mlxsw: Support CQEv2 for SDQ in Spectrum-2 and newer ASICs

Currently, Tx completions are reported using Completion Queue Element
version 1 (CQEv1). These elements do not contain the Tx time stamp,
which is fine as Spectrum-1 reads Tx time stamps via a dedicated FIFO
and Spectrum-2 does not currently support PTP.

In preparation for Spectrum-2 PTP support, use CQEv2 for Spectrum-2 and
newer ASICs, as this CQE format encodes the Tx time stamp.
Signed-off-by: Danielle Ratson <danieller@nvidia.com>
Signed-off-by: Amit Cohen <amcohen@nvidia.com>
Reviewed-by: Petr Machata <petrm@nvidia.com>
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/mellanox/mlxsw/core.c

@@ -3335,6 +3335,12 @@ u32 mlxsw_core_read_frc_l(struct mlxsw_core *mlxsw_core)
 }
 EXPORT_SYMBOL(mlxsw_core_read_frc_l);
 
+bool mlxsw_core_sdq_supports_cqe_v2(struct mlxsw_core *mlxsw_core)
+{
+	return mlxsw_core->driver->sdq_supports_cqe_v2;
+}
+EXPORT_SYMBOL(mlxsw_core_sdq_supports_cqe_v2);
+
 void mlxsw_core_emad_string_tlv_enable(struct mlxsw_core *mlxsw_core)
 {
 	mlxsw_core->emad.enable_string_tlv = true;

drivers/net/ethernet/mellanox/mlxsw/core.h

@@ -427,6 +427,7 @@ struct mlxsw_driver {
 
 	u8 txhdr_len;
 	const struct mlxsw_config_profile *profile;
+	bool sdq_supports_cqe_v2;
 };
 
 int mlxsw_core_kvd_sizes_get(struct mlxsw_core *mlxsw_core,
@@ -437,6 +438,8 @@ int mlxsw_core_kvd_sizes_get(struct mlxsw_core *mlxsw_core,
 u32 mlxsw_core_read_frc_h(struct mlxsw_core *mlxsw_core);
 u32 mlxsw_core_read_frc_l(struct mlxsw_core *mlxsw_core);
 
+bool mlxsw_core_sdq_supports_cqe_v2(struct mlxsw_core *mlxsw_core);
+
 void mlxsw_core_emad_string_tlv_enable(struct mlxsw_core *mlxsw_core);
 
 bool mlxsw_core_res_valid(struct mlxsw_core *mlxsw_core,

drivers/net/ethernet/mellanox/mlxsw/pci.c

@@ -456,9 +456,9 @@ static void mlxsw_pci_cq_pre_init(struct mlxsw_pci *mlxsw_pci,
 {
 	q->u.cq.v = mlxsw_pci->max_cqe_ver;
 
-	/* For SDQ it is pointless to use CQEv2, so use CQEv1 instead */
 	if (q->u.cq.v == MLXSW_PCI_CQE_V2 &&
-	    q->num < mlxsw_pci->num_sdq_cqs)
+	    q->num < mlxsw_pci->num_sdq_cqs &&
+	    !mlxsw_core_sdq_supports_cqe_v2(mlxsw_pci->core))
 		q->u.cq.v = MLXSW_PCI_CQE_V1;
 }
 

drivers/net/ethernet/mellanox/mlxsw/spectrum.c

@@ -3831,6 +3831,7 @@ static struct mlxsw_driver mlxsw_sp1_driver = {
 	.ptp_transmitted		= mlxsw_sp_ptp_transmitted,
 	.txhdr_len			= MLXSW_TXHDR_LEN,
 	.profile			= &mlxsw_sp1_config_profile,
+	.sdq_supports_cqe_v2		= false,
 };
 
 static struct mlxsw_driver mlxsw_sp2_driver = {
@@ -3869,6 +3870,7 @@ static struct mlxsw_driver mlxsw_sp2_driver = {
 	.ptp_transmitted		= mlxsw_sp_ptp_transmitted,
 	.txhdr_len			= MLXSW_TXHDR_LEN,
 	.profile			= &mlxsw_sp2_config_profile,
+	.sdq_supports_cqe_v2		= true,
 };
 
 static struct mlxsw_driver mlxsw_sp3_driver = {
@@ -3907,6 +3909,7 @@ static struct mlxsw_driver mlxsw_sp3_driver = {
 	.ptp_transmitted		= mlxsw_sp_ptp_transmitted,
 	.txhdr_len			= MLXSW_TXHDR_LEN,
 	.profile			= &mlxsw_sp2_config_profile,
+	.sdq_supports_cqe_v2		= true,
 };
 
 static struct mlxsw_driver mlxsw_sp4_driver = {
@@ -3943,6 +3946,7 @@ static struct mlxsw_driver mlxsw_sp4_driver = {
 	.ptp_transmitted		= mlxsw_sp_ptp_transmitted,
 	.txhdr_len			= MLXSW_TXHDR_LEN,
 	.profile			= &mlxsw_sp2_config_profile,
+	.sdq_supports_cqe_v2		= true,
 };
 
 bool mlxsw_sp_port_dev_check(const struct net_device *dev)