soc/amd/common/psp_smi_flash: add spi_controller_available

The SPI_SEMAPHORE_DRIVER_LOCKED bit in the SPI_MISC_CNTRL register
doesn't affect the hardware, but it re-used by AMD as a semaphore to
synchronize the access to the SPI controller between SMM and non-SMM
software like an OS-level driver. Since it doesn't affect the hardware,
it's marked as reserved in the PPRs. Add the 'spi_controller_available'
helper function to check this bit to see if some software or driver
outside of SMM is currently using the SPI flash controller to avoid
interfering with that operation.

This patch is a slightly reworked version of parts of CB:65523.

Test=When selecting SOC_AMD_COMMON_BLOCK_PSP_SMI, Mandolin still builds

Signed-off-by: Felix Held <felix-coreboot@felixheld.de>
Signed-off-by: Ritul Guru <ritul.bits@gmail.com>
Change-Id: I49218e03a5dd555b2b2d34eaad86673e9fc908c3
Reviewed-on: https://review.coreboot.org/c/coreboot/+/83775
Reviewed-by: Martin Roth <martin.roth@amd.corp-partner.google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

0 files changed, 0 insertions, 0 deletions