[PATCH v12 0/8] Turris Omnia MCU driver

[PATCH v12 0/8] Turris Omnia MCU driver

[Marek Behún]

Hello Andy, Hans, Ilpo, Arnd, Gregory, and others,

this is v12 of the series adding Turris Omnia MCU driver.

Changes since v11:
- fixed some includes, suggested by Andy
- moved #include <linux/turris-omnia-mcu-interface.h> after the other
  includes, since it is domain specific, suggested by Andy
- in patch 2, use sizeof() of dest buffer in memcpy call, instead of
  ETH_ALEN constant, as suggested by Andy
- in patch 3, dropped the .has_int member of omnia GPIO definition
  structure, and added is_int_bit_valid() function instead, as suggested
  by Andy
- in patch 3, changed int to unsigned int where appropriate, as
  suggested by Andy
- in patch 3, fixed docstring indentation, suggested by Andy
- in patch 4 dropped #include <linux/rtc.h>, and instead declared struct
  rtc_device, it is only used as a pointer, suggested by Andy
- in patch 5, renamed the completion from trng_completion to
  trng_entropy_available
- in patch 5, use gpio_device_get_desc() instead of gpiochip_get_desc()
  when mapping IRQ (as discussed with Andy and Bart)
- in patch 5, dropped setting the priv member of hwrng, and instead use
  container_of() to get the driver private structure, suggested by
  Herbert

Links to previous cover letters (v1 to v11):
  https://patchwork.kernel.org/project/linux-soc/cover/20230823161012.6986-1-kabel@kernel.org/
  https://patchwork.kernel.org/project/linux-soc/cover/20230919103815.16818-1-kabel@kernel.org/
  https://patchwork.kernel.org/project/linux-soc/cover/20231023143130.11602-1-kabel@kernel.org/
  https://patchwork.kernel.org/project/linux-soc/cover/20231026161803.16750-1-kabel@kernel.org/
  https://patchwork.kernel.org/project/linux-soc/cover/20240323164359.21642-1-kabel@kernel.org/
  https://patchwork.kernel.org/project/linux-soc/cover/20240418121116.22184-1-kabel@kernel.org/
  https://patchwork.kernel.org/project/linux-soc/cover/20240424173809.7214-1-kabel@kernel.org/
  https://patchwork.kernel.org/project/linux-soc/cover/20240430115111.3453-1-kabel@kernel.org/
  https://patchwork.kernel.org/project/linux-soc/cover/20240508103118.23345-1-kabel@kernel.org/
  https://patchwork.kernel.org/project/linux-soc/cover/20240510101819.13551-1-kabel@kernel.org/
  https://patchwork.kernel.org/project/linux-soc/cover/20240605161851.13911-1-kabel@kernel.org/

Marek Behún (8):
  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
  ARM: dts: turris-omnia: Add MCU system-controller node
  ARM: dts: turris-omnia: Add GPIO key node for front button

 .../sysfs-bus-i2c-devices-turris-omnia-mcu    |  113 ++
 .../firmware/cznic,turris-omnia-mcu.yaml      |   86 ++
 MAINTAINERS                                   |    4 +
 .../dts/marvell/armada-385-turris-omnia.dts   |   35 +-
 drivers/platform/Kconfig                      |    2 +
 drivers/platform/Makefile                     |    1 +
 drivers/platform/cznic/Kconfig                |   48 +
 drivers/platform/cznic/Makefile               |    8 +
 .../platform/cznic/turris-omnia-mcu-base.c    |  408 +++++++
 .../platform/cznic/turris-omnia-mcu-gpio.c    | 1088 +++++++++++++++++
 .../cznic/turris-omnia-mcu-sys-off-wakeup.c   |  260 ++++
 .../platform/cznic/turris-omnia-mcu-trng.c    |  103 ++
 .../cznic/turris-omnia-mcu-watchdog.c         |  130 ++
 drivers/platform/cznic/turris-omnia-mcu.h     |  194 +++
 include/linux/turris-omnia-mcu-interface.h    |  249 ++++
 15 files changed, 2728 insertions(+), 1 deletion(-)
 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-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

-- 
2.44.2

[PATCH v12 6/8] platform: cznic: turris-omnia-mcu: Add support for MCU provided TRNG

[Marek Behún]

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 <kabel@kernel.org>
---
 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 2d8e5c9a8dd1..c68a7a84a951 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 471dda5d7e1c..2d970c7f1937 100644
--- a/drivers/platform/cznic/turris-omnia-mcu-gpio.c
+++ b/drivers/platform/cznic/turris-omnia-mcu-gpio.c
@@ -188,7 +188,7 @@ 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..ad953fb3c37a
--- /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 <kabel@kernel.org>
+ */
+
+#include <linux/bitfield.h>
+#include <linux/completion.h>
+#include <linux/container_of.h>
+#include <linux/errno.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/string.h>
+#include <linux/types.h>
+
+#include <linux/turris-omnia-mcu-interface.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_entropy_ready);
+
+	return IRQ_HANDLED;
+}
+
+static int omnia_trng_read(struct hwrng *rng, void *data, size_t max, bool wait)
+{
+	struct omnia_mcu *mcu = container_of(rng, struct omnia_mcu, trng);
+	u8 reply[1 + OMNIA_CMD_TRNG_MAX_ENTROPY_LEN];
+	int err, bytes;
+
+	if (!wait && !completion_done(&mcu->trng_entropy_ready))
+		return 0;
+
+	do {
+		if (wait_for_completion_interruptible(&mcu->trng_entropy_ready))
+			return -ERESTARTSYS;
+
+		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(gpio_device_get_desc(mcu->gc.gpiodev, irq_idx));
+	if (!irq)
+		return dev_err_probe(dev, -ENXIO, "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_entropy_ready);
+
+	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;
+
+	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 dc59f415f611..2ca56ae13aa9 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/types.h>
@@ -47,6 +49,10 @@ struct omnia_mcu {
 
 	/* MCU watchdog */
 	struct watchdog_device wdt;
+
+	/* true random number generator */
+	struct hwrng trng;
+	struct completion trng_entropy_ready;
 };
 
 int omnia_cmd_write_read(const struct i2c_client *client,
@@ -176,11 +182,13 @@ 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 */
-- 
2.44.2

Re: [PATCH v12 0/8] Turris Omnia MCU driver

[Marek Behún]

Hi Arnd,

will you be merging this series?

Thanks.

Marek

Re: [PATCH v12 0/8] Turris Omnia MCU driver

[Marek Behún]

On Mon, 1 Jul 2024 10:41:15 +0200
Marek Behún <kabel@kernel.org> wrote:

> Hi Arnd,
> 
> will you be merging this series?

Just to clear up, I wanted to ask whether you will be merging or
someone else should take stuff to drivers/platform.

Anyway, I sent v13 with one more cosmetic change, requested by Bart.

Marek