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7d7c262975
This fixes tx and bi-directional dma transfers on rk3399-gru-kevin. It seems the SPI fifo must have room for 2 bursts when the dma_tx_req signal is generated or it might skip some words. This in turn makes the rx dma channel never complete for bi-directional transfers. Fix it by setting tx burst length to fifo_len / 4 and the dma watermark to fifo_len / 2. However the rk3399 TRM says (sic): "DMAC support incrementing-address burst and fixed-address burst. But in the case of access SPI and UART at byte or halfword size, DMAC only support fixed-address burst and the address must be aligned to word." So this relies on fifo_len being a multiple of 16 such that the burst length (= fifo_len / 4) is a multiple of 4 and the addresses will be word-aligned. Change-Id: I7dd843e85e4d888af79ec57a73d1561f8402635e Fixes:dcfc861d24("spi: rockchip: adjust dma watermark and burstlen") Signed-off-by: Emil Renner Berthing <kernel@esmil.dk> Signed-off-by: Mark Brown <broonie@kernel.org> Signed-off-by: Jon Lin <jon.lin@rock-chips.com> (cherry picked from commit47300728fb)
Linux kernel
============
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