diff mbox series

[v8,2/9] platform: cznic: Add preliminary support for Turris Omnia MCU

Message ID 20240430115111.3453-3-kabel@kernel.org
State New
Headers show
Series None | expand

Commit Message

Marek Behún April 30, 2024, 11:51 a.m. UTC 
Add the basic skeleton for a new platform driver for the microcontroller
found on the Turris Omnia board.

Signed-off-by: Marek Behún <kabel@kernel.org>
---
 .../sysfs-bus-i2c-devices-turris-omnia-mcu    |  81 ++++
 MAINTAINERS                                   |   3 +
 drivers/platform/Kconfig                      |   2 +
 drivers/platform/Makefile                     |   1 +
 drivers/platform/cznic/Kconfig                |  26 ++
 drivers/platform/cznic/Makefile               |   4 +
 .../platform/cznic/turris-omnia-mcu-base.c    | 376 ++++++++++++++++++
 drivers/platform/cznic/turris-omnia-mcu.h     |  50 +++
 include/linux/turris-omnia-mcu-interface.h    | 249 ++++++++++++
 9 files changed, 792 insertions(+)
 create mode 100644 Documentation/ABI/testing/sysfs-bus-i2c-devices-turris-omnia-mcu
 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.h
 create mode 100644 include/linux/turris-omnia-mcu-interface.h

Comments

Andy Shevchenko April 30, 2024, 3:17 p.m. UTC | #1 
On Tue, Apr 30, 2024 at 04:05:07PM +0200, Marek Behún wrote:
> On Tue, 30 Apr 2024 15:53:51 +0300
> Andy Shevchenko <andy.shevchenko@gmail.com> wrote:
> > On Tue, Apr 30, 2024 at 2:51 PM Marek Behún <kabel@kernel.org> wrote:

...

> > > +static int omnia_get_version_hash(struct omnia_mcu *mcu, bool bootloader,
> > > +                                 u8 version[static OMNIA_FW_VERSION_HEX_LEN])
> > 
> > Interesting format of the last parameter. Does it make any difference
> > to the compiler if you use u8 *version?
> 
> The compiler will warn if an array with not enough space is passed as
> argument.

Really?

> > > +{
> > > +       u8 reply[OMNIA_FW_VERSION_LEN];
> > > +       int err;
> > > +
> > > +       err = omnia_cmd_read(mcu->client,
> > > +                            bootloader ? CMD_GET_FW_VERSION_BOOT
> > > +                                       : CMD_GET_FW_VERSION_APP,
> > > +                            reply, sizeof(reply));
> > > +       if (err)
> > > +               return err;  
> > 
> > > +       version[OMNIA_FW_VERSION_HEX_LEN - 1] = '\0';
> > > +       bin2hex(version, reply, OMNIA_FW_VERSION_LEN);  
> > 
> > Hmm... I would rather use returned value
> > 
> > char *p;
> > 
> > p = bin2hex(...);
> > *p = '\0';
> > 
> > return 0;
> 
> OK. I guess
> 
>   *bin2hex(version, reply, OMNIA_FW_VERSION_LEN) = '\0';
> 
> would be too crazy, right?

Yes, it's not a Python :-)

> > > +       return 0;
> > > +}  

...

> > > +               dev_err(dev, "Cannot read MCU %s firmware version: %d\n", type,
> > > +                       err);  
> > 
> > One  line?
> 
> I'd like to keep this driver to 80 columns.

Then better to have a logical split then?

			dev_err(dev, "Cannot read MCU %s firmware version: %d\n",
				type, err);

...

> > > +               omnia_info_missing_feature(dev, "feature reading");  
> > 
> > Tautology. Read the final message. I believe you wanted to pass just
> > "reading" here.
> 
> No, I actually wanted it to print
>   Your board's MCU firmware does not support the feature reading
>   feature.
> as in the feature "feature reading" is not supported.
> I guess I could change it to
>   Your board's MCU firmware does not support the feature reading.
> but that would complicate the code: either I would need to add
> " feature" suffix to all the features[].name, or duplicate the
> info string from the omnia_info_missing_feature() function.
Ilpo Järvinen April 30, 2024, 3:31 p.m. UTC | #2 
On Tue, 30 Apr 2024, Marek Behún wrote:

> Add the basic skeleton for a new platform driver for the microcontroller
> found on the Turris Omnia board.
> 
> Signed-off-by: Marek Behún <kabel@kernel.org>

> +	struct device *dev = &mcu->client->dev;
> +	bool suggest_fw_upgrade = false;
> +	int status;
> +
> +	/* status word holds MCU type, which we need below */
> +	status = omnia_cmd_read_u16(mcu->client, CMD_GET_STATUS_WORD);
> +	if (status < 0)
> +		return status;
> +
> +	/* check whether MCU firmware supports the CMD_GET_FEAUTRES command */

FEATURES

> +	if (status & STS_FEATURES_SUPPORTED) {
> +		__le32 reply;
> +		int ret;
> +
> +		/* try read 32-bit features */
> +		ret = omnia_cmd_read(mcu->client, CMD_GET_FEATURES, &reply,
> +				     sizeof(reply));
> +		if (ret) {
> +			/* try read 16-bit features */
> +			ret = omnia_cmd_read_u16(mcu->client, CMD_GET_FEATURES);
> +			if (ret < 0)
> +				return ret;
> +
> +			mcu->features = ret;
> +		} else {
> +			mcu->features = le32_to_cpu(reply);
> +
> +			if (mcu->features & FEAT_FROM_BIT_16_INVALID)
> +				mcu->features &= GENMASK(15, 0);
> +		}

I'm not a big fan of the inconsistency here when it comes to who handles 
the endianness, perhaps there is a good reason for that but it looks a bit 
odd to have it done in a different way for 32-bit and 16-bit.

> +	} else {
> +		omnia_info_missing_feature(dev, "feature reading");
> +		suggest_fw_upgrade = true;
> +	}
> +
> +	mcu->type = omnia_status_to_mcu_type(status);
> +	dev_info(dev, "MCU type %s%s\n", mcu->type,
> +		 (mcu->features & FEAT_PERIPH_MCU) ?
> +			", with peripheral resets wired" : "");
> +
> +	omnia_mcu_print_version_hash(mcu, true);
> +
> +	if (mcu->features & FEAT_BOOTLOADER)
> +		dev_warn(dev,
> +			 "MCU is running bootloader firmware. Was firmware upgrade interrupted?\n");
> +	else
> +		omnia_mcu_print_version_hash(mcu, false);
> +
> +	for (unsigned int i = 0; i < ARRAY_SIZE(features); i++) {
> +		if (mcu->features & features[i].mask)
> +			continue;
> +
> +		omnia_info_missing_feature(dev, features[i].name);
> +		suggest_fw_upgrade = true;
> +	}
> +
> +	if (suggest_fw_upgrade)
> +		dev_info(dev,
> +			 "Consider upgrading MCU firmware with the omnia-mcutool utility.\n");
> +
> +	return 0;
> +}

> +int omnia_cmd_read(const struct i2c_client *client, u8 cmd, void *reply,
> +		   unsigned int len);
> +
> +static inline int omnia_cmd_read_u16(const struct i2c_client *client, u8 cmd)
> +{
> +	__le16 reply;
> +	int err;
> +
> +	err = omnia_cmd_read(client, cmd, &reply, sizeof(reply));
> +
> +	return err ?: le16_to_cpu(reply);
> +}
> +
> +static inline int omnia_cmd_read_u8(const struct i2c_client *client, u8 cmd)
> +{
> +	u8 reply;
> +	int err;
> +
> +	err = omnia_cmd_read(client, cmd, &reply, sizeof(reply));
> +
> +	return err ?: reply;
> +}
> +
> +#endif /* __TURRIS_OMNIA_MCU_H */


> diff --git a/include/linux/turris-omnia-mcu-interface.h b/include/linux/turris-omnia-mcu-interface.h
> new file mode 100644
> index 000000000000..88f8490b5897
> --- /dev/null
> +++ b/include/linux/turris-omnia-mcu-interface.h
> @@ -0,0 +1,249 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * CZ.NIC's Turris Omnia MCU I2C interface commands definitions
> + *
> + * 2024 by Marek Behún <kabel@kernel.org>
> + */
> +
> +#ifndef __TURRIS_OMNIA_MCU_INTERFACE_H
> +#define __TURRIS_OMNIA_MCU_INTERFACE_H
> +
> +#include <linux/bitfield.h>
> +#include <linux/bits.h>
> +
> +enum omnia_commands_e {
> +	CMD_GET_STATUS_WORD		= 0x01, /* slave sends status word back */
> +	CMD_GENERAL_CONTROL		= 0x02,
> +	CMD_LED_MODE			= 0x03, /* default/user */
> +	CMD_LED_STATE			= 0x04, /* LED on/off */
> +	CMD_LED_COLOR			= 0x05, /* LED number + RED + GREEN + BLUE */
> +	CMD_USER_VOLTAGE		= 0x06,
> +	CMD_SET_BRIGHTNESS		= 0x07,
> +	CMD_GET_BRIGHTNESS		= 0x08,
> +	CMD_GET_RESET			= 0x09,
> +	CMD_GET_FW_VERSION_APP		= 0x0A, /* 20B git hash number */
> +	CMD_SET_WATCHDOG_STATE		= 0x0B, /* 0 - disable
> +						 * 1 - enable / ping
> +						 * after boot watchdog is started
> +						 * with 2 minutes timeout
> +						 */
> +
> +	/* CMD_WATCHDOG_STATUS		= 0x0C, not implemented anymore */
> +
> +	CMD_GET_WATCHDOG_STATE		= 0x0D,
> +	CMD_GET_FW_VERSION_BOOT		= 0x0E, /* 20B git hash number */
> +	CMD_GET_FW_CHECKSUM		= 0x0F, /* 4B length, 4B checksum */
> +
> +	/* available if FEATURES_SUPPORTED bit set in status word */
> +	CMD_GET_FEATURES		= 0x10,
> +
> +	/* available if EXT_CMD bit set in features */
> +	CMD_GET_EXT_STATUS_DWORD	= 0x11,
> +	CMD_EXT_CONTROL			= 0x12,
> +	CMD_GET_EXT_CONTROL_STATUS	= 0x13,
> +
> +	/* available if NEW_INT_API bit set in features */
> +	CMD_GET_INT_AND_CLEAR		= 0x14,
> +	CMD_GET_INT_MASK		= 0x15,
> +	CMD_SET_INT_MASK		= 0x16,
> +
> +	/* available if FLASHING bit set in features */
> +	CMD_FLASH			= 0x19,
> +
> +	/* available if WDT_PING bit set in features */
> +	CMD_SET_WDT_TIMEOUT		= 0x20,
> +	CMD_GET_WDT_TIMELEFT		= 0x21,
> +
> +	/* available if POWEROFF_WAKEUP bit set in features */
> +	CMD_SET_WAKEUP			= 0x22,
> +	CMD_GET_UPTIME_AND_WAKEUP	= 0x23,
> +	CMD_POWER_OFF			= 0x24,
> +
> +	/* available if USB_OVC_PROT_SETTING bit set in features */
> +	CMD_SET_USB_OVC_PROT		= 0x25,
> +	CMD_GET_USB_OVC_PROT		= 0x26,
> +
> +	/* available if TRNG bit set in features */
> +	CMD_TRNG_COLLECT_ENTROPY	= 0x28,
> +
> +	/* available if CRYPTO bit set in features */
> +	CMD_CRYPTO_GET_PUBLIC_KEY	= 0x29,
> +	CMD_CRYPTO_SIGN_MESSAGE		= 0x2A,
> +	CMD_CRYPTO_COLLECT_SIGNATURE	= 0x2B,
> +
> +	/* available if BOARD_INFO it set in features */
> +	CMD_BOARD_INFO_GET		= 0x2C,
> +	CMD_BOARD_INFO_BURN		= 0x2D,
> +
> +	/* available only at address 0x2b (led-controller) */
> +	/* available only if LED_GAMMA_CORRECTION bit set in features */
> +	CMD_SET_GAMMA_CORRECTION	= 0x30,
> +	CMD_GET_GAMMA_CORRECTION	= 0x31,
> +
> +	/* available only at address 0x2b (led-controller) */
> +	/* available only if PER_LED_CORRECTION bit set in features */
> +	/* available only if FROM_BIT_16_INVALID bit NOT set in features */
> +	CMD_SET_LED_CORRECTIONS		= 0x32,
> +	CMD_GET_LED_CORRECTIONS		= 0x33,
> +};
> +
> +enum omnia_flashing_commands_e {
> +	FLASH_CMD_UNLOCK		= 0x01,
> +	FLASH_CMD_SIZE_AND_CSUM		= 0x02,
> +	FLASH_CMD_PROGRAM		= 0x03,
> +	FLASH_CMD_RESET			= 0x04,
> +};

I'm bit worried about many items above, they seem generic enough they 
could trigger name conflict at some point. Could these all defines be 
prefixed so there's no risk of collisions.

> +enum omnia_sts_word_e {
> +	STS_MCU_TYPE_MASK			= GENMASK(1, 0),
> +	STS_MCU_TYPE_STM32			= 0 << 0,
> +	STS_MCU_TYPE_GD32			= 1 << 0,
> +	STS_MCU_TYPE_MKL			= 2 << 0,

These are FIELD_PREP(STS_MCU_TYPE_MASK, x), although I suspect you need to 
use FIELD_PREP_CONST() in this context. If neither ends up working in this 
context, then leave it as is.

> +	STS_FEATURES_SUPPORTED			= BIT(2),
> +	STS_USER_REGULATOR_NOT_SUPPORTED	= BIT(3),
> +	STS_CARD_DET				= BIT(4),
> +	STS_MSATA_IND				= BIT(5),
> +	STS_USB30_OVC				= BIT(6),
> +	STS_USB31_OVC				= BIT(7),
> +	STS_USB30_PWRON				= BIT(8),
> +	STS_USB31_PWRON				= BIT(9),
> +	STS_ENABLE_4V5				= BIT(10),
> +	STS_BUTTON_MODE				= BIT(11),
> +	STS_BUTTON_PRESSED			= BIT(12),
> +	STS_BUTTON_COUNTER_MASK			= GENMASK(15, 13)
> +};
> +
> +enum omnia_ctl_byte_e {
> +	CTL_LIGHT_RST		= BIT(0),
> +	CTL_HARD_RST		= BIT(1),
> +	/* BIT(2) is currently reserved */
> +	CTL_USB30_PWRON		= BIT(3),
> +	CTL_USB31_PWRON		= BIT(4),
> +	CTL_ENABLE_4V5		= BIT(5),
> +	CTL_BUTTON_MODE		= BIT(6),
> +	CTL_BOOTLOADER		= BIT(7)
> +};
> +
> +enum omnia_features_e {
> +	FEAT_PERIPH_MCU			= BIT(0),
> +	FEAT_EXT_CMDS			= BIT(1),
> +	FEAT_WDT_PING			= BIT(2),
> +	FEAT_LED_STATE_EXT_MASK		= GENMASK(4, 3),
> +	FEAT_LED_STATE_EXT		= 1 << 3,
> +	FEAT_LED_STATE_EXT_V32		= 2 << 3,

Ditto.

> +	FEAT_LED_GAMMA_CORRECTION	= BIT(5),
> +	FEAT_NEW_INT_API		= BIT(6),
> +	FEAT_BOOTLOADER			= BIT(7),
> +	FEAT_FLASHING			= BIT(8),
> +	FEAT_NEW_MESSAGE_API		= BIT(9),
> +	FEAT_BRIGHTNESS_INT		= BIT(10),
> +	FEAT_POWEROFF_WAKEUP		= BIT(11),
> +	FEAT_CAN_OLD_MESSAGE_API	= BIT(12),
> +	FEAT_TRNG			= BIT(13),
> +	FEAT_CRYPTO			= BIT(14),
> +	FEAT_BOARD_INFO			= BIT(15),
> +
> +	/*
> +	 * Orginally the features command replied only 16 bits. If more were
> +	 * read, either the I2C transaction failed or 0xff bytes were sent.
> +	 * Therefore to consider bits 16 - 31 valid, one bit (20) was reserved
> +	 * to be zero.
> +	 */
> +
> +	/* Bits 16 - 19 correspond to bits 0 - 3 of status word */
> +	FEAT_MCU_TYPE_MASK		= GENMASK(17, 16),
> +	FEAT_MCU_TYPE_STM32		= 0 << 16,
> +	FEAT_MCU_TYPE_GD32		= 1 << 16,
> +	FEAT_MCU_TYPE_MKL		= 2 << 16,

Ditto.
Marek Behún May 2, 2024, 6:40 p.m. UTC | #3 
On Tue, Apr 30, 2024 at 06:17:45PM +0300, Andy Shevchenko wrote:
> On Tue, Apr 30, 2024 at 04:05:07PM +0200, Marek Behún wrote:
> > On Tue, 30 Apr 2024 15:53:51 +0300
> > Andy Shevchenko <andy.shevchenko@gmail.com> wrote:
> > > On Tue, Apr 30, 2024 at 2:51 PM Marek Behún <kabel@kernel.org> wrote:
> 
> ...
> 
> > > > +static int omnia_get_version_hash(struct omnia_mcu *mcu, bool bootloader,
> > > > +                                 u8 version[static OMNIA_FW_VERSION_HEX_LEN])
> > > 
> > > Interesting format of the last parameter. Does it make any difference
> > > to the compiler if you use u8 *version?
> > 
> > The compiler will warn if an array with not enough space is passed as
> > argument.
> 
> Really?

Indeed:

  extern void a(char *x);

  static void b(char x[static 10]) {
      a(x);
  }

  void c(void) {
      char x[5] = "abcd";
      b(x);
  }

says:
  test.c: In function ‘c’:
  test.c:9:9: warning: ‘b’ accessing 10 bytes in a region of size 5 [-Wstringop-overflow=]
      9 |         b(x);
        |         ^~~~
  test.c:9:9: note: referencing argument 1 of type ‘char[10]’
  test.c:3:13: note: in a call to function ‘b’
      3 | static void b(char x[static 10]) {
        |

...

> > > > +               dev_err(dev, "Cannot read MCU %s firmware version: %d\n", type,
> > > > +                       err);  
> > > 
> > > One  line?
> > 
> > I'd like to keep this driver to 80 columns.
> 
> Then better to have a logical split then?
> 
> 			dev_err(dev, "Cannot read MCU %s firmware version: %d\n",
> 				type, err);

OK

> > > > +               omnia_info_missing_feature(dev, "feature reading");  
> > > 
> > > Tautology. Read the final message. I believe you wanted to pass just
> > > "reading" here.
> > 
> > No, I actually wanted it to print
> >   Your board's MCU firmware does not support the feature reading
> >   feature.
> > as in the feature "feature reading" is not supported.
> > I guess I could change it to
> >   Your board's MCU firmware does not support the feature reading.
> > but that would complicate the code: either I would need to add
> > " feature" suffix to all the features[].name, or duplicate the
> > info string from the omnia_info_missing_feature() function.
> 
> From point of a mere user (as I am towards this driver) I consider
> the tautology confusing.
> 
> 	...the 'reading' feature
> 
> may be a good compromise.

I have rewritten it to use another dev_info:
  dev_info(dev,
           "Your board's MCU firmware does not support feature reading.\n");

> 
> ...
> 
> > > > +       memcpy(mcu->board_first_mac, &reply[9], ETH_ALEN);  
> > > 
> > > There is an API ether_copy_addr() or so, don't remember by heart.
> > > You also need an include for ETH_ALEN definition.
> > 
> > Doc for ether_addr_copy says:
> >   Please note: dst & src must both be aligned to u16.
> > since the code does:
> >   u16 *a = (u16 *)dst;
> >   const u16 *b = (const u16 *)src;
> > 
> >   a[0] = b[0];
> >   a[1] = b[1];
> >   a[2] = b[2]
> > 
> > Since I am copying from &reply[9], which is not u16-aligned, this won't
> > work.
> 
> It would work on architectures that support misaligned accesses, but in general
> you are right. Perhaps a comment on top to avoid "cleanup" patches like this?


OK
 
> > > > +enum omnia_ctl_byte_e {
> > > > +       CTL_LIGHT_RST           = BIT(0),
> > > > +       CTL_HARD_RST            = BIT(1),
> > > > +       /* BIT(2) is currently reserved */
> > > > +       CTL_USB30_PWRON         = BIT(3),
> > > > +       CTL_USB31_PWRON         = BIT(4),
> > > > +       CTL_ENABLE_4V5          = BIT(5),
> > > > +       CTL_BUTTON_MODE         = BIT(6),
> > > > +       CTL_BOOTLOADER          = BIT(7)  
> > > 
> > > Keep trailing comma as it might be extended (theoretically). And you
> > > do the similar in other enums anyway.
> > 
> > ctl_byt is 8-bit, so this enum really can't be extended.
> 
> I understand that (even before writing the previous reply).
> 
> > In fact I need
> > to drop the last comma from omnia_ext_sts_dword_e and omnia_int_e.
> 
> Who prevents from having in a new firmware let's say
> 
>  BIT(31) | BIT(1)
> 
> as a new value?
> 
> From Linux perspective these are not terminating lines.

OK
Andy Shevchenko May 2, 2024, 6:47 p.m. UTC | #4 
On Thu, May 2, 2024 at 9:40 PM Marek Behún <kabel@kernel.org> wrote:
> On Tue, Apr 30, 2024 at 06:17:45PM +0300, Andy Shevchenko wrote:
> > On Tue, Apr 30, 2024 at 04:05:07PM +0200, Marek Behún wrote:
> > > On Tue, 30 Apr 2024 15:53:51 +0300
> > > Andy Shevchenko <andy.shevchenko@gmail.com> wrote:
> > > > On Tue, Apr 30, 2024 at 2:51 PM Marek Behún <kabel@kernel.org> wrote:

...

> > > > > +static int omnia_get_version_hash(struct omnia_mcu *mcu, bool bootloader,
> > > > > +                                 u8 version[static OMNIA_FW_VERSION_HEX_LEN])
> > > >
> > > > Interesting format of the last parameter. Does it make any difference
> > > > to the compiler if you use u8 *version?
> > >
> > > The compiler will warn if an array with not enough space is passed as
> > > argument.
> >
> > Really?
>
> Indeed:
>
>   extern void a(char *x);
>
>   static void b(char x[static 10]) {
>       a(x);
>   }
>
>   void c(void) {
>       char x[5] = "abcd";

>       b(x);

It's not the example I was talking about. Here should be a(x).

>   }
>
> says:
>   test.c: In function ‘c’:
>   test.c:9:9: warning: ‘b’ accessing 10 bytes in a region of size 5 [-Wstringop-overflow=]
>       9 |         b(x);
>         |         ^~~~
>   test.c:9:9: note: referencing argument 1 of type ‘char[10]’
>   test.c:3:13: note: in a call to function ‘b’
>       3 | static void b(char x[static 10]) {
>         |

...

> > > > > +               omnia_info_missing_feature(dev, "feature reading");
> > > >
> > > > Tautology. Read the final message. I believe you wanted to pass just
> > > > "reading" here.
> > >
> > > No, I actually wanted it to print
> > >   Your board's MCU firmware does not support the feature reading
> > >   feature.
> > > as in the feature "feature reading" is not supported.
> > > I guess I could change it to
> > >   Your board's MCU firmware does not support the feature reading.
> > > but that would complicate the code: either I would need to add
> > > " feature" suffix to all the features[].name, or duplicate the
> > > info string from the omnia_info_missing_feature() function.
> >
> > From point of a mere user (as I am towards this driver) I consider
> > the tautology confusing.
> >
> >       ...the 'reading' feature
> >
> > may be a good compromise.
>
> I have rewritten it to use another dev_info:
>   dev_info(dev,
>            "Your board's MCU firmware does not support feature reading.\n");

OK! As long as there are no two messages in a row for the same error.
Marek Behún May 2, 2024, 7:17 p.m. UTC | #5 
On Thu, May 02, 2024 at 09:47:25PM +0300, Andy Shevchenko wrote:
> On Thu, May 2, 2024 at 9:40 PM Marek Behún <kabel@kernel.org> wrote:
> > On Tue, Apr 30, 2024 at 06:17:45PM +0300, Andy Shevchenko wrote:
> > > On Tue, Apr 30, 2024 at 04:05:07PM +0200, Marek Behún wrote:
> > > > On Tue, 30 Apr 2024 15:53:51 +0300
> > > > Andy Shevchenko <andy.shevchenko@gmail.com> wrote:
> > > > > On Tue, Apr 30, 2024 at 2:51 PM Marek Behún <kabel@kernel.org> wrote:
> 
> ...
> 
> > > > > > +static int omnia_get_version_hash(struct omnia_mcu *mcu, bool bootloader,
> > > > > > +                                 u8 version[static OMNIA_FW_VERSION_HEX_LEN])
> > > > >
> > > > > Interesting format of the last parameter. Does it make any difference
> > > > > to the compiler if you use u8 *version?
> > > >
> > > > The compiler will warn if an array with not enough space is passed as
> > > > argument.
> > >
> > > Really?
> >
> > Indeed:
> >
> >   extern void a(char *x);
> >
> >   static void b(char x[static 10]) {
> >       a(x);
> >   }
> >
> >   void c(void) {
> >       char x[5] = "abcd";
> 
> >       b(x);
> 
> It's not the example I was talking about. Here should be a(x).

Somehow I got lost. Let's return to my function, where I have
  int omnia_get_version_hash(..., u8 version[static 40]);

and then I use this function:

  u8 version[40];
  omnia_get_version_hash(..., version);

If somehow I made a mistake and declared the version array shorter:
  u8 version[20];
  omnia_get_version_hash(..., version);
I would get a warning.

So the purpose is to get warned if the compiler can prove that there is
not enough space in the destination buffer.

Marek
Marek Behún May 2, 2024, 7:19 p.m. UTC | #6 
Thanks, Ilpo, I've applied all your suggestions.
Andy Shevchenko May 3, 2024, 3:59 a.m. UTC | #7 
On Thu, May 2, 2024 at 10:18 PM Marek Behún <kabel@kernel.org> wrote:
> On Thu, May 02, 2024 at 09:47:25PM +0300, Andy Shevchenko wrote:
> > On Thu, May 2, 2024 at 9:40 PM Marek Behún <kabel@kernel.org> wrote:
> > > On Tue, Apr 30, 2024 at 06:17:45PM +0300, Andy Shevchenko wrote:
> > > > On Tue, Apr 30, 2024 at 04:05:07PM +0200, Marek Behún wrote:
> > > > > On Tue, 30 Apr 2024 15:53:51 +0300
> > > > > Andy Shevchenko <andy.shevchenko@gmail.com> wrote:
> > > > > > On Tue, Apr 30, 2024 at 2:51 PM Marek Behún <kabel@kernel.org> wrote:

...

> > > > > > > +static int omnia_get_version_hash(struct omnia_mcu *mcu, bool bootloader,
> > > > > > > +                                 u8 version[static OMNIA_FW_VERSION_HEX_LEN])
> > > > > >
> > > > > > Interesting format of the last parameter. Does it make any difference
> > > > > > to the compiler if you use u8 *version?
> > > > >
> > > > > The compiler will warn if an array with not enough space is passed as
> > > > > argument.
> > > >
> > > > Really?
> > >
> > > Indeed:
> > >
> > >   extern void a(char *x);
> > >
> > >   static void b(char x[static 10]) {
> > >       a(x);
> > >   }
> > >
> > >   void c(void) {
> > >       char x[5] = "abcd";
> >
> > >       b(x);
> >
> > It's not the example I was talking about. Here should be a(x).
>
> Somehow I got lost. Let's return to my function, where I have
>   int omnia_get_version_hash(..., u8 version[static 40]);
>
> and then I use this function:
>
>   u8 version[40];
>   omnia_get_version_hash(..., version);
>
> If somehow I made a mistake and declared the version array shorter:
>   u8 version[20];
>   omnia_get_version_hash(..., version);
> I would get a warning.

Yes. Would you get the same warning if you replace the parameter to a pointer?

> So the purpose is to get warned if the compiler can prove that there is
> not enough space in the destination buffer.
Marek Behún May 3, 2024, 6:51 a.m. UTC | #8 
On Fri, May 03, 2024 at 06:59:20AM +0300, Andy Shevchenko wrote:
> On Thu, May 2, 2024 at 10:18 PM Marek Behún <kabel@kernel.org> wrote:
> > On Thu, May 02, 2024 at 09:47:25PM +0300, Andy Shevchenko wrote:
> > > On Thu, May 2, 2024 at 9:40 PM Marek Behún <kabel@kernel.org> wrote:
> > > > On Tue, Apr 30, 2024 at 06:17:45PM +0300, Andy Shevchenko wrote:
> > > > > On Tue, Apr 30, 2024 at 04:05:07PM +0200, Marek Behún wrote:
> > > > > > On Tue, 30 Apr 2024 15:53:51 +0300
> > > > > > Andy Shevchenko <andy.shevchenko@gmail.com> wrote:
> > > > > > > On Tue, Apr 30, 2024 at 2:51 PM Marek Behún <kabel@kernel.org> wrote:
> 
> ...
> 
> > > > > > > > +static int omnia_get_version_hash(struct omnia_mcu *mcu, bool bootloader,
> > > > > > > > +                                 u8 version[static OMNIA_FW_VERSION_HEX_LEN])
> > > > > > >
> > > > > > > Interesting format of the last parameter. Does it make any difference
> > > > > > > to the compiler if you use u8 *version?
> > > > > >
> > > > > > The compiler will warn if an array with not enough space is passed as
> > > > > > argument.
> > > > >
> > > > > Really?
> > > >
> > > > Indeed:
> > > >
> > > >   extern void a(char *x);
> > > >
> > > >   static void b(char x[static 10]) {
> > > >       a(x);
> > > >   }
> > > >
> > > >   void c(void) {
> > > >       char x[5] = "abcd";
> > >
> > > >       b(x);
> > >
> > > It's not the example I was talking about. Here should be a(x).
> >
> > Somehow I got lost. Let's return to my function, where I have
> >   int omnia_get_version_hash(..., u8 version[static 40]);
> >
> > and then I use this function:
> >
> >   u8 version[40];
> >   omnia_get_version_hash(..., version);
> >
> > If somehow I made a mistake and declared the version array shorter:
> >   u8 version[20];
> >   omnia_get_version_hash(..., version);
> > I would get a warning.
> 
> Yes. Would you get the same warning if you replace the parameter to a pointer?

If you mean instead of declaring
  u8 version[20];
if I did
  u8 *version;
  omnia_get_version_hash(..., version);
then I will get a different warning:
  version is used uninitialized

And if you mean that instead of the
  char version[static 40]
in the argument list of the function I used
  char *version,
then no, GCC spits no warning.

Marek
diff mbox series

Patch

diff --git a/Documentation/ABI/testing/sysfs-bus-i2c-devices-turris-omnia-mcu b/Documentation/ABI/testing/sysfs-bus-i2c-devices-turris-omnia-mcu
new file mode 100644
index 000000000000..ff5e7cb00206
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-bus-i2c-devices-turris-omnia-mcu
@@ -0,0 +1,81 @@ 
+What:		/sys/bus/i2c/devices/<mcu_device>/board_revision
+Date:		July 2024
+KernelVersion:	6.10
+Contact:	Marek Behún <kabel@kernel.org>
+Description:	(RO) Contains board revision number.
+
+		Only available if board information is burned in the MCU (older
+		revisions have board information burned in the ATSHA204-A chip).
+
+		Format: %u.
+
+What:		/sys/bus/i2c/devices/<mcu_device>/first_mac_address
+Date:		July 2024
+KernelVersion:	6.10
+Contact:	Marek Behún <kabel@kernel.org>
+Description:	(RO) Contains device first MAC address. Each Turris Omnia is
+		allocated 3 MAC addresses. The two additional addresses are
+		computed from the first one by incrementing it.
+
+		Only available if board information is burned in the MCU (older
+		revisions have board information burned in the ATSHA204-A chip).
+
+		Format: %pM.
+
+What:		/sys/bus/i2c/devices/<mcu_device>/fw_features
+Date:		July 2024
+KernelVersion:	6.10
+Contact:	Marek Behún <kabel@kernel.org>
+Description:	(RO) Newer versions of the microcontroller firmware report the
+		features they support. These can be read from this file. If the
+		MCU firmware is too old, this file reads 0x0.
+
+		Format: 0x%x.
+
+What:		/sys/bus/i2c/devices/<mcu_device>/fw_version_hash_application
+Date:		July 2024
+KernelVersion:	6.10
+Contact:	Marek Behún <kabel@kernel.org>
+Description:	(RO) Contains the version hash (commit hash) of the application
+		part of the microcontroller firmware.
+
+		Format: %s.
+
+What:		/sys/bus/i2c/devices/<mcu_device>/fw_version_hash_bootloader
+Date:		July 2024
+KernelVersion:	6.10
+Contact:	Marek Behún <kabel@kernel.org>
+Description:	(RO) Contains the version hash (commit hash) of the bootloader
+		part of the microcontroller firmware.
+
+		Format: %s.
+
+What:		/sys/bus/i2c/devices/<mcu_device>/mcu_type
+Date:		July 2024
+KernelVersion:	6.10
+Contact:	Marek Behún <kabel@kernel.org>
+Description:	(RO) Contains the microcontroller type (STM32, GD32, MKL).
+
+		Format: %s.
+
+What:		/sys/bus/i2c/devices/<mcu_device>/reset_selector
+Date:		July 2024
+KernelVersion:	6.10
+Contact:	Marek Behún <kabel@kernel.org>
+Description:	(RO) Contains the selected factory reset level, determined by
+		how long the rear reset button was held by the user during board
+		reset.
+
+		Format: %i.
+
+What:		/sys/bus/i2c/devices/<mcu_device>/serial_number
+Date:		July 2024
+KernelVersion:	6.10
+Contact:	Marek Behún <kabel@kernel.org>
+Description:	(RO) Contains the 64 bit long board serial number in hexadecimal
+		format.
+
+		Only available if board information is burned in the MCU (older
+		revisions have board information burned in the ATSHA204-A chip).
+
+		Format: %016X.
diff --git a/MAINTAINERS b/MAINTAINERS
index 359ed2cadfc4..2aa178a9d53e 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -2139,6 +2139,7 @@  M:	Marek Behún <kabel@kernel.org>
 S:	Maintained
 W:	https://www.turris.cz/
 F:	Documentation/ABI/testing/debugfs-moxtet
+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
 F:	Documentation/devicetree/bindings/bus/moxtet.txt
@@ -2152,10 +2153,12 @@  F:	drivers/firmware/turris-mox-rwtm.c
 F:	drivers/gpio/gpio-moxtet.c
 F:	drivers/leds/leds-turris-omnia.c
 F:	drivers/mailbox/armada-37xx-rwtm-mailbox.c
+F:	drivers/platform/cznic/
 F:	drivers/watchdog/armada_37xx_wdt.c
 F:	include/dt-bindings/bus/moxtet.h
 F:	include/linux/armada-37xx-rwtm-mailbox.h
 F:	include/linux/moxtet.h
+F:	include/linux/turris-omnia-mcu-interface.h
 
 ARM/FARADAY FA526 PORT
 M:	Hans Ulli Kroll <ulli.kroll@googlemail.com>
diff --git a/drivers/platform/Kconfig b/drivers/platform/Kconfig
index 868b20361769..fef907a94001 100644
--- a/drivers/platform/Kconfig
+++ b/drivers/platform/Kconfig
@@ -7,6 +7,8 @@  source "drivers/platform/goldfish/Kconfig"
 
 source "drivers/platform/chrome/Kconfig"
 
+source "drivers/platform/cznic/Kconfig"
+
 source "drivers/platform/mellanox/Kconfig"
 
 source "drivers/platform/olpc/Kconfig"
diff --git a/drivers/platform/Makefile b/drivers/platform/Makefile
index 41640172975a..8bf189264374 100644
--- a/drivers/platform/Makefile
+++ b/drivers/platform/Makefile
@@ -10,4 +10,5 @@  obj-$(CONFIG_MIPS)		+= mips/
 obj-$(CONFIG_OLPC_EC)		+= olpc/
 obj-$(CONFIG_GOLDFISH)		+= goldfish/
 obj-$(CONFIG_CHROME_PLATFORMS)	+= chrome/
+obj-$(CONFIG_CZNIC_PLATFORMS)	+= cznic/
 obj-$(CONFIG_SURFACE_PLATFORMS)	+= surface/
diff --git a/drivers/platform/cznic/Kconfig b/drivers/platform/cznic/Kconfig
new file mode 100644
index 000000000000..f8560ff9c1af
--- /dev/null
+++ b/drivers/platform/cznic/Kconfig
@@ -0,0 +1,26 @@ 
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# For a description of the syntax of this configuration file,
+# see Documentation/kbuild/kconfig-language.rst.
+#
+
+menuconfig CZNIC_PLATFORMS
+	bool "Platform support for CZ.NIC's Turris hardware"
+	depends on MACH_ARMADA_38X || COMPILE_TEST
+	help
+	  Say Y here to be able to choose driver support for CZ.NIC's Turris
+	  devices. This option alone does not add any kernel code.
+
+if CZNIC_PLATFORMS
+
+config TURRIS_OMNIA_MCU
+	tristate "Turris Omnia MCU driver"
+	depends on MACH_ARMADA_38X || COMPILE_TEST
+	depends on I2C
+	help
+	  Say Y here to add support for the features implemented by the
+	  microcontroller on the CZ.NIC's Turris Omnia SOHO router.
+	  To compile this driver as a module, choose M here; the module will be
+	  called turris-omnia-mcu.
+
+endif # CZNIC_PLATFORMS
diff --git a/drivers/platform/cznic/Makefile b/drivers/platform/cznic/Makefile
new file mode 100644
index 000000000000..31adca73bb94
--- /dev/null
+++ b/drivers/platform/cznic/Makefile
@@ -0,0 +1,4 @@ 
+# SPDX-License-Identifier: GPL-2.0-only
+
+obj-$(CONFIG_TURRIS_OMNIA_MCU)	+= turris-omnia-mcu.o
+turris-omnia-mcu-y		:= turris-omnia-mcu-base.o
diff --git a/drivers/platform/cznic/turris-omnia-mcu-base.c b/drivers/platform/cznic/turris-omnia-mcu-base.c
new file mode 100644
index 000000000000..8893c990853a
--- /dev/null
+++ b/drivers/platform/cznic/turris-omnia-mcu-base.c
@@ -0,0 +1,376 @@ 
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * CZ.NIC's Turris Omnia MCU driver
+ *
+ * 2024 by Marek Behún <kabel@kernel.org>
+ */
+
+#include <linux/array_size.h>
+#include <linux/bits.h>
+#include <linux/device.h>
+#include <linux/hex.h>
+#include <linux/i2c.h>
+#include <linux/module.h>
+#include <linux/turris-omnia-mcu-interface.h>
+#include <linux/types.h>
+#include <linux/string.h>
+#include <linux/sysfs.h>
+
+#include "turris-omnia-mcu.h"
+
+#define OMNIA_FW_VERSION_LEN		20
+#define OMNIA_FW_VERSION_HEX_LEN	(2 * OMNIA_FW_VERSION_LEN + 1)
+#define OMNIA_BOARD_INFO_LEN		16
+
+int omnia_cmd_read(const struct i2c_client *client, u8 cmd, void *reply,
+		   unsigned int len)
+{
+	struct i2c_msg msgs[2];
+	int ret;
+
+	msgs[0].addr = client->addr;
+	msgs[0].flags = 0;
+	msgs[0].len = 1;
+	msgs[0].buf = &cmd;
+	msgs[1].addr = client->addr;
+	msgs[1].flags = I2C_M_RD;
+	msgs[1].len = len;
+	msgs[1].buf = reply;
+
+	ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
+	if (ret < 0)
+		return ret;
+	if (ret != ARRAY_SIZE(msgs))
+		return -EIO;
+
+	return 0;
+}
+
+static int omnia_get_version_hash(struct omnia_mcu *mcu, bool bootloader,
+				  u8 version[static OMNIA_FW_VERSION_HEX_LEN])
+{
+	u8 reply[OMNIA_FW_VERSION_LEN];
+	int err;
+
+	err = omnia_cmd_read(mcu->client,
+			     bootloader ? CMD_GET_FW_VERSION_BOOT
+					: CMD_GET_FW_VERSION_APP,
+			     reply, sizeof(reply));
+	if (err)
+		return err;
+
+	version[OMNIA_FW_VERSION_HEX_LEN - 1] = '\0';
+	bin2hex(version, reply, OMNIA_FW_VERSION_LEN);
+
+	return 0;
+}
+
+static ssize_t fw_version_hash_show(struct device *dev, char *buf,
+				    bool bootloader)
+{
+	struct omnia_mcu *mcu = dev_get_drvdata(dev);
+	u8 version[OMNIA_FW_VERSION_HEX_LEN];
+	int err;
+
+	err = omnia_get_version_hash(mcu, bootloader, version);
+	if (err)
+		return err;
+
+	return sysfs_emit(buf, "%s\n", version);
+}
+
+static ssize_t fw_version_hash_application_show(struct device *dev,
+						struct device_attribute *a,
+						char *buf)
+{
+	return fw_version_hash_show(dev, buf, false);
+}
+static DEVICE_ATTR_RO(fw_version_hash_application);
+
+static ssize_t fw_version_hash_bootloader_show(struct device *dev,
+					       struct device_attribute *a,
+					       char *buf)
+{
+	return fw_version_hash_show(dev, buf, true);
+}
+static DEVICE_ATTR_RO(fw_version_hash_bootloader);
+
+static ssize_t fw_features_show(struct device *dev, struct device_attribute *a,
+				char *buf)
+{
+	struct omnia_mcu *mcu = dev_get_drvdata(dev);
+
+	return sysfs_emit(buf, "0x%x\n", mcu->features);
+}
+static DEVICE_ATTR_RO(fw_features);
+
+static ssize_t mcu_type_show(struct device *dev, struct device_attribute *a,
+			     char *buf)
+{
+	struct omnia_mcu *mcu = dev_get_drvdata(dev);
+
+	return sysfs_emit(buf, "%s\n", mcu->type);
+}
+static DEVICE_ATTR_RO(mcu_type);
+
+static ssize_t reset_selector_show(struct device *dev,
+				   struct device_attribute *a, char *buf)
+{
+	int ret;
+
+	ret = omnia_cmd_read_u8(to_i2c_client(dev), CMD_GET_RESET);
+	if (ret < 0)
+		return ret;
+
+	return sysfs_emit(buf, "%d\n", ret);
+}
+static DEVICE_ATTR_RO(reset_selector);
+
+static ssize_t serial_number_show(struct device *dev,
+				  struct device_attribute *a, char *buf)
+{
+	struct omnia_mcu *mcu = dev_get_drvdata(dev);
+
+	return sysfs_emit(buf, "%016llX\n", mcu->board_serial_number);
+}
+static DEVICE_ATTR_RO(serial_number);
+
+static ssize_t first_mac_address_show(struct device *dev,
+				      struct device_attribute *a, char *buf)
+{
+	struct omnia_mcu *mcu = dev_get_drvdata(dev);
+
+	return sysfs_emit(buf, "%pM\n", mcu->board_first_mac);
+}
+static DEVICE_ATTR_RO(first_mac_address);
+
+static ssize_t board_revision_show(struct device *dev,
+				   struct device_attribute *a, char *buf)
+{
+	struct omnia_mcu *mcu = dev_get_drvdata(dev);
+
+	return sysfs_emit(buf, "%u\n", mcu->board_revision);
+}
+static DEVICE_ATTR_RO(board_revision);
+
+static struct attribute *omnia_mcu_base_attrs[] = {
+	&dev_attr_fw_version_hash_application.attr,
+	&dev_attr_fw_version_hash_bootloader.attr,
+	&dev_attr_fw_features.attr,
+	&dev_attr_mcu_type.attr,
+	&dev_attr_reset_selector.attr,
+	&dev_attr_serial_number.attr,
+	&dev_attr_first_mac_address.attr,
+	&dev_attr_board_revision.attr,
+	NULL
+};
+
+static umode_t omnia_mcu_base_attrs_visible(struct kobject *kobj,
+					    struct attribute *a, int n)
+{
+	struct device *dev = kobj_to_dev(kobj);
+	struct omnia_mcu *mcu = dev_get_drvdata(dev);
+	umode_t mode = a->mode;
+
+	if ((a == &dev_attr_serial_number.attr ||
+	     a == &dev_attr_first_mac_address.attr ||
+	     a == &dev_attr_board_revision.attr) &&
+	    !(mcu->features & FEAT_BOARD_INFO))
+		mode = 0;
+
+	return mode;
+}
+
+static const struct attribute_group omnia_mcu_base_group = {
+	.attrs = omnia_mcu_base_attrs,
+	.is_visible = omnia_mcu_base_attrs_visible,
+};
+
+static const struct attribute_group *omnia_mcu_groups[] = {
+	&omnia_mcu_base_group,
+	NULL
+};
+
+static void omnia_mcu_print_version_hash(struct omnia_mcu *mcu, bool bootloader)
+{
+	const char *type = bootloader ? "bootloader" : "application";
+	struct device *dev = &mcu->client->dev;
+	u8 version[OMNIA_FW_VERSION_HEX_LEN];
+	int err;
+
+	err = omnia_get_version_hash(mcu, bootloader, version);
+	if (err) {
+		dev_err(dev, "Cannot read MCU %s firmware version: %d\n", type,
+			err);
+		return;
+	}
+
+	dev_info(dev, "MCU %s firmware version hash: %s\n", type, version);
+}
+
+static const char *omnia_status_to_mcu_type(uint16_t status)
+{
+	switch (status & STS_MCU_TYPE_MASK) {
+	case STS_MCU_TYPE_STM32:
+		return "STM32";
+	case STS_MCU_TYPE_GD32:
+		return "GD32";
+	case STS_MCU_TYPE_MKL:
+		return "MKL";
+	default:
+		return "unknown";
+	}
+}
+
+static void omnia_info_missing_feature(struct device *dev, const char *feature)
+{
+	dev_info(dev,
+		 "Your board's MCU firmware does not support the %s feature.\n",
+		 feature);
+}
+
+static int omnia_mcu_read_features(struct omnia_mcu *mcu)
+{
+	static const struct {
+		uint16_t mask;
+		const char *name;
+	} features[] = {
+		{ FEAT_EXT_CMDS,	   "extended control and status" },
+		{ FEAT_WDT_PING,	   "watchdog pinging" },
+		{ FEAT_LED_STATE_EXT_MASK, "peripheral LED pins reading" },
+		{ FEAT_NEW_INT_API,	   "new interrupt API" },
+		{ FEAT_POWEROFF_WAKEUP,	   "poweroff and wakeup" },
+		{ FEAT_TRNG,		   "true random number generator" },
+	};
+	struct device *dev = &mcu->client->dev;
+	bool suggest_fw_upgrade = false;
+	int status;
+
+	/* status word holds MCU type, which we need below */
+	status = omnia_cmd_read_u16(mcu->client, CMD_GET_STATUS_WORD);
+	if (status < 0)
+		return status;
+
+	/* check whether MCU firmware supports the CMD_GET_FEAUTRES command */
+	if (status & STS_FEATURES_SUPPORTED) {
+		__le32 reply;
+		int ret;
+
+		/* try read 32-bit features */
+		ret = omnia_cmd_read(mcu->client, CMD_GET_FEATURES, &reply,
+				     sizeof(reply));
+		if (ret) {
+			/* try read 16-bit features */
+			ret = omnia_cmd_read_u16(mcu->client, CMD_GET_FEATURES);
+			if (ret < 0)
+				return ret;
+
+			mcu->features = ret;
+		} else {
+			mcu->features = le32_to_cpu(reply);
+
+			if (mcu->features & FEAT_FROM_BIT_16_INVALID)
+				mcu->features &= GENMASK(15, 0);
+		}
+	} else {
+		omnia_info_missing_feature(dev, "feature reading");
+		suggest_fw_upgrade = true;
+	}
+
+	mcu->type = omnia_status_to_mcu_type(status);
+	dev_info(dev, "MCU type %s%s\n", mcu->type,
+		 (mcu->features & FEAT_PERIPH_MCU) ?
+			", with peripheral resets wired" : "");
+
+	omnia_mcu_print_version_hash(mcu, true);
+
+	if (mcu->features & FEAT_BOOTLOADER)
+		dev_warn(dev,
+			 "MCU is running bootloader firmware. Was firmware upgrade interrupted?\n");
+	else
+		omnia_mcu_print_version_hash(mcu, false);
+
+	for (unsigned int i = 0; i < ARRAY_SIZE(features); i++) {
+		if (mcu->features & features[i].mask)
+			continue;
+
+		omnia_info_missing_feature(dev, features[i].name);
+		suggest_fw_upgrade = true;
+	}
+
+	if (suggest_fw_upgrade)
+		dev_info(dev,
+			 "Consider upgrading MCU firmware with the omnia-mcutool utility.\n");
+
+	return 0;
+}
+
+static int omnia_mcu_read_board_info(struct omnia_mcu *mcu)
+{
+	u8 reply[1 + OMNIA_BOARD_INFO_LEN];
+	int err;
+
+	err = omnia_cmd_read(mcu->client, CMD_BOARD_INFO_GET, reply,
+			     sizeof(reply));
+	if (err)
+		return err;
+
+	if (reply[0] != OMNIA_BOARD_INFO_LEN)
+		return -EIO;
+
+	mcu->board_serial_number = get_unaligned_le64(&reply[1]);
+	memcpy(mcu->board_first_mac, &reply[9], ETH_ALEN);
+	mcu->board_revision = reply[15];
+
+	return 0;
+}
+
+static int omnia_mcu_probe(struct i2c_client *client)
+{
+	struct device *dev = &client->dev;
+	struct omnia_mcu *mcu;
+	int err;
+
+	if (!client->irq)
+		return dev_err_probe(dev, -EINVAL, "IRQ resource not found\n");
+
+	mcu = devm_kzalloc(dev, sizeof(*mcu), GFP_KERNEL);
+	if (!mcu)
+		return -ENOMEM;
+
+	mcu->client = client;
+	i2c_set_clientdata(client, mcu);
+
+	err = omnia_mcu_read_features(mcu);
+	if (err)
+		return dev_err_probe(dev, err,
+				     "Cannot determine MCU supported features\n");
+
+	if (mcu->features & FEAT_BOARD_INFO) {
+		err = omnia_mcu_read_board_info(mcu);
+		if (err)
+			return dev_err_probe(dev, err,
+					     "Cannot read board info\n");
+	}
+
+	return 0;
+}
+
+static const struct of_device_id of_omnia_mcu_match[] = {
+	{ .compatible = "cznic,turris-omnia-mcu" },
+	{}
+};
+
+static struct i2c_driver omnia_mcu_driver = {
+	.probe		= omnia_mcu_probe,
+	.driver		= {
+		.name	= "turris-omnia-mcu",
+		.of_match_table = of_omnia_mcu_match,
+		.dev_groups = omnia_mcu_groups,
+	},
+};
+module_i2c_driver(omnia_mcu_driver);
+
+MODULE_AUTHOR("Marek Behun <kabel@kernel.org>");
+MODULE_DESCRIPTION("CZ.NIC's Turris Omnia MCU");
+MODULE_LICENSE("GPL");
diff --git a/drivers/platform/cznic/turris-omnia-mcu.h b/drivers/platform/cznic/turris-omnia-mcu.h
new file mode 100644
index 000000000000..5b21fbca8fe1
--- /dev/null
+++ b/drivers/platform/cznic/turris-omnia-mcu.h
@@ -0,0 +1,50 @@ 
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * CZ.NIC's Turris Omnia MCU driver
+ *
+ * 2024 by Marek Behún <kabel@kernel.org>
+ */
+
+#ifndef __TURRIS_OMNIA_MCU_H
+#define __TURRIS_OMNIA_MCU_H
+
+#include <linux/i2c.h>
+#include <linux/if_ether.h>
+#include <linux/types.h>
+#include <asm/byteorder.h>
+
+struct omnia_mcu {
+	struct i2c_client *client;
+	const char *type;
+	u32 features;
+
+	/* board information */
+	u64 board_serial_number;
+	u8 board_first_mac[ETH_ALEN];
+	u8 board_revision;
+};
+
+int omnia_cmd_read(const struct i2c_client *client, u8 cmd, void *reply,
+		   unsigned int len);
+
+static inline int omnia_cmd_read_u16(const struct i2c_client *client, u8 cmd)
+{
+	__le16 reply;
+	int err;
+
+	err = omnia_cmd_read(client, cmd, &reply, sizeof(reply));
+
+	return err ?: le16_to_cpu(reply);
+}
+
+static inline int omnia_cmd_read_u8(const struct i2c_client *client, u8 cmd)
+{
+	u8 reply;
+	int err;
+
+	err = omnia_cmd_read(client, cmd, &reply, sizeof(reply));
+
+	return err ?: reply;
+}
+
+#endif /* __TURRIS_OMNIA_MCU_H */
diff --git a/include/linux/turris-omnia-mcu-interface.h b/include/linux/turris-omnia-mcu-interface.h
new file mode 100644
index 000000000000..88f8490b5897
--- /dev/null
+++ b/include/linux/turris-omnia-mcu-interface.h
@@ -0,0 +1,249 @@ 
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * CZ.NIC's Turris Omnia MCU I2C interface commands definitions
+ *
+ * 2024 by Marek Behún <kabel@kernel.org>
+ */
+
+#ifndef __TURRIS_OMNIA_MCU_INTERFACE_H
+#define __TURRIS_OMNIA_MCU_INTERFACE_H
+
+#include <linux/bitfield.h>
+#include <linux/bits.h>
+
+enum omnia_commands_e {
+	CMD_GET_STATUS_WORD		= 0x01, /* slave sends status word back */
+	CMD_GENERAL_CONTROL		= 0x02,
+	CMD_LED_MODE			= 0x03, /* default/user */
+	CMD_LED_STATE			= 0x04, /* LED on/off */
+	CMD_LED_COLOR			= 0x05, /* LED number + RED + GREEN + BLUE */
+	CMD_USER_VOLTAGE		= 0x06,
+	CMD_SET_BRIGHTNESS		= 0x07,
+	CMD_GET_BRIGHTNESS		= 0x08,
+	CMD_GET_RESET			= 0x09,
+	CMD_GET_FW_VERSION_APP		= 0x0A, /* 20B git hash number */
+	CMD_SET_WATCHDOG_STATE		= 0x0B, /* 0 - disable
+						 * 1 - enable / ping
+						 * after boot watchdog is started
+						 * with 2 minutes timeout
+						 */
+
+	/* CMD_WATCHDOG_STATUS		= 0x0C, not implemented anymore */
+
+	CMD_GET_WATCHDOG_STATE		= 0x0D,
+	CMD_GET_FW_VERSION_BOOT		= 0x0E, /* 20B git hash number */
+	CMD_GET_FW_CHECKSUM		= 0x0F, /* 4B length, 4B checksum */
+
+	/* available if FEATURES_SUPPORTED bit set in status word */
+	CMD_GET_FEATURES		= 0x10,
+
+	/* available if EXT_CMD bit set in features */
+	CMD_GET_EXT_STATUS_DWORD	= 0x11,
+	CMD_EXT_CONTROL			= 0x12,
+	CMD_GET_EXT_CONTROL_STATUS	= 0x13,
+
+	/* available if NEW_INT_API bit set in features */
+	CMD_GET_INT_AND_CLEAR		= 0x14,
+	CMD_GET_INT_MASK		= 0x15,
+	CMD_SET_INT_MASK		= 0x16,
+
+	/* available if FLASHING bit set in features */
+	CMD_FLASH			= 0x19,
+
+	/* available if WDT_PING bit set in features */
+	CMD_SET_WDT_TIMEOUT		= 0x20,
+	CMD_GET_WDT_TIMELEFT		= 0x21,
+
+	/* available if POWEROFF_WAKEUP bit set in features */
+	CMD_SET_WAKEUP			= 0x22,
+	CMD_GET_UPTIME_AND_WAKEUP	= 0x23,
+	CMD_POWER_OFF			= 0x24,
+
+	/* available if USB_OVC_PROT_SETTING bit set in features */
+	CMD_SET_USB_OVC_PROT		= 0x25,
+	CMD_GET_USB_OVC_PROT		= 0x26,
+
+	/* available if TRNG bit set in features */
+	CMD_TRNG_COLLECT_ENTROPY	= 0x28,
+
+	/* available if CRYPTO bit set in features */
+	CMD_CRYPTO_GET_PUBLIC_KEY	= 0x29,
+	CMD_CRYPTO_SIGN_MESSAGE		= 0x2A,
+	CMD_CRYPTO_COLLECT_SIGNATURE	= 0x2B,
+
+	/* available if BOARD_INFO it set in features */
+	CMD_BOARD_INFO_GET		= 0x2C,
+	CMD_BOARD_INFO_BURN		= 0x2D,
+
+	/* available only at address 0x2b (led-controller) */
+	/* available only if LED_GAMMA_CORRECTION bit set in features */
+	CMD_SET_GAMMA_CORRECTION	= 0x30,
+	CMD_GET_GAMMA_CORRECTION	= 0x31,
+
+	/* available only at address 0x2b (led-controller) */
+	/* available only if PER_LED_CORRECTION bit set in features */
+	/* available only if FROM_BIT_16_INVALID bit NOT set in features */
+	CMD_SET_LED_CORRECTIONS		= 0x32,
+	CMD_GET_LED_CORRECTIONS		= 0x33,
+};
+
+enum omnia_flashing_commands_e {
+	FLASH_CMD_UNLOCK		= 0x01,
+	FLASH_CMD_SIZE_AND_CSUM		= 0x02,
+	FLASH_CMD_PROGRAM		= 0x03,
+	FLASH_CMD_RESET			= 0x04,
+};
+
+enum omnia_sts_word_e {
+	STS_MCU_TYPE_MASK			= GENMASK(1, 0),
+	STS_MCU_TYPE_STM32			= 0 << 0,
+	STS_MCU_TYPE_GD32			= 1 << 0,
+	STS_MCU_TYPE_MKL			= 2 << 0,
+	STS_FEATURES_SUPPORTED			= BIT(2),
+	STS_USER_REGULATOR_NOT_SUPPORTED	= BIT(3),
+	STS_CARD_DET				= BIT(4),
+	STS_MSATA_IND				= BIT(5),
+	STS_USB30_OVC				= BIT(6),
+	STS_USB31_OVC				= BIT(7),
+	STS_USB30_PWRON				= BIT(8),
+	STS_USB31_PWRON				= BIT(9),
+	STS_ENABLE_4V5				= BIT(10),
+	STS_BUTTON_MODE				= BIT(11),
+	STS_BUTTON_PRESSED			= BIT(12),
+	STS_BUTTON_COUNTER_MASK			= GENMASK(15, 13)
+};
+
+enum omnia_ctl_byte_e {
+	CTL_LIGHT_RST		= BIT(0),
+	CTL_HARD_RST		= BIT(1),
+	/* BIT(2) is currently reserved */
+	CTL_USB30_PWRON		= BIT(3),
+	CTL_USB31_PWRON		= BIT(4),
+	CTL_ENABLE_4V5		= BIT(5),
+	CTL_BUTTON_MODE		= BIT(6),
+	CTL_BOOTLOADER		= BIT(7)
+};
+
+enum omnia_features_e {
+	FEAT_PERIPH_MCU			= BIT(0),
+	FEAT_EXT_CMDS			= BIT(1),
+	FEAT_WDT_PING			= BIT(2),
+	FEAT_LED_STATE_EXT_MASK		= GENMASK(4, 3),
+	FEAT_LED_STATE_EXT		= 1 << 3,
+	FEAT_LED_STATE_EXT_V32		= 2 << 3,
+	FEAT_LED_GAMMA_CORRECTION	= BIT(5),
+	FEAT_NEW_INT_API		= BIT(6),
+	FEAT_BOOTLOADER			= BIT(7),
+	FEAT_FLASHING			= BIT(8),
+	FEAT_NEW_MESSAGE_API		= BIT(9),
+	FEAT_BRIGHTNESS_INT		= BIT(10),
+	FEAT_POWEROFF_WAKEUP		= BIT(11),
+	FEAT_CAN_OLD_MESSAGE_API	= BIT(12),
+	FEAT_TRNG			= BIT(13),
+	FEAT_CRYPTO			= BIT(14),
+	FEAT_BOARD_INFO			= BIT(15),
+
+	/*
+	 * Orginally the features command replied only 16 bits. If more were
+	 * read, either the I2C transaction failed or 0xff bytes were sent.
+	 * Therefore to consider bits 16 - 31 valid, one bit (20) was reserved
+	 * to be zero.
+	 */
+
+	/* Bits 16 - 19 correspond to bits 0 - 3 of status word */
+	FEAT_MCU_TYPE_MASK		= GENMASK(17, 16),
+	FEAT_MCU_TYPE_STM32		= 0 << 16,
+	FEAT_MCU_TYPE_GD32		= 1 << 16,
+	FEAT_MCU_TYPE_MKL		= 2 << 16,
+	FEAT_FEATURES_SUPPORTED		= BIT(18),
+	FEAT_USER_REGULATOR_NOT_SUPPORTED = BIT(19),
+
+	/* must not be set */
+	FEAT_FROM_BIT_16_INVALID	= BIT(20),
+
+	FEAT_PER_LED_CORRECTION		= BIT(21),
+	FEAT_USB_OVC_PROT_SETTING	= BIT(22),
+};
+
+enum omnia_ext_sts_dword_e {
+	EXT_STS_SFP_nDET		= BIT(0),
+	EXT_STS_LED_STATES_MASK		= GENMASK(31, 12),
+	EXT_STS_WLAN0_MSATA_LED		= BIT(12),
+	EXT_STS_WLAN1_LED		= BIT(13),
+	EXT_STS_WLAN2_LED		= BIT(14),
+	EXT_STS_WPAN0_LED		= BIT(15),
+	EXT_STS_WPAN1_LED		= BIT(16),
+	EXT_STS_WPAN2_LED		= BIT(17),
+	EXT_STS_WAN_LED0		= BIT(18),
+	EXT_STS_WAN_LED1		= BIT(19),
+	EXT_STS_LAN0_LED0		= BIT(20),
+	EXT_STS_LAN0_LED1		= BIT(21),
+	EXT_STS_LAN1_LED0		= BIT(22),
+	EXT_STS_LAN1_LED1		= BIT(23),
+	EXT_STS_LAN2_LED0		= BIT(24),
+	EXT_STS_LAN2_LED1		= BIT(25),
+	EXT_STS_LAN3_LED0		= BIT(26),
+	EXT_STS_LAN3_LED1		= BIT(27),
+	EXT_STS_LAN4_LED0		= BIT(28),
+	EXT_STS_LAN4_LED1		= BIT(29),
+	EXT_STS_LAN5_LED0		= BIT(30),
+	EXT_STS_LAN5_LED1		= BIT(31),
+};
+
+enum omnia_ext_ctl_e {
+	EXT_CTL_nRES_MMC		= BIT(0),
+	EXT_CTL_nRES_LAN		= BIT(1),
+	EXT_CTL_nRES_PHY		= BIT(2),
+	EXT_CTL_nPERST0			= BIT(3),
+	EXT_CTL_nPERST1			= BIT(4),
+	EXT_CTL_nPERST2			= BIT(5),
+	EXT_CTL_PHY_SFP			= BIT(6),
+	EXT_CTL_PHY_SFP_AUTO		= BIT(7),
+	EXT_CTL_nVHV_CTRL		= BIT(8),
+};
+
+enum omnia_int_e {
+	INT_CARD_DET		= BIT(0),
+	INT_MSATA_IND		= BIT(1),
+	INT_USB30_OVC		= BIT(2),
+	INT_USB31_OVC		= BIT(3),
+	INT_BUTTON_PRESSED	= BIT(4),
+	INT_SFP_nDET		= BIT(5),
+	INT_BRIGHTNESS_CHANGED	= BIT(6),
+	INT_TRNG		= BIT(7),
+	INT_MESSAGE_SIGNED	= BIT(8),
+
+	INT_LED_STATES_MASK	= GENMASK(31, 12),
+	INT_WLAN0_MSATA_LED	= BIT(12),
+	INT_WLAN1_LED		= BIT(13),
+	INT_WLAN2_LED		= BIT(14),
+	INT_WPAN0_LED		= BIT(15),
+	INT_WPAN1_LED		= BIT(16),
+	INT_WPAN2_LED		= BIT(17),
+	INT_WAN_LED0		= BIT(18),
+	INT_WAN_LED1		= BIT(19),
+	INT_LAN0_LED0		= BIT(20),
+	INT_LAN0_LED1		= BIT(21),
+	INT_LAN1_LED0		= BIT(22),
+	INT_LAN1_LED1		= BIT(23),
+	INT_LAN2_LED0		= BIT(24),
+	INT_LAN2_LED1		= BIT(25),
+	INT_LAN3_LED0		= BIT(26),
+	INT_LAN3_LED1		= BIT(27),
+	INT_LAN4_LED0		= BIT(28),
+	INT_LAN4_LED1		= BIT(29),
+	INT_LAN5_LED0		= BIT(30),
+	INT_LAN5_LED1		= BIT(31),
+};
+
+enum omnia_cmd_poweroff_e {
+	CMD_POWER_OFF_POWERON_BUTTON	= BIT(0),
+	CMD_POWER_OFF_MAGIC		= 0xdead,
+};
+
+enum cmd_usb_ovc_prot_e {
+	CMD_xET_USB_OVC_PROT_PORT_MASK	= GENMASK(3, 0),
+	CMD_xET_USB_OVC_PROT_ENABLE	= BIT(4),
+};
+
+#endif /* __TURRIS_OMNIA_MCU_INTERFACE_H */