[PATCH net-next v4 1/8] gve: Add device option for nic clock synchronization

[Harshitha Ramamurthy <hramamurthy@google.com>]

From: John Fraker <jfraker@google.com>

Add the device option and negotiation with the device for clock
synchronization with the nic. This option is necessary before the driver
will advertise support for hardware timestamping or other related
features.

Signed-off-by: Jeff Rogers <jefrogers@google.com>
Signed-off-by: John Fraker <jfraker@google.com>
Signed-off-by: Ziwei Xiao <ziweixiao@google.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Harshitha Ramamurthy <hramamurthy@google.com>
---
 drivers/net/ethernet/google/gve/gve.h        |  3 ++
 drivers/net/ethernet/google/gve/gve_adminq.c | 31 +++++++++++++++++++-
 drivers/net/ethernet/google/gve/gve_adminq.h |  9 ++++++
 3 files changed, 42 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/google/gve/gve.h b/drivers/net/ethernet/google/gve/gve.h
index 2fab38c8ee78..e9b2c1394b1f 100644
--- a/drivers/net/ethernet/google/gve/gve.h
+++ b/drivers/net/ethernet/google/gve/gve.h
@@ -870,6 +870,9 @@ struct gve_priv {
 	u16 rss_lut_size;
 	bool cache_rss_config;
 	struct gve_rss_config rss_config;
+
+	/* True if the device supports reading the nic clock */
+	bool nic_timestamp_supported;
 };
 
 enum gve_service_task_flags_bit {
diff --git a/drivers/net/ethernet/google/gve/gve_adminq.c b/drivers/net/ethernet/google/gve/gve_adminq.c
index 3e8fc33cc11f..ae20d2f7e6e1 100644
--- a/drivers/net/ethernet/google/gve/gve_adminq.c
+++ b/drivers/net/ethernet/google/gve/gve_adminq.c
@@ -46,6 +46,7 @@ void gve_parse_device_option(struct gve_priv *priv,
 			     struct gve_device_option_buffer_sizes **dev_op_buffer_sizes,
 			     struct gve_device_option_flow_steering **dev_op_flow_steering,
 			     struct gve_device_option_rss_config **dev_op_rss_config,
+			     struct gve_device_option_nic_timestamp **dev_op_nic_timestamp,
 			     struct gve_device_option_modify_ring **dev_op_modify_ring)
 {
 	u32 req_feat_mask = be32_to_cpu(option->required_features_mask);
@@ -225,6 +226,23 @@ void gve_parse_device_option(struct gve_priv *priv,
 				 "RSS config");
 		*dev_op_rss_config = (void *)(option + 1);
 		break;
+	case GVE_DEV_OPT_ID_NIC_TIMESTAMP:
+		if (option_length < sizeof(**dev_op_nic_timestamp) ||
+		    req_feat_mask != GVE_DEV_OPT_REQ_FEAT_MASK_NIC_TIMESTAMP) {
+			dev_warn(&priv->pdev->dev, GVE_DEVICE_OPTION_ERROR_FMT,
+				 "Nic Timestamp",
+				 (int)sizeof(**dev_op_nic_timestamp),
+				 GVE_DEV_OPT_REQ_FEAT_MASK_NIC_TIMESTAMP,
+				 option_length, req_feat_mask);
+			break;
+		}
+
+		if (option_length > sizeof(**dev_op_nic_timestamp))
+			dev_warn(&priv->pdev->dev,
+				 GVE_DEVICE_OPTION_TOO_BIG_FMT,
+				 "Nic Timestamp");
+		*dev_op_nic_timestamp = (void *)(option + 1);
+		break;
 	default:
 		/* If we don't recognize the option just continue
 		 * without doing anything.
@@ -246,6 +264,7 @@ gve_process_device_options(struct gve_priv *priv,
 			   struct gve_device_option_buffer_sizes **dev_op_buffer_sizes,
 			   struct gve_device_option_flow_steering **dev_op_flow_steering,
 			   struct gve_device_option_rss_config **dev_op_rss_config,
+			   struct gve_device_option_nic_timestamp **dev_op_nic_timestamp,
 			   struct gve_device_option_modify_ring **dev_op_modify_ring)
 {
 	const int num_options = be16_to_cpu(descriptor->num_device_options);
@@ -269,6 +288,7 @@ gve_process_device_options(struct gve_priv *priv,
 					dev_op_dqo_rda, dev_op_jumbo_frames,
 					dev_op_dqo_qpl, dev_op_buffer_sizes,
 					dev_op_flow_steering, dev_op_rss_config,
+					dev_op_nic_timestamp,
 					dev_op_modify_ring);
 		dev_opt = next_opt;
 	}
@@ -904,6 +924,8 @@ static void gve_enable_supported_features(struct gve_priv *priv,
 					  *dev_op_flow_steering,
 					  const struct gve_device_option_rss_config
 					  *dev_op_rss_config,
+					  const struct gve_device_option_nic_timestamp
+					  *dev_op_nic_timestamp,
 					  const struct gve_device_option_modify_ring
 					  *dev_op_modify_ring)
 {
@@ -980,10 +1002,15 @@ static void gve_enable_supported_features(struct gve_priv *priv,
 			"RSS device option enabled with key size of %u, lut size of %u.\n",
 			priv->rss_key_size, priv->rss_lut_size);
 	}
+
+	if (dev_op_nic_timestamp &&
+	    (supported_features_mask & GVE_SUP_NIC_TIMESTAMP_MASK))
+		priv->nic_timestamp_supported = true;
 }
 
 int gve_adminq_describe_device(struct gve_priv *priv)
 {
+	struct gve_device_option_nic_timestamp *dev_op_nic_timestamp = NULL;
 	struct gve_device_option_flow_steering *dev_op_flow_steering = NULL;
 	struct gve_device_option_buffer_sizes *dev_op_buffer_sizes = NULL;
 	struct gve_device_option_jumbo_frames *dev_op_jumbo_frames = NULL;
@@ -1024,6 +1051,7 @@ int gve_adminq_describe_device(struct gve_priv *priv)
 					 &dev_op_buffer_sizes,
 					 &dev_op_flow_steering,
 					 &dev_op_rss_config,
+					 &dev_op_nic_timestamp,
 					 &dev_op_modify_ring);
 	if (err)
 		goto free_device_descriptor;
@@ -1088,7 +1116,8 @@ int gve_adminq_describe_device(struct gve_priv *priv)
 	gve_enable_supported_features(priv, supported_features_mask,
 				      dev_op_jumbo_frames, dev_op_dqo_qpl,
 				      dev_op_buffer_sizes, dev_op_flow_steering,
-				      dev_op_rss_config, dev_op_modify_ring);
+				      dev_op_rss_config, dev_op_nic_timestamp,
+				      dev_op_modify_ring);
 
 free_device_descriptor:
 	dma_pool_free(priv->adminq_pool, descriptor, descriptor_bus);
diff --git a/drivers/net/ethernet/google/gve/gve_adminq.h b/drivers/net/ethernet/google/gve/gve_adminq.h
index 228217458275..42466ee640f1 100644
--- a/drivers/net/ethernet/google/gve/gve_adminq.h
+++ b/drivers/net/ethernet/google/gve/gve_adminq.h
@@ -174,6 +174,12 @@ struct gve_device_option_rss_config {
 
 static_assert(sizeof(struct gve_device_option_rss_config) == 8);
 
+struct gve_device_option_nic_timestamp {
+	__be32 supported_features_mask;
+};
+
+static_assert(sizeof(struct gve_device_option_nic_timestamp) == 4);
+
 /* Terminology:
  *
  * RDA - Raw DMA Addressing - Buffers associated with SKBs are directly DMA
@@ -192,6 +198,7 @@ enum gve_dev_opt_id {
 	GVE_DEV_OPT_ID_JUMBO_FRAMES		= 0x8,
 	GVE_DEV_OPT_ID_BUFFER_SIZES		= 0xa,
 	GVE_DEV_OPT_ID_FLOW_STEERING		= 0xb,
+	GVE_DEV_OPT_ID_NIC_TIMESTAMP		= 0xd,
 	GVE_DEV_OPT_ID_RSS_CONFIG		= 0xe,
 };
 
@@ -206,6 +213,7 @@ enum gve_dev_opt_req_feat_mask {
 	GVE_DEV_OPT_REQ_FEAT_MASK_MODIFY_RING		= 0x0,
 	GVE_DEV_OPT_REQ_FEAT_MASK_FLOW_STEERING		= 0x0,
 	GVE_DEV_OPT_REQ_FEAT_MASK_RSS_CONFIG		= 0x0,
+	GVE_DEV_OPT_REQ_FEAT_MASK_NIC_TIMESTAMP		= 0x0,
 };
 
 enum gve_sup_feature_mask {
@@ -214,6 +222,7 @@ enum gve_sup_feature_mask {
 	GVE_SUP_BUFFER_SIZES_MASK	= 1 << 4,
 	GVE_SUP_FLOW_STEERING_MASK	= 1 << 5,
 	GVE_SUP_RSS_CONFIG_MASK		= 1 << 7,
+	GVE_SUP_NIC_TIMESTAMP_MASK	= 1 << 8,
 };
 
 #define GVE_DEV_OPT_LEN_GQI_RAW_ADDRESSING 0x0
-- 
2.50.0.rc0.604.gd4ff7b7c86-goog