net/mlx5: FPGA, Add SBU infrastructure

Add interface to initialize and interact with Innova FPGA SBU
connections.
A client driver may use these functions to set up a high-speed DMA
connection with its SBU hardware logic, and send/receive messages
over this connection.

A later patch in this patchset will make use of these functions for
Innova IPSec offload in mlx5 Ethernet driver.

Add commands to retrieve Innova FPGA SBU capabilities, and to
read/write Innova FPGA configuration space registers and memory,
over internal I2C.

At high level, the FPGA configuration space is divided such:
 0x00000000 - 0x007fffff is reserved for the SBU
 0x00800000 - 0xffffffff is reserved for the Shell
0x400000000 - ...        is DDR memory

A later patchset will add support for accessing FPGA CrSpace and memory
over a high-speed connection. This is the reason for the ACCESS_TYPE
enumeration, which currently only supports I2C.

Signed-off-by: Ilan Tayari <ilant@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
diff --git a/include/linux/mlx5/mlx5_ifc_fpga.h b/include/linux/mlx5/mlx5_ifc_fpga.h
index 0694077..a357665 100644
--- a/include/linux/mlx5/mlx5_ifc_fpga.h
+++ b/include/linux/mlx5/mlx5_ifc_fpga.h
@@ -150,6 +150,19 @@ struct mlx5_ifc_fpga_error_event_bits {
 	u8         reserved_at_60[0x80];
 };
 
+#define MLX5_FPGA_ACCESS_REG_SIZE_MAX 64
+
+struct mlx5_ifc_fpga_access_reg_bits {
+	u8         reserved_at_0[0x20];
+
+	u8         reserved_at_20[0x10];
+	u8         size[0x10];
+
+	u8         address[0x40];
+
+	u8         data[0][0x8];
+};
+
 enum mlx5_ifc_fpga_qp_state {
 	MLX5_FPGA_QPC_STATE_INIT    = 0x0,
 	MLX5_FPGA_QPC_STATE_ACTIVE  = 0x1,