spi: spi-sun6i: implement DMA-based transfer mode

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DMA-based transfer will be enabled if data length is larger than FIFO size
(64 bytes for A64). This greatly reduce number of interrupts for
transferring data.

For smaller data size PIO mode will be used. In PIO mode whole buffer will
be loaded into FIFO.

If driver failed to request DMA channels then it fallback for PIO mode.

Tested on SOPINE (https://www.pine64.org/sopine/)

Signed-off-by: Alexander Kochetkov <al.kochet@gmail.com>
Acked-by: Maxime Ripard <mripard@kernel.org>
Link: https://lore.kernel.org/r/20201022075221.23332-1-akochetkov@lintech.ru
Signed-off-by: Mark Brown <broonie@kernel.org>

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Alexander Kochetkov 2020-10-22 10:52:21 +03:00 • committed by Mark Brown

parent 2ee1b42e8a

commit 345980a3a5

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drivers/spi/spi-sun6i.c

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