net: ethernet: ti: cpsw: fix cpts irq after suspend

Depending on the SoC/platform the CPSW can completely lose context after a
suspend/resume cycle, including CPSW wrapper (WR) which will cause reset of
WR_C0_MISC_EN register, so CPTS IRQ will became disabled.

Fix it by moving CPTS IRQ enabling in cpsw_ndo_open() where CPTS is
actually started.

Fixes: 84ea9c0 ("net: ethernet: ti: cpsw: enable cpts irq")
Reported-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Tested-by: Tony Lindgren <tony@atomide.com>
Link: https://lore.kernel.org/r/20201112111546.20343-1-grygorii.strashko@ti.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/ti/cpsw.c

@@ -838,9 +838,12 @@ static int cpsw_ndo_open(struct net_device *ndev)
 		if (ret < 0)
 			goto err_cleanup;
 
-		if (cpts_register(cpsw->cpts))
-			dev_err(priv->dev, "error registering cpts device\n");
-
+		if (cpsw->cpts) {
+			if (cpts_register(cpsw->cpts))
+				dev_err(priv->dev, "error registering cpts device\n");
+			else
+				writel(0x10, &cpsw->wr_regs->misc_en);
+		}
 	}
 
 	cpsw_restore(priv);
@@ -1716,7 +1719,6 @@ static int cpsw_probe(struct platform_device *pdev)
 
 	/* Enable misc CPTS evnt_pend IRQ */
 	cpts_set_irqpoll(cpsw->cpts, false);
-	writel(0x10, &cpsw->wr_regs->misc_en);
 
 skip_cpts:
 	cpsw_notice(priv, probe,

drivers/net/ethernet/ti/cpsw_new.c

@@ -873,8 +873,12 @@ static int cpsw_ndo_open(struct net_device *ndev)
 		if (ret < 0)
 			goto err_cleanup;
 
-		if (cpts_register(cpsw->cpts))
-			dev_err(priv->dev, "error registering cpts device\n");
+		if (cpsw->cpts) {
+			if (cpts_register(cpsw->cpts))
+				dev_err(priv->dev, "error registering cpts device\n");
+			else
+				writel(0x10, &cpsw->wr_regs->misc_en);
+		}
 
 		napi_enable(&cpsw->napi_rx);
 		napi_enable(&cpsw->napi_tx);
@@ -2006,7 +2010,6 @@ static int cpsw_probe(struct platform_device *pdev)
 
 	/* Enable misc CPTS evnt_pend IRQ */
 	cpts_set_irqpoll(cpsw->cpts, false);
-	writel(0x10, &cpsw->wr_regs->misc_en);
 
 skip_cpts:
 	ret = cpsw_register_notifiers(cpsw);