diff mbox series

watchdog: Add driver for Intel OC WDT

Message ID 20250311-ivo-intel_oc_wdt-v1-1-fd470460d9f5@siemens.com
State Superseded
Headers show
Series watchdog: Add driver for Intel OC WDT | expand

Commit Message

Diogo Ivo March 11, 2025, 1:18 p.m. UTC 
Add a driver for the Intel Over-Clocking Watchdog found in Intel
Platform Controller (PCH) chipsets. This watchdog is controlled
via a simple single-register interface and would otherwise be
standard except for the presence of a LOCK bit that can only be
set once per power cycle, needing extra handling around it.

Signed-off-by: Diogo Ivo <diogo.ivo@siemens.com>
---
 drivers/acpi/acpi_pnp.c         |   2 +
 drivers/watchdog/Kconfig        |  11 ++
 drivers/watchdog/Makefile       |   1 +
 drivers/watchdog/intel_oc_wdt.c | 235 ++++++++++++++++++++++++++++++++++++++++
 4 files changed, 249 insertions(+)


---
base-commit: 4d872d51bc9d7b899c1f61534e3dbde72613f627
change-id: 20250227-ivo-intel_oc_wdt-7a483a4d6a04

Best regards,

Comments

Guenter Roeck March 11, 2025, 2:10 p.m. UTC | #1 
On 3/11/25 06:18, Diogo Ivo wrote:
> Add a driver for the Intel Over-Clocking Watchdog found in Intel
> Platform Controller (PCH) chipsets. This watchdog is controlled
> via a simple single-register interface and would otherwise be
> standard except for the presence of a LOCK bit that can only be
> set once per power cycle, needing extra handling around it.
> 
> Signed-off-by: Diogo Ivo <diogo.ivo@siemens.com>
> ---
>   drivers/acpi/acpi_pnp.c         |   2 +
>   drivers/watchdog/Kconfig        |  11 ++
>   drivers/watchdog/Makefile       |   1 +
>   drivers/watchdog/intel_oc_wdt.c | 235 ++++++++++++++++++++++++++++++++++++++++
>   4 files changed, 249 insertions(+)
> 
> diff --git a/drivers/acpi/acpi_pnp.c b/drivers/acpi/acpi_pnp.c
> index 01abf26764b00c86f938dea2ed138424f041f880..3f5a1840f573303c71f5d579e32963a5b29d2587 100644
> --- a/drivers/acpi/acpi_pnp.c
> +++ b/drivers/acpi/acpi_pnp.c
> @@ -355,8 +355,10 @@ static bool acpi_pnp_match(const char *idstr, const struct acpi_device_id **matc
>    * device represented by it.
>    */
>   static const struct acpi_device_id acpi_nonpnp_device_ids[] = {
> +	{"INT3F0D"},
>   	{"INTC1080"},
>   	{"INTC1081"},
> +	{"INTC1099"},
>   	{""},
>   };

This needs to be a separate patch.

>   
> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
> index f81705f8539aa0b12d156a86aae521aa40b4527d..16e6df441bb344c0f91b40bd76b6322ad3016e72 100644
> --- a/drivers/watchdog/Kconfig
> +++ b/drivers/watchdog/Kconfig
> @@ -1350,6 +1350,17 @@ config INTEL_MID_WATCHDOG
>   
>   	  To compile this driver as a module, choose M here.
>   
> +config INTEL_OC_WATCHDOG
> +	tristate "Intel OC Watchdog"
> +	depends on X86 && ACPI
> +	select WATCHDOG_CORE
> +	help
> +	  Hardware driver for Intel Over-Clocking watchdog present in
> +	  Platform Controller Hub (PCH) chipsets.
> +
> +	  To compile this driver as a module, choose M here: the
> +	  module will be called intel_oc_wdt.
> +
>   config ITCO_WDT
>   	tristate "Intel TCO Timer/Watchdog"
>   	depends on X86 && PCI
> diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
> index 8411626fa162268e8ccd06349f7193b15a9d281a..3a13f3e80a0f460b99b4f1592fcf17cc6428876b 100644
> --- a/drivers/watchdog/Makefile
> +++ b/drivers/watchdog/Makefile
> @@ -149,6 +149,7 @@ obj-$(CONFIG_W83977F_WDT) += w83977f_wdt.o
>   obj-$(CONFIG_MACHZ_WDT) += machzwd.o
>   obj-$(CONFIG_SBC_EPX_C3_WATCHDOG) += sbc_epx_c3.o
>   obj-$(CONFIG_INTEL_MID_WATCHDOG) += intel-mid_wdt.o
> +obj-$(CONFIG_INTEL_OC_WATCHDOG) += intel_oc_wdt.o
>   obj-$(CONFIG_INTEL_MEI_WDT) += mei_wdt.o
>   obj-$(CONFIG_NI903X_WDT) += ni903x_wdt.o
>   obj-$(CONFIG_NIC7018_WDT) += nic7018_wdt.o
> diff --git a/drivers/watchdog/intel_oc_wdt.c b/drivers/watchdog/intel_oc_wdt.c
> new file mode 100644
> index 0000000000000000000000000000000000000000..0a2df3440024090f7e342fe7da895a7930ac09b2
> --- /dev/null
> +++ b/drivers/watchdog/intel_oc_wdt.c
> @@ -0,0 +1,235 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Intel OC Watchdog driver
> + *
> + * Copyright (C) 2025, Siemens SA
> + * Author: Diogo Ivo <diogo.ivo@siemens.com>
> + */
> +
> +#define DRV_NAME	"intel_oc_wdt"
> +
> +#include <linux/acpi.h>
> +#include <linux/bits.h>
> +#include <linux/io.h>
> +#include <linux/module.h>
> +#include <linux/moduleparam.h>
> +#include <linux/platform_device.h>
> +#include <linux/watchdog.h>
> +
> +#define INTEL_OC_WDT_TOV		GENMASK(9, 0)
> +#define INTEL_OC_WDT_MIN_TOV		1
> +#define INTEL_OC_WDT_MAX_TOV		1024
> +
> +/*
> + * One-time writable lock bit. If set forbids
> + * modification of itself, _TOV and _EN until
> + * next reboot.
> + */
> +#define INTEL_OC_WDT_CTL_LCK		BIT(12)
> +
> +#define INTEL_OC_WDT_EN			BIT(14)
> +#define INTEL_OC_WDT_NO_ICCSURV_STS	BIT(24)
> +#define INTEL_OC_WDT_ICCSURV_STS	BIT(25)
> +#define INTEL_OC_WDT_RLD		BIT(31)
> +
> +#define INTEL_OC_WDT_STS_BITS (INTEL_OC_WDT_NO_ICCSURV_STS | \
> +			       INTEL_OC_WDT_ICCSURV_STS)
> +
> +#define INTEL_OC_WDT_CTRL_REG(wdt)	((wdt)->ctrl_res->start)
> +
> +struct intel_oc_wdt {
> +	struct watchdog_device wdd;
> +	struct resource *ctrl_res;
> +	bool locked;
> +};
> +
> +#define WDT_HEARTBEAT			60
> +static int heartbeat = WDT_HEARTBEAT;

Normally this is set to 0 and the default timeout is initialized together
with min_timeout and max_timeout. This lets the watchdog core override it
with devicetree data (if that is available).

> +module_param(heartbeat, uint, 0);
> +MODULE_PARM_DESC(heartbeat, "Watchdog heartbeats in seconds. (default="
> +		 __MODULE_STRING(WDT_HEARTBEAT) ")");
> +
> +static bool nowayout = WATCHDOG_NOWAYOUT;
> +module_param(nowayout, bool, 0);
> +MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
> +		 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
> +
> +static int intel_oc_wdt_start(struct watchdog_device *wdd)
> +{
> +	struct intel_oc_wdt *oc_wdt = watchdog_get_drvdata(wdd);
> +
> +	if (oc_wdt->locked)
> +		return 0;
> +
> +	outl(inl(INTEL_OC_WDT_CTRL_REG(oc_wdt)) | INTEL_OC_WDT_EN,
> +	     INTEL_OC_WDT_CTRL_REG(oc_wdt));
> +
> +	return 0;
> +}
> +
> +static int intel_oc_wdt_stop(struct watchdog_device *wdd)
> +{
> +	struct intel_oc_wdt *oc_wdt = watchdog_get_drvdata(wdd);
> +
> +	outl(inl(INTEL_OC_WDT_CTRL_REG(oc_wdt)) & ~INTEL_OC_WDT_EN,
> +	     INTEL_OC_WDT_CTRL_REG(oc_wdt));
> +
> +	return 0;
> +}
> +
> +static int intel_oc_wdt_ping(struct watchdog_device *wdd)
> +{
> +	struct intel_oc_wdt *oc_wdt = watchdog_get_drvdata(wdd);
> +
> +	outl(inl(INTEL_OC_WDT_CTRL_REG(oc_wdt)) | INTEL_OC_WDT_RLD,
> +	     INTEL_OC_WDT_CTRL_REG(oc_wdt));
> +
> +	return 0;
> +}
> +
> +static int intel_oc_wdt_set_timeout(struct watchdog_device *wdd,
> +				    unsigned int t)
> +{
> +	struct intel_oc_wdt *oc_wdt = watchdog_get_drvdata(wdd);
> +
> +	outl((inl(INTEL_OC_WDT_CTRL_REG(oc_wdt)) & ~INTEL_OC_WDT_TOV) | (t - 1),
> +	     INTEL_OC_WDT_CTRL_REG(oc_wdt));
> +
> +	wdd->timeout = t;
> +
> +	return 0;
> +}
> +
> +static const struct watchdog_info intel_oc_wdt_info = {
> +	.options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,
> +	.identity = DRV_NAME,
> +};
> +
> +static const struct watchdog_ops intel_oc_wdt_ops = {
> +	.owner = THIS_MODULE,
> +	.start = intel_oc_wdt_start,
> +	.stop = intel_oc_wdt_stop,
> +	.ping = intel_oc_wdt_ping,
> +	.set_timeout = intel_oc_wdt_set_timeout,
> +};
> +
> +static int intel_oc_wdt_setup(struct intel_oc_wdt *oc_wdt)
> +{
> +	struct watchdog_info *info;
> +	unsigned long val;
> +
> +	val = inl(INTEL_OC_WDT_CTRL_REG(oc_wdt));
> +
> +	if (val & INTEL_OC_WDT_STS_BITS)
> +		oc_wdt->wdd.bootstatus |= WDIOF_CARDRESET;
> +
> +	oc_wdt->locked = !!(val & INTEL_OC_WDT_CTL_LCK);
> +
> +	if (val & INTEL_OC_WDT_EN) {
> +		/*
> +		 * No need to issue a ping here to "commit" the new timeout
> +		 * value to hardware as the watchdog core schedules one
> +		 * immediately when registering the watchdog.
> +		 */
> +		set_bit(WDOG_HW_RUNNING, &oc_wdt->wdd.status);
> +
> +		if (oc_wdt->locked) {
> +			info = (struct watchdog_info *)&intel_oc_wdt_info;
> +			/*
> +			 * Set nowayout unconditionally as we cannot stop
> +			 * the watchdog and read the current timeout.
> +			 */

But the timeout is read below ? Do you mean "change the current timeout" ?

> +			nowayout = true;
> +
> +			oc_wdt->wdd.timeout = (val & INTEL_OC_WDT_TOV) + 1;
> +			info->options &= ~WDIOF_SETTIMEOUT;
> +
> +			dev_info(oc_wdt->wdd.parent,
> +				 "Register access locked, heartbeat fixed at: %u s\n",
> +				 oc_wdt->wdd.timeout);
> +		}
> +	} else if (oc_wdt->locked) {
> +		/*
> +		 * In case the watchdog is disabled and locked there
> +		 * is nothing we can do with it so just fail probing.
> +		 */
> +		return -EACCES;
> +	}
> +
> +	val &= ~INTEL_OC_WDT_TOV;
> +	outl(val | (oc_wdt->wdd.timeout - 1), INTEL_OC_WDT_CTRL_REG(oc_wdt));
> +
> +	return 0;
> +}
> +
> +static int intel_oc_wdt_probe(struct platform_device *pdev)
> +{
> +	struct device *dev = &pdev->dev;
> +	struct intel_oc_wdt *oc_wdt;
> +	struct watchdog_device *wdd;
> +	int ret;
> +
> +	oc_wdt = devm_kzalloc(&pdev->dev, sizeof(*oc_wdt), GFP_KERNEL);
> +	if (!oc_wdt)
> +		return -ENOMEM;
> +
> +	oc_wdt->ctrl_res = platform_get_resource(pdev, IORESOURCE_IO, 0);
> +	if (!oc_wdt->ctrl_res) {
> +		dev_err(&pdev->dev, "missing I/O resource\n");
> +		return -ENODEV;
> +	}
> +
> +	if (!devm_request_region(&pdev->dev, oc_wdt->ctrl_res->start,
> +				 resource_size(oc_wdt->ctrl_res), pdev->name)) {
> +		dev_err(dev, "I/O address 0x%04llx already in use, device disabled\n",
> +		       (u64)(oc_wdt->ctrl_res->start));

Use %pa or %pR/%pr, and watch out for multi-line alignment.

Guenter
Guenter Roeck March 11, 2025, 4:06 p.m. UTC | #2 
On 3/11/25 07:59, Diogo Ivo wrote:
> Hi Guenter, thanks for the quick review!
> 
> On 3/11/25 2:10 PM, Guenter Roeck wrote:
>> On 3/11/25 06:18, Diogo Ivo wrote:
>>> Add a driver for the Intel Over-Clocking Watchdog found in Intel
>>> Platform Controller (PCH) chipsets. This watchdog is controlled
>>> via a simple single-register interface and would otherwise be
>>> standard except for the presence of a LOCK bit that can only be
>>> set once per power cycle, needing extra handling around it.
>>>
>>> Signed-off-by: Diogo Ivo <diogo.ivo@siemens.com>
>>> ---
>>>   drivers/acpi/acpi_pnp.c         |   2 +
>>>   drivers/watchdog/Kconfig        |  11 ++
>>>   drivers/watchdog/Makefile       |   1 +
>>>   drivers/watchdog/intel_oc_wdt.c | 235 ++++++++++++++++++++++++++++++ ++++++++++
>>>   4 files changed, 249 insertions(+)
>>>
>>> diff --git a/drivers/acpi/acpi_pnp.c b/drivers/acpi/acpi_pnp.c
>>> index 01abf26764b00c86f938dea2ed138424f041f880..3f5a1840f573303c71f5d579e32963a5b29d2587 100644
>>> --- a/drivers/acpi/acpi_pnp.c
>>> +++ b/drivers/acpi/acpi_pnp.c
>>> @@ -355,8 +355,10 @@ static bool acpi_pnp_match(const char *idstr, const struct acpi_device_id **matc
>>>    * device represented by it.
>>>    */
>>>   static const struct acpi_device_id acpi_nonpnp_device_ids[] = {
>>> +    {"INT3F0D"},
>>>       {"INTC1080"},
>>>       {"INTC1081"},
>>> +    {"INTC1099"},
>>>       {""},
>>>   };
>>
>> This needs to be a separate patch.
> 
> I will split it for v2.
> 
>>> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
>>> index f81705f8539aa0b12d156a86aae521aa40b4527d..16e6df441bb344c0f91b40bd76b6322ad3016e72 100644
>>> --- a/drivers/watchdog/Kconfig
>>> +++ b/drivers/watchdog/Kconfig
>>> @@ -1350,6 +1350,17 @@ config INTEL_MID_WATCHDOG
>>>         To compile this driver as a module, choose M here.
>>> +config INTEL_OC_WATCHDOG
>>> +    tristate "Intel OC Watchdog"
>>> +    depends on X86 && ACPI
>>> +    select WATCHDOG_CORE
>>> +    help
>>> +      Hardware driver for Intel Over-Clocking watchdog present in
>>> +      Platform Controller Hub (PCH) chipsets.
>>> +
>>> +      To compile this driver as a module, choose M here: the
>>> +      module will be called intel_oc_wdt.
>>> +
>>>   config ITCO_WDT
>>>       tristate "Intel TCO Timer/Watchdog"
>>>       depends on X86 && PCI
>>> diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
>>> index 8411626fa162268e8ccd06349f7193b15a9d281a..3a13f3e80a0f460b99b4f1592fcf17cc6428876b 100644
>>> --- a/drivers/watchdog/Makefile
>>> +++ b/drivers/watchdog/Makefile
>>> @@ -149,6 +149,7 @@ obj-$(CONFIG_W83977F_WDT) += w83977f_wdt.o
>>>   obj-$(CONFIG_MACHZ_WDT) += machzwd.o
>>>   obj-$(CONFIG_SBC_EPX_C3_WATCHDOG) += sbc_epx_c3.o
>>>   obj-$(CONFIG_INTEL_MID_WATCHDOG) += intel-mid_wdt.o
>>> +obj-$(CONFIG_INTEL_OC_WATCHDOG) += intel_oc_wdt.o
>>>   obj-$(CONFIG_INTEL_MEI_WDT) += mei_wdt.o
>>>   obj-$(CONFIG_NI903X_WDT) += ni903x_wdt.o
>>>   obj-$(CONFIG_NIC7018_WDT) += nic7018_wdt.o
>>> diff --git a/drivers/watchdog/intel_oc_wdt.c b/drivers/watchdog/ intel_oc_wdt.c
>>> new file mode 100644
>>> index 0000000000000000000000000000000000000000..0a2df3440024090f7e342fe7da895a7930ac09b2
>>> --- /dev/null
>>> +++ b/drivers/watchdog/intel_oc_wdt.c
>>> @@ -0,0 +1,235 @@
>>> +// SPDX-License-Identifier: GPL-2.0
>>> +/*
>>> + * Intel OC Watchdog driver
>>> + *
>>> + * Copyright (C) 2025, Siemens SA
>>> + * Author: Diogo Ivo <diogo.ivo@siemens.com>
>>> + */
>>> +
>>> +#define DRV_NAME    "intel_oc_wdt"
>>> +
>>> +#include <linux/acpi.h>
>>> +#include <linux/bits.h>
>>> +#include <linux/io.h>
>>> +#include <linux/module.h>
>>> +#include <linux/moduleparam.h>
>>> +#include <linux/platform_device.h>
>>> +#include <linux/watchdog.h>
>>> +
>>> +#define INTEL_OC_WDT_TOV        GENMASK(9, 0)
>>> +#define INTEL_OC_WDT_MIN_TOV        1
>>> +#define INTEL_OC_WDT_MAX_TOV        1024
>>> +
>>> +/*
>>> + * One-time writable lock bit. If set forbids
>>> + * modification of itself, _TOV and _EN until
>>> + * next reboot.
>>> + */
>>> +#define INTEL_OC_WDT_CTL_LCK        BIT(12)
>>> +
>>> +#define INTEL_OC_WDT_EN            BIT(14)
>>> +#define INTEL_OC_WDT_NO_ICCSURV_STS    BIT(24)
>>> +#define INTEL_OC_WDT_ICCSURV_STS    BIT(25)
>>> +#define INTEL_OC_WDT_RLD        BIT(31)
>>> +
>>> +#define INTEL_OC_WDT_STS_BITS (INTEL_OC_WDT_NO_ICCSURV_STS | \
>>> +                   INTEL_OC_WDT_ICCSURV_STS)
>>> +
>>> +#define INTEL_OC_WDT_CTRL_REG(wdt)    ((wdt)->ctrl_res->start)
>>> +
>>> +struct intel_oc_wdt {
>>> +    struct watchdog_device wdd;
>>> +    struct resource *ctrl_res;
>>> +    bool locked;
>>> +};
>>> +
>>> +#define WDT_HEARTBEAT            60
>>> +static int heartbeat = WDT_HEARTBEAT;
>>
>> Normally this is set to 0 and the default timeout is initialized together
>> with min_timeout and max_timeout. This lets the watchdog core override it
>> with devicetree data (if that is available).
> 
> Ok, thank you for the insight. I will address this for v2.
> It is unlikely that this driver will have devicetree data but it's
> better to follow best practice.
> 

I just submitted a patch to have the watchdog core also look into firmware data,
which would include data provided by ACPI.

>>> +module_param(heartbeat, uint, 0);
>>> +MODULE_PARM_DESC(heartbeat, "Watchdog heartbeats in seconds. (default="
>>> +         __MODULE_STRING(WDT_HEARTBEAT) ")");
>>> +
>>> +static bool nowayout = WATCHDOG_NOWAYOUT;
>>> +module_param(nowayout, bool, 0);
>>> +MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
>>> +         __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
>>> +
>>> +static int intel_oc_wdt_start(struct watchdog_device *wdd)
>>> +{
>>> +    struct intel_oc_wdt *oc_wdt = watchdog_get_drvdata(wdd);
>>> +
>>> +    if (oc_wdt->locked)
>>> +        return 0;
>>> +
>>> +    outl(inl(INTEL_OC_WDT_CTRL_REG(oc_wdt)) | INTEL_OC_WDT_EN,
>>> +         INTEL_OC_WDT_CTRL_REG(oc_wdt));
>>> +
>>> +    return 0;
>>> +}
>>> +
>>> +static int intel_oc_wdt_stop(struct watchdog_device *wdd)
>>> +{
>>> +    struct intel_oc_wdt *oc_wdt = watchdog_get_drvdata(wdd);
>>> +
>>> +    outl(inl(INTEL_OC_WDT_CTRL_REG(oc_wdt)) & ~INTEL_OC_WDT_EN,
>>> +         INTEL_OC_WDT_CTRL_REG(oc_wdt));
>>> +
>>> +    return 0;
>>> +}
>>> +
>>> +static int intel_oc_wdt_ping(struct watchdog_device *wdd)
>>> +{
>>> +    struct intel_oc_wdt *oc_wdt = watchdog_get_drvdata(wdd);
>>> +
>>> +    outl(inl(INTEL_OC_WDT_CTRL_REG(oc_wdt)) | INTEL_OC_WDT_RLD,
>>> +         INTEL_OC_WDT_CTRL_REG(oc_wdt));
>>> +
>>> +    return 0;
>>> +}
>>> +
>>> +static int intel_oc_wdt_set_timeout(struct watchdog_device *wdd,
>>> +                    unsigned int t)
>>> +{
>>> +    struct intel_oc_wdt *oc_wdt = watchdog_get_drvdata(wdd);
>>> +
>>> +    outl((inl(INTEL_OC_WDT_CTRL_REG(oc_wdt)) & ~INTEL_OC_WDT_TOV) | (t - 1),
>>> +         INTEL_OC_WDT_CTRL_REG(oc_wdt));
>>> +
>>> +    wdd->timeout = t;
>>> +
>>> +    return 0;
>>> +}
>>> +
>>> +static const struct watchdog_info intel_oc_wdt_info = {
>>> +    .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,
>>> +    .identity = DRV_NAME,
>>> +};
>>> +
>>> +static const struct watchdog_ops intel_oc_wdt_ops = {
>>> +    .owner = THIS_MODULE,
>>> +    .start = intel_oc_wdt_start,
>>> +    .stop = intel_oc_wdt_stop,
>>> +    .ping = intel_oc_wdt_ping,
>>> +    .set_timeout = intel_oc_wdt_set_timeout,
>>> +};
>>> +
>>> +static int intel_oc_wdt_setup(struct intel_oc_wdt *oc_wdt)
>>> +{
>>> +    struct watchdog_info *info;
>>> +    unsigned long val;
>>> +
>>> +    val = inl(INTEL_OC_WDT_CTRL_REG(oc_wdt));
>>> +
>>> +    if (val & INTEL_OC_WDT_STS_BITS)
>>> +        oc_wdt->wdd.bootstatus |= WDIOF_CARDRESET;
>>> +
>>> +    oc_wdt->locked = !!(val & INTEL_OC_WDT_CTL_LCK);
>>> +
>>> +    if (val & INTEL_OC_WDT_EN) {
>>> +        /*
>>> +         * No need to issue a ping here to "commit" the new timeout
>>> +         * value to hardware as the watchdog core schedules one
>>> +         * immediately when registering the watchdog.
>>> +         */
>>> +        set_bit(WDOG_HW_RUNNING, &oc_wdt->wdd.status);
>>> +
>>> +        if (oc_wdt->locked) {
>>> +            info = (struct watchdog_info *)&intel_oc_wdt_info;
>>> +            /*
>>> +             * Set nowayout unconditionally as we cannot stop
>>> +             * the watchdog and read the current timeout.
>>> +             */
>>
>> But the timeout is read below ? Do you mean "change the current timeout" ?
> 
> In this case where the BIOS both enabled the watchdog and set the LOCK
> bit we cannot change the timeout anymore, meaning that we have to read
> the value currently in the register and pass it to the watchdog core,
> which is what is done below.
> 
Yes, but the comment says " we cannot stop the watchdog and _read_ the
current timeout" (emphasis added), suggesting that the current timeout
can not be _read_ if locked is true.

>>> +            nowayout = true;
>>> +
>>> +            oc_wdt->wdd.timeout = (val & INTEL_OC_WDT_TOV) + 1;

However, this code does read the timeout even if locked is set. That
suggests that it is not possible to _change_ the timeout if locked is set,
but that it is possible to read the current timeout.

Guenter
Krzysztof Kozlowski March 12, 2025, 8:50 a.m. UTC | #3 
On 11/03/2025 14:18, Diogo Ivo wrote:
> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
> index f81705f8539aa0b12d156a86aae521aa40b4527d..16e6df441bb344c0f91b40bd76b6322ad3016e72 100644
> --- a/drivers/watchdog/Kconfig
> +++ b/drivers/watchdog/Kconfig
> @@ -1350,6 +1350,17 @@ config INTEL_MID_WATCHDOG
>  
>  	  To compile this driver as a module, choose M here.
>  
> +config INTEL_OC_WATCHDOG
> +	tristate "Intel OC Watchdog"
> +	depends on X86 && ACPI

Why can't this be compile tested?

...

> +static const struct acpi_device_id intel_oc_wdt_match[] = {
> +	{ "INT3F0D" },
> +	{ "INTC1099" },
> +	{ },
> +};
> +MODULE_DEVICE_TABLE(acpi, intel_oc_wdt_match);
> +
> +static struct platform_driver intel_oc_wdt_platform_driver = {
> +	.driver = {
> +		.name = DRV_NAME,
> +		.acpi_match_table = ACPI_PTR(intel_oc_wdt_match),

Drop ACPI_PTR, causes warnigns and is not really beneficial.

> +	},
> +	.probe = intel_oc_wdt_probe,
> +};
> +
> +module_platform_driver(intel_oc_wdt_platform_driver);
> +
> +MODULE_AUTHOR("Diogo Ivo <diogo.ivo@siemens.com>");
> +MODULE_LICENSE("GPL");
> +MODULE_DESCRIPTION("Intel OC Watchdog driver");
> +MODULE_ALIAS("platform:" DRV_NAME);

Drop alias, you have match table.


Best regards,
Krzysztof
Diogo Ivo March 12, 2025, 3:38 p.m. UTC | #4 
Hi Krzysztof, thanks for the review.

On 3/12/25 8:50 AM, Krzysztof Kozlowski wrote:
> On 11/03/2025 14:18, Diogo Ivo wrote:
>> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
>> index f81705f8539aa0b12d156a86aae521aa40b4527d..16e6df441bb344c0f91b40bd76b6322ad3016e72 100644
>> --- a/drivers/watchdog/Kconfig
>> +++ b/drivers/watchdog/Kconfig
>> @@ -1350,6 +1350,17 @@ config INTEL_MID_WATCHDOG
>>   
>>   	  To compile this driver as a module, choose M here.
>>   
>> +config INTEL_OC_WATCHDOG
>> +	tristate "Intel OC Watchdog"
>> +	depends on X86 && ACPI
> 
> Why can't this be compile tested?

I'll add it in v2 as well as HAS_IOPORT.

>> +static const struct acpi_device_id intel_oc_wdt_match[] = {
>> +	{ "INT3F0D" },
>> +	{ "INTC1099" },
>> +	{ },
>> +};
>> +MODULE_DEVICE_TABLE(acpi, intel_oc_wdt_match);
>> +
>> +static struct platform_driver intel_oc_wdt_platform_driver = {
>> +	.driver = {
>> +		.name = DRV_NAME,
>> +		.acpi_match_table = ACPI_PTR(intel_oc_wdt_match),
> 
> Drop ACPI_PTR, causes warnigns and is not really beneficial.

I'll drop it in v2.

>> +	},
>> +	.probe = intel_oc_wdt_probe,
>> +};
>> +
>> +module_platform_driver(intel_oc_wdt_platform_driver);
>> +
>> +MODULE_AUTHOR("Diogo Ivo <diogo.ivo@siemens.com>");
>> +MODULE_LICENSE("GPL");
>> +MODULE_DESCRIPTION("Intel OC Watchdog driver");
>> +MODULE_ALIAS("platform:" DRV_NAME);
> 
> Drop alias, you have match table.

I'll drop it in v2.

> Best regards,
> Krzysztof

Best regards,
Diogo
diff mbox series

Patch

diff --git a/drivers/acpi/acpi_pnp.c b/drivers/acpi/acpi_pnp.c
index 01abf26764b00c86f938dea2ed138424f041f880..3f5a1840f573303c71f5d579e32963a5b29d2587 100644
--- a/drivers/acpi/acpi_pnp.c
+++ b/drivers/acpi/acpi_pnp.c
@@ -355,8 +355,10 @@  static bool acpi_pnp_match(const char *idstr, const struct acpi_device_id **matc
  * device represented by it.
  */
 static const struct acpi_device_id acpi_nonpnp_device_ids[] = {
+	{"INT3F0D"},
 	{"INTC1080"},
 	{"INTC1081"},
+	{"INTC1099"},
 	{""},
 };
 
diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index f81705f8539aa0b12d156a86aae521aa40b4527d..16e6df441bb344c0f91b40bd76b6322ad3016e72 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -1350,6 +1350,17 @@  config INTEL_MID_WATCHDOG
 
 	  To compile this driver as a module, choose M here.
 
+config INTEL_OC_WATCHDOG
+	tristate "Intel OC Watchdog"
+	depends on X86 && ACPI
+	select WATCHDOG_CORE
+	help
+	  Hardware driver for Intel Over-Clocking watchdog present in
+	  Platform Controller Hub (PCH) chipsets.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called intel_oc_wdt.
+
 config ITCO_WDT
 	tristate "Intel TCO Timer/Watchdog"
 	depends on X86 && PCI
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index 8411626fa162268e8ccd06349f7193b15a9d281a..3a13f3e80a0f460b99b4f1592fcf17cc6428876b 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -149,6 +149,7 @@  obj-$(CONFIG_W83977F_WDT) += w83977f_wdt.o
 obj-$(CONFIG_MACHZ_WDT) += machzwd.o
 obj-$(CONFIG_SBC_EPX_C3_WATCHDOG) += sbc_epx_c3.o
 obj-$(CONFIG_INTEL_MID_WATCHDOG) += intel-mid_wdt.o
+obj-$(CONFIG_INTEL_OC_WATCHDOG) += intel_oc_wdt.o
 obj-$(CONFIG_INTEL_MEI_WDT) += mei_wdt.o
 obj-$(CONFIG_NI903X_WDT) += ni903x_wdt.o
 obj-$(CONFIG_NIC7018_WDT) += nic7018_wdt.o
diff --git a/drivers/watchdog/intel_oc_wdt.c b/drivers/watchdog/intel_oc_wdt.c
new file mode 100644
index 0000000000000000000000000000000000000000..0a2df3440024090f7e342fe7da895a7930ac09b2
--- /dev/null
+++ b/drivers/watchdog/intel_oc_wdt.c
@@ -0,0 +1,235 @@ 
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Intel OC Watchdog driver
+ *
+ * Copyright (C) 2025, Siemens SA
+ * Author: Diogo Ivo <diogo.ivo@siemens.com>
+ */
+
+#define DRV_NAME	"intel_oc_wdt"
+
+#include <linux/acpi.h>
+#include <linux/bits.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/platform_device.h>
+#include <linux/watchdog.h>
+
+#define INTEL_OC_WDT_TOV		GENMASK(9, 0)
+#define INTEL_OC_WDT_MIN_TOV		1
+#define INTEL_OC_WDT_MAX_TOV		1024
+
+/*
+ * One-time writable lock bit. If set forbids
+ * modification of itself, _TOV and _EN until
+ * next reboot.
+ */
+#define INTEL_OC_WDT_CTL_LCK		BIT(12)
+
+#define INTEL_OC_WDT_EN			BIT(14)
+#define INTEL_OC_WDT_NO_ICCSURV_STS	BIT(24)
+#define INTEL_OC_WDT_ICCSURV_STS	BIT(25)
+#define INTEL_OC_WDT_RLD		BIT(31)
+
+#define INTEL_OC_WDT_STS_BITS (INTEL_OC_WDT_NO_ICCSURV_STS | \
+			       INTEL_OC_WDT_ICCSURV_STS)
+
+#define INTEL_OC_WDT_CTRL_REG(wdt)	((wdt)->ctrl_res->start)
+
+struct intel_oc_wdt {
+	struct watchdog_device wdd;
+	struct resource *ctrl_res;
+	bool locked;
+};
+
+#define WDT_HEARTBEAT			60
+static int heartbeat = WDT_HEARTBEAT;
+module_param(heartbeat, uint, 0);
+MODULE_PARM_DESC(heartbeat, "Watchdog heartbeats in seconds. (default="
+		 __MODULE_STRING(WDT_HEARTBEAT) ")");
+
+static bool nowayout = WATCHDOG_NOWAYOUT;
+module_param(nowayout, bool, 0);
+MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
+		 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
+
+static int intel_oc_wdt_start(struct watchdog_device *wdd)
+{
+	struct intel_oc_wdt *oc_wdt = watchdog_get_drvdata(wdd);
+
+	if (oc_wdt->locked)
+		return 0;
+
+	outl(inl(INTEL_OC_WDT_CTRL_REG(oc_wdt)) | INTEL_OC_WDT_EN,
+	     INTEL_OC_WDT_CTRL_REG(oc_wdt));
+
+	return 0;
+}
+
+static int intel_oc_wdt_stop(struct watchdog_device *wdd)
+{
+	struct intel_oc_wdt *oc_wdt = watchdog_get_drvdata(wdd);
+
+	outl(inl(INTEL_OC_WDT_CTRL_REG(oc_wdt)) & ~INTEL_OC_WDT_EN,
+	     INTEL_OC_WDT_CTRL_REG(oc_wdt));
+
+	return 0;
+}
+
+static int intel_oc_wdt_ping(struct watchdog_device *wdd)
+{
+	struct intel_oc_wdt *oc_wdt = watchdog_get_drvdata(wdd);
+
+	outl(inl(INTEL_OC_WDT_CTRL_REG(oc_wdt)) | INTEL_OC_WDT_RLD,
+	     INTEL_OC_WDT_CTRL_REG(oc_wdt));
+
+	return 0;
+}
+
+static int intel_oc_wdt_set_timeout(struct watchdog_device *wdd,
+				    unsigned int t)
+{
+	struct intel_oc_wdt *oc_wdt = watchdog_get_drvdata(wdd);
+
+	outl((inl(INTEL_OC_WDT_CTRL_REG(oc_wdt)) & ~INTEL_OC_WDT_TOV) | (t - 1),
+	     INTEL_OC_WDT_CTRL_REG(oc_wdt));
+
+	wdd->timeout = t;
+
+	return 0;
+}
+
+static const struct watchdog_info intel_oc_wdt_info = {
+	.options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,
+	.identity = DRV_NAME,
+};
+
+static const struct watchdog_ops intel_oc_wdt_ops = {
+	.owner = THIS_MODULE,
+	.start = intel_oc_wdt_start,
+	.stop = intel_oc_wdt_stop,
+	.ping = intel_oc_wdt_ping,
+	.set_timeout = intel_oc_wdt_set_timeout,
+};
+
+static int intel_oc_wdt_setup(struct intel_oc_wdt *oc_wdt)
+{
+	struct watchdog_info *info;
+	unsigned long val;
+
+	val = inl(INTEL_OC_WDT_CTRL_REG(oc_wdt));
+
+	if (val & INTEL_OC_WDT_STS_BITS)
+		oc_wdt->wdd.bootstatus |= WDIOF_CARDRESET;
+
+	oc_wdt->locked = !!(val & INTEL_OC_WDT_CTL_LCK);
+
+	if (val & INTEL_OC_WDT_EN) {
+		/*
+		 * No need to issue a ping here to "commit" the new timeout
+		 * value to hardware as the watchdog core schedules one
+		 * immediately when registering the watchdog.
+		 */
+		set_bit(WDOG_HW_RUNNING, &oc_wdt->wdd.status);
+
+		if (oc_wdt->locked) {
+			info = (struct watchdog_info *)&intel_oc_wdt_info;
+			/*
+			 * Set nowayout unconditionally as we cannot stop
+			 * the watchdog and read the current timeout.
+			 */
+			nowayout = true;
+
+			oc_wdt->wdd.timeout = (val & INTEL_OC_WDT_TOV) + 1;
+			info->options &= ~WDIOF_SETTIMEOUT;
+
+			dev_info(oc_wdt->wdd.parent,
+				 "Register access locked, heartbeat fixed at: %u s\n",
+				 oc_wdt->wdd.timeout);
+		}
+	} else if (oc_wdt->locked) {
+		/*
+		 * In case the watchdog is disabled and locked there
+		 * is nothing we can do with it so just fail probing.
+		 */
+		return -EACCES;
+	}
+
+	val &= ~INTEL_OC_WDT_TOV;
+	outl(val | (oc_wdt->wdd.timeout - 1), INTEL_OC_WDT_CTRL_REG(oc_wdt));
+
+	return 0;
+}
+
+static int intel_oc_wdt_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct intel_oc_wdt *oc_wdt;
+	struct watchdog_device *wdd;
+	int ret;
+
+	oc_wdt = devm_kzalloc(&pdev->dev, sizeof(*oc_wdt), GFP_KERNEL);
+	if (!oc_wdt)
+		return -ENOMEM;
+
+	oc_wdt->ctrl_res = platform_get_resource(pdev, IORESOURCE_IO, 0);
+	if (!oc_wdt->ctrl_res) {
+		dev_err(&pdev->dev, "missing I/O resource\n");
+		return -ENODEV;
+	}
+
+	if (!devm_request_region(&pdev->dev, oc_wdt->ctrl_res->start,
+				 resource_size(oc_wdt->ctrl_res), pdev->name)) {
+		dev_err(dev, "I/O address 0x%04llx already in use, device disabled\n",
+		       (u64)(oc_wdt->ctrl_res->start));
+		return -EBUSY;
+	}
+
+	wdd = &oc_wdt->wdd;
+	wdd->min_timeout = INTEL_OC_WDT_MIN_TOV;
+	wdd->max_timeout = INTEL_OC_WDT_MAX_TOV;
+	wdd->info = &intel_oc_wdt_info;
+	wdd->ops = &intel_oc_wdt_ops;
+	wdd->parent = dev;
+
+	ret = watchdog_init_timeout(wdd, heartbeat, dev);
+	if (ret) {
+		dev_info(dev, "invalid heartbeat (%d): %u s, defaulting to %d s\n",
+			 ret, heartbeat, WDT_HEARTBEAT);
+		wdd->timeout = WDT_HEARTBEAT;
+	}
+
+	ret = intel_oc_wdt_setup(oc_wdt);
+	if (ret)
+		return ret;
+
+	watchdog_set_drvdata(wdd, oc_wdt);
+	watchdog_set_nowayout(wdd, nowayout);
+	watchdog_stop_on_reboot(wdd);
+	watchdog_stop_on_unregister(wdd);
+
+	return devm_watchdog_register_device(dev, wdd);
+}
+
+static const struct acpi_device_id intel_oc_wdt_match[] = {
+	{ "INT3F0D" },
+	{ "INTC1099" },
+	{ },
+};
+MODULE_DEVICE_TABLE(acpi, intel_oc_wdt_match);
+
+static struct platform_driver intel_oc_wdt_platform_driver = {
+	.driver = {
+		.name = DRV_NAME,
+		.acpi_match_table = ACPI_PTR(intel_oc_wdt_match),
+	},
+	.probe = intel_oc_wdt_probe,
+};
+
+module_platform_driver(intel_oc_wdt_platform_driver);
+
+MODULE_AUTHOR("Diogo Ivo <diogo.ivo@siemens.com>");
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Intel OC Watchdog driver");
+MODULE_ALIAS("platform:" DRV_NAME);