The Radxa Rock Pi 4 board is sold from revision 1.4 with a soldered
4Mb SPI NOR Flash. This series allows to use it from U-Boot and boot
from it.
This series applies to u-boot/next.
Changes since v1:
- Changed bus number to 1 in SPL to match U-Boot proper (before it
was bus 0 in SPL and bus 1 in U-Boot).
- Generalization. v1 did a first soft_reset in 8_8_8_DTR but that
wouldn't work since Pratyush Yadav fixed supports_op() in commit
5752d6ae8daacbd ("spi: spi-mem: add spi_mem_dtr_supports_op()").
So now we try a few protocols until 1_1_1 is supported by
controller and device. Might work for more systems.
