fpga: microchip-spi: move SPI I/O buffers out of stack

As spi-summary doc says:
 > I/O buffers use the usual Linux rules, and must be DMA-safe.
 > You'd normally allocate them from the heap or free page pool.
 > Don't use the stack, or anything that's declared "static".

Replace spi_write() with spi_write_then_read(), which is dma-safe for
on-stack buffers. Use cacheline aligned buffers for transfers used in
spi_sync_transfer().

Although everything works OK with stack-located I/O buffers, better
follow the doc to be safe.

Fixes: 5f8d4a900830 ("fpga: microchip-spi: add Microchip MPF FPGA manager")
Signed-off-by: Ivan Bornyakov <[email protected]>
Acked-by: Conor Dooley <[email protected]>
Acked-by: Xu Yilun <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Xu Yilun <[email protected]>

0 files changed, 0 insertions, 0 deletions