[PATCH 05/18] wifi: mt76: mt7925: skip CLR_OWN in mt7925e_mcu_init for MT7927

[Javier Tia]

On MT7927 hardware, every CLR_OWN triggers the ROM bootloader to
reinitialize the WFDMA engine, destroying all DMA ring configuration
(base addresses, prefetch settings, descriptor pointers).

The DMA rings are already properly initialized by mt7927_dma_init()
which performs a controlled CLR_OWN before ring setup. Skip the
SET_OWN/CLR_OWN cycle in mt7925e_mcu_init() to preserve that
configuration.

Tested-by: Marcin FM <marcin at lgic.pl>
Tested-by: Cristian-Florin Radoi <radoi.chris at gmail.com>
Tested-by: George Salukvadze <giosal90 at gmail.com>
Tested-by: Evgeny Kapusta <3193631 at gmail.com>
Tested-by: Samu Toljamo <samu.toljamo at gmail.com>
Tested-by: Ariel Rosenfeld <ariel.rosenfeld.750 at gmail.com>
Tested-by: Chapuis Dario <chapuisdario4 at gmail.com>
Tested-by: Thibaut François <tibo at humeurlibre.fr>
Tested-by: 张旭涵 <Loong.0x00 at gmail.com>
Signed-off-by: Javier Tia <floss at jetm.me>
---
 drivers/net/wireless/mediatek/mt76/mt7925/pci_mcu.c | 19 +++++++++++++------
 1 file changed, 13 insertions(+), 6 deletions(-)

diff --git a/drivers/net/wireless/mediatek/mt76/mt7925/pci_mcu.c b/drivers/net/wireless/mediatek/mt76/mt7925/pci_mcu.c
index 6cceff88c656..206d525eb550 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7925/pci_mcu.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7925/pci_mcu.c
@@ -35,13 +35,20 @@ int mt7925e_mcu_init(struct mt792x_dev *dev)
 
 	dev->mt76.mcu_ops = &mt7925_mcu_ops;
 
-	err = mt792xe_mcu_fw_pmctrl(dev);
-	if (err)
-		return err;
+	if (is_mt7927(&dev->mt76)) {
+		/* MT7927: CLR_OWN was already done in mt7927_dma_init().
+		 * The ROM re-initializes WFDMA on every CLR_OWN, wiping
+		 * ring and prefetch config. Skip SET_OWN/CLR_OWN here
+		 * to preserve DMA state. */
+	} else {
+		err = mt792xe_mcu_fw_pmctrl(dev);
+		if (err)
+			return err;
 
-	err = __mt792xe_mcu_drv_pmctrl(dev);
-	if (err)
-		return err;
+		err = __mt792xe_mcu_drv_pmctrl(dev);
+		if (err)
+			return err;
+	}
 
 	mt76_rmw_field(dev, MT_PCIE_MAC_PM, MT_PCIE_MAC_PM_L0S_DIS, 1);
 

-- 
2.53.0