[PATCH v2] net: davinci_emac: Fix interrupt pacing disable

From: Maxim Kiselev <bigunclemax@gmail.com>
To: unlisted-recipients:; (no To-header on input)
Cc: Maxim Kiselev <bigunclemax@gmail.com>,
	Grygorii Strashko <grygorii.strashko@ti.com>,
	"David S. Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>,
	Yang Yingliang <yangyingliang@huawei.com>,
	Andrew Lunn <andrew@lunn.ch>,
	Colin Ian King <colin.king@canonical.com>,
	Yufeng Mo <moyufeng@huawei.com>, Michael Walle <michael@walle.cc>,
	Sriram <srk@ti.com>,
	linux-omap@vger.kernel.org, netdev@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: [PATCH v2] net: davinci_emac: Fix interrupt pacing disable
Date: Mon,  1 Nov 2021 18:23:41 +0300	[thread overview]
Message-ID: <20211101152343.4193233-1-bigunclemax@gmail.com> (raw)

This patch allows to use 0 for `coal->rx_coalesce_usecs` param to
disable rx irq coalescing.

Previously we could enable rx irq coalescing via ethtool
(For ex: `ethtool -C eth0 rx-usecs 2000`) but we couldn't disable
it because this part rejects 0 value:

       if (!coal->rx_coalesce_usecs)
               return -EINVAL;

Fixes: 84da2658a619 ("TI DaVinci EMAC : Implement interrupt pacing
functionality.")

Signed-off-by: Maxim Kiselev <bigunclemax@gmail.com>
Reviewed-by: Grygorii Strashko <grygorii.strashko@ti.com>
---
Changes v1 -> v2 (after review of Grygorii Strashko):

 - Simplify !coal->rx_coalesce_usecs handler

---
 drivers/net/ethernet/ti/davinci_emac.c | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/ti/davinci_emac.c b/drivers/net/ethernet/ti/davinci_emac.c
index e8291d8488391..d243ca5dfde00 100644
--- a/drivers/net/ethernet/ti/davinci_emac.c
+++ b/drivers/net/ethernet/ti/davinci_emac.c
@@ -420,8 +420,20 @@ static int emac_set_coalesce(struct net_device *ndev,
 	u32 int_ctrl, num_interrupts = 0;
 	u32 prescale = 0, addnl_dvdr = 1, coal_intvl = 0;
 
-	if (!coal->rx_coalesce_usecs)
-		return -EINVAL;
+	if (!coal->rx_coalesce_usecs) {
+		priv->coal_intvl = 0;
+
+		switch (priv->version) {
+		case EMAC_VERSION_2:
+			emac_ctrl_write(EMAC_DM646X_CMINTCTRL, 0);
+			break;
+		default:
+			emac_ctrl_write(EMAC_CTRL_EWINTTCNT, 0);
+			break;
+		}
+
+		return 0;
+	}
 
 	coal_intvl = coal->rx_coalesce_usecs;
 
-- 
2.30.2

