dmaengine: sun6i: Choose appropriate burst length under maxburst

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[ Upstream commit 7178c3586a ]

maxburst, as provided by the client, specifies the largest amount of
data that is allowed to be transferred in one burst. This limit is
normally provided to avoid a data burst overflowing the target FIFO.
It does not mean that the DMA engine can only do bursts in that size.

Let the driver pick the largest supported burst length within the
given limit. This lets the driver work correctly with some clients that
give a large maxburst value. In particular, the 8250_dw driver will give
a quarter of the UART's FIFO size as maxburst. On some systems the FIFO
size is 256 bytes, giving a maxburst of 64 bytes, while the hardware
only supports bursts of up to 16 bytes.

Signed-off-by: Chen-Yu Tsai <wens@kernel.org>
Reviewed-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Link: https://patch.msgid.link/20251221080450.1813479-1-wens@kernel.org
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

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Chen-Yu Tsai 2025-12-21 16:04:48 +08:00 • committed by Sasha Levin

parent a49028a796

commit 340d7c73da

1 changed files with 20 additions and 6 deletions

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drivers/dma/sun6i-dma.c

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