diff mbox series

[v4,1/3] bus: mhi: host: add mhi_power_down_keep_dev()

Message ID 20240228022243.17762-2-quic_bqiang@quicinc.com
State Superseded
Headers show
Series wifi: ath11k: hibernation support | expand

Commit Message

Baochen Qiang Feb. 28, 2024, 2:22 a.m. UTC
ath11k fails to resume:

ath11k_pci 0000:06:00.0: timeout while waiting for restart complete

This happens because when calling mhi_sync_power_up() the MHI subsystem
eventually calls device_add() from mhi_create_devices() but the device
creation is deferred:

mhi mhi0_IPCR: Driver qcom_mhi_qrtr force probe deferral

The reason for deferring device creation is explained in dpm_prepare():

        /*
         * It is unsafe if probing of devices will happen during suspend or
         * hibernation and system behavior will be unpredictable in this case.
         * So, let's prohibit device's probing here and defer their probes
         * instead. The normal behavior will be restored in dpm_complete().
         */

Because the device probe is deferred, the qcom_mhi_qrtr_probe() is not
called and thus MHI channels are not prepared:

So what this means that QRTR is not delivering messages and the QMI connection
is not working between ath11k and the firmware, resulting a failure in firmware
initialization.

To fix this add new function mhi_power_down_keep_dev() which doesn't destroy
the devices for channels during power down. This way we avoid probe defer issue
and finally can get ath11k hibernation working with the following patches.

Tested-on: WCN6855 hw2.0 PCI WLAN.HSP.1.1-03125-QCAHSPSWPL_V1_V2_SILICONZ_LITE-3.6510.30

Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>
Signed-off-by: Baochen Qiang <quic_bqiang@quicinc.com>
---
 drivers/bus/mhi/host/internal.h |  4 +++-
 drivers/bus/mhi/host/pm.c       | 42 ++++++++++++++++++++++++++++-----
 include/linux/mhi.h             | 18 +++++++++++++-
 3 files changed, 56 insertions(+), 8 deletions(-)

Comments

Jeff Johnson Feb. 28, 2024, 3:09 p.m. UTC | #1
On 2/27/2024 6:22 PM, Baochen Qiang wrote:
> ath11k fails to resume:
> 
> ath11k_pci 0000:06:00.0: timeout while waiting for restart complete
> 
> This happens because when calling mhi_sync_power_up() the MHI subsystem
> eventually calls device_add() from mhi_create_devices() but the device
> creation is deferred:
> 
> mhi mhi0_IPCR: Driver qcom_mhi_qrtr force probe deferral
> 
> The reason for deferring device creation is explained in dpm_prepare():
> 
>         /*
>          * It is unsafe if probing of devices will happen during suspend or
>          * hibernation and system behavior will be unpredictable in this case.
>          * So, let's prohibit device's probing here and defer their probes
>          * instead. The normal behavior will be restored in dpm_complete().
>          */
> 
> Because the device probe is deferred, the qcom_mhi_qrtr_probe() is not
> called and thus MHI channels are not prepared:
> 
> So what this means that QRTR is not delivering messages and the QMI connection
> is not working between ath11k and the firmware, resulting a failure in firmware
> initialization.
> 
> To fix this add new function mhi_power_down_keep_dev() which doesn't destroy
> the devices for channels during power down. This way we avoid probe defer issue
> and finally can get ath11k hibernation working with the following patches.
> 
> Tested-on: WCN6855 hw2.0 PCI WLAN.HSP.1.1-03125-QCAHSPSWPL_V1_V2_SILICONZ_LITE-3.6510.30
> 
> Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>
> Signed-off-by: Baochen Qiang <quic_bqiang@quicinc.com>
Reviewed-by: Jeff Johnson <quic_jjohnson@quicinc.com>
Manivannan Sadhasivam Feb. 29, 2024, 10:12 a.m. UTC | #2
On Wed, Feb 28, 2024 at 10:22:41AM +0800, Baochen Qiang wrote:
> ath11k fails to resume:
> 
> ath11k_pci 0000:06:00.0: timeout while waiting for restart complete
> 
> This happens because when calling mhi_sync_power_up() the MHI subsystem
> eventually calls device_add() from mhi_create_devices() but the device
> creation is deferred:
> 
> mhi mhi0_IPCR: Driver qcom_mhi_qrtr force probe deferral
> 
> The reason for deferring device creation is explained in dpm_prepare():
> 
>         /*
>          * It is unsafe if probing of devices will happen during suspend or
>          * hibernation and system behavior will be unpredictable in this case.
>          * So, let's prohibit device's probing here and defer their probes
>          * instead. The normal behavior will be restored in dpm_complete().
>          */
> 
> Because the device probe is deferred, the qcom_mhi_qrtr_probe() is not
> called and thus MHI channels are not prepared:
> 
> So what this means that QRTR is not delivering messages and the QMI connection
> is not working between ath11k and the firmware, resulting a failure in firmware
> initialization.
> 
> To fix this add new function mhi_power_down_keep_dev() which doesn't destroy
> the devices for channels during power down. This way we avoid probe defer issue
> and finally can get ath11k hibernation working with the following patches.
> 
> Tested-on: WCN6855 hw2.0 PCI WLAN.HSP.1.1-03125-QCAHSPSWPL_V1_V2_SILICONZ_LITE-3.6510.30
> 
> Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>

Did Kalle co-author this patch? If so, his Co-developed-by tag should be
added.

> Signed-off-by: Baochen Qiang <quic_bqiang@quicinc.com>

Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

- Mani

> ---
>  drivers/bus/mhi/host/internal.h |  4 +++-
>  drivers/bus/mhi/host/pm.c       | 42 ++++++++++++++++++++++++++++-----
>  include/linux/mhi.h             | 18 +++++++++++++-
>  3 files changed, 56 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/bus/mhi/host/internal.h b/drivers/bus/mhi/host/internal.h
> index 5fe49311b8eb..aaad40a07f69 100644
> --- a/drivers/bus/mhi/host/internal.h
> +++ b/drivers/bus/mhi/host/internal.h
> @@ -80,6 +80,7 @@ enum dev_st_transition {
>  	DEV_ST_TRANSITION_FP,
>  	DEV_ST_TRANSITION_SYS_ERR,
>  	DEV_ST_TRANSITION_DISABLE,
> +	DEV_ST_TRANSITION_DISABLE_DESTROY_DEVICE,
>  	DEV_ST_TRANSITION_MAX,
>  };
>  
> @@ -90,7 +91,8 @@ enum dev_st_transition {
>  	dev_st_trans(MISSION_MODE,	"MISSION MODE")		\
>  	dev_st_trans(FP,		"FLASH PROGRAMMER")	\
>  	dev_st_trans(SYS_ERR,		"SYS ERROR")		\
> -	dev_st_trans_end(DISABLE,	"DISABLE")
> +	dev_st_trans(DISABLE,		"DISABLE")		\
> +	dev_st_trans_end(DISABLE_DESTROY_DEVICE, "DISABLE (DESTROY DEVICE)")
>  
>  extern const char * const dev_state_tran_str[DEV_ST_TRANSITION_MAX];
>  #define TO_DEV_STATE_TRANS_STR(state) (((state) >= DEV_ST_TRANSITION_MAX) ? \
> diff --git a/drivers/bus/mhi/host/pm.c b/drivers/bus/mhi/host/pm.c
> index 8b40d3f01acc..11c0e751f223 100644
> --- a/drivers/bus/mhi/host/pm.c
> +++ b/drivers/bus/mhi/host/pm.c
> @@ -468,7 +468,8 @@ static int mhi_pm_mission_mode_transition(struct mhi_controller *mhi_cntrl)
>  }
>  
>  /* Handle shutdown transitions */
> -static void mhi_pm_disable_transition(struct mhi_controller *mhi_cntrl)
> +static void mhi_pm_disable_transition(struct mhi_controller *mhi_cntrl,
> +				      bool destroy_device)
>  {
>  	enum mhi_pm_state cur_state;
>  	struct mhi_event *mhi_event;
> @@ -530,8 +531,16 @@ static void mhi_pm_disable_transition(struct mhi_controller *mhi_cntrl)
>  	dev_dbg(dev, "Waiting for all pending threads to complete\n");
>  	wake_up_all(&mhi_cntrl->state_event);
>  
> -	dev_dbg(dev, "Reset all active channels and remove MHI devices\n");
> -	device_for_each_child(&mhi_cntrl->mhi_dev->dev, NULL, mhi_destroy_device);
> +	/*
> +	 * Only destroy the 'struct device' for channels if indicated by the
> +	 * 'destroy_device' flag. Because, during system suspend or hibernation
> +	 * state, there is no need to destroy the 'struct device' as the endpoint
> +	 * device would still be physically attached to the machine.
> +	 */
> +	if (destroy_device) {
> +		dev_dbg(dev, "Reset all active channels and remove MHI devices\n");
> +		device_for_each_child(&mhi_cntrl->mhi_dev->dev, NULL, mhi_destroy_device);
> +	}
>  
>  	mutex_lock(&mhi_cntrl->pm_mutex);
>  
> @@ -821,7 +830,10 @@ void mhi_pm_st_worker(struct work_struct *work)
>  			mhi_pm_sys_error_transition(mhi_cntrl);
>  			break;
>  		case DEV_ST_TRANSITION_DISABLE:
> -			mhi_pm_disable_transition(mhi_cntrl);
> +			mhi_pm_disable_transition(mhi_cntrl, false);
> +			break;
> +		case DEV_ST_TRANSITION_DISABLE_DESTROY_DEVICE:
> +			mhi_pm_disable_transition(mhi_cntrl, true);
>  			break;
>  		default:
>  			break;
> @@ -1175,7 +1187,8 @@ int mhi_async_power_up(struct mhi_controller *mhi_cntrl)
>  }
>  EXPORT_SYMBOL_GPL(mhi_async_power_up);
>  
> -void mhi_power_down(struct mhi_controller *mhi_cntrl, bool graceful)
> +static void __mhi_power_down(struct mhi_controller *mhi_cntrl, bool graceful,
> +			     bool destroy_device)
>  {
>  	enum mhi_pm_state cur_state, transition_state;
>  	struct device *dev = &mhi_cntrl->mhi_dev->dev;
> @@ -1211,15 +1224,32 @@ void mhi_power_down(struct mhi_controller *mhi_cntrl, bool graceful)
>  	write_unlock_irq(&mhi_cntrl->pm_lock);
>  	mutex_unlock(&mhi_cntrl->pm_mutex);
>  
> -	mhi_queue_state_transition(mhi_cntrl, DEV_ST_TRANSITION_DISABLE);
> +	if (destroy_device)
> +		mhi_queue_state_transition(mhi_cntrl,
> +					   DEV_ST_TRANSITION_DISABLE_DESTROY_DEVICE);
> +	else
> +		mhi_queue_state_transition(mhi_cntrl,
> +					   DEV_ST_TRANSITION_DISABLE);
>  
>  	/* Wait for shutdown to complete */
>  	flush_work(&mhi_cntrl->st_worker);
>  
>  	disable_irq(mhi_cntrl->irq[0]);
>  }
> +
> +void mhi_power_down(struct mhi_controller *mhi_cntrl, bool graceful)
> +{
> +	__mhi_power_down(mhi_cntrl, graceful, true);
> +}
>  EXPORT_SYMBOL_GPL(mhi_power_down);
>  
> +void mhi_power_down_keep_dev(struct mhi_controller *mhi_cntrl,
> +			       bool graceful)
> +{
> +	__mhi_power_down(mhi_cntrl, graceful, false);
> +}
> +EXPORT_SYMBOL_GPL(mhi_power_down_keep_dev);
> +
>  int mhi_sync_power_up(struct mhi_controller *mhi_cntrl)
>  {
>  	int ret = mhi_async_power_up(mhi_cntrl);
> diff --git a/include/linux/mhi.h b/include/linux/mhi.h
> index 77b8c0a26674..cde01e133a1b 100644
> --- a/include/linux/mhi.h
> +++ b/include/linux/mhi.h
> @@ -630,12 +630,28 @@ int mhi_async_power_up(struct mhi_controller *mhi_cntrl);
>  int mhi_sync_power_up(struct mhi_controller *mhi_cntrl);
>  
>  /**
> - * mhi_power_down - Start MHI power down sequence
> + * mhi_power_down - Power down the MHI device and also destroy the
> + *                  'struct device' for the channels associated with it.
> + *                  See also mhi_power_down_keep_dev() which is a variant
> + *                  of this API that keeps the 'struct device' for channels
> + *                  (useful during suspend/hibernation).
>   * @mhi_cntrl: MHI controller
>   * @graceful: Link is still accessible, so do a graceful shutdown process
>   */
>  void mhi_power_down(struct mhi_controller *mhi_cntrl, bool graceful);
>  
> +/**
> + * mhi_power_down_keep_dev - Power down the MHI device but keep the 'struct
> + *                           device' for the channels associated with it.
> + *                           This is a variant of 'mhi_power_down()' and
> + *                           useful in scenarios such as suspend/hibernation
> + *                           where destroying of the 'struct device' is not
> + *                           needed.
> + * @mhi_cntrl: MHI controller
> + * @graceful: Link is still accessible, so do a graceful shutdown process
> + */
> +void mhi_power_down_keep_dev(struct mhi_controller *mhi_cntrl, bool graceful);
> +
>  /**
>   * mhi_unprepare_after_power_down - Free any allocated memory after power down
>   * @mhi_cntrl: MHI controller
> -- 
> 2.25.1
>
Baochen Qiang Feb. 29, 2024, 10:33 a.m. UTC | #3
On 2/29/2024 6:12 PM, Manivannan Sadhasivam wrote:
> On Wed, Feb 28, 2024 at 10:22:41AM +0800, Baochen Qiang wrote:
>> ath11k fails to resume:
>>
>> ath11k_pci 0000:06:00.0: timeout while waiting for restart complete
>>
>> This happens because when calling mhi_sync_power_up() the MHI subsystem
>> eventually calls device_add() from mhi_create_devices() but the device
>> creation is deferred:
>>
>> mhi mhi0_IPCR: Driver qcom_mhi_qrtr force probe deferral
>>
>> The reason for deferring device creation is explained in dpm_prepare():
>>
>>          /*
>>           * It is unsafe if probing of devices will happen during suspend or
>>           * hibernation and system behavior will be unpredictable in this case.
>>           * So, let's prohibit device's probing here and defer their probes
>>           * instead. The normal behavior will be restored in dpm_complete().
>>           */
>>
>> Because the device probe is deferred, the qcom_mhi_qrtr_probe() is not
>> called and thus MHI channels are not prepared:
>>
>> So what this means that QRTR is not delivering messages and the QMI connection
>> is not working between ath11k and the firmware, resulting a failure in firmware
>> initialization.
>>
>> To fix this add new function mhi_power_down_keep_dev() which doesn't destroy
>> the devices for channels during power down. This way we avoid probe defer issue
>> and finally can get ath11k hibernation working with the following patches.
>>
>> Tested-on: WCN6855 hw2.0 PCI WLAN.HSP.1.1-03125-QCAHSPSWPL_V1_V2_SILICONZ_LITE-3.6510.30
>>
>> Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>
> 
> Did Kalle co-author this patch? If so, his Co-developed-by tag should be
> added.
Hmm, I'm not sure...  I would like Kalle's thoughts on this.

> 
>> Signed-off-by: Baochen Qiang <quic_bqiang@quicinc.com>
> 
> Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
> 
> - Mani
> 
>> ---
>>   drivers/bus/mhi/host/internal.h |  4 +++-
>>   drivers/bus/mhi/host/pm.c       | 42 ++++++++++++++++++++++++++++-----
>>   include/linux/mhi.h             | 18 +++++++++++++-
>>   3 files changed, 56 insertions(+), 8 deletions(-)
>>
>> diff --git a/drivers/bus/mhi/host/internal.h b/drivers/bus/mhi/host/internal.h
>> index 5fe49311b8eb..aaad40a07f69 100644
>> --- a/drivers/bus/mhi/host/internal.h
>> +++ b/drivers/bus/mhi/host/internal.h
>> @@ -80,6 +80,7 @@ enum dev_st_transition {
>>   	DEV_ST_TRANSITION_FP,
>>   	DEV_ST_TRANSITION_SYS_ERR,
>>   	DEV_ST_TRANSITION_DISABLE,
>> +	DEV_ST_TRANSITION_DISABLE_DESTROY_DEVICE,
>>   	DEV_ST_TRANSITION_MAX,
>>   };
>>   
>> @@ -90,7 +91,8 @@ enum dev_st_transition {
>>   	dev_st_trans(MISSION_MODE,	"MISSION MODE")		\
>>   	dev_st_trans(FP,		"FLASH PROGRAMMER")	\
>>   	dev_st_trans(SYS_ERR,		"SYS ERROR")		\
>> -	dev_st_trans_end(DISABLE,	"DISABLE")
>> +	dev_st_trans(DISABLE,		"DISABLE")		\
>> +	dev_st_trans_end(DISABLE_DESTROY_DEVICE, "DISABLE (DESTROY DEVICE)")
>>   
>>   extern const char * const dev_state_tran_str[DEV_ST_TRANSITION_MAX];
>>   #define TO_DEV_STATE_TRANS_STR(state) (((state) >= DEV_ST_TRANSITION_MAX) ? \
>> diff --git a/drivers/bus/mhi/host/pm.c b/drivers/bus/mhi/host/pm.c
>> index 8b40d3f01acc..11c0e751f223 100644
>> --- a/drivers/bus/mhi/host/pm.c
>> +++ b/drivers/bus/mhi/host/pm.c
>> @@ -468,7 +468,8 @@ static int mhi_pm_mission_mode_transition(struct mhi_controller *mhi_cntrl)
>>   }
>>   
>>   /* Handle shutdown transitions */
>> -static void mhi_pm_disable_transition(struct mhi_controller *mhi_cntrl)
>> +static void mhi_pm_disable_transition(struct mhi_controller *mhi_cntrl,
>> +				      bool destroy_device)
>>   {
>>   	enum mhi_pm_state cur_state;
>>   	struct mhi_event *mhi_event;
>> @@ -530,8 +531,16 @@ static void mhi_pm_disable_transition(struct mhi_controller *mhi_cntrl)
>>   	dev_dbg(dev, "Waiting for all pending threads to complete\n");
>>   	wake_up_all(&mhi_cntrl->state_event);
>>   
>> -	dev_dbg(dev, "Reset all active channels and remove MHI devices\n");
>> -	device_for_each_child(&mhi_cntrl->mhi_dev->dev, NULL, mhi_destroy_device);
>> +	/*
>> +	 * Only destroy the 'struct device' for channels if indicated by the
>> +	 * 'destroy_device' flag. Because, during system suspend or hibernation
>> +	 * state, there is no need to destroy the 'struct device' as the endpoint
>> +	 * device would still be physically attached to the machine.
>> +	 */
>> +	if (destroy_device) {
>> +		dev_dbg(dev, "Reset all active channels and remove MHI devices\n");
>> +		device_for_each_child(&mhi_cntrl->mhi_dev->dev, NULL, mhi_destroy_device);
>> +	}
>>   
>>   	mutex_lock(&mhi_cntrl->pm_mutex);
>>   
>> @@ -821,7 +830,10 @@ void mhi_pm_st_worker(struct work_struct *work)
>>   			mhi_pm_sys_error_transition(mhi_cntrl);
>>   			break;
>>   		case DEV_ST_TRANSITION_DISABLE:
>> -			mhi_pm_disable_transition(mhi_cntrl);
>> +			mhi_pm_disable_transition(mhi_cntrl, false);
>> +			break;
>> +		case DEV_ST_TRANSITION_DISABLE_DESTROY_DEVICE:
>> +			mhi_pm_disable_transition(mhi_cntrl, true);
>>   			break;
>>   		default:
>>   			break;
>> @@ -1175,7 +1187,8 @@ int mhi_async_power_up(struct mhi_controller *mhi_cntrl)
>>   }
>>   EXPORT_SYMBOL_GPL(mhi_async_power_up);
>>   
>> -void mhi_power_down(struct mhi_controller *mhi_cntrl, bool graceful)
>> +static void __mhi_power_down(struct mhi_controller *mhi_cntrl, bool graceful,
>> +			     bool destroy_device)
>>   {
>>   	enum mhi_pm_state cur_state, transition_state;
>>   	struct device *dev = &mhi_cntrl->mhi_dev->dev;
>> @@ -1211,15 +1224,32 @@ void mhi_power_down(struct mhi_controller *mhi_cntrl, bool graceful)
>>   	write_unlock_irq(&mhi_cntrl->pm_lock);
>>   	mutex_unlock(&mhi_cntrl->pm_mutex);
>>   
>> -	mhi_queue_state_transition(mhi_cntrl, DEV_ST_TRANSITION_DISABLE);
>> +	if (destroy_device)
>> +		mhi_queue_state_transition(mhi_cntrl,
>> +					   DEV_ST_TRANSITION_DISABLE_DESTROY_DEVICE);
>> +	else
>> +		mhi_queue_state_transition(mhi_cntrl,
>> +					   DEV_ST_TRANSITION_DISABLE);
>>   
>>   	/* Wait for shutdown to complete */
>>   	flush_work(&mhi_cntrl->st_worker);
>>   
>>   	disable_irq(mhi_cntrl->irq[0]);
>>   }
>> +
>> +void mhi_power_down(struct mhi_controller *mhi_cntrl, bool graceful)
>> +{
>> +	__mhi_power_down(mhi_cntrl, graceful, true);
>> +}
>>   EXPORT_SYMBOL_GPL(mhi_power_down);
>>   
>> +void mhi_power_down_keep_dev(struct mhi_controller *mhi_cntrl,
>> +			       bool graceful)
>> +{
>> +	__mhi_power_down(mhi_cntrl, graceful, false);
>> +}
>> +EXPORT_SYMBOL_GPL(mhi_power_down_keep_dev);
>> +
>>   int mhi_sync_power_up(struct mhi_controller *mhi_cntrl)
>>   {
>>   	int ret = mhi_async_power_up(mhi_cntrl);
>> diff --git a/include/linux/mhi.h b/include/linux/mhi.h
>> index 77b8c0a26674..cde01e133a1b 100644
>> --- a/include/linux/mhi.h
>> +++ b/include/linux/mhi.h
>> @@ -630,12 +630,28 @@ int mhi_async_power_up(struct mhi_controller *mhi_cntrl);
>>   int mhi_sync_power_up(struct mhi_controller *mhi_cntrl);
>>   
>>   /**
>> - * mhi_power_down - Start MHI power down sequence
>> + * mhi_power_down - Power down the MHI device and also destroy the
>> + *                  'struct device' for the channels associated with it.
>> + *                  See also mhi_power_down_keep_dev() which is a variant
>> + *                  of this API that keeps the 'struct device' for channels
>> + *                  (useful during suspend/hibernation).
>>    * @mhi_cntrl: MHI controller
>>    * @graceful: Link is still accessible, so do a graceful shutdown process
>>    */
>>   void mhi_power_down(struct mhi_controller *mhi_cntrl, bool graceful);
>>   
>> +/**
>> + * mhi_power_down_keep_dev - Power down the MHI device but keep the 'struct
>> + *                           device' for the channels associated with it.
>> + *                           This is a variant of 'mhi_power_down()' and
>> + *                           useful in scenarios such as suspend/hibernation
>> + *                           where destroying of the 'struct device' is not
>> + *                           needed.
>> + * @mhi_cntrl: MHI controller
>> + * @graceful: Link is still accessible, so do a graceful shutdown process
>> + */
>> +void mhi_power_down_keep_dev(struct mhi_controller *mhi_cntrl, bool graceful);
>> +
>>   /**
>>    * mhi_unprepare_after_power_down - Free any allocated memory after power down
>>    * @mhi_cntrl: MHI controller
>> -- 
>> 2.25.1
>>
>
Kalle Valo Feb. 29, 2024, 7:35 p.m. UTC | #4
Baochen Qiang <quic_bqiang@quicinc.com> writes:

> On 2/29/2024 6:12 PM, Manivannan Sadhasivam wrote:
>> On Wed, Feb 28, 2024 at 10:22:41AM +0800, Baochen Qiang wrote:
>>> ath11k fails to resume:
>>>
>>> ath11k_pci 0000:06:00.0: timeout while waiting for restart complete
>>>
>>> This happens because when calling mhi_sync_power_up() the MHI subsystem
>>> eventually calls device_add() from mhi_create_devices() but the device
>>> creation is deferred:
>>>
>>> mhi mhi0_IPCR: Driver qcom_mhi_qrtr force probe deferral
>>>
>>> The reason for deferring device creation is explained in dpm_prepare():
>>>
>>>          /*
>>>           * It is unsafe if probing of devices will happen during suspend or
>>>           * hibernation and system behavior will be unpredictable in this case.
>>>           * So, let's prohibit device's probing here and defer their probes
>>>           * instead. The normal behavior will be restored in dpm_complete().
>>>           */
>>>
>>> Because the device probe is deferred, the qcom_mhi_qrtr_probe() is not
>>> called and thus MHI channels are not prepared:
>>>
>>> So what this means that QRTR is not delivering messages and the QMI connection
>>> is not working between ath11k and the firmware, resulting a failure in firmware
>>> initialization.
>>>
>>> To fix this add new function mhi_power_down_keep_dev() which doesn't destroy
>>> the devices for channels during power down. This way we avoid probe defer issue
>>> and finally can get ath11k hibernation working with the following patches.
>>>
>>> Tested-on: WCN6855 hw2.0 PCI WLAN.HSP.1.1-03125-QCAHSPSWPL_V1_V2_SILICONZ_LITE-3.6510.30
>>>
>>> Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>
>>
>> Did Kalle co-author this patch? If so, his Co-developed-by tag should
>> be added.
>
> Hmm, I'm not sure...  I would like Kalle's thoughts on this.

IIRC I did only some simple cleanup before submitting the patch so I
don't think Co-developed-by is justified. I'm also fine with removing my
Signed-off-by.
Baochen Qiang March 1, 2024, 2:04 a.m. UTC | #5
On 3/1/2024 3:35 AM, Kalle Valo wrote:
> Baochen Qiang <quic_bqiang@quicinc.com> writes:
> 
>> On 2/29/2024 6:12 PM, Manivannan Sadhasivam wrote:
>>> On Wed, Feb 28, 2024 at 10:22:41AM +0800, Baochen Qiang wrote:
>>>> ath11k fails to resume:
>>>>
>>>> ath11k_pci 0000:06:00.0: timeout while waiting for restart complete
>>>>
>>>> This happens because when calling mhi_sync_power_up() the MHI subsystem
>>>> eventually calls device_add() from mhi_create_devices() but the device
>>>> creation is deferred:
>>>>
>>>> mhi mhi0_IPCR: Driver qcom_mhi_qrtr force probe deferral
>>>>
>>>> The reason for deferring device creation is explained in dpm_prepare():
>>>>
>>>>           /*
>>>>            * It is unsafe if probing of devices will happen during suspend or
>>>>            * hibernation and system behavior will be unpredictable in this case.
>>>>            * So, let's prohibit device's probing here and defer their probes
>>>>            * instead. The normal behavior will be restored in dpm_complete().
>>>>            */
>>>>
>>>> Because the device probe is deferred, the qcom_mhi_qrtr_probe() is not
>>>> called and thus MHI channels are not prepared:
>>>>
>>>> So what this means that QRTR is not delivering messages and the QMI connection
>>>> is not working between ath11k and the firmware, resulting a failure in firmware
>>>> initialization.
>>>>
>>>> To fix this add new function mhi_power_down_keep_dev() which doesn't destroy
>>>> the devices for channels during power down. This way we avoid probe defer issue
>>>> and finally can get ath11k hibernation working with the following patches.
>>>>
>>>> Tested-on: WCN6855 hw2.0 PCI WLAN.HSP.1.1-03125-QCAHSPSWPL_V1_V2_SILICONZ_LITE-3.6510.30
>>>>
>>>> Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>
>>>
>>> Did Kalle co-author this patch? If so, his Co-developed-by tag should
>>> be added.
>>
>> Hmm, I'm not sure...  I would like Kalle's thoughts on this.
> 
> IIRC I did only some simple cleanup before submitting the patch so I
> don't think Co-developed-by is justified. I'm also fine with removing my
> Signed-off-by.
Thanks Kalle.

Hi Mani, so according to Kalle's comments, I'd like to keep the patch as is.

>
Manivannan Sadhasivam March 1, 2024, 12:25 p.m. UTC | #6
On Fri, Mar 01, 2024 at 10:04:06AM +0800, Baochen Qiang wrote:
> 
> 
> On 3/1/2024 3:35 AM, Kalle Valo wrote:
> > Baochen Qiang <quic_bqiang@quicinc.com> writes:
> > 
> > > On 2/29/2024 6:12 PM, Manivannan Sadhasivam wrote:
> > > > On Wed, Feb 28, 2024 at 10:22:41AM +0800, Baochen Qiang wrote:
> > > > > ath11k fails to resume:
> > > > > 
> > > > > ath11k_pci 0000:06:00.0: timeout while waiting for restart complete
> > > > > 
> > > > > This happens because when calling mhi_sync_power_up() the MHI subsystem
> > > > > eventually calls device_add() from mhi_create_devices() but the device
> > > > > creation is deferred:
> > > > > 
> > > > > mhi mhi0_IPCR: Driver qcom_mhi_qrtr force probe deferral
> > > > > 
> > > > > The reason for deferring device creation is explained in dpm_prepare():
> > > > > 
> > > > >           /*
> > > > >            * It is unsafe if probing of devices will happen during suspend or
> > > > >            * hibernation and system behavior will be unpredictable in this case.
> > > > >            * So, let's prohibit device's probing here and defer their probes
> > > > >            * instead. The normal behavior will be restored in dpm_complete().
> > > > >            */
> > > > > 
> > > > > Because the device probe is deferred, the qcom_mhi_qrtr_probe() is not
> > > > > called and thus MHI channels are not prepared:
> > > > > 
> > > > > So what this means that QRTR is not delivering messages and the QMI connection
> > > > > is not working between ath11k and the firmware, resulting a failure in firmware
> > > > > initialization.
> > > > > 
> > > > > To fix this add new function mhi_power_down_keep_dev() which doesn't destroy
> > > > > the devices for channels during power down. This way we avoid probe defer issue
> > > > > and finally can get ath11k hibernation working with the following patches.
> > > > > 
> > > > > Tested-on: WCN6855 hw2.0 PCI WLAN.HSP.1.1-03125-QCAHSPSWPL_V1_V2_SILICONZ_LITE-3.6510.30
> > > > > 
> > > > > Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>
> > > > 
> > > > Did Kalle co-author this patch? If so, his Co-developed-by tag should
> > > > be added.
> > > 
> > > Hmm, I'm not sure...  I would like Kalle's thoughts on this.
> > 
> > IIRC I did only some simple cleanup before submitting the patch so I
> > don't think Co-developed-by is justified. I'm also fine with removing my
> > Signed-off-by.
> Thanks Kalle.
> 
> Hi Mani, so according to Kalle's comments, I'd like to keep the patch as is.
> 

No. Either remove his signed off by (as indicated by Kalle) or add a
co-developed-by tag. Keeping just a signed-off-by tag is wrong.

- Mani
Baochen Qiang March 4, 2024, 2:01 a.m. UTC | #7
On 3/1/2024 8:25 PM, Manivannan Sadhasivam wrote:
> On Fri, Mar 01, 2024 at 10:04:06AM +0800, Baochen Qiang wrote:
>>
>>
>> On 3/1/2024 3:35 AM, Kalle Valo wrote:
>>> Baochen Qiang <quic_bqiang@quicinc.com> writes:
>>>
>>>> On 2/29/2024 6:12 PM, Manivannan Sadhasivam wrote:
>>>>> On Wed, Feb 28, 2024 at 10:22:41AM +0800, Baochen Qiang wrote:
>>>>>> ath11k fails to resume:
>>>>>>
>>>>>> ath11k_pci 0000:06:00.0: timeout while waiting for restart complete
>>>>>>
>>>>>> This happens because when calling mhi_sync_power_up() the MHI subsystem
>>>>>> eventually calls device_add() from mhi_create_devices() but the device
>>>>>> creation is deferred:
>>>>>>
>>>>>> mhi mhi0_IPCR: Driver qcom_mhi_qrtr force probe deferral
>>>>>>
>>>>>> The reason for deferring device creation is explained in dpm_prepare():
>>>>>>
>>>>>>            /*
>>>>>>             * It is unsafe if probing of devices will happen during suspend or
>>>>>>             * hibernation and system behavior will be unpredictable in this case.
>>>>>>             * So, let's prohibit device's probing here and defer their probes
>>>>>>             * instead. The normal behavior will be restored in dpm_complete().
>>>>>>             */
>>>>>>
>>>>>> Because the device probe is deferred, the qcom_mhi_qrtr_probe() is not
>>>>>> called and thus MHI channels are not prepared:
>>>>>>
>>>>>> So what this means that QRTR is not delivering messages and the QMI connection
>>>>>> is not working between ath11k and the firmware, resulting a failure in firmware
>>>>>> initialization.
>>>>>>
>>>>>> To fix this add new function mhi_power_down_keep_dev() which doesn't destroy
>>>>>> the devices for channels during power down. This way we avoid probe defer issue
>>>>>> and finally can get ath11k hibernation working with the following patches.
>>>>>>
>>>>>> Tested-on: WCN6855 hw2.0 PCI WLAN.HSP.1.1-03125-QCAHSPSWPL_V1_V2_SILICONZ_LITE-3.6510.30
>>>>>>
>>>>>> Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>
>>>>>
>>>>> Did Kalle co-author this patch? If so, his Co-developed-by tag should
>>>>> be added.
>>>>
>>>> Hmm, I'm not sure...  I would like Kalle's thoughts on this.
>>>
>>> IIRC I did only some simple cleanup before submitting the patch so I
>>> don't think Co-developed-by is justified. I'm also fine with removing my
>>> Signed-off-by.
>> Thanks Kalle.
>>
>> Hi Mani, so according to Kalle's comments, I'd like to keep the patch as is.
>>
> 
> No. Either remove his signed off by (as indicated by Kalle) or add a
> co-developed-by tag. Keeping just a signed-off-by tag is wrong.
> 
OK, will send new version with Kalle's s-o-b tag removed.

> - Mani
>
diff mbox series

Patch

diff --git a/drivers/bus/mhi/host/internal.h b/drivers/bus/mhi/host/internal.h
index 5fe49311b8eb..aaad40a07f69 100644
--- a/drivers/bus/mhi/host/internal.h
+++ b/drivers/bus/mhi/host/internal.h
@@ -80,6 +80,7 @@  enum dev_st_transition {
 	DEV_ST_TRANSITION_FP,
 	DEV_ST_TRANSITION_SYS_ERR,
 	DEV_ST_TRANSITION_DISABLE,
+	DEV_ST_TRANSITION_DISABLE_DESTROY_DEVICE,
 	DEV_ST_TRANSITION_MAX,
 };
 
@@ -90,7 +91,8 @@  enum dev_st_transition {
 	dev_st_trans(MISSION_MODE,	"MISSION MODE")		\
 	dev_st_trans(FP,		"FLASH PROGRAMMER")	\
 	dev_st_trans(SYS_ERR,		"SYS ERROR")		\
-	dev_st_trans_end(DISABLE,	"DISABLE")
+	dev_st_trans(DISABLE,		"DISABLE")		\
+	dev_st_trans_end(DISABLE_DESTROY_DEVICE, "DISABLE (DESTROY DEVICE)")
 
 extern const char * const dev_state_tran_str[DEV_ST_TRANSITION_MAX];
 #define TO_DEV_STATE_TRANS_STR(state) (((state) >= DEV_ST_TRANSITION_MAX) ? \
diff --git a/drivers/bus/mhi/host/pm.c b/drivers/bus/mhi/host/pm.c
index 8b40d3f01acc..11c0e751f223 100644
--- a/drivers/bus/mhi/host/pm.c
+++ b/drivers/bus/mhi/host/pm.c
@@ -468,7 +468,8 @@  static int mhi_pm_mission_mode_transition(struct mhi_controller *mhi_cntrl)
 }
 
 /* Handle shutdown transitions */
-static void mhi_pm_disable_transition(struct mhi_controller *mhi_cntrl)
+static void mhi_pm_disable_transition(struct mhi_controller *mhi_cntrl,
+				      bool destroy_device)
 {
 	enum mhi_pm_state cur_state;
 	struct mhi_event *mhi_event;
@@ -530,8 +531,16 @@  static void mhi_pm_disable_transition(struct mhi_controller *mhi_cntrl)
 	dev_dbg(dev, "Waiting for all pending threads to complete\n");
 	wake_up_all(&mhi_cntrl->state_event);
 
-	dev_dbg(dev, "Reset all active channels and remove MHI devices\n");
-	device_for_each_child(&mhi_cntrl->mhi_dev->dev, NULL, mhi_destroy_device);
+	/*
+	 * Only destroy the 'struct device' for channels if indicated by the
+	 * 'destroy_device' flag. Because, during system suspend or hibernation
+	 * state, there is no need to destroy the 'struct device' as the endpoint
+	 * device would still be physically attached to the machine.
+	 */
+	if (destroy_device) {
+		dev_dbg(dev, "Reset all active channels and remove MHI devices\n");
+		device_for_each_child(&mhi_cntrl->mhi_dev->dev, NULL, mhi_destroy_device);
+	}
 
 	mutex_lock(&mhi_cntrl->pm_mutex);
 
@@ -821,7 +830,10 @@  void mhi_pm_st_worker(struct work_struct *work)
 			mhi_pm_sys_error_transition(mhi_cntrl);
 			break;
 		case DEV_ST_TRANSITION_DISABLE:
-			mhi_pm_disable_transition(mhi_cntrl);
+			mhi_pm_disable_transition(mhi_cntrl, false);
+			break;
+		case DEV_ST_TRANSITION_DISABLE_DESTROY_DEVICE:
+			mhi_pm_disable_transition(mhi_cntrl, true);
 			break;
 		default:
 			break;
@@ -1175,7 +1187,8 @@  int mhi_async_power_up(struct mhi_controller *mhi_cntrl)
 }
 EXPORT_SYMBOL_GPL(mhi_async_power_up);
 
-void mhi_power_down(struct mhi_controller *mhi_cntrl, bool graceful)
+static void __mhi_power_down(struct mhi_controller *mhi_cntrl, bool graceful,
+			     bool destroy_device)
 {
 	enum mhi_pm_state cur_state, transition_state;
 	struct device *dev = &mhi_cntrl->mhi_dev->dev;
@@ -1211,15 +1224,32 @@  void mhi_power_down(struct mhi_controller *mhi_cntrl, bool graceful)
 	write_unlock_irq(&mhi_cntrl->pm_lock);
 	mutex_unlock(&mhi_cntrl->pm_mutex);
 
-	mhi_queue_state_transition(mhi_cntrl, DEV_ST_TRANSITION_DISABLE);
+	if (destroy_device)
+		mhi_queue_state_transition(mhi_cntrl,
+					   DEV_ST_TRANSITION_DISABLE_DESTROY_DEVICE);
+	else
+		mhi_queue_state_transition(mhi_cntrl,
+					   DEV_ST_TRANSITION_DISABLE);
 
 	/* Wait for shutdown to complete */
 	flush_work(&mhi_cntrl->st_worker);
 
 	disable_irq(mhi_cntrl->irq[0]);
 }
+
+void mhi_power_down(struct mhi_controller *mhi_cntrl, bool graceful)
+{
+	__mhi_power_down(mhi_cntrl, graceful, true);
+}
 EXPORT_SYMBOL_GPL(mhi_power_down);
 
+void mhi_power_down_keep_dev(struct mhi_controller *mhi_cntrl,
+			       bool graceful)
+{
+	__mhi_power_down(mhi_cntrl, graceful, false);
+}
+EXPORT_SYMBOL_GPL(mhi_power_down_keep_dev);
+
 int mhi_sync_power_up(struct mhi_controller *mhi_cntrl)
 {
 	int ret = mhi_async_power_up(mhi_cntrl);
diff --git a/include/linux/mhi.h b/include/linux/mhi.h
index 77b8c0a26674..cde01e133a1b 100644
--- a/include/linux/mhi.h
+++ b/include/linux/mhi.h
@@ -630,12 +630,28 @@  int mhi_async_power_up(struct mhi_controller *mhi_cntrl);
 int mhi_sync_power_up(struct mhi_controller *mhi_cntrl);
 
 /**
- * mhi_power_down - Start MHI power down sequence
+ * mhi_power_down - Power down the MHI device and also destroy the
+ *                  'struct device' for the channels associated with it.
+ *                  See also mhi_power_down_keep_dev() which is a variant
+ *                  of this API that keeps the 'struct device' for channels
+ *                  (useful during suspend/hibernation).
  * @mhi_cntrl: MHI controller
  * @graceful: Link is still accessible, so do a graceful shutdown process
  */
 void mhi_power_down(struct mhi_controller *mhi_cntrl, bool graceful);
 
+/**
+ * mhi_power_down_keep_dev - Power down the MHI device but keep the 'struct
+ *                           device' for the channels associated with it.
+ *                           This is a variant of 'mhi_power_down()' and
+ *                           useful in scenarios such as suspend/hibernation
+ *                           where destroying of the 'struct device' is not
+ *                           needed.
+ * @mhi_cntrl: MHI controller
+ * @graceful: Link is still accessible, so do a graceful shutdown process
+ */
+void mhi_power_down_keep_dev(struct mhi_controller *mhi_cntrl, bool graceful);
+
 /**
  * mhi_unprepare_after_power_down - Free any allocated memory after power down
  * @mhi_cntrl: MHI controller