[PATCH 1/2] wifi: mt76: mt792x: add common USB transport reset helpers

[Sean Wang <sean.wang@kernel.org>]

From: Sean Wang <sean.wang@mediatek.com>

Add per-device USB reset work and a control-path access check helper
for mt7921u and mt7925u.

This prepares common infrastructure for transport-level recovery while
keeping the reset state per-device for correct lifetime handling.

No functional change intended.

Signed-off-by: Sean Wang <sean.wang@mediatek.com>
---
 .../net/wireless/mediatek/mt76/mt7921/usb.c   |  2 +
 .../net/wireless/mediatek/mt76/mt7925/usb.c   |  2 +
 drivers/net/wireless/mediatek/mt76/mt792x.h   |  5 ++
 .../net/wireless/mediatek/mt76/mt792x_usb.c   | 50 +++++++++++++++++++
 4 files changed, 59 insertions(+)

diff --git a/drivers/net/wireless/mediatek/mt76/mt7921/usb.c b/drivers/net/wireless/mediatek/mt76/mt7921/usb.c
index 17057e68bf21..6be28f4152ed 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7921/usb.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7921/usb.c
@@ -196,6 +196,7 @@ static int mt7921u_probe(struct usb_interface *usb_intf,
 	dev = container_of(mdev, struct mt792x_dev, mt76);
 	dev->fw_features = features;
 	dev->hif_ops = &hif_ops;
+	mt792xu_reset_work_init(dev);
 
 	udev = usb_get_dev(udev);
 	usb_reset_device(udev);
@@ -244,6 +245,7 @@ static int mt7921u_probe(struct usb_interface *usb_intf,
 
 error:
 	mt76u_queues_deinit(&dev->mt76);
+	mt792xu_reset_work_cleanup(dev);
 
 	usb_set_intfdata(usb_intf, NULL);
 	usb_put_dev(interface_to_usbdev(usb_intf));
diff --git a/drivers/net/wireless/mediatek/mt76/mt7925/usb.c b/drivers/net/wireless/mediatek/mt76/mt7925/usb.c
index d9968f03856d..8b5d58125352 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7925/usb.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7925/usb.c
@@ -184,6 +184,7 @@ static int mt7925u_probe(struct usb_interface *usb_intf,
 	dev = container_of(mdev, struct mt792x_dev, mt76);
 	dev->fw_features = features;
 	dev->hif_ops = &hif_ops;
+	mt792xu_reset_work_init(dev);
 
 	udev = usb_get_dev(udev);
 	usb_reset_device(udev);
@@ -232,6 +233,7 @@ static int mt7925u_probe(struct usb_interface *usb_intf,
 
 error:
 	mt76u_queues_deinit(&dev->mt76);
+	mt792xu_reset_work_cleanup(dev);
 
 	usb_set_intfdata(usb_intf, NULL);
 	usb_put_dev(interface_to_usbdev(usb_intf));
diff --git a/drivers/net/wireless/mediatek/mt76/mt792x.h b/drivers/net/wireless/mediatek/mt76/mt792x.h
index 4ff93f2cd624..5f06074591ca 100644
--- a/drivers/net/wireless/mediatek/mt76/mt792x.h
+++ b/drivers/net/wireless/mediatek/mt76/mt792x.h
@@ -243,6 +243,8 @@ struct mt792x_dev {
 	wait_queue_head_t wait;
 
 	struct work_struct init_work;
+	struct work_struct usb_reset_work;
+	atomic_t usb_reset_pending;
 
 	u8 fw_debug;
 	u8 fw_features;
@@ -489,6 +491,9 @@ int mt792xu_dma_init(struct mt792x_dev *dev, bool resume);
 int mt792xu_mcu_power_on(struct mt792x_dev *dev);
 int mt792xu_wfsys_reset(struct mt792x_dev *dev);
 int mt792xu_init_reset(struct mt792x_dev *dev);
+void mt792xu_reset_work_init(struct mt792x_dev *dev);
+void mt792xu_reset_work_cleanup(struct mt792x_dev *dev);
+int mt792xu_check_bus(struct mt792x_dev *dev);
 u32 mt792xu_rr(struct mt76_dev *dev, u32 addr);
 void mt792xu_wr(struct mt76_dev *dev, u32 addr, u32 val);
 u32 mt792xu_rmw(struct mt76_dev *dev, u32 addr, u32 mask, u32 val);
diff --git a/drivers/net/wireless/mediatek/mt76/mt792x_usb.c b/drivers/net/wireless/mediatek/mt76/mt792x_usb.c
index 47827d1c5ccb..2558d87b1e0f 100644
--- a/drivers/net/wireless/mediatek/mt76/mt792x_usb.c
+++ b/drivers/net/wireless/mediatek/mt76/mt792x_usb.c
@@ -11,6 +11,55 @@
 #include "mt792x.h"
 #include "mt76_connac2_mac.h"
 
+static int mt792xu_read32(struct mt76_dev *dev, u32 addr, void *buf)
+{
+	return __mt76u_vendor_request(dev, MT_VEND_READ_EXT,
+				      USB_DIR_IN | MT_USB_TYPE_VENDOR,
+				      (u16)(addr >> 16), (u16)addr,
+				      buf, sizeof(__le32));
+}
+
+static void mt792xu_reset_work(struct work_struct *work)
+{
+	struct mt792x_dev *dev =
+		container_of(work, struct mt792x_dev, usb_reset_work);
+	struct usb_interface *usb_intf = to_usb_interface(dev->mt76.dev);
+
+	if (usb_intf && usb_get_intfdata(usb_intf) == dev)
+		usb_queue_reset_device(usb_intf);
+
+	atomic_set(&dev->usb_reset_pending, 0);
+}
+
+void mt792xu_reset_work_init(struct mt792x_dev *dev)
+{
+	INIT_WORK(&dev->usb_reset_work, mt792xu_reset_work);
+	atomic_set(&dev->usb_reset_pending, 0);
+}
+EXPORT_SYMBOL_GPL(mt792xu_reset_work_init);
+
+void mt792xu_reset_work_cleanup(struct mt792x_dev *dev)
+{
+	cancel_work_sync(&dev->usb_reset_work);
+	atomic_set(&dev->usb_reset_pending, 0);
+}
+EXPORT_SYMBOL_GPL(mt792xu_reset_work_cleanup);
+
+int mt792xu_check_bus(struct mt792x_dev *dev)
+{
+	int ret;
+
+	mutex_lock(&dev->mt76.usb.usb_ctrl_mtx);
+	ret = mt792xu_read32(&dev->mt76, MT_HW_CHIPID, dev->mt76.usb.data);
+	mutex_unlock(&dev->mt76.usb.usb_ctrl_mtx);
+
+	if (ret == sizeof(__le32))
+		return 0;
+
+	return ret < 0 ? ret : -EIO;
+}
+EXPORT_SYMBOL_GPL(mt792xu_check_bus);
+
 u32 mt792xu_rr(struct mt76_dev *dev, u32 addr)
 {
 	u32 ret;
@@ -333,6 +382,7 @@ void mt792xu_disconnect(struct usb_interface *usb_intf)
 {
 	struct mt792x_dev *dev = usb_get_intfdata(usb_intf);
 
+	mt792xu_reset_work_cleanup(dev);
 	cancel_work_sync(&dev->init_work);
 	if (!test_bit(MT76_STATE_INITIALIZED, &dev->mphy.state))
 		return;
-- 
2.43.0