[PATCH 06/11] wifi: mt76: mt792x: add PSE handling barrier for the large MCU cmd

[sean.wang@kernel.org]

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

Add a dummy register read in mt76_connac_mcu_rate_txpower_band() to act as
a PSE barrier. This would release PSE pages and prevents buffer underflow
issues when handling MCU commands with larger payloads without the response
in mt76_connac_mcu_set_rate_txpower().

This is a prerequisite patch before enabling MT7902 PCIe and SDIO support.

Co-developed-by: Xiong Huang <xiong.huang@mediatek.com>
Signed-off-by: Xiong Huang <xiong.huang@mediatek.com>
Signed-off-by: Sean Wang <sean.wang@mediatek.com>
---
 drivers/net/wireless/mediatek/mt76/mt76_connac_mcu.c | 4 ++++
 drivers/net/wireless/mediatek/mt76/mt792x_regs.h     | 2 ++
 2 files changed, 6 insertions(+)

diff --git a/drivers/net/wireless/mediatek/mt76/mt76_connac_mcu.c b/drivers/net/wireless/mediatek/mt76/mt76_connac_mcu.c
index d7fbf3454bb8..89bd52ea8bf7 100644
--- a/drivers/net/wireless/mediatek/mt76/mt76_connac_mcu.c
+++ b/drivers/net/wireless/mediatek/mt76/mt76_connac_mcu.c
@@ -4,6 +4,7 @@
 #include <linux/firmware.h>
 #include "mt76_connac2_mac.h"
 #include "mt76_connac_mcu.h"
+#include "mt792x_regs.h"
 
 int mt76_connac_mcu_start_firmware(struct mt76_dev *dev, u32 addr, u32 option)
 {
@@ -2246,6 +2247,9 @@ mt76_connac_mcu_rate_txpower_band(struct mt76_phy *phy,
 					    false);
 		if (err < 0)
 			goto out;
+
+		/* read a CR to avoid PSE buffer underflow */
+		mt76_connac_mcu_reg_rr(dev, MT_PSE_BASE);
 	}
 
 out:
diff --git a/drivers/net/wireless/mediatek/mt76/mt792x_regs.h b/drivers/net/wireless/mediatek/mt76/mt792x_regs.h
index acf627aed609..7ddde9286861 100644
--- a/drivers/net/wireless/mediatek/mt76/mt792x_regs.h
+++ b/drivers/net/wireless/mediatek/mt76/mt792x_regs.h
@@ -25,6 +25,8 @@
 #define MT_PLE_AC_QEMPTY(_n)		MT_PLE(0x500 + 0x40 * (_n))
 #define MT_PLE_AMSDU_PACK_MSDU_CNT(n)	MT_PLE(0x10e0 + ((n) << 2))
 
+#define MT_PSE_BASE			0x820c8000
+
 /* TMAC: band 0(0x21000), band 1(0xa1000) */
 #define MT_WF_TMAC_BASE(_band)		((_band) ? 0x820f4000 : 0x820e4000)
 #define MT_WF_TMAC(_band, ofs)		(MT_WF_TMAC_BASE(_band) + (ofs))
-- 
2.43.0