ethtool: provide coalescing parameters with COALESCE_GET request

Implement COALESCE_GET request to get coalescing parameters of a network
device. These are traditionally available via ETHTOOL_GCOALESCE ioctl
request. This commit adds only support for device coalescing parameters,
not per queue coalescing parameters.

Omit attributes with zero values unless they are declared as supported
(i.e. the corresponding bit in ethtool_ops::supported_coalesce_params is
set).

Signed-off-by: Michal Kubecek <mkubecek@suse.cz>
Reviewed-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 47 insertions, 1 deletions

diff --git a/Documentation/networking/ethtool-netlink.rst b/Documentation/networking/ethtool-netlink.rst
index 31a601cafa3f..1e84686a998b 100644
--- a/Documentation/networking/ethtool-netlink.rst
+++ b/Documentation/networking/ethtool-netlink.rst
@@ -197,6 +197,7 @@ Userspace to kernel:
   ``ETHTOOL_MSG_RINGS_SET``             set ring sizes
   ``ETHTOOL_MSG_CHANNELS_GET``          get channel counts
   ``ETHTOOL_MSG_CHANNELS_SET``          set channel counts
+  ``ETHTOOL_MSG_COALESCE_GET``          get coalescing parameters
   ===================================== ================================
 
 Kernel to userspace:
@@ -221,6 +222,7 @@ Kernel to userspace:
   ``ETHTOOL_MSG_RINGS_NTF``             ring sizes
   ``ETHTOOL_MSG_CHANNELS_GET_REPLY``    channel counts
   ``ETHTOOL_MSG_CHANNELS_NTF``          channel counts
+  ``ETHTOOL_MSG_COALESCE_GET_REPLY``    coalescing parameters
   ===================================== =================================
 
 ``GET`` requests are sent by userspace applications to retrieve device
@@ -745,6 +747,50 @@ driver. Driver may impose additional constraints and may not suspport all
 attributes.
 
 
+COALESCE_GET
+============
+
+Gets coalescing parameters like ``ETHTOOL_GCOALESCE`` ioctl request.
+
+Request contents:
+
+  ====================================  ======  ==========================
+  ``ETHTOOL_A_COALESCE_HEADER``         nested  request header
+  ====================================  ======  ==========================
+
+Kernel response contents:
+
+  ===========================================  ======  =======================
+  ``ETHTOOL_A_COALESCE_HEADER``                nested  reply header
+  ``ETHTOOL_A_COALESCE_RX_USECS``              u32     delay (us), normal Rx
+  ``ETHTOOL_A_COALESCE_RX_MAX_FRAMES``         u32     max packets, normal Rx
+  ``ETHTOOL_A_COALESCE_RX_USECS_IRQ``          u32     delay (us), Rx in IRQ
+  ``ETHTOOL_A_COALESCE_RX_MAX_FRAMES_IRQ``     u32     max packets, Rx in IRQ
+  ``ETHTOOL_A_COALESCE_TX_USECS``              u32     delay (us), normal Tx
+  ``ETHTOOL_A_COALESCE_TX_MAX_FRAMES``         u32     max packets, normal Tx
+  ``ETHTOOL_A_COALESCE_TX_USECS_IRQ``          u32     delay (us), Tx in IRQ
+  ``ETHTOOL_A_COALESCE_TX_MAX_FRAMES_IRQ``     u32     IRQ packets, Tx in IRQ
+  ``ETHTOOL_A_COALESCE_STATS_BLOCK_USECS``     u32     delay of stats update
+  ``ETHTOOL_A_COALESCE_USE_ADAPTIVE_RX``       bool    adaptive Rx coalesce
+  ``ETHTOOL_A_COALESCE_USE_ADAPTIVE_TX``       bool    adaptive Tx coalesce
+  ``ETHTOOL_A_COALESCE_PKT_RATE_LOW``          u32     threshold for low rate
+  ``ETHTOOL_A_COALESCE_RX_USECS_LOW``          u32     delay (us), low Rx
+  ``ETHTOOL_A_COALESCE_RX_MAX_FRAMES_LOW``     u32     max packets, low Rx
+  ``ETHTOOL_A_COALESCE_TX_USECS_LOW``          u32     delay (us), low Tx
+  ``ETHTOOL_A_COALESCE_TX_MAX_FRAMES_LOW``     u32     max packets, low Tx
+  ``ETHTOOL_A_COALESCE_PKT_RATE_HIGH``         u32     threshold for high rate
+  ``ETHTOOL_A_COALESCE_RX_USECS_HIGH``         u32     delay (us), high Rx
+  ``ETHTOOL_A_COALESCE_RX_MAX_FRAMES_HIGH``    u32     max packets, high Rx
+  ``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
+  ===========================================  ======  =======================
+
+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).
+
+
 Request translation
 ===================
 
@@ -769,7 +815,7 @@ have their netlink replacement yet.
   ``ETHTOOL_GLINK``                   ``ETHTOOL_MSG_LINKSTATE_GET``
   ``ETHTOOL_GEEPROM``                 n/a
   ``ETHTOOL_SEEPROM``                 n/a
-  ``ETHTOOL_GCOALESCE``               n/a
+  ``ETHTOOL_GCOALESCE``               ``ETHTOOL_MSG_COALESCE_GET``
   ``ETHTOOL_SCOALESCE``               n/a
   ``ETHTOOL_GRINGPARAM``              ``ETHTOOL_MSG_RINGS_GET``
   ``ETHTOOL_SRINGPARAM``              ``ETHTOOL_MSG_RINGS_SET``