wifi: mt76: mt7921e: fix random fw download fail

In case of PCIe interoperability problem shows up, the firmware
payload may be corrupted in download stage. Turn off L0s to keep
fw download process accurately.

[ 1093.528363] mt7921e 0000:3b:00.0: Message 00000007 (seq 7) timeout
[ 1093.528414] mt7921e 0000:3b:00.0: Failed to start patch
[ 1096.600156] mt7921e 0000:3b:00.0: Message 00000010 (seq 8) timeout
[ 1096.600207] mt7921e 0000:3b:00.0: Failed to release patch semaphore
[ 1097.699031] mt7921e 0000:3b:00.0: Timeout for driver own
[ 1098.758427] mt7921e 0000:3b:00.0: Timeout for driver own
[ 1099.834408] mt7921e 0000:3b:00.0: Timeout for driver own
[ 1100.915264] mt7921e 0000:3b:00.0: Timeout for driver own
[ 1101.990625] mt7921e 0000:3b:00.0: Timeout for driver own
[ 1103.077587] mt7921e 0000:3b:00.0: Timeout for driver own
[ 1104.173258] mt7921e 0000:3b:00.0: Timeout for driver own
[ 1105.248466] mt7921e 0000:3b:00.0: Timeout for driver own
[ 1106.336969] mt7921e 0000:3b:00.0: Timeout for driver own
[ 1106.397542] mt7921e 0000:3b:00.0: hardware init failed

Cc: stable@vger.kernel.org
Fixes: bf3747ae ("mt76: mt7921: enable aspm by default")
Signed-off-by: Deren Wu <deren.wu@mediatek.com>
Tested-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: Felix Fietkau <nbd@nbd.name>

drivers/net/wireless/mediatek/mt76/mt7921/pci.c

@@ -148,6 +148,7 @@ static u32 __mt7921_reg_addr(struct mt7921_dev *dev, u32 addr)
 		{ 0x820c8000, 0x0c000, 0x02000 }, /* WF_UMAC_TOP (PSE) */
 		{ 0x820cc000, 0x0e000, 0x01000 }, /* WF_UMAC_TOP (PP) */
 		{ 0x820cd000, 0x0f000, 0x01000 }, /* WF_MDP_TOP */
+		{ 0x74030000, 0x10000, 0x10000 }, /* PCIE_MAC_IREG */
 		{ 0x820ce000, 0x21c00, 0x00200 }, /* WF_LMAC_TOP (WF_SEC) */
 		{ 0x820cf000, 0x22000, 0x01000 }, /* WF_LMAC_TOP (WF_PF) */
 		{ 0x820e0000, 0x20000, 0x00400 }, /* WF_LMAC_TOP BN0 (WF_CFG) */

drivers/net/wireless/mediatek/mt76/mt7921/pci_mcu.c

@@ -54,6 +54,8 @@ int mt7921e_mcu_init(struct mt7921_dev *dev)
 	if (err)
 		return err;
 
+	mt76_rmw_field(dev, MT_PCIE_MAC_PM, MT_PCIE_MAC_PM_L0S_DIS, 1);
+
 	err = mt7921_run_firmware(dev);
 
 	mt76_queue_tx_cleanup(dev, dev->mt76.q_mcu[MT_MCUQ_FWDL], false);

drivers/net/wireless/mediatek/mt76/mt7921/regs.h

@@ -440,6 +440,8 @@
 #define MT_PCIE_MAC_BASE		0x10000
 #define MT_PCIE_MAC(ofs)		(MT_PCIE_MAC_BASE + (ofs))
 #define MT_PCIE_MAC_INT_ENABLE		MT_PCIE_MAC(0x188)
+#define MT_PCIE_MAC_PM			MT_PCIE_MAC(0x194)
+#define MT_PCIE_MAC_PM_L0S_DIS		BIT(8)
 
 #define MT_DMA_SHDL(ofs)		(0x7c026000 + (ofs))
 #define MT_DMASHDL_SW_CONTROL		MT_DMA_SHDL(0x004)