drivers: stm32_risab: add RISAB internal memory firewall driver

This driver implements the RISAB driver. Through RISAB registers, a
trusted compartment, or the compartment to which the page configur

drivers: stm32_risab: add RISAB internal memory firewall driver

This driver implements the RISAB driver. Through RISAB registers, a
trusted compartment, or the compartment to which the page configuration
has been delegated, configures the firewall attributes necessary to
access a page.

Each RISAB is dedicated to a internal memory and can cover 128KBytes of
data, separated in 32 pages of 4 KBytes, containing 8 blocks each.

It is possible to align a RISAB secure and privilege regions
allocations with an ARM Cortex M, which defines in its address space
configurable regions with a 256Bytes granularity. The configuration
would be 512Bytes block-based in order to align the two.

Signed-off-by: Gatien Chevallier <gatien.chevallier@foss.st.com>
Reviewed-by: Etienne Carriere <etienne.carriere@foss.st.com>

show more ...