realtek: reset both ethernet NIC and queues

Recent versions of Realtek's SDK reset both the ethernet NIC and queues
(SW_NIC_RST and SW_Q_RST bits) when initialising the hardware.

Furthermore, when issuing a CPU reset on the Zyxel GS1900-8 (not
supported by any current driver), the networking part of the SoC is not
reset. This leads to unresponsive network after the restart. By
resetting both the ethernet NIC and queues, networking always comes up
reliably.

Suggested-by: Birger Koblitz <[email protected]>
Signed-off-by: Sander Vanheule <[email protected]>
Tested-by: Stijn Tintel <[email protected]>

target/linux/realtek/files-5.10/drivers/net/ethernet/rtl838x_eth.c

@@ -630,6 +630,7 @@ static const struct rtl838x_reg rtl931x_reg = {
 static void rtl838x_hw_reset(struct rtl838x_eth_priv *priv)
 {
 	u32 int_saved, nbuf;
+	u32 reset_mask;
 	int i, pos;
 	
 	pr_info("RESETTING %x, CPU_PORT %d\n", priv->family_id, priv->cpu_port);
@@ -662,15 +663,17 @@ static void rtl838x_hw_reset(struct rtl838x_eth_priv *priv)
 		sw_w32(0xffffffff, priv->r->dma_if_intr_sts);
 	}
 
-	/* Reset NIC  */
+	/* Reset NIC (SW_NIC_RST) and queues (SW_Q_RST) */
 	if (priv->family_id == RTL9300_FAMILY_ID || priv->family_id == RTL9310_FAMILY_ID)
-		sw_w32(0x4, priv->r->rst_glb_ctrl);
+		reset_mask = 0x6;
 	else
-		sw_w32(0x8, priv->r->rst_glb_ctrl);
+		reset_mask = 0xc;
+
+	sw_w32(reset_mask, priv->r->rst_glb_ctrl);
 
 	do { /* Wait for reset of NIC and Queues done */
 		udelay(20);
-	} while (sw_r32(priv->r->rst_glb_ctrl) & 0xc);
+	} while (sw_r32(priv->r->rst_glb_ctrl) & reset_mask);
 	mdelay(100);
 
 	/* Setup Head of Line */