nfp: devlink: add 'fw_load_policy' support

Add support for the 'fw_load_policy' devlink parameter. The FW load
policy is controlled by the 'app_fw_from_flash' hwinfo key.

Remap the values from devlink to the hwinfo key and back.
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>

Documentation/networking/devlink-params-nfp.txt

+fw_load_policy		[DEVICE, GENERIC]
+			Configuration mode: permanent

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

@@ -3,10 +3,175 @@
 
 #include <net/devlink.h>
 
+#include "nfpcore/nfp.h"
 #include "nfpcore/nfp_nsp.h"
 #include "nfp_main.h"
 
+/**
+ * struct nfp_devlink_param_u8_arg - Devlink u8 parameter get/set arguments
+ * @hwinfo_name:	HWinfo key name
+ * @default_hi_val:	Default HWinfo value if HWinfo doesn't exist
+ * @invalid_dl_val:	Devlink value to use if HWinfo is unknown/invalid.
+ *			-errno if there is no unknown/invalid value available
+ * @hi_to_dl:	HWinfo to devlink value mapping
+ * @dl_to_hi:	Devlink to hwinfo value mapping
+ * @max_dl_val:	Maximum devlink value supported, for validation only
+ * @max_hi_val:	Maximum HWinfo value supported, for validation only
+ */
+struct nfp_devlink_param_u8_arg {
+	const char *hwinfo_name;
+	const char *default_hi_val;
+	int invalid_dl_val;
+	u8 hi_to_dl[4];
+	u8 dl_to_hi[4];
+	u8 max_dl_val;
+	u8 max_hi_val;
+};
+
+static const struct nfp_devlink_param_u8_arg nfp_devlink_u8_args[] = {
+	[DEVLINK_PARAM_GENERIC_ID_FW_LOAD_POLICY] = {
+		.hwinfo_name = "app_fw_from_flash",
+		.default_hi_val = NFP_NSP_APP_FW_LOAD_DEFAULT,
+		.invalid_dl_val = -EINVAL,
+		.hi_to_dl = {
+			[NFP_NSP_APP_FW_LOAD_DISK] =
+				DEVLINK_PARAM_FW_LOAD_POLICY_VALUE_DISK,
+			[NFP_NSP_APP_FW_LOAD_FLASH] =
+				DEVLINK_PARAM_FW_LOAD_POLICY_VALUE_FLASH,
+			[NFP_NSP_APP_FW_LOAD_PREF] =
+				DEVLINK_PARAM_FW_LOAD_POLICY_VALUE_DRIVER,
+		},
+		.dl_to_hi = {
+			[DEVLINK_PARAM_FW_LOAD_POLICY_VALUE_DRIVER] =
+				NFP_NSP_APP_FW_LOAD_PREF,
+			[DEVLINK_PARAM_FW_LOAD_POLICY_VALUE_FLASH] =
+				NFP_NSP_APP_FW_LOAD_FLASH,
+			[DEVLINK_PARAM_FW_LOAD_POLICY_VALUE_DISK] =
+				NFP_NSP_APP_FW_LOAD_DISK,
+		},
+		.max_dl_val = DEVLINK_PARAM_FW_LOAD_POLICY_VALUE_DISK,
+		.max_hi_val = NFP_NSP_APP_FW_LOAD_PREF,
+	},
+};
+
+static int
+nfp_devlink_param_u8_get(struct devlink *devlink, u32 id,
+			 struct devlink_param_gset_ctx *ctx)
+{
+	const struct nfp_devlink_param_u8_arg *arg;
+	struct nfp_pf *pf = devlink_priv(devlink);
+	struct nfp_nsp *nsp;
+	char hwinfo[32];
+	long value;
+	int err;
+
+	if (id >= ARRAY_SIZE(nfp_devlink_u8_args))
+		return -EOPNOTSUPP;
+
+	arg = &nfp_devlink_u8_args[id];
+
+	nsp = nfp_nsp_open(pf->cpp);
+	if (IS_ERR(nsp)) {
+		err = PTR_ERR(nsp);
+		nfp_warn(pf->cpp, "can't access NSP: %d\n", err);
+		return err;
+	}
+
+	snprintf(hwinfo, sizeof(hwinfo), arg->hwinfo_name);
+	err = nfp_nsp_hwinfo_lookup_optional(nsp, hwinfo, sizeof(hwinfo),
+					     arg->default_hi_val);
+	if (err) {
+		nfp_warn(pf->cpp, "HWinfo lookup failed: %d\n", err);
+		goto exit_close_nsp;
+	}
+
+	err = kstrtol(hwinfo, 0, &value);
+	if (err || value < 0 || value > arg->max_hi_val) {
+		nfp_warn(pf->cpp, "HWinfo '%s' value %li invalid\n",
+			 arg->hwinfo_name, value);
+
+		if (arg->invalid_dl_val >= 0)
+			ctx->val.vu8 = arg->invalid_dl_val;
+		else
+			err = arg->invalid_dl_val;
+
+		goto exit_close_nsp;
+	}
+
+	ctx->val.vu8 = arg->hi_to_dl[value];
+
+exit_close_nsp:
+	nfp_nsp_close(nsp);
+	return err;
+}
+
+static int
+nfp_devlink_param_u8_set(struct devlink *devlink, u32 id,
+			 struct devlink_param_gset_ctx *ctx)
+{
+	const struct nfp_devlink_param_u8_arg *arg;
+	struct nfp_pf *pf = devlink_priv(devlink);
+	struct nfp_nsp *nsp;
+	char hwinfo[32];
+	int err;
+
+	if (id >= ARRAY_SIZE(nfp_devlink_u8_args))
+		return -EOPNOTSUPP;
+
+	arg = &nfp_devlink_u8_args[id];
+
+	nsp = nfp_nsp_open(pf->cpp);
+	if (IS_ERR(nsp)) {
+		err = PTR_ERR(nsp);
+		nfp_warn(pf->cpp, "can't access NSP: %d\n", err);
+		return err;
+	}
+
+	/* Note the value has already been validated. */
+	snprintf(hwinfo, sizeof(hwinfo), "%s=%u",
+		 arg->hwinfo_name, arg->dl_to_hi[ctx->val.vu8]);
+	err = nfp_nsp_hwinfo_set(nsp, hwinfo, sizeof(hwinfo));
+	if (err) {
+		nfp_warn(pf->cpp, "HWinfo set failed: %d\n", err);
+		goto exit_close_nsp;
+	}
+
+exit_close_nsp:
+	nfp_nsp_close(nsp);
+	return err;
+}
+
+static int
+nfp_devlink_param_u8_validate(struct devlink *devlink, u32 id,
+			      union devlink_param_value val,
+			      struct netlink_ext_ack *extack)
+{
+	const struct nfp_devlink_param_u8_arg *arg;
+
+	if (id >= ARRAY_SIZE(nfp_devlink_u8_args))
+		return -EOPNOTSUPP;
+
+	arg = &nfp_devlink_u8_args[id];
+
+	if (val.vu8 > arg->max_dl_val) {
+		NL_SET_ERR_MSG_MOD(extack, "parameter out of range");
+		return -EINVAL;
+	}
+
+	if (val.vu8 == arg->invalid_dl_val) {
+		NL_SET_ERR_MSG_MOD(extack, "unknown/invalid value specified");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
 static const struct devlink_param nfp_devlink_params[] = {
+	DEVLINK_PARAM_GENERIC(FW_LOAD_POLICY,
+			      BIT(DEVLINK_PARAM_CMODE_PERMANENT),
+			      nfp_devlink_param_u8_get,
+			      nfp_devlink_param_u8_set,
+			      nfp_devlink_param_u8_validate),
 };
 
 static int nfp_devlink_supports_params(struct nfp_pf *pf)