Hello Andy, Hans, Ilpo, Arnd, Gregory, and others,
this is v9 of the series adding Turris Omnia MCU driver.
This series still depends on the immutable branch between LEDs and
locking, introducing devm_mutex_init(), see the PR
https://lore.kernel.org/linux-leds/[email protected]/
See also cover letters for v1, v2, v3, v4, v5, v6, v7 and v8:
https://patchwork.kernel.org/project/linux-soc/cover/[email protected]/
https://patchwork.kernel.org/project/linux-soc/cover/[email protected]/
https://patchwork.kernel.org/project/linux-soc/cover/[email protected]/
https://patchwork.kernel.org/project/linux-soc/cover/[email protected]/
https://patchwork.kernel.org/project/linux-soc/cover/[email protected]/
https://patchwork.kernel.org/project/linux-soc/cover/[email protected]/
https://patchwork.kernel.org/project/linux-soc/cover/[email protected]/
https://patchwork.kernel.org/project/linux-soc/cover/[email protected]/
Changes since v8:
- removed the MACH_ARMADA_38X || COMPILE_TEST dependency for the
CZNIC_PLATFORMS Kconfig option in the Kconfig file, as suggested
by Andy (patch 2)
- fixed the issues in the global header turris-omnia-mcu-interface.h
pointed out by Andy and Ilpo: added the "OMNIA_" prefix to all
enumerator entries, added trailing commas, converted to use
FIELD_PREP_CONST() (patches 2-7)
- added comment why we can't use ether_addr_copy(), as requested by
Andy (patch 2)
- rewritten the error message for when the MCU does not support
reporting features, requested by Andy (patch 2)
- changed how the nul-byte is assigned to the end of bin2hex() result,
requested by Andy (patch 2)
- made the omnia_cmd_write_read() function final in patch 2, instead of
updating it in subsequent patches, requested by Andy
- in order to be more consistent, changed the omnia_cmd_read_u8() and
omnia_cmd_read_u16() functions to return zero on success and the read
value is passed into a pointer, and then added a new function
omnia_cmd_read_u32(), as requested by Ilpo (he did not like the
inconsistency in omnia_mcu_read_features(), where the
omnia_cmd_read_u16() hid the le16_to_cpu() call, but then we did an
explicit call to le32_to_cpu() when reading 32-bit features) (patch 2)
- some other minor tweaks (changed the version type from u8[] to char[],
changed len type from size_t to unsigned int in omnia_cmd_write())
(patches 2 & 3)
- dropped the "gpio%u." prefix from GPIO line names, Andy pointed out
why this is wrong (patch 3)
- decoupled GPIOs information struct definition and assignment and put
filling macros before the assignment, requested by Andy (patch 3)
- moved return value check into the guarded scope, suggested by Andy
(patch 3)
- put some assignments into the definition lines, suggested by Andy
(patch 3)
- fixed some typos (patches 2 & 3)
- refactored the reply length computation into a new function
omnia_compute_reply_length(), as requested by Andy (patch 3)
Marek Behún (9):
dt-bindings: firmware: add cznic,turris-omnia-mcu binding
platform: cznic: Add preliminary support for Turris Omnia MCU
platform: cznic: turris-omnia-mcu: Add support for MCU connected GPIOs
platform: cznic: turris-omnia-mcu: Add support for poweroff and wakeup
platform: cznic: turris-omnia-mcu: Add support for MCU watchdog
platform: cznic: turris-omnia-mcu: Add support for MCU provided TRNG
platform: cznic: turris-omnia-mcu: Add support for digital message
signing via debugfs
ARM: dts: turris-omnia: Add MCU system-controller node
ARM: dts: turris-omnia: Add GPIO key node for front button
.../ABI/testing/debugfs-turris-omnia-mcu | 13 +
.../sysfs-bus-i2c-devices-turris-omnia-mcu | 126 ++
.../firmware/cznic,turris-omnia-mcu.yaml | 86 ++
MAINTAINERS | 5 +
.../dts/marvell/armada-385-turris-omnia.dts | 35 +-
drivers/platform/Kconfig | 2 +
drivers/platform/Makefile | 1 +
drivers/platform/cznic/Kconfig | 50 +
drivers/platform/cznic/Makefile | 9 +
.../platform/cznic/turris-omnia-mcu-base.c | 451 +++++++
.../platform/cznic/turris-omnia-mcu-debugfs.c | 207 ++++
.../platform/cznic/turris-omnia-mcu-gpio.c | 1040 +++++++++++++++++
.../cznic/turris-omnia-mcu-sys-off-wakeup.c | 258 ++++
.../platform/cznic/turris-omnia-mcu-trng.c | 103 ++
.../cznic/turris-omnia-mcu-watchdog.c | 127 ++
drivers/platform/cznic/turris-omnia-mcu.h | 210 ++++
include/linux/turris-omnia-mcu-interface.h | 249 ++++
17 files changed, 2971 insertions(+), 1 deletion(-)
create mode 100644 Documentation/ABI/testing/debugfs-turris-omnia-mcu
create mode 100644 Documentation/ABI/testing/sysfs-bus-i2c-devices-turris-omnia-mcu
create mode 100644 Documentation/devicetree/bindings/firmware/cznic,turris-omnia-mcu.yaml
create mode 100644 drivers/platform/cznic/Kconfig
create mode 100644 drivers/platform/cznic/Makefile
create mode 100644 drivers/platform/cznic/turris-omnia-mcu-base.c
create mode 100644 drivers/platform/cznic/turris-omnia-mcu-debugfs.c
create mode 100644 drivers/platform/cznic/turris-omnia-mcu-gpio.c
create mode 100644 drivers/platform/cznic/turris-omnia-mcu-sys-off-wakeup.c
create mode 100644 drivers/platform/cznic/turris-omnia-mcu-trng.c
create mode 100644 drivers/platform/cznic/turris-omnia-mcu-watchdog.c
create mode 100644 drivers/platform/cznic/turris-omnia-mcu.h
create mode 100644 include/linux/turris-omnia-mcu-interface.h
--
2.43.2
Add support for true random number generator provided by the MCU.
New Omnia boards come without the Atmel SHA204-A chip. Instead the
crypto functionality is provided by new microcontroller, which has
a TRNG peripheral.
Signed-off-by: Marek Behún <[email protected]>
---
drivers/platform/cznic/Kconfig | 2 +
drivers/platform/cznic/Makefile | 1 +
.../platform/cznic/turris-omnia-mcu-base.c | 6 +-
.../platform/cznic/turris-omnia-mcu-gpio.c | 2 +-
.../platform/cznic/turris-omnia-mcu-trng.c | 103 ++++++++++++++++++
drivers/platform/cznic/turris-omnia-mcu.h | 8 ++
6 files changed, 120 insertions(+), 2 deletions(-)
create mode 100644 drivers/platform/cznic/turris-omnia-mcu-trng.c
diff --git a/drivers/platform/cznic/Kconfig b/drivers/platform/cznic/Kconfig
index e262930b3faf..6edac80d5fa3 100644
--- a/drivers/platform/cznic/Kconfig
+++ b/drivers/platform/cznic/Kconfig
@@ -18,6 +18,7 @@ config TURRIS_OMNIA_MCU
depends on I2C
select GPIOLIB
select GPIOLIB_IRQCHIP
+ select HW_RANDOM
select RTC_CLASS
select WATCHDOG_CORE
help
@@ -27,6 +28,7 @@ config TURRIS_OMNIA_MCU
- board poweroff into true low power mode (with voltage regulators
disabled) and the ability to configure wake up from this mode (via
rtcwake)
+ - true random number generator (if available on the MCU)
- MCU watchdog
- GPIO pins
- to get front button press events (the front button can be
diff --git a/drivers/platform/cznic/Makefile b/drivers/platform/cznic/Makefile
index 687f7718c0a1..eae4c6b341ff 100644
--- a/drivers/platform/cznic/Makefile
+++ b/drivers/platform/cznic/Makefile
@@ -4,4 +4,5 @@ obj-$(CONFIG_TURRIS_OMNIA_MCU) += turris-omnia-mcu.o
turris-omnia-mcu-y := turris-omnia-mcu-base.o
turris-omnia-mcu-y += turris-omnia-mcu-gpio.o
turris-omnia-mcu-y += turris-omnia-mcu-sys-off-wakeup.o
+turris-omnia-mcu-y += turris-omnia-mcu-trng.o
turris-omnia-mcu-y += turris-omnia-mcu-watchdog.o
diff --git a/drivers/platform/cznic/turris-omnia-mcu-base.c b/drivers/platform/cznic/turris-omnia-mcu-base.c
index cf37c3a70497..70ae5687ab4c 100644
--- a/drivers/platform/cznic/turris-omnia-mcu-base.c
+++ b/drivers/platform/cznic/turris-omnia-mcu-base.c
@@ -381,7 +381,11 @@ static int omnia_mcu_probe(struct i2c_client *client)
if (err)
return err;
- return omnia_mcu_register_gpiochip(mcu);
+ err = omnia_mcu_register_gpiochip(mcu);
+ if (err)
+ return err;
+
+ return omnia_mcu_register_trng(mcu);
}
static const struct of_device_id of_omnia_mcu_match[] = {
diff --git a/drivers/platform/cznic/turris-omnia-mcu-gpio.c b/drivers/platform/cznic/turris-omnia-mcu-gpio.c
index 438c8e909c5c..f1a931d6b16b 100644
--- a/drivers/platform/cznic/turris-omnia-mcu-gpio.c
+++ b/drivers/platform/cznic/turris-omnia-mcu-gpio.c
@@ -167,7 +167,7 @@ static const struct omnia_gpio omnia_gpios[64] = {
};
/* mapping from interrupts to indexes of GPIOs in the omnia_gpios array */
-static const u8 omnia_int_to_gpio_idx[32] = {
+const u8 omnia_int_to_gpio_idx[32] = {
[__bf_shf(OMNIA_INT_CARD_DET)] = 4,
[__bf_shf(OMNIA_INT_MSATA_IND)] = 5,
[__bf_shf(OMNIA_INT_USB30_OVC)] = 6,
diff --git a/drivers/platform/cznic/turris-omnia-mcu-trng.c b/drivers/platform/cznic/turris-omnia-mcu-trng.c
new file mode 100644
index 000000000000..d59ef7b51b02
--- /dev/null
+++ b/drivers/platform/cznic/turris-omnia-mcu-trng.c
@@ -0,0 +1,103 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * CZ.NIC's Turris Omnia MCU TRNG driver
+ *
+ * 2024 by Marek Behún <[email protected]>
+ */
+
+#include <linux/bitfield.h>
+#include <linux/completion.h>
+#include <linux/gpio/consumer.h>
+#include <linux/gpio/driver.h>
+#include <linux/hw_random.h>
+#include <linux/i2c.h>
+#include <linux/interrupt.h>
+#include <linux/minmax.h>
+#include <linux/module.h>
+#include <linux/string.h>
+#include <linux/turris-omnia-mcu-interface.h>
+#include <linux/types.h>
+
+#include "turris-omnia-mcu.h"
+
+#define OMNIA_CMD_TRNG_MAX_ENTROPY_LEN 64
+
+static irqreturn_t omnia_trng_irq_handler(int irq, void *dev_id)
+{
+ struct omnia_mcu *mcu = dev_id;
+
+ complete(&mcu->trng_completion);
+
+ return IRQ_HANDLED;
+}
+
+static int omnia_trng_read(struct hwrng *rng, void *data, size_t max, bool wait)
+{
+ struct omnia_mcu *mcu = (struct omnia_mcu *)rng->priv;
+ u8 reply[1 + OMNIA_CMD_TRNG_MAX_ENTROPY_LEN];
+ int err, bytes;
+
+ if (!wait && !completion_done(&mcu->trng_completion))
+ return 0;
+
+ do {
+ if (wait_for_completion_interruptible(&mcu->trng_completion))
+ return -EINTR;
+
+ err = omnia_cmd_read(mcu->client,
+ OMNIA_CMD_TRNG_COLLECT_ENTROPY,
+ reply, sizeof(reply));
+ if (err)
+ return err;
+
+ bytes = min3(reply[0], max, OMNIA_CMD_TRNG_MAX_ENTROPY_LEN);
+ } while (wait && !bytes);
+
+ memcpy(data, &reply[1], bytes);
+
+ return bytes;
+}
+
+int omnia_mcu_register_trng(struct omnia_mcu *mcu)
+{
+ struct device *dev = &mcu->client->dev;
+ u8 irq_idx, dummy;
+ int irq, err;
+
+ if (!(mcu->features & OMNIA_FEAT_TRNG))
+ return 0;
+
+ irq_idx = omnia_int_to_gpio_idx[__bf_shf(OMNIA_INT_TRNG)];
+ irq = gpiod_to_irq(gpiochip_get_desc(&mcu->gc, irq_idx));
+ if (irq < 0)
+ return dev_err_probe(dev, irq, "Cannot get TRNG IRQ\n");
+
+ /*
+ * If someone else cleared the TRNG interrupt but did not read the
+ * entropy, a new interrupt won't be generated, and entropy collection
+ * will be stuck. Ensure an interrupt will be generated by executing
+ * the collect entropy command (and discarding the result).
+ */
+ err = omnia_cmd_read(mcu->client, OMNIA_CMD_TRNG_COLLECT_ENTROPY,
+ &dummy, 1);
+ if (err)
+ return err;
+
+ init_completion(&mcu->trng_completion);
+
+ err = devm_request_threaded_irq(dev, irq, NULL, omnia_trng_irq_handler,
+ IRQF_ONESHOT, "turris-omnia-mcu-trng",
+ mcu);
+ if (err)
+ return dev_err_probe(dev, err, "Cannot request TRNG IRQ\n");
+
+ mcu->trng.name = "turris-omnia-mcu-trng";
+ mcu->trng.read = omnia_trng_read;
+ mcu->trng.priv = (unsigned long)mcu;
+
+ err = devm_hwrng_register(dev, &mcu->trng);
+ if (err)
+ return dev_err_probe(dev, err, "Cannot register TRNG\n");
+
+ return 0;
+}
diff --git a/drivers/platform/cznic/turris-omnia-mcu.h b/drivers/platform/cznic/turris-omnia-mcu.h
index a5a0b55b56d4..ef0b7dd6e485 100644
--- a/drivers/platform/cznic/turris-omnia-mcu.h
+++ b/drivers/platform/cznic/turris-omnia-mcu.h
@@ -9,7 +9,9 @@
#define __TURRIS_OMNIA_MCU_H
#include <linux/bitops.h>
+#include <linux/completion.h>
#include <linux/gpio/driver.h>
+#include <linux/hw_random.h>
#include <linux/if_ether.h>
#include <linux/mutex.h>
#include <linux/rtc.h>
@@ -47,6 +49,10 @@ struct omnia_mcu {
/* MCU watchdog */
struct watchdog_device wdt;
+
+ /* true random number generator */
+ struct hwrng trng;
+ struct completion trng_completion;
};
int omnia_cmd_write_read(const struct i2c_client *client,
@@ -169,11 +175,13 @@ static inline int omnia_cmd_read_u8(const struct i2c_client *client, u8 cmd,
return omnia_cmd_read(client, cmd, reply, sizeof(*reply));
}
+extern const u8 omnia_int_to_gpio_idx[32];
extern const struct attribute_group omnia_mcu_gpio_group;
extern const struct attribute_group omnia_mcu_poweroff_group;
int omnia_mcu_register_gpiochip(struct omnia_mcu *mcu);
int omnia_mcu_register_sys_off_and_wakeup(struct omnia_mcu *mcu);
+int omnia_mcu_register_trng(struct omnia_mcu *mcu);
int omnia_mcu_register_watchdog(struct omnia_mcu *mcu);
#endif /* __TURRIS_OMNIA_MCU_H */
--
2.43.2
Add support for digital message signing with private key stored in the
MCU. Boards with MKL MCUs have a NIST256p ECDSA private key created
when manufactured. The private key is not readable from the MCU, but
MCU allows for signing messages with it and retrieving the public key.
As described in a similar commit 50524d787de3 ("firmware:
turris-mox-rwtm: support ECDSA signatures via debugfs"):
The optimal solution would be to register an akcipher provider via
kernel's crypto API, but crypto API does not yet support accessing
akcipher API from userspace (and probably won't for some time, see
https://www.spinics.net/lists/linux-crypto/msg38388.html).
Therefore we add support for accessing this signature generation
mechanism via debugfs for now, so that userspace can access it.
Signed-off-by: Marek Behún <[email protected]>
---
.../ABI/testing/debugfs-turris-omnia-mcu | 13 ++
.../sysfs-bus-i2c-devices-turris-omnia-mcu | 13 ++
MAINTAINERS | 1 +
drivers/platform/cznic/Kconfig | 2 +
drivers/platform/cznic/Makefile | 1 +
.../platform/cznic/turris-omnia-mcu-base.c | 45 +++-
.../platform/cznic/turris-omnia-mcu-debugfs.c | 207 ++++++++++++++++++
drivers/platform/cznic/turris-omnia-mcu.h | 23 ++
8 files changed, 304 insertions(+), 1 deletion(-)
create mode 100644 Documentation/ABI/testing/debugfs-turris-omnia-mcu
create mode 100644 drivers/platform/cznic/turris-omnia-mcu-debugfs.c
diff --git a/Documentation/ABI/testing/debugfs-turris-omnia-mcu b/Documentation/ABI/testing/debugfs-turris-omnia-mcu
new file mode 100644
index 000000000000..1665005c2dcd
--- /dev/null
+++ b/Documentation/ABI/testing/debugfs-turris-omnia-mcu
@@ -0,0 +1,13 @@
+What: /sys/kernel/debug/turris-omnia-mcu/do_sign
+Date: July 2024
+KernelVersion: 6.10
+Contact: Marek Behún <[email protected]>
+Description:
+
+ ======= ===========================================================
+ (Write) Message to sign with the ECDSA private key stored in MCU.
+ The message must be exactly 32 bytes long (since this is
+ intended to be a SHA-256 hash).
+ (Read) The resulting signature, 64 bytes. This contains the R and
+ S values of the ECDSA signature, both in big-endian format.
+ ======= ===========================================================
diff --git a/Documentation/ABI/testing/sysfs-bus-i2c-devices-turris-omnia-mcu b/Documentation/ABI/testing/sysfs-bus-i2c-devices-turris-omnia-mcu
index 5e2d8ec52374..42710b8c77ef 100644
--- a/Documentation/ABI/testing/sysfs-bus-i2c-devices-turris-omnia-mcu
+++ b/Documentation/ABI/testing/sysfs-bus-i2c-devices-turris-omnia-mcu
@@ -90,6 +90,19 @@ Description: (RO) Contains the microcontroller type (STM32, GD32, MKL).
Format: %s.
+What: /sys/bus/i2c/devices/<mcu_device>/public_key
+Date: July 2024
+KernelVersion: 6.10
+Contact: Marek Behún <[email protected]>
+Description: (RO) Contains board ECDSA public key.
+
+ Only available if MCU supports signing messages with the ECDSA
+ algorithm. If so, the board has a private key stored in the MCU
+ that was generated during manufacture and cannot be retrieved
+ from the MCU.
+
+ Format: %s.
+
What: /sys/bus/i2c/devices/<mcu_device>/reset_selector
Date: July 2024
KernelVersion: 6.10
diff --git a/MAINTAINERS b/MAINTAINERS
index b27cc5feb64f..11c93b6029f4 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -2139,6 +2139,7 @@ M: Marek Behún <[email protected]>
S: Maintained
W: https://www.turris.cz/
F: Documentation/ABI/testing/debugfs-moxtet
+F: Documentation/ABI/testing/debugfs-turris-omnia-mcu
F: Documentation/ABI/testing/sysfs-bus-i2c-devices-turris-omnia-mcu
F: Documentation/ABI/testing/sysfs-bus-moxtet-devices
F: Documentation/ABI/testing/sysfs-firmware-turris-mox-rwtm
diff --git a/drivers/platform/cznic/Kconfig b/drivers/platform/cznic/Kconfig
index 6edac80d5fa3..152c866d63a6 100644
--- a/drivers/platform/cznic/Kconfig
+++ b/drivers/platform/cznic/Kconfig
@@ -29,6 +29,8 @@ config TURRIS_OMNIA_MCU
disabled) and the ability to configure wake up from this mode (via
rtcwake)
- true random number generator (if available on the MCU)
+ - ECDSA message signing with board private key (if available on the
+ MCU)
- MCU watchdog
- GPIO pins
- to get front button press events (the front button can be
diff --git a/drivers/platform/cznic/Makefile b/drivers/platform/cznic/Makefile
index eae4c6b341ff..af9213928404 100644
--- a/drivers/platform/cznic/Makefile
+++ b/drivers/platform/cznic/Makefile
@@ -6,3 +6,4 @@ turris-omnia-mcu-y += turris-omnia-mcu-gpio.o
turris-omnia-mcu-y += turris-omnia-mcu-sys-off-wakeup.o
turris-omnia-mcu-y += turris-omnia-mcu-trng.o
turris-omnia-mcu-y += turris-omnia-mcu-watchdog.o
+turris-omnia-mcu-$(CONFIG_DEBUG_FS) += turris-omnia-mcu-debugfs.o
diff --git a/drivers/platform/cznic/turris-omnia-mcu-base.c b/drivers/platform/cznic/turris-omnia-mcu-base.c
index 70ae5687ab4c..054c500cf676 100644
--- a/drivers/platform/cznic/turris-omnia-mcu-base.c
+++ b/drivers/platform/cznic/turris-omnia-mcu-base.c
@@ -162,6 +162,16 @@ static ssize_t board_revision_show(struct device *dev,
}
static DEVICE_ATTR_RO(board_revision);
+static ssize_t public_key_show(struct device *dev, struct device_attribute *a,
+ char *buf)
+{
+ struct omnia_mcu *mcu = i2c_get_clientdata(to_i2c_client(dev));
+
+ return sysfs_emit(buf, "%*phN\n", OMNIA_MCU_CRYPTO_PUBLIC_KEY_LEN,
+ mcu->board_public_key);
+}
+static DEVICE_ATTR_RO(public_key);
+
static struct attribute *omnia_mcu_base_attrs[] = {
&dev_attr_fw_version_hash_application.attr,
&dev_attr_fw_version_hash_bootloader.attr,
@@ -171,6 +181,7 @@ static struct attribute *omnia_mcu_base_attrs[] = {
&dev_attr_serial_number.attr,
&dev_attr_first_mac_address.attr,
&dev_attr_board_revision.attr,
+ &dev_attr_public_key.attr,
NULL
};
@@ -185,6 +196,9 @@ static umode_t omnia_mcu_base_attrs_visible(struct kobject *kobj,
a == &dev_attr_board_revision.attr) &&
!(mcu->features & OMNIA_FEAT_BOARD_INFO))
return 0;
+ else if (a == &dev_attr_public_key.attr &&
+ !(mcu->features & OMNIA_FEAT_CRYPTO))
+ return 0;
return a->mode;
}
@@ -345,6 +359,24 @@ static int omnia_mcu_read_board_info(struct omnia_mcu *mcu)
return 0;
}
+static int omnia_mcu_read_public_key(struct omnia_mcu *mcu)
+{
+ u8 reply[1 + OMNIA_MCU_CRYPTO_PUBLIC_KEY_LEN];
+ int err;
+
+ err = omnia_cmd_read(mcu->client, OMNIA_CMD_CRYPTO_GET_PUBLIC_KEY,
+ reply, sizeof(reply));
+ if (err)
+ return err;
+
+ if (reply[0] != OMNIA_MCU_CRYPTO_PUBLIC_KEY_LEN)
+ return -EIO;
+
+ memcpy(mcu->board_public_key, &reply[1], sizeof(mcu->board_public_key));
+
+ return 0;
+}
+
static int omnia_mcu_probe(struct i2c_client *client)
{
struct device *dev = &client->dev;
@@ -373,6 +405,13 @@ static int omnia_mcu_probe(struct i2c_client *client)
"Cannot read board info\n");
}
+ if (mcu->features & OMNIA_FEAT_CRYPTO) {
+ err = omnia_mcu_read_public_key(mcu);
+ if (err)
+ return dev_err_probe(dev, err,
+ "Cannot read board public key\n");
+ }
+
err = omnia_mcu_register_sys_off_and_wakeup(mcu);
if (err)
return err;
@@ -385,7 +424,11 @@ static int omnia_mcu_probe(struct i2c_client *client)
if (err)
return err;
- return omnia_mcu_register_trng(mcu);
+ err = omnia_mcu_register_trng(mcu);
+ if (err)
+ return err;
+
+ return omnia_mcu_register_debugfs(mcu);
}
static const struct of_device_id of_omnia_mcu_match[] = {
diff --git a/drivers/platform/cznic/turris-omnia-mcu-debugfs.c b/drivers/platform/cznic/turris-omnia-mcu-debugfs.c
new file mode 100644
index 000000000000..218e6035917d
--- /dev/null
+++ b/drivers/platform/cznic/turris-omnia-mcu-debugfs.c
@@ -0,0 +1,207 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * CZ.NIC's Turris Omnia MCU ECDSA message signing via debugfs
+ *
+ * 2024 by Marek Behún <[email protected]>
+ */
+
+#include <linux/bitfield.h>
+#include <linux/completion.h>
+#include <linux/debugfs.h>
+#include <linux/device.h>
+#include <linux/gpio/consumer.h>
+#include <linux/gpio/driver.h>
+#include <linux/i2c.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/string.h>
+#include <linux/turris-omnia-mcu-interface.h>
+#include <linux/types.h>
+#include <linux/uaccess.h>
+
+#include "turris-omnia-mcu.h"
+
+#define OMNIA_CMD_CRYPTO_SIGN_MESSAGE_LEN 32
+
+enum {
+ SIGN_STATE_CLOSED = 0,
+ SIGN_STATE_OPEN = 1,
+ SIGN_STATE_REQUESTED = 2,
+ SIGN_STATE_COLLECTED = 3,
+};
+
+static irqreturn_t omnia_msg_signed_irq_handler(int irq, void *dev_id)
+{
+ u8 reply[1 + OMNIA_MCU_CRYPTO_SIGNATURE_LEN];
+ struct omnia_mcu *mcu = dev_id;
+ int err;
+
+ err = omnia_cmd_read(mcu->client, OMNIA_CMD_CRYPTO_COLLECT_SIGNATURE,
+ reply, sizeof(reply));
+ if (!err && reply[0] != OMNIA_MCU_CRYPTO_SIGNATURE_LEN)
+ err = -EIO;
+
+ guard(mutex)(&mcu->sign_lock);
+
+ if (mcu->sign_state == SIGN_STATE_REQUESTED) {
+ mcu->sign_err = err;
+ if (!err)
+ memcpy(mcu->signature, &reply[1],
+ OMNIA_MCU_CRYPTO_SIGNATURE_LEN);
+ mcu->sign_state = SIGN_STATE_COLLECTED;
+ complete(&mcu->msg_signed_completion);
+ }
+
+ return IRQ_HANDLED;
+}
+
+static int do_sign_open(struct inode *inode, struct file *file)
+{
+ struct omnia_mcu *mcu = inode->i_private;
+
+ guard(mutex)(&mcu->sign_lock);
+
+ /* do_sign is allowed to be opened only once */
+ if (mcu->sign_state != SIGN_STATE_CLOSED)
+ return -EBUSY;
+
+ mcu->sign_state = SIGN_STATE_OPEN;
+
+ file->private_data = mcu;
+
+ return nonseekable_open(inode, file);
+}
+
+static int do_sign_release(struct inode *inode, struct file *file)
+{
+ struct omnia_mcu *mcu = file->private_data;
+
+ guard(mutex)(&mcu->sign_lock);
+
+ mcu->sign_state = SIGN_STATE_CLOSED;
+
+ /* forget signature on release even if it was not read, for security */
+ memzero_explicit(mcu->signature, sizeof(mcu->signature));
+
+ return 0;
+}
+
+static ssize_t do_sign_read(struct file *file, char __user *buf, size_t len,
+ loff_t *ppos)
+{
+ struct omnia_mcu *mcu = file->private_data;
+
+ /* only allow read of one whole signature */
+ if (len != sizeof(mcu->signature))
+ return -EINVAL;
+
+ scoped_guard(mutex, &mcu->sign_lock)
+ if (mcu->sign_state != SIGN_STATE_REQUESTED &&
+ mcu->sign_state != SIGN_STATE_COLLECTED)
+ return -ENODATA;
+
+ if (wait_for_completion_interruptible(&mcu->msg_signed_completion))
+ return -EINTR;
+
+ guard(mutex)(&mcu->sign_lock);
+
+ mcu->sign_state = SIGN_STATE_OPEN;
+
+ if (mcu->sign_err)
+ return mcu->sign_err;
+
+ if (copy_to_user(buf, mcu->signature, len))
+ return -EFAULT;
+
+ /* on read forget the signature, for security */
+ memzero_explicit(mcu->signature, sizeof(mcu->signature));
+
+ return len;
+}
+
+static ssize_t do_sign_write(struct file *file, const char __user *buf,
+ size_t len, loff_t *ppos)
+{
+ u8 cmd[1 + OMNIA_CMD_CRYPTO_SIGN_MESSAGE_LEN], reply;
+ struct omnia_mcu *mcu = file->private_data;
+ int err;
+
+ /*
+ * the input is a SHA-256 hash of a message to sign, so exactly
+ * 32 bytes have to be read
+ */
+ if (len != OMNIA_CMD_CRYPTO_SIGN_MESSAGE_LEN)
+ return -EINVAL;
+
+ cmd[0] = OMNIA_CMD_CRYPTO_SIGN_MESSAGE;
+
+ if (copy_from_user(&cmd[1], buf, len))
+ return -EFAULT;
+
+ guard(mutex)(&mcu->sign_lock);
+
+ if (mcu->sign_state != SIGN_STATE_OPEN)
+ return -EBUSY;
+
+ err = omnia_cmd_write_read(mcu->client, cmd, sizeof(cmd), &reply, 1);
+ if (err)
+ return err;
+
+ if (reply)
+ mcu->sign_state = SIGN_STATE_REQUESTED;
+
+ return reply ? len : -EBUSY;
+}
+
+static const struct file_operations do_sign_fops = {
+ .owner = THIS_MODULE,
+ .open = do_sign_open,
+ .read = do_sign_read,
+ .write = do_sign_write,
+ .release = do_sign_release,
+ .llseek = no_llseek,
+};
+
+static void omnia_debugfs_drop_dir(void *res)
+{
+ debugfs_remove_recursive(res);
+}
+
+int omnia_mcu_register_debugfs(struct omnia_mcu *mcu)
+{
+ struct device *dev = &mcu->client->dev;
+ struct dentry *root;
+ int irq, err;
+ u8 irq_idx;
+
+ if (!(mcu->features & OMNIA_FEAT_CRYPTO))
+ return 0;
+
+ irq_idx = omnia_int_to_gpio_idx[__bf_shf(OMNIA_INT_MESSAGE_SIGNED)];
+ irq = gpiod_to_irq(gpiochip_get_desc(&mcu->gc, irq_idx));
+ if (irq < 0)
+ return dev_err_probe(dev, irq,
+ "Cannot get MESSAGE_SIGNED IRQ\n");
+
+ err = devm_mutex_init(dev, &mcu->sign_lock);
+ if (err)
+ return err;
+
+ mcu->sign_state = 0;
+
+ init_completion(&mcu->msg_signed_completion);
+
+ err = devm_request_threaded_irq(dev, irq, NULL,
+ omnia_msg_signed_irq_handler,
+ IRQF_ONESHOT,
+ "turris-omnia-mcu-debugfs", mcu);
+ if (err)
+ return dev_err_probe(dev, err,
+ "Cannot request MESSAGE_SIGNED IRQ\n");
+
+ root = debugfs_create_dir("turris-omnia-mcu", NULL);
+ debugfs_create_file_unsafe("do_sign", 0600, root, mcu, &do_sign_fops);
+
+ return devm_add_action_or_reset(dev, omnia_debugfs_drop_dir, root);
+}
diff --git a/drivers/platform/cznic/turris-omnia-mcu.h b/drivers/platform/cznic/turris-omnia-mcu.h
index ef0b7dd6e485..4c013150a5e7 100644
--- a/drivers/platform/cznic/turris-omnia-mcu.h
+++ b/drivers/platform/cznic/turris-omnia-mcu.h
@@ -21,6 +21,9 @@
#include <asm/byteorder.h>
#include <asm/unaligned.h>
+#define OMNIA_MCU_CRYPTO_PUBLIC_KEY_LEN 33
+#define OMNIA_MCU_CRYPTO_SIGNATURE_LEN 64
+
struct i2c_client;
struct omnia_mcu {
@@ -32,6 +35,7 @@ struct omnia_mcu {
u64 board_serial_number;
u8 board_first_mac[ETH_ALEN];
u8 board_revision;
+ u8 board_public_key[OMNIA_MCU_CRYPTO_PUBLIC_KEY_LEN];
/* GPIO chip */
struct gpio_chip gc;
@@ -53,6 +57,16 @@ struct omnia_mcu {
/* true random number generator */
struct hwrng trng;
struct completion trng_completion;
+
+#ifdef CONFIG_DEBUG_FS
+ /* MCU ECDSA message signing via debugfs */
+ struct dentry *debugfs_root;
+ struct completion msg_signed_completion;
+ struct mutex sign_lock;
+ unsigned int sign_state;
+ u8 signature[OMNIA_MCU_CRYPTO_SIGNATURE_LEN];
+ int sign_err;
+#endif
};
int omnia_cmd_write_read(const struct i2c_client *client,
@@ -184,4 +198,13 @@ int omnia_mcu_register_sys_off_and_wakeup(struct omnia_mcu *mcu);
int omnia_mcu_register_trng(struct omnia_mcu *mcu);
int omnia_mcu_register_watchdog(struct omnia_mcu *mcu);
+#ifdef CONFIG_DEBUG_FS
+int omnia_mcu_register_debugfs(struct omnia_mcu *mcu);
+#else
+static inline int omnia_mcu_register_debugfs(struct omnia_mcu *mcu)
+{
+ return 0;
+}
+#endif
+
#endif /* __TURRIS_OMNIA_MCU_H */
--
2.43.2
On Wed, May 08, 2024 at 12:31:09PM +0200, Marek Beh?n wrote:
> Hello Andy, Hans, Ilpo, Arnd, Gregory, and others,
>
> this is v9 of the series adding Turris Omnia MCU driver.
>
> This series still depends on the immutable branch between LEDs and
> locking, introducing devm_mutex_init(), see the PR
> https://lore.kernel.org/linux-leds/[email protected]/
>
> See also cover letters for v1, v2, v3, v4, v5, v6, v7 and v8:
> https://patchwork.kernel.org/project/linux-soc/cover/[email protected]/
> https://patchwork.kernel.org/project/linux-soc/cover/[email protected]/
> https://patchwork.kernel.org/project/linux-soc/cover/[email protected]/
> https://patchwork.kernel.org/project/linux-soc/cover/[email protected]/
> https://patchwork.kernel.org/project/linux-soc/cover/[email protected]/
> https://patchwork.kernel.org/project/linux-soc/cover/[email protected]/
> https://patchwork.kernel.org/project/linux-soc/cover/[email protected]/
> https://patchwork.kernel.org/project/linux-soc/cover/[email protected]/
From GPIO implementation perspective, it's good enough in my opinion. The rest
can be amended later on.
--
With Best Regards,
Andy Shevchenko
On Wed, May 08, 2024 at 12:31:16PM +0200, Marek Beh?n wrote:
> Add support for digital message signing with private key stored in the
> MCU. Boards with MKL MCUs have a NIST256p ECDSA private key created
> when manufactured. The private key is not readable from the MCU, but
> MCU allows for signing messages with it and retrieving the public key.
>
> As described in a similar commit 50524d787de3 ("firmware:
> turris-mox-rwtm: support ECDSA signatures via debugfs"):
> The optimal solution would be to register an akcipher provider via
> kernel's crypto API, but crypto API does not yet support accessing
> akcipher API from userspace (and probably won't for some time, see
> https://www.spinics.net/lists/linux-crypto/msg38388.html).
>
> Therefore we add support for accessing this signature generation
> mechanism via debugfs for now, so that userspace can access it.
...
> +static irqreturn_t omnia_msg_signed_irq_handler(int irq, void *dev_id)
> +{
> + u8 reply[1 + OMNIA_MCU_CRYPTO_SIGNATURE_LEN];
> + struct omnia_mcu *mcu = dev_id;
> + int err;
> +
> + err = omnia_cmd_read(mcu->client, OMNIA_CMD_CRYPTO_COLLECT_SIGNATURE,
> + reply, sizeof(reply));
> + if (!err && reply[0] != OMNIA_MCU_CRYPTO_SIGNATURE_LEN)
> + err = -EIO;
> +
> + guard(mutex)(&mcu->sign_lock);
> +
> + if (mcu->sign_state == SIGN_STATE_REQUESTED) {
> + mcu->sign_err = err;
> + if (!err)
> + memcpy(mcu->signature, &reply[1],
> + OMNIA_MCU_CRYPTO_SIGNATURE_LEN);
> + mcu->sign_state = SIGN_STATE_COLLECTED;
Even for an error case?
> + complete(&mcu->msg_signed_completion);
> + }
> +
> + return IRQ_HANDLED;
> +}
...
> + scoped_guard(mutex, &mcu->sign_lock)
> + if (mcu->sign_state != SIGN_STATE_REQUESTED &&
> + mcu->sign_state != SIGN_STATE_COLLECTED)
> + return -ENODATA;
{}
Don't you want interruptible mutex? In such case you might need to return
-ERESTARTSYS. OTOH, this is debugfs, we don't much care.
...
> +#define OMNIA_MCU_CRYPTO_PUBLIC_KEY_LEN 33
33? Hmm... does it mean (32 + 1)?
--
With Best Regards,
Andy Shevchenko
On Wed, May 08, 2024 at 02:17:24PM +0300, Andy Shevchenko wrote:
> On Wed, May 08, 2024 at 12:31:09PM +0200, Marek Beh?n wrote:
> > Hello Andy, Hans, Ilpo, Arnd, Gregory, and others,
> >
> > this is v9 of the series adding Turris Omnia MCU driver.
> >
> > This series still depends on the immutable branch between LEDs and
> > locking, introducing devm_mutex_init(), see the PR
> > https://lore.kernel.org/linux-leds/[email protected]/
> >
> > See also cover letters for v1, v2, v3, v4, v5, v6, v7 and v8:
> > https://patchwork.kernel.org/project/linux-soc/cover/[email protected]/
> > https://patchwork.kernel.org/project/linux-soc/cover/[email protected]/
> > https://patchwork.kernel.org/project/linux-soc/cover/[email protected]/
> > https://patchwork.kernel.org/project/linux-soc/cover/[email protected]/
> > https://patchwork.kernel.org/project/linux-soc/cover/[email protected]/
> > https://patchwork.kernel.org/project/linux-soc/cover/[email protected]/
> > https://patchwork.kernel.org/project/linux-soc/cover/[email protected]/
> > https://patchwork.kernel.org/project/linux-soc/cover/[email protected]/
>
> From GPIO implementation perspective, it's good enough in my opinion. The rest
> can be amended later on.
I will send v10 tomorrow with these issues fixed. We'll see if Arnd will
be willing to take this for 6.10, and if not, 6.11 will it be.
Marek