[PATCH 5.14 719/849] net: davinci_emac: Fix interrupt pacing disable

Greg Kroah-Hartman
2021-11-15T23:18:17Z

From: Maxim Kiselev <bigunclemax@gmail.com>

[ Upstream commit d52bcb47bdf971a59a2467975d2405fcfcb2fa19 ]

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>
Link: https://lore.kernel.org/r/20211101152343.4193233-1-bigunclemax@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
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 c674e34b68394..399bc92562f42 100644
--- a/drivers/net/ethernet/ti/davinci_emac.c
+++ b/drivers/net/ethernet/ti/davinci_emac.c
@@ -412,8 +412,20 @@ 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;

--
2.33.0