[PATCH v6] platform/chrome: cros_ec: Query EC protocol version if EC transitions between RO/RW

[PATCH v6] platform/chrome: cros_ec: Query EC protocol version if EC transitions between RO/RW

[Yicheng Li]

RO and RW of EC may have different EC protocol version. If EC transitions
between RO and RW, but AP does not reboot (this is true for fingerprint
microcontroller / cros_fp, but not true for main ec / cros_ec), the AP
still uses the protocol version queried before transition, which can
cause problems. In the case of fingerprint microcontroller, this causes
AP to send the wrong version of EC_CMD_GET_NEXT_EVENT to RO in the
interrupt handler, which in turn prevents RO to clear the interrupt
line to AP, in an infinite loop.

Once an EC_HOST_EVENT_INTERFACE_READY is received, we know that there
might have been a transition between RO and RW, so re-query the protocol.

Signed-off-by: Yicheng Li <yichengli@chromium.org>
---
Hi Enric and Marek,

> This patch landed recently in linux-next as commit
> 241a69ae8ea8e2defec751fe55dac1287aa044b8. Sadly, it causes following
> kernel oops on any key press on Samsung Exynos-based Chromebooks (Snow,
> Peach-Pit and Peach-Pi):


> Many thanks for report the issue, we will take a look ASAP and revert
> this commit meanwhile.


> Simply removing the BUG_ON() from cros_ec_get_host_event() function
> fixes the issue, but I don't know the protocol details to judge if this
> is the correct way of fixing it.

The issue was those Samsung Chromebooks (Snow, Peach-Pit and Peach-Pi)
do not support mkbp events, yet we applied the same thing to them, which
we shouldn't. This v6 should fix it: I Just added a check

	if (ec_dev->mkbp_event_supported)

in cros_ec_register().



drivers/platform/chrome/cros_ec.c           | 29 +++++++++++++++++++++
 include/linux/platform_data/cros_ec_proto.h |  3 +++
 2 files changed, 32 insertions(+)

diff --git a/drivers/platform/chrome/cros_ec.c b/drivers/platform/chrome/cros_ec.c
index 9b2d07422e17..f16804db805b 100644
--- a/drivers/platform/chrome/cros_ec.c
+++ b/drivers/platform/chrome/cros_ec.c
@@ -104,6 +104,23 @@ static int cros_ec_sleep_event(struct cros_ec_device *ec_dev, u8 sleep_event)
 	return ret;
 }
 
+static int cros_ec_ready_event(struct notifier_block *nb,
+	unsigned long queued_during_suspend, void *_notify)
+{
+	struct cros_ec_device *ec_dev = container_of(nb, struct cros_ec_device,
+						     notifier_ready);
+	u32 host_event = cros_ec_get_host_event(ec_dev);
+
+	if (host_event & EC_HOST_EVENT_MASK(EC_HOST_EVENT_INTERFACE_READY)) {
+		mutex_lock(&ec_dev->lock);
+		cros_ec_query_all(ec_dev);
+		mutex_unlock(&ec_dev->lock);
+		return NOTIFY_OK;
+	}
+
+	return NOTIFY_DONE;
+}
+
 /**
  * cros_ec_register() - Register a new ChromeOS EC, using the provided info.
  * @ec_dev: Device to register.
@@ -201,6 +218,18 @@ int cros_ec_register(struct cros_ec_device *ec_dev)
 		dev_dbg(ec_dev->dev, "Error %d clearing sleep event to ec",
 			err);
 
+	if (ec_dev->mkbp_event_supported) {
+		/*
+		 * Register the notifier for EC_HOST_EVENT_INTERFACE_READY
+		 * event.
+		 */
+		ec_dev->notifier_ready.notifier_call = cros_ec_ready_event;
+		err = blocking_notifier_chain_register(
+			&ec_dev->event_notifier, &ec_dev->notifier_ready);
+		if (err)
+			return err;
+	}
+
 	dev_info(dev, "Chrome EC device registered\n");
 
 	return 0;
diff --git a/include/linux/platform_data/cros_ec_proto.h b/include/linux/platform_data/cros_ec_proto.h
index 0d4e4aaed37a..a1c545c464e7 100644
--- a/include/linux/platform_data/cros_ec_proto.h
+++ b/include/linux/platform_data/cros_ec_proto.h
@@ -121,6 +121,8 @@ struct cros_ec_command {
  * @event_data: Raw payload transferred with the MKBP event.
  * @event_size: Size in bytes of the event data.
  * @host_event_wake_mask: Mask of host events that cause wake from suspend.
+ * @notifier_ready: The notifier_block to let the kernel re-query EC
+ *      communication protocol when the EC sends EC_HOST_EVENT_INTERFACE_READY.
  * @ec: The platform_device used by the mfd driver to interface with the
  *      main EC.
  * @pd: The platform_device used by the mfd driver to interface with the
@@ -161,6 +163,7 @@ struct cros_ec_device {
 	int event_size;
 	u32 host_event_wake_mask;
 	u32 last_resume_result;
+	struct notifier_block notifier_ready;
 
 	/* The platform devices used by the mfd driver */
 	struct platform_device *ec;
-- 
2.24.1

Re: [PATCH v6] platform/chrome: cros_ec: Query EC protocol version if EC transitions between RO/RW

[Marek Szyprowski]

Hi

On 03.02.2020 23:53, Yicheng Li wrote:
> RO and RW of EC may have different EC protocol version. If EC transitions
> between RO and RW, but AP does not reboot (this is true for fingerprint
> microcontroller / cros_fp, but not true for main ec / cros_ec), the AP
> still uses the protocol version queried before transition, which can
> cause problems. In the case of fingerprint microcontroller, this causes
> AP to send the wrong version of EC_CMD_GET_NEXT_EVENT to RO in the
> interrupt handler, which in turn prevents RO to clear the interrupt
> line to AP, in an infinite loop.
>
> Once an EC_HOST_EVENT_INTERFACE_READY is received, we know that there
> might have been a transition between RO and RW, so re-query the protocol.
>
> Signed-off-by: Yicheng Li <yichengli@chromium.org>

Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>

Works fine on Samsung Exynos-based Chromebooks: Snow, Peach-Pit and 
Peach-Pi.

> ---
> Hi Enric and Marek,
>
>> This patch landed recently in linux-next as commit
>> 241a69ae8ea8e2defec751fe55dac1287aa044b8. Sadly, it causes following
>> kernel oops on any key press on Samsung Exynos-based Chromebooks (Snow,
>> Peach-Pit and Peach-Pi):
>
>> Many thanks for report the issue, we will take a look ASAP and revert
>> this commit meanwhile.
>
>> Simply removing the BUG_ON() from cros_ec_get_host_event() function
>> fixes the issue, but I don't know the protocol details to judge if this
>> is the correct way of fixing it.
> The issue was those Samsung Chromebooks (Snow, Peach-Pit and Peach-Pi)
> do not support mkbp events, yet we applied the same thing to them, which
> we shouldn't. This v6 should fix it: I Just added a check
>
> 	if (ec_dev->mkbp_event_supported)
>
> in cros_ec_register().
>
>
>
> drivers/platform/chrome/cros_ec.c           | 29 +++++++++++++++++++++
>   include/linux/platform_data/cros_ec_proto.h |  3 +++
>   2 files changed, 32 insertions(+)
>
> diff --git a/drivers/platform/chrome/cros_ec.c b/drivers/platform/chrome/cros_ec.c
> index 9b2d07422e17..f16804db805b 100644
> --- a/drivers/platform/chrome/cros_ec.c
> +++ b/drivers/platform/chrome/cros_ec.c
> @@ -104,6 +104,23 @@ static int cros_ec_sleep_event(struct cros_ec_device *ec_dev, u8 sleep_event)
>   	return ret;
>   }
>   
> +static int cros_ec_ready_event(struct notifier_block *nb,
> +	unsigned long queued_during_suspend, void *_notify)
> +{
> +	struct cros_ec_device *ec_dev = container_of(nb, struct cros_ec_device,
> +						     notifier_ready);
> +	u32 host_event = cros_ec_get_host_event(ec_dev);
> +
> +	if (host_event & EC_HOST_EVENT_MASK(EC_HOST_EVENT_INTERFACE_READY)) {
> +		mutex_lock(&ec_dev->lock);
> +		cros_ec_query_all(ec_dev);
> +		mutex_unlock(&ec_dev->lock);
> +		return NOTIFY_OK;
> +	}
> +
> +	return NOTIFY_DONE;
> +}
> +
>   /**
>    * cros_ec_register() - Register a new ChromeOS EC, using the provided info.
>    * @ec_dev: Device to register.
> @@ -201,6 +218,18 @@ int cros_ec_register(struct cros_ec_device *ec_dev)
>   		dev_dbg(ec_dev->dev, "Error %d clearing sleep event to ec",
>   			err);
>   
> +	if (ec_dev->mkbp_event_supported) {
> +		/*
> +		 * Register the notifier for EC_HOST_EVENT_INTERFACE_READY
> +		 * event.
> +		 */
> +		ec_dev->notifier_ready.notifier_call = cros_ec_ready_event;
> +		err = blocking_notifier_chain_register(
> +			&ec_dev->event_notifier, &ec_dev->notifier_ready);
> +		if (err)
> +			return err;
> +	}
> +
>   	dev_info(dev, "Chrome EC device registered\n");
>   
>   	return 0;
> diff --git a/include/linux/platform_data/cros_ec_proto.h b/include/linux/platform_data/cros_ec_proto.h
> index 0d4e4aaed37a..a1c545c464e7 100644
> --- a/include/linux/platform_data/cros_ec_proto.h
> +++ b/include/linux/platform_data/cros_ec_proto.h
> @@ -121,6 +121,8 @@ struct cros_ec_command {
>    * @event_data: Raw payload transferred with the MKBP event.
>    * @event_size: Size in bytes of the event data.
>    * @host_event_wake_mask: Mask of host events that cause wake from suspend.
> + * @notifier_ready: The notifier_block to let the kernel re-query EC
> + *      communication protocol when the EC sends EC_HOST_EVENT_INTERFACE_READY.
>    * @ec: The platform_device used by the mfd driver to interface with the
>    *      main EC.
>    * @pd: The platform_device used by the mfd driver to interface with the
> @@ -161,6 +163,7 @@ struct cros_ec_device {
>   	int event_size;
>   	u32 host_event_wake_mask;
>   	u32 last_resume_result;
> +	struct notifier_block notifier_ready;
>   
>   	/* The platform devices used by the mfd driver */
>   	struct platform_device *ec;

Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland

Re: [PATCH v6] platform/chrome: cros_ec: Query EC protocol version if EC transitions between RO/RW

[Gwendal Grignou]

Reviewed-by: Gwendal Grignou <gwendal@chromium.org>

On Mon, Feb 3, 2020 at 11:30 PM Marek Szyprowski
<m.szyprowski@samsung.com> wrote:
>
> Hi
>
> On 03.02.2020 23:53, Yicheng Li wrote:
> > RO and RW of EC may have different EC protocol version. If EC transitions
> > between RO and RW, but AP does not reboot (this is true for fingerprint
> > microcontroller / cros_fp, but not true for main ec / cros_ec), the AP
> > still uses the protocol version queried before transition, which can
> > cause problems. In the case of fingerprint microcontroller, this causes
> > AP to send the wrong version of EC_CMD_GET_NEXT_EVENT to RO in the
> > interrupt handler, which in turn prevents RO to clear the interrupt
> > line to AP, in an infinite loop.
> >
> > Once an EC_HOST_EVENT_INTERFACE_READY is received, we know that there
> > might have been a transition between RO and RW, so re-query the protocol.
> >
> > Signed-off-by: Yicheng Li <yichengli@chromium.org>
>
> Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
>
> Works fine on Samsung Exynos-based Chromebooks: Snow, Peach-Pit and
> Peach-Pi.
>
> > ---
> > Hi Enric and Marek,
> >
> >> This patch landed recently in linux-next as commit
> >> 241a69ae8ea8e2defec751fe55dac1287aa044b8. Sadly, it causes following
> >> kernel oops on any key press on Samsung Exynos-based Chromebooks (Snow,
> >> Peach-Pit and Peach-Pi):
> >
> >> Many thanks for report the issue, we will take a look ASAP and revert
> >> this commit meanwhile.
> >
> >> Simply removing the BUG_ON() from cros_ec_get_host_event() function
> >> fixes the issue, but I don't know the protocol details to judge if this
> >> is the correct way of fixing it.
> > The issue was those Samsung Chromebooks (Snow, Peach-Pit and Peach-Pi)
> > do not support mkbp events, yet we applied the same thing to them, which
> > we shouldn't. This v6 should fix it: I Just added a check
> >
> >       if (ec_dev->mkbp_event_supported)
> >
> > in cros_ec_register().
> >
> >
> >
> > drivers/platform/chrome/cros_ec.c           | 29 +++++++++++++++++++++
> >   include/linux/platform_data/cros_ec_proto.h |  3 +++
> >   2 files changed, 32 insertions(+)
> >
> > diff --git a/drivers/platform/chrome/cros_ec.c b/drivers/platform/chrome/cros_ec.c
> > index 9b2d07422e17..f16804db805b 100644
> > --- a/drivers/platform/chrome/cros_ec.c
> > +++ b/drivers/platform/chrome/cros_ec.c
> > @@ -104,6 +104,23 @@ static int cros_ec_sleep_event(struct cros_ec_device *ec_dev, u8 sleep_event)
> >       return ret;
> >   }
> >
> > +static int cros_ec_ready_event(struct notifier_block *nb,
> > +     unsigned long queued_during_suspend, void *_notify)
> > +{
> > +     struct cros_ec_device *ec_dev = container_of(nb, struct cros_ec_device,
> > +                                                  notifier_ready);
> > +     u32 host_event = cros_ec_get_host_event(ec_dev);
> > +
> > +     if (host_event & EC_HOST_EVENT_MASK(EC_HOST_EVENT_INTERFACE_READY)) {
> > +             mutex_lock(&ec_dev->lock);
> > +             cros_ec_query_all(ec_dev);
> > +             mutex_unlock(&ec_dev->lock);
> > +             return NOTIFY_OK;
> > +     }
> > +
> > +     return NOTIFY_DONE;
> > +}
> > +
> >   /**
> >    * cros_ec_register() - Register a new ChromeOS EC, using the provided info.
> >    * @ec_dev: Device to register.
> > @@ -201,6 +218,18 @@ int cros_ec_register(struct cros_ec_device *ec_dev)
> >               dev_dbg(ec_dev->dev, "Error %d clearing sleep event to ec",
> >                       err);
> >
> > +     if (ec_dev->mkbp_event_supported) {
> > +             /*
> > +              * Register the notifier for EC_HOST_EVENT_INTERFACE_READY
> > +              * event.
> > +              */
> > +             ec_dev->notifier_ready.notifier_call = cros_ec_ready_event;
> > +             err = blocking_notifier_chain_register(
> > +                     &ec_dev->event_notifier, &ec_dev->notifier_ready);
> > +             if (err)
> > +                     return err;
> > +     }
> > +
> >       dev_info(dev, "Chrome EC device registered\n");
> >
> >       return 0;
> > diff --git a/include/linux/platform_data/cros_ec_proto.h b/include/linux/platform_data/cros_ec_proto.h
> > index 0d4e4aaed37a..a1c545c464e7 100644
> > --- a/include/linux/platform_data/cros_ec_proto.h
> > +++ b/include/linux/platform_data/cros_ec_proto.h
> > @@ -121,6 +121,8 @@ struct cros_ec_command {
> >    * @event_data: Raw payload transferred with the MKBP event.
> >    * @event_size: Size in bytes of the event data.
> >    * @host_event_wake_mask: Mask of host events that cause wake from suspend.
> > + * @notifier_ready: The notifier_block to let the kernel re-query EC
> > + *      communication protocol when the EC sends EC_HOST_EVENT_INTERFACE_READY.
> >    * @ec: The platform_device used by the mfd driver to interface with the
> >    *      main EC.
> >    * @pd: The platform_device used by the mfd driver to interface with the
> > @@ -161,6 +163,7 @@ struct cros_ec_device {
> >       int event_size;
> >       u32 host_event_wake_mask;
> >       u32 last_resume_result;
> > +     struct notifier_block notifier_ready;
> >
> >       /* The platform devices used by the mfd driver */
> >       struct platform_device *ec;
>
> Best regards
> --
> Marek Szyprowski, PhD
> Samsung R&D Institute Poland
>

Re: [PATCH v6] platform/chrome: cros_ec: Query EC protocol version if EC transitions between RO/RW

[Enric Balletbo i Serra]

Hi,

On 4/2/20 21:40, Gwendal Grignou wrote:
> Reviewed-by: Gwendal Grignou <gwendal@chromium.org>
> 
> On Mon, Feb 3, 2020 at 11:30 PM Marek Szyprowski
> <m.szyprowski@samsung.com> wrote:
>>
>> Hi
>>
>> On 03.02.2020 23:53, Yicheng Li wrote:
>>> RO and RW of EC may have different EC protocol version. If EC transitions
>>> between RO and RW, but AP does not reboot (this is true for fingerprint
>>> microcontroller / cros_fp, but not true for main ec / cros_ec), the AP
>>> still uses the protocol version queried before transition, which can
>>> cause problems. In the case of fingerprint microcontroller, this causes
>>> AP to send the wrong version of EC_CMD_GET_NEXT_EVENT to RO in the
>>> interrupt handler, which in turn prevents RO to clear the interrupt
>>> line to AP, in an infinite loop.
>>>
>>> Once an EC_HOST_EVENT_INTERFACE_READY is received, we know that there
>>> might have been a transition between RO and RW, so re-query the protocol.
>>>
>>> Signed-off-by: Yicheng Li <yichengli@chromium.org>
>>
>> Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
>>
>> Works fine on Samsung Exynos-based Chromebooks: Snow, Peach-Pit and
>> Peach-Pi.
>>

Thanks, we will pick this patch once 5.6-rc1 is out. For my own reference:

Acked-for-chrome-platform: Enric Balletbo i Serra <enric.balletbo@collabora.com>


>>> ---
>>> Hi Enric and Marek,
>>>
>>>> This patch landed recently in linux-next as commit
>>>> 241a69ae8ea8e2defec751fe55dac1287aa044b8. Sadly, it causes following
>>>> kernel oops on any key press on Samsung Exynos-based Chromebooks (Snow,
>>>> Peach-Pit and Peach-Pi):
>>>
>>>> Many thanks for report the issue, we will take a look ASAP and revert
>>>> this commit meanwhile.
>>>
>>>> Simply removing the BUG_ON() from cros_ec_get_host_event() function
>>>> fixes the issue, but I don't know the protocol details to judge if this
>>>> is the correct way of fixing it.
>>> The issue was those Samsung Chromebooks (Snow, Peach-Pit and Peach-Pi)
>>> do not support mkbp events, yet we applied the same thing to them, which
>>> we shouldn't. This v6 should fix it: I Just added a check
>>>
>>>       if (ec_dev->mkbp_event_supported)
>>>
>>> in cros_ec_register().
>>>
>>>
>>>
>>> drivers/platform/chrome/cros_ec.c           | 29 +++++++++++++++++++++
>>>   include/linux/platform_data/cros_ec_proto.h |  3 +++
>>>   2 files changed, 32 insertions(+)
>>>
>>> diff --git a/drivers/platform/chrome/cros_ec.c b/drivers/platform/chrome/cros_ec.c
>>> index 9b2d07422e17..f16804db805b 100644
>>> --- a/drivers/platform/chrome/cros_ec.c
>>> +++ b/drivers/platform/chrome/cros_ec.c
>>> @@ -104,6 +104,23 @@ static int cros_ec_sleep_event(struct cros_ec_device *ec_dev, u8 sleep_event)
>>>       return ret;
>>>   }
>>>
>>> +static int cros_ec_ready_event(struct notifier_block *nb,
>>> +     unsigned long queued_during_suspend, void *_notify)
>>> +{
>>> +     struct cros_ec_device *ec_dev = container_of(nb, struct cros_ec_device,
>>> +                                                  notifier_ready);
>>> +     u32 host_event = cros_ec_get_host_event(ec_dev);
>>> +
>>> +     if (host_event & EC_HOST_EVENT_MASK(EC_HOST_EVENT_INTERFACE_READY)) {
>>> +             mutex_lock(&ec_dev->lock);
>>> +             cros_ec_query_all(ec_dev);
>>> +             mutex_unlock(&ec_dev->lock);
>>> +             return NOTIFY_OK;
>>> +     }
>>> +
>>> +     return NOTIFY_DONE;
>>> +}
>>> +
>>>   /**
>>>    * cros_ec_register() - Register a new ChromeOS EC, using the provided info.
>>>    * @ec_dev: Device to register.
>>> @@ -201,6 +218,18 @@ int cros_ec_register(struct cros_ec_device *ec_dev)
>>>               dev_dbg(ec_dev->dev, "Error %d clearing sleep event to ec",
>>>                       err);
>>>
>>> +     if (ec_dev->mkbp_event_supported) {
>>> +             /*
>>> +              * Register the notifier for EC_HOST_EVENT_INTERFACE_READY
>>> +              * event.
>>> +              */
>>> +             ec_dev->notifier_ready.notifier_call = cros_ec_ready_event;
>>> +             err = blocking_notifier_chain_register(
>>> +                     &ec_dev->event_notifier, &ec_dev->notifier_ready);
>>> +             if (err)
>>> +                     return err;
>>> +     }
>>> +
>>>       dev_info(dev, "Chrome EC device registered\n");
>>>
>>>       return 0;
>>> diff --git a/include/linux/platform_data/cros_ec_proto.h b/include/linux/platform_data/cros_ec_proto.h
>>> index 0d4e4aaed37a..a1c545c464e7 100644
>>> --- a/include/linux/platform_data/cros_ec_proto.h
>>> +++ b/include/linux/platform_data/cros_ec_proto.h
>>> @@ -121,6 +121,8 @@ struct cros_ec_command {
>>>    * @event_data: Raw payload transferred with the MKBP event.
>>>    * @event_size: Size in bytes of the event data.
>>>    * @host_event_wake_mask: Mask of host events that cause wake from suspend.
>>> + * @notifier_ready: The notifier_block to let the kernel re-query EC
>>> + *      communication protocol when the EC sends EC_HOST_EVENT_INTERFACE_READY.
>>>    * @ec: The platform_device used by the mfd driver to interface with the
>>>    *      main EC.
>>>    * @pd: The platform_device used by the mfd driver to interface with the
>>> @@ -161,6 +163,7 @@ struct cros_ec_device {
>>>       int event_size;
>>>       u32 host_event_wake_mask;
>>>       u32 last_resume_result;
>>> +     struct notifier_block notifier_ready;
>>>
>>>       /* The platform devices used by the mfd driver */
>>>       struct platform_device *ec;
>>
>> Best regards
>> --
>> Marek Szyprowski, PhD
>> Samsung R&D Institute Poland
>>

Re: [PATCH v6] platform/chrome: cros_ec: Query EC protocol version if EC transitions between RO/RW

[Enric Balletbo i Serra]

On 3/2/20 23:53, Yicheng Li wrote:
> RO and RW of EC may have different EC protocol version. If EC transitions
> between RO and RW, but AP does not reboot (this is true for fingerprint
> microcontroller / cros_fp, but not true for main ec / cros_ec), the AP
> still uses the protocol version queried before transition, which can
> cause problems. In the case of fingerprint microcontroller, this causes
> AP to send the wrong version of EC_CMD_GET_NEXT_EVENT to RO in the
> interrupt handler, which in turn prevents RO to clear the interrupt
> line to AP, in an infinite loop.
> 
> Once an EC_HOST_EVENT_INTERFACE_READY is received, we know that there
> might have been a transition between RO and RW, so re-query the protocol.
> 
> Signed-off-by: Yicheng Li <yichengli@chromium.org>
> ---

Queued for 5.7 with all the collected tags, thanks.