There are almost certainly ways to make this work, but they may take some non-trivial engineering.

Understand and work around the SPI issues. They mostly have to do with simultaneous write/read operations and long transfers, both of which can usually be avoided at the cost of some efficiency Proxy the SPI through something else, for example a fixed-function chip (FTDI, etc) or a small MCU, hanging off either the USB or one of the UARTs See if you can use the I2S interface instead - this is normally meant to move audio data but it is not dissimilar to SPI. Many chips have offered functional blocks that did both SPI and I2S by configuring different details, which may be well within the range of what you can do with clever software Bitbang SPI on arbitrary GPIOs. Probably slow, though you can do the actually twiddling in kernel mode