[PATCH v7 0/8] Add a random number generator uclass

[PATCH v7 0/8] 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 and qemu platforms. A dummy rng driver for sandbox has also
been added, along with the unit test for the rng uclass.

Changes since V6:
* Handle review comments from Heinrich Schuchardt to handle the
  scenario of data buffer being passed to the virtio rng driver not
  being aligned on 4 bytes.
* Handle review comment by Simon Glass to only keep a forward
  declaration of struct udevice in rng.h.

Changes since V5:
* Handle review comments from Heinrich Schuchardt to read all the
  bytes requested in the individual drivers.

Changes since V4:
* Get the read functions of individual drivers to return number of
  bytes read on successful read, and a -ve value on error.
* Handle review comments from Heinrich Schuchardt.

Changes since V3:
* Handle review comments from Patrick Delaunay

Changes since V2:
* Add a driver for the virtio-rng device on qemu platform

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 (8):
  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
  virtio: rng: Add a random number generator(rng) driver

 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                 |  22 +++++
 drivers/rng/Makefile                |   8 ++
 drivers/rng/rng-uclass.c            |  23 ++++++
 drivers/rng/sandbox_rng.c           |  56 +++++++++++++
 drivers/rng/stm32mp1_rng.c          | 161 ++++++++++++++++++++++++++++++++++++
 drivers/virtio/Kconfig              |   6 ++
 drivers/virtio/Makefile             |   1 +
 drivers/virtio/virtio-uclass.c      |   1 +
 drivers/virtio/virtio_rng.c         |  92 +++++++++++++++++++++
 include/dm/uclass-id.h              |   1 +
 include/rng.h                       |  33 ++++++++
 include/virtio.h                    |   4 +-
 test/dm/Makefile                    |   1 +
 test/dm/rng.c                       |  26 ++++++
 23 files changed, 452 insertions(+), 1 deletion(-)
 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 drivers/virtio/virtio_rng.c
 create mode 100644 include/rng.h
 create mode 100644 test/dm/rng.c

-- 
2.7.4

[PATCH v7 1/8] 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>
Reviewed-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Reviewed-by: Simon Glass <sjg@chromium.org>
---
Changes since V6:
* Handle review comment from Simon Glass to declare struct udevice in
  rng.h instead of including dm.h

 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            | 33 +++++++++++++++++++++++++++++++++
 7 files changed, 73 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 e977f19..6c619b1 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -115,4 +115,5 @@ 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..d2c0f9a
--- /dev/null
+++ b/include/rng.h
@@ -0,0 +1,33 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (c) 2019, Linaro Limited
+ */
+
+#if !defined _RNG_H_
+#define _RNG_H_
+
+struct udevice;
+
+/**
+ * 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
+ *
+ * Return: 0 if OK, -ve on error
+ */
+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
+	 *
+	 * Return: 0 if OK, -ve on error
+	 */
+	int (*read)(struct udevice *dev, void *data, size_t max);
+};
+
+#endif /* _RNG_H_ */
-- 
2.7.4

[PATCH v7 2/8] 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>
Acked-by: Patrick Delaunay <patrick.delaunay@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 v7 3/8] 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>
Reviewed-by: Patrice Chotard <patrice.chotard@st.com>
Acked-by: Patrick Delaunay <patrick.delaunay@st.com>
---
 drivers/rng/Kconfig        |   7 ++
 drivers/rng/Makefile       |   1 +
 drivers/rng/stm32mp1_rng.c | 161 +++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 169 insertions(+)
 create mode 100644 drivers/rng/stm32mp1_rng.c

diff --git a/drivers/rng/Kconfig b/drivers/rng/Kconfig
index dd44cc0..c9c4751 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..ec6af7e
--- /dev/null
+++ b/drivers/rng/stm32mp1_rng.c
@@ -0,0 +1,161 @@
+// 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;
+		}
+
+		/*
+		 * Once the DRDY bit is set, the RNG_DR register can
+		 * be read four consecutive times.
+		 */
+		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;
+			len -= increment;
+			count--;
+		}
+	}
+
+	return 0;
+}
+
+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 v7 4/8] 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>
Acked-by: Patrick Delaunay <patrick.delaunay@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 713a7e6..c85369c 100644
--- a/configs/stm32mp15_basic_defconfig
+++ b/configs/stm32mp15_basic_defconfig
@@ -143,3 +143,5 @@ 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 f9161fd..c192d8d 100644
--- a/configs/stm32mp15_optee_defconfig
+++ b/configs/stm32mp15_optee_defconfig
@@ -127,3 +127,5 @@ 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 a5ea528..a846962 100644
--- a/configs/stm32mp15_trusted_defconfig
+++ b/configs/stm32mp15_trusted_defconfig
@@ -126,3 +126,5 @@ 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 v7 5/8] 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>
Reviewed-by: Simon Glass <sjg@chromium.org>
---
 arch/sandbox/dts/test.dts |  4 ++++
 drivers/rng/Kconfig       |  8 +++++++
 drivers/rng/Makefile      |  1 +
 drivers/rng/sandbox_rng.c | 56 +++++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 69 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..fe1d14a 100644
--- a/arch/sandbox/dts/test.dts
+++ b/arch/sandbox/dts/test.dts
@@ -599,6 +599,10 @@
 		reset-names = "other", "test";
 	};
 
+	rng {
+		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 c9c4751..35a3bd1 100644
--- 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 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..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,
+};
-- 
2.7.4

[PATCH v7 6/8] 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>
Reviewed-by: Patrick Delaunay <patrick.delaunay@st.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
---
 configs/sandbox64_defconfig | 2 ++
 configs/sandbox_defconfig   | 2 ++
 2 files changed, 4 insertions(+)

diff --git a/configs/sandbox64_defconfig b/configs/sandbox64_defconfig
index cc536ff..a21d832 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 64245f7..9bdc0f5 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 v7 7/8] 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>
Reviewed-by: Simon Glass <sjg@chromium.org>
---
 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..ce20e2d
--- /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 rand1 = 0, rand2 = 0;
+	struct udevice *dev;
+
+	ut_assertok(uclass_get_device(UCLASS_RNG, 0, &dev));
+	ut_assertnonnull(dev);
+	ut_assertok(dm_rng_read(dev, &rand1, sizeof(rand1)));
+	ut_assertok(dm_rng_read(dev, &rand2, sizeof(rand2)));
+	ut_assert(rand1 != rand2);
+
+	return 0;
+}
+DM_TEST(dm_test_rng_read, DM_TESTF_SCAN_PDATA | DM_TESTF_SCAN_FDT);
-- 
2.7.4

[PATCH v7 8/8] virtio: rng: Add a random number generator(rng) driver

[Sughosh Ganu]

Add a driver for the virtio-rng device on the qemu platform. The
device uses pci as a transport medium. The driver can be enabled with
the following configs

CONFIG_VIRTIO
CONFIG_DM_RNG
CONFIG_VIRTIO_PCI
CONFIG_VIRTIO_RNG

Signed-off-by: Sughosh Ganu <sughosh.ganu@linaro.org>
---
Changes since V6:
* Handle review comments from Heinrich Schuchardt to handle the
  scenario of data buffer being passed to the virtio rng driver not
  being aligned on 4 bytes.

 drivers/virtio/Kconfig         |  6 +++
 drivers/virtio/Makefile        |  1 +
 drivers/virtio/virtio-uclass.c |  1 +
 drivers/virtio/virtio_rng.c    | 92 ++++++++++++++++++++++++++++++++++++++++++
 include/virtio.h               |  4 +-
 5 files changed, 103 insertions(+), 1 deletion(-)
 create mode 100644 drivers/virtio/virtio_rng.c

diff --git a/drivers/virtio/Kconfig b/drivers/virtio/Kconfig
index a9d5fd0..2e3dd3b 100644
--- a/drivers/virtio/Kconfig
+++ b/drivers/virtio/Kconfig
@@ -59,4 +59,10 @@ config VIRTIO_BLK
 	  This is the virtual block driver for virtio. It can be used with
 	  QEMU based targets.
 
+config VIRTIO_RNG
+       bool "virtio rng driver"
+       depends on VIRTIO
+       help
+         This is the virtual random number generator driver. It can be used
+	 with Qemu based targets.
 endmenu
diff --git a/drivers/virtio/Makefile b/drivers/virtio/Makefile
index 4579044..dc88809 100644
--- a/drivers/virtio/Makefile
+++ b/drivers/virtio/Makefile
@@ -9,3 +9,4 @@ obj-$(CONFIG_VIRTIO_PCI) += virtio_pci_legacy.o virtio_pci_modern.o
 obj-$(CONFIG_VIRTIO_SANDBOX) += virtio_sandbox.o
 obj-$(CONFIG_VIRTIO_NET) += virtio_net.o
 obj-$(CONFIG_VIRTIO_BLK) += virtio_blk.o
+obj-$(CONFIG_VIRTIO_RNG) += virtio_rng.o
diff --git a/drivers/virtio/virtio-uclass.c b/drivers/virtio/virtio-uclass.c
index 34397d7..436faa4 100644
--- a/drivers/virtio/virtio-uclass.c
+++ b/drivers/virtio/virtio-uclass.c
@@ -24,6 +24,7 @@
 static const char *const virtio_drv_name[VIRTIO_ID_MAX_NUM] = {
 	[VIRTIO_ID_NET]		= VIRTIO_NET_DRV_NAME,
 	[VIRTIO_ID_BLOCK]	= VIRTIO_BLK_DRV_NAME,
+	[VIRTIO_ID_RNG]		= VIRTIO_RNG_DRV_NAME,
 };
 
 int virtio_get_config(struct udevice *vdev, unsigned int offset,
diff --git a/drivers/virtio/virtio_rng.c b/drivers/virtio/virtio_rng.c
new file mode 100644
index 0000000..ffb6835
--- /dev/null
+++ b/drivers/virtio/virtio_rng.c
@@ -0,0 +1,92 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (c) 2019, Linaro Limited
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <rng.h>
+#include <virtio_types.h>
+#include <virtio.h>
+#include <virtio_ring.h>
+
+#define BUFFER_SIZE	16UL
+
+struct virtio_rng_priv {
+	struct virtqueue *rng_vq;
+};
+
+static int virtio_rng_read(struct udevice *dev, void *data, size_t len)
+{
+	int ret;
+	unsigned int rsize = 0;
+	size_t nbytes = len;
+	unsigned char buf[BUFFER_SIZE] __aligned(4);
+	unsigned char *ptr = data;
+	struct virtio_sg sg;
+	struct virtio_sg *sgs[1];
+	struct virtio_rng_priv *priv = dev_get_priv(dev);
+
+	if (!len)
+		return 0;
+
+	do {
+		sg.addr = buf;
+		sg.length = nbytes;
+		sgs[0] = &sg;
+
+		ret = virtqueue_add(priv->rng_vq, sgs, 0, 1);
+		if (ret)
+			return ret;
+
+		virtqueue_kick(priv->rng_vq);
+
+		while (!virtqueue_get_buf(priv->rng_vq, &rsize))
+			;
+
+		memcpy(ptr, buf, rsize);
+		nbytes -= rsize;
+		ptr += rsize;
+	} while (nbytes != 0);
+
+	return 0;
+}
+
+static int virtio_rng_bind(struct udevice *dev)
+{
+	struct virtio_dev_priv *uc_priv = dev_get_uclass_priv(dev->parent);
+
+	/* Indicate what driver features we support */
+	virtio_driver_features_init(uc_priv, NULL, 0, NULL, 0);
+
+	return 0;
+}
+
+static int virtio_rng_probe(struct udevice *dev)
+{
+	struct virtio_rng_priv *priv = dev_get_priv(dev);
+	int ret;
+
+	ret = virtio_find_vqs(dev, 1, &priv->rng_vq);
+	if (ret < 0) {
+		debug("%s: virtio_find_vqs failed\n", __func__);
+		return ret;
+	}
+
+	return 0;
+}
+
+static const struct dm_rng_ops virtio_rng_ops = {
+	.read	= virtio_rng_read,
+};
+
+U_BOOT_DRIVER(virtio_rng) = {
+	.name	= VIRTIO_RNG_DRV_NAME,
+	.id	= UCLASS_RNG,
+	.bind	= virtio_rng_bind,
+	.probe	= virtio_rng_probe,
+	.remove = virtio_reset,
+	.ops	= &virtio_rng_ops,
+	.priv_auto_alloc_size = sizeof(struct virtio_rng_priv),
+	.flags	= DM_FLAG_ACTIVE_DMA,
+};
diff --git a/include/virtio.h b/include/virtio.h
index 654fdf1..561dcc3 100644
--- a/include/virtio.h
+++ b/include/virtio.h
@@ -22,10 +22,12 @@
 
 #define VIRTIO_ID_NET		1 /* virtio net */
 #define VIRTIO_ID_BLOCK		2 /* virtio block */
-#define VIRTIO_ID_MAX_NUM	3
+#define VIRTIO_ID_RNG		4 /* virtio rng */
+#define VIRTIO_ID_MAX_NUM	5
 
 #define VIRTIO_NET_DRV_NAME	"virtio-net"
 #define VIRTIO_BLK_DRV_NAME	"virtio-blk"
+#define VIRTIO_RNG_DRV_NAME	"virtio-rng"
 
 /* Status byte for guest to report progress, and synchronize features */
 
-- 
2.7.4

[PATCH v7 8/8] virtio: rng: Add a random number generator(rng) driver

[Heinrich Schuchardt]

On 12/28/19 7:28 PM, Sughosh Ganu wrote:
> Add a driver for the virtio-rng device on the qemu platform. The
> device uses pci as a transport medium. The driver can be enabled with
> the following configs
>
> CONFIG_VIRTIO
> CONFIG_DM_RNG
> CONFIG_VIRTIO_PCI
> CONFIG_VIRTIO_RNG
>
> Signed-off-by: Sughosh Ganu <sughosh.ganu@linaro.org>
> ---
> Changes since V6:
> * Handle review comments from Heinrich Schuchardt to handle the
>    scenario of data buffer being passed to the virtio rng driver not
>    being aligned on 4 bytes.
>
>   drivers/virtio/Kconfig         |  6 +++
>   drivers/virtio/Makefile        |  1 +
>   drivers/virtio/virtio-uclass.c |  1 +
>   drivers/virtio/virtio_rng.c    | 92 ++++++++++++++++++++++++++++++++++++++++++
>   include/virtio.h               |  4 +-
>   5 files changed, 103 insertions(+), 1 deletion(-)
>   create mode 100644 drivers/virtio/virtio_rng.c
>
> diff --git a/drivers/virtio/Kconfig b/drivers/virtio/Kconfig
> index a9d5fd0..2e3dd3b 100644
> --- a/drivers/virtio/Kconfig
> +++ b/drivers/virtio/Kconfig
> @@ -59,4 +59,10 @@ config VIRTIO_BLK
>   	  This is the virtual block driver for virtio. It can be used with
>   	  QEMU based targets.
>
> +config VIRTIO_RNG
> +       bool "virtio rng driver"
> +       depends on VIRTIO
> +       help
> +         This is the virtual random number generator driver. It can be used
> +	 with Qemu based targets.
>   endmenu
> diff --git a/drivers/virtio/Makefile b/drivers/virtio/Makefile
> index 4579044..dc88809 100644
> --- a/drivers/virtio/Makefile
> +++ b/drivers/virtio/Makefile
> @@ -9,3 +9,4 @@ obj-$(CONFIG_VIRTIO_PCI) += virtio_pci_legacy.o virtio_pci_modern.o
>   obj-$(CONFIG_VIRTIO_SANDBOX) += virtio_sandbox.o
>   obj-$(CONFIG_VIRTIO_NET) += virtio_net.o
>   obj-$(CONFIG_VIRTIO_BLK) += virtio_blk.o
> +obj-$(CONFIG_VIRTIO_RNG) += virtio_rng.o
> diff --git a/drivers/virtio/virtio-uclass.c b/drivers/virtio/virtio-uclass.c
> index 34397d7..436faa4 100644
> --- a/drivers/virtio/virtio-uclass.c
> +++ b/drivers/virtio/virtio-uclass.c
> @@ -24,6 +24,7 @@
>   static const char *const virtio_drv_name[VIRTIO_ID_MAX_NUM] = {
>   	[VIRTIO_ID_NET]		= VIRTIO_NET_DRV_NAME,
>   	[VIRTIO_ID_BLOCK]	= VIRTIO_BLK_DRV_NAME,
> +	[VIRTIO_ID_RNG]		= VIRTIO_RNG_DRV_NAME,
>   };
>
>   int virtio_get_config(struct udevice *vdev, unsigned int offset,
> diff --git a/drivers/virtio/virtio_rng.c b/drivers/virtio/virtio_rng.c
> new file mode 100644
> index 0000000..ffb6835
> --- /dev/null
> +++ b/drivers/virtio/virtio_rng.c
> @@ -0,0 +1,92 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Copyright (c) 2019, Linaro Limited
> + */
> +
> +#include <common.h>
> +#include <dm.h>
> +#include <rng.h>
> +#include <virtio_types.h>
> +#include <virtio.h>
> +#include <virtio_ring.h>
> +
> +#define BUFFER_SIZE	16UL
> +
> +struct virtio_rng_priv {
> +	struct virtqueue *rng_vq;
> +};
> +
> +static int virtio_rng_read(struct udevice *dev, void *data, size_t len)
> +{
> +	int ret;
> +	unsigned int rsize = 0;
> +	size_t nbytes = len;
> +	unsigned char buf[BUFFER_SIZE] __aligned(4);
> +	unsigned char *ptr = data;
> +	struct virtio_sg sg;
> +	struct virtio_sg *sgs[1];
> +	struct virtio_rng_priv *priv = dev_get_priv(dev);
> +
> +	if (!len)
> +		return 0;
> +
> +	do {

If you use

	while(nbytes) {

here you can go without the if above. This will save 4 bytes of code on
ARMv8. In U-Boot we have tight code size constraints.

> +		sg.addr = buf;
> +		sg.length = nbytes;

We must avoid buffer overruns for len > 16:

sg.length = min(nbytes, BUFFER_SIZE);

The other patches of the series look fine to me.

Best regards

Heinrich

> +		sgs[0] = &sg;
> +
> +		ret = virtqueue_add(priv->rng_vq, sgs, 0, 1);
> +		if (ret)
> +			return ret;
> +
> +		virtqueue_kick(priv->rng_vq);
> +
> +		while (!virtqueue_get_buf(priv->rng_vq, &rsize))
> +			;
> +
> +		memcpy(ptr, buf, rsize);
> +		nbytes -= rsize;
> +		ptr += rsize;
> +	} while (nbytes != 0);
> +
> +	return 0;
> +}
> +
> +static int virtio_rng_bind(struct udevice *dev)
> +{
> +	struct virtio_dev_priv *uc_priv = dev_get_uclass_priv(dev->parent);
> +
> +	/* Indicate what driver features we support */
> +	virtio_driver_features_init(uc_priv, NULL, 0, NULL, 0);
> +
> +	return 0;
> +}
> +
> +static int virtio_rng_probe(struct udevice *dev)
> +{
> +	struct virtio_rng_priv *priv = dev_get_priv(dev);
> +	int ret;
> +
> +	ret = virtio_find_vqs(dev, 1, &priv->rng_vq);
> +	if (ret < 0) {
> +		debug("%s: virtio_find_vqs failed\n", __func__);
> +		return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +static const struct dm_rng_ops virtio_rng_ops = {
> +	.read	= virtio_rng_read,
> +};
> +
> +U_BOOT_DRIVER(virtio_rng) = {
> +	.name	= VIRTIO_RNG_DRV_NAME,
> +	.id	= UCLASS_RNG,
> +	.bind	= virtio_rng_bind,
> +	.probe	= virtio_rng_probe,
> +	.remove = virtio_reset,
> +	.ops	= &virtio_rng_ops,
> +	.priv_auto_alloc_size = sizeof(struct virtio_rng_priv),
> +	.flags	= DM_FLAG_ACTIVE_DMA,
> +};
> diff --git a/include/virtio.h b/include/virtio.h
> index 654fdf1..561dcc3 100644
> --- a/include/virtio.h
> +++ b/include/virtio.h
> @@ -22,10 +22,12 @@
>
>   #define VIRTIO_ID_NET		1 /* virtio net */
>   #define VIRTIO_ID_BLOCK		2 /* virtio block */
> -#define VIRTIO_ID_MAX_NUM	3
> +#define VIRTIO_ID_RNG		4 /* virtio rng */
> +#define VIRTIO_ID_MAX_NUM	5
>
>   #define VIRTIO_NET_DRV_NAME	"virtio-net"
>   #define VIRTIO_BLK_DRV_NAME	"virtio-blk"
> +#define VIRTIO_RNG_DRV_NAME	"virtio-rng"
>
>   /* Status byte for guest to report progress, and synchronize features */
>
>

[PATCH v7 8/8] virtio: rng: Add a random number generator(rng) driver

[Sughosh Ganu]

On Sun, 29 Dec 2019 at 02:59, Heinrich Schuchardt <xypron.glpk@gmx.de>
wrote:

> On 12/28/19 7:28 PM, Sughosh Ganu wrote:
> > Add a driver for the virtio-rng device on the qemu platform. The
> > device uses pci as a transport medium. The driver can be enabled with
> > the following configs
> >
> > CONFIG_VIRTIO
> > CONFIG_DM_RNG
> > CONFIG_VIRTIO_PCI
> > CONFIG_VIRTIO_RNG
> >
> > Signed-off-by: Sughosh Ganu <sughosh.ganu@linaro.org>
> > ---
> > Changes since V6:
> > * Handle review comments from Heinrich Schuchardt to handle the
> >    scenario of data buffer being passed to the virtio rng driver not
> >    being aligned on 4 bytes.
> >
> >   drivers/virtio/Kconfig         |  6 +++
> >   drivers/virtio/Makefile        |  1 +
> >   drivers/virtio/virtio-uclass.c |  1 +
> >   drivers/virtio/virtio_rng.c    | 92
> ++++++++++++++++++++++++++++++++++++++++++
> >   include/virtio.h               |  4 +-
> >   5 files changed, 103 insertions(+), 1 deletion(-)
> >   create mode 100644 drivers/virtio/virtio_rng.c
>

<snip>


> > diff --git a/drivers/virtio/virtio_rng.c b/drivers/virtio/virtio_rng.c
> > new file mode 100644
> > index 0000000..ffb6835
> > --- /dev/null
> > +++ b/drivers/virtio/virtio_rng.c
> > @@ -0,0 +1,92 @@
> > +// SPDX-License-Identifier: GPL-2.0+
> > +/*
> > + * Copyright (c) 2019, Linaro Limited
> > + */
> > +
> > +#include <common.h>
> > +#include <dm.h>
> > +#include <rng.h>
> > +#include <virtio_types.h>
> > +#include <virtio.h>
> > +#include <virtio_ring.h>
> > +
> > +#define BUFFER_SIZE  16UL
> > +
> > +struct virtio_rng_priv {
> > +     struct virtqueue *rng_vq;
> > +};
> > +
> > +static int virtio_rng_read(struct udevice *dev, void *data, size_t len)
> > +{
> > +     int ret;
> > +     unsigned int rsize = 0;
> > +     size_t nbytes = len;
> > +     unsigned char buf[BUFFER_SIZE] __aligned(4);
> > +     unsigned char *ptr = data;
> > +     struct virtio_sg sg;
> > +     struct virtio_sg *sgs[1];
> > +     struct virtio_rng_priv *priv = dev_get_priv(dev);
> > +
> > +     if (!len)
> > +             return 0;
> > +
> > +     do {
>
> If you use
>
>         while(nbytes) {
>

Ok.


>
> here you can go without the if above. This will save 4 bytes of code on
> ARMv8. In U-Boot we have tight code size constraints.
>
> > +             sg.addr = buf;
> > +             sg.length = nbytes;
>
> We must avoid buffer overruns for len > 16:
>
> sg.length = min(nbytes, BUFFER_SIZE);
>

Oops. Forgot to take care of this. Will incorporate this in the next
version. Also, I had sent you a unicast a couple of days back asking for
the code in virtqueue_get_buf which requires a 4 byte alignment for the
data pointer. The virtio32_to_cpu calls in virtqueue_get_buf are being used
to reference 'id' and 'len' members of structs. I don't see the 'addr'
member being used in this function. But i do see the data pointer being
used in virtqueue_add function, which actually casts this to a u64 value.
Can you point me to the function which actually dereferences the data
pointer as a u32 pointer. Thanks a lot for your in depth review.

-sughosh