[PATCH net-next 1/4] ethtool: add two coalesce attributes for CQE mode

[Yufeng Mo <moyufeng@huawei.com>]

Currently, there many drivers who support CQE mode configuration,
some configure it as a fixed when initialized, some provide an
interface to change it by ethtool private flags. In order make it
more generic, add two new 'ETHTOOL_A_COALESCE_USE_CQE_TX' and
'ETHTOOL_A_COALESCE_USE_CQE_RX' coalesce attributes, then these
parameters can be accessed by ethtool netlink coalesce uAPI.

Signed-off-by: Yufeng Mo <moyufeng@huawei.com>
Signed-off-by: Huazhong Tan <tanhuazhong@huawei.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---
 Documentation/networking/ethtool-netlink.rst | 15 +++++++++++++++
 include/linux/ethtool.h                      |  6 +++++-
 include/uapi/linux/ethtool_netlink.h         |  2 ++
 3 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/Documentation/networking/ethtool-netlink.rst b/Documentation/networking/ethtool-netlink.rst
index c690bb3..d9b55b7 100644
--- a/Documentation/networking/ethtool-netlink.rst
+++ b/Documentation/networking/ethtool-netlink.rst
@@ -947,12 +947,25 @@ Kernel response contents:
   ``ETHTOOL_A_COALESCE_TX_USECS_HIGH``         u32     delay (us), high Tx
   ``ETHTOOL_A_COALESCE_TX_MAX_FRAMES_HIGH``    u32     max packets, high Tx
   ``ETHTOOL_A_COALESCE_RATE_SAMPLE_INTERVAL``  u32     rate sampling interval
+  ``ETHTOOL_A_COALESCE_USE_CQE_TX``            bool    timer reset mode, Tx
+  ``ETHTOOL_A_COALESCE_USE_CQE_RX``            bool    timer reset mode, Rx
   ===========================================  ======  =======================
 
 Attributes are only included in reply if their value is not zero or the
 corresponding bit in ``ethtool_ops::supported_coalesce_params`` is set (i.e.
 they are declared as supported by driver).
 
+Timer reset mode (``ETHTOOL_A_COALESCE_USE_CQE_TX`` and
+``ETHTOOL_A_COALESCE_USE_CQE_RX``) controls the interaction between packet
+arrival and the various time based delay parameters. By default timers are
+expected to limit the max delay between any packet arrival/departure and a
+corresponding interrupt. In this mode timer should be started by packet
+arrival (sometimes delivery of previous interrupt) and reset when interrupt
+is delivered.
+Setting the appropriate attribute to 1 will enable ``CQE`` mode, where
+each packet event resets the timer. In this mode timer is used to force
+the interrupt if queue goes idle, while busy queues depend on the packet
+limit to trigger interrupts.
 
 COALESCE_SET
 ============
@@ -985,6 +998,8 @@ Request contents:
   ``ETHTOOL_A_COALESCE_TX_USECS_HIGH``         u32     delay (us), high Tx
   ``ETHTOOL_A_COALESCE_TX_MAX_FRAMES_HIGH``    u32     max packets, high Tx
   ``ETHTOOL_A_COALESCE_RATE_SAMPLE_INTERVAL``  u32     rate sampling interval
+  ``ETHTOOL_A_COALESCE_USE_CQE_TX``            bool    timer reset mode, Tx
+  ``ETHTOOL_A_COALESCE_USE_CQE_RX``            bool    timer reset mode, Rx
   ===========================================  ======  =======================
 
 Request is rejected if it attributes declared as unsupported by driver (i.e.
diff --git a/include/linux/ethtool.h b/include/linux/ethtool.h
index 4711b96..bad4c7a 100644
--- a/include/linux/ethtool.h
+++ b/include/linux/ethtool.h
@@ -211,7 +211,9 @@ bool ethtool_convert_link_mode_to_legacy_u32(u32 *legacy_u32,
 #define ETHTOOL_COALESCE_TX_USECS_HIGH		BIT(19)
 #define ETHTOOL_COALESCE_TX_MAX_FRAMES_HIGH	BIT(20)
 #define ETHTOOL_COALESCE_RATE_SAMPLE_INTERVAL	BIT(21)
-#define ETHTOOL_COALESCE_ALL_PARAMS		GENMASK(21, 0)
+#define ETHTOOL_COALESCE_USE_CQE_RX		BIT(22)
+#define ETHTOOL_COALESCE_USE_CQE_TX		BIT(23)
+#define ETHTOOL_COALESCE_ALL_PARAMS		GENMASK(23, 0)
 
 #define ETHTOOL_COALESCE_USECS						\
 	(ETHTOOL_COALESCE_RX_USECS | ETHTOOL_COALESCE_TX_USECS)
@@ -237,6 +239,8 @@ bool ethtool_convert_link_mode_to_legacy_u32(u32 *legacy_u32,
 	 ETHTOOL_COALESCE_RX_USECS_LOW | ETHTOOL_COALESCE_RX_USECS_HIGH | \
 	 ETHTOOL_COALESCE_PKT_RATE_LOW | ETHTOOL_COALESCE_PKT_RATE_HIGH | \
 	 ETHTOOL_COALESCE_RATE_SAMPLE_INTERVAL)
+#define ETHTOOL_COALESCE_USE_CQE					\
+	(ETHTOOL_COALESCE_USE_CQE_RX | ETHTOOL_COALESCE_USE_CQE_TX)
 
 #define ETHTOOL_STAT_NOT_SET	(~0ULL)
 
diff --git a/include/uapi/linux/ethtool_netlink.h b/include/uapi/linux/ethtool_netlink.h
index b3b9371..5545f1c 100644
--- a/include/uapi/linux/ethtool_netlink.h
+++ b/include/uapi/linux/ethtool_netlink.h
@@ -377,6 +377,8 @@ enum {
 	ETHTOOL_A_COALESCE_TX_USECS_HIGH,		/* u32 */
 	ETHTOOL_A_COALESCE_TX_MAX_FRAMES_HIGH,		/* u32 */
 	ETHTOOL_A_COALESCE_RATE_SAMPLE_INTERVAL,	/* u32 */
+	ETHTOOL_A_COALESCE_USE_CQE_MODE_TX,		/* u8 */
+	ETHTOOL_A_COALESCE_USE_CQE_MODE_RX,		/* u8 */
 
 	/* add new constants above here */
 	__ETHTOOL_A_COALESCE_CNT,
-- 
2.8.1