register: Define REG and FIELD macros

register: Define REG and FIELD macros

Define some macros that can be used for defining registers and fields.

The REG32 macro will define A_FOO, for the byte address of a register
as well as R_FOO for the uint32_t[] register number (A_FOO / 4).

The FIELD macro will define FOO_BAR_MASK, FOO_BAR_SHIFT and
FOO_BAR_LENGTH constants for field BAR in register FOO.

Finally, there are some shorthand helpers for extracting/depositing
fields from registers based on these naming schemes.

Usage can greatly reduce the verbosity of device code.

The deposit and extract macros (eg FIELD_EX32, FIELD_DP32  etc.) can be
used to generate extract and deposits without any repetition of the name
stems.

Signed-off-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Alistair Francis <alistair.francis@xilinx.com>
Signed-off-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
Message-id: bbd87a3c03b1f173b1ed73a6d502c0196c18a72f.1467053537.git.alistair.francis@xilinx.com
[ EI Changes:
  * Add Deposit macros
]
Signed-off-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
Signed-off-by: Alistair Francis <alistair.francis@xilinx.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>