,4 +114,5 @@ obj-$(CONFIG_W1_EEPROM) += w1-eeprom/
 
 obj-$(CONFIG_MACH_PIC32) += ddr/microchip/
 obj-$(CONFIG_DM_HWSPINLOCK) += hwspinlock/
+obj-$(CONFIG_DM_RNG) += rng/
 endif
diff --git a/drivers/rng/Kconfig b/drivers/rng/Kconfig
new file mode 100644
index 0000000..dd44cc0
--- /dev/null
+++ b/drivers/rng/Kconfig
@@ -0,0 +1,7 @@
+config DM_RNG
+	bool "Driver support for Random Number Generator devices"
+	depends on DM
+	help
+	  Enable driver model for random number generator(rng) devices.
+	  This interface is used to initialise the rng device and to
+	  read the random seed from the device.
diff --git a/drivers/rng/Makefile b/drivers/rng/Makefile
new file mode 100644
index 0000000..311705b
--- /dev/null
+++ b/drivers/rng/Makefile
@@ -0,0 +1,6 @@
+# SPDX-License-Identifier: GPL-2.0+
+#
+# Copyright (c) 2019, Linaro Limited
+#
+
+obj-$(CONFIG_DM_RNG) += rng-uclass.o
diff --git a/drivers/rng/rng-uclass.c b/drivers/rng/rng-uclass.c
new file mode 100644
index 0000000..b6af3b8
--- /dev/null
+++ b/drivers/rng/rng-uclass.c
@@ -0,0 +1,23 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (c) 2019, Linaro Limited
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <rng.h>
+
+int dm_rng_read(struct udevice *dev, void *buffer, size_t size)
+{
+	const struct dm_rng_ops *ops = device_get_ops(dev);
+
+	if (!ops->read)
+		return -ENOSYS;
+
+	return ops->read(dev, buffer, size);
+}
+
+UCLASS_DRIVER(rng) = {
+	.name = "rng",
+	.id = UCLASS_RNG,
+};
diff --git a/include/dm/uclass-id.h b/include/dm/uclass-id.h
index 0c563d8..192202d 100644
--- a/include/dm/uclass-id.h
+++ b/include/dm/uclass-id.h
@@ -86,6 +86,7 @@ enum uclass_id {
 	UCLASS_REGULATOR,	/* Regulator device */
 	UCLASS_REMOTEPROC,	/* Remote Processor device */
 	UCLASS_RESET,		/* Reset controller device */
+	UCLASS_RNG,		/* Random Number Generator */
 	UCLASS_RTC,		/* Real time clock device */
 	UCLASS_SCSI,		/* SCSI device */
 	UCLASS_SERIAL,		/* Serial UART */
diff --git a/include/rng.h b/include/rng.h
new file mode 100644
index 0000000..61d5da9
--- /dev/null
+++ b/include/rng.h
@@ -0,0 +1,30 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (c) 2019, Linaro Limited
+ */
+
+#if !defined _RNG_H_
+#define _RNG_H_
+
+#include <dm.h>
+
+/**
+ * dm_rng_read() - read a random number seed from the rng device
+ * @buffer:	input buffer to put the read random seed into
+ * @size:	number of bytes of random seed read
+ *
+ */
+int dm_rng_read(struct udevice *dev, void *buffer, size_t size);
+
+/* struct dm_rng_ops - Operations for the hwrng uclass */
+struct dm_rng_ops {
+	/**
+	 * @read() - read a random number seed
+	 *
+	 * @data:	input buffer to read the random seed
+	 * @max:	total number of bytes to read
+	 */
+	int (*read)(struct udevice *dev, void *data, size_t max);
+};
+
+#endif /* _RNG_H_ */
-- 
2.7.4

[PATCH v2 2/7] clk: stm32mp1: Add a clock entry for RNG1 device

[Sughosh Ganu]

Add an entry for allowing clock enablement for the random number
generator peripheral, RNG1.

Signed-off-by: Sughosh Ganu <sughosh.ganu@linaro.org>
Reviewed-by: Patrice Chotard <patrice.chotard@st.com>
---
 drivers/clk/clk_stm32mp1.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/clk/clk_stm32mp1.c b/drivers/clk/clk_stm32mp1.c
index 3718970..da66bde 100644
--- a/drivers/clk/clk_stm32mp1.c
+++ b/drivers/clk/clk_stm32mp1.c
@@ -563,6 +563,7 @@ static const struct stm32mp1_clk_gate stm32mp1_clk_gate[] = {
 	STM32MP1_CLK_SET_CLR(RCC_MP_AHB4ENSETR, 10, GPIOK, _UNKNOWN_SEL),
 
 	STM32MP1_CLK_SET_CLR(RCC_MP_AHB5ENSETR, 0, GPIOZ, _UNKNOWN_SEL),
+	STM32MP1_CLK_SET_CLR(RCC_MP_AHB5ENSETR, 6, RNG1_K, _UNKNOWN_SEL),
 
 	STM32MP1_CLK_SET_CLR(RCC_MP_AHB6ENSETR, 7, ETHCK_K, _ETH_SEL),
 	STM32MP1_CLK_SET_CLR(RCC_MP_AHB6ENSETR, 8, ETHTX, _UNKNOWN_SEL),
-- 
2.7.4

[PATCH v2 3/7] stm32mp1: rng: Add a driver for random number generator(rng) device

[Sughosh Ganu]

Add a driver for the rng device found on stm32mp1 platforms. The
driver provides a routine for reading the random number seed from the
hardware device.

Signed-off-by: Sughosh Ganu <sughosh.ganu@linaro.org>
---

Changes since V1:
* Handle review comment from Patrice Chotard to remove the 'inited'
  member

 drivers/rng/Kconfig        |   7 ++
 drivers/rng/Makefile       |   1 +
 drivers/rng/stm32mp1_rng.c | 158 +++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 166 insertions(+)
 create mode 100644 drivers/rng/stm32mp1_rng.c

diff --git a/drivers/rng/Kconfig b/drivers/rng/Kconfig
index dd44cc0..5fc11db 100644
--- a/drivers/rng/Kconfig
+++ b/drivers/rng/Kconfig
@@ -5,3 +5,10 @@ config DM_RNG
 	  Enable driver model for random number generator(rng) devices.
 	  This interface is used to initialise the rng device and to
 	  read the random seed from the device.
+
+config RNG_STM32MP1
+       bool "Enable random number generator for STM32MP1"
+       depends on ARCH_STM32MP && DM_RNG
+       default n
+       help
+         Enable STM32MP1 rng driver.
diff --git a/drivers/rng/Makefile b/drivers/rng/Makefile
index 311705b..699beb3 100644
--- a/drivers/rng/Makefile
+++ b/drivers/rng/Makefile
@@ -4,3 +4,4 @@
 #
 
 obj-$(CONFIG_DM_RNG) += rng-uclass.o
+obj-$(CONFIG_RNG_STM32MP1) += stm32mp1_rng.o
diff --git a/drivers/rng/stm32mp1_rng.c b/drivers/rng/stm32mp1_rng.c
new file mode 100644
index 0000000..5cd736d
--- /dev/null
+++ b/drivers/rng/stm32mp1_rng.c
@@ -0,0 +1,158 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2019, Linaro Limited
+ */
+
+#include <common.h>
+#include <clk.h>
+#include <dm.h>
+#include <reset.h>
+#include <rng.h>
+
+#include <asm/io.h>
+#include <linux/iopoll.h>
+#include <linux/kernel.h>
+
+#define RNG_CR 0x00
+#define RNG_CR_RNGEN BIT(2)
+#define RNG_CR_CED BIT(5)
+
+#define RNG_SR 0x04
+#define RNG_SR_SEIS BIT(6)
+#define RNG_SR_CEIS BIT(5)
+#define RNG_SR_SECS BIT(2)
+#define RNG_SR_DRDY BIT(0)
+
+#define RNG_DR 0x08
+
+struct stm32_rng_platdata {
+	fdt_addr_t base;
+	struct clk clk;
+	struct reset_ctl rst;
+};
+
+static int stm32_rng_read(struct udevice *dev, void *data, size_t len)
+{
+	int retval = 0, i;
+	u32 sr, count, reg;
+	size_t increment;
+	struct stm32_rng_platdata *pdata = dev_get_platdata(dev);
+
+	while (len > 0) {
+		retval = readl_poll_timeout(pdata->base + RNG_SR, sr,
+					    sr & RNG_SR_DRDY, 10000);
+		if (retval)
+			return retval;
+
+		if (sr & (RNG_SR_SEIS | RNG_SR_SECS)) {
+			/* As per SoC TRM */
+			clrbits_le32(pdata->base + RNG_SR, RNG_SR_SEIS);
+			for (i = 0; i < 12; i++)
+				readl(pdata->base + RNG_DR);
+			if (readl(pdata->base + RNG_SR) & RNG_SR_SEIS) {
+				printf("RNG Noise");
+				return -EIO;
+			}
+			/* start again */
+			continue;
+		}
+
+		count = 4;
+		while (len && count) {
+			reg = readl(pdata->base + RNG_DR);
+			memcpy(data, &reg, min(len, sizeof(u32)));
+			increment = min(len, sizeof(u32));
+			data += increment;
+			retval += increment;
+			len -= increment;
+			count--;
+		}
+	}
+
+	return retval;
+}
+
+static int stm32_rng_init(struct stm32_rng_platdata *pdata)
+{
+	int err;
+
+	err = clk_enable(&pdata->clk);
+	if (err)
+		return err;
+
+	/* Disable CED */
+	writel(RNG_CR_RNGEN | RNG_CR_CED, pdata->base + RNG_CR);
+
+	/* clear error indicators */
+	writel(0, pdata->base + RNG_SR);
+
+	return 0;
+}
+
+static int stm32_rng_cleanup(struct stm32_rng_platdata *pdata)
+{
+
+	writel(0, pdata->base + RNG_CR);
+
+	return clk_disable(&pdata->clk);
+}
+
+static int stm32_rng_probe(struct udevice *dev)
+{
+	struct stm32_rng_platdata *pdata = dev_get_platdata(dev);
+
+	reset_assert(&pdata->rst);
+	udelay(20);
+	reset_deassert(&pdata->rst);
+
+	return stm32_rng_init(pdata);
+}
+
+static int stm32_rng_remove(struct udevice *dev)
+{
+	struct stm32_rng_platdata *pdata = dev_get_platdata(dev);
+
+	return stm32_rng_cleanup(pdata);
+}
+
+static int stm32_rng_ofdata_to_platdata(struct udevice *dev)
+{
+	struct stm32_rng_platdata *pdata = dev_get_platdata(dev);
+	int err;
+
+	pdata->base = dev_read_addr(dev);
+	if (!pdata->base)
+		return -ENOMEM;
+
+	err = clk_get_by_index(dev, 0, &pdata->clk);
+	if (err)
+		return err;
+
+	err = reset_get_by_index(dev, 0, &pdata->rst);
+	if (err)
+		return err;
+
+	return 0;
+}
+
+static const struct dm_rng_ops stm32_rng_ops = {
+	.read = stm32_rng_read,
+};
+
+static const struct udevice_id stm32_rng_match[] = {
+	{
+		.compatible = "st,stm32-rng",
+	},
+	{},
+};
+
+U_BOOT_DRIVER(stm32_rng) = {
+	.name = "stm32-rng",
+	.id = UCLASS_RNG,
+	.of_match = stm32_rng_match,
+	.ops = &stm32_rng_ops,
+	.probe = stm32_rng_probe,
+	.remove = stm32_rng_remove,
+	.platdata_auto_alloc_size = sizeof(struct stm32_rng_platdata),
+	.ofdata_to_platdata = stm32_rng_ofdata_to_platdata,
+};
-- 
2.7.4

[PATCH v2 4/7] configs: stm32mp15: Enable random number generator(rng) device

[Sughosh Ganu]

Enable support for the rng device on the stm32mp15 configs.

Signed-off-by: Sughosh Ganu <sughosh.ganu@linaro.org>
Reviewed-by: Patrice Chotard <patrice.chotard@st.com>
---
 configs/stm32mp15_basic_defconfig   | 2 ++
 configs/stm32mp15_optee_defconfig   | 2 ++
 configs/stm32mp15_trusted_defconfig | 2 ++
 3 files changed, 6 insertions(+)

diff --git a/configs/stm32mp15_basic_defconfig b/configs/stm32mp15_basic_defconfig
index 14e1127..725381d 100644
--- a/configs/stm32mp15_basic_defconfig
+++ b/configs/stm32mp15_basic_defconfig
@@ -140,3 +140,5 @@ CONFIG_VIDEO_STM32_DSI=y
 CONFIG_VIDEO_STM32_MAX_XRES=1280
 CONFIG_VIDEO_STM32_MAX_YRES=800
 CONFIG_FDT_FIXUP_PARTITIONS=y
+CONFIG_DM_RNG=y
+CONFIG_RNG_STM32MP1=y
diff --git a/configs/stm32mp15_optee_defconfig b/configs/stm32mp15_optee_defconfig
index 791c1a9..5e3c826 100644
--- a/configs/stm32mp15_optee_defconfig
+++ b/configs/stm32mp15_optee_defconfig
@@ -124,3 +124,5 @@ CONFIG_VIDEO_STM32_DSI=y
 CONFIG_VIDEO_STM32_MAX_XRES=1280
 CONFIG_VIDEO_STM32_MAX_YRES=800
 CONFIG_FDT_FIXUP_PARTITIONS=y
+CONFIG_DM_RNG=y
+CONFIG_RNG_STM32MP1=y
diff --git a/configs/stm32mp15_trusted_defconfig b/configs/stm32mp15_trusted_defconfig
index 5556b18..cbdb903 100644
--- a/configs/stm32mp15_trusted_defconfig
+++ b/configs/stm32mp15_trusted_defconfig
@@ -123,3 +123,5 @@ CONFIG_VIDEO_STM32_DSI=y
 CONFIG_VIDEO_STM32_MAX_XRES=1280
 CONFIG_VIDEO_STM32_MAX_YRES=800
 CONFIG_FDT_FIXUP_PARTITIONS=y
+CONFIG_DM_RNG=y
+CONFIG_RNG_STM32MP1=y
-- 
2.7.4

[PATCH v2 5/7] sandbox: rng: Add a random number generator(rng) driver

[Sughosh Ganu]

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>
---
 arch/sandbox/dts/test.dts |  4 ++++
 drivers/rng/Kconfig       |  7 +++++++
 drivers/rng/Makefile      |  1 +
 drivers/rng/sandbox_rng.c | 36 ++++++++++++++++++++++++++++++++++++
 4 files changed, 48 insertions(+)
 create mode 100644 drivers/rng/sandbox_rng.c

diff --git a/arch/sandbox/dts/test.dts b/arch/sandbox/dts/test.dts
index fdb08f2..2c85540 100644
--- a/arch/sandbox/dts/test.dts
+++ b/arch/sandbox/dts/test.dts
@@ -599,6 +599,10 @@
 		reset-names = "other", "test";
 	};
 
+	rng at 0 {
+		compatible = "sandbox,sandbox-rng";
+	};
+
 	rproc_1: rproc at 1 {
 		compatible = "sandbox,test-processor";
 		remoteproc-name = "remoteproc-test-dev1";
diff --git a/drivers/rng/Kconfig b/drivers/rng/Kconfig
index 5fc11db..3a1d3f0 100644
--- a/drivers/rng/Kconfig
+++ b/drivers/rng/Kconfig
@@ -6,6 +6,13 @@ 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
+       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 699beb3..3517005 100644
--- 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
index 0000000..c5be552
--- /dev/null
+++ b/drivers/rng/sandbox_rng.c
@@ -0,0 +1,36 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2019, Linaro Limited
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <rng.h>
+
+static unsigned long random = 0xdeadbeef;
+
+static int sandbox_rng_read(struct udevice *dev, void *data, size_t len)
+{
+	random ^= ~0UL;
+	*(unsigned long *)data = random;
+
+	return sizeof(random);
+}
+
+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,
+};
-- 
2.7.4

[PATCH v2 6/7] configs: sandbox: Enable random number generator(rng) device

[Sughosh Ganu]

Enable support for random number generator on sandbox configs. This is
aimed primarily at adding unit test support for rng uclass.

Signed-off-by: Sughosh Ganu <sughosh.ganu@linaro.org>
Reviewed-by: Patrice Chotard <patrice.chotard@st.com>
---
 configs/sandbox64_defconfig | 2 ++
 configs/sandbox_defconfig   | 2 ++
 2 files changed, 4 insertions(+)

diff --git a/configs/sandbox64_defconfig b/configs/sandbox64_defconfig
index d467841..2ef1097 100644
--- a/configs/sandbox64_defconfig
+++ b/configs/sandbox64_defconfig
@@ -158,6 +158,8 @@ CONFIG_REGULATOR_RK8XX=y
 CONFIG_REGULATOR_S5M8767=y
 CONFIG_DM_REGULATOR_SANDBOX=y
 CONFIG_REGULATOR_TPS65090=y
+CONFIG_DM_RNG=y
+CONFIG_RNG_SANDBOX=y
 CONFIG_DM_PWM=y
 CONFIG_PWM_SANDBOX=y
 CONFIG_RAM=y
diff --git a/configs/sandbox_defconfig b/configs/sandbox_defconfig
index ed7ff78..417d775 100644
--- a/configs/sandbox_defconfig
+++ b/configs/sandbox_defconfig
@@ -179,6 +179,8 @@ CONFIG_REGULATOR_RK8XX=y
 CONFIG_REGULATOR_S5M8767=y
 CONFIG_DM_REGULATOR_SANDBOX=y
 CONFIG_REGULATOR_TPS65090=y
+CONFIG_DM_RNG=y
+CONFIG_RNG_SANDBOX=y
 CONFIG_DM_PWM=y
 CONFIG_PWM_SANDBOX=y
 CONFIG_RAM=y
-- 
2.7.4

[PATCH v2 7/7] test: rng: Add basic test for random number generator(rng) uclass

[Sughosh Ganu]

Add a unit test for testing the rng uclass functionality using the
sandbox rng driver.

Signed-off-by: Sughosh Ganu <sughosh.ganu@linaro.org>
Reviewed-by: Patrice Chotard <patrice.chotard@st.com>
---
 test/dm/Makefile |  1 +
 test/dm/rng.c    | 26 ++++++++++++++++++++++++++
 2 files changed, 27 insertions(+)
 create mode 100644 test/dm/rng.c

diff --git a/test/dm/Makefile b/test/dm/Makefile
index 0c2fd5c..f61bf65 100644
--- a/test/dm/Makefile
+++ b/test/dm/Makefile
@@ -65,4 +65,5 @@ obj-$(CONFIG_VIRTIO_SANDBOX) += virtio.o
 obj-$(CONFIG_DMA) += dma.o
 obj-$(CONFIG_DM_MDIO) += mdio.o
 obj-$(CONFIG_DM_MDIO_MUX) += mdio_mux.o
+obj-$(CONFIG_DM_RNG) += rng.o
 endif
diff --git a/test/dm/rng.c b/test/dm/rng.c
new file mode 100644
index 0000000..879e80a
--- /dev/null
+++ b/test/dm/rng.c
@@ -0,0 +1,26 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2019, Linaro Limited
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <rng.h>
+#include <dm/test.h>
+#include <test/ut.h>
+
+/* Basic test of the rng uclass */
+static int dm_test_rng_read(struct unit_test_state *uts)
+{
+	unsigned long val1 = 0, val2 = 0;
+	struct udevice *dev;
+
+	ut_assertok(uclass_get_device(UCLASS_RNG, 0, &dev));
+	ut_assertnonnull(dev);
+	dm_rng_read(dev, &val1, sizeof(val1));
+	dm_rng_read(dev, &val2, sizeof(val2));
+	ut_assert(val1 != val2);
+
+	return 0;
+}
+DM_TEST(dm_test_rng_read, DM_TESTF_SCAN_PDATA | DM_TESTF_SCAN_FDT);
-- 
2.7.4

[PATCH v2 3/7] stm32mp1: rng: Add a driver for random number generator(rng) device

[Patrice CHOTARD]

On 12/5/19 9:42 AM, Sughosh Ganu wrote:
> Add a driver for the rng device found on stm32mp1 platforms. The
> driver provides a routine for reading the random number seed from the
> hardware device.
>
> Signed-off-by: Sughosh Ganu <sughosh.ganu@linaro.org>
> ---
>
> Changes since V1:
> * Handle review comment from Patrice Chotard to remove the 'inited'
>   member
>
>  drivers/rng/Kconfig        |   7 ++
>  drivers/rng/Makefile       |   1 +
>  drivers/rng/stm32mp1_rng.c | 158 +++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 166 insertions(+)
>  create mode 100644 drivers/rng/stm32mp1_rng.c
>
> diff --git a/drivers/rng/Kconfig b/drivers/rng/Kconfig
> index dd44cc0..5fc11db 100644
> --- a/drivers/rng/Kconfig
> +++ b/drivers/rng/Kconfig
> @@ -5,3 +5,10 @@ config DM_RNG
>  	  Enable driver model for random number generator(rng) devices.
>  	  This interface is used to initialise the rng device and to
>  	  read the random seed from the device.
> +
> +config RNG_STM32MP1
> +       bool "Enable random number generator for STM32MP1"
> +       depends on ARCH_STM32MP && DM_RNG
> +       default n
> +       help
> +         Enable STM32MP1 rng driver.
> diff --git a/drivers/rng/Makefile b/drivers/rng/Makefile
> index 311705b..699beb3 100644
> --- a/drivers/rng/Makefile
> +++ b/drivers/rng/Makefile
> @@ -4,3 +4,4 @@
>  #
>  
>  obj-$(CONFIG_DM_RNG) += rng-uclass.o
> +obj-$(CONFIG_RNG_STM32MP1) += stm32mp1_rng.o
> diff --git a/drivers/rng/stm32mp1_rng.c b/drivers/rng/stm32mp1_rng.c
> new file mode 100644
> index 0000000..5cd736d
> --- /dev/null
> +++ b/drivers/rng/stm32mp1_rng.c
> @@ -0,0 +1,158 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * Copyright (c) 2019, Linaro Limited
> + */
> +
> +#include <common.h>
> +#include <clk.h>
> +#include <dm.h>
> +#include <reset.h>
> +#include <rng.h>
> +
> +#include <asm/io.h>
> +#include <linux/iopoll.h>
> +#include <linux/kernel.h>
> +
> +#define RNG_CR 0x00
> +#define RNG_CR_RNGEN BIT(2)
> +#define RNG_CR_CED BIT(5)
> +
> +#define RNG_SR 0x04
> +#define RNG_SR_SEIS BIT(6)
> +#define RNG_SR_CEIS BIT(5)
> +#define RNG_SR_SECS BIT(2)
> +#define RNG_SR_DRDY BIT(0)
> +
> +#define RNG_DR 0x08
> +
> +struct stm32_rng_platdata {
> +	fdt_addr_t base;
> +	struct clk clk;
> +	struct reset_ctl rst;
> +};
> +
> +static int stm32_rng_read(struct udevice *dev, void *data, size_t len)
> +{
> +	int retval = 0, i;
> +	u32 sr, count, reg;
> +	size_t increment;
> +	struct stm32_rng_platdata *pdata = dev_get_platdata(dev);
> +
> +	while (len > 0) {
> +		retval = readl_poll_timeout(pdata->base + RNG_SR, sr,
> +					    sr & RNG_SR_DRDY, 10000);
> +		if (retval)
> +			return retval;
> +
> +		if (sr & (RNG_SR_SEIS | RNG_SR_SECS)) {
> +			/* As per SoC TRM */
> +			clrbits_le32(pdata->base + RNG_SR, RNG_SR_SEIS);
> +			for (i = 0; i < 12; i++)
> +				readl(pdata->base + RNG_DR);
> +			if (readl(pdata->base + RNG_SR) & RNG_SR_SEIS) {
> +				printf("RNG Noise");
> +				return -EIO;
> +			}
> +			/* start again */
> +			continue;
> +		}
> +
> +		count = 4;
> +		while (len && count) {
> +			reg = readl(pdata->base + RNG_DR);
> +			memcpy(data, &reg, min(len, sizeof(u32)));
> +			increment = min(len, sizeof(u32));
> +			data += increment;
> +			retval += increment;
> +			len -= increment;
> +			count--;
> +		}
> +	}
> +
> +	return retval;
> +}
> +
> +static int stm32_rng_init(struct stm32_rng_platdata *pdata)
> +{
> +	int err;
> +
> +	err = clk_enable(&pdata->clk);
> +	if (err)
> +		return err;
> +
> +	/* Disable CED */
> +	writel(RNG_CR_RNGEN | RNG_CR_CED, pdata->base + RNG_CR);
> +
> +	/* clear error indicators */
> +	writel(0, pdata->base + RNG_SR);
> +
> +	return 0;
> +}
> +
> +static int stm32_rng_cleanup(struct stm32_rng_platdata *pdata)
> +{
> +
> +	writel(0, pdata->base + RNG_CR);
> +
> +	return clk_disable(&pdata->clk);
> +}
> +
> +static int stm32_rng_probe(struct udevice *dev)
> +{
> +	struct stm32_rng_platdata *pdata = dev_get_platdata(dev);
> +
> +	reset_assert(&pdata->rst);
> +	udelay(20);
> +	reset_deassert(&pdata->rst);
> +
> +	return stm32_rng_init(pdata);
> +}
> +
> +static int stm32_rng_remove(struct udevice *dev)
> +{
> +	struct stm32_rng_platdata *pdata = dev_get_platdata(dev);
> +
> +	return stm32_rng_cleanup(pdata);
> +}
> +
> +static int stm32_rng_ofdata_to_platdata(struct udevice *dev)
> +{
> +	struct stm32_rng_platdata *pdata = dev_get_platdata(dev);
> +	int err;
> +
> +	pdata->base = dev_read_addr(dev);
> +	if (!pdata->base)
> +		return -ENOMEM;
> +
> +	err = clk_get_by_index(dev, 0, &pdata->clk);
> +	if (err)
> +		return err;
> +
> +	err = reset_get_by_index(dev, 0, &pdata->rst);
> +	if (err)
> +		return err;
> +
> +	return 0;
> +}
> +
> +static const struct dm_rng_ops stm32_rng_ops = {
> +	.read = stm32_rng_read,
> +};
> +
> +static const struct udevice_id stm32_rng_match[] = {
> +	{
> +		.compatible = "st,stm32-rng",
> +	},
> +	{},
> +};
> +
> +U_BOOT_DRIVER(stm32_rng) = {
> +	.name = "stm32-rng",
> +	.id = UCLASS_RNG,
> +	.of_match = stm32_rng_match,
> +	.ops = &stm32_rng_ops,
> +	.probe = stm32_rng_probe,
> +	.remove = stm32_rng_remove,
> +	.platdata_auto_alloc_size = sizeof(struct stm32_rng_platdata),
> +	.ofdata_to_platdata = stm32_rng_ofdata_to_platdata,
> +};

Reviewed-by: Patrice Chotard <patrice.chotard@st.com>

Thanks