Re: [PATCH v6] bus: mhi: host: don't free bhie tables during suspend/hibernation

[Muhammad Usama Anjum <usama.anjum@collabora.com>]

Hi,

Reminder

On 5/28/25 10:25 AM, Muhammad Usama Anjum wrote:
> Soft reminder
> 
> On 5/16/25 11:49 PM, Muhammad Usama Anjum wrote:
>> Fix dma_direct_alloc() failure at resume time during bhie_table
>> allocation because of memory pressure. There is a report where at
>> resume time, the memory from the dma doesn't get allocated and MHI
>> fails to re-initialize.
>>
>> To fix it, don't free the memory at power down during suspend /
>> hibernation. Instead, use the same allocated memory again after every
>> resume / hibernation. This patch has been tested with resume and
>> hibernation both.
>>
>> Optimize the rddm and fbc bhie allocations. The rddm is of constant
>> size for a given hardware. While the fbc_image size depends on the
>> firmware. If the firmware changes, we'll free and allocate new memory
>> for it. This patch is motivated from the ath12k [1] and ath11k [2]
>> patches. They don't free the memory and reuse the same memory if new
>> size is same. The firmware caching hasn't been implemented for the
>> drivers other than in the nouveau. (The changing of firmware isn't
>> tested/supported for wireless drivers. But let's follow the example
>> patches here.)
>>
>> [1] https://lore.kernel.org/all/20240419034034.2842-1-quic_bqiang@quicinc.com/
>> [2] https://lore.kernel.org/all/20220506141448.10340-1-quic_akolli@quicinc.com/
>>
>> Tested-on: WCN6855 WLAN.HSP.1.1-03926.13-QCAHSPSWPL_V2_SILICONZ_CE-2.52297.6
>> Tested-on: WCN7850 hw2.0 WLAN.HMT.1.1.c5-00284-QCAHMTSWPL_V1.0_V2.0_SILICONZ-3
>>
>> Acked-by: Jeff Johnson <jeff.johnson@oss.qualcomm.com>
>> Tested-by: Baochen Qiang <quic_bqiang@quicinc.com>
>> Signed-off-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
>> ---
>> Changes since v1:
>> - Don't free bhie tables during suspend/hibernation only
>> - Handle fbc_image changed size correctly
>> - Remove fbc_image getting set to NULL in *free_bhie_table()
>>
>> Changes since v2:
>> - Remove the new mhi_partial_unprepare_after_power_down() and instead
>>   update mhi_power_down_keep_dev() to use
>>   mhi_power_down_unprepare_keep_dev() as suggested by Mani
>> - Update all users of this API such as ath12k (previously only ath11k
>>   was updated)
>> - Define prev_fw_sz in docs
>> - Do better alignment of comments
>>
>> Changes since v3:
>> - Fix state machine of ath12k by setting ATH12K_MHI_DEINIT with
>>   ATH12K_MHI_POWER_OFF_KEEP_DEV state (Thanks Sebastian for testing and
>>   finding the problem)
>> - Use static with mhi_power_down_unprepare_keep_dev()
>> - Remove crash log as it was showing that kworker wasn't able to
>>   allocate memory.
>>
>> Changes since v4:
>> - Update description
>> - Use __mhi_power_down_unprepare_keep_dev() in
>>   mhi_unprepare_after_power_down()
>>
>> Changes since v5:
>> - Update description to don't give an impression that all bhie
>>   allocations are being fixed. mhi_load_image_bhie() doesn't require
>>   this optimization.
>>
>> This patch doesn't have fixes tag as we are avoiding error in case of
>> memory pressure. We are just making this driver more robust by not
>> freeing the memory and using the same after resuming.
>> ---
>>  drivers/bus/mhi/host/boot.c           | 15 +++++++++++----
>>  drivers/bus/mhi/host/init.c           | 18 ++++++++++++------
>>  drivers/bus/mhi/host/internal.h       |  2 ++
>>  drivers/bus/mhi/host/pm.c             |  1 +
>>  drivers/net/wireless/ath/ath11k/mhi.c |  8 ++++----
>>  drivers/net/wireless/ath/ath12k/mhi.c | 14 ++++++++++----
>>  include/linux/mhi.h                   |  2 ++
>>  7 files changed, 42 insertions(+), 18 deletions(-)
>>
>> diff --git a/drivers/bus/mhi/host/boot.c b/drivers/bus/mhi/host/boot.c
>> index efa3b6dddf4d2..bc8459798bbee 100644
>> --- a/drivers/bus/mhi/host/boot.c
>> +++ b/drivers/bus/mhi/host/boot.c
>> @@ -584,10 +584,17 @@ void mhi_fw_load_handler(struct mhi_controller *mhi_cntrl)
>>  	 * device transitioning into MHI READY state
>>  	 */
>>  	if (fw_load_type == MHI_FW_LOAD_FBC) {
>> -		ret = mhi_alloc_bhie_table(mhi_cntrl, &mhi_cntrl->fbc_image, fw_sz);
>> -		if (ret) {
>> -			release_firmware(firmware);
>> -			goto error_fw_load;
>> +		if (mhi_cntrl->fbc_image && fw_sz != mhi_cntrl->prev_fw_sz) {
>> +			mhi_free_bhie_table(mhi_cntrl, mhi_cntrl->fbc_image);
>> +			mhi_cntrl->fbc_image = NULL;
>> +		}
>> +		if (!mhi_cntrl->fbc_image) {
>> +			ret = mhi_alloc_bhie_table(mhi_cntrl, &mhi_cntrl->fbc_image, fw_sz);
>> +			if (ret) {
>> +				release_firmware(firmware);
>> +				goto error_fw_load;
>> +			}
>> +			mhi_cntrl->prev_fw_sz = fw_sz;
>>  		}
>>  
>>  		/* Load the firmware into BHIE vec table */
>> diff --git a/drivers/bus/mhi/host/init.c b/drivers/bus/mhi/host/init.c
>> index 13e7a55f54ff4..8419ea8a5419b 100644
>> --- a/drivers/bus/mhi/host/init.c
>> +++ b/drivers/bus/mhi/host/init.c
>> @@ -1173,8 +1173,9 @@ int mhi_prepare_for_power_up(struct mhi_controller *mhi_cntrl)
>>  		/*
>>  		 * Allocate RDDM table for debugging purpose if specified
>>  		 */
>> -		mhi_alloc_bhie_table(mhi_cntrl, &mhi_cntrl->rddm_image,
>> -				     mhi_cntrl->rddm_size);
>> +		if (!mhi_cntrl->rddm_image)
>> +			mhi_alloc_bhie_table(mhi_cntrl, &mhi_cntrl->rddm_image,
>> +					     mhi_cntrl->rddm_size);
>>  		if (mhi_cntrl->rddm_image) {
>>  			ret = mhi_rddm_prepare(mhi_cntrl,
>>  					       mhi_cntrl->rddm_image);
>> @@ -1200,6 +1201,14 @@ int mhi_prepare_for_power_up(struct mhi_controller *mhi_cntrl)
>>  }
>>  EXPORT_SYMBOL_GPL(mhi_prepare_for_power_up);
>>  
>> +void __mhi_unprepare_keep_dev(struct mhi_controller *mhi_cntrl)
>> +{
>> +	mhi_cntrl->bhi = NULL;
>> +	mhi_cntrl->bhie = NULL;
>> +
>> +	mhi_deinit_dev_ctxt(mhi_cntrl);
>> +}
>> +
>>  void mhi_unprepare_after_power_down(struct mhi_controller *mhi_cntrl)
>>  {
>>  	if (mhi_cntrl->fbc_image) {
>> @@ -1212,10 +1221,7 @@ void mhi_unprepare_after_power_down(struct mhi_controller *mhi_cntrl)
>>  		mhi_cntrl->rddm_image = NULL;
>>  	}
>>  
>> -	mhi_cntrl->bhi = NULL;
>> -	mhi_cntrl->bhie = NULL;
>> -
>> -	mhi_deinit_dev_ctxt(mhi_cntrl);
>> +	__mhi_unprepare_keep_dev(mhi_cntrl);
>>  }
>>  EXPORT_SYMBOL_GPL(mhi_unprepare_after_power_down);
>>  
>> diff --git a/drivers/bus/mhi/host/internal.h b/drivers/bus/mhi/host/internal.h
>> index ce566f7d2e924..41b3fb835880b 100644
>> --- a/drivers/bus/mhi/host/internal.h
>> +++ b/drivers/bus/mhi/host/internal.h
>> @@ -427,4 +427,6 @@ void mhi_unmap_single_no_bb(struct mhi_controller *mhi_cntrl,
>>  void mhi_unmap_single_use_bb(struct mhi_controller *mhi_cntrl,
>>  			     struct mhi_buf_info *buf_info);
>>  
>> +void __mhi_unprepare_keep_dev(struct mhi_controller *mhi_cntrl);
>> +
>>  #endif /* _MHI_INT_H */
>> diff --git a/drivers/bus/mhi/host/pm.c b/drivers/bus/mhi/host/pm.c
>> index e6c3ff62bab1d..c2c09c308b9b7 100644
>> --- a/drivers/bus/mhi/host/pm.c
>> +++ b/drivers/bus/mhi/host/pm.c
>> @@ -1263,6 +1263,7 @@ void mhi_power_down_keep_dev(struct mhi_controller *mhi_cntrl,
>>  			       bool graceful)
>>  {
>>  	__mhi_power_down(mhi_cntrl, graceful, false);
>> +	__mhi_unprepare_keep_dev(mhi_cntrl);
>>  }
>>  EXPORT_SYMBOL_GPL(mhi_power_down_keep_dev);
>>  
>> diff --git a/drivers/net/wireless/ath/ath11k/mhi.c b/drivers/net/wireless/ath/ath11k/mhi.c
>> index acd76e9392d31..c5dc776b23643 100644
>> --- a/drivers/net/wireless/ath/ath11k/mhi.c
>> +++ b/drivers/net/wireless/ath/ath11k/mhi.c
>> @@ -460,12 +460,12 @@ void ath11k_mhi_stop(struct ath11k_pci *ab_pci, bool is_suspend)
>>  	 * workaround, otherwise ath11k_core_resume() will timeout
>>  	 * during resume.
>>  	 */
>> -	if (is_suspend)
>> +	if (is_suspend) {
>>  		mhi_power_down_keep_dev(ab_pci->mhi_ctrl, true);
>> -	else
>> +	} else {
>>  		mhi_power_down(ab_pci->mhi_ctrl, true);
>> -
>> -	mhi_unprepare_after_power_down(ab_pci->mhi_ctrl);
>> +		mhi_unprepare_after_power_down(ab_pci->mhi_ctrl);
>> +	}
>>  }
>>  
>>  int ath11k_mhi_suspend(struct ath11k_pci *ab_pci)
>> diff --git a/drivers/net/wireless/ath/ath12k/mhi.c b/drivers/net/wireless/ath/ath12k/mhi.c
>> index 08f44baf182a5..3af524ccf4a5a 100644
>> --- a/drivers/net/wireless/ath/ath12k/mhi.c
>> +++ b/drivers/net/wireless/ath/ath12k/mhi.c
>> @@ -601,6 +601,12 @@ static int ath12k_mhi_set_state(struct ath12k_pci *ab_pci,
>>  
>>  	ath12k_mhi_set_state_bit(ab_pci, mhi_state);
>>  
>> +	/* mhi_power_down_keep_dev() has been updated to DEINIT without
>> +	 * freeing bhie tables
>> +	 */
>> +	if (mhi_state == ATH12K_MHI_POWER_OFF_KEEP_DEV)
>> +		ath12k_mhi_set_state_bit(ab_pci, ATH12K_MHI_DEINIT);
>> +
>>  	return 0;
>>  
>>  out:
>> @@ -635,12 +641,12 @@ void ath12k_mhi_stop(struct ath12k_pci *ab_pci, bool is_suspend)
>>  	 * workaround, otherwise ath12k_core_resume() will timeout
>>  	 * during resume.
>>  	 */
>> -	if (is_suspend)
>> +	if (is_suspend) {
>>  		ath12k_mhi_set_state(ab_pci, ATH12K_MHI_POWER_OFF_KEEP_DEV);
>> -	else
>> +	} else {
>>  		ath12k_mhi_set_state(ab_pci, ATH12K_MHI_POWER_OFF);
>> -
>> -	ath12k_mhi_set_state(ab_pci, ATH12K_MHI_DEINIT);
>> +		ath12k_mhi_set_state(ab_pci, ATH12K_MHI_DEINIT);
>> +	}
>>  }
>>  
>>  void ath12k_mhi_suspend(struct ath12k_pci *ab_pci)
>> diff --git a/include/linux/mhi.h b/include/linux/mhi.h
>> index dd372b0123a6d..6fd218a877855 100644
>> --- a/include/linux/mhi.h
>> +++ b/include/linux/mhi.h
>> @@ -306,6 +306,7 @@ struct mhi_controller_config {
>>   *           if fw_image is NULL and fbc_download is true (optional)
>>   * @fw_sz: Firmware image data size for normal booting, used only if fw_image
>>   *         is NULL and fbc_download is true (optional)
>> + * @prev_fw_sz: Previous firmware image data size, when fbc_download is true
>>   * @edl_image: Firmware image name for emergency download mode (optional)
>>   * @rddm_size: RAM dump size that host should allocate for debugging purpose
>>   * @sbl_size: SBL image size downloaded through BHIe (optional)
>> @@ -382,6 +383,7 @@ struct mhi_controller {
>>  	const char *fw_image;
>>  	const u8 *fw_data;
>>  	size_t fw_sz;
>> +	size_t prev_fw_sz;
>>  	const char *edl_image;
>>  	size_t rddm_size;
>>  	size_t sbl_size;
> 
> 


-- 
Regards,
Usama