net: ethernet: mtk_eth_soc: fix PPE hanging issue

[ Upstream commit ea80e3ed09ab2c2b75724faf5484721753e92c31 ]

A patch to resolve an issue was found in MediaTek's GPL-licensed SDK:
In the mtk_ppe_stop() function, the PPE scan mode is not disabled before
disabling the PPE. This can potentially lead to a hang during the process
of disabling the PPE.

Without this patch, the PPE may experience a hang during the reboot test.

Link: https://git01.mediatek.com/plugins/gitiles/openwrt/feeds/mtk-openwrt-feeds/+/b40da332dfe763932a82f9f62a4709457a15dd6c
Fixes: ba37b7caf1ed ("net: ethernet: mtk_eth_soc: add support for initializing the PPE")
Suggested-by: Bc-bocun Chen <bc-bocun.chen@mediatek.com>
Signed-off-by: Daniel Golle <daniel@makrotopia.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/net/ethernet/mediatek/mtk_ppe.c b/drivers/net/ethernet/mediatek/mtk_ppe.c
index b2a5d9c3733d4823a977cd635d67e707286e9f50..6ce0db3a1a920857016c17b7e7bc4be1f2045a0f 100644 (file)
--- a/drivers/net/ethernet/mediatek/mtk_ppe.c
+++ b/drivers/net/ethernet/mediatek/mtk_ppe.c
@@ -994,7 +994,7 @@ void mtk_ppe_start(struct mtk_ppe *ppe)
                         MTK_PPE_KEEPALIVE_DISABLE) |
              FIELD_PREP(MTK_PPE_TB_CFG_HASH_MODE, 1) |
              FIELD_PREP(MTK_PPE_TB_CFG_SCAN_MODE,
-                        MTK_PPE_SCAN_MODE_KEEPALIVE_AGE) |
+                        MTK_PPE_SCAN_MODE_CHECK_AGE) |
              FIELD_PREP(MTK_PPE_TB_CFG_ENTRY_NUM,
                         MTK_PPE_ENTRIES_SHIFT);
        if (mtk_is_netsys_v2_or_greater(ppe->eth))
@@ -1090,17 +1090,21 @@ int mtk_ppe_stop(struct mtk_ppe *ppe)
 
        mtk_ppe_cache_enable(ppe, false);
 
-       /* disable offload engine */
-       ppe_clear(ppe, MTK_PPE_GLO_CFG, MTK_PPE_GLO_CFG_EN);
-       ppe_w32(ppe, MTK_PPE_FLOW_CFG, 0);
-
        /* disable aging */
        val = MTK_PPE_TB_CFG_AGE_NON_L4 |
              MTK_PPE_TB_CFG_AGE_UNBIND |
              MTK_PPE_TB_CFG_AGE_TCP |
              MTK_PPE_TB_CFG_AGE_UDP |
-             MTK_PPE_TB_CFG_AGE_TCP_FIN;
+             MTK_PPE_TB_CFG_AGE_TCP_FIN |
+                 MTK_PPE_TB_CFG_SCAN_MODE;
        ppe_clear(ppe, MTK_PPE_TB_CFG, val);
 
-       return mtk_ppe_wait_busy(ppe);
+       if (mtk_ppe_wait_busy(ppe))
+               return -ETIMEDOUT;
+
+       /* disable offload engine */
+       ppe_clear(ppe, MTK_PPE_GLO_CFG, MTK_PPE_GLO_CFG_EN);
+       ppe_w32(ppe, MTK_PPE_FLOW_CFG, 0);
+
+       return 0;
 }