From: Baochen Qiang <quic_bqiang@quicinc.com>
Subject: [PATCH v2 1/3] bus: mhi: host: add mhi_power_down_keep_dev()
Date: Tue, 27 Feb 2024 14:36:11 +0800
Message-ID: <20240227063613.4478-2-quic_bqiang@quicinc.com>
Patch-mainline: Submitted, linux-wireless ML
References: bsc#1207948
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>
Acked-by: Takashi Iwai <tiwai@suse.de>
---
drivers/bus/mhi/host/init.c | 1
drivers/bus/mhi/host/internal.h | 1
drivers/bus/mhi/host/pm.c | 41 ++++++++++++++++++++++++++++++++++------
include/linux/mhi.h | 18 ++++++++++++++++-
4 files changed, 54 insertions(+), 7 deletions(-)
--- 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[DE
[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] = {
--- 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,
};
--- a/drivers/bus/mhi/host/pm.c
+++ b/drivers/bus/mhi/host/pm.c
@@ -458,7 +458,8 @@ error_mission_mode:
}
/* 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 +521,15 @@ skip_mhi_reset:
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);
+ /**
+ * Some MHI controller drivers, ath11k as an example, would like to keep
+ * MHI deivces for channels during suspend/hibernation to avoid the
+ * probe defer issue. Add a check here to make it possible.
+ */
+ 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 +814,10 @@ void mhi_pm_st_worker(struct work_struct
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 +1171,8 @@ error_exit:
}
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;
@@ -1196,15 +1208,32 @@ void mhi_power_down(struct mhi_controlle
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);
--- a/include/linux/mhi.h
+++ b/include/linux/mhi.h
@@ -649,13 +649,29 @@ int mhi_async_power_up(struct mhi_contro
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
*/