This commit adds a new driver category for memory controller
peripherals. There is no API involved for now, as it has not been found
necessary for first implementation.
STM32 Flexible Memory Controller (FMC) is the only controller supported
for now. This peripheral allows to access multiple types of external
memories, e.g. SDRAM, NAND, NOR Flash...
The initial implementation adds support for the SDRAM controller only.
The HAL API is used, so the implementation should be portable to other
STM32 series. It has only been tested on H7 series, so for now it can
only be enabled when working on H7.
Linker facilities have also been added in order to allow applications to
easily define a variable in SDRAM.
Signed-off-by: Gerard Marull-Paretas <gerard@teslabs.com>
Kumar Gala