[PATCH ath-next 4/5] wifi: ath12k: reorder group start/stop for safe thermal sysfs cleanup

[Maharaja Kennadyrajan]

A later change adds thermal cooling device sysfs under the wiphy device kobject.
With the current teardown order, MAC/wiphy are unregistered before per-device
cleanup, so any subsequent thermal sysfs removal would run after the wiphy kobject
is gone. That ordering is asymmetric with setup and would risk kernfs issues during
removal.

This change also adjusts the position of ath12k_mac_mlo_teardown(). Previously
it ran before per-device cleanup/MAC unregister. MLO teardown issues WMI to teardown
multi-link state and is part of the MAC teardown sequence. Placing it alongside
MAC unregister (after per-device cleanup) preserves setup/teardown symmetry and
avoids racing with remaining netdev/wiphy state.

Reorder hw_group_stop() so per-device cleanup (including thermal/hwmon sysfs
removal) runs while the wiphy still exists. After per-device cleanup completes,
unregister the MAC (dropping wiphys), run ath12k_mac_mlo_teardown(), and finally
destroy the MAC. This mirrors the setup sequence and keeps sysfs cleanup safe
when introduced in a later patch.

To keep start/stop symmetry, add ath12k_core_device_setup() to encapsulate the
per-device bring-up steps (pdev create, IRQ enable, rfkill config) that were
previously open-coded in hw_group_start(). Use this helper in hw_group_start()
to match the existing per-device cleanup helper used by hw_group_stop().

Note that set_bit(ATH12K_FLAG_REGISTERED, &ab->dev_flags) is now executed outside
the ab->core_lock critical section. The core_lock has not provided protection for
the REGISTERED flag, readers do not rely on core_lock for this bit, and the flag
is only toggled in the serialized group start/stop path using atomic bitops.

Tested-on: QCN9274 hw2.0 PCI WLAN.WBE.1.6-01243-QCAHKSWPL_SILICONZ-1

Signed-off-by: Maharaja Kennadyrajan <maharaja.kennadyrajan at oss.qualcomm.com>
---
 drivers/net/wireless/ath/ath12k/core.c | 50 +++++++++++++++-----------
 1 file changed, 29 insertions(+), 21 deletions(-)

diff --git a/drivers/net/wireless/ath/ath12k/core.c b/drivers/net/wireless/ath/ath12k/core.c
index c31c47fb5a73..d21db889794a 100644
--- a/drivers/net/wireless/ath/ath12k/core.c
+++ b/drivers/net/wireless/ath/ath12k/core.c
@@ -1006,6 +1006,27 @@ static void ath12k_core_device_cleanup(struct ath12k_base *ab)
 	mutex_unlock(&ab->core_lock);
 }
 
+static int ath12k_core_device_setup(struct ath12k_base *ab)
+{
+	int ret;
+
+	guard(mutex)(&ab->core_lock);
+
+	ret = ath12k_core_pdev_create(ab);
+	if (ret) {
+		ath12k_err(ab, "failed to create pdev core %d\n", ret);
+		return ret;
+	}
+
+	ath12k_hif_irq_enable(ab);
+
+	ret = ath12k_core_rfkill_config(ab);
+	if (ret && ret != -EOPNOTSUPP)
+		return ret;
+
+	return 0;
+}
+
 static void ath12k_core_hw_group_stop(struct ath12k_hw_group *ag)
 {
 	struct ath12k_base *ab;
@@ -1015,10 +1036,6 @@ static void ath12k_core_hw_group_stop(struct ath12k_hw_group *ag)
 
 	clear_bit(ATH12K_GROUP_FLAG_REGISTERED, &ag->flags);
 
-	ath12k_mac_unregister(ag);
-
-	ath12k_mac_mlo_teardown(ag);
-
 	for (i = ag->num_devices - 1; i >= 0; i--) {
 		ab = ag->ab[i];
 		if (!ab)
@@ -1029,6 +1046,12 @@ static void ath12k_core_hw_group_stop(struct ath12k_hw_group *ag)
 		ath12k_core_device_cleanup(ab);
 	}
 
+	/* Unregister MAC (drops wiphys) only after per-device cleanup */
+	ath12k_mac_unregister(ag);
+
+	/* Teardown MLO state after MAC unregister for symmetry */
+	ath12k_mac_mlo_teardown(ag);
+
 	ath12k_mac_destroy(ag);
 }
 
@@ -1165,26 +1188,11 @@ static int ath12k_core_hw_group_start(struct ath12k_hw_group *ag)
 		if (!ab)
 			continue;
 
-		mutex_lock(&ab->core_lock);
-
 		set_bit(ATH12K_FLAG_REGISTERED, &ab->dev_flags);
 
-		ret = ath12k_core_pdev_create(ab);
-		if (ret) {
-			ath12k_err(ab, "failed to create pdev core %d\n", ret);
-			mutex_unlock(&ab->core_lock);
-			goto err;
-		}
-
-		ath12k_hif_irq_enable(ab);
-
-		ret = ath12k_core_rfkill_config(ab);
-		if (ret && ret != -EOPNOTSUPP) {
-			mutex_unlock(&ab->core_lock);
+		ret = ath12k_core_device_setup(ab);
+		if (ret)
 			goto err;
-		}
-
-		mutex_unlock(&ab->core_lock);
 	}
 
 	return 0;
-- 
2.34.1