Re: [PATCH 3/7] mt76: mt7921: fix reset under the deep sleep is enabled

[Lorenzo Bianconi <lorenzo@kernel.org>]

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> From: Sean Wang <sean.wang@mediatek.com>
> 
> To fix possibly the race to access register between the WiFi reset
> and the other context that is caused by explicitly cancelling ps_work
> and wake_work to break PM_STATE consistency.
> 
> Deep sleep would cause the hardware into the inactive state,
> so we forcely put device drv_own state before we start to reset.
> 
> The patch also ignore the reset request when the procedure is in
> progress to avoid the consecutive WiFi resets.
> 
> localhost ~ # [ 2932.073966] SError Interrupt on CPU7, code 0xbe000011
> [ 2932.073967] CPU: 7 PID: 8761 Comm: kworker/u16:2 Not tainted 5.4.112 #30
> [ 2932.073968] Hardware name: MediaTek Asurada rev1 board (DT)
> [ 2932.073968] Workqueue: phy0 ieee80211_reconfig_filter [mac80211]
> [ 2932.073969] pstate: 80400089 (Nzcv daIf +PAN -UAO)
> [ 2932.073969] pc : el1_irq+0x78/0x180
> [ 2932.073970] lr : mt76_mmio_rmw+0x30/0x5c [mt76]
> [ 2932.073970] sp : ffffffc01142bad0
> [ 2932.073970] x29: ffffffc01142bc00 x28: ffffff8f96fb1e00
> [ 2932.073971] x27: ffffffd2cdc12138 x26: ffffffd2cdaeb018
> [ 2932.073972] x25: 0000000000000000 x24: ffffff8fa8e14c08
> [ 2932.073973] x23: 0000000080c00009 x22: ffffffd2a5603918
> [ 2932.073974] x21: ffffffc01142bc10 x20: 0000007fffffffff
> [ 2932.073975] x19: 0000000000000000 x18: 0000000000000400
> [ 2932.073975] x17: 0000000000000400 x16: ffffffd2cd2b87dc
> [ 2932.073976] x15: 0000000000000000 x14: 0000000000000000
> [ 2932.073977] x13: 0000000000000001 x12: 0000000000000001
> [ 2932.073978] x11: 0000000000000001 x10: 000000000010e000
> [ 2932.073978] x9 : 0000000000000000 x8 : ffffffc013921404
> [ 2932.073979] x7 : 000000b2b5593519 x6 : 0000000000300000
> [ 2932.073980] x5 : 0000000000000000 x4 : ffffffc01142bbc8
> [ 2932.073980] x3 : 00000000000001f0 x2 : 0000000000000000
> [ 2932.073981] x1 : 0000000000021404 x0 : ffffff8fa8e12300
> [ 2932.073982] Kernel panic - not syncing: Asynchronous SError Interrupt
> [ 2932.073983] CPU: 7 PID: 8761 Comm: kworker/u16:2 Not tainted 5.4.112 #30
> [ 2932.073983] Hardware name: MediaTek Asurada rev1 board (DT)
> [ 2932.073984] Workqueue: phy0 ieee80211_reconfig_filter [mac80211]
> [ 2932.073984] Call trace:
> [ 2932.073985]  dump_backtrace+0x0/0x14c
> [ 2932.073985]  show_stack+0x20/0x2c
> [ 2932.073985]  dump_stack+0xa0/0xf8
> [ 2932.073986]  panic+0x154/0x360
> [ 2932.073986]  test_taint+0x0/0x44
> [ 2932.073986]  arm64_serror_panic+0x78/0x84
> [ 2932.073987]  do_serror+0x0/0x118
> [ 2932.073987]  do_serror+0xa4/0x118
> [ 2932.073987]  el1_error+0x84/0xf8
> [ 2932.073988]  el1_irq+0x78/0x180
> [ 2932.073988]  mt76_mmio_rr+0x30/0xf0 [mt76]
> [ 2932.073988]  mt76_mmio_rmw+0x30/0x5c [mt76]
> [ 2932.073989]  mt7921_rmw+0x4c/0x5c [mt7921e]
> [ 2932.073989]  mt7921_configure_filter+0x138/0x160 [mt7921e]
> [ 2932.073990]  ieee80211_configure_filter+0x2f0/0x3e0 [mac80211]
> [ 2932.073990]  ieee80211_reconfig_filter+0x1c/0x28 [mac80211]
> [ 2932.073990]  process_one_work+0x208/0x3c8
> [ 2932.073991]  worker_thread+0x23c/0x3e8
> [ 2932.073991]  kthread+0x140/0x17c
> [ 2932.073992]  ret_from_fork+0x10/0x18
> [ 2932.074071] SMP: stopping secondary CPUs
> [ 2932.074071] Kernel Offset: 0x12bc800000 from 0xffffffc010000000
> [ 2932.074072] PHYS_OFFSET: 0xfffffff180000000
> [ 2932.074072] CPU features: 0x080026,2a80aa18
> [ 2932.074072] Memory Limit: none
> 
> Fixes: 87843566e581 ("mt76: mt7921: enable deep sleep at runtime")
> Co-developed-by: Lorenzo Bianconi <lorenzo@kernel.org>
> Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
> Signed-off-by: Sean Wang <sean.wang@mediatek.com>
> ---
>  .../net/wireless/mediatek/mt76/mt7921/mac.c   | 21 +++++++++--------
>  .../net/wireless/mediatek/mt76/mt7921/mcu.c   | 23 ++++++++++++++-----
>  .../wireless/mediatek/mt76/mt7921/mt7921.h    |  1 +
>  3 files changed, 30 insertions(+), 15 deletions(-)
> 
> diff --git a/drivers/net/wireless/mediatek/mt76/mt7921/mac.c b/drivers/net/wireless/mediatek/mt76/mt7921/mac.c
> index e29d4fdab572..ebd365ceb70d 100644
> --- a/drivers/net/wireless/mediatek/mt76/mt7921/mac.c
> +++ b/drivers/net/wireless/mediatek/mt76/mt7921/mac.c
> @@ -1284,9 +1284,10 @@ mt7921_mac_reset(struct mt7921_dev *dev)
>  	mt76_worker_enable(&dev->mt76.tx_worker);
>  
>  	clear_bit(MT76_MCU_RESET, &dev->mphy.state);
> -	clear_bit(MT76_STATE_PM, &dev->mphy.state);
>  
> -	mt76_wr(dev, MT_WFDMA0_HOST_INT_ENA, 0);
> +	mt76_wr(dev, MT_WFDMA0_HOST_INT_ENA,
> +		MT_INT_RX_DONE_ALL | MT_INT_TX_DONE_ALL |
> +		MT_INT_MCU_CMD);
>  	mt76_wr(dev, MT_PCIE_MAC_INT_ENABLE, 0xff);
>  
>  	err = mt7921_run_firmware(dev);
> @@ -1304,22 +1305,23 @@ mt7921_mac_reset(struct mt7921_dev *dev)
>  /* system error recovery */
>  void mt7921_mac_reset_work(struct work_struct *work)
>  {
> -	struct ieee80211_hw *hw;
> -	struct mt7921_dev *dev;
> +	struct mt7921_dev *dev = container_of(work, struct mt7921_dev,
> +					      reset_work);
> +	struct ieee80211_hw *hw = mt76_hw(dev);
> +	struct mt76_connac_pm *pm = &dev->pm;
>  	int i;
>  
> -	dev = container_of(work, struct mt7921_dev, reset_work);
> -	hw = mt76_hw(dev);
> -
>  	dev_err(dev->mt76.dev, "chip reset\n");
>  	ieee80211_stop_queues(hw);
>  
>  	cancel_delayed_work_sync(&dev->mphy.mac_work);
> -	cancel_delayed_work_sync(&dev->pm.ps_work);
> -	cancel_work_sync(&dev->pm.wake_work);
> +	cancel_delayed_work_sync(&pm->ps_work);
> +	cancel_work_sync(&pm->wake_work);
>  
>  	mutex_lock(&dev->mt76.mutex);
>  	for (i = 0; i < 10; i++) {
> +		__mt7921_mcu_drv_pmctrl(dev);
> +
>  		if (!mt7921_mac_reset(dev))
>  			break;
>  	}
> @@ -1340,6 +1342,7 @@ void mt7921_mac_reset_work(struct work_struct *work)
>  	ieee80211_iterate_active_interfaces(hw,
>  					    IEEE80211_IFACE_ITER_RESUME_ALL,
>  					    mt7921_vif_connect_iter, NULL);
> +	mt76_connac_power_save_sched(&dev->mt76.phy, pm);

I guess we should avoid mt7921_vif_connect_iter and
mt76_connac_power_save_sched if hw reset fails, what do you think?

Regards,
Lorenzo

>  }
>  
>  void mt7921_reset(struct mt76_dev *mdev)
> diff --git a/drivers/net/wireless/mediatek/mt76/mt7921/mcu.c b/drivers/net/wireless/mediatek/mt76/mt7921/mcu.c
> index 5a4c695f73c9..486e5593d99a 100644
> --- a/drivers/net/wireless/mediatek/mt76/mt7921/mcu.c
> +++ b/drivers/net/wireless/mediatek/mt76/mt7921/mcu.c
> @@ -1296,17 +1296,12 @@ int mt7921_mcu_sta_add(struct mt7921_dev *dev, struct ieee80211_sta *sta,
>  	return mt76_connac_mcu_add_sta_cmd(&dev->mphy, &info);
>  }
>  
> -int mt7921_mcu_drv_pmctrl(struct mt7921_dev *dev)
> +int __mt7921_mcu_drv_pmctrl(struct mt7921_dev *dev)
>  {
>  	struct mt76_phy *mphy = &dev->mt76.phy;
>  	struct mt76_connac_pm *pm = &dev->pm;
>  	int i, err = 0;
>  
> -	mutex_lock(&pm->mutex);
> -
> -	if (!test_bit(MT76_STATE_PM, &mphy->state))
> -		goto out;
> -
>  	for (i = 0; i < MT7921_DRV_OWN_RETRY_COUNT; i++) {
>  		mt76_wr(dev, MT_CONN_ON_LPCTL, PCIE_LPCR_HOST_CLR_OWN);
>  		if (mt76_poll_msec(dev, MT_CONN_ON_LPCTL,
> @@ -1326,6 +1321,22 @@ int mt7921_mcu_drv_pmctrl(struct mt7921_dev *dev)
>  	pm->stats.last_wake_event = jiffies;
>  	pm->stats.doze_time += pm->stats.last_wake_event -
>  			       pm->stats.last_doze_event;
> +out:
> +	return err;
> +}
> +
> +int mt7921_mcu_drv_pmctrl(struct mt7921_dev *dev)
> +{
> +	struct mt76_phy *mphy = &dev->mt76.phy;
> +	struct mt76_connac_pm *pm = &dev->pm;
> +	int err = 0;
> +
> +	mutex_lock(&pm->mutex);
> +
> +	if (!test_bit(MT76_STATE_PM, &mphy->state))
> +		goto out;
> +
> +	err = __mt7921_mcu_drv_pmctrl(dev);
>  out:
>  	mutex_unlock(&pm->mutex);
>  
> diff --git a/drivers/net/wireless/mediatek/mt76/mt7921/mt7921.h b/drivers/net/wireless/mediatek/mt76/mt7921/mt7921.h
> index 59862ea4951c..03bcb210c357 100644
> --- a/drivers/net/wireless/mediatek/mt76/mt7921/mt7921.h
> +++ b/drivers/net/wireless/mediatek/mt76/mt7921/mt7921.h
> @@ -368,6 +368,7 @@ int mt7921_mcu_uni_bss_bcnft(struct mt7921_dev *dev, struct ieee80211_vif *vif,
>  			     bool enable);
>  int mt7921_mcu_set_bss_pm(struct mt7921_dev *dev, struct ieee80211_vif *vif,
>  			  bool enable);
> +int __mt7921_mcu_drv_pmctrl(struct mt7921_dev *dev);
>  int mt7921_mcu_drv_pmctrl(struct mt7921_dev *dev);
>  int mt7921_mcu_fw_pmctrl(struct mt7921_dev *dev);
>  void mt7921_pm_wake_work(struct work_struct *work);
> -- 
> 2.25.1
> 

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