Allow devlink_param::get() handlers to report error messages via
extack. This function is called in a few different contexts, but not
all of them will have an valid extack to use.

When devlink_param::get() is called from param_get_doit or
param_get_dumpit contexts, pass the extack through so that drivers can
report errors when retrieving param values. devlink_param::get() is
called from the context of devlink_param_notify(), pass NULL in for
the extack.

Reviewed-by: Saeed Mahameed <saeedm@nvidia.com>
Reviewed-by: Aleksandr Loktionov <aleksandr.loktionov@intel.com>
Signed-off-by: Daniel Zahka <daniel.zahka@gmail.com>
---

Notes:
    v3:
    - fix warnings about undocumented param in intel ice driver

 .../marvell/octeontx2/otx2_cpt_devlink.c      |  6 ++++--
 drivers/net/ethernet/amd/pds_core/core.h      |  3 ++-
 drivers/net/ethernet/amd/pds_core/devlink.c   |  3 ++-
 .../net/ethernet/broadcom/bnxt/bnxt_devlink.c |  6 ++++--
 .../net/ethernet/intel/i40e/i40e_devlink.c    |  3 ++-
 .../net/ethernet/intel/ice/devlink/devlink.c  | 14 ++++++++++----
 .../marvell/octeontx2/af/rvu_devlink.c        | 15 ++++++++++-----
 .../marvell/octeontx2/nic/otx2_devlink.c      |  6 ++++--
 drivers/net/ethernet/mellanox/mlx4/main.c     |  6 ++++--
 .../net/ethernet/mellanox/mlx5/core/eswitch.c |  3 ++-
 .../mellanox/mlx5/core/eswitch_offloads.c     |  3 ++-
 .../net/ethernet/mellanox/mlx5/core/fs_core.c |  3 ++-
 .../ethernet/mellanox/mlx5/core/fw_reset.c    |  3 ++-
 .../mellanox/mlx5/core/lib/nv_param.c         |  9 ++++++---
 .../mellanox/mlxsw/spectrum_acl_tcam.c        |  3 ++-
 .../ethernet/netronome/nfp/devlink_param.c    |  3 ++-
 drivers/net/ethernet/qlogic/qed/qed_devlink.c |  3 ++-
 .../net/ethernet/stmicro/stmmac/stmmac_main.c |  3 ++-
 drivers/net/ethernet/ti/am65-cpsw-nuss.c      |  3 ++-
 drivers/net/ethernet/ti/cpsw_new.c            |  6 ++++--
 drivers/net/wwan/iosm/iosm_ipc_devlink.c      |  3 ++-
 include/net/devlink.h                         |  3 ++-
 include/net/dsa.h                             |  3 ++-
 net/devlink/param.c                           | 19 +++++++++++--------
 net/dsa/devlink.c                             |  3 ++-
 25 files changed, 89 insertions(+), 46 deletions(-)

diff --git a/drivers/crypto/marvell/octeontx2/otx2_cpt_devlink.c b/drivers/crypto/marvell/octeontx2/otx2_cpt_devlink.c
index 215a1a8ba7e9..07a74f702c3a 100644
--- a/drivers/crypto/marvell/octeontx2/otx2_cpt_devlink.c
+++ b/drivers/crypto/marvell/octeontx2/otx2_cpt_devlink.c
@@ -24,7 +24,8 @@ static int otx2_cpt_dl_egrp_delete(struct devlink *dl, u32 id,
 }
 
 static int otx2_cpt_dl_uc_info(struct devlink *dl, u32 id,
-			       struct devlink_param_gset_ctx *ctx)
+			       struct devlink_param_gset_ctx *ctx,
+			       struct netlink_ext_ack *extack)
 {
 	ctx->val.vstr[0] = '\0';
 
@@ -32,7 +33,8 @@ static int otx2_cpt_dl_uc_info(struct devlink *dl, u32 id,
 }
 
 static int otx2_cpt_dl_t106_mode_get(struct devlink *dl, u32 id,
-				     struct devlink_param_gset_ctx *ctx)
+				     struct devlink_param_gset_ctx *ctx,
+				     struct netlink_ext_ack *extack)
 {
 	struct otx2_cpt_devlink *cpt_dl = devlink_priv(dl);
 	struct otx2_cptpf_dev *cptpf = cpt_dl->cptpf;
diff --git a/drivers/net/ethernet/amd/pds_core/core.h b/drivers/net/ethernet/amd/pds_core/core.h
index 0b53a1fab46d..4a6b35c84dab 100644
--- a/drivers/net/ethernet/amd/pds_core/core.h
+++ b/drivers/net/ethernet/amd/pds_core/core.h
@@ -255,7 +255,8 @@ int pdsc_dl_flash_update(struct devlink *dl,
 			 struct devlink_flash_update_params *params,
 			 struct netlink_ext_ack *extack);
 int pdsc_dl_enable_get(struct devlink *dl, u32 id,
-		       struct devlink_param_gset_ctx *ctx);
+		       struct devlink_param_gset_ctx *ctx,
+		       struct netlink_ext_ack *extack);
 int pdsc_dl_enable_set(struct devlink *dl, u32 id,
 		       struct devlink_param_gset_ctx *ctx,
 		       struct netlink_ext_ack *extack);
diff --git a/drivers/net/ethernet/amd/pds_core/devlink.c b/drivers/net/ethernet/amd/pds_core/devlink.c
index d8dc39da4161..b576be626a29 100644
--- a/drivers/net/ethernet/amd/pds_core/devlink.c
+++ b/drivers/net/ethernet/amd/pds_core/devlink.c
@@ -22,7 +22,8 @@ pdsc_viftype *pdsc_dl_find_viftype_by_id(struct pdsc *pdsc,
 }
 
 int pdsc_dl_enable_get(struct devlink *dl, u32 id,
-		       struct devlink_param_gset_ctx *ctx)
+		       struct devlink_param_gset_ctx *ctx,
+		       struct netlink_ext_ack *extack)
 {
 	struct pdsc *pdsc = devlink_priv(dl);
 	struct pdsc_viftype *vt_entry;
diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt_devlink.c b/drivers/net/ethernet/broadcom/bnxt/bnxt_devlink.c
index 67ca02d84c97..15de802bbac4 100644
--- a/drivers/net/ethernet/broadcom/bnxt/bnxt_devlink.c
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt_devlink.c
@@ -1086,7 +1086,8 @@ static int bnxt_hwrm_nvm_req(struct bnxt *bp, u32 param_id, void *msg,
 }
 
 static int bnxt_dl_nvm_param_get(struct devlink *dl, u32 id,
-				 struct devlink_param_gset_ctx *ctx)
+				 struct devlink_param_gset_ctx *ctx,
+				 struct netlink_ext_ack *extack)
 {
 	struct bnxt *bp = bnxt_get_bp_from_dl(dl);
 	struct hwrm_nvm_get_variable_input *req;
@@ -1168,7 +1169,8 @@ static int bnxt_dl_msix_validate(struct devlink *dl, u32 id,
 }
 
 static int bnxt_remote_dev_reset_get(struct devlink *dl, u32 id,
-				     struct devlink_param_gset_ctx *ctx)
+				     struct devlink_param_gset_ctx *ctx,
+				     struct netlink_ext_ack *extack)
 {
 	struct bnxt *bp = bnxt_get_bp_from_dl(dl);
 
diff --git a/drivers/net/ethernet/intel/i40e/i40e_devlink.c b/drivers/net/ethernet/intel/i40e/i40e_devlink.c
index bc205e3077c7..229179ccc131 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_devlink.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_devlink.c
@@ -24,7 +24,8 @@ static int i40e_max_mac_per_vf_set(struct devlink *devlink,
 
 static int i40e_max_mac_per_vf_get(struct devlink *devlink,
 				   u32 id,
-				   struct devlink_param_gset_ctx *ctx)
+				   struct devlink_param_gset_ctx *ctx,
+				   struct netlink_ext_ack *extack)
 {
 	struct i40e_pf *pf = devlink_priv(devlink);
 
diff --git a/drivers/net/ethernet/intel/ice/devlink/devlink.c b/drivers/net/ethernet/intel/ice/devlink/devlink.c
index 938914abbe06..d88b7f3fd1f9 100644
--- a/drivers/net/ethernet/intel/ice/devlink/devlink.c
+++ b/drivers/net/ethernet/intel/ice/devlink/devlink.c
@@ -610,11 +610,13 @@ static int ice_update_tx_topo_user_sel(struct ice_pf *pf, int layers)
  * @devlink: pointer to the devlink instance
  * @id: the parameter ID to set
  * @ctx: context to store the parameter value
+ * @extack: netlink extended ACK structure
  *
  * Return: zero on success and negative value on failure.
  */
 static int ice_devlink_tx_sched_layers_get(struct devlink *devlink, u32 id,
-					   struct devlink_param_gset_ctx *ctx)
+					   struct devlink_param_gset_ctx *ctx,
+					   struct netlink_ext_ack *extack)
 {
 	struct ice_pf *pf = devlink_priv(devlink);
 	int err;
@@ -1349,7 +1351,8 @@ static const struct devlink_ops ice_sf_devlink_ops;
 
 static int
 ice_devlink_enable_roce_get(struct devlink *devlink, u32 id,
-			    struct devlink_param_gset_ctx *ctx)
+			    struct devlink_param_gset_ctx *ctx,
+			    struct netlink_ext_ack *extack)
 {
 	struct ice_pf *pf = devlink_priv(devlink);
 	struct iidc_rdma_core_dev_info *cdev;
@@ -1415,7 +1418,8 @@ ice_devlink_enable_roce_validate(struct devlink *devlink, u32 id,
 
 static int
 ice_devlink_enable_iw_get(struct devlink *devlink, u32 id,
-			  struct devlink_param_gset_ctx *ctx)
+			  struct devlink_param_gset_ctx *ctx,
+			  struct netlink_ext_ack *extack)
 {
 	struct ice_pf *pf = devlink_priv(devlink);
 	struct iidc_rdma_core_dev_info *cdev;
@@ -1522,11 +1526,13 @@ static int ice_devlink_local_fwd_str_to_mode(const char *mode_str)
  * @devlink: Pointer to the devlink instance.
  * @id: The parameter ID to set.
  * @ctx: Context to store the parameter value.
+ * @extack: netlink extended ACK structure
  *
  * Return: Zero.
  */
 static int ice_devlink_local_fwd_get(struct devlink *devlink, u32 id,
-				     struct devlink_param_gset_ctx *ctx)
+				     struct devlink_param_gset_ctx *ctx,
+				     struct netlink_ext_ack *extack)
 {
 	struct ice_pf *pf = devlink_priv(devlink);
 	struct ice_port_info *pi;
diff --git a/drivers/net/ethernet/marvell/octeontx2/af/rvu_devlink.c b/drivers/net/ethernet/marvell/octeontx2/af/rvu_devlink.c
index 3735372539bd..0f9953eaf1b0 100644
--- a/drivers/net/ethernet/marvell/octeontx2/af/rvu_devlink.c
+++ b/drivers/net/ethernet/marvell/octeontx2/af/rvu_devlink.c
@@ -1233,7 +1233,8 @@ static int rvu_af_dl_dwrr_mtu_set(struct devlink *devlink, u32 id,
 }
 
 static int rvu_af_dl_dwrr_mtu_get(struct devlink *devlink, u32 id,
-				  struct devlink_param_gset_ctx *ctx)
+				  struct devlink_param_gset_ctx *ctx,
+				  struct netlink_ext_ack *extack)
 {
 	struct rvu_devlink *rvu_dl = devlink_priv(devlink);
 	struct rvu *rvu = rvu_dl->rvu;
@@ -1259,7 +1260,8 @@ enum rvu_af_dl_param_id {
 };
 
 static int rvu_af_npc_exact_feature_get(struct devlink *devlink, u32 id,
-					struct devlink_param_gset_ctx *ctx)
+					struct devlink_param_gset_ctx *ctx,
+					struct netlink_ext_ack *extack)
 {
 	struct rvu_devlink *rvu_dl = devlink_priv(devlink);
 	struct rvu *rvu = rvu_dl->rvu;
@@ -1314,7 +1316,8 @@ static int rvu_af_npc_exact_feature_validate(struct devlink *devlink, u32 id,
 }
 
 static int rvu_af_dl_npc_mcam_high_zone_percent_get(struct devlink *devlink, u32 id,
-						    struct devlink_param_gset_ctx *ctx)
+						    struct devlink_param_gset_ctx *ctx,
+						    struct netlink_ext_ack *extack)
 {
 	struct rvu_devlink *rvu_dl = devlink_priv(devlink);
 	struct rvu *rvu = rvu_dl->rvu;
@@ -1376,7 +1379,8 @@ static int rvu_af_dl_npc_mcam_high_zone_percent_validate(struct devlink *devlink
 }
 
 static int rvu_af_dl_npc_def_rule_cntr_get(struct devlink *devlink, u32 id,
-					   struct devlink_param_gset_ctx *ctx)
+					   struct devlink_param_gset_ctx *ctx,
+					   struct netlink_ext_ack *extack)
 {
 	struct rvu_devlink *rvu_dl = devlink_priv(devlink);
 	struct rvu *rvu = rvu_dl->rvu;
@@ -1402,7 +1406,8 @@ static int rvu_af_dl_npc_def_rule_cntr_set(struct devlink *devlink, u32 id,
 }
 
 static int rvu_af_dl_nix_maxlf_get(struct devlink *devlink, u32 id,
-				   struct devlink_param_gset_ctx *ctx)
+				   struct devlink_param_gset_ctx *ctx,
+				   struct netlink_ext_ack *extack)
 {
 	struct rvu_devlink *rvu_dl = devlink_priv(devlink);
 	struct rvu *rvu = rvu_dl->rvu;
diff --git a/drivers/net/ethernet/marvell/octeontx2/nic/otx2_devlink.c b/drivers/net/ethernet/marvell/octeontx2/nic/otx2_devlink.c
index e13ae5484c19..a72694219df4 100644
--- a/drivers/net/ethernet/marvell/octeontx2/nic/otx2_devlink.c
+++ b/drivers/net/ethernet/marvell/octeontx2/nic/otx2_devlink.c
@@ -48,7 +48,8 @@ static int otx2_dl_mcam_count_set(struct devlink *devlink, u32 id,
 }
 
 static int otx2_dl_mcam_count_get(struct devlink *devlink, u32 id,
-				  struct devlink_param_gset_ctx *ctx)
+				  struct devlink_param_gset_ctx *ctx,
+				  struct netlink_ext_ack *extack)
 {
 	struct otx2_devlink *otx2_dl = devlink_priv(devlink);
 	struct otx2_nic *pfvf = otx2_dl->pfvf;
@@ -84,7 +85,8 @@ static int otx2_dl_ucast_flt_cnt_set(struct devlink *devlink, u32 id,
 }
 
 static int otx2_dl_ucast_flt_cnt_get(struct devlink *devlink, u32 id,
-				     struct devlink_param_gset_ctx *ctx)
+				     struct devlink_param_gset_ctx *ctx,
+				     struct netlink_ext_ack *extack)
 {
 	struct otx2_devlink *otx2_dl = devlink_priv(devlink);
 	struct otx2_nic *pfvf = otx2_dl->pfvf;
diff --git a/drivers/net/ethernet/mellanox/mlx4/main.c b/drivers/net/ethernet/mellanox/mlx4/main.c
index 03d2fc7d9b09..2de226951e19 100644
--- a/drivers/net/ethernet/mellanox/mlx4/main.c
+++ b/drivers/net/ethernet/mellanox/mlx4/main.c
@@ -174,7 +174,8 @@ MODULE_PARM_DESC(port_type_array, "Array of port types: HW_DEFAULT (0) is defaul
 static atomic_t pf_loading = ATOMIC_INIT(0);
 
 static int mlx4_devlink_ierr_reset_get(struct devlink *devlink, u32 id,
-				       struct devlink_param_gset_ctx *ctx)
+				       struct devlink_param_gset_ctx *ctx,
+				       struct netlink_ext_ack *extack)
 {
 	ctx->val.vbool = !!mlx4_internal_err_reset;
 	return 0;
@@ -189,7 +190,8 @@ static int mlx4_devlink_ierr_reset_set(struct devlink *devlink, u32 id,
 }
 
 static int mlx4_devlink_crdump_snapshot_get(struct devlink *devlink, u32 id,
-					    struct devlink_param_gset_ctx *ctx)
+					    struct devlink_param_gset_ctx *ctx,
+					    struct netlink_ext_ack *extack)
 {
 	struct mlx4_priv *priv = devlink_priv(devlink);
 	struct mlx4_dev *dev = &priv->dev;
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/eswitch.c b/drivers/net/ethernet/mellanox/mlx5/core/eswitch.c
index 25af8bd7f077..90643ddae099 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/eswitch.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/eswitch.c
@@ -1969,7 +1969,8 @@ static int mlx5_devlink_esw_multiport_set(struct devlink *devlink, u32 id,
 }
 
 static int mlx5_devlink_esw_multiport_get(struct devlink *devlink, u32 id,
-					  struct devlink_param_gset_ctx *ctx)
+					  struct devlink_param_gset_ctx *ctx,
+					  struct netlink_ext_ack *extack)
 {
 	struct mlx5_core_dev *dev = devlink_priv(devlink);
 
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/eswitch_offloads.c b/drivers/net/ethernet/mellanox/mlx5/core/eswitch_offloads.c
index 8ebca0d17f65..8de6c7f6c294 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/eswitch_offloads.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/eswitch_offloads.c
@@ -2618,7 +2618,8 @@ static int esw_port_metadata_set(struct devlink *devlink, u32 id,
 }
 
 static int esw_port_metadata_get(struct devlink *devlink, u32 id,
-				 struct devlink_param_gset_ctx *ctx)
+				 struct devlink_param_gset_ctx *ctx,
+				 struct netlink_ext_ack *extack)
 {
 	struct mlx5_core_dev *dev = devlink_priv(devlink);
 
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/fs_core.c b/drivers/net/ethernet/mellanox/mlx5/core/fs_core.c
index 2b755a0035ce..0a6031a64c6f 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/fs_core.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/fs_core.c
@@ -3833,7 +3833,8 @@ static int mlx5_fs_mode_set(struct devlink *devlink, u32 id,
 }
 
 static int mlx5_fs_mode_get(struct devlink *devlink, u32 id,
-			    struct devlink_param_gset_ctx *ctx)
+			    struct devlink_param_gset_ctx *ctx,
+			    struct netlink_ext_ack *extack)
 {
 	struct mlx5_core_dev *dev = devlink_priv(devlink);
 
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/fw_reset.c b/drivers/net/ethernet/mellanox/mlx5/core/fw_reset.c
index 89e399606877..2bceb42c98cc 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/fw_reset.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/fw_reset.c
@@ -73,7 +73,8 @@ static int mlx5_fw_reset_enable_remote_dev_reset_set(struct devlink *devlink, u3
 }
 
 static int mlx5_fw_reset_enable_remote_dev_reset_get(struct devlink *devlink, u32 id,
-						     struct devlink_param_gset_ctx *ctx)
+						     struct devlink_param_gset_ctx *ctx,
+						     struct netlink_ext_ack *extack)
 {
 	struct mlx5_core_dev *dev = devlink_priv(devlink);
 	struct mlx5_fw_reset *fw_reset;
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/lib/nv_param.c b/drivers/net/ethernet/mellanox/mlx5/core/lib/nv_param.c
index f0ab5ef95fc2..3d2195338d39 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/lib/nv_param.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/lib/nv_param.c
@@ -200,7 +200,8 @@ static const char *const
 
 static int
 mlx5_nv_param_devlink_cqe_compress_get(struct devlink *devlink, u32 id,
-				       struct devlink_param_gset_ctx *ctx)
+				       struct devlink_param_gset_ctx *ctx,
+				       struct netlink_ext_ack *extack)
 {
 	struct mlx5_core_dev *dev = devlink_priv(devlink);
 	u32 mnvda[MLX5_ST_SZ_DW(mnvda_reg)] = {};
@@ -302,7 +303,8 @@ static int mlx5_nv_param_read_per_host_pf_conf(struct mlx5_core_dev *dev,
 }
 
 static int mlx5_devlink_enable_sriov_get(struct devlink *devlink, u32 id,
-					 struct devlink_param_gset_ctx *ctx)
+					 struct devlink_param_gset_ctx *ctx,
+					 struct netlink_ext_ack *extack)
 {
 	struct mlx5_core_dev *dev = devlink_priv(devlink);
 	u32 mnvda[MLX5_ST_SZ_DW(mnvda_reg)] = {};
@@ -413,7 +415,8 @@ static int mlx5_devlink_enable_sriov_set(struct devlink *devlink, u32 id,
 }
 
 static int mlx5_devlink_total_vfs_get(struct devlink *devlink, u32 id,
-				      struct devlink_param_gset_ctx *ctx)
+				      struct devlink_param_gset_ctx *ctx,
+				      struct netlink_ext_ack *extack)
 {
 	struct mlx5_core_dev *dev = devlink_priv(devlink);
 	u32 mnvda[MLX5_ST_SZ_DW(mnvda_reg)] = {};
diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum_acl_tcam.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum_acl_tcam.c
index b1d08e958bf9..69f9da9fb305 100644
--- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_acl_tcam.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_acl_tcam.c
@@ -1489,7 +1489,8 @@ mlxsw_sp_acl_tcam_vregion_rehash(struct mlxsw_sp *mlxsw_sp,
 
 static int
 mlxsw_sp_acl_tcam_region_rehash_intrvl_get(struct devlink *devlink, u32 id,
-					   struct devlink_param_gset_ctx *ctx)
+					   struct devlink_param_gset_ctx *ctx,
+					   struct netlink_ext_ack *extack)
 {
 	struct mlxsw_core *mlxsw_core = devlink_priv(devlink);
 	struct mlxsw_sp_acl_tcam *tcam;
diff --git a/drivers/net/ethernet/netronome/nfp/devlink_param.c b/drivers/net/ethernet/netronome/nfp/devlink_param.c
index 0e1a3800f371..85e3b19e6165 100644
--- a/drivers/net/ethernet/netronome/nfp/devlink_param.c
+++ b/drivers/net/ethernet/netronome/nfp/devlink_param.c
@@ -81,7 +81,8 @@ static const struct nfp_devlink_param_u8_arg nfp_devlink_u8_args[] = {
 
 static int
 nfp_devlink_param_u8_get(struct devlink *devlink, u32 id,
-			 struct devlink_param_gset_ctx *ctx)
+			 struct devlink_param_gset_ctx *ctx,
+			 struct netlink_ext_ack *extack)
 {
 	const struct nfp_devlink_param_u8_arg *arg;
 	struct nfp_pf *pf = devlink_priv(devlink);
diff --git a/drivers/net/ethernet/qlogic/qed/qed_devlink.c b/drivers/net/ethernet/qlogic/qed/qed_devlink.c
index 94c5689b5abd..0c5278c0598c 100644
--- a/drivers/net/ethernet/qlogic/qed/qed_devlink.c
+++ b/drivers/net/ethernet/qlogic/qed/qed_devlink.c
@@ -121,7 +121,8 @@ void qed_fw_reporters_destroy(struct devlink *devlink)
 }
 
 static int qed_dl_param_get(struct devlink *dl, u32 id,
-			    struct devlink_param_gset_ctx *ctx)
+			    struct devlink_param_gset_ctx *ctx,
+			    struct netlink_ext_ack *extack)
 {
 	struct qed_devlink *qed_dl = devlink_priv(dl);
 	struct qed_dev *cdev;
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index a862d5f91fce..07769547dc42 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -7493,7 +7493,8 @@ static int stmmac_dl_ts_coarse_set(struct devlink *dl, u32 id,
 }
 
 static int stmmac_dl_ts_coarse_get(struct devlink *dl, u32 id,
-				   struct devlink_param_gset_ctx *ctx)
+				   struct devlink_param_gset_ctx *ctx,
+				   struct netlink_ext_ack *extack)
 {
 	struct stmmac_devlink_priv *dl_priv = devlink_priv(dl);
 	struct stmmac_priv *priv = dl_priv->stmmac_priv;
diff --git a/drivers/net/ethernet/ti/am65-cpsw-nuss.c b/drivers/net/ethernet/ti/am65-cpsw-nuss.c
index d5f358ec9820..5924db6be3fe 100644
--- a/drivers/net/ethernet/ti/am65-cpsw-nuss.c
+++ b/drivers/net/ethernet/ti/am65-cpsw-nuss.c
@@ -3068,7 +3068,8 @@ static void am65_cpsw_init_host_port_emac(struct am65_cpsw_common *common)
 }
 
 static int am65_cpsw_dl_switch_mode_get(struct devlink *dl, u32 id,
-					struct devlink_param_gset_ctx *ctx)
+					struct devlink_param_gset_ctx *ctx,
+					struct netlink_ext_ack *extack)
 {
 	struct am65_cpsw_devlink *dl_priv = devlink_priv(dl);
 	struct am65_cpsw_common *common = dl_priv->common;
diff --git a/drivers/net/ethernet/ti/cpsw_new.c b/drivers/net/ethernet/ti/cpsw_new.c
index 8b9e2078c602..ab88d4c02cbd 100644
--- a/drivers/net/ethernet/ti/cpsw_new.c
+++ b/drivers/net/ethernet/ti/cpsw_new.c
@@ -1618,7 +1618,8 @@ static const struct devlink_ops cpsw_devlink_ops = {
 };
 
 static int cpsw_dl_switch_mode_get(struct devlink *dl, u32 id,
-				   struct devlink_param_gset_ctx *ctx)
+				   struct devlink_param_gset_ctx *ctx,
+				   struct netlink_ext_ack *extack)
 {
 	struct cpsw_devlink *dl_priv = devlink_priv(dl);
 	struct cpsw_common *cpsw = dl_priv->cpsw;
@@ -1753,7 +1754,8 @@ static int cpsw_dl_switch_mode_set(struct devlink *dl, u32 id,
 }
 
 static int cpsw_dl_ale_ctrl_get(struct devlink *dl, u32 id,
-				struct devlink_param_gset_ctx *ctx)
+				struct devlink_param_gset_ctx *ctx,
+				struct netlink_ext_ack *extack)
 {
 	struct cpsw_devlink *dl_priv = devlink_priv(dl);
 	struct cpsw_common *cpsw = dl_priv->cpsw;
diff --git a/drivers/net/wwan/iosm/iosm_ipc_devlink.c b/drivers/net/wwan/iosm/iosm_ipc_devlink.c
index 33d6342124bc..301a9d294d30 100644
--- a/drivers/net/wwan/iosm/iosm_ipc_devlink.c
+++ b/drivers/net/wwan/iosm/iosm_ipc_devlink.c
@@ -21,7 +21,8 @@ static struct iosm_coredump_file_info list[IOSM_NOF_CD_REGION] = {
 
 /* Get the param values for the specific param ID's */
 static int ipc_devlink_get_param(struct devlink *dl, u32 id,
-				 struct devlink_param_gset_ctx *ctx)
+				 struct devlink_param_gset_ctx *ctx,
+				 struct netlink_ext_ack *extack)
 {
 	struct iosm_devlink *ipc_devlink = devlink_priv(dl);
 
diff --git a/include/net/devlink.h b/include/net/devlink.h
index d01046ef0577..5f479227144d 100644
--- a/include/net/devlink.h
+++ b/include/net/devlink.h
@@ -490,7 +490,8 @@ struct devlink_param {
 	enum devlink_param_type type;
 	unsigned long supported_cmodes;
 	int (*get)(struct devlink *devlink, u32 id,
-		   struct devlink_param_gset_ctx *ctx);
+		   struct devlink_param_gset_ctx *ctx,
+		   struct netlink_ext_ack *extack);
 	int (*set)(struct devlink *devlink, u32 id,
 		   struct devlink_param_gset_ctx *ctx,
 		   struct netlink_ext_ack *extack);
diff --git a/include/net/dsa.h b/include/net/dsa.h
index 97d5f401cfcf..e40cdc12f7f3 100644
--- a/include/net/dsa.h
+++ b/include/net/dsa.h
@@ -1251,7 +1251,8 @@ struct dsa_switch_ops {
 			     dsa_devlink_param_get, dsa_devlink_param_set, NULL)
 
 int dsa_devlink_param_get(struct devlink *dl, u32 id,
-			  struct devlink_param_gset_ctx *ctx);
+			  struct devlink_param_gset_ctx *ctx,
+			  struct netlink_ext_ack *extack);
 int dsa_devlink_param_set(struct devlink *dl, u32 id,
 			  struct devlink_param_gset_ctx *ctx,
 			  struct netlink_ext_ack *extack);
diff --git a/net/devlink/param.c b/net/devlink/param.c
index 6b233b13b69a..3dbd023e4c36 100644
--- a/net/devlink/param.c
+++ b/net/devlink/param.c
@@ -174,11 +174,12 @@ devlink_param_cmode_is_supported(const struct devlink_param *param,
 
 static int devlink_param_get(struct devlink *devlink,
 			     const struct devlink_param *param,
-			     struct devlink_param_gset_ctx *ctx)
+			     struct devlink_param_gset_ctx *ctx,
+			     struct netlink_ext_ack *extack)
 {
 	if (!param->get)
 		return -EOPNOTSUPP;
-	return param->get(devlink, param->id, ctx);
+	return param->get(devlink, param->id, ctx, extack);
 }
 
 static int devlink_param_set(struct devlink *devlink,
@@ -250,7 +251,8 @@ static int devlink_nl_param_fill(struct sk_buff *msg, struct devlink *devlink,
 				 unsigned int port_index,
 				 struct devlink_param_item *param_item,
 				 enum devlink_command cmd,
-				 u32 portid, u32 seq, int flags)
+				 u32 portid, u32 seq, int flags,
+				 struct netlink_ext_ack *extack)
 {
 	union devlink_param_value param_value[DEVLINK_PARAM_CMODE_MAX + 1];
 	bool param_value_set[DEVLINK_PARAM_CMODE_MAX + 1] = {};
@@ -275,7 +277,7 @@ static int devlink_nl_param_fill(struct sk_buff *msg, struct devlink *devlink,
 				return -EOPNOTSUPP;
 		} else {
 			ctx.cmode = i;
-			err = devlink_param_get(devlink, param, &ctx);
+			err = devlink_param_get(devlink, param, &ctx, extack);
 			if (err)
 				return err;
 			param_value[i] = ctx.val;
@@ -357,7 +359,7 @@ static void devlink_param_notify(struct devlink *devlink,
 	if (!msg)
 		return;
 	err = devlink_nl_param_fill(msg, devlink, port_index, param_item, cmd,
-				    0, 0, 0);
+				    0, 0, 0, NULL);
 	if (err) {
 		nlmsg_free(msg);
 		return;
@@ -400,7 +402,8 @@ static int devlink_nl_param_get_dump_one(struct sk_buff *msg,
 		err = devlink_nl_param_fill(msg, devlink, 0, param_item,
 					    DEVLINK_CMD_PARAM_GET,
 					    NETLINK_CB(cb->skb).portid,
-					    cb->nlh->nlmsg_seq, flags);
+					    cb->nlh->nlmsg_seq, flags,
+					    cb->extack);
 		if (err == -EOPNOTSUPP) {
 			err = 0;
 		} else if (err) {
@@ -509,8 +512,8 @@ int devlink_nl_param_get_doit(struct sk_buff *skb,
 		return -ENOMEM;
 
 	err = devlink_nl_param_fill(msg, devlink, 0, param_item,
-				    DEVLINK_CMD_PARAM_GET,
-				    info->snd_portid, info->snd_seq, 0);
+				    DEVLINK_CMD_PARAM_GET, info->snd_portid,
+				    info->snd_seq, 0, info->extack);
 	if (err) {
 		nlmsg_free(msg);
 		return err;
diff --git a/net/dsa/devlink.c b/net/dsa/devlink.c
index f41f9fc2194e..ed342f345692 100644
--- a/net/dsa/devlink.c
+++ b/net/dsa/devlink.c
@@ -182,7 +182,8 @@ static const struct devlink_ops dsa_devlink_ops = {
 };
 
 int dsa_devlink_param_get(struct devlink *dl, u32 id,
-			  struct devlink_param_gset_ctx *ctx)
+			  struct devlink_param_gset_ctx *ctx,
+			  struct netlink_ext_ack *extack)
 {
 	struct dsa_switch *ds = dsa_devlink_to_ds(dl);
 
-- 
2.47.3

Lift the param type demux and value attr placement into a separate
function. This new function, devlink_nl_param_put(), can be used to
place additional types values in the value array, e.g., default,
current, next values. This commit has no functional change.

Signed-off-by: Daniel Zahka <daniel.zahka@gmail.com>
---
 net/devlink/param.c | 70 +++++++++++++++++++++++++--------------------
 1 file changed, 39 insertions(+), 31 deletions(-)

diff --git a/net/devlink/param.c b/net/devlink/param.c
index 3dbd023e4c36..3aa14ef345f0 100644
--- a/net/devlink/param.c
+++ b/net/devlink/param.c
@@ -193,58 +193,66 @@ static int devlink_param_set(struct devlink *devlink,
 }
 
 static int
-devlink_nl_param_value_fill_one(struct sk_buff *msg,
-				enum devlink_param_type type,
-				enum devlink_param_cmode cmode,
-				union devlink_param_value val)
+devlink_nl_param_value_put(struct sk_buff *msg, enum devlink_param_type type,
+			   int nla_type, union devlink_param_value val)
 {
-	struct nlattr *param_value_attr;
-
-	param_value_attr = nla_nest_start_noflag(msg,
-						 DEVLINK_ATTR_PARAM_VALUE);
-	if (!param_value_attr)
-		goto nla_put_failure;
-
-	if (nla_put_u8(msg, DEVLINK_ATTR_PARAM_VALUE_CMODE, cmode))
-		goto value_nest_cancel;
-
 	switch (type) {
 	case DEVLINK_PARAM_TYPE_U8:
-		if (nla_put_u8(msg, DEVLINK_ATTR_PARAM_VALUE_DATA, val.vu8))
-			goto value_nest_cancel;
+		if (nla_put_u8(msg, nla_type, val.vu8))
+			return -EMSGSIZE;
 		break;
 	case DEVLINK_PARAM_TYPE_U16:
-		if (nla_put_u16(msg, DEVLINK_ATTR_PARAM_VALUE_DATA, val.vu16))
-			goto value_nest_cancel;
+		if (nla_put_u16(msg, nla_type, val.vu16))
+			return -EMSGSIZE;
 		break;
 	case DEVLINK_PARAM_TYPE_U32:
-		if (nla_put_u32(msg, DEVLINK_ATTR_PARAM_VALUE_DATA, val.vu32))
-			goto value_nest_cancel;
+		if (nla_put_u32(msg, nla_type, val.vu32))
+			return -EMSGSIZE;
 		break;
 	case DEVLINK_PARAM_TYPE_U64:
-		if (devlink_nl_put_u64(msg, DEVLINK_ATTR_PARAM_VALUE_DATA,
-				       val.vu64))
-			goto value_nest_cancel;
+		if (devlink_nl_put_u64(msg, nla_type, val.vu64))
+			return -EMSGSIZE;
 		break;
 	case DEVLINK_PARAM_TYPE_STRING:
-		if (nla_put_string(msg, DEVLINK_ATTR_PARAM_VALUE_DATA,
-				   val.vstr))
-			goto value_nest_cancel;
+		if (nla_put_string(msg, nla_type, val.vstr))
+			return -EMSGSIZE;
 		break;
 	case DEVLINK_PARAM_TYPE_BOOL:
-		if (val.vbool &&
-		    nla_put_flag(msg, DEVLINK_ATTR_PARAM_VALUE_DATA))
-			goto value_nest_cancel;
+		if (val.vbool && nla_put_flag(msg, nla_type))
+			return -EMSGSIZE;
 		break;
 	}
+	return 0;
+}
+
+static int
+devlink_nl_param_value_fill_one(struct sk_buff *msg,
+				enum devlink_param_type type,
+				enum devlink_param_cmode cmode,
+				union devlink_param_value val)
+{
+	struct nlattr *param_value_attr;
+	int err = -EMSGSIZE;
+
+	param_value_attr = nla_nest_start_noflag(msg,
+						 DEVLINK_ATTR_PARAM_VALUE);
+	if (!param_value_attr)
+		return -EMSGSIZE;
+
+	if (nla_put_u8(msg, DEVLINK_ATTR_PARAM_VALUE_CMODE, cmode))
+		goto value_nest_cancel;
+
+	err = devlink_nl_param_value_put(msg, type,
+					 DEVLINK_ATTR_PARAM_VALUE_DATA, val);
+	if (err)
+		goto value_nest_cancel;
 
 	nla_nest_end(msg, param_value_attr);
 	return 0;
 
 value_nest_cancel:
 	nla_nest_cancel(msg, param_value_attr);
-nla_put_failure:
-	return -EMSGSIZE;
+	return err;
 }
 
 static int devlink_nl_param_fill(struct sk_buff *msg, struct devlink *devlink,
-- 
2.47.3

Support querying and resetting to default param values.

Introduce two new devlink netlink attrs:
DEVLINK_ATTR_PARAM_VALUE_DEFAULT and
DEVLINK_ATTR_PARAM_RESET_DEFAULT. The former is used to contain an
optional parameter value inside of the param_value nested
attribute. The latter is used in param-set requests from userspace to
indicate that the driver should reset the param to its default value.

To implement this, two new functions are added to the devlink driver
api: devlink_param::get_default() and
devlink_param::reset_default(). These callbacks allow drivers to
implement default param actions for runtime and permanent cmodes. For
driverinit params, the core latches the last value set by a driver via
devl_param_driverinit_value_set(), and uses that as the default value
for a param.

Because default parameter values are optional, it would be impossible
to discern whether or not a param of type bool has default value of
false or not provided if the default value is encoded using a netlink
flag type. For this reason, when a DEVLINK_PARAM_TYPE_BOOL has an
associated default value, the default value is encoded using a u8
type.

Signed-off-by: Daniel Zahka <daniel.zahka@gmail.com>
---
 Documentation/netlink/specs/devlink.yaml      |   9 ++
 .../networking/devlink/devlink-params.rst     |  10 ++
 include/net/devlink.h                         |  42 +++++++
 include/uapi/linux/devlink.h                  |   3 +
 net/devlink/netlink_gen.c                     |   5 +-
 net/devlink/param.c                           | 105 ++++++++++++++++--
 6 files changed, 160 insertions(+), 14 deletions(-)

diff --git a/Documentation/netlink/specs/devlink.yaml b/Documentation/netlink/specs/devlink.yaml
index 426d5aa7d955..837112da6738 100644
--- a/Documentation/netlink/specs/devlink.yaml
+++ b/Documentation/netlink/specs/devlink.yaml
@@ -859,6 +859,14 @@ attribute-sets:
         name: health-reporter-burst-period
         type: u64
         doc: Time (in msec) for recoveries before starting the grace period.
+
+      # TODO: fill in the attributes in between
+
+      -
+        name: param-reset-default
+        type: flag
+        doc: Request restoring parameter to its default value.
+        value: 183
   -
     name: dl-dev-stats
     subset-of: devlink
@@ -1793,6 +1801,7 @@ operations:
             - param-type
             # param-value-data is missing here as the type is variable
             - param-value-cmode
+            - param-reset-default
 
     -
       name: region-get
diff --git a/Documentation/networking/devlink/devlink-params.rst b/Documentation/networking/devlink/devlink-params.rst
index c0597d456641..ea17756dcda6 100644
--- a/Documentation/networking/devlink/devlink-params.rst
+++ b/Documentation/networking/devlink/devlink-params.rst
@@ -41,6 +41,16 @@ In order for ``driverinit`` parameters to take effect, the driver must
 support reloading via the ``devlink-reload`` command. This command will
 request a reload of the device driver.
 
+Default parameter values
+=========================
+
+Drivers may optionally export default values for parameters of cmode
+``runtime`` and ``permanent``. For ``driverinit`` parameters, the last
+value set by the driver will be used as the default value. Drivers can
+also support resetting params with cmode ``runtime`` and ``permanent``
+to their default values. Resetting ``driverinit`` params is supported
+by devlink core without additional driver support needed.
+
 .. _devlink_params_generic:
 
 Generic configuration parameters
diff --git a/include/net/devlink.h b/include/net/devlink.h
index 5f479227144d..cb839e0435a1 100644
--- a/include/net/devlink.h
+++ b/include/net/devlink.h
@@ -479,6 +479,10 @@ struct devlink_flash_notify {
  * @set: set parameter value, used for runtime and permanent
  *       configuration modes
  * @validate: validate input value is applicable (within value range, etc.)
+ * @get_default: get parameter default value, used for runtime and permanent
+ *               configuration modes
+ * @reset_default: reset parameter to default value, used for runtime and permanent
+ *                 configuration modes
  *
  * This struct should be used by the driver to fill the data for
  * a parameter it registers.
@@ -498,6 +502,12 @@ struct devlink_param {
 	int (*validate)(struct devlink *devlink, u32 id,
 			union devlink_param_value val,
 			struct netlink_ext_ack *extack);
+	int (*get_default)(struct devlink *devlink, u32 id,
+			   struct devlink_param_gset_ctx *ctx,
+			   struct netlink_ext_ack *extack);
+	int (*reset_default)(struct devlink *devlink, u32 id,
+			     enum devlink_param_cmode cmode,
+			     struct netlink_ext_ack *extack);
 };
 
 struct devlink_param_item {
@@ -509,6 +519,7 @@ struct devlink_param_item {
 							 * until reload.
 							 */
 	bool driverinit_value_new_valid;
+	union devlink_param_value driverinit_default;
 };
 
 enum devlink_param_generic_id {
@@ -630,6 +641,37 @@ enum devlink_param_generic_id {
 	.validate = _validate,						\
 }
 
+#define DEVLINK_PARAM_GENERIC_WITH_DEFAULTS(_id, _cmodes, _get, _set,	      \
+					    _validate, _get_default,	      \
+					    _reset_default)		      \
+{									      \
+	.id = DEVLINK_PARAM_GENERIC_ID_##_id,				      \
+	.name = DEVLINK_PARAM_GENERIC_##_id##_NAME,			      \
+	.type = DEVLINK_PARAM_GENERIC_##_id##_TYPE,			      \
+	.generic = true,						      \
+	.supported_cmodes = _cmodes,					      \
+	.get = _get,							      \
+	.set = _set,							      \
+	.validate = _validate,						      \
+	.get_default = _get_default,					      \
+	.reset_default = _reset_default,				      \
+}
+
+#define DEVLINK_PARAM_DRIVER_WITH_DEFAULTS(_id, _name, _type, _cmodes,	      \
+					   _get, _set, _validate,	      \
+					   _get_default, _reset_default)      \
+{									      \
+	.id = _id,							      \
+	.name = _name,							      \
+	.type = _type,							      \
+	.supported_cmodes = _cmodes,					      \
+	.get = _get,							      \
+	.set = _set,							      \
+	.validate = _validate,						      \
+	.get_default = _get_default,					      \
+	.reset_default = _reset_default,				      \
+}
+
 /* Identifier of board design */
 #define DEVLINK_INFO_VERSION_GENERIC_BOARD_ID	"board.id"
 /* Revision of board design */
diff --git a/include/uapi/linux/devlink.h b/include/uapi/linux/devlink.h
index 157f11d3fb72..e7d6b6d13470 100644
--- a/include/uapi/linux/devlink.h
+++ b/include/uapi/linux/devlink.h
@@ -639,6 +639,9 @@ enum devlink_attr {
 
 	DEVLINK_ATTR_HEALTH_REPORTER_BURST_PERIOD,	/* u64 */
 
+	DEVLINK_ATTR_PARAM_VALUE_DEFAULT,	/* dynamic */
+	DEVLINK_ATTR_PARAM_RESET_DEFAULT,	/* flag */
+
 	/* Add new attributes above here, update the spec in
 	 * Documentation/netlink/specs/devlink.yaml and re-generate
 	 * net/devlink/netlink_gen.c.
diff --git a/net/devlink/netlink_gen.c b/net/devlink/netlink_gen.c
index 5ad435aee29d..580985025f49 100644
--- a/net/devlink/netlink_gen.c
+++ b/net/devlink/netlink_gen.c
@@ -301,12 +301,13 @@ static const struct nla_policy devlink_param_get_dump_nl_policy[DEVLINK_ATTR_DEV
 };
 
 /* DEVLINK_CMD_PARAM_SET - do */
-static const struct nla_policy devlink_param_set_nl_policy[DEVLINK_ATTR_PARAM_VALUE_CMODE + 1] = {
+static const struct nla_policy devlink_param_set_nl_policy[DEVLINK_ATTR_PARAM_RESET_DEFAULT + 1] = {
 	[DEVLINK_ATTR_BUS_NAME] = { .type = NLA_NUL_STRING, },
 	[DEVLINK_ATTR_DEV_NAME] = { .type = NLA_NUL_STRING, },
 	[DEVLINK_ATTR_PARAM_NAME] = { .type = NLA_NUL_STRING, },
 	[DEVLINK_ATTR_PARAM_TYPE] = NLA_POLICY_VALIDATE_FN(NLA_U8, &devlink_attr_param_type_validate),
 	[DEVLINK_ATTR_PARAM_VALUE_CMODE] = NLA_POLICY_MAX(NLA_U8, 2),
+	[DEVLINK_ATTR_PARAM_RESET_DEFAULT] = { .type = NLA_FLAG, },
 };
 
 /* DEVLINK_CMD_REGION_GET - do */
@@ -919,7 +920,7 @@ const struct genl_split_ops devlink_nl_ops[74] = {
 		.doit		= devlink_nl_param_set_doit,
 		.post_doit	= devlink_nl_post_doit,
 		.policy		= devlink_param_set_nl_policy,
-		.maxattr	= DEVLINK_ATTR_PARAM_VALUE_CMODE,
+		.maxattr	= DEVLINK_ATTR_PARAM_RESET_DEFAULT,
 		.flags		= GENL_ADMIN_PERM | GENL_CMD_CAP_DO,
 	},
 	{
diff --git a/net/devlink/param.c b/net/devlink/param.c
index 3aa14ef345f0..e0ea93eded43 100644
--- a/net/devlink/param.c
+++ b/net/devlink/param.c
@@ -192,9 +192,32 @@ static int devlink_param_set(struct devlink *devlink,
 	return param->set(devlink, param->id, ctx, extack);
 }
 
+static int devlink_param_get_default(struct devlink *devlink,
+				     const struct devlink_param *param,
+				     struct devlink_param_gset_ctx *ctx,
+				     struct netlink_ext_ack *extack)
+{
+	if (!param->get_default)
+		return -EOPNOTSUPP;
+
+	return param->get_default(devlink, param->id, ctx, extack);
+}
+
+static int devlink_param_reset_default(struct devlink *devlink,
+				       const struct devlink_param *param,
+				       enum devlink_param_cmode cmode,
+				       struct netlink_ext_ack *extack)
+{
+	if (!param->reset_default)
+		return -EOPNOTSUPP;
+
+	return param->reset_default(devlink, param->id, cmode, extack);
+}
+
 static int
 devlink_nl_param_value_put(struct sk_buff *msg, enum devlink_param_type type,
-			   int nla_type, union devlink_param_value val)
+			   int nla_type, union devlink_param_value val,
+			   bool flag_as_u8)
 {
 	switch (type) {
 	case DEVLINK_PARAM_TYPE_U8:
@@ -218,8 +241,16 @@ devlink_nl_param_value_put(struct sk_buff *msg, enum devlink_param_type type,
 			return -EMSGSIZE;
 		break;
 	case DEVLINK_PARAM_TYPE_BOOL:
-		if (val.vbool && nla_put_flag(msg, nla_type))
-			return -EMSGSIZE;
+		/* default values of type bool are encoded with u8, so that
+		 * false can be distinguished from not present
+		 */
+		if (flag_as_u8) {
+			if (nla_put_u8(msg, nla_type, val.vbool))
+				return -EMSGSIZE;
+		} else {
+			if (val.vbool && nla_put_flag(msg, nla_type))
+				return -EMSGSIZE;
+		}
 		break;
 	}
 	return 0;
@@ -229,7 +260,9 @@ static int
 devlink_nl_param_value_fill_one(struct sk_buff *msg,
 				enum devlink_param_type type,
 				enum devlink_param_cmode cmode,
-				union devlink_param_value val)
+				union devlink_param_value val,
+				union devlink_param_value default_val,
+				bool has_default)
 {
 	struct nlattr *param_value_attr;
 	int err = -EMSGSIZE;
@@ -243,10 +276,19 @@ devlink_nl_param_value_fill_one(struct sk_buff *msg,
 		goto value_nest_cancel;
 
 	err = devlink_nl_param_value_put(msg, type,
-					 DEVLINK_ATTR_PARAM_VALUE_DATA, val);
+					 DEVLINK_ATTR_PARAM_VALUE_DATA,
+					 val, false);
 	if (err)
 		goto value_nest_cancel;
 
+	if (has_default) {
+		err = devlink_nl_param_value_put(msg, type,
+						 DEVLINK_ATTR_PARAM_VALUE_DEFAULT,
+						 default_val, true);
+		if (err)
+			goto value_nest_cancel;
+	}
+
 	nla_nest_end(msg, param_value_attr);
 	return 0;
 
@@ -262,7 +304,9 @@ static int devlink_nl_param_fill(struct sk_buff *msg, struct devlink *devlink,
 				 u32 portid, u32 seq, int flags,
 				 struct netlink_ext_ack *extack)
 {
+	union devlink_param_value default_value[DEVLINK_PARAM_CMODE_MAX + 1];
 	union devlink_param_value param_value[DEVLINK_PARAM_CMODE_MAX + 1];
+	bool default_value_set[DEVLINK_PARAM_CMODE_MAX + 1] = {};
 	bool param_value_set[DEVLINK_PARAM_CMODE_MAX + 1] = {};
 	const struct devlink_param *param = param_item->param;
 	struct devlink_param_gset_ctx ctx;
@@ -283,12 +327,26 @@ static int devlink_nl_param_fill(struct sk_buff *msg, struct devlink *devlink,
 				param_value[i] = param_item->driverinit_value;
 			else
 				return -EOPNOTSUPP;
+
+			if (param_item->driverinit_value_valid) {
+				default_value[i] = param_item->driverinit_default;
+				default_value_set[i] = true;
+			}
 		} else {
 			ctx.cmode = i;
 			err = devlink_param_get(devlink, param, &ctx, extack);
 			if (err)
 				return err;
 			param_value[i] = ctx.val;
+
+			err = devlink_param_get_default(devlink, param, &ctx,
+							extack);
+			if (!err) {
+				default_value[i] = ctx.val;
+				default_value_set[i] = true;
+			} else if (err != -EOPNOTSUPP) {
+				return err;
+			}
 		}
 		param_value_set[i] = true;
 	}
@@ -325,7 +383,9 @@ static int devlink_nl_param_fill(struct sk_buff *msg, struct devlink *devlink,
 		if (!param_value_set[i])
 			continue;
 		err = devlink_nl_param_value_fill_one(msg, param->type,
-						      i, param_value[i]);
+						      i, param_value[i],
+						      default_value[i],
+						      default_value_set[i]);
 		if (err)
 			goto values_list_nest_cancel;
 	}
@@ -542,6 +602,7 @@ static int __devlink_nl_cmd_param_set_doit(struct devlink *devlink,
 	struct devlink_param_item *param_item;
 	const struct devlink_param *param;
 	union devlink_param_value value;
+	bool reset_default;
 	int err = 0;
 
 	param_item = devlink_param_get_from_info(params, info);
@@ -553,13 +614,18 @@ static int __devlink_nl_cmd_param_set_doit(struct devlink *devlink,
 		return err;
 	if (param_type != param->type)
 		return -EINVAL;
-	err = devlink_param_value_get_from_info(param, info, &value);
-	if (err)
-		return err;
-	if (param->validate) {
-		err = param->validate(devlink, param->id, value, info->extack);
+
+	reset_default = info->attrs[DEVLINK_ATTR_PARAM_RESET_DEFAULT];
+	if (!reset_default) {
+		err = devlink_param_value_get_from_info(param, info, &value);
 		if (err)
 			return err;
+		if (param->validate) {
+			err = param->validate(devlink, param->id, value,
+					      info->extack);
+			if (err)
+				return err;
+		}
 	}
 
 	if (GENL_REQ_ATTR_CHECK(info, DEVLINK_ATTR_PARAM_VALUE_CMODE))
@@ -569,6 +635,15 @@ static int __devlink_nl_cmd_param_set_doit(struct devlink *devlink,
 		return -EOPNOTSUPP;
 
 	if (cmode == DEVLINK_PARAM_CMODE_DRIVERINIT) {
+		if (reset_default) {
+			if (!param_item->driverinit_value_valid) {
+				NL_SET_ERR_MSG(info->extack,
+					       "Default value not available");
+				return -EOPNOTSUPP;
+			}
+			value = param_item->driverinit_default;
+		}
+
 		param_item->driverinit_value_new = value;
 		param_item->driverinit_value_new_valid = true;
 	} else {
@@ -576,7 +651,12 @@ static int __devlink_nl_cmd_param_set_doit(struct devlink *devlink,
 			return -EOPNOTSUPP;
 		ctx.val = value;
 		ctx.cmode = cmode;
-		err = devlink_param_set(devlink, param, &ctx, info->extack);
+		if (reset_default)
+			err = devlink_param_reset_default(devlink, param, cmode,
+							  info->extack);
+		else
+			err = devlink_param_set(devlink, param, &ctx,
+						info->extack);
 		if (err)
 			return err;
 	}
@@ -824,6 +904,7 @@ void devl_param_driverinit_value_set(struct devlink *devlink, u32 param_id,
 
 	param_item->driverinit_value = init_val;
 	param_item->driverinit_value_valid = true;
+	param_item->driverinit_default = init_val;
 
 	devlink_param_notify(devlink, 0, param_item, DEVLINK_CMD_PARAM_NEW);
 }
-- 
2.47.3

swp_l4_csum_mode controls how L4 transmit checksums are computed when
using Software Parser (SWP) hints for header locations.

Supported values:
  1. default: device will choose between full_csum or l4_only. Driver
     will discover the device's choice during initialization.
  2. full_csum: calculate L4 checksum with the pseudo-header.
  3. l4_only: calculate L4 checksum without the pseudo-header. Only
     available when swp_l4_csum_mode_l4_only is set in
     mlx5_ifc_nv_sw_offload_cap_bits.

Note that 'default' might be returned from the device and passed to
userspace, and it might also be set during a
devlink_param::reset_default() call, but attempts to set a value of
default directly with param-set will be rejected.

The l4_only setting is a dependency for PSP initialization in
mlx5e_psp_init().

Reviewed-by: Aleksandr Loktionov <aleksandr.loktionov@intel.com>
Signed-off-by: Daniel Zahka <daniel.zahka@gmail.com>
---

Notes:
    v4:
    - rename device_default to default
    - implement get_default and reset_default handlers
    - don't allow user to request "default" in set cmd
    v2:
    - use extack in mlx5_nv_param_devlink_swp_l4_csum_mode_get()
    - fix indentation issue in mlx5.rst entry

 Documentation/networking/devlink/mlx5.rst     |  14 ++
 .../net/ethernet/mellanox/mlx5/core/devlink.h |   3 +-
 .../mellanox/mlx5/core/lib/nv_param.c         | 229 ++++++++++++++++++
 3 files changed, 245 insertions(+), 1 deletion(-)

diff --git a/Documentation/networking/devlink/mlx5.rst b/Documentation/networking/devlink/mlx5.rst
index 0e5f9c76e514..4bba4d780a4a 100644
--- a/Documentation/networking/devlink/mlx5.rst
+++ b/Documentation/networking/devlink/mlx5.rst
@@ -218,6 +218,20 @@ parameters.
        * ``balanced`` : Merges fewer CQEs, resulting in a moderate compression ratio but maintaining a balance between bandwidth savings and performance
        * ``aggressive`` : Merges more CQEs into a single entry, achieving a higher compression rate and maximizing performance, particularly under high traffic loads
 
+   * - ``swp_l4_csum_mode``
+     - string
+     - permanent
+     - Configure how the L4 checksum is calculated by the device when using
+       Software Parser (SWP) hints for header locations.
+
+       * ``default`` : Use the device's default checksum calculation
+         mode. The driver will discover during init whether or
+         full_csum or l4_only is in use. Setting this value explicitly
+         from userspace is not allowed, but some firmware versions may
+         return this value on param read.
+       * ``full_csum`` : Calculate full checksum including the pseudo-header
+       * ``l4_only`` : Calculate L4-only checksum, excluding the pseudo-header
+
 The ``mlx5`` driver supports reloading via ``DEVLINK_CMD_RELOAD``
 
 Info versions
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/devlink.h b/drivers/net/ethernet/mellanox/mlx5/core/devlink.h
index c9555119a661..43b9bf8829cf 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/devlink.h
+++ b/drivers/net/ethernet/mellanox/mlx5/core/devlink.h
@@ -26,7 +26,8 @@ enum mlx5_devlink_param_id {
 	MLX5_DEVLINK_PARAM_ID_PCIE_CONG_IN_HIGH,
 	MLX5_DEVLINK_PARAM_ID_PCIE_CONG_OUT_LOW,
 	MLX5_DEVLINK_PARAM_ID_PCIE_CONG_OUT_HIGH,
-	MLX5_DEVLINK_PARAM_ID_CQE_COMPRESSION_TYPE
+	MLX5_DEVLINK_PARAM_ID_CQE_COMPRESSION_TYPE,
+	MLX5_DEVLINK_PARAM_ID_SWP_L4_CSUM_MODE,
 };
 
 struct mlx5_trap_ctx {
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/lib/nv_param.c b/drivers/net/ethernet/mellanox/mlx5/core/lib/nv_param.c
index 3d2195338d39..2dfc3fc367c0 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/lib/nv_param.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/lib/nv_param.c
@@ -8,6 +8,8 @@ enum {
 	MLX5_CLASS_0_CTRL_ID_NV_GLOBAL_PCI_CONF               = 0x80,
 	MLX5_CLASS_0_CTRL_ID_NV_GLOBAL_PCI_CAP                = 0x81,
 	MLX5_CLASS_0_CTRL_ID_NV_SW_OFFLOAD_CONFIG             = 0x10a,
+	MLX5_CLASS_0_CTRL_ID_NV_SW_OFFLOAD_CAP                = 0x10b,
+	MLX5_CLASS_0_CTRL_ID_NV_SW_ACCELERATE_CONF            = 0x11d,
 
 	MLX5_CLASS_3_CTRL_ID_NV_PF_PCI_CONF                   = 0x80,
 };
@@ -32,6 +34,12 @@ union mlx5_ifc_config_item_type_auto_bits {
 	u8 reserved_at_0[0x20];
 };
 
+enum {
+	MLX5_ACCESS_MODE_NEXT = 0,
+	MLX5_ACCESS_MODE_CURRENT,
+	MLX5_ACCESS_MODE_DEFAULT,
+};
+
 struct mlx5_ifc_config_item_bits {
 	u8         valid[0x2];
 	u8         priority[0x2];
@@ -123,6 +131,17 @@ struct mlx5_ifc_nv_sw_offload_conf_bits {
 	u8         lro_log_timeout0[0x4];
 };
 
+struct mlx5_ifc_nv_sw_offload_cap_bits {
+	u8         reserved_at_0[0x19];
+	u8         swp_l4_csum_mode_l4_only[0x1];
+	u8         reserved_at_1a[0x6];
+};
+
+struct mlx5_ifc_nv_sw_accelerate_conf_bits {
+	u8         swp_l4_csum_mode[0x2];
+	u8         reserved_at_2[0x3e];
+};
+
 #define MNVDA_HDR_SZ \
 	(MLX5_ST_SZ_BYTES(mnvda_reg) - \
 	 MLX5_BYTE_OFF(mnvda_reg, configuration_item_data))
@@ -195,6 +214,32 @@ mlx5_nv_param_read_sw_offload_conf(struct mlx5_core_dev *dev, void *mnvda,
 	return mlx5_nv_param_read(dev, mnvda, len);
 }
 
+static int
+mlx5_nv_param_read_sw_offload_cap(struct mlx5_core_dev *dev, void *mnvda,
+				  size_t len)
+{
+	MLX5_SET_CFG_ITEM_TYPE(global, mnvda, type_class, 0);
+	MLX5_SET_CFG_ITEM_TYPE(global, mnvda, parameter_index,
+			       MLX5_CLASS_0_CTRL_ID_NV_SW_OFFLOAD_CAP);
+	MLX5_SET_CFG_HDR_LEN(mnvda, nv_sw_offload_cap);
+
+	return mlx5_nv_param_read(dev, mnvda, len);
+}
+
+static int
+mlx5_nv_param_read_sw_accelerate_conf(struct mlx5_core_dev *dev, void *mnvda,
+				      size_t len, int access_mode)
+{
+	MLX5_SET_CFG_ITEM_TYPE(global, mnvda, type_class, 0);
+	MLX5_SET_CFG_ITEM_TYPE(global, mnvda, parameter_index,
+			       MLX5_CLASS_0_CTRL_ID_NV_SW_ACCELERATE_CONF);
+	MLX5_SET_CFG_HDR_LEN(mnvda, nv_sw_accelerate_conf);
+	MLX5_SET(mnvda_reg, mnvda, configuration_item_header.access_mode,
+		 access_mode);
+
+	return mlx5_nv_param_read(dev, mnvda, len);
+}
+
 static const char *const
 	cqe_compress_str[] = { "balanced", "aggressive" };
 
@@ -269,6 +314,182 @@ mlx5_nv_param_devlink_cqe_compress_set(struct devlink *devlink, u32 id,
 	return mlx5_nv_param_write(dev, mnvda, sizeof(mnvda));
 }
 
+enum swp_l4_csum_mode {
+	SWP_L4_CSUM_MODE_DEFAULT = 0,
+	SWP_L4_CSUM_MODE_FULL_CSUM = 1,
+	SWP_L4_CSUM_MODE_L4_ONLY = 2,
+};
+
+static const char *const
+	swp_l4_csum_mode_str[] = { "default", "full_csum", "l4_only" };
+
+static int
+mlx5_swp_l4_csum_mode_get(struct devlink *devlink, u32 id,
+			  int access_mode, u8 *value,
+			  struct netlink_ext_ack *extack)
+{
+	struct mlx5_core_dev *dev = devlink_priv(devlink);
+	u32 mnvda[MLX5_ST_SZ_DW(mnvda_reg)] = {};
+	void *data;
+	int err;
+
+	err = mlx5_nv_param_read_sw_accelerate_conf(dev, mnvda, sizeof(mnvda),
+						    access_mode);
+	if (err) {
+		NL_SET_ERR_MSG_MOD(extack,
+				   "Failed to read sw_accelerate_conf mnvda reg");
+		return err;
+	}
+
+	data = MLX5_ADDR_OF(mnvda_reg, mnvda, configuration_item_data);
+	*value = MLX5_GET(nv_sw_accelerate_conf, data, swp_l4_csum_mode);
+
+	if (*value >= ARRAY_SIZE(swp_l4_csum_mode_str)) {
+		NL_SET_ERR_MSG_FMT_MOD(extack,
+				       "Invalid swp_l4_csum_mode value %u read from device",
+				       *value);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int
+mlx5_devlink_swp_l4_csum_mode_get(struct devlink *devlink, u32 id,
+				  struct devlink_param_gset_ctx *ctx,
+				  struct netlink_ext_ack *extack)
+{
+	u8 value;
+	int err;
+
+	err = mlx5_swp_l4_csum_mode_get(devlink, id, MLX5_ACCESS_MODE_NEXT,
+					&value, extack);
+	if (err)
+		return err;
+
+	strscpy(ctx->val.vstr, swp_l4_csum_mode_str[value],
+		sizeof(ctx->val.vstr));
+	return 0;
+}
+
+static int
+mlx5_devlink_swp_l4_csum_mode_validate(struct devlink *devlink, u32 id,
+				       union devlink_param_value val,
+				       struct netlink_ext_ack *extack)
+{
+	struct mlx5_core_dev *dev = devlink_priv(devlink);
+	u32 cap[MLX5_ST_SZ_DW(mnvda_reg)] = {};
+	void *data;
+	int err, i;
+
+	for (i = 0; i < ARRAY_SIZE(swp_l4_csum_mode_str); i++) {
+		if (!strcmp(val.vstr, swp_l4_csum_mode_str[i]))
+			break;
+	}
+
+	if (i >= ARRAY_SIZE(swp_l4_csum_mode_str) ||
+	    i == SWP_L4_CSUM_MODE_DEFAULT) {
+		NL_SET_ERR_MSG_MOD(extack,
+				   "Invalid value, supported values are full_csum/l4_only");
+		return -EINVAL;
+	}
+
+	if (i == SWP_L4_CSUM_MODE_L4_ONLY) {
+		err = mlx5_nv_param_read_sw_offload_cap(dev, cap, sizeof(cap));
+		if (err) {
+			NL_SET_ERR_MSG_MOD(extack,
+					   "Failed to read sw_offload_cap");
+			return err;
+		}
+
+		data = MLX5_ADDR_OF(mnvda_reg, cap, configuration_item_data);
+		if (!MLX5_GET(nv_sw_offload_cap, data, swp_l4_csum_mode_l4_only)) {
+			NL_SET_ERR_MSG_MOD(extack,
+					   "l4_only mode is not supported on this device");
+			return -EOPNOTSUPP;
+		}
+	}
+
+	return 0;
+}
+
+static int
+mlx5_swp_l4_csum_mode_set(struct devlink *devlink, u32 id, u8 value,
+			  struct netlink_ext_ack *extack)
+{
+	struct mlx5_core_dev *dev = devlink_priv(devlink);
+	u32 mnvda[MLX5_ST_SZ_DW(mnvda_reg)] = {};
+	void *data;
+	int err;
+
+	err = mlx5_nv_param_read_sw_accelerate_conf(dev, mnvda, sizeof(mnvda),
+						    MLX5_ACCESS_MODE_NEXT);
+	if (err) {
+		NL_SET_ERR_MSG_MOD(extack,
+				   "Failed to read sw_accelerate_conf mnvda reg");
+		return err;
+	}
+
+	data = MLX5_ADDR_OF(mnvda_reg, mnvda, configuration_item_data);
+	MLX5_SET(nv_sw_accelerate_conf, data, swp_l4_csum_mode, value);
+
+	err = mlx5_nv_param_write(dev, mnvda, sizeof(mnvda));
+	if (err)
+		NL_SET_ERR_MSG_MOD(extack,
+				   "Failed to write sw_accelerate_conf mnvda reg");
+
+	return err;
+}
+
+static int
+mlx5_devlink_swp_l4_csum_mode_set(struct devlink *devlink, u32 id,
+				  struct devlink_param_gset_ctx *ctx,
+				  struct netlink_ext_ack *extack)
+{
+	u8 value;
+
+	if (!strcmp(ctx->val.vstr, "full_csum"))
+		value = SWP_L4_CSUM_MODE_FULL_CSUM;
+	else
+		value = SWP_L4_CSUM_MODE_L4_ONLY;
+
+	return mlx5_swp_l4_csum_mode_set(devlink, id, value, extack);
+}
+
+static int
+mlx5_devlink_swp_l4_csum_mode_get_default(struct devlink *devlink, u32 id,
+					  struct devlink_param_gset_ctx *ctx,
+					  struct netlink_ext_ack *extack)
+{
+	u8 value;
+	int err;
+
+	err = mlx5_swp_l4_csum_mode_get(devlink, id, MLX5_ACCESS_MODE_DEFAULT,
+					&value, extack);
+	if (err)
+		return err;
+
+	strscpy(ctx->val.vstr, swp_l4_csum_mode_str[value],
+		sizeof(ctx->val.vstr));
+	return 0;
+}
+
+static int
+mlx5_devlink_swp_l4_csum_mode_set_default(struct devlink *devlink, u32 id,
+					  enum devlink_param_cmode cmode,
+					  struct netlink_ext_ack *extack)
+{
+	u8 value;
+	int err;
+
+	err = mlx5_swp_l4_csum_mode_get(devlink, id, MLX5_ACCESS_MODE_DEFAULT,
+					&value, extack);
+	if (err)
+		return err;
+
+	return mlx5_swp_l4_csum_mode_set(devlink, id, value, extack);
+}
+
 static int mlx5_nv_param_read_global_pci_conf(struct mlx5_core_dev *dev,
 					      void *mnvda, size_t len)
 {
@@ -548,6 +769,14 @@ static const struct devlink_param mlx5_nv_param_devlink_params[] = {
 			     mlx5_nv_param_devlink_cqe_compress_get,
 			     mlx5_nv_param_devlink_cqe_compress_set,
 			     mlx5_nv_param_devlink_cqe_compress_validate),
+	DEVLINK_PARAM_DRIVER_WITH_DEFAULTS(MLX5_DEVLINK_PARAM_ID_SWP_L4_CSUM_MODE,
+					   "swp_l4_csum_mode", DEVLINK_PARAM_TYPE_STRING,
+					   BIT(DEVLINK_PARAM_CMODE_PERMANENT),
+					   mlx5_devlink_swp_l4_csum_mode_get,
+					   mlx5_devlink_swp_l4_csum_mode_set,
+					   mlx5_devlink_swp_l4_csum_mode_validate,
+					   mlx5_devlink_swp_l4_csum_mode_get_default,
+					   mlx5_devlink_swp_l4_csum_mode_set_default),
 };
 
 int mlx5_nv_param_register_dl_params(struct devlink *devlink)
-- 
2.47.3

Create a new devlink param, test2, that supports default param actions
via the devlink_param::get_default() and
devlink_param::reset_default() functions.

Reviewed-by: Aleksandr Loktionov <aleksandr.loktionov@intel.com>
Signed-off-by: Daniel Zahka <daniel.zahka@gmail.com>
---

Notes:
    v5:
     - don't use magic value in get_default() reset_default()

 drivers/net/netdevsim/dev.c       | 56 +++++++++++++++++++++++++++++++
 drivers/net/netdevsim/netdevsim.h |  1 +
 2 files changed, 57 insertions(+)

diff --git a/drivers/net/netdevsim/dev.c b/drivers/net/netdevsim/dev.c
index 95f66c1f59db..2683a989873e 100644
--- a/drivers/net/netdevsim/dev.c
+++ b/drivers/net/netdevsim/dev.c
@@ -320,6 +320,8 @@ static int nsim_dev_debugfs_init(struct nsim_dev *nsim_dev)
 			   &nsim_dev->max_macs);
 	debugfs_create_bool("test1", 0600, nsim_dev->ddir,
 			    &nsim_dev->test1);
+	debugfs_create_u32("test2", 0600, nsim_dev->ddir,
+			   &nsim_dev->test2);
 	nsim_dev->take_snapshot = debugfs_create_file("take_snapshot",
 						      0200,
 						      nsim_dev->ddir,
@@ -521,8 +523,53 @@ static int nsim_dev_resources_register(struct devlink *devlink)
 enum nsim_devlink_param_id {
 	NSIM_DEVLINK_PARAM_ID_BASE = DEVLINK_PARAM_GENERIC_ID_MAX,
 	NSIM_DEVLINK_PARAM_ID_TEST1,
+	NSIM_DEVLINK_PARAM_ID_TEST2,
 };
 
+static int
+nsim_devlink_param_test2_get(struct devlink *devlink, u32 id,
+			     struct devlink_param_gset_ctx *ctx,
+			     struct netlink_ext_ack *extack)
+{
+	struct nsim_dev *nsim_dev = devlink_priv(devlink);
+
+	ctx->val.vu32 = nsim_dev->test2;
+	return 0;
+}
+
+static int
+nsim_devlink_param_test2_set(struct devlink *devlink, u32 id,
+			     struct devlink_param_gset_ctx *ctx,
+			     struct netlink_ext_ack *extack)
+{
+	struct nsim_dev *nsim_dev = devlink_priv(devlink);
+
+	nsim_dev->test2 = ctx->val.vu32;
+	return 0;
+}
+
+#define NSIM_DEV_TEST2_DEFAULT 1234
+
+static int
+nsim_devlink_param_test2_get_default(struct devlink *devlink, u32 id,
+				     struct devlink_param_gset_ctx *ctx,
+				     struct netlink_ext_ack *extack)
+{
+	ctx->val.vu32 = NSIM_DEV_TEST2_DEFAULT;
+	return 0;
+}
+
+static int
+nsim_devlink_param_test2_reset_default(struct devlink *devlink, u32 id,
+				       enum devlink_param_cmode cmode,
+				       struct netlink_ext_ack *extack)
+{
+	struct nsim_dev *nsim_dev = devlink_priv(devlink);
+
+	nsim_dev->test2 = NSIM_DEV_TEST2_DEFAULT;
+	return 0;
+}
+
 static const struct devlink_param nsim_devlink_params[] = {
 	DEVLINK_PARAM_GENERIC(MAX_MACS,
 			      BIT(DEVLINK_PARAM_CMODE_DRIVERINIT),
@@ -531,6 +578,14 @@ static const struct devlink_param nsim_devlink_params[] = {
 			     "test1", DEVLINK_PARAM_TYPE_BOOL,
 			     BIT(DEVLINK_PARAM_CMODE_DRIVERINIT),
 			     NULL, NULL, NULL),
+	DEVLINK_PARAM_DRIVER_WITH_DEFAULTS(NSIM_DEVLINK_PARAM_ID_TEST2,
+					   "test2", DEVLINK_PARAM_TYPE_U32,
+					   BIT(DEVLINK_PARAM_CMODE_RUNTIME),
+					   nsim_devlink_param_test2_get,
+					   nsim_devlink_param_test2_set,
+					   NULL,
+					   nsim_devlink_param_test2_get_default,
+					   nsim_devlink_param_test2_reset_default),
 };
 
 static void nsim_devlink_set_params_init_values(struct nsim_dev *nsim_dev,
@@ -1590,6 +1645,7 @@ int nsim_drv_probe(struct nsim_bus_dev *nsim_bus_dev)
 	nsim_dev->fw_update_flash_chunk_time_ms = NSIM_DEV_FLASH_CHUNK_TIME_MS_DEFAULT;
 	nsim_dev->max_macs = NSIM_DEV_MAX_MACS_DEFAULT;
 	nsim_dev->test1 = NSIM_DEV_TEST1_DEFAULT;
+	nsim_dev->test2 = NSIM_DEV_TEST2_DEFAULT;
 	spin_lock_init(&nsim_dev->fa_cookie_lock);
 
 	dev_set_drvdata(&nsim_bus_dev->dev, nsim_dev);
diff --git a/drivers/net/netdevsim/netdevsim.h b/drivers/net/netdevsim/netdevsim.h
index af6fcfcda8ba..d1a941e2b18f 100644
--- a/drivers/net/netdevsim/netdevsim.h
+++ b/drivers/net/netdevsim/netdevsim.h
@@ -331,6 +331,7 @@ struct nsim_dev {
 	u32 fw_update_flash_chunk_time_ms;
 	u32 max_macs;
 	bool test1;
+	u32 test2;
 	bool dont_allow_reload;
 	bool fail_reload;
 	struct devlink_region *dummy_region;
-- 
2.47.3

Test querying default values and resetting to default values for
netdevsim devlink params.

This should cover the basic paths of interest: driverinit and
non-driverinit cmodes, as well as bool and non-bool value
type. Default param values of type bool are encoded with u8 netlink
type as opposed to flag type, so that userspace can distinguish
"not-present" from false.

Signed-off-by: Daniel Zahka <daniel.zahka@gmail.com>
---
 .../drivers/net/netdevsim/devlink.sh          | 116 +++++++++++++++++-
 1 file changed, 110 insertions(+), 6 deletions(-)

diff --git a/tools/testing/selftests/drivers/net/netdevsim/devlink.sh b/tools/testing/selftests/drivers/net/netdevsim/devlink.sh
index 030762b203d7..1b529ccaf050 100755
--- a/tools/testing/selftests/drivers/net/netdevsim/devlink.sh
+++ b/tools/testing/selftests/drivers/net/netdevsim/devlink.sh
@@ -3,7 +3,8 @@
 
 lib_dir=$(dirname $0)/../../../net/forwarding
 
-ALL_TESTS="fw_flash_test params_test regions_test reload_test \
+ALL_TESTS="fw_flash_test params_test  \
+	   params_default_test regions_test reload_test \
 	   netns_reload_test resource_test dev_info_test \
 	   empty_reporter_test dummy_reporter_test rate_test"
 NUM_NETIFS=0
@@ -78,17 +79,28 @@ fw_flash_test()
 param_get()
 {
 	local name=$1
+	local attr=${2:-value}
+	local cmode=${3:-driverinit}
 
 	cmd_jq "devlink dev param show $DL_HANDLE name $name -j" \
-	       '.[][][].values[] | select(.cmode == "driverinit").value'
+	       '.[][][].values[] | select(.cmode == "'"$cmode"'").'"$attr"
 }
 
 param_set()
 {
 	local name=$1
 	local value=$2
+	local cmode=${3:-driverinit}
 
-	devlink dev param set $DL_HANDLE name $name cmode driverinit value $value
+	devlink dev param set $DL_HANDLE name $name cmode $cmode value $value
+}
+
+param_set_default()
+{
+	local name=$1
+	local cmode=${2:-driverinit}
+
+	devlink dev param set $DL_HANDLE name $name default cmode $cmode
 }
 
 check_value()
@@ -97,12 +109,18 @@ check_value()
 	local phase_name=$2
 	local expected_param_value=$3
 	local expected_debugfs_value=$4
+	local cmode=${5:-driverinit}
 	local value
+	local attr="value"
 
-	value=$(param_get $name)
-	check_err $? "Failed to get $name param value"
+	if [[ "$phase_name" == *"default"* ]]; then
+		attr="default"
+	fi
+
+	value=$(param_get $name $attr $cmode)
+	check_err $? "Failed to get $name param $attr"
 	[ "$value" == "$expected_param_value" ]
-	check_err $? "Unexpected $phase_name $name param value"
+	check_err $? "Unexpected $phase_name $name param $attr"
 	value=$(<$DEBUGFS_DIR/$name)
 	check_err $? "Failed to get $name debugfs value"
 	[ "$value" == "$expected_debugfs_value" ]
@@ -135,6 +153,92 @@ params_test()
 	log_test "params test"
 }
 
+value_to_debugfs()
+{
+	local value=$1
+
+	case "$value" in
+		true)
+			echo "Y"
+			;;
+		false)
+			echo "N"
+			;;
+		*)
+			echo "$value"
+			;;
+	esac
+}
+
+test_default()
+{
+	local param_name=$1
+	local new_value=$2
+	local expected_default=$3
+	local cmode=${4:-driverinit}
+	local default_debugfs
+	local new_debugfs
+	local expected_debugfs
+
+	default_debugfs=$(value_to_debugfs $expected_default)
+	new_debugfs=$(value_to_debugfs $new_value)
+
+	expected_debugfs=$default_debugfs
+	check_value $param_name initial-default $expected_default $expected_debugfs $cmode
+
+	param_set $param_name $new_value $cmode
+	check_err $? "Failed to set $param_name to $new_value"
+
+	expected_debugfs=$([ "$cmode" == "runtime" ] && echo "$new_debugfs" || echo "$default_debugfs")
+	check_value $param_name post-set $new_value $expected_debugfs $cmode
+
+	devlink dev reload $DL_HANDLE
+	check_err $? "Failed to reload device"
+
+	expected_debugfs=$new_debugfs
+	check_value $param_name post-reload-new-value $new_value $expected_debugfs $cmode
+
+	param_set_default $param_name $cmode
+	check_err $? "Failed to set $param_name to default"
+
+	expected_debugfs=$([ "$cmode" == "runtime" ] && echo "$default_debugfs" || echo "$new_debugfs")
+	check_value $param_name post-set-default $expected_default $expected_debugfs $cmode
+
+	devlink dev reload $DL_HANDLE
+	check_err $? "Failed to reload device"
+
+	expected_debugfs=$default_debugfs
+	check_value $param_name post-reload-default $expected_default $expected_debugfs $cmode
+}
+
+params_default_test()
+{
+	RET=0
+
+	if ! devlink dev param help 2>&1 | grep -q "value VALUE | default"; then
+		echo "SKIP: devlink cli missing default feature"
+		return
+	fi
+
+	# Remove side effects of previous tests. Use plain param_set, because
+	# param_set_default is a feature under test here.
+	param_set max_macs 32 driverinit
+	check_err $? "Failed to reset max_macs to default value"
+	param_set test1 true driverinit
+	check_err $? "Failed to reset test1 to default value"
+	param_set test2 1234 runtime
+	check_err $? "Failed to reset test2 to default value"
+
+	devlink dev reload $DL_HANDLE
+	check_err $? "Failed to reload device for clean state"
+
+	test_default max_macs 16 32 driverinit
+	test_default test1 false true driverinit
+	test_default test2 100 1234 runtime
+
+	log_test "params default test"
+}
+
 check_region_size()
 {
 	local name=$1
-- 
2.47.3