[PATCH v2 0/3] sandbox: add HWRNG driver for host /dev/random

[PATCH v2 0/3] sandbox: add HWRNG driver for host /dev/random

[Ahmad Fatoum]

This series is useful for testing/using barebox,state on sandbox and for
use of host entropy while generating passwords for the target system.
They are in the same series, because the first commit adds linux_open,
which the last depends on.

v1 -> v2:
  - split off example sandbox state device tree into seperate commit
  - renamed device tree example to end with -example.dts

Ahmad Fatoum (3):
  sandbox: hostfile: allow probing from device tree
  sandbox: dts: add example for barebox,hostfile backed state
  hwrng: add sandbox driver interface to host /dev/random

 arch/sandbox/board/Makefile                   |  1 +
 arch/sandbox/board/board.c                    |  7 +++
 arch/sandbox/board/dev-random.c               | 24 +++++++
 arch/sandbox/board/hostfile.c                 | 16 +++--
 arch/sandbox/dts/sandbox-state-example.dtsi   | 50 +++++++++++++++
 .../sandbox/mach-sandbox/include/mach/linux.h |  8 +++
 arch/sandbox/os/common.c                      |  5 ++
 drivers/hw_random/Kconfig                     |  8 +++
 drivers/hw_random/Makefile                    |  1 +
 drivers/hw_random/dev-random.c                | 63 +++++++++++++++++++
 10 files changed, 179 insertions(+), 4 deletions(-)
 create mode 100644 arch/sandbox/board/dev-random.c
 create mode 100644 arch/sandbox/dts/sandbox-state-example.dtsi
 create mode 100644 drivers/hw_random/dev-random.c

-- 
2.20.1


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[PATCH v2 1/3] sandbox: hostfile: allow probing from device tree

[Ahmad Fatoum]

When testing things like barebox state in sandbox, it's nice to be able
to refer to a partition on a hostfile by phandle. Support this by
checking for reading the barebox,filename property.

Signed-off-by: Ahmad Fatoum <ahmad@a3f.at>
---
 arch/sandbox/board/hostfile.c                  | 16 ++++++++++++----
 arch/sandbox/mach-sandbox/include/mach/linux.h |  1 +
 arch/sandbox/os/common.c                       |  5 +++++
 3 files changed, 18 insertions(+), 4 deletions(-)

diff --git a/arch/sandbox/board/hostfile.c b/arch/sandbox/board/hostfile.c
index 745f078d1a79..e5a7580d0792 100644
--- a/arch/sandbox/board/hostfile.c
+++ b/arch/sandbox/board/hostfile.c
@@ -84,15 +84,16 @@ static int hf_probe(struct device_d *dev)
 	if (!dev->device_node)
 		return -ENODEV;
 
-	err = of_property_read_u32(dev->device_node, "barebox,fd", &priv->fd);
-	if (err)
-		return err;
+	of_property_read_u32(dev->device_node, "barebox,fd", &priv->fd);
 
 	err = of_property_read_string(dev->device_node, "barebox,filename",
 				      &priv->filename);
 	if (err)
 		return err;
 
+	if (!priv->fd)
+		priv->fd = linux_open(priv->filename, true);
+
 	priv->cdev.name = dev->device_node->name;
 	priv->cdev.dev = dev;
 	priv->cdev.ops = &hf_fops;
@@ -101,7 +102,14 @@ static int hf_probe(struct device_d *dev)
 	dev->info = hf_info;
 	dev->priv = priv;
 
-	return devfs_create(&priv->cdev);
+	err = devfs_create(&priv->cdev);
+	if (err)
+		return err;
+
+	of_parse_partitions(&priv->cdev, dev->device_node);
+	of_partitions_register_fixup(&priv->cdev);
+
+	return 0;
 }
 
 static __maybe_unused struct of_device_id hostfile_dt_ids[] = {
diff --git a/arch/sandbox/mach-sandbox/include/mach/linux.h b/arch/sandbox/mach-sandbox/include/mach/linux.h
index 7d0ed55735e7..c344285473e6 100644
--- a/arch/sandbox/mach-sandbox/include/mach/linux.h
+++ b/arch/sandbox/mach-sandbox/include/mach/linux.h
@@ -10,6 +10,7 @@ struct fb_bitfield;
 int linux_register_device(const char *name, void *start, void *end);
 int tap_alloc(const char *dev);
 uint64_t linux_get_time(void);
+int linux_open(const char *filename, int readwrite);
 int linux_read(int fd, void *buf, size_t count);
 int linux_read_nonblock(int fd, void *buf, size_t count);
 ssize_t linux_write(int fd, const void *buf, size_t count);
diff --git a/arch/sandbox/os/common.c b/arch/sandbox/os/common.c
index a7ea8f2d3b18..86118822a177 100644
--- a/arch/sandbox/os/common.c
+++ b/arch/sandbox/os/common.c
@@ -121,6 +121,11 @@ void __attribute__((noreturn)) linux_exit(void)
 	exit(0);
 }
 
+int linux_open(const char *filename, int readwrite)
+{
+	return open(filename, readwrite ? O_RDWR : O_RDONLY);
+}
+
 int linux_read(int fd, void *buf, size_t count)
 {
 	ssize_t ret;
-- 
2.20.1


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[PATCH v2 2/3] sandbox: dts: add example for barebox, hostfile backed state

[Ahmad Fatoum]

Previous commit now allows probing barebox,hostfile to be probed from
device tree. Add a barebox state node that shows how to use it. It's not
included by default, same as barebox-libftdi-example.dtsi in the same
directory.

Signed-off-by: Ahmad Fatoum <ahmad@a3f.at>
---
 arch/sandbox/dts/sandbox-state-example.dtsi | 50 +++++++++++++++++++++
 1 file changed, 50 insertions(+)
 create mode 100644 arch/sandbox/dts/sandbox-state-example.dtsi

diff --git a/arch/sandbox/dts/sandbox-state-example.dtsi b/arch/sandbox/dts/sandbox-state-example.dtsi
new file mode 100644
index 000000000000..fc17bd078899
--- /dev/null
+++ b/arch/sandbox/dts/sandbox-state-example.dtsi
@@ -0,0 +1,50 @@
+/ {
+	aliases {
+		state = &state;
+	};
+
+	disk {
+		compatible = "barebox,hostfile";
+		barebox,filename = "disk";
+		reg = <0x0 0x0 0x100000>;
+
+		partitions {
+			compatible = "fixed-partitions";
+			#address-cells = <1>;
+			#size-cells = <1>;
+
+			hostfile_state: state@0 {
+				reg = <0x0 0x1000>;
+				label = "state";
+			};
+		};
+	};
+
+	state: state {
+		magic = <0xaa3b86a6>;
+		compatible = "barebox,state";
+		backend-type = "raw";
+		backend = <&hostfile_state>;
+		backend-storage-type = "direct";
+		backend-stridesize = <64>;
+
+		#address-cells = <1>;
+		#size-cells = <1>;
+		vars {
+			#address-cells = <1>;
+			#size-cells = <1>;
+
+			x {
+				reg = <0x0 0x4>;
+				type = "uint32";
+				default = <1>;
+			};
+
+			y {
+				reg = <0x4 0x4>;
+				type = "uint32";
+				default = <3>;
+			};
+		};
+	};
+};
-- 
2.20.1


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[PATCH v2 3/3] hwrng: add sandbox driver interface to host /dev/random

[Ahmad Fatoum]

Linux as well as other operating systems can provide /dev/random and
/dev/urandom device to service userspace need for randomness.
Add a driver to use /dev/random for blocking and /dev/urandom for
non-blocking barebox random numbers.

Signed-off-by: Ahmad Fatoum <ahmad@a3f.at>
---
 arch/sandbox/board/Makefile                   |  1 +
 arch/sandbox/board/board.c                    |  7 +++
 arch/sandbox/board/dev-random.c               | 24 +++++++
 .../sandbox/mach-sandbox/include/mach/linux.h |  7 +++
 drivers/hw_random/Kconfig                     |  8 +++
 drivers/hw_random/Makefile                    |  1 +
 drivers/hw_random/dev-random.c                | 63 +++++++++++++++++++
 7 files changed, 111 insertions(+)
 create mode 100644 arch/sandbox/board/dev-random.c
 create mode 100644 drivers/hw_random/dev-random.c

diff --git a/arch/sandbox/board/Makefile b/arch/sandbox/board/Makefile
index b6c271c858c6..26f6cb192269 100644
--- a/arch/sandbox/board/Makefile
+++ b/arch/sandbox/board/Makefile
@@ -5,5 +5,6 @@ obj-y += console.o
 obj-y += devices.o
 obj-y += dtb.o
 obj-y += poweroff.o
+obj-y += dev-random.o
 
 extra-y += barebox.lds
diff --git a/arch/sandbox/board/board.c b/arch/sandbox/board/board.c
index 1f6392d15ed3..ad2bc910c342 100644
--- a/arch/sandbox/board/board.c
+++ b/arch/sandbox/board/board.c
@@ -42,6 +42,11 @@ static struct device_d sdl_device = {
 	.platform_data = &mode,
 };
 
+static struct device_d devrandom_device = {
+	.id	  = DEVICE_ID_DYNAMIC,
+	.name     = "devrandom",
+};
+
 static int devices_init(void)
 {
 	platform_device_register(&tap_device);
@@ -54,6 +59,8 @@ static int devices_init(void)
 
 	platform_device_register(&sdl_device);
 
+	platform_device_register(&devrandom_device);
+
 	return 0;
 }
 
diff --git a/arch/sandbox/board/dev-random.c b/arch/sandbox/board/dev-random.c
new file mode 100644
index 000000000000..f65e5ef6e5ed
--- /dev/null
+++ b/arch/sandbox/board/dev-random.c
@@ -0,0 +1,24 @@
+#include <common.h>
+#include <mach/linux.h>
+
+devrandom_t *devrandom_init(void) {
+	devrandom_t *fds = xzalloc(sizeof(*fds));
+
+	fds->randomfd = linux_open("/dev/random", false);
+	if (fds->randomfd < 0)
+		return ERR_PTR(-EPERM);
+
+	fds->urandomfd = linux_open("/dev/urandom", false);
+	if (fds->urandomfd < 0)
+		return ERR_PTR(-EPERM);
+
+	return fds;
+}
+
+int devrandom_read(devrandom_t *devrandom, void *buf, size_t len, int wait)
+{
+	if (wait)
+		return linux_read(devrandom->randomfd, buf, len);
+
+	return linux_read(devrandom->urandomfd, buf, len);
+}
diff --git a/arch/sandbox/mach-sandbox/include/mach/linux.h b/arch/sandbox/mach-sandbox/include/mach/linux.h
index c344285473e6..1e64d41c6a5e 100644
--- a/arch/sandbox/mach-sandbox/include/mach/linux.h
+++ b/arch/sandbox/mach-sandbox/include/mach/linux.h
@@ -51,4 +51,11 @@ void barebox_libftdi1_gpio_set_value(struct ft2232_bitbang *ftbb,
 int barebox_libftdi1_update(struct ft2232_bitbang *ftbb);
 void barebox_libftdi1_close(void);
 
+typedef struct {
+	int randomfd;
+	int urandomfd;
+} devrandom_t;
+devrandom_t *devrandom_init(void);
+int devrandom_read(devrandom_t *devrandom, void *buf, size_t len, int wait);
+
 #endif /* __ASM_ARCH_LINUX_H */
diff --git a/drivers/hw_random/Kconfig b/drivers/hw_random/Kconfig
index d1297a48d0bb..c57928204d30 100644
--- a/drivers/hw_random/Kconfig
+++ b/drivers/hw_random/Kconfig
@@ -14,4 +14,12 @@ config HWRNG_MXC_RNGC
 	  This driver provides kernel-side support for the Random Number
 	  Generator hardware found on some Freescale i.MX processors.
 
+config HWRNG_DEV_RANDOM
+	tristate "Linux /dev/random and /dev/urandom RNG"
+	depends on SANDBOX
+	default y
+	help
+	  This driver allows use of the host provided /dev/random
+	  and /dev/urandom as barebox HWRNGs.
+
 endif
diff --git a/drivers/hw_random/Makefile b/drivers/hw_random/Makefile
index 79c238c48d60..8be62f38b740 100644
--- a/drivers/hw_random/Makefile
+++ b/drivers/hw_random/Makefile
@@ -1,2 +1,3 @@
 obj-$(CONFIG_HWRNG)		+= core.o
 obj-$(CONFIG_HWRNG_MXC_RNGC) += mxc-rngc.o
+obj-$(CONFIG_HWRNG_DEV_RANDOM) += dev-random.o
diff --git a/drivers/hw_random/dev-random.c b/drivers/hw_random/dev-random.c
new file mode 100644
index 000000000000..2170db7437ce
--- /dev/null
+++ b/drivers/hw_random/dev-random.c
@@ -0,0 +1,63 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019 Ahmad Fatoum, Pengutronix
+ */
+
+#include <common.h>
+#include <init.h>
+#include <linux/hw_random.h>
+#include <mach/linux.h>
+
+struct devrandom_rnd {
+	struct hwrng hwrng;
+	devrandom_t *priv;
+};
+
+static inline struct devrandom_rnd *to_rnd(struct hwrng *hwrng)
+{
+	return container_of(hwrng, struct devrandom_rnd, hwrng);
+}
+
+static int devrandom_rnd_read(struct hwrng *hwrng, void *buf, size_t max, bool wait)
+{
+	return devrandom_read(to_rnd(hwrng)->priv, buf, max, wait);
+}
+
+static int devrandom_rnd_init(struct hwrng *hwrng)
+{
+	devrandom_t *devrandom = devrandom_init();
+	if (IS_ERR(devrandom))
+		return PTR_ERR(devrandom);
+
+	to_rnd(hwrng)->priv = devrandom;
+	return 0;
+}
+
+static int devrandom_rnd_probe(struct device_d *dev)
+{
+	struct devrandom_rnd *rnd;
+	int ret;
+
+	rnd = xzalloc(sizeof(*rnd));
+
+	rnd->hwrng.name = dev->name;
+	rnd->hwrng.read = devrandom_rnd_read;
+	rnd->hwrng.init = devrandom_rnd_init;
+
+	ret = hwrng_register(dev, &rnd->hwrng);
+	if (ret) {
+		dev_err(dev, "failed to register: %s\n", strerror(-ret));
+
+		return ret;
+	}
+
+	dev_info(dev, "Registered.\n");
+
+	return 0;
+}
+
+static struct driver_d devrandom_rnd_driver = {
+	.name	= "devrandom",
+	.probe	= devrandom_rnd_probe,
+};
+device_platform_driver(devrandom_rnd_driver);
-- 
2.20.1


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Re: [PATCH v2 0/3] sandbox: add HWRNG driver for host /dev/random

[Sascha Hauer]

On Mon, Sep 09, 2019 at 11:31:27AM +0200, Ahmad Fatoum wrote:
> This series is useful for testing/using barebox,state on sandbox and for
> use of host entropy while generating passwords for the target system.
> They are in the same series, because the first commit adds linux_open,
> which the last depends on.
> 
> v1 -> v2:
>   - split off example sandbox state device tree into seperate commit
>   - renamed device tree example to end with -example.dts
> 
> Ahmad Fatoum (3):
>   sandbox: hostfile: allow probing from device tree
>   sandbox: dts: add example for barebox,hostfile backed state
>   hwrng: add sandbox driver interface to host /dev/random

Applied, thanks

Sascha


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