Hi Michael,
Op zo 10 nov. 2019 om 03:36 schreef Michael Schmitz <schmitzmic@xxxxxxxxx>:
All of the old board-specific drivers used a max transfer length of
0x1000000, only the fastlane driver used 0xfffc.
Yes, I also found this when checking the old drivers.
That lower limit might
be due to a DMA limitation on the fastlane board. We could accommodate
the different limit for this board by using a board-specific
dma_length_limit() callback...
Yes, I think that's the best idea for now. Oktagon also used to have a
different limit but that was never ported to the new ESP core.
case for any of the cards the zorro_esp drives, it might be better to
lower the max length to 61440 (64k-4k) so the residual is a page.
For the benefit of keeping the code simple, and avoid retesting the
fastlane board, that might indeed be the better solution.
But it's slower... :-P
Also, I may be adding another board-specific version for the Blizzard
12x0 IV to enable 24-bit transfers, like the am53c974 driver does, in
a later patch.
Kind regards,
Kars.
