From ff6c4a6449793e9718ef2e9ad46864b63022648e Mon Sep 17 00:00:00 2001
From: Sean Wang <sean.wang@mediatek.com>
Date: Thu, 21 Jul 2022 06:25:37 +0800
Subject: [PATCH] wifi: mt76: mt7921e: fix race issue between reset and
 suspend/resume
Git-commit: ff6c4a6449793e9718ef2e9ad46864b63022648e
References: git-fixes
Patch-mainline: v6.1-rc1

It is unexpected that the reset work is running simultaneously with
the suspend or resume context and it is possible that reset work is still
running even after mt7921 is suspended if we don't fix the race issue.

Thus, the suspend procedure should be waiting until the reset is completed
at the beginning and ignore the subsequent the reset requests.

In case there is an error that happens during either suspend or resume
handler, we will schedule a reset task to recover the error before
returning the error code to ensure we can immediately fix the error there.

Fixes: 0c1ce9884607 ("mt76: mt7921: add wifi reset support")
Co-developed-by: YN Chen <YN.Chen@mediatek.com>
Signed-off-by: YN Chen <YN.Chen@mediatek.com>
Signed-off-by: Sean Wang <sean.wang@mediatek.com>
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Signed-off-by: Oliver Neukum <oneukum@suse.com>
---
 drivers/net/wireless/mediatek/mt76/mt7921/mac.c |    5 +++++
 drivers/net/wireless/mediatek/mt76/mt7921/pci.c |   13 +++++++++----
 2 files changed, 14 insertions(+), 4 deletions(-)

--- a/drivers/net/wireless/mediatek/mt76/mt7921/mac.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7921/mac.c
@@ -1448,6 +1448,7 @@ void mt7921_mac_reset_work(struct work_s
 void mt7921_reset(struct mt76_dev *mdev)
 {
 	struct mt7921_dev *dev = container_of(mdev, struct mt7921_dev, mt76);
+	struct mt76_connac_pm *pm = &dev->pm;
 
 	if (!dev->hw_init_done)
 		return;
@@ -1455,8 +1456,12 @@ void mt7921_reset(struct mt76_dev *mdev)
 	if (dev->hw_full_reset)
 		return;
 
+	if (pm->suspended)
+		return;
+
 	queue_work(dev->mt76.wq, &dev->reset_work);
 }
+EXPORT_SYMBOL_GPL(mt7921_reset);
 
 static void
 mt7921_mac_update_mib_stats(struct mt7921_phy *phy)
--- a/drivers/net/wireless/mediatek/mt76/mt7921/pci.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7921/pci.c
@@ -317,6 +317,7 @@ static int mt7921_pci_suspend(struct pci
 	int i, err;
 
 	pm->suspended = true;
+	flush_work(&dev->reset_work);
 	cancel_delayed_work_sync(&pm->ps_work);
 	cancel_work_sync(&pm->wake_work);
 
@@ -386,6 +387,9 @@ restore_napi:
 restore_suspend:
 	pm->suspended = false;
 
+	if (err < 0)
+		mt7921_reset(&dev->mt76);
+
 	return err;
 }
 
@@ -404,7 +408,7 @@ static int mt7921_pci_resume(struct pci_
 
 	err = mt7921_mcu_drv_pmctrl(dev);
 	if (err < 0)
-		return err;
+		goto failed;
 
 	mt7921_wpdma_reinit_cond(dev);
 
@@ -433,11 +437,12 @@ static int mt7921_pci_resume(struct pci_
 	if (!test_bit(MT76_STATE_SUSPEND, &dev->mphy.state))
 		err = mt76_connac_mcu_set_hif_suspend(mdev, false);
 
-	if (err)
-		return err;
-
+failed:
 	pm->suspended = false;
 
+	if (err < 0)
+		mt7921_reset(&dev->mt76);
+
 	return err;
 }
 #endif /* CONFIG_PM */