On Mon, Nov 27, 2023 at 06:20:15PM +0200, Kalle Valo wrote:
> From: Baochen Qiang <quic_bqiang@xxxxxxxxxxx>
>
> If ath11k tries to call mhi_power_up() during resume it fails:
>
This is confusing! Maybe this is what confused me initially. mhi_sync_power_up()
never fails, but ath11k timesout waiting for QMI. You also confirmed the same
[1].
> ath11k_pci 0000:06:00.0: timeout while waiting for restart complete
>
> This happens because when calling mhi_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
> qcom_mhi_qrtr_dl_callback() fails silently as qdev is zero:
>
> static void qcom_mhi_qrtr_dl_callback(struct mhi_device *mhi_dev,
> struct mhi_result *mhi_res)
> {
> struct qrtr_mhi_dev *qdev = dev_get_drvdata(&mhi_dev->dev);
> int rc;
>
> if (!qdev || mhi_res->transaction_status)
> return;
>
> 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
> initialisation.
>
> To fix this add new function mhi_power_down_no_destroy() which does not destroy
> the devices during power down. This way mhi_power_up() can be called during
> resume and we 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: Baochen Qiang <quic_bqiang@xxxxxxxxxxx>
> Signed-off-by: Kalle Valo <quic_kvalo@xxxxxxxxxxx>
> ---
> drivers/bus/mhi/host/init.c | 1 +
> drivers/bus/mhi/host/internal.h | 1 +
> drivers/bus/mhi/host/pm.c | 26 +++++++++++++++++++-------
> include/linux/mhi.h | 29 +++++++++++++++++++++++++++--
> 4 files changed, 48 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/bus/mhi/host/init.c b/drivers/bus/mhi/host/init.c
> index 65ceac1837f9..e626b03ffafa 100644
> --- a/drivers/bus/mhi/host/init.c
> +++ b/drivers/bus/mhi/host/init.c
> @@ -43,6 +43,7 @@ const char * const dev_state_tran_str[DEV_ST_TRANSITION_MAX] = {
> [DEV_ST_TRANSITION_FP] = "FLASH PROGRAMMER",
> [DEV_ST_TRANSITION_SYS_ERR] = "SYS ERROR",
> [DEV_ST_TRANSITION_DISABLE] = "DISABLE",
> + [DEV_ST_TRANSITION_DISABLE_DESTROY_DEVICE] = "DISABLE (DESTROY DEVICE)",
> };
>
> const char * const mhi_ch_state_type_str[MHI_CH_STATE_TYPE_MAX] = {
> diff --git a/drivers/bus/mhi/host/internal.h b/drivers/bus/mhi/host/internal.h
> index 30ac415a3000..3f45c9c447bd 100644
> --- a/drivers/bus/mhi/host/internal.h
> +++ b/drivers/bus/mhi/host/internal.h
> @@ -69,6 +69,7 @@ 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,
> };
>
> diff --git a/drivers/bus/mhi/host/pm.c b/drivers/bus/mhi/host/pm.c
> index a2f2feef1476..8833b0248393 100644
> --- a/drivers/bus/mhi/host/pm.c
> +++ b/drivers/bus/mhi/host/pm.c
> @@ -458,7 +458,8 @@ 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;
> @@ -520,8 +521,10 @@ 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);
> + 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);
>
> @@ -806,7 +809,10 @@ 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;
> @@ -1160,7 +1166,8 @@ 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)
> +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;
> @@ -1196,14 +1203,19 @@ 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]);
> }
> -EXPORT_SYMBOL_GPL(mhi_power_down);
> +EXPORT_SYMBOL_GPL(__mhi_power_down);
This is a helper, so should not be exported. You should export the API instead.
>
> int mhi_sync_power_up(struct mhi_controller *mhi_cntrl)
> {
> diff --git a/include/linux/mhi.h b/include/linux/mhi.h
> index d0f9b522f328..ae092bc8b97e 100644
> --- a/include/linux/mhi.h
> +++ b/include/linux/mhi.h
> @@ -648,12 +648,37 @@ int mhi_async_power_up(struct mhi_controller *mhi_cntrl);
> */
> int mhi_sync_power_up(struct mhi_controller *mhi_cntrl);
>
> +void __mhi_power_down(struct mhi_controller *mhi_cntrl, bool graceful,
> + bool destroy_device);
This is a helper, so make it static.
> +
> /**
> - * mhi_power_down - Start MHI power down sequence
> + * mhi_power_down - Start MHI power down sequence. See also
> + * mhi_power_down_no_destroy() which is a variant of this for suspend.
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);
> +static inline void mhi_power_down(struct mhi_controller *mhi_cntrl, bool graceful)
No, API cannot be static inline. Make it global.
> +{
> + __mhi_power_down(mhi_cntrl, graceful, true);
> +}
> +
> +/**
> + * mhi_power_down_no_destroy - Start MHI power down sequence but don't
> + * destroy struct devices. This is a variant for mhi_power_down() and is a
"struct devices for channels"
> + * workaround to make it possible to use mhi_power_up() in a resume
You should mention that the devices are not destroyed and this would be useful
in suspend/hibernation.
> + * handler. When using this variant the caller must also call
> + * mhi_prepare_all_for_transfer_autoqueue() and
mhi_prepare_all_for_transfer*()
> + * mhi_unprepare_all_from_transfer().
> + *
> + * @mhi_cntrl: MHI controller
> + * @graceful: Link is still accessible, so do a graceful shutdown process
> + */
> +static inline void mhi_power_down_no_destroy(struct mhi_controller *mhi_cntrl,
> + bool graceful)
Same as above, make it global.
- Mani
--
மணிவண்ணன் சதாசிவம்
