nfp: add devlink param infrastructure

Register devlink parameters for driver use. Subsequent patches will add
support for specific parameters.

In order to support devlink parameters, the management firmware needs to
be able to lookup and set hwinfo keys.
Signed-off-by: Dirk van der Merwe <dirk.vandermerwe@netronome.com>
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Simon Horman <simon.horman@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/netronome/nfp/Makefile

@@ -17,6 +17,7 @@ nfp-objs := \
 	    nfpcore/nfp_target.o \
 	    ccm.o \
 	    ccm_mbox.o \
+	    devlink_param.o \
 	    nfp_asm.o \
 	    nfp_app.o \
 	    nfp_app_nic.o \

drivers/net/ethernet/netronome/nfp/devlink_param.c

+// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+/* Copyright (C) 2019 Netronome Systems, Inc. */
+
+#include <net/devlink.h>
+
+#include "nfpcore/nfp_nsp.h"
+#include "nfp_main.h"
+
+static const struct devlink_param nfp_devlink_params[] = {
+};
+
+static int nfp_devlink_supports_params(struct nfp_pf *pf)
+{
+	struct nfp_nsp *nsp;
+	bool supported;
+	int err;
+
+	nsp = nfp_nsp_open(pf->cpp);
+	if (IS_ERR(nsp)) {
+		err = PTR_ERR(nsp);
+		dev_err(&pf->pdev->dev, "Failed to access the NSP: %d\n", err);
+		return err;
+	}
+
+	supported = nfp_nsp_has_hwinfo_lookup(nsp) &&
+		    nfp_nsp_has_hwinfo_set(nsp);
+
+	nfp_nsp_close(nsp);
+	return supported;
+}
+
+int nfp_devlink_params_register(struct nfp_pf *pf)
+{
+	struct devlink *devlink = priv_to_devlink(pf);
+	int err;
+
+	err = nfp_devlink_supports_params(pf);
+	if (err <= 0)
+		return err;
+
+	err = devlink_params_register(devlink, nfp_devlink_params,
+				      ARRAY_SIZE(nfp_devlink_params));
+	if (err)
+		return err;
+
+	devlink_params_publish(devlink);
+	return 0;
+}
+
+void nfp_devlink_params_unregister(struct nfp_pf *pf)
+{
+	int err;
+
+	err = nfp_devlink_supports_params(pf);
+	if (err <= 0)
+		return;
+
+	devlink_params_unregister(priv_to_devlink(pf), nfp_devlink_params,
+				  ARRAY_SIZE(nfp_devlink_params));
+}

drivers/net/ethernet/netronome/nfp/nfp_main.h

@@ -187,4 +187,7 @@ int nfp_shared_buf_pool_get(struct nfp_pf *pf, unsigned int sb, u16 pool_index,
 int nfp_shared_buf_pool_set(struct nfp_pf *pf, unsigned int sb,
 			    u16 pool_index, u32 size,
 			    enum devlink_sb_threshold_type threshold_type);
+
+int nfp_devlink_params_register(struct nfp_pf *pf);
+void nfp_devlink_params_unregister(struct nfp_pf *pf);
 #endif /* NFP_MAIN_H */

drivers/net/ethernet/netronome/nfp/nfp_net_main.c

@@ -709,6 +709,10 @@ int nfp_net_pci_probe(struct nfp_pf *pf)
 	if (err)
 		goto err_devlink_unreg;
 
+	err = nfp_devlink_params_register(pf);
+	if (err)
+		goto err_shared_buf_unreg;
+
 	mutex_lock(&pf->lock);
 	pf->ddir = nfp_net_debugfs_device_add(pf->pdev);
 
@@ -742,6 +746,8 @@ int nfp_net_pci_probe(struct nfp_pf *pf)
 err_clean_ddir:
 	nfp_net_debugfs_dir_clean(&pf->ddir);
 	mutex_unlock(&pf->lock);
+	nfp_devlink_params_unregister(pf);
+err_shared_buf_unreg:
 	nfp_shared_buf_unregister(pf);
 err_devlink_unreg:
 	cancel_work_sync(&pf->port_refresh_work);
@@ -771,6 +777,7 @@ void nfp_net_pci_remove(struct nfp_pf *pf)
 
 	mutex_unlock(&pf->lock);
 
+	nfp_devlink_params_unregister(pf);
 	nfp_shared_buf_unregister(pf);
 	devlink_unregister(priv_to_devlink(pf));