mlxsw: reg: Add Management Capabilities Mask Register

MCAM register reports the device supported management features. Querying
this register exposes if features are supported with the current
firmware version in the current ASIC. Then, the driver can separate
between different implementations dynamically.

MCAM register supports querying whether the MCIA register supports 128
bytes payloads or only 48 bytes. Add support for the register as
preparation for allowing larger MCIA transactions.

Note that the access to the bits in the field 'mng_feature_cap_mask' is
not same to other mask fields in other registers. In most of the cases
bit #0 is the first one in the last dword, in MCAM register, bits #0-#31
are in the first dword and so on. Declare the mask field using bits
arrays per dword to simplify the access.
Signed-off-by: Amit Cohen <amcohen@nvidia.com>
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Petr Machata <petrm@nvidia.com>
Signed-off-by: Petr Machata <petrm@nvidia.com>
Link: https://lore.kernel.org/r/1427a3f57ba93db1c5dd4f982bfb31dd5c82356e.1690281940.git.petrm@nvidia.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

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

@@ -10581,6 +10581,79 @@ static inline void mlxsw_reg_mcda_pack(char *payload, u32 update_handle,
 		mlxsw_reg_mcda_data_set(payload, i, *(u32 *) &data[i * 4]);
 }
 
+/* MCAM - Management Capabilities Mask Register
+ * --------------------------------------------
+ * Reports the device supported management features.
+ */
+#define MLXSW_REG_MCAM_ID 0x907F
+#define MLXSW_REG_MCAM_LEN 0x48
+
+MLXSW_REG_DEFINE(mcam, MLXSW_REG_MCAM_ID, MLXSW_REG_MCAM_LEN);
+
+enum mlxsw_reg_mcam_feature_group {
+	/* Enhanced features. */
+	MLXSW_REG_MCAM_FEATURE_GROUP_ENHANCED_FEATURES,
+};
+
+/* reg_mcam_feature_group
+ * Feature list mask index.
+ * Access: Index
+ */
+MLXSW_ITEM32(reg, mcam, feature_group, 0x00, 16, 8);
+
+enum mlxsw_reg_mcam_mng_feature_cap_mask_bits {
+	/* If set, MCIA supports 128 bytes payloads. Otherwise, 48 bytes. */
+	MLXSW_REG_MCAM_MCIA_128B = 34,
+};
+
+#define MLXSW_REG_BYTES_PER_DWORD 0x4
+
+/* reg_mcam_mng_feature_cap_mask
+ * Supported port's enhanced features.
+ * Based on feature_group index.
+ * When bit is set, the feature is supported in the device.
+ * Access: RO
+ */
+#define MLXSW_REG_MCAM_MNG_FEATURE_CAP_MASK_DWORD(_dw_num, _offset)	 \
+	MLXSW_ITEM_BIT_ARRAY(reg, mcam, mng_feature_cap_mask_dw##_dw_num, \
+			     _offset, MLXSW_REG_BYTES_PER_DWORD, 1)
+
+/* The access to the bits in the field 'mng_feature_cap_mask' is not same to
+ * other mask fields in other registers. In most of the cases bit #0 is the
+ * first one in the last dword. In MCAM register, the first dword contains bits
+ * #0-#31 and so on, so the access to the bits is simpler using bit array per
+ * dword. Declare each dword of 'mng_feature_cap_mask' field separately.
+ */
+MLXSW_REG_MCAM_MNG_FEATURE_CAP_MASK_DWORD(0, 0x28);
+MLXSW_REG_MCAM_MNG_FEATURE_CAP_MASK_DWORD(1, 0x2C);
+MLXSW_REG_MCAM_MNG_FEATURE_CAP_MASK_DWORD(2, 0x30);
+MLXSW_REG_MCAM_MNG_FEATURE_CAP_MASK_DWORD(3, 0x34);
+
+static inline void
+mlxsw_reg_mcam_pack(char *payload, enum mlxsw_reg_mcam_feature_group feat_group)
+{
+	MLXSW_REG_ZERO(mcam, payload);
+	mlxsw_reg_mcam_feature_group_set(payload, feat_group);
+}
+
+static inline void
+mlxsw_reg_mcam_unpack(char *payload,
+		      enum mlxsw_reg_mcam_mng_feature_cap_mask_bits bit,
+		      bool *p_mng_feature_cap_val)
+{
+	int offset = bit % (MLXSW_REG_BYTES_PER_DWORD * BITS_PER_BYTE);
+	int dword = bit / (MLXSW_REG_BYTES_PER_DWORD * BITS_PER_BYTE);
+	u8 (*getters[])(const char *, u16) = {
+		mlxsw_reg_mcam_mng_feature_cap_mask_dw0_get,
+		mlxsw_reg_mcam_mng_feature_cap_mask_dw1_get,
+		mlxsw_reg_mcam_mng_feature_cap_mask_dw2_get,
+		mlxsw_reg_mcam_mng_feature_cap_mask_dw3_get,
+	};
+
+	if (!WARN_ON_ONCE(dword >= ARRAY_SIZE(getters)))
+		*p_mng_feature_cap_val = getters[dword](payload, offset);
+}
+
 /* MPSC - Monitoring Packet Sampling Configuration Register
  * --------------------------------------------------------
  * MPSC Register is used to configure the Packet Sampling mechanism.
@@ -12977,6 +13050,7 @@ static const struct mlxsw_reg_info *mlxsw_reg_infos[] = {
 	MLXSW_REG(mcqi),
 	MLXSW_REG(mcc),
 	MLXSW_REG(mcda),
+	MLXSW_REG(mcam),
 	MLXSW_REG(mpsc),
 	MLXSW_REG(mgpc),
 	MLXSW_REG(mprs),