On Sun, Mar 15, 2020 at 10:32:39PM -0400, Sasha Levin wrote:
> From: Vignesh Raghavendra <vigneshr-l0cyMroinI0@public.gmane.org>
> 
> [ Upstream commit e4e8276a4f652be2c7bb783a0155d4adb85f5d7d ]
> 
> On AM654, McSPI can only support 4K - 1 bytes per transfer when DMA is
> enabled. Therefore populate master->max_transfer_size callback to
> inform client drivers of this restriction when DMA channels are
> available.

As ever this only provides information to other drivers which may be
buggy.